PTV Vistro 4 Manual

PTV VISTRO USER MANUAL

Structure

PTV VISTRO USER MANUAL

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COPYRIGHT © 2016 PTV AG, Karlsruhe All brand or product names in this documentation are trademarks or registered trademarks of the corresponding companies or organizations. All rights reserved. DISCLAIMER The information contained in this document is subject to change without notice and should not be construed as a commitment on the part of the vendor. This document may not be used for any other purpose than the personal use of the purchaser. No part of this handbook may be reproduced, stored in a retrieval system, or transmitted, in any form, or by any means, electronic, mechanical, photocopying, recording, or otherwise, edited or translated, except as permitted under the terms of the copyright, without the prior written permission of PTV AG. © February 2016, PTV AG COPY AND USE Although you are encouraged to make a backup copy of PTV Vistro for your own use, you are not allowed to make more than one copy. The Software may be used only on a single computer owned, leased or controlled by you at any one time. The Software is protected by the copyright laws that pertain to computer Software. It is illegal to submit copies to another person, or to duplicate the Software by any other means including electronic transmission. The Software contains trade secrets, and in order to protect them you may not decompile, reverse engineer, disassemble, or otherwise reduce the Software to human-perceivable form. You may not modify, adapt, translate, rent, lease, or create derivative work based upon the Software or any part thereof. DISK WARRANTY PTV Group (respectively the agent distributing Vistro) warrants that the original disks are free from defects in material and workmanship, assuming normal use, for a period of ninety (90) days from date of purchase. If a defect occurs during this period, you may return your faulty disk to your local distributor, along with a dated proof of purchase; you will receive a replacement free of charge. EXCEPT FOR THE EXPRESS WARRANTY OF THE ORIGINAL DISKS SET FORTH ABOVE, NEITHER PTV GROUP NOR ANY OF THEIR DISTRIBUTORS GRANTS ANY OTHER WARRANTIES, EXPRESS OR IMPLIED, BY STATUTE OR OTHERWISE, REGARDING THE DISKS OR RELATED MATERIALS, THEIR FITNESS FOR ANY PURPOSE, THEIR QUALITY, THEIR MERCHANTABILITY, OR OTHERWISE. THE LIABILITY OF PTV GROUP UNDER THE WARRANTY SET FORTH ABOVE SHALL BE LIMITED TO THE AMOUNT PAID BY THE CUSTOMER FOR THE PRODUCT. IN NO EVENT SHALL PTV BE LIABLE FOR ANY SPECIAL, CONSEQUENTIAL, OR OTHER DAMAGES FOR BREACH OF WARRANTY.

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IMPRINT PTV AG Traffic Software Haid-und-Neu-Straße 15 D - 76131 Karlsruhe Germany Phone +49 721 9651-300 Fax +49 721 9651-562 E-Mail: [email protected] www.ptvgroup.com vision-traffic.ptvgroup.com

In association with PTV America, Inc. 9755 SW Barnes Road, Suite 550 Portland, Oregon 97225 (503) 297-2556

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Structure 1

Quick Start Checklist ................................................................................................ 11

2

Introduction ............................................................................................................... 14

3

Installation ................................................................................................................. 17

4

Getting Started .......................................................................................................... 23

5

Moving Around Inside Vistro .................................................................................... 26

6

Global Settings .......................................................................................................... 34

7

Network Building....................................................................................................... 36

8

Base Model Development ......................................................................................... 49

9

Traffic Impact Analysis (TIA) .................................................................................... 94

10

Signal Optimization................................................................................................. 101

11

Mitigation ................................................................................................................. 126

12

Reporting ................................................................................................................. 128

13

Scenario Management ............................................................................................ 146

14

Import/Export...........................................................................................................150

15

Analysis Methods .................................................................................................... 154

16

Vistro Shortcuts ...................................................................................................... 207

17

Service & Support ................................................................................................... 209

18

Index.........................................................................................................................210

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Contents 1

2

3

4

5

Quick Start Checklist ................................................................................................ 11 1.1

Analyzing the Base Conditions ...................................................................... 11

1.2

Analyzing Additional Base Conditions or Future Conditions .......................... 11

1.3

Mitigate Future Conditions ............................................................................ 12

1.4

Optional: Optimize Traffic Signal Timing........................................................ 12

1.5

Optional: Conduct a Traffic Impact Analysis .................................................. 12

1.6

Optional: View Animation with Quick-Vissim Tool .......................................... 13

1.7

Optional: Export to Vissim Microsimulation.................................................... 13

Introduction............................................................................................................... 14 2.1

Software Overview ........................................................................................ 14

2.2

Program Documentation ............................................................................... 15

2.3

Network and Other Limits .............................................................................. 15

Installation................................................................................................................. 17 3.1

How to install................................................................................................. 17

3.2

System Requirements ................................................................................... 21

Getting Started .......................................................................................................... 23 4.1

Starting Vistro ............................................................................................... 23

4.2

File Structure................................................................................................. 23

4.3

Types of Analyses ......................................................................................... 24

Moving Around Inside Vistro ................................................................................... 26 5.1

Window Interface Descriptions ...................................................................... 26

6

Global Settings ......................................................................................................... 34

7

Network Building ...................................................................................................... 36 7.1

Select your Network Background .................................................................. 36

7.2

Add your Intersections................................................................................... 41

7.3

Complete your Street Network ...................................................................... 44

7.4

Add Zones to Represent your Development Sites ......................................... 46

7.5

Add Gates for Routing of Development Traffic .............................................. 47

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8

9

10

7.6

Define Paths for Assigning Development Traffic to your Street Network ........ 47

7.7

Translating Networks ..................................................................................... 48

Base Model Development ......................................................................................... 49 8.1

Intersection Setup (Geometry) ....................................................................... 49

8.2

Volumes ........................................................................................................ 61

8.3

Traffic Control ................................................................................................ 64

Traffic Impact Analysis (TIA) .................................................................................... 94 9.1

Trip Generation.............................................................................................. 94

9.2

Trip Distribution ............................................................................................. 95

9.3

Trip Assignment ............................................................................................. 98

Signal Optimization................................................................................................. 101 10.1

Local Optimization ....................................................................................... 101

10.2

Network Optimization ................................................................................... 108

11

Mitigation ................................................................................................................. 126

12

Reporting ................................................................................................................. 128

13

14

12.1

Report Layout .............................................................................................. 128

12.2

Vistro Report Contents ................................................................................ 131

12.3

Analysis Results .......................................................................................... 131

12.4

Graphical Reports........................................................................................ 140

12.5

Vissim Previewer ......................................................................................... 145

Scenario Management ............................................................................................ 146 13.1

Base Scenario ............................................................................................. 146

13.2

Creating Additional Scenarios ...................................................................... 147

13.3

Selecting the Active Scenario ...................................................................... 147

13.4

Reporting by Scenario ................................................................................. 148

13.5

Mitigation by Scenario ................................................................................. 148

13.6

File Structure for Scenarios ......................................................................... 148

Import/Export...........................................................................................................150 14.1

Vision Traffic Suite....................................................................................... 150

14.2

External Interfaces....................................................................................... 151

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15

16

Analysis Methods ................................................................................................... 154 15.1

Signalized Intersection Analysis Methods.................................................... 154

15.2

Roundabout Intersection Analysis ............................................................... 179

15.3

Two-Way Stop Control (TWSC) Intersection Analysis ................................. 189

15.4

All-Way Stop Control (AWSC) Intersection Analysis .................................... 198

Vistro Shortcuts ...................................................................................................... 207 16.1

17

18

Network Window Shortcuts ......................................................................... 207

Service & Support................................................................................................... 209 17.1

Online Help ................................................................................................. 209

17.2

About PTV Vistro......................................................................................... 209

Index ........................................................................................................................ 210

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Quick Start Checklist

1


This quick start checklist will help you build your network and proceeding through your typical project in the most efficient order.

1.1

Analyzing the Base Conditions

1. Open Vistro and save a new file (File ( File > Save). Save). 2. Zoom and Pan to view study area in Network window:

3. Define your Global Settings ( Edit > Global Settings…) 4. Add intersections intersectio ns to your network A. Select the Intersection Intersection tool from from the Toolbox Toolbox

.

B. Place Intersection in the Network window. C. Repeat for all study intersections intersecti ons ( tip: holding CTRL key while placing intersections allows for multiple placements without having to select the intersection tool each time ). 5. Connect intersections by clicking and dragging intersection legs to overlap

. 6. Define the intersection intersecti on geometry by using the Intersection Setup workflow table

.

7. Enter traffic volume data and adjustments using the Volumes workflow table 8. Input traffic control parameters in the Traffic Control workflow table

.

.

9. Generate your Base Conditions Analysis Report (File ( File > Print Report) Report )

1.2

Analyzing Additional Base Conditions or Future Conditions

1. Add a Scenario using the Scenario drop-down

and

selecting the Add Scenario button . Rename the new scenario name (right-click, (right-c lick, rename) to describe this scenario (e.g., “AM Peak”). 2. Code any geometry, volume, or traffic control changes for this condition using the workflow tables.

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1.3

Mitigate Future Conditions

1. Select the intersection intersecti on to mitigate. 2. Create and evaluate mitigation options using the Mitigation workflow table

.

3. Report mitigation options using the Print Report buttons in the Mitigation table.

1.4

Optional: Optimize Traffic Signal Timing

1. Create or select the scenario you want to optimize. 2. Define Optimization Routes using the Routes tool from the Toolbox 3. Define parameters in the Network Optimization Optimizati on workflow table

. .

4. Select optimization parameters and run optimization optimization by selecting the Network Optimization button in the Network Optimization Optimizati on workflow table (or from Signal Control > Network Optimization). Optimization ). Report ). 5. Generate your Scenario Analysis Report ( File > Print Report).

1.5

Optional: Conduct a Traffic Impact Analysis Analysis

1. Create or select the scenario for your Traffic Impact Analysis (TIA). 2. Code any network or other parameter updates for the Future Development conditions. 3. Create the Zone and Gate structure using Zone

and Gate

tools from the Toolbox.

4. Enter trip generation data in the Trip Generation

workflow table.

5. Enter trip distribution distributi on data in the Trip Distribution Distributi on

workflow table.

6. Define Paths between Zone and Gate pairs using Path tool from the Toolbox (tip: shortest path between each zone and gate can be automatically created by clicking the Add Missing Paths button Paths button in the Trip Assignment workflow table). 7. Enter trip assignment volume share percentages percentages for each Zone – Gate pair in the Trip Assignment Assignment workflow table table (tip: clicking on a row in this workflow workflow table will display the path graphically in the network window). 8. Repeat this for additional Future Development scenario analysis. 9. Mitigate future development conditions, as required. 10. Generate your Future Development Conditions Report ( File > Print Report). Report ).

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1.6 

Select Quick-Vissim Quick-Viss im tool from the Simulation > Preview in Vissim to view animation.

1.7 

Optional: View Animation Animation with Quick-Vissim Tool

Optional: Export to Vissim Microsimulation Microsimulation

Export Vistro model to Vissim microsimulation software software for detailed queuing and operations analysis ( File > Export > Vissim (ANM)). (ANM) ).

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Introduction

2

Introduction

2.1

Software Overview

PTV Vistro is a complete traffic analysis solution giving you all the tools necessary to complete traffic engineering and transportation planning studies and evaluations. With PTV Vistro, you can evaluate development impacts, optimize and re-time traffic signals, evaluate intersection levels of service, and generate report-ready tables and figures. This makes it a useful tool for many different types of traffic and transportation studies, saving you time through its all-encompassing functionality. Specific tasks that you can complete using Vistro include: 

















Calculate Intersection Level of Service for signals, two-way stops, all-way stops, and roundabouts using industry standard methodologies, including HCM 2010, HCM 2000, CIrcular 212, Intersection Capacity Utilization (ICU), and Kimber methods. Optimize Signal Timing for Timing for individual intersections, routes, and networks using robust optimization techniques within user-defined timing parameters Evaluate the impacts of New Developments using Developments using the integrated Trip Generation, Trip Distribution, and Trip Assignment functionality to efficiently track trips through your network and analyze the impacts of the additional traffic Test Mitigation Options for Options for failing intersections and compare the various options to each other and the base network Manage Multiple Scenarios in Scenarios in One Location to maximize the efficiency of completing multiple time periods, horizon years, and alternatives Visualize Results on Results on your network or as graphical output for various volume levels, volume balancing results, LOS, and optimization Obtain Standardized Report-Ready Tables and Figures in Figures in one easy step to insert directly into any report to meet agency requirements Analyze Queues and Spillbacks via Spillbacks via quick export to Vissim for microsimulation Evaluate Need for a New Traffic Signal Traffic Signal through the built-in MUTCD Signal Warrants Analysis

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Introduction

2.2

Program Documentation

This Vistro User Manual describes the full feature set and functionality of Vistro. A brief outline of chapter topics is provided below. Chapters 1-4: Software introduction, capabilities, installation procedures, and getting started Chapter 5: User interface details Chapters 6-8: Description of steps necessary to begin building a Vistro network, including global parameters, creating network elements, and entering and editing network data Chapters 9: Traffic Impact Analysis (TIA) Chapter 10: Signal Optimization Chapter 11: Mitigation features Chapter 12: Reporting, including tables and figures Chapter 13: Scenario Management Chapter 14: Import and export options Chapter 15: Analysis methods Chapter 16: Tips and shortcuts Chapter 17: Service & Support The User Manual is provided in PDF format (UserManual_Vistro40.pdf) in the Doc folder of your Vistro installation directory (e.g. C:\Program Files\PTV Vision\PTV Vistro4\Doc). Hard copies can be purchased from PTV America by contacting [email protected]. The Online Help consists of the Vistro User Manual. To access the Online Help during your program session, select Help > Help, or use hotkey F1. A complete list of all changes and new functionality in Vistro compared to previous versions is contained in the file ReleaseNotes_Vistro_ENG.pdf in the \Doc directory of your Vistro install.

2.3

Network and Other Limits

Vistro has the following limits:

Network size: 

400 zones (zones and gates)



2,500 nodes



6,000 links

Intersection approaches: 

up to 8 legs

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Introduction

Signals: 

up to 4 rings and 8 barriers

Mitigations: 

up to 99 options per intersection

Scenarios: 

unlimited

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Installation

3

Installation

3.1

How to install

Before you start: 1. You must have administrator privileges when installing Vistro. If you are unsure of your user level, check the User Accounts under Control Panel or contact your administrator. 2. It is highly recommended that you close all other applications before beginning the installation. 3. Attach your hardware key to your computer. Make sure it is securely connected. For further information regarding hardware key installation, please refer to the document OVERVIEW_CODEMETER.PDF in the DOC folder of your Vistro installation and on the installation DVD.

Installation: 1. Insert the Vistro Installation DVD or select the SETUP*.exe downloaded from the customer download site. If the DVD does not start automatically, use Windows Explorer to open the DVD directory. Click on the SETUP*.EXE program to begin the installation. Depending on your license, use the SETUP with either WIN32 or X64 in the file name. If prompted, select Run or Yes.

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Installation

2. Select English and click the OK button when prompted.

3. Press Next > in the subsequent dialog.

4. Accept the general license conditions.

5. Select a folder where Vistro will be installed. Note: the default directory is recommended.

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Installation

6. You can choose between Standard installation, Full installation and Compact installation. Note: the Standard installation is recommended.

7. Additionally, you can select which components to include in the installation. Note: the available components depend on your license. 





Additional Data: includes symbols free for use with your Vistro projects (e.g. US state symbols). Examples: installs various sample Vistro networks and examples. Documentation: contains all the software documentation, including the user manual and release notes.

8. Select the Start Menu Folder for the program shortcuts.

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Installation

9. Specify if you want to add shortcuts to Vistro to the Windows Start menu, to the quick launch bar and/or to the desktop.

PTV Vistro is now ready to install. 10. Click on Install to continue.

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Installation

11. You should see the following dialog at the completion of the installation.

12. It is recommended to restart your computer after the installation.

3.2

System Requirements

System Requirements 

Vistro 4 is supported on Microsoft Windows Vista, Windows 7, Windows 8, and Windows 10. The 32 bit edition of Vistro runs on both 32 bit and 64 bit Windows. The 64 bit edition of Vistro runs only on 64 bit Windows.

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Installation





You must have administrator privileges when installing Vistro. If you are unsure of your user level, check the User Accounts under Control Panel or contact your administrator. The minimum screen resolution to run Vistro is 1280 x 800, the recommended screen resolution is 1600 x 1200 or 1920 x 1080.

Hardware Requirements 

Processor: min. Pentium IV; recommended: Core I or better



Speed: min. 2 GHz



Memory (RAM): min. 2 GB (4 GB for the 64-bit edition); recommended: 4-8 GB



Hard disk space: depending on the installation settings up to 1.5 GB



Hardware lock (dongle) protection: one fully functional USB port





Screen resolution: min. 1280x800 or 1366x768 Pixel; recommended: Full HD (1920x1080 Pixel) DirectX11 enabled graphics card

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Getting Started

4

Getting Started

4.1 

Starting Vistro

Open Vistro by double-clicking the Vistro icon

on your desktop.

Alternatively you may open Vistro by going to Start > All Programs > PTV Vision 2015 >PTV Vistro 4. Once Vistro has been started, the start screen appears providing the program version while the program is loading.

The graphical user interface of the program will then appear after loading. Details about working with the Vistro interface are described in Chapter 5 Moving Around Inside Vistro on page 26.

4.2

File Structure

All data for Vistro analysis is contained within the following file types: File Type

Extension

Description

Network

*.vistro

Single Vistro network file with no scenarios

Project

*.vistro

Vistro project file that contains multiple scenarios

Vistro 1 and Vistro 2 Project

*.vistropdb

In Vistro 1 and Vistro 2: Vistro project file that contains multiple scenarios

When new networks are created, Vistro saves a Network file with the .vistro extension. This file contains all the data necessary to perform an analysis is contained within this model file including the network, geometry, volume, intersection control, signal timing, trip generation/distribution, paths, and mitigation alternatives.

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Getting Started

When scenarios are created and managed, Vistro creates a Project file. When it is saved, it is zipped to one file with the extension *.vistro (note: in Vistro 1 and Vistro 2 projects were saved with the .vistropdb extension). When a Vistro file is opened, this file containing the scenario project directory structure is unzipped in a temporary local directory and the project is opened there. User-defined scenarios are described in Chapter 13 Scenario Management on page 146. There are several files external to the .vistro file that may be used when working with Vistro. These include background images and any associated image scaling files. Background images may also be loaded via an online connection to Bing™ Maps . Further details regarding background images can be found in Chapter Background Images on page 38. Reports generated from Vistro analysis are output to pdf, html and csv format. Further details regarding Vistro reports can be found in Chapter 12 Report on page 128. Vistro also interfaces with other file formats to import and export data, including PTV software and 3 rd party software. PTV software file formats include: 





Visum (*.ver) Abstract Network model (*.anm) Vissim (via *.anm format)

3rd Party file formats include: 

Synchro® (*.sy7, *.sy8)



OTISS (via *.xml)

Further details on importing and exporting data can be found in Chapter 14 Import/Export on page 150.

4.3

Types of Analyses

As a comprehensive traffic engineering and transportation planning analysis tool, you can use Vistro to perform the following tasks: 



Intersection Capacity and LOS Calculation: 

HCM 2010/2000



ICU



Circular 212



Kimber

Traffic Impact Analysis: 

Trip Generation

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Getting Started







Trip Distribution



Trip Assignment



Development Trip Tracking

Signal Timing Optimization: 

Intersection, Routes, Network



Cycles, Splits, Offsets, Lead / Lag

Signal Warrants Analysis 

MUTCD 2009

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Moving Around Inside Vistro

5 5.1

Moving Around Inside Vistro Window Interface Descriptions

The Vistro software User Interface contains the following (see Figure 1: Vistro Interface): Figure 1: Vistro Interface

(1) HEADER

Shows the Program Title, Version, Service Pack number, and Network Filename; for demo versions, “Demo” is added to the version number .

(2) MENU B AR

Contains drop-down menus, undo/redo shortcuts, scenario selector, intersection selector and the Vissim previewer.

(3) STATUS B AR

Displays the Scale Ratio

(current scale ratio display of the Network Area)

and the Coordinates location in the Network Area).

(x-y coordinates of the mouse

(4) NETWORK W INDOW

Displays the currently opened network, including the background map / image and representation of the roadway geometry. In this window, you can build and edit the network structure graphically, using the items from the Toolbar, as described in Chapter 7 Network on page 36. You can also move and adjust the display using the zoom and windowing tools.

(5) D ATA W INDOW

In this window, data is shown for the relevant task button selected. This will reflect associated data tables and functions specific to each task. Selection of a workflow Task Button results in the display of the related workflow table in the Data Window.

(6) TOOLBAR

Contains the tools for adding network objects.

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(7) W ORKFLOW P ANEL

Contains the tabs for data entry and analysis for various stages of the project workflow.

(8) GRAPHICS SELECTOR

Contains various graphical displays for the network window.

5.1.1

Menu Bar

The Menu Bar includes File, Edit, View, Optimization and Help. The table below provides a summary of each action available in the Menu Bar : File

General file management and printing commands

New

Initialize system (close network file without saving data, create new Vistro network).

Open

Open Vistro files (.vistro). Or, toggle to open Old PTV Vistro Scenario Project Files (*.vistropdb) from Vistro 1 or Vistro 2.

Save

Save network to current *.Vistro file.

Save As

Save network to selected path & file name. If a different path is chosen, the referenced files required by the network need to be copied manually to the new folder.

Print Report

Opens print report dialogue window (see Chapter 12 Report on page 128 for details).

Import

Read Synchro® data from file, load Abstract Network Model data from Vissim, or load Visum *.VER file (see Chapter 14 Import/Export on page 150 for details).

Export

Export data to Visum or to ANM (see Chapter 14 Import/Export on page 150 for details).

Exit

Terminate session, close Vistro.

Edit

Network editing commands

Undo

Undo functionality for construction element Editing: Undoes the previous action.

Redo

Redo functionality for construction element editing: Redoes the previously undone action.

Global Settings

Set global parameters for various inputs. Values entered here will be applied to all new intersections created. (see Chapter 6 Global Settings on page 34 for details).

View

Workspace Viewing Options

Network Statistics

Provides overview about the number of network elements (intersections, links, zones, gates, paths and routes) and network size.

Switch Table Position

Re-positions workflow task table horizontally or vertically, depending on current view.

Message File

Displays current Vistro instance message file.

Log File

Displays current Vistro log file.

Signal Control

Signalization and Optimization Options and Parameters

Default Signalization

Creates default traffic signal phasing for signalized intersections, with options for leading or lagging left turns.

Network Optimization

Opens Network Optimization window. Allows for se lection of Genetic or Hill Climbing algorithms, and various parameters specific to each.

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Local Optimization

Opens Local Optimization window. Allows for parameter entries related to local optimization.

Coordination Groups

Opens Coordination Groups window to manage coordination groups.

Simulation

Simulation Integration Options

Preview in Vissim

Opens the network in a Vissim Previewer, starts visualization automatically.

Export to Vissim (ANM)

Export Network and Signal Control data to an ANM file that can be imported into Vissim for full simulation analysis.

Help

Commands and options for display on screen

PTV Vistro Help

Opens HTML interactive help file.

PTV Vistro Manual

Opens this PDF file.

Service Pack Download

Opens webpage for Vistro service pack d ownloads.

Technical Support

Opens webpage to submit a Vistro technical support ticket.

Examples

Opens the folder containing Vistro example files.

License

Shows license information. The Manage Licenses button opens a dialog with detailed information about the available dongles.

About PTV Vistro

Shows details of the current software version and license expiration.

Additional Menu Bar items include: Function Undo and Redo

Scenario Selector

Intersection Selector

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Description Provides quick access to undo or redo previous actions. Allows you to add and manage scenarios and then toggle between the various scenarios within the file. Displays the number and name of the currently selected intersection from the network window. Here, you can select any intersection within the network to make it the currently selected intersection for editing either by accessing the drop -down list of intersections using the arrow on the right side of the dialogue or typing in the number or name of the intersection to pull up a condensed list that matches the search.

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5.1.2

Network Window

Icon

Keyboard

Function

Description

Map Layers

Select which layers to view: Network, Bing Maps, Open Street Maps, Other Background Images; add Background Images.

Shift+Left Mouse

Zoom Window

Zoom to window by clicking and dragging to create a rectangular zoom area

n/a

Zoom Network

Zoom out to view entire network

Zoom Scale

Zoom to specific scale using a slider bar

Pan

Pan around the network in any direction

n/a

PgUp / PgDn; Center mouse scroll Arrow Keys; Center mouse button; CTRL+Left Mouse

5.1.3

Toolbar

The Toolbar contains the objects to build your network: Icon

Name

Description

Intersection

Insert an Intersection into the network. Selecting the most recently used Intersection type (default is Signal) or by click the arrow below in order to view and s elect the various intersection types, as described below.

Signal

Insert a signalized intersection into the network.

Two-way Stop

Insert a two-way stop controlled intersection into the network. Stop-controlled approaches are defined during the network setup, as desc ribed in Chapter 7 Network on page 36. Insert an all-way stop controlled intersection in the network.

All-way Stop Insert a roundabout intersection into the network. Roundabout

Unknown

Insert intersections into the network that do not require analysis. These are sometimes referred to as “dummy” nodes.

Zones

Insert a Zone into the network to represent a development location that generates trips on the network. Zones are not required when conducting analyses that do not include generated trips.

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Icon

Name

Description

Gates

Insert a Gate into the network at all end -points of the study network. Gates act as a terminus for the outbound trips from a Zone and a s tarting point for the inbound trips to a Zone. Gates are not required when c onducting analyses that do not include Zones.

Paths

Insert a Path on the network. Paths are user -defined connections linking Zones and Gates in the Network and are used to assign new trips to the network in conjunction with other program features (trip generation, trip distribution and trip assignment).

Routes

Routes are user-defined connections linking intersections that are used to define optimization routes. These are used in conjunction with Network Optimization (see Chapter 10 Signal Optimization on page 101).

5.1.4

Workflow Panel

The Workflow Panel has Basic Network, TIA, and Additional tabs: Base Network Workflow Tabs Intersection Setup

Input data for the intersection number, name, control type, analysis method, base turning movement volumes, and all geometric and physical data. Specific details are described in Section 8.1 Intersection Setup (Geometry) on page 49.

Volumes

Input expanded data for turning movement volumes, including adjustment factors, growth rates, and traffic impact analysis (TIA) demand components. Details are described in Section 8.2 Volumes on page 61.

Traffic Control

Input traffic control information for specific traffic c ontrol type and methodology and view the capacity analysis and results. Details are described in Section 8.3 Traffic Control on page 56.

TIA Workflow Tabs Trip Generation

Input trip generation characteristics for each Zone including land use and quantity, trip generation rates, percentage splits ins and outs, and calculated trips. Details are described in Chapter 9.1 Trip Generation on page 94.

Trip Distribution

Input the trip distribution to and from Zones and Gates. Details are described in Chapter 9.2 Trip Distribution page 95.

Trip Assignment

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Allocate path shares for each path created between each Zone and Gate. Details are described in Chapter 9.3 Trip Assignment page 98.

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Additional Workflow Tabs

5.1.5


Define optimization routes, view time-space diagrams, and run network optimization

Mitigation

Evaluate potential mitigation measures and interactively view the resulting changes to the intersection calculations such as delays, LOS, and queuing. Details are described in Chapter 11 Mitigation on page 126.

Graphics Selector

The graphics selector buttons allow you to toggle various parameters on in the network view, as described below: Icon

Name

Description

Show Turning Movements

Intersection turning movement volumes are displayed. Clicking the arrow below this button allows the selection of various values for the display, as described below.

Show Final Base Volume

When Show Turning Movements is toggled on and this is selected, the value “Final Base Volume” will be displayed.

Show In Process Volumes

When Show Turning Movements is toggled on and this is selected, the value “In-Process” will be displayed.

Show Net New Site Trips

When Show Turning Movements is toggled on and this is selected, the value “Net New Site Trips” will be displayed.

Show Other Volume

When Show Turning Movements is toggled on and this is selected, the value “Other Volume” will be displayed.

Show Future Total Volume

When Show Turning Movements is toggled on and this is selected, the value “Future Total Volume” will be displayed.

Show Signal Groups

The signal group numbers by movement are displayed.

Show Turn Traffic Conditions

Traffic conditions by turning movement are displayed. Clicking the arrow below this button allows the selection of various traffic condition values, as described below.

Show Movement LOS

When Show Turn Traffic Conditions is toggled on and this is selected, the value “Movement LOS” will be displayed.

Show Movement Delay

When Show Turn Traffic Conditions is toggled on and this is selected, the value “Movement Delay” will be displayed.

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Show Movement v/c

When Show Turn Traffic Conditions is toggled on and this is selected, the value “Movement v/c” will be displayed.

Show Intersection Info

Intersection information is displayed. Clicking the arrow below this button allows the selection of various intersection information, as described below.

Show Intersection Number

When Show Intersection Info is toggled on and this is selected, the value “Intersection Number” is displayed.

Show Intersection LOS

When Show Intersection Info is toggled on and this is selected, the value “Intersection LOS” is displayed. Level of service A, B, C, D, E or F and an associated color are based on the LOS calculation results.

Show Intersection Control Type

When Show Intersection Info is toggled on and this is selected, the “Intersection Control Type” is displayed by an icon representing signalized, two-way stop, all-way stop, roundabout, or unknown control.

Show Controller Number

When Show Intersection Info is toggled on and this is selected, the “Controller Number” is displayed.

Show Intersection Coordination Group Number

When Show Intersection Info is toggled on and this is selected, the “Intersection Coordination Group” used for signal timing optimization is displayed.

Show ICA Check

When Show Intersection Info is toggled on and this is selected, either a green circle with a white check mark will appear to signify that the intersection coding is sufficient to perform intersection capacity analysis, or a red circ le with a white “x” will appear to signify that the intersection is not coded sufficiently to perform intersection capacity analysis. A yellow warning symbol will appear, if the intersection capacity analysis is possible, but some settings seem to be questionable.

Show Traffic Conditions

The intersection LOS, average delay and V/C are displayed.

Show Unbalanced Flows

The comparison of link volumes from the entry of the link to the exit of the link (determined from the Final Base Volumes for the intersection turning movements) by direction is displayed.

Show Queue Length

The calculated 95th-Percentile Queue Length is displayed for each approach.

Show Street Name

The street name for any approach that has information entered and the Show Name option checked in the data tables is displayed.

Show Approach Traffic Conditions

The LOS, delay and v/c is shown for each approach.

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5.1.6

Functionality

Additional interface functions are shown in the table below: Function Select Workflow Tab Open

Description Display the related workflow in the Data Window Open the current table in a new window for flexible viewing and editing Expand / Collapse subtables in the Workflow Tab

Filter

Filter data in the table using this to access drop-down filter criteria

Select Cell

In the Data Window, cells can be selected for editing by mouse-clicking, and editing using either the keyboard or mouse, depending on the type of entry (numeric, checkbox, etc.).

Tab

Within each workflow Task table, the Tab key can be used to quickly position the cursor to the next cell in the table for editing.

Copy / Paste

Copy/paste functionality is available within each cell of the workflow Task table by using keystrokes of CTRL+C for copy and CTRL+V for paste, or by right-clicking the cell and selecting these options.

Multi Edit

Many workflow Task tables have cells that can be edited in “Multi Edit” mode by highlighting cells across a row (partial or full row selection) by clicking and dragging the mouse and entering a value in the Multi Edit cell that appears.

Context Menu

Right-click on a network object for context menu s elections such as Insert, Add, Delete.

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Global Settings

6

Global Settings

You can set certain parameters shown below as the default for new intersections added to the network. This is done through Edit > Global Settings. Table 1. Global Settings Parameter Set Global Parameter

Default Setting

Optional Settings

Language

English

Deutsch, Chinese, Index

Direction of Traffic

Right-hand traffic

Left-hand traffic

Unit

Imperial

Metric

Analysis Method for Signalized Intersections

HCM2010

HCM2000, ICU1, ICU2, Circular 212 Planning

Analysis Method for Un-Signalized Intersections

HCM2010

Analysis Method for Roundabouts

HCM2010

HCM2000

Kimber

Default Lane Width

12ft

Speed

30mph

Pedestrian Crosswalk Width

8ft

Right Turn on Red?

Yes

Splitter island Length

10ft

Any number

Splitter island Width

20ft

Any number

Heavy Vehicle Percentage

2%

0 – 100%

Growth Rate

1.00

>= 1.00

Default Ideal Saturation Flow rate, HCM

1900

Positive integer

Default Ideal Saturation Flow rate, ICU 1

1600

Positive integer

Default Ideal Saturation Flow rate, ICU 2

1600

Positive integer

Default PHF

1

0-1.00

15min

1hr

(Located in ) CBD?

Yes

No

Major Flow Direction

North-South

East-West

Northbound Signal Group

2

4, 6, 8

Northwestbound Signal Group

2

4, 6, 8

Lead/Lag Setting

Lead

Lag

Cycle Length

90s

0-255

Analysis Period

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Any number 1.00 – 255 mph Any number No

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Global Settings

Time of Day Pattern Coordinated

Time of Day Pattern Isolated, Free

Fixed Time

Fully Actuated, Semi-Actuated

Offset Reference

LeadGreen

Lag FO, Lag End, Coord End, Lag Coord Green

Permissive Mode

Single Band

Multi-Band

Intersection Lost Time

0s

0-(cycle length-0.1)s

Minimum Green

5s

0-255s

Amber

3s

0-255s

Allred

1s

0-255s

Vehicle Extension

3s

0-25.5s

Walk

5s

0-255s

Pedestrian Clearance

10s

0-255s

Street Name Font Size

8.0 pt

Coordination Type

Actuation Type

These parameters are described in detail in the relevant sections of the User Manual. Once these parameters are defined, they will be used as the default value for any new network object you create. These values can be changed at the local level at any time. When edits are made to the global settings while in the Base Scenario, the edited values are applied for all new network objects, whether in the Base Scenario or any other scenario. When edits are made to the global settings while in a different scenario, the edited values are applied for all new network objects in that specific scenario until the active scenario is changed to a different scenario. In any case, edits made in the global settings only apply to newly created network objects and are not applied retroactively to current objects already placed in the network at the time of the edit.

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Network Building

7

Network Building

Drawing networks in Vistro is a simple point and click operation like most modern windows based programs. This section provides a step by step guide to drawing networks in Vistro. Building your network can be completed in three basic steps: 1. Select your network background 2. Add your intersections 3. Complete your street network In addition, if you are conducting a TIA, you will also need to complete the following: 4. Add Zones to represent your development sites 5. Add Gates for routing of your development traffic 6. Define Paths for assigning the development traffic to your street network For signal optimization, you will also add the following: 7. Define Routes for signal timing optimization

7.1

Select your Network Background

The network background provides the visual foundation for drawing your street network, including intersection placement, definition of geometry, identification of development sites. With Vistro, you have three (3) options for your network background: 

Bing™ Maps



Open Street Map



Background Images

To select the type of background or to add your own background, select the dropdown menu for Map Layers in the upper right corner of the Network Window:

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Network Building

Here you can check the option to show the Network, select the Internet Map type, and insert Background Images.

7.1.1

Bing™ Maps and Satellite Imagery

Vistro includes a fully licensed internet feed from Bing™ that includes satellite aerial images and map labels. You can toggle these on and off using the My Network, Labels and Aerial Images selector (see Chapter 5.1.2 Network Window on page 29). These maps assist with orientation, network drawing and display. Upon opening (with a live internet connection), Vistro will display the Bing™ maps live feed. With the Bing™ maps, there are display options: 

Aerials and Road Map



Only Aerials



Only Road Map

To select the display options, go to the Map Layers dialogue, hover over the Internet Map option, and select the Map Type from the drop-down menu.

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Network Building

In addition, the opacity of the map layer can be adjusted by dragging the opacity slider to the left (-) or right (+).

Select the display option and then zoom to the study area location in the Network window with the Bing™ maps background to begin building your network, using the zoom and pan functions.

7.1.2

Open Street Map

Vistro includes the ability to use Open Street Map as a background in place of Bing™ Maps . To access Open Street Map, go to the Map Layers dialogue, hover over the Internet Map option, and select Open Street Map from the Map Type drop-down menu.

7.1.3

Background Images

You can use background images either in conjunction with or instead of the Bing™ Maps option. To insert a background image, complete the following steps: 1. Go to the Map Layers selection box. Page 38/211

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Network Building

2. Click on Insert Background Image. 3. Select your image file from the supported formats. The image now appears in your network view with a dashed blue line highlighting the outline of your image.

To move and adjust your image manually:

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Network Building

1. Left-click and drag to position the image. 2. Left-click on the outline to re-size the image. 3. Repeat these steps for multiple images, if required. To scale your image: 4. Right-click and select Scale Background Image. The cursor will turn to a ruler with a “+” sign. The “+” sign is the reference point. 5. Left-click, hold, and drag the cursor the length of the scaled feature on the background image. This can be either a normal map scale or between any two points where the distance is known. 6. Release the mouse and enter the selected distance in the Scale Background Image dialogue:

7. Select whether or not to apply the distance to other background images. 8. Click on OK.

The image(s) can also be layered with and without the Bing™ Maps or Satellite Imagery in the Map Layers dialog:

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Network Building

Here, you can change the layer order by using the up / down arrows. You can also toggle the layers on and off or remove your background image from your network using the Trash Can icon.

In this window, you can also adjust the opacity of each image and the Bing™ Maps imagery by sliding the Opacity bar to the left (-) and right (+).

7.2

Add your Intersections

Once you have the appropriate background image, your next step is to add the intersections to include in your network in the appropriate location. You can insert intersections using the toolbar or the context menu, as described below.

7.2.1

Inserting Intersections Using the Toolbar

1. Select the Intersection icon from the Toolbar.

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Network Building

2. Activate the desired intersection type if the current symbol is not the desired type. Intersection types are changed by clicking on the below the current intersection type icon and clicking on the desired intersection type from the list. 3. Left-click in the network window to place the intersection in the correct location. 4. To insert multiple intersections, hold down the CTRL key as you click in your network. This keeps the insert intersection active. When you are finished, deactivate the insert intersection using the ESC key on your keyboard or toggling the Insert Intersection button off on the toolbar.

7.2.2

Inserting Intersections Using the Context Menu

1. Right-click in the network window to open a context menu:

2. Select the required intersection by left-clicking the list of available types. 3. Repeat for each intersection. Once your intersections have been added, you can edit their location and configuration, as described in the following sub-sections.

7.2.3

Moving and Deleting Intersections with Node Handles

Each intersection in your network has a “Node Handle”. If you hover over the intersection, this Node Handle is shown as a dark blue circle at the center of the intersection. Left-clicking on this Node Handle selects the intersection for editing.

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Network Building

To move an intersection, simply left-click and drag the Node Handle to the new desired position in your network. To delete an intersection, select the intersection by clicking on the Node Handle. You can then use the Delete key or right-click and select Delete Intersection from the context menu.

7.2.4

Copying Intersections

Vistro allows you to copy complete intersections, providing a quick way to build a network with many similar intersections. When copied, all data (intersection setup, volumes, and traffic control) will be copied. To copy an intersection: 1. Select the intersection in the network window to copy by clicking on the Node Handle. 2. Copy the intersection by either right-clicking and selecting Copy Intersection from the context menu or by using CTRL+C. 3. Click in the network window at the desired location for the copied intersection. 4. Paste the intersection by either right-clicking and selecting Paste Intersection” from the context menu or by using CTRL+V.

7.2.5

Removing, Adding, and Moving Intersection Legs

Once intersections are added to your network, you can remove, add, and move the legs to reflect the true intersection geometry. Vistro is able to accommodate intersections with up to 8 legs.

7.2.5.1

Removing Intersection Legs

In addition to the “Node Handle”, each existing leg of your intersection has a “Leg Handle”. These Leg Handles are placed at the end of each leg. Hovering over the intersection will highlight all available Leg Handles in gray. As you hover over a specific Leg Handle, it will become active and shown in blue. These Leg Handles are similar but smaller than the Node Handle.

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Network Building

To remove a leg using the Leg Handle, follow these steps: 1. Select the leg by left-clicking to select the Leg Handle. 2. Delete the leg by using the Delete key on your keyboard or right-clicking to activate the context menu and select Delete Link and Legs.

7.2.5.2

Adding and Moving Intersection Legs

To add intersection legs, follow these steps: 1. Select the Node Handle for the intersection. 2. Right-click and select Add Leg. 3. Once the leg is in place, left-click and drag the Leg Handle to the appropriate position.

7.3

Complete your Street Network

You can now create a complete street network by connecting your intersections and adjusting the roadway to match the actual geometry. This is done in two steps: 1. Connect intersections 2. Add Poly Points Connect your intersections as follows: 1. Left-click over the unconnected intersection Leg Handle to select (highlighted blue).

2. While holding the left mouse button, drag and drop the Leg Handle over another the Leg Handle to connect the two and create a link between them. If you drag and drop the Leg Handle over a Node Handle, a new leg will be created for the Node Handle with a link between the Leg Handle and new Leg Handle.

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Network Building

You can adjust your roadway geometry by adding and editing Poly Points on the link between two connected intersections and on the leg to an isolated / disconnected intersection. Poly Points are shown as blue squares and you can add or delete as many as needed.

To add Poly Points automatically: 1. Left-click and drag any point on the link to create a Poly Point. 2. Continue to do this to achieve the desired roadway geometry. To add Poly Points using the context menu: 1. Left-click to highlight the leg or link (it will highlight in blue). 2. Right-click and select Insert Poly Point. To edit Poly Points: 1. Drag and reposition the shape points to add curvature to the link. To delete Poly Points, you can do this several ways: 1. Left-click to highlight a Poly Point and use the Delete key on your keyboard. 2. Right-click on a Poly Point and select either 



Delete Poly Point or Delete All Poly Points on Link (this will reset the geometry to a straight link between the two connected intersections)



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Network Building



Delete Link: this will delete the connection between the two intersections while retaining the legs independently, including all defined Poly Points.

Hint: You can also delete the Link by using the Delete key on your keyboard. 

7.4

Delete Link and Legs: this will delete the connection between the two intersections and the Legs that were connected, removing these as approach legs from each of the intersections.

Add Zones to Represent your Development Sites

Vistro Zones are objects used to represent development sites. These must be added to your network to provide the basis for Trip Generation, Distribution, and Assignment. Similar to intersections, you can add zones to your network using the Toolbar or the Context Menu, as described below.

Using the Toolbar 1. Select the icon from the toolbar. 2. Left-click over the network window to place the zone in the correct location.

Using Context Menu 1. Right-click in the network window (this will open a context menu).

2. Select Insert Zone by left-clicking the list option. 3. Reposition the Zone(s) as needed by left-clicking and dragging to the proper location You can delete a Zone as follows: 1. Left-click or hover over the zone/gate to select it (highlighted blue). 2. Right-click and select Delete Zone/ Delete Gate from the context menu; or press Delete on the keyboard.

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7.5

Add Gates for Routing of Development Traffic

In Vistro, traffic for development Zones is routed to and from traffic “Gates”. These objects can be placed anywhere in your network and represent the areas where traffic flows to and from the development Zones.

Using the Toolbar 1. Select the icon from the toolbar. 2. Left-click over the network window to place the Gate in the correct location.

Using Context Menu 1. Right-click in the network window. This will open a context menu:

2. Select Insert Gate by left-clicking the list option. 3. Reposition the Gate(s) as needed by left-clicking and dragging to the proper location. You can delete a Gate as follows: 1. Left-click or hover over the zone/gate to select it (highlighted blue). 2. Right-click and select Delete Gate from the context menu; or press Delete on the keyboard.

7.6

Define Paths for Assigning Development Traffic to your Street Network

Zones and Gates are not physically connected to the network by links. Paths are drawn to connect Zones and Gates throughout the network, which allows for the assignments of new trips between Zones and Gates and along the network. Paths from a Zone to a Gate (outbound paths) are drawn by selecting the Path tool and then clicking on a Zone and all intermediate intersections and finally clicking the destination Gate. Similarly, paths from a Gate to a Zone (inbound trips) are drawn by clicking on the Gate first, then all intermediate intersections and finally clicking the destination Zone. Once defined,

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Network Building

paths can be selected in the Trip Assignment workflow table and the selected path is displayed graphically in the network window. To add a path, do the following: 1. Select the Path

icon from the Toolbar.

2. In the network window, click on the Zone or Gate to start the Path. 3. Click at the end of the link where the path will enter the street network. 4. Click on the next intersection in sequence to include in the Path. 5. Continue clicking on each intersection to include in the Path. 6. Click at the end of the link where the Path will enter the street network. 7. Click on the Zone or Gate to end the Path. Once a Path is created, select the path in the table and right-click for the following options: 



Delete Path – completely delete the path from the network Create Reverse Path – create the path using the same nodes and links but in the opposite travel direction from the selected Path

7.7

Translating Networks

Networks can be moved in their entirety to other positions on the background map by performing three steps: 1. Right-click on one of the intersections in the network to open the context menu.

2. Select Map this Point to Background Position from the context menu. 3. Left-click on the position in the background map where you want that intersection to move to. The network is then moved to the new position, correctly maintaining the relative distances in the network.

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Base Model Development

8


Now that the network structure is complete, you can enter the necessary data to complete your model and analyze the operations. In Vistro, this process is organized into three easy Base Workflow data entry steps: 1. Intersection Setup: contains all physical information for each intersection 2. Volumes: Input Base volumes, volume adjustments, growth rates, and developmentrelated volumes 3. Traffic Control: enter all traffic control data based on the control type and methodology After completing these three steps, your network is complete and ready for reporting. The data tables can be accessed by toggling the appropriate Workflow step in the Workflow Panel.

8.1

Intersection Setup (Geometry)

The first step in the Workflow is to define the geometric and physical parameters of each intersection in the Intersection Setup. The table parameters automatically change based on the defined intersection control type and methodology so you enter only the required data. Some of the parameters are dependent on a parent parameter or are calculated based on other entries. These dependent parameters are greyed out until the parent parameter is defined.

8.1.1

Common Parameters and Unknown Control Type

Every intersection setup table includes common parameters, including the intersection number, name, control type, approach name, approach direction, turning movement, base volume input, and the total analysis volume (Figure 2: Intersection Setup: Unknown Control Type Common Parameters Table). Once the control type and methodology are defined, the parameters relevant to that combination are displayed. The common parameters displayed below are also the default attributes for the Unknown control type definition (Table 2: Intersection Setup: Common ) .

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Figure 2: Intersection Setup: Unknown Control Type Common Parameters Table

Table 2: Intersection Setup: Common Intersection Setup Parameters Parameter

Description

Units

Number

Unique number of the intersection. Intersections are numbered consecutively, however the preset number may be overwritten by another number that does not already exist in the network.

n/a

Intersection

Name of Intersection

n/a

Control Type

Intersection control type [Options: Unknown, Signalized, Roundabout, All-way Stop, Two-way Stop]

n/a

Name

Name of Approach

n/a

Show Name

If checked, the text entered in the Name field will be shown in the network window when the Show Street Names graphics selector is active.

n/a

Direction of Approach. Eight approaches possible [NB, SB, EB, WB, NW, NE, SW, SE]

n/a

Lane Configuration

Graphical selector and representation of the lane configuration for each approach described below

n/a

Turning Movement

Direction of turning movement. When there are more than 4 legs it is possible to have more than one left or right turn for a particular movement. In this case the adjacent turn movement will be appended with the number 2. For example, an approach to 5 other legs may show Left2, Left, Thru, Right, Right2.

n/a

Base Volume Input

Base traffic volume input by user. Base volume may be entered in either the intersection setup table or the volume table.

Veh/h

Total Analysis Volume

Calculated total analysis volume. The total analysis volume includes all volume adjustments defined and site development trips if present (see Section 8.2 Volumes on page 61 for a detailed description of volume parameters).

Veh/h

Crosswalk

Crosswalk selection for approach

n/a

Approach

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8.1.1.1

Lane Configuration

Vistro offers a graphical lane configuration window with pre-defined templates and full flexibility to define your specific lane configuration. To define your Lane Configuration for an approach: 1. In any table in the Basic Network Workflow Tabs, double-click on the Lane Configuration to bring up the dialog for that specific approach. 2. Click on the lane(s) to define the Lane Configuration. 3. Click outside of the Lane Configuration dialogue to exit and save. 4. To cancel , click the “x”. The Lane Configuration dialog is shown below. Figure 3. Lane Configuration Dialog

Here, you will find pre-defined templates and all movement arrows for the approach based on the total number of approaches at the selected intersection. You can define the lane configuration in two ways:

Select an approach template Simply click on any of the templates in the window to highlight it in green.

Select by Individual Movement and Arrow To see all movement arrow possibilities for the approach, click on the “ +” sign in the dialog:

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Here, you can add or subtract specific movement arrows by hovering over the arrow and clicking on the green “ +” or red “ -“buttons. As you change this, you will see the number of lanes associated with that movement arrow currently defined for the approach.

As you select the desired movement arrows, other movement arrows will become unavailable if they conflict with the current selection.

8.1.2

Signalized Intersection Setup

The Intersection Setup table for signalized intersections is shown in Figure 4: Intersection Setup: Signalized Intersection Table.

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Figure 4: Intersection Setup: Signalized Intersection Table

The intersection setup table for the signalized control type includes all of the common parameters (Table 2: Intersection Setup: Common ) listed for the unknown control type, plus the parameters listed in Table 3: Intersection Setup: Signalized Intersection Setup Parameters. Table 3 also lists for each parameter if applicable, units, default values, value ranges, relevant signalized methodology (HCM 2010, HCM 2000, ICU, Circular 212), and ANM indicator if the parameter is used when exporting to Vissim. Table 3: Intersection Setup: Signalized Intersection Setup Parameters Parameter

Description

Units 0

0 0

0

0

1 2

Analysis Method

U 2

2

M 2

A

N 1

CI

Intersection capacity analysis methodology for selected intersection based on control type. Signalized options: HCM 2010, ICU 1, ICU 2, Circular 212 Planning, Circular 212 Operations, HCM 2000

Lane Width

Width of the travel lane

ft or m

x

x

x

x

x

Default = 12 ft (3.7 m), Range = any number

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No. of Lanes in Pocket

Defines how many lanes of the approach geometry are pocket lanes. A pocket lane is a lane added on the approach of an intersection. Pocket lanes are most commonly used for turning movements, but may be used for through movements as well. The pocket lanes are always defined to either the left or right of the through movement. For the example case of a two-lane road with the approach lane geometry of a 1 -Left, 2-Thru, 1-Right, there would be 1 pocket lane defined e ach for the left and right lanes. In a more complex example, a two-lane ro ad with the approach lane geometry of 1-Left, 3-Thru, 1-Right, there would be 1 pocket lane for the left and 2 pocket lanes to the right.

x

x

x

x

x

x

x

Default = 0; Range = 0 – [# turn+through lanes – 1] Pocket Length

Length of the respective pocket lane(s)

Median

A checked box defines a center median for the approach. A median is a dividing separation between opposing directions on an approach.

Median Length

Length of the median for the selected approach measured upstream from the stop bar location.

ft or m

x

Default = 0; Range = 0 – approach link length x

ft or m

x

ft or m

x

Default = 0; Range = 0 – approach link length Median width

Width of median for selected approach Default = 0; Range = 0 – any real number

Speed

Grade

Speed of selected approach

x

x

x

Default = 30 mph (48.3 km/h); Range = 1 - 255

mph or km/h

Grade (slope) of the selected approach

%

x

x

x

x

x

x

Default = 0; Range = 0.00 – 100.00 Crosswalk

A checked box defines a crosswalk on the selected approach

Crosswalk Width

Width of the crosswalk. This parameter is used if exporting to Vissim. In Vissim the crosswalks are modeled using two opposing links, so each link has h alf the width of the full crosswalk width. A crosswalk with of 5 ft will generate a 10 ft crosswalk after exporting to Vissim.

ft or m

x

Default = 6 ft (1.8 m) Range = 0 – any real number Channelized

A checked box defines a channelized right turn lane (left turn for left-hand model) for the approach.

x

Channelized Control

For a channelized turn lane, defines the control for entering the mainline traffic.

x

Options: SC (Signal Control), Stop, Yield, Target Lane (free) Channelized Radius

Radius of the c hannelized turn that tangentially approximates to the outer boundary of the two approaches of the turn movement.

ft or m

x

Default = 20 ft. Range = 0 – approach link length Right Turn on A checked box turns on right turn on red (RTOR) for right turn Red movement (left turn for left-hand model).

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8.1.3

Roundabout Intersection Setup

The Intersection Setup table for roundabout intersections is shown in Figure 5: Intersection Setup: Roundabout Intersection Setup Table. Figure 5: Intersection Setup: Roundabout Intersection Setup Table

The intersection setup table for the roundabout control type includes all of the common parameters listed for the unknown control type, plus the parameters listed in Table 4: Intersection Setup: Roundabout Intersection Setup Parameters. Table 4: Intersection Setup: Roundabout Intersection Setup Parameters also lists for each parameter if applicable, units, default values, value ranges, relevant roundabout methodology (HCM 2010 or Kimber), and ANM if the parameter is used when exporting to Vissim. Some of the geometry parameters for the Kimber methodology have a letter reference (i.e. (D)) at the beginning of their description referring to parameter reference in Figure 6: Description of the Node Geometry for the Kimber model.

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Table 4: Intersection Setup: Roundabout Intersection Setup Parameters Parameter

Description

Units R E B 0

M

1 MI 0 2

Analysis Method

Lane Width

N K

A

Intersection capacity analysis methodology for selected intersection and control type. If a global analysis methodology is defined under the global parameters dialog, then the analysis method in the intersection setup table does not apply. [Roundabout options: HCM 2010, Kimber] Width of the travel lane

ft or m

x

x

x

x

x

x

Default = 12 ft (3.7 m), Range = any real number No. of Lanes in Pocket

Defines how many lanes of the approach geometry are pocket lanes. A pocket lane is a lane added on the approach of an intersection. Pocket lanes are most commonly used for turning movements, but may be used for through movements as well. The pocket lanes are always defined to either the left or right of the through movement. For the example case of a two-lane road with the approach lane geometry of a 1-Left, 2-Thru, 1-Right, there would be 1 pocket lane defined each for the left and right lanes. In a more complex example, a two-lane road with the approach lane geometry of 1-Left, 3-Thru, 1-Right, there would be 1 pocket lane for the left and 2 pocket lanes to the right. Default = 0; Range = 0 – [# turn+through lanes – 1]

Pocket Length


Speed

Speed of selected approach

Grade

ft or m

x

Default = 0; Range = 0 – approach link length x

x

x

Default = 30 mph (48.3 km/h); Range = 1 - 255

mph or km/h


%

x

x

x



Crosswalk Width

Width of the crosswalk. This parameter is used if exporting to Vissim. In Vissim the crosswalks are modeled using two opposing links, so each link has half the width of the full crosswalk width. A crosswalk with of 5 ft will generate a 10 ft crosswalk after exporting to Vissim.

x ft or m

x

Default = 6 ft (1.8 m) Range = 0 – any real number Crosswalk Setback

Distance of the crosswalk setback from the line of s ight on the approach.

ft or m

Default = 0; Range = 0 – 300 ft (91.4m) Bypass Lane

A checked box defines a channelized right turn lane (left turn for left-hand model) for the approach.

x

Bypass Control

For a channelized turn lane, defines the control for entering the mainline

x

Default = Yield; Options: Without, Stop, Yield, Target Lane (free)

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Bypass Radius

Radius of the bypass turn lane that tangentially approximates to the outer boundary of the two approaches of the turn movement.

ft or m

Default = 20 ft; Range = 0 – approach link length Entry Lane Width

(E) Width of the approach directly at entry ac ross all lanes.

Entry Radius

(R) Radius of the entry on the specified approach. More specifically the radius which tangentially approximates to the outer circle of the roundabout and the outer boundary of the approach.

ft or m

x

x

ft or m

x

x

degrees

x

x

ft or m

x

x

ft or m

x

x

ft or m

x

x

Default = sum of the approach lane widths.

Default = 50 ft (15.2 m); Range = 0 - 500 ft (152.4 m) Entry Angle

(Φ) See Figure 6: Description of the Node Geometry for the Kimber model Default = 45 degrees; Range = 0 – 180 degrees

Approach Half Width Flare Length

(V) Road width of the approach without any turn pockets. Default = 10 ft (3.1 m); Range = 5 - 50 ft (1.5 - 15.2 m) (L‘) Half of the Length of the approach segment between the points where Entry Lane Width and Approach Half Width are measured. Default = 60 ft (18.3 m); Range = 3 – 60 ft (0.9 – 18.3 m)

Grade Separation

(SEP) Distance between approach and exit of the same node leg. For regular roundabouts specify 0 ft. With values > 0 you describe the approaches at expanded roundabouts where the ap proach is far away from the exit of the same leg. Default = 0; Range = 0 - 300 ft (91.4 m)

No. of Circulating Lanes

Number of lanes in the circle that conflict with the entry.

No. of Exit Lanes

Number of exit lanes on the specified approach.

Exit Lane Width

Width of the exit lane on the specified approach. If there is more than one exit lane, then each lane will use this value.

x

x

x

ft or m

x

Default = 12.0 ft (3.66 m); Range = 8 – 60 ft (2.4 – 18.3 m) Exit Radius

Radius of the exit on the specified approach.

ft or m

x

x

Default = 50 ft (15.2 m); Range = 3 – 500 ft (0.9 – 152.4 m) Inscribed Circle Diameter

(D) External diameter of the roundabout. For asymmetric roundabouts specify the radius related to the environment of the specified approach.

ft or m

Default = 75ft; Range = 32.8 – 656.2 ft (10 – 200 m) Circulatory Roadway Width

Width of the circulatory roadway.

Splitter Island

A checked box defined presence of a splitter island for the selected approach.

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ft or m

x

Default = sum of lane width for the approach; Range = 3 – 500 ft (0.9 – 152.4 m) x

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Splitter Island Length

Length of the Splitter Island measured from the outside boundary of the circle.

ft or m

x

x

Default = 0; Range = 0 – approach link length Splitter Island Width

Width of splitter island at the outside boundary of the circle.

ft or m

x

Default = 0; Range = any real number

Figure 6: Description of the Node Geometry for the Kimber model

8.1.4

Two-way Stop and All-way Stop Intersection Setup

The Intersection Setup table for signalized intersections is shown in Figure 7: Intersection Setup: Two-way & All-way Stop Intersection Setup Tables.

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Figure 7: Intersection Setup: Two-way & All-way Stop Intersection Setup Tables

The intersection setup tables for the all-way and two-way stop control types include all of the common parameters listed for the unknown control type, plus the parameters listed in Table 5: Intersection Setup: Two-way & All-way Stop Intersection Setup Parameters. Table 5: Intersection Setup: Two-way & All-way Stop Intersection Setup Parameters also lists for each parameter if applicable, units, default values, value ranges, relevant unsignalized methodology (HCM 2010 or HCM 2000), and ANM if the parameter is used when exporting to Vissim. Table 5: Intersection Setup: Two-way & All-way Stop Intersection Setup Parameters Parameter

Description

Units 0

0 0

0 2

Analysis Method

Lane Width

1

M 2

A

0

N

Intersection capacity analysis methodology for se lected intersection based on control type. If a global analysis methodology is defined under the global parameters dialog, then the analysis method in the intersection setup table does not apply. [All-way & Two-way Stop options: HCM 2010, HCM 2000] Width of the travel lane

ft or m

x

x

x

Default = 12 ft (3.7 m), Range = any number

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No. of Lanes in Pocket

Defines how many lanes of the approach geometry are pocket lanes. A pocket lane is a lane added on the approach of an intersection. Pocket lanes are most commonly used for turning movements, but may be used for through movements as well. The pocket lanes are always defined to either the left or right of the through movement. For the example case of a two-lane road with the approach lane geometry of a 1-Left, 2-Thru, 1-Right, there would be 1 pocket lane defined each for the left and right lanes. In a more complex example, a two-lane road with the approach lane geometry of 1 -Left, 3-Thru, 1-Right, there would be 1 pocket lane for the le ft and 2 pocket lanes to the right.

x

x

x

x

x

x

Default = 0; Range = 0 – [# turn+through lanes – 1] Pocket Length


ft or m

Default = 0; Range = 0 – approach link length Median

A checked box defines a center median for the approach. A median is a dividing separation between opposing directions on an approach.

Median Length

Length of the median for the selected approach measured upstream from the stop bar location.

x

ft or m

x

ft or m

x

mph or km/h

x

Default = 0; Range = 0 – approach link length Median width

Width of median for selected approach Default = 0; Range = 0 – any real number

Speed

Speed of selected approach Default = 30 mph (48.3 km/h); Range = 1 - 255

Grade


%

x

x

x



Crosswalk Width

Width of the crosswalk. This parameter is used if exporting to Vissim. In Vissim the crosswalks are modeled using two opposing links, so each link has half the width of the full crosswalk width. A crosswalk with of 5 ft will generate a 10 ft c rosswalk after exporting to Vissim.

x ft or m

x

Default = 6 ft (1.8 m) Range = 0 – any real number Channelized

A checked box defines a channelized right turn lane (left turn for lefthand model) for the approach.

x

Channelized Control

For a channelized turn lane, defines the control for entering the mainline traffic.

x

Options: SC (Signal Control), Stop, Yield, Target Lane (free) Channelized Radius

Radius of the channelized turn that tangentially approximates to the outer boundary of the two approaches of the turn movement.

ft or m

x

Default = 20ft; Range = 0 – approach link length

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8.2

Volumes

One of Vistro’s most powerful features is its trip accounting capability. With Vistro there are multiple layers of volumes and adjustments that can be entered to result in the desired analysis volume. When performing a traffic impact analysis (TIA) in Vistro, trips associated with a development are automatically calculated for each turn movement in the network once the trip generation, distribution, and assignment have been performed. Additionally, Vistro provides place holders to make volume adjustments, such as in-process trips from an already approved, but not yet built development that needs to be included in the analysis. In the case of a non-TIA project, all of the TIA-related parameters are grouped together and can be collapsed in the volume setup table by using the arrow button to the left of the TIA Demand header. Parameters that appear italicized in the volume setup table are calculated values. The Volumes workflow task table is shown in Figure 8: Volumes Table. All parameters in the volume setup table are described below in Table 6: Volumes Parameters. Figure 8: Volumes Table

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Table 6: Volumes Parameters Parameter

Description

Units Basic Volume Inputs

Number

Unique number of the intersection. Intersections are numbered consecutively, however the preset number may be overwritten by another number that does not already exist in the network.

Intersection

Name of Intersection

Approach

Direction of approach as defined under the intersection setup table.

Lane Configuration

Shows lane configuration as defined in intersection setup table.

Turning Movement

Identifies the movement (Left, Thru, Right, U-Turn)

Base Volume Input

Summary of Base Volume Input, description below.

veh/h

Total Analysis Volume

Summary of Total Analysis Volume, description below

veh/h

Base Volume Input

Base traffic volume input by user.

veh/h

Base Volume Adjustment factor

User definable adjustment factor to apply if desired to base volume input. An example application would be a seasonal adjustment factor. Default = 1.0000; Range = 0 - 99.9000

Final Base Volume

Base volume representing the base condition.

veh/h

= Base Volume Input * Base Volume Adjustment Factor Heavy Vehicles Percentage

Percent of heavy vehicles for each turn movement.

Growth Rate

Growth rate to be applied as multiplicative factor to adjust volume to future year analysis.

Default = 2; Range = 0 – 100

Default = 1.000; TIA Demand In-Process Volume

User definable volume input typically used to account for trips already approved by a nearby development that is not yet in place.

veh/h

Future Background Volume

Future volumes before any trips are added for the new development.

veh/h

= Final Base Volume * Growth Rate + In-Process Volume

Site-Generated Trips Trips calculated from the new development(s) based on the trip generation, distribution, and assignment paths. Making changes to any component of the trip generation process will result in a change to this value.

veh/h

Diverted Trips

Trips attracted from the traffic on roadways within the vicinity of the development site but require a diversion from that roadway to another roadway to gain access to the site. Diverted trips add traffic to the roadways adjacent to a site. Value may be negative or positive.

veh/h

Pass-by Trips

Trips made as intermediate stops to the development on the way from an origin to a primary trip destination. This field is used in tandem with the Trip Generation for a zone. Primary trips (non-passby) can be generated and assigned to the study network, while pass-by adjustments at project driveways can be entered in these fields. Value may be negative or positive.

veh/h

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Existing Site Adjustment Volume

Net New Trips

User defined volume adjustment to account for trips either added or removed due to changes in the land use to accommodate the new development. For example, an existing apartment complex is removed to allow construction of a new retail shop. In this case, trips from the apartment complex have been accounted for in the base volume and now need to be removed. This parameter may be positive or negative.

veh/h

Total new trips added to the system after accounting for all adjustments.

veh/h

= Site Generated + Diverted + Pass-by + Existing Site Adjustment Volume Additional Volume Adjustments and Calculations Other Volume

User definable volume not accounted for by other volume parameters

veh/h

Future Total Volume

Total future volume after all site generated trips and volume adjustments have been made.

veh/h

= Future Background Volume + Net New Trips + other volume Right-Turn on Red Volume

Volume adjustment to account for vehicles per hour that turn right on a red signal. Value is positive.

veh/h

Total Hourly Volume

Total hourly future volume after accounting for right-turn on red

veh/h

Peak Hour Factor

PHF based on the Highway Capacity Manual used to adjust the hourly volume to reflect the 15-minute peak flow rate. Default = 1.0000; Range = 1 – 1.0000

Other Adjustment Factor

User defined adjustment factor to account for factors not accounted for by any other parameter. Default = 1.0000; Range = 1 – 99.9000

Total 15-Minute Volume

Estimated total vehicles during the highest 15-minute period of the peak hour.

vehicles

= (Total Hourly Volume * 0.25 / PHF) * Other Adjustment Factor Total Analysis Volume

Calculated total analysis volume, including all volume adjustments and factors defined.

veh/h

= Total 15-Minute Volume * 4 Presence of OnStreet Parking

Checkbox to indicate on-street parking is present and a factor in the analysis

On-Street Parking Maneuver Rate

Number of on-street parking maneuvers per hour that occur on the approach adjacent to the movement indicated

#/h

Local Bus Stopping Rate

Number of bus stop maneuvers per hour that occur on the approach

#/h

Pedestrian Volume

Pedestrian volume on crosswalk of selected approach. This volume is utilized in the HCM calculation and to generate pedestrian input for crosswalks when exporting to Vissim

Peds/h

Bicycle Volume

Bicycle volume crossing selected approach as similar to the pedestrian crossing(signalized intersections only).

Bicycles/h

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8.3

Traffic Control

This section of the manual provides a listing of all of the traffic control parameters and their definitions. The traffic control input tables are unique to each control type and the specified methodology. Some parameters are inputs, whereas others are calculated values. Calculated values in italics are not editable. Some calculated parameters may be overridden by the user. A full description of the methodologies can be found in Analysis Methods on page 154.

8.3.1

Signalized Traffic Control

The traffic control workflow tables are presented for each of the signalized intersection analysis methods, including HCM 2010, HCM 2000, Circular 212 and ICU.

8.3.1.1

HCM 2010 and HCM 2000 for Signalized Intersections

The Traffic Control table for the HCM 2010 and HCM 2000 methods for signals is shown in Figure 9: Traffic Control Table: HCM 2010 and HCM 2000 for Signalized Intersections . Table definitions are presented in Table 7: Traffic Control Parameters: HCM 2010 and HCM 2000 for Signalized Intersections. Figure 9: Traffic Control Table: HCM 2010 and HCM 2000 f or Signalized Intersections

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Table 7: Traffic Control Parameters: HCM 2010 and HCM 2000 for Signalized Intersections Parameter

Description

Units Intersection Settings

Analyze Intersection? Analysis Period

Located in CBD

Controller ID

A check box indicates this intersection will be included in the analysis and reports.

Time period for the analysis, either 15 min or 1 hr A check box indicates the intersection is in a central business district. When active sets the area type (saturation flow) adjustment factor to 0.90. See HCM for description of CBD area. Each signal controller has a unique ID number. This value defaults to the intersection number, but can be changed for intersections that are controlled by a controller common to another intersection.

Signal Coordination Signalized intersections of the same sub group are coordinated collectively. Group Multiple sub groups (coordinated routes) are permitted. Cycle Length

Controller cycle length. This is the maximum time it will take for each signal group to cycle once. The cycle length is only used for coordination.

Coordination Type

Defines coordination as Free, Time of Day Pattern Coordinated, or Time of Day Pattern Isolated.

Actuation Type

Offset

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S

Defines whether the controller operates as fixed time, fully actuated or semiactuated. When coordinated, the local cycle timer will be offset from the master cycle timer by the defined offset time relative to the reference point.

S

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This is the point in the cycle where the master cycle timer will be equal to the defined Offset time when the controller is coordinated and not in transition (offset seeking). The selections are: 

LagFO (Lagging Force-Off) – The reference point will be at the force -off point for the lagging coordinated signal group.



LeadGreen (Leading Start of Green) – The reference point will be at the start of the leading coordinated signal group green (the computed start of green, note that the signal group may actually return to g reen early if there is lack of demand on opposing movements).



LagEnd (End of Lagging Red) – The reference point will be at the end of Red Clear for the lagging coordinated signal group.



Offset Reference

CoordEnd (End of Coordinated Group Red) – The reference point will be at the end of red for the last signal group in the concurrent barrier group with the coordinated signal groups.

Figure 10: Coordination Offset Reference Modes

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This setting defines the permissive mode for the coordination pattern. The permissive mode controls the method in which permissive periods are opened and closed for all non-coor dinated signal groups. The controller will only yield to signal groups that are permissive following the end of green on each coordinated signal group. The permissive modes are as follows: 

SingleBand – The permissive period for non-coordinated signal groups will open: At the beginning of the coordinated signal group green for signal groups in the same ring and concurrent barrier group as the coordinated signal group, or At the beginning of the lagging coordinated signal group green for signal groups outside of the same concurrent barrier group as the coordinated signal groups. The permissive period for non-coordinated signal groups will close: When there is no longer enough time to clear all timing signal groups and serve the longer of the Minimum Green or Permissive Green on the signal group, or When the signal group is in a different concurrent barrier group then the

Permissive Mode

coordinated signal groups and any coordinated signal group has yielded to a signal group that is sequentially before the coordinated signal g roup, in the same ring and concurrent barrier group (i.e. a lagging coordinated signal group yielding to its opposing left turn will close all c ross street permissive periods for the remainder of the cycle). 

MultiBand – The permissive period for non-coordinated signal groups will open: The same as Single Band Permissive operation above, but only for the first signal group in each ring that sequentially follows the coordinated signal group. For each subsequent signal group, the permissive period will open once the previous signal group’s permissive period closes (Only one signal group per ring can be permissive at any given time). The permissive period for non-coordinated signal groups will close the same as they do for Single Band Permissive operation above.



Reservice – The permissive mode will operate the same as Single Band Permissives until the coordinated signal groups yield to a non-c oordinated movement. ALL signal groups will be allowed to reserve. After the coordinated signal groups yield once:

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

Signal Groups in the non-coordinated barrier group will be allowed to reserve if there is enough time to serve the minimum green time (or minimum permissive green time if greater than minimum green time) and still be able to have the leading coordinated signal group green by the start of its split:



Signal Groups in the coordinated barrier group will be allowed to reserve if there is enough time to serve the minimum green time (or minimum permissive green time if greater than minimum green time) and still be able to have the coordinated signal group in the same ring green by the start of its split.

Figure 11. Permissive Modes Coordination

Permissive Mode

(continued)

Lost Time

Total time per cycle not effectively being used due to driver reaction time, acceleration, and deceleration at the start and end of active s ignal groups. This is S typically three to four seconds per signal group, times the number of signal groups. Phasing and Timing

Control Type Allow Lead/Lag Optimization Signal Group

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Defines control of movements as: permissive; protected; protected / permissive; split; overlap. Checkbox to allow for lead/lag optimization.

The signal group is the signal phase number.

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Auxiliary Signal Groups

All signal groups serving the movement. When the Control Type is “Overlap” and the Signal Group for the Overlap phase is entered, the Auxiliary Signal Groups cell is active and allows selections of any phases with which this movement overlaps.

Lead/Lag

Selection for Lead or Lag left turn for protected phasing.

Minimum Green

Minimum green time that the signal group will serve before changing to yellow.

Maximum Green

S

Maximum time that the signal group will be allowed to extend before it will max-o ut. A max-out will make a signal group eligible to terminate, even though it may not S have gapped-out. This parameter when exported to RBC is reflected as Max1.

Amber

Time a signal group will time an amber interval before advancing to red.

S

All red

Time a signal group will time red before a c onflicting signal group will be allowed to S begin timing.

Split

Amount of time allocated in the cycle for each signal group to time. The split includes the time it will take the green, yellow, and red intervals to time for each signal group. The split should at least accommodate the signal group Min Green plus Yellow Clearance plus Red Clearance time, but it does not necessarily n eed to accommodate the full pedestrian service time for an actuated pedestrian sign al group. The sum of the splits of all signal groups in each ring should add up to the Cycle Length.

Vehicle Extension

Allowed time between successful vehicle extensions before a signal group will gap out. This parameter may be referred to as passage in some controllers and does S not affect the capacity c alculation.

S

Walk

Minimum time a signal group will display a walk indication before advancing to the pedestrian clearance interval (flashing don’t walk). A signal group may not advance S to yellow while the pedestrian movement is in the walk interval.


Time a signal group will display a flashing don’t walk indication before advancing to solid don’t walk. A signal group may not advance to Yellow while the pedestrian S movement is in the pedestrian clearance interval.

l1, Start-Up Lost Time

Additional time needed to react to the initiation of the green signal and then accelerate.

S

l2, Clearance Lost Time

Time between signal indication changes during which the intersection is not used by vehicles.

Coordinated

Identifies the coordinate signal groups for the signal controller.

Minimum Recall

Signal groups flagged for this option will receive an automatic vehicle call regardless of actuation and time for at least its minimum green time. The green time may extend beyond the minimum if demand is present.

Maximum Recall

Signal groups flagged for this option will receive an a utomatic vehicle call and extension. The maximum green timer will unconditionally begin timing at the beginning of green. Normally, the maximum green timer will only time if there are opposing calls to the signal group.

Pedestrian Recall

Signal groups flagged for this option will receive an automatic pedestrian call and time for the full walk plus pedestrian clearance time.

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S

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Dual Entry

When a signal group has a call in the next barrier group, concurrent phases in that barrier group may not have a call. In such case both the signal group with the call and the signal group with no call will begin timing when the barrier is crossed if both signal groups are flagged with Dual Entry. This feature is o ften used for S through movement signal groups such that if one signal group i s called, the signal group in the opposite direction will automatically serve, even if it does not have a call.

Detector

Checkbox to choose detector.

Detector Location

Distance upstream of stop bar of leading edge of detector.

ft / m

Detector Length

Length of detector.

ft / m

I, Upstream Filtering Factor

Adjustment factor to account for the effect of an upstream signal on vehicle arrivals to the subject movement group. This is currently user -defined. Exclusive Pedestrian Phase

Pedestrian Signal Group

The signal phase number for the exclusive pedestrian phase.

Pedestrian Walk

Minimum time the exclusive pedestrian signal group will display a walk indication before advancing to the pedestrian clearance interval (flashing don’t walk). A signal S group may not advance to yellow while the pedestrian movement is in the walk interval.


Time the exclusive pedestrian signal group will display a flashing don’t walk indication before advancing to solid don’t walk. A signal group may not advance to S Yellow while the pedestrian movement is in the pedestrian clearance interval. Lane Group Calculations

Lane Group

Lane or group of lanes designated for analysis

Control Type

Defines control of movements as: permissive; protected; protected / permissive; split; overlap.

C, Cycle Length

Controller cycle length. This is the maximum time it will take for each signal group to cycle once. The cycle l ength is only used for coordination.

L, Total Loss Time per Cycle

Total lost time per cycle for specified lane group.

l1, Start Up Loss Time

Time consumed to react and begin acceleration after signal group initiates green. Default = 2.0s

l2, Clearance Loss Time

s

s

Time consumed at the end of a signal group not serving traffic due to drivers decelerating and stopping in reaction to an amber indication.

s

s

Default = 3.0s

Green Time Start

Start of the signal group green time in the local cycle.

s

Green Time End

End of the signal group green time in the local cycle.

s

G, Actual Green Time

Displayed green time per cycle.

s

g_i, Effective Green Amount of green time where vehicles proceed at the saturation flow rate. Time

s

g/C, Green / Cycle

s

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The ratio of the effective green time of a signal group to the cycle length.

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(v/s)_i, Volume / Saturation Flow Rate

The ratio of the volume to the saturation flow rate for the specified lane group. veh/h

Critical Lane Group Lane groups with the highest flow rate are indicated as critical. Saturation Flow Calculations Lane Group


Control Type


so, Base Saturation Saturation flow rate for base (ideal) conditions Flow Rate Default = 1900 veh/h/ln N, Number of Lanes f_w, Lane Width Adjustment

veh/h/ln

Number of lanes in the lane group

Factor for lane width adjustment

f_HV, HGV Adjustment

Adjustment factor for heavy vehicles

f_g , Grade Adjustment

Adjustment factor for the approach grade

f_p, Parking Adjustment

Adjustment factor for parking operations adjacent to travel lane

f_bb, Bus Blocking Adjustment factor for bus periodically blocking travel lane at transit stop Adjustment f_a, Area Type Adjustment

Adjustment factor for CBD designation

f_LU, Lane Utilization Adjustment

Adjustment factor for non-balanced lane utilization

Override Calculated Checkbox to activate user input for Lane Utilization Adjustment Factor Lane Utilization Adj f_LU,u, Userdefined Lane Utilization Adjustment

User-defined Lane Utilization Adjustment Factor. When this is defined, this value will be used in place of the calculated f_LU.

p_LT, Proportion Left Turns

Proportion of left-turning vehicles in the lane

p_RT, Proportion Right Turns

Proportion of right-turning vehicles in the lane

f_LT, Left Turn Adjustment

Adjustment factor to reflect left-turn geometry

f_RT, Right Turn Adjustment

Adjustment factor to reflect right-turn geometry

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%

%

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f_Lpb, Left Turn Pedestrian Adjustment

Pedestrian adjustment factor for left-turn groups

f_Rpb, Right Turn Pedestrian Adjustment

Pedestrian adjustment factor for right-turn groups

Total Saturation Flow Adjustment

Aggregated adjustment factor; the product of the various saturation flow adjustments.

s , Calculated Final Calculated final saturation flow rate after all adjustments have been taken into Saturation Flow account. Rate

veh/h/ln

Override Calculated Checkbox to activate user input for Saturation Flow Rate Saturation Flow Rate User-Defined Saturation Flow Rate Arrival Type

User-defined Saturation Flow Rate. When this is defined, this value will be used in place of the Calculated Final Saturation Flow Rate

veh/h/ln

Level of platooning in traffic arriving at the selected approach. Default = 3; Range = 1 – 6 (very poor – exceptional coordination) Capacity Analysis

Lane Group


Control Type


V, Volume

Lane group volume (total analysis volume)

s, Saturation Flow Rate

Final saturated flow rate (calculated or user-defined )

c, Capacity

Effective capacity, taking into account all opposing flows etc.

g/C, Green / Cycle

The ratio of the effective green time of a signal group to the cycle length

X, Volume / Capacity

The ratio of the total analysis volume (flow rate) to the ca pacity

d1, Uniform Delay

veh/h veh/h veh/h

The first term of the equation for lane group control delay, assuming constant arrival and departure rates during a given time period. (1)

s

k, incremental delay Incremental delay factor used to account for the effect of controller type on delay. calibration factor Default = 0.50

d2, Incremental Delay,

The second term of lane group control delay, accounting for delay due to the effect of random, cycle-by-cycle fluctuations in demand that occasionally exceed capacity s (i.e., cycle failure) and delay due to sustained oversaturation during the analysis period. (1)

d3, Initial Queue Delay

The third term of lane group control delay, accounting for delay due to a residual queue identified in a previous analysis period and persisting at the start of the s current analysis period. This delay results from the additional time required to clear the initial queue. (1)

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Rp, Platoon Ratio

Describes the quality of signal progression for the corresponding movement group. Values based on HCM look-up table for arrival type.

P, Proportion Arriving on Green

Proportion of vehicles arriving during the green indication

PF, Progression Factor

Delay adjustment factor based on the progression quality

%

Lane Group Results X, Volume/Capacity The ratio of the total analysis volume (flow rate) to the capacity for Lane Group d, Delay for Lane Group

Control delay for lane group

Lane Group LOS

Level-of-service for lane group

s/veh

Critical Lane Group Lane groups with the highest highest flow rate are indicated indicated as critical. 50th-Percentile Queue Length

50th percentile queue length measured in number of vehicles

50th-Percentile Queue Length

50th percentile queue length measured in feet





veh

ft

veh

ft

Movement, Approach, & Intersection Results d_M, Delay for Movement

Control delay per movement

Movement LOS

Level-of-service for movement

s/veh

Critical Movement d_A, Approach Delay Approach LOS d_I, Intersection Delay

Average control delay by approach approach

s/veh

Level-of-service for approach Average control delay for intersection

Intersection LOS

Level-of-service for intersection

Intersection V/C

Volume-to-capacity ratio for the intersection

s/veh

Sequence Editor Ring 1

User defines the Signal Groups that occur on Ring 1

Ring 2

User defines the Signal Groups that occur on Ring 2, if applicable

Ring 3


Ring 4


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8.3.1.2

Sequence Editor and Timing Diagram

In addition to the tabular data required for analysis, the HCM 2010 and HCM 2000 methods also take into account specific signal timing setups. This is done through the data inputs for Phasing & Timing along with the definition of the Signal Group / phase sequence. Upon defining the signal groups in the Phasing & Timing subtable, the user can define the sequence using one of the following methods. For simple intersection setups with standard phasing using only two rings and two barriers (standard 2-, 4-, 6-, or 8-phase intersections), define the lane configuration, priority scheme (major, minor), and control type for the intersection. Then, simply click on the Create Default Signalization icon . This will set the signal group numbers and create the sequence automatically. This sequence can be updated or changed manually. Clicking on the Signalization icon again will reset the signal group numbers and sequence to the default signalization. To define the sequence manually and for more complex intersection setups, the Sequence Editor allows sequence definitions across up to 4 rings and up to 8 barriers:

To define phase sequence, go to the desired cell and use the drop-down menu to select from the available signal groups. To insert a barrier, click anywhere on the divider between the two columns where the barrier should be inserted. To remove a barrier, click on the barrier again to toggle it off. Once the sequence is defined, the timing diagram will appear directly below showing the signal group numbers and associated splits for all vehicular and pedestrian signal groups defined in the Sequence Editor.

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8.3.1.3

Circular 212 for Signalized Intersections

The Traffic Control table for the Circular 212 methods for signals is shown in Figure 12: Traffic Control: Circular 212 for Signalized Intersections Table. Table definitions are presented Table presented Table 8: Traffic Control Parameters: Circular 212 for Signalized Intersections. Figure 12: Traffic Control: Circular 212 for Signalized Intersections Table

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Table 8: Traffic Control Parameters: Circular 212 for Signalized Intersections Parameter

Description


Analyze Intersection?

A check box indicates this intersection intersection will be included included in the analysis and reports. Phasing & Timing

Control Type Allow Lead/Lag Optimization Signal Group


Lead/Lag


The signal group is the signal phase number. All signal groups serving the movement. When the Control Type is “Overlap” and the Signal Group for the Overlap phase is entered, the Auxiliary Signal Groups cell is active and allows selections of all phases this movement overlaps with. Selection for Lead or Lag left turn for protected phasing. Saturation Flow

Lane Group


so, Base Saturation Flow per Lane

Base saturation flow rate

N, Number of Lanes


Veh/h/ln

Movement, Approach, & Intersection Results Critical Movement

Critical Movements for the intersection

Intersection LOS

Level-of-service for the intersection

Intersection V/C

Volume-to-capacity ratio for the intersection Sequence Editor

Ring 1

User defines the Signal Groups that occur on Ring 1

Ring 2


Ring 3


Ring 4


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8.3.1.4

ICU for Signalized Intersections

The Traffic Control table for the Circular 212 methods for signals is shown in Figure 12: Traffic Control: Circular 212 for Signalized Intersections Table. Table definitions are presented Table 8: Traffic Control Parameters: Circular 212 for Signalized Intersections. Figure 13: Traffic Control: ICU for Signalized Intersections Table

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Table 9: Traffic Control Parameters: ICU for Signalized Intersections Parameter

Description


Analyze Intersection?

A check box indicates this intersection will be included in the analysis and reports.

Cycle Length

Controller cycle length. This is the maximum time it will take for each signal group to cycle once. The cycle l ength is only used for coordination.

s

Loss Time

Total time per cycle not effectively being used due to driver reaction time, acceleration, and deceleration at the start and end of active s ignal groups. This is typically three to four seconds per signal group, times the number of signal groups.

s

Phasing & Timing Control Type Allow Lead/Lag Optimization Signal Group


Lead/Lag


The signal group is the signal phase number. All signal groups serving the movement. When the Control Type is “Overlap” and the Signal Group for the Overlap phase is entered, the Auxiliary Signal Groups cell is active and allows selections of all phases this movement overlaps with. Selection for Lead or Lag left turn for protected phasing. Saturation Flow

Lane Group


so, Base Saturation Flow per Lane

Base saturation flow rate

N, Number of Lanes


Veh/h/ln

Movement, Approach, & Intersection Results Critical Movement

Critical movements for the intersection

Intersection LOS

Level-of-service for the intersection

Intersection V/C

Volume-to-capacity ratio for the intersection

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8.3.2

Roundabouts

The traffic control workflow tables are presented for each of the roundabout intersection analysis methods, including HCM 2010 and Kimber.

8.3.2.1

HCM 2010 for Roundabout Intersections

The Traffic Control table for the HCM 2010 method for roundabouts is shown in Figure 14: HCM 2010 Traffic Control Table: HCM 2010 for Roundabout Intersections Table definitions are presented in Table 10: Traffic Control Parameters: Roundabouts - HCM 2010 for Roundabout Intersections. Figure 14: HCM 2010 Traffic Control Table: HCM 2010 for Roundabout Intersections

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Table 10: Traffic Control Parameters: Roundabouts - HCM 2010 for Roundabout Intersections Parameter

Description


Analyze Intersection? Analysis Period Number of Conflicting Circulating Lanes

A check box indicates this intersection will be included in the analysis and reports. Time period for the analysis, either 15 min or 1 hr. Number of lanes directly in conflict with the approach entry lanes.

Circulating Flow Rate

Number of vehicles circulating in the roundabout and passing in front of the entry approach, conflicting with the entry flow.

veh/h

Exiting Flow Rate

Number of vehicles exiting on the specific approach.

veh/h

Demand Flow Rate

Volumes represented as an hourly flow rate

veh/h

Adjusted Demand Flow Rate

Demand Flow Rate adjusted for heavy vehicles veh/h Lanes

Overwrite Calculated Critical Headway?

Checkbox to allow for overwriting of calculated critical headway value.

User-Defined Critical Headway

Value of critical headway, if defined by user

Overwrite Calculated Critical Follow-Up Time?

Checkbox to allow for overwriting of calculated critical follow-up time value.

User-Defined Critical Follow-Up Time

Value of critical follow-up time, if defined by user

A (intercept) B (coefficient)

s

s Capacity model intercept based on follow-up headway used for calibration Capacity model coefficient based on critical and follow-up headway used for calibration

HV Adjustment Factor

Adjustment factor for heavy vehicles, based on heavy vehicle percentage input in volumes table.

veh/h

Entry flow rate

Approach entry flow rate by lane

veh/h

Capacity of Entry and Bypass Lanes

Total capacity of entry and bypass lanes by approach

Pedestrian impedance

Capacity reduction factor to account for impedance of conflicting pedestrians

Capacity per Entry Lane

Entry capacity converted to vehicles per hour

X, volume / capacity

Volume to capacity ratio per lane of entry

veh/h

veh/h

Movement, Approach, & Intersection Results Average Lane Delay Lane LOS

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Average control delay per lane of entry

s/veh

Level-of-s2ervice per lane of entry

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Approach Delay

Average control delay for the selected approach

Approach LOS

Level-of-service for the selected approach

Intersection Delay

Intersection average control delay

Intersection LOS

Intersection Level-of-service

8.3.2.2

veh

ft s/veh

s/veh

Kimber for Roundabout Intersections

The Traffic Control table for the Kimber method for roundabouts is shown in Figure 15: Kimber Traffic Control Table: Kimber for Roundabout Intersections. Table definitions are presented in Table 11: Traffic Control Parameters: Roundabouts - Kimber for Roundabout Intersections. Figure 15: Kimber Traffic Control Table: Kimber for Roundabout Intersections

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Table 11: Traffic Control Parameters: Roundabouts - Kimber for Roundabout Intersections Parameter

Description

Units

Capacity Analysis Kimber Hollis c-Factor

In the queue length formula by Kimber-Hollis, the c-factor describes the variability of the inflow. Movement, Approach, & Intersection Results

Approach Entering Volume

Entering volume on approach determined from volume inputs.

veh/h

Approach Conflicting Volume

Circulating volume conflicting to specified approach.

veh/h

Approach Capacity

Approach capacity in passenger car units per hour

veh/h

Approach Queue Length

Expected queue length at the end of the observation period

veh

Approach Delay

Mean permitted delay in the observation period

s/veh

Approach LOS

Entry level-of-service based on Kimber mean delay and HCM 2010 unsignalized LOS table.

Intersection Delay

Intersection average delay

Intersection LOS


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8.3.3

Two-way Stop Controlled Intersections

The traffic control workflow tables are presented for each of the two-way stop controlled intersection analysis methods, including HCM 2010 and HCM 2000.

8.3.3.1

HCM 2010 for TWSC Intersections

The Traffic Control table for the HCM 2010 method for two-way stops is shown in Figure 16: Traffic Control Table. Table definitions are presented in Table 12: Traffic Control Parameters: HCM 2010. Figure 16: Traffic Control Table: HCM 2010 and HCM 2000 for TWSC Intersections

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Table 12: Traffic Control Parameters: HCM 2010 and HCM 2000 for TWSC Intersections Parameter

Description


Priority Scheme

Defined approach as either free or stop controlled

Flared Lane

A check box to indicate a flared lane on the stop-controlled approach

Storage Area

Number of vehicles that can be stored in the flared section

Two-Stage Gap Acceptance Number of Storage Spaces in Median Analyze Intersection? Analysis Period Population < 10000 (Signal Warrants)

veh

A check box to indicate two-stage gap acceptance is applicable

Number of vehicles that can be stored in the median veh

A check box indicates this intersection will be included in the analysis and reports. Time period for the analysis, either 15 min or 1 hr. Flag to indicate intersection is in an area with a population of less than 10,000 people; used for signal warrant analysis

Capacity Analysis Calculated Rank

Movement ranking in the priority hierarchy

v_c, Conflicting Flow Rate

Total conflicting volume (flow rate) for selected turning movement

veh/h

v_c, Stage 1

Total conflicting volume (flow rate) for selected turning movement for stage 1 of 2 during two-stage gap acceptance

veh/h

v_c, Stage 2

Total conflicting volume (flow rate) for selected turning movement for stage 2 of 2 during two-stage gap acceptance

veh/h

t_ c,Base, Base Critical Headway

Base critical headway based on geometry and movement. Critical headway is the minimum headway in a traffic stream for one vehicle to enter from a minor approach.

s

t_ c,Base, Base, Stage 1

Base critical headway based on geometry and movement for stage 1 of 2 during two-stage gap acceptance.

s

t_ c,Base, Base, Stage 2

Base critical headway based on geometry and movement for stage 2 of 2 during two-stage gap acceptance.

s

Base critical headway adjustment factor for heavy vehicles. (1.0 for major streets with one lane in each direction; 2.0 for major streets with two or three lanes in each direction)

s

t_ c,HV, Adjustment Factor for HV P_ HV, Proportion of HV

Proportion of heavy vehicles by movement

t_ c, G, Adjustment Factor for Grade

Base critical headway adjustment factor for grade

G, Percent Grade

Percent grade of approach

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%

s

%

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ppb,x, Pedestrian Impedance Factor t_ 3,LT, Geometry Adjustment

Pedestrian blockage factor or proportion of time that one lane on an approach is blocked during 1 h. (1) Adjustment factor for intersection geometry (0.7 for minor-street left turn movement at three-leg intersections; 0.0 otherwise)

s

t_ c,x, Calculated Critical Headway

Calculated critical headway for s elected movement after adjustments have been made.

s

t_ c,x, Stage 1

Calculated critical headway for selected movement for stage 1 of 2 during twostage gap acceptance after adjustments have been made.

s

t_ c,x, Stage 2

Calculated critical headway for selected movement for stage 2 of 2 during twostage gap acceptance after adjustments have been made.

s

Overwrite Calculated Critical Headway? t_ c,x,u, UserDefined Critical Headway

A checkbox overrides the calculated critical headway with the user-defined headway

User-defined critical headway s

t_ c,x,u, Stage 1

User-defined critical headway for stage 1 of 2 during two-stage gap acceptance.

s

t_ c,x,u, Stage 2

User-defined critical headway for stage 1 of 2 during two-stage gap acceptance.

s

t_ f,Base, Base Follow-Up Time

Base follow-up headway. Follow-up headway is the time between the departure of one vehicle from the minor street and the departure of the next vehicle using the same major-street headway, under a condition of continuous queuing on the minor street. (1)

s

t_ f,HV, Adjustment Factor for HV

Base follow-up headway adjustment factor for heavy vehicles. (0.9 for major streets with one lane in each direction, 1.0 for major streets with two or three lanes in

s

each direction) t_ f,x, Calculated Follow-Up Time

Calculated follow-up headway for s elected movement after adjustments have been made.

s

Overwrite A checkbox overrides the calculated follow-up headway with the user-defined Calculated headway Follow-Up Time? t_ f,x, UserDefined FollowUp Time

User-defined follow-up headway

c_ p,x, Potential Capacity

Potential capacity of the selected movement

s

veh/h

c_ p,x, Stage 1

Potential capacity of the selected movement for stage 1 of 2 during two-stage gap acceptance

veh/h

c_ p,x, Stage 2

Potential capacity of the selected movement for stage 2 of 2 during two-stage gap acceptance

veh/h

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p_ 0,j, Prob. Of Qfree State

Probability of a queue free state for the conflicting movement

f_ j,U, Rank 2 Maj. U-Turn Capacity Adjustment Factor

Capacity adjustment factor for presence of U-turns

f_ k, Rank 3 Capacity Adjustment Factor

Capacity adjustment factor that accounts for the impeding effects of

p', Adjustment to Impedance Factor f_ p,l, Rank 4 Capacity Adjustment Factor c_ m,x, Movement Capacity

Higher-ranked movements.

Adjustment to the major-street left, minor-street through impedance Factor Capacity adjustment factor that accounts for the impeding effects of higherranked movements.

Total capacity of selected movement

veh/h

c_ m,x, Stage 1

Total capacity of selected movement for stage 1 of 2 d uring two-stage gap acceptance

veh/h

c_ m,x, Stage 2

Total capacity of selected movement for stage 2 of 2 during two-stage gap acceptance

veh/h

c_T, Total Capacity

Total capacity of exclusive lane movement

c_SH, Capacity of Shared Lane Capacity

Total capacity of shared lane movement

c_R, Capacity of Flared Lane

Total capacity of flared lane movement

veh/h

veh/h

veh/h

Movement, Approach, & Intersection Results V/C, Movement V/C Ratio

Volume-to-capacity ratio for the selected movement

d_M, Delay for Movement

Control delay for the selected movement

d_ Rank1, Delay to Rank 1 Vehicle

Control delay to the rank 1 vehicle

Movement LOS

Level-of-service for the selected movement

Critical Movement

Movement with the highest control delay





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s/veh

s/veh

veh

ft

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d_ A, Approach Control Delay Approach LOS

Control delay for the selected approach

s/veh

Level-of-service for the selected approach

V/C_ I, Worst Movement V/C Ratio

Volume-to-capacity ratio for the movement with the worst (highest) delay value

d_ I, Worst Movement Control Delay

Delay value of the movement with the worst (highest) delay

d_I, Intersection Delay Intersection LOS

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s/veh

Average delay for the intersection

s/veh

LOS for the intersection (based on Worst Movement Control Delay)

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8.3.4

All-way Stop Controlled Intersections

The traffic control workflow tables are presented for each of the all-way stop controlled intersection analysis methods, including HCM 2010 and HCM 2000.

8.3.4.1

HCM 2010 and HCM 2000 for AWSC Intersections

The Traffic Control table for the HCM 2010 and HCM 2000 methods for all-way stops is shown in Figure 17: Traffic Control Table. Table definitions are presented in Table 13: Traffic Control Parameters: HCM 2010 & 2000. Figure 17: Traffic Control Table: HCM 2010 and HCM 2000 for AWSC Intersections

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Table 13: Traffic Control Parameters: HCM 2010 & 2000 for AWSC Intersections Parameter

Description


Analyze Intersection? Analysis Period Population < 10000 (Signal Warrants)

A check box indicated this intersection will be included in the analysis and reports. Time period for the analysis, either 15 min or 1 hr. Flag to indicate intersection is in an area with a population of less than 10,000 people; used for signal warrant analysis

Lanes Flow Rate

Flow rate for movement

Capacity per Entry Lane

Capacity

Geometry Group

Geometry group number based on intersection geometry

Proportion of LT Vehicles, PLT

Proportion of left-turning vehicles in the lane

Proportion of RT Vehicles, PRT

Proportion of right-turning vehicles in the lane

veh/h

Headway Adjustment Factor for LT, hLT-adj

Adjustment factor to reflect left-turn geometry

Headway Adjustment Factor for RT, hRT-adj

Adjustment factor to reflect right-turn geometry

Degree of Utilization, x

%

%

s

s

Headway Aggregated adjustment factor Adjustment, hadj Initial Departure Headway

veh/h

Average time between departures of successive vehicles on selected approach.

s

s

st

Default = 3.2s for 1 iteration Degree of utilization based on initial departure headway and lane flow rates

Departure Headway, hd

Average time between departures of successive vehicles on selected approach

s

Move-up time, m

Average time for vehicle to move up to stop bar after preceding vehicle departs.

s

Service Time, ts

Average time spent by a vehicle in first position waiting to depart

s

Movement, Approach, & Intersection Results Average Lane Delay

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Control delay for the selected movement

s/veh

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Approach Delay

Control delay for the selected approach

Approach LOS

Level-of-service for the approach

Intersection Delay

Intersection Control delay

Intersection LOS


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veh

ft s/veh

s/veh

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Traffic Impact Analysis (TIA)

9


Vistro provides all the functionality to complete a traffic impact analysis. The Workflow Panel provides the steps required to complete your TIA analysis: 1. Trip Generation: Input all the trip generation data for each zone 2. Trip Distribution: Use the tables to distribute trips between Zones and Gates 3. Trip Assignment: Assign development trips to the network along the previously built Paths Completing these steps allows you to track your development trips through the network and account for them at each intersection. To complete each of these steps, activate the appropriate data table in the Workflow Panel.

9.1

Trip Generation

In this Workflow step, you will enter the Trip Generation data for each development Zone in the network in a tabular setup. The data entry is all user-defined with calculations completed based on your entries. Data entry is similar to other data tables in the Workflow Panel, using text and numerical entries, drop-down lists, and checkboxes, as shown in Figure 18: Trip Generation Table. Each of the trip generation entries are described in Table 14: Trip Generation Parameters. Figure 18: Trip Generation Table

Table 14: Trip Generation Parameters Parameter

Description

Details

No

Zone number

Name

Zone name

Project name

Land Use

Description of land use type

Examples include single family residential, office, retail, etc.

Land Use Code

Code number for referencing land use type

Example would be use of ITE land use code from Trip Generation Manual

Data Entry

Rate or Trips

Users can enter either a trip generation rate or directly enter the number of trips

Independent Variable

Variable that is the basis of the trip generation rate

Examples include dwelling units, thousand square-feet of leasable area, occupied hotel rooms, students, etc.

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Trip Generation Rate

Trip generation rate per independent variable, for the time period of analysis

Quantity

Quantity of the Independent Variable

% In

Percentage of trips that are inbound to the Zone

% Out

Percentage of trips that are outbound from the Zone

Trips Generated

Number of trips generated

Product of Independent Variable x Trip Generation Rate x Quantity

Trips In

Number of trips generated inbound to the Zone

Product of Trips Generated x % In if Data Entry = Rate, or user entered value if Data Entry = Trips

Trips Out

Number of trips generated outbound from the Zone

Product of Trips Generated x % Out if Data Entry = Rate, or user entered value if Data Entry = Trips

Trip Type

Trip added to or removed from the network

Analyze

Checkbox to select if Zone should be analyzed or not in curre nt scenario

Comment

Added should be selected for all new trips to the network (i.e., from new development projects); Removed should be selected for trips to b e removed from the network (i.e., to represent existing trips from a land use that will be removed). When checked, trips from the Zone will be generated for the current scenario.

Comment field for user text entry

The trip generation data are applied, along with the trip distribution data entered in the Trip Distribution Workflow Task Table (Chapter 9.2 Trip Distribution on page 95) and the Path percentages entered in Trip Assignment Workflow Task Table (Chapter 9.3 Trip Assignment on page 98), to determine the traffic assignments on the network.

9.2

Trip Distribution

Trip distribution inputs are entered in the Trip Distribution Workflow Task Table. The percentages of trips from each Gate and/or Zone in the network to the Zone of interest are entered to reflect the trip distribution of inbound trips (Figure 19: Trip Distribution Table) . Similarly, the percentages of trips from the Zone of interest to each Gate and/or Zone in the network are entered to reflect the trip distribution of outbound trips.

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Figure 19: Trip Distribution Table

The table for each zone can be collapsed or expanded, to allow for ease of viewing, by clicking the triangle shape on the left-side of the table header bar for each zone. The search entry box can be utilized to search for a specific zone in the network. The trip distribution percentages are utilized, along with the trip generation data entered in the Trip Generation Workflow Task Table (see Chapter 9.1 Trip Generation on page 94) and the Path percentages entered in Trip Assignment Workflow Task Table (Chapter 9.3 Trip Assignment on page 98), to determine the traffic assignments on the network. Trip Distribution parameters are described in the table below.

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Table 15: Trip Distribution Parameters Parameter

Description

Zone #: Name

Reference Zone # and Name for subtable

To Zone Name

Trips entering the Zone from other Zones and Gates

From

Zone or Gate trips come from (to enter subject Zone)

From Share, %

Percent Share of trips for subject Zone that are distributed to each Zone or Gate

From Trips

Total number of trips for the subject Zone that are distributed to each Zone or Gate, based on the From Share %

From Zone Name

Trips exiting the Zone to go to other Zones and Gates

To

Zone or Gate trips travel to

To Share, %

Percent Share of trips from each Zone and Gate distributed to the subject Zone

To Trips

Total number of trips for each Zone and Gate distributed to the subject Zone, based on the From Share %

It should be noted that, due to data consistency, changing a share % for one Zone may change the share % for another Zone as the number of trips from one zone to another zone may not be represented as the same Share % for each of those zones. Vistro also provides additional functions to assist with data entry. These are described below: Table 16: Trip Distribution Functions Function

Description

Zone and Gate Name

Enter a Zone / Gate name in the table. The Zone number and name will be shown.

Search Zone

Window with drop-down list of all Zones in the network. Selecting a Zone in this search window will collapse all other tables in view. To search, select the down arrow to s ee the entire list. You can also type in the Zone number or name directly. Note that this search is c ase sensitive.

Mirror Distribution

If you have the same distribution for trips entering the Zone as leaving the Zone, you can input the share % for either the To or From and mirror that distribution for the other direction by using the left and right arrows in the header of each subtable.

Column Filter

Use the filter for the Share % or Trips to view only specific values (e.g., only show values greater than 0%).

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9.3

Trip Assignment

After the Trip Generation and Trip Distribution have been defined, you can assign your development trips to the network in the Trip Assignment step. Here, you define the allocation of the shares of trips to take specific paths between each zone and gate / zone and zone pair. Figure 20: Trip Assignment Table shows the interface. Figure 20: Trip Assignment Table

The table above will show any Paths already created in your network, including those created using the Path tool, as described above (see Chapter 9.1 Trip Generation on page 94). You will complete the Trip Assignment in two steps: 1. Add all Paths for your Trip Assignment 2. Define the Volume Share for each Path

Add Paths for your Trip Assignment You can add Paths as described above, using the Path tool. In addition, in the Trip Assignment step, you can also use the Add Missing Paths function, which will look for any Zone-Zone and Zone-Gate pair that does not currently have at least one Path defined and generate the shortest distance path for that pair.

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This is useful if you want to generate an initial set of Paths without using the Path tool. It is also useful if you add Zones and/or Gates and need to provide at least one Path between the new Zones & Gates. When a row is selected in the Trip Assignment Workflow Table, the corresponding path is displayed visually in the network window (Figure 21: Path Graphical Representation of Trip Assignment Row Selected) Selected).. Figure 21: Path Graphical Representation of Trip Assignment Row Selected

The volume share (path percentages) entered here are applied, along with the trip generation data entered in the Trip Generation Workflow Task Table (Chapter 9.1 Trip Generation on page 94) page 94) and and the trip distribution data entered in the Trip Distribution Workflow Task Table (Chapter 9.2 9.2 Trip Distribution Distribution on page 95) page 95),, to determine the traffic assignments on the network. The Trip Assignment Parameters are described in the table below.

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Table 17: Trip Assignment Parameters Parameter

Description

Name

Path Name – Name – enter enter it directly in the cell. For those paths that are generated through the Add Missing Paths function, the default name is “Automatically generated” but this can be edited.

Origin

Start of the Trip Assignment Path Zone / Gate Number

Origin Name

Start of the Trip Assignment Path Zone / Gate Name

Destination

End of the Trip Assignment Path Zone / Gate Number

Destination Name

End of the the Trip Trip Assignment Path Zone / Gate Name

Volume Share, %

Percent of volume for that that Zone-Zone Zone-Zone or Zone-Gate pair assigned assigned to the specific Path

Volume

Volume for that Zone-Zone or Zone-Gate pair assigned to the specific Path

Length, ft or m

Length of the Path measured from the network entry point to the network exit point (it does not include the distance from the network end points to the Zone / Gate)

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Signal Optimization

10 Signal Optimization Vistro provides you two levels of optimization: 

Local Optimization




Local and Network Optimization can be applied to any signalized intersection in your network that is designated as Coordination Type = Coordinated. The optimization can then be applied to any Actuation Type (Fixed, Semi-Actuated, Fully Actuated). The following sections describe the steps and methodologies for each level of optimization.

10.1 Local Optimization Optimization Intersections can be optimized at the local level, meaning that no coordination is taken into account. At the local level, you can optimize for the following: 1. Splits or 2. Splits and Cycle Time To utilize the local optimization, intersections to be optimized must have the following: 

Signal timing data inputs, including signal group designations and sequence)



"Coordination Type = Coordinated"

Then, you can optimize each intersection individually or all intersections in your network at one time (with no interaction between intersections). The steps for local optimization are below with a description of the methodology following. Note that when a single signal controller is assigned to multiple intersections, the local optimization will be based on the data inputs for all intersections of that controller. All intersections of the signal controller will be optimized and adjusted simultaneously.

10.1.1 Local Optimization for a Single Intersection To optimize for Splits only: 1. While in the Traffic Control table, Click on the Optimization Splits dialog:

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button to access the Local

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Signal Optimization

2. Select the desired Objective Function. 3. Click OK. OK. To optimize for Splits and Cycle Time: 1. Click on the

button to access the Local Optimization Splits and Cycle Time dialog:

2. Select the desired Objective Function. 3. Set the boundaries for the Cycle Time optimization. optimization . 4. Click OK. OK.

10.1.2 Local Optimization for All Intersections To optimize all intersections in the network using the Local Optimization: 1. Go to the Signal Control > Local Optimization in Optimization in the Menu Bar to access the Local Optimization Splits dialog for all intersections:

2. Select the desired Objective Function. 3. Define the Cycle Optimization Optimizati on Settings. 4. Click Save Settings to Settings to save the settings without optimizing or Optimize All Intersections to Intersections to complete the local optimization for all intersections. You can then view the results in the time-space diagram under the Optimization Workflow. Page 102/211

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10.1.3 Local Optimization Methodology The two Local Optimization options are described here.

10.1.3.1 Local Split Optimization Basics Splits are optimized locally through one of two methods: 1. V / C Balancing 2. Minimize Critical Movement Delay The Local Split Optimization is done by applying a revised simplex algorithm. The following steps are necessary for calculating the green time split: 1. Calculate adjusted volume and saturation flow rate for each lane group (already calculated for capacity analysis). 2. For each SG in the signal timing plan, determine the critical lane group. 3. Allocate splits based on critical lane group V/C ratios. 4. If Minimizing Critical Movement Delay: Shift green time from non-critical to critical movement until no movement m c can be improved without making another movement mn worse than m c. 5. Check that the allocated green times meet all the constraints (user defined Minimum Green, Amber and Red Times, as well as Pedestrian Walk and Clearance Times).

10.1.4 Split and Cycle Time Optimization Basics With this option, the splits are optimized locally as described in 10.1.5 Local Split Optimization Objective Functions while the Cycle Time is optimized with respect to overall intersection delay. The following steps are necessary for calculating the optimum cycle time: 1. Determine the set T of permitted cycle times at the Signal Controller is defined by the user in the Local Optimization Dialog. 2. To each permissible cycle time t from T the following applies: a.

Specify optimal splits s*(t) for predefined cycle time t.

b. Use ICA to calculate the total delay at the node for s*(t). 3. As an optimal cycle time t* select the t with minimum total delay. In addition, set the optimal split s*(t*). The ICA calculation of the total intersection delay at the intersection only provides valid

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values, if the sum of critical V/C ratios is smaller than or equal to 1. To greater sums always t* = max(T) applies.

10.1.5 Local Split Optimization Objective Functions As stated above, there are two options for the Objective Function for Local Split Optimization: 

V / C Balancing



Minimize Critical Movement Delay

The process can be described graphically as well as in Figure 22. Local Split Optimization. Figure 22. Local Split Optimization

10.1.5.1 V / C Balancing for Local Split Optimization V / C Balancing is a common optimization objective that aims to minimize overall intersection delay by equalizing the volume-to-capacity ratio for the critical signal groups at the intersection. The result can be inspected by analyzing attribute X in the Lane Group Results sub table in the Traffic Control tab. In the example shown in Figure 23. V / C Balancing Example, the first ring in the first barrier (SG 1 and 2) and the second ring in the second barrier (SG 8) are critical, because they are the highest in their respective barriers. After split optimization, V/C for SG 1, 2 and 8 are equal, while V/C for SG 6 and 4 are lower (not critical).

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Figure 23. V / C Balancing Example

10.1.5.2 Minimize Critical Movement Delay for Local Split Optimization With the Minimize Critical Movement Delay option, the objective is to minimize the delay for the critical movements at the intersection. The result can be seen by analyzing the attribute d_M in the Movement, Approach & Intersection sub table of the Traffic Control tab. The result is a more equal average movement delay. In comparison to the V/C balancing method, the critical movement delay is lower (Figure 24. Example Results Using “Minimize

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Critical Movement Delay”) but the overall intersection delay is higher than using the V/C Balancing method (Figure 25. Example Results Using “V/C Balancing” ). Both objectives are valid and it is a decision by the modeler which one to use. Figure 24. Example Results Using “Minimize Critical Movement Delay”

Figure 25. Example Results Using “V/C Balancing”

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10.1.6 Cycle Optimization Settings Cycle time optimization is always based on overall intersection delay. To define the allowed cycle times, the user has two options: 

Between Boundaries



Try Set

These options are selected as described above with the parameters defined below.

10.1.6.1 Cycle Time Optimization Between Boundaries Figure 26. Cycle Optimization Settings Between Boundaries

With this option chosen, as shown in Figure 26. Cycle Optimization Settings Between Boundaries, you can define a lower and upper bound for the Cycle Times to be evaluated during the optimization. You also set the Step Size that is applied when searching for the optimum Cycle Time. Example: Lower Bound = 60 Upper Bound = 120 Step Size = 10 In this example, the optimizer checks cycle times 60s, 70s, 80s, 90s, 100s, 110s, and 120s and selects the one that gives the lowest intersection delay.

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10.1.6.2 Cycle Time Optimization Try Set Figure 27. Cycle Optimization Settings Try Set

With this option, you define a specific set of Cycle Times that will be tested for optimality. The Cycle Time from this set that gives the lowest overall intersection delay will be selected.

10.2 Network Optimization Optimization Vistro also provides robust Network Optimization. In contrast to the local optimization (although it can also be carried out for all intersections), Network Optimization considers the interaction between signalized intersections. These interactions cannot be analyzed with HCM methods, but are modeled by the means of a platoon dispersion model that models platoons travelling through the network (see 10.2.3.3 Platoon Dispersion Model on page 117 page 117 for a more detailed description). The platoon dispersion model provides vehicle delay and number of stops, considering the signal plans at included intersections as well as their relative position in time and space (distances between intersections and signal offsets). The objective of the optimization is to adapt the signal timing in such a way that vehicles can pass several consecutive signal controls on green. In Vistro, Network Optimization will optimize all signals that belong to one Signal Coordination Group, regardless of whether they are aligned linearly or in a network context. Good coordination requires the Signal Controllers to either have the same cycle times or that the cycle times are in a ratio 2:1. If this is not true for all Signal Controllers in one Signal Coordination Group, Network Optimization will only be carried out for this Signal Coordination Group, if cycle time optimization is activated. In this case, you will receive detailed information in the " error.txt " file that can be opened from the Progress Monitor (see section 10.2.5 section 10.2.5 Network Optimization Progress Monitor on page 121) page 121).. Furthermore, coordination is most effective when the signals are located close to each other. As the distance distance between between signals signals increases, increases, the platoon platoon dissipates. dissipates. If If the signals signals are spaced spaced too far from each other, the platoon will dissolve entirely from one signal to another. This results in arrivals that are virtually uniformly distributed and thus, the wait time cannot be influenced through the choice of the offset and other timing parameters. Therefore, optimizing all signal controllers in the network at one time may not be effective. Instead, it Page 108/211

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may be more beneficial to use the distant intersections as “natural” boundaries for the Signal Coordination Group definitions, which allow those intersections to be optimized together.

10.2.1 Network Optimization Setup To utilize the Network Optimization, intersections to be optimized must have the following: 

Signal timing data inputs, including signal group designations and sequence)



"Coordination Type = Coordinated"

In addition, you must also: 

Define Coordination Groups; and



Define Routes and assign Weights to them.

These are described in the subsection below. Once this is set up, you can then set up and run the Network Optimization by following these steps: 1. Go to the Signal Control > Network Optimization in Optimization in the Menu Bar to access the Network Optimization Dialog:

2. Select Parameters to be optimized. 3. Select Coordination Sub Groups to be optimized.

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4. Select and parameterize Optimization Method. 5. Click on Run Optimization. You can then view the results in the time-space diagram under the Optimization Workflow.

10.2.1.1 Network Optimization Signal Coordination Groups Signal Coordination Groups define groups of Signal Controllers to be optimized collectively. Signal Controllers (in most cases there is a 1:1 relation between Signal Controller and intersection) that belong to the same Signal Coordination Group are coordinated. That means that in the traffic model that is used for the calculation of the objective function (delay and number of stops), platoons are considered that travel between any two intersections that belong to the same Signal Coordination Group. Signal Coordination Groups are optimized one by one, i.e. signalized intersections that belong to other or no Signal Coordination Group are not optimized in that run. Therefore it is in most cases important that neighboring signalized intersections belong to the same Signal Coordination Group. To define Signal Coordination Groups, do the following: 1. Go to Menu Signal Control > Coordination Groups to Groups to bring up the Coordination Groups dialog:

2. Click on the 3.

button to add a new Coordination Group.

Click in the Name cell to enter or edit a Coordination Group Name.

4. To delete a Coordination Group, highlight the Number and click on the

.

5. Click on OK to OK to exit. 6. In the Traffic Control Workflow tab, define define the Signal Coordination Group for each intersection by selecting the desired Coordination Group from the drop-down menu By default, Signal Controllers are not assigned to any signal coordination group and are not optimized in the context of network optimization.

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10.2.1.2 Network Optimization Routes Vistro provides the ability to define Optimization Routes. These Routes allow you to: 



View time-space diagrams to see optimization results;

“Weight” Routes in relation to each other to prioritize specific Routes when optimizing the network.

They can be defined in the network editor. 1) Select the

Route button from the Toolbar.

2) Left-click on the first intersection to start the Route. 3) Continue clicking on adjacent intersections to define the Route. As you create the route, you will see the route highlighted in green on the network with arrows pointing in the direction of the Route travel, as shown in Figure 28. Optimization Route Definition in the Network. 4) To delete the last selected intersection, use the Backspace key on your keyboard. 5) Double click to complete the Route. 6) In the Network Optimization Workflow Tab, define a Name and Weight for the Route. Once a route is defined, select the Route in the table and right-click for the following options: 



Delete Route – completely delete the path from the network Create Reverse Route – create the route using the same nodes and links but in the opposite travel direction from the selected Route

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Figure 28. Optimization Route Definition in the Network

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10.2.2 Network Optimization Process The Network Optimization process in Vistro is shown in Figure 29. Network Optimization Process Overview below. Figure 29. Network Optimization Process Overview Network Optimization

Method

HC Parameter: Number of Starting Solutions Hill Climb

Genetic Algorithm Spatial Extent Set of coordination groups Cycle Time Optimization (y/n) Upper bound Lower bound Step Size

GA Parameters: 1. Objective Function Weighting factors a. For Delay b. For Number of Stops 2. Max. Number of Iterations 3. Population Size 4. No. of Iterations w/o Improvements 5. Minimum Improvement

Allow half cycles (y/n)

Offset Optimization Precision (1s, 0.5s, 0.2s or 0.1s) Lead/Lag Optimization (y/n)

S lit O timization

/n Method

The various stages of the process are described in the following subsections.

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10.2.3 Network Optimization Methods Vistro provides two Network Optimization algorithm options: 

Genetic



Hill Climbing

In addition, a platoon dispersion model is used, as indicated previously. These two algorithms are very different and will produce varying results. The Objective Function and Settings for each are described below followed by the details of the platoon dispersion model.

10.2.3.1 Genetic Algorithm Network Optimization Genetic Algorithm is the default optimization method for network optimization in Vistro. Genetic Algorithms (GA) are widely used in several areas where automatic optimization is needed. There exists a huge number of books describing GA in detail, such as Holland 19751 and Goldberg 1989 2. GA are inspired by the process of evolution, the principle workflow is shown in Figure 30. Genetic Algorithm Fundamental Workflow.

1

Holland, John H (1975), Adaptation in Natural and Artificial Systems, University of Michigan Press, Ann Arbor 2 Goldberg, David E (1989), Genetic Algorithms in Search, Optimization and Machine Learning, Kluwer Academic Publishers, Boston, MA. Page 114/211

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Figure 30. Genetic Algorithm Fundamental Workflow

Generate initial Population Evaluate Population

Stopping

yes

Get solution

no

Selection (incl. Elitism) Crossover Mutation New Population

There is a population of individuals (here: signal plans) and each of the individuals has a certain fitness (here: objective function, weighted sum of delay and number of stops, to be minimized). Every individual has a probability to be selected for reproduction for the next generation, where the probability is higher with a higher fitness (analogy to the evolution). Several so called genetic operations can be performed in the reproduction process. 

Crossover



Mutation

To never get worse with the next iteration, the best individual of every generation is taken over directly to the next generation. As shown in below, the Genetic algorithm allows you to adjust the Objective Function factors and define the optimization settings, providing you control over the level of robustness and speed of the optimization of your network.

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Figure 31. Genetic Network Optimization Settings

Objective Function The optimization algorithm aims to minimize the objective function. The objective function is the weighted sum of (a) total vehicle delay (hours) and (b) the number intersections where a vehicle has to stop over all vehicles. The user can define the weights for the two factors.

Maximum Number of Iterations Maximum Number of Iterations specifies how many iterations (or: generations) there can be if no other termination criterion is met. In general, the higher Maximum Number of Iterations is, the longer the optimization may take. However, this value should not be too low, as Maximum Number of Iterations should not be the termination criterion (because there is still improvement, otherwise the termination criterion Number of Generations without Improvement would be met. In other words: There is still potential for improvement).

Population Size Population Size specifies the number of individuals (network wide signal plans) there is per generation. Generally, the higher this number is, the better the chances to find the optimum. The computation time can be up to proportional to the population size (if Maximum Number of Iterations is the relevant termination criterion).

Number of Generations without Improvement Number of Generations without Improvement specifies after how many generations with no improvement (or: less than Minimum Improvement, see next section) the optimization terminates.

Minimum Improvement Minimum Improvement specifies how much better the solution has to be to be considered better. Example: if this is 1%, then an improvement of 0.5% will not be considered as an improvement.

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10.2.3.2 Hill Climbing Method Network Optimization The Hill Climbing Method is another option available in Vistro. The Hill Climb method uses the same Objective Function as the Genetic Algorithm. Due to its different approach, you only need to define the Number of Starting Solutions, as shown in Figure 32. Hill Climbing Network Optimization Settings. Figure 32. Hill Climbing Network Optimization Settings

Number of Starting Solutions The user can define how many starting solutions are used. The starting solutions are generated randomly. The current solution is always included in the set of starting solutions. The final solution is the best of all optimized solutions.

10.2.3.3 Platoon Dispersion Model Important for coordination is the behavior of the vehicle platoon during the journey from one Intersection to another (or: one Signal Group to another). Vistro determines platoons by analyzing the movement based total analysis volumes. It is calculated how many vehicles on their way first pass their Signal Group at the first Signal Controller and then their Signal Group at the second Signal Controller. We call such a combination of two consecutive Signal Groups with one volume a "coordination path leg". Optimization treats the traffic flows on all path legs interdependently. In each case it is assumed that within a cycle all vehicles start as a platoon at the beginning of the green time. This means, that beginning with the green time start, outgoing vehicles flow off with the saturation flow rate, until the volume per cycle has been exhausted. The platoon resolution or dispersion, solely caused by different vehicle speeds, describes the platoon development formula according to Robertson 1969 3. This model discretely divides the time in increments of 1 second and displays the number at time t‘ , at which a vehicle arrives at the end of a coordination path leg as a function of the number at time t < t‘ , at the beginning of the coordination path leg departing vehicle. Figure 33. A simple case of Platoon

3

Robertson, D.I. TRANSYT - A Traffic Network Study Tool. RRL Report LR 253, Road Research Laboratory, U.K., 1969.  PTV AG Feb-16

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Dispersion (Source: Figure 3-19 from Traffic Control Systems Handbook, Chapter 3 [FHWA]) shows a simple case of platoon dispersion between two intersections. Figure 33. A simple case of Platoon Dispersion (Source: Figure 3-19 from Traffic Control Systems Handbook, Chapter 3 [FHWA])

′+   ∙  1 ∙′+− :   1⁄1  

Number of vehicles arriving at the end of the coordination path leg is calculated as follows:

: Number of vehicles arriving at the end of the coordination path leg in time step t

: Number of vehicles departing at the beginning of the coordination path leg in time step t ,  = 0.35,  = 0.8

:

Travel Time on the coordination path leg (based on user defined approach speed and distance)

For calculating queue lengths it is presumed that separate lanes of sufficient length exist for separate Signal Groups at an approach. Vistro generally assumes "vertical" queues and does therefore not consider spillback upstream over several links or have an effect on the capacity of the turns of other Signal Groups.

10.2.4 Network Optimization Settings After selecting the desired method for optimization, you can then set various parameters to define the Network Optimization. These options are shown in Figure 34. Network Optimization Settings. Page 118/211

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Figure 34. Network Optimization Settings

Coordination Groups

Here the user can select from a drop down list which coordination groups he wants to be optimized. The drop down list contains all coordination groups that exist (per definition at the SC in the traffic control tab). Selection of multiple coordination groups is possible, the selected groups show up as a comma separated list in the closed drop down menu if this is easy to implement. If it is hard to implement, the selection can just be a persistent selection/marking of the selected groups that is visible if the user opens the drop down list. Optimization is carried out for each coordination group separately, i.e. cycle times can be different for different coordination groups.

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Split optimization

The user can select optimization of only Splits (no Cycle Time Optimization). The user can then define the percent of reduction from the optimum split that would be allowed during the optimization process. No further parameters defined here. The constraints (minGreen etc.) are taken as defined in the Traffic Control tab.

Cycle time optimization

If the user selects Split and Cycle Time Optimization, then they define a range of cycle times that are optimized. The user inputs the following: 

Lower boundary cycle time



Upper boundary cycle time



Step size (any integer)

The lower boundary is tested, every increment using the step size, and finally the upper boundary (even if the given step size would not find this upper boundary). Half cycles are always allowed. Vistro retains the relation of the cycle times in a coordination group throughout the cycle time optimization. If a controller has a half cycle before the optimization, it will have a half cycle after the optimization. The Lower Bound and the Upper Bound parameters refer to full cycles. If, for example, Lower Bound and Upper Bound are set to 60s and 240s, respectively, half cycles between 30s and 120s will be used.

Offset optimization

The user can specify the precision to be applied when searching for the optimum offsets. The user can choose between 1s, 05s, 02s and 0.1s. Generally, lower values are more precise but will make the optimization more complex and hence more time intensive.

Allow Lead/Lag Optimization

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If Lead/Lag optimization is allowed, then for every signal group combination that allows (as defined in the Traffic Control tab) for Lead/Lag optimization, Leading and Lagging green phases are tested.

10.2.5 Network Optimization Progress Monitor When running the Network Optimization, Vistro provides a Progress Monitor dialog, as shown in Figure 35. Network Optimization Progress Monitor. Figure 35. Network Optimization Progress Monitor

The progress monitor appears once the network optimization is initiated. It shows the progress of the optimization and allows you to manually interrupt the optimization (before one of the user-defined termination criteria makes the optimization process stop automatically). The progress is shown as a graph: The horizontal axis shows the number of iterations (time), the vertical axis shows the value of the objective function (currently best solution). The objective function value is monotonically decreasing. You may end the optimization e.g. because the current solution is acceptable or because it seems that the performance solution is not improving.

In this dialog, there is also access to an "error.txt" and a “messages.txt” file. The “error.txt” provides you information when the optimization could not been carried to help you identify problems that caused the optimization to not run properly. The “messages.txt” file provides detailed information about the optimization itself, including the parameters tested and the resulting Performance Index (PI) for each iteration of testing.

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10.2.6 Network Optimization Tab Vistro provides access to Network Optimization results graphically in the Network Optimization Tab. The Network Optimization tab is shown below. Figure 36. Network Optimization Tab

5

6 7 1

2

8

3

4 9

(1) Path Display The path is schematically displayed. In the default view the icons have the following meanings: 

Filled circle: Signalized node which is traversed by both paths



Empty circle: Node without signal control which is traversed by both paths





Filled triangle: Signalized node which is traversed by just one path (initial or reverse direction) Filled triangle: Node without signal control which is traversed by just one path (initial or reverse direction)

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You can change the colors of the margins and the fillings of the icons and you can change the link display.

(2) Intersection Labels 

Upper Part Number: Intersection ID



Upper Part Number: SC ID

(3) Cycle Time and Offset Cycle times and offsets of the respective Signal Controllers are displayed.

(4) Time Space Diagram With the Time Space Diagram you can display the signal times of signal controls along a route. The green bands start at the green times of the upstream (initial direction) signal group. In accordance with the defined speed and distance, they extend in driving direction to the next signal group. The diagram indicates whether a green band encounters a green phase at the next signal control. For the Time Space Diagram you need at least one user-defined route. The route must traverse at least two signalized intersections. Additionally, the cycle times of the signal controls must meet the following requirement: The longest cycle time must be smaller or equal the greatest common divisor of all cycle times multiplied by eight.

(5) Route List The route list shows all existing routes. Here, the user definable route attributes (Name and Weight) can be edited. Routes can be deleted by selecting a route in the list and hitting the delete key or using the context menu. No. Incremental value. Name User defined attribute to specify the route. Length Calculated length of the route (based on actual shape). Weights User defined attribute to specify relative weighting of each optimization route during the optimization process.

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(6) Signal Time-Space Diagram Mode Flowing Off On the basis of green times of the displayed turn on a signal control, the Flowing Off option visualizes the possible range in which vehicles can drive with the predefined speed to the next signal control.

Arterial Bands The arterial band visualizes only the range in which a vehicle which drives at the predefined speed reaches all signal controls on the path at green. Therefore it is a subset of the green bands visualized with the Flowing Off option. Show Reverse Direction If a route is defined in both directions (two separate route definitions, see Section 10.2.1.2 Network Optimization Routes for details on how to define this), then the time space diagram can show either a single direction or both directions by checking this option. If no route in the opposite direction exists, this option will not be available.

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(7) Max. Signal Time Here, the period of time to display on the time axis of the Time Space Diagram is defined.

(8) Network Optimization Dialog Here, you can access the network optimization dialog (like from the Optimization menu).

(9) Offset Adjustment The user can graphically drag the green splits left and right to manually adjust the offsets.

10.2.7 Unsignalized intersections Unsignalized intersections affect network optimization through the disruption of platoons. Vehicles break up platoons when they have to yield or stop to give right of way at roundabouts, all-way stop intersections, and on the stop-controlled movements of two-way stop control intersections. This causes the departure pattern at the intersection to be significantly different from the arrival pattern and, therefore, platoons cannot be assumed through these intersections making coordination between upstream and downstream intersections not possible. During the optimization of the network, downstream of these movements a random vehicle arrival is assumed (no platooning).

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Mitigation

11 Mitigation Vistro provides a Mitigation process, which allows you to evaluate potential mitigation measures for intersections that may not meet operational standards. Upon editing the inputs while testing mitigations, the calculations change “on the fly” to provide the user with an interactive mitigation testing environment. The Mitigation Table is shown below. Figure 37. Mitigation Tables

In the Mitigation table, the Unmitigated condition is always present. Here, you can see the basic Intersection Setup and Traffic Control parameters associated with the overall operations at the intersection. Any changes made in the Unmitigated condition will be applied to the network. Page 126/211

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Mitigation

For each Mitigation Option, the Unmitigated Summary is shown at the top of the table for easy comparison. In this Mitigation Option table, you can change the Control Type, Analysis Method, and the associated geometry and traffic control parameters. Not all parameters are available for editing in the Mitigation Option as the intent is to provide a reasonable analysis with minimal data entry to evaluate the feasibility of various Mitigation measures. Additional functions and features enable easier Mitigation testing as well as comparison of results across the Options, as summarized below. Table 18: Mitigation Functions and Features Function Add Mitigation Option

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Description Click to add a new Mitigation Option. Vistro allows up to 99 individual options per intersection

Delete Mitigation Options

Click to remove this Mitigation Option from the Mitigation Table.

Rename Mitigation Option

Double click on the Tab name to edit the name.

Duplicate

Generates a duplicate Mitigation Option

Print

Prints summary of current Mitigation Option

Print All

Prints summary of all Mitigation Options

Optimize Splits and Cycle Time

Optimizes local splits and cycle time for current Mitigation Option

Optimize Splits

Optimizes local splits only (maintains cycle time) for current Mitigation Option

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Reporting

12 Reporting Vistro provides a complete set of report-ready tables and figures, formatted for efficiency, easy-reading, and jurisdictional review. The following sections detail how to create your report and a description of the reports generated.

12.1 Report Layout Report production can be initiated in the Reporting dialog window available from File > Print Report… (Figure 38: Reporting Dialog Window) . Figure 38: Reporting Dialog Window

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There are 5 tabs: 

Page Layout: Define the page layout and prepare for printing



Select Reports: Select which tabular and graphical reports to include in the report



Report Nodes: Select which nodes to include in the report and define hourly volume factors for signal warrant analysis at all unsignalized intersections



Report Zones: Select which Zones to include in the report



Report Routes: Select which optimization Routes to include in the report

The reports in Vistro can be configured in a variety of ways in the Page Layout tab, as described in the table below. Table 19: Report Layout Options Parameter

Description

Save File as

Select path and filename to store the report

File Format

Choose the format for the report. Options are: 

CSV (tabular reports only)



HTML



PDF (pdf)

Page Layout

Choose the page layout (A4 or Letter)

Background

Choose the background for the figures. Options are:

Allow Map / Network Rotation



Network Model (without street names)



Network Model (with street names)



Map (without street names)



Map (with street names)



Map (without street names) & Network Model (without street names)



Map (with street names) & Network Model (without street names)



Map (without street names) & Network Model (with street names)

Select to rotate the map and/or network.

Rotate IDs like Map

Select to rotate intersection IDs.

Show Intersection Names

Print Intersection Names above the bubbles in the figures generated in the report.

Show Numbers of Report Figures

Print numbers on the figures generated in the report.

First Figure Number

Set the number for the first figure in the report.

Open Report After Print

Select to open the report in the chosen format after printing is complete.

Print

Print / create the report.

Cancel

Cancel out of the dialog and return to the network.

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In addition, you can add headers and footers by dragging and dropping the elements to the placeholders on the Report page, as shown in the figure below. Figure 39: Reporting Page Layout

Header and Footer data options are summarized in the table below. Table 20: Report Headers and Footers Header / Footer

Description

Page Number

Pages are sequentially numbered for each page of the report.

Starting Page:

Indicate the number for the first page of the report.

Date

Current date

Company Name

Fill in your Company Name

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Company Logo

Select an image file containing your company logo. Supported formats include ICO, BMP, JPG, JPEG, PNG.

Investigator

Fill in Investigator / Analyst name

Notes

Add any additional Notes about your project

Project Title

Fill in the Project Title. Note, this will also be shown in the Summary Table of the report.

Scenario

Name of current Scenario

Report File

File name of the report being generated

Vistro File

File name of the Vistro network

In addition and by default, the report contains the text “Generated with PTV Vistro” and the Vistro version number in the header. Report settings are saved in the network (*.Vistro) file. Note that the Mitigation reports are accessible from the Mitigation Workflow Task Table (see Chapter 9.1 Trip Generation on page 9410).

12.2 Vistro Report Contents The Vistro Report contains several tables and figures that can be broken down into the following: 

Analysis Results (tabular)



Analysis Figures (graphical)



Signal Warrants (tabular)



TIA Reports (tabular)



Signal Timing Output (graphical)



Fair Share Report (tabular)



Fair Share Report (graphical)

12.3 Analysis Results The analysis results are summarized and provided in a series of tabular outputs. Tables are generated for each intersection control type and analysis method in Vistro. The various tabular outputs from Vistro are presented below.

12.3.1 Intersection Analysis Summary Report The Intersection Analysis Summary report (Figure 40: Intersection Analysis Summary Report) consists of a summary table that presents the following items:

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

Intersection ID



Intersection Name



Control Type



Analysis Method



Identification of Worst Movement



Intersection V/C



Intersection Delay



Intersection LOS

Figure 40: Intersection Analysis Summary Report

12.3.2 Intersection Level of Service Report The Intersection Level of Service report presents the details of the level of service (LOS) calculations for each analysis intersection. These reports include several sub-sections, including: 

Summary information



Intersection Setup



Volumes



Intersection Settings



Phasing & Timing



Movement, Approach & Intersection Results

This is a complete report of input and output.

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12.3.2.1 Summary Information The first section of the Intersection LOS report presents summary level information about the intersection characteristics, parameters and analysis results (Figure 41: Summary Information) . Figure 41: Summary Information

12.3.2.2 Intersection Setup The next section reports the intersection setup information (Figure 42: Intersection Setup) . Figure 42: Intersection Setup

12.3.2.3 Volumes Following, the volumes are reported (Figure 43: Volumes). Figure 43: Volumes

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12.3.2.4 Intersection Settings The next section documents the intersection settings (Figure 44: Intersection Settings) . Figure 44: Intersection Settings

12.3.2.5 Phasing & Timing The following section documents the phasing and timing (Figure 45: Phasing & Timing). Figure 45: Phasing & Timing

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12.3.2.6 Movement, Approach & Intersection Results The last section reports the movement, approach and intersection level results (Figure 46:). Figure 46: Movement, Approach & Intersection Results

12.3.3 Signal Warrants Report The Signal Warrants report presents the details of the determination of whether unsignalized intersections would meet the warrants for a traffic signal. The following volume-based warrants from the 2009 Manual for Uniform Traffic Control Devices (MUTCD 2009) are evaluated and reported based on the hourly volume factors defined in the “Report Nodes” tab for each unsignalized intersection: 

Warrant #1: Eight Hour Vehicular Volume



Warrant #2: Four Hour Vehicular Volume



Warrant #3: Peak Hour Vehicular Volume

The Signal Warrants report opens with a Warrants Summary. Figure 47: Movement, Approach & Intersection Results

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12.3.4 Trip Generation Summary Report The Trip Generation Summary provides a list of each Zone defined in the network and selected scenario and the associated data. The summary shows the total Added Trips and the total Removed Trips used in the analysis.

12.3.5 Trip Distribution Summary Report The Trip Distribution Summary provides a tabular summary of the % Share and number of trips distributed to and from each Zone between other Zones and Gates.

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12.3.6 Volume Summary Report The Volume Summary reports show the Total Analysis Volumes for the network and selected scenario at each intersection location.

12.3.7 Volume Details Report The Volume Details Report expands the volume summary to show the individual volume types used in the analysis, including: 

Final Base Volume



Net New Trips



Growth rate



Other



In Process



Future

The volumes are shown by movement as well as total volumes for each intersection.

12.3.8 Fair Share Report The Fair Share Report provides a summary of each Zone’s impact on each individual intersection, by turning movement. Three reports are included:

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

Fair Share Volumes



Fair Share % of Net New Site



Fair Share % of Total Analysis

12.3.8.1 Fair Share Volumes The Fair Share Volumes report provides a summary at each intersection of the volume associated with each Zone analyzed in the network.

12.3.8.2 Fair Share % of Net New Site This report shows the % of the Net New Site Trips associated with each Zone analyzed.

12.3.8.3 Fair Share % of Total Analysis This report shows the % of the Total Analysis volumes associated with each Zone analyzed.

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12.4 Graphical Reports The following graphical reports can be selected from the Reporting Dialog: 1. 2. 3. 4. 5.

Study Intersections Lane Configurations and Traffic Control Devices Traffic Volume Traffic Conditions Time Space Diagram

12.4.1 Study Intersections The study intersections figure shows the geographic location of the analysis intersections (i.e. intersection attribute “Analyze Intersection” has been “checked”). The intersections are referenced by their ID number (Figure 48: Study Intersections) . Figure 48: Study Intersections

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12.4.2 Lane Configuration and Traffic Control This figure presents the lane configurations and intersection control device icons (Figure 49: Lane Configuration and Traffic Control) . Figure 49: Lane Configuration and Traffic Control

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12.4.3 Traffic Volumes These figures display traffic volumes by type (Figure 50: Traffic Volumes) . There is one figure per traffic volume type, including: 

Base



In-Process



Net New Site



Other



Total

The report will generate a figure for every volume type that exists in at least one turning movement. Figure 50: Traffic Volumes

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12.4.4 Traffic Conditions The Traffic Conditions figure (Figure 51: Traffic Conditions) displays the following intersection results: 

Level Of Service (LOS)



Delay



Volume / capacity (v/c)

Figure 51: Traffic Conditions

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12.4.5 Time Space Diagram Time space diagrams figures are also reported (Figure 52: Time Space Diagram) . The route is displayed visually in the top half of the figure, and the time space diagram is depicted in the bottom half of the figure , either as “flowing off” or “arterial bands.” Figure 52: Time Space Diagram

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12.4.6 Fair Share The Fair Share Volumes, % Net New, and % Total Analysis are included with one figure per Zone showing the impacts at each intersection location.

12.5 Vissim Previewer Vistro includes a quick simulation preview through the Vissim Previewer. To start the previewer, go to Simulation > Preview in Vissim . A separate Vissim Preview window will open and start a simulation of the traffic conditions for the current network and selected scenario. The user can control the simulation speed and the view but cannot make any changes to the simulation or generate any simulation output. To perform a full simulation analysis, refer to the description in Section 14.1.2 PTV Vissim.

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Scenario Management

13 Scenario Management With Vistro, you can manage several scenarios in a single project file using the Scenario Manager. Vistro will maintain your Base Scenario and track the variations for additional scenarios that you define. After developing your Base network, add scenarios to represent various traffic conditions such as: 

Peak Hours;



Future Analysis Years;



Future Build Conditions;



And many others.

The Scenario Manager is conveniently located in the Menu Bar, as shown in Figure 53: Scenario Editor. Here, you can add and delete scenarios. The Scenario chosen in this window is the currently selected scenario for editing. Figure 53: Scenario Editor

13.1 Base Scenario When starting a new Vistro project, the network you build will be your Base Scenario. Once you have a Base Scenario, you can define additional scenarios such as Weekday AM Peak and Weekday PM Peak. The Base Scenario is the foundation for all other Scenarios; therefore, any changes made to the Base Scenario are perpetuated through all other Scenarios. This allows you to go back and make network, volume, or traffic control changes and apply them to all scenarios created.

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13.2 Creating Additional Scenarios You can create additional scenarios for your project by doing the following: 1. Click the down arrow in the Scenario selector box 2. This will expand the Scenarios dialog, as shown in Figure 54: Figure 54: Scenarios Dialog

3. Click on the

button in the Scenario Editor

4. Click the down arrow in the Scenario selector box to open the Scenarios dialog again and right-click and edit to rename the Scenario 5. To duplicate a Scenario, right-click on the Scenario and select Duplicate or click on the button 6. To delete a Scenario, right-click on the Scenario and select Duplicate or click on the button

13.3 Selecting the Active Scenario When multiple scenarios exist in the Vistro file, a scenario can be selected to be active by simply clicking the scenario name in the Scenario Editor:

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The active scenario is then displayed in the Scenario Selector:

13.4 Reporting by Scenario You can create a Vistro Report for each Scenario by simply selecting the Scenario for reporting and creating the report as described in Chapter 12 Report on page 128.

13.5 Mitigation by Scenario Likewise, you can evaluate mitigation options for intersections by Scenario. Again, select the Scenario and use the Mitigation Workflow as described earlier (see Chapter 11 Mitigation on page 126).

13.6 File Structure for Scenarios Beginning with Vistro 3, all Vistro files are project files. When a Vistro network is created by starting Vistro, or using File/New, a project called “base” is created in a unique temporary directory. Adding new scenarios then adds new modifications to the current project in this temporary directory. When a project is saved, it is zipped to one file with a *.vistro file extension. When a Vistro file is opened, this file containing the scenario project directory structure is unzipped in a temporary local directory and the project is opened there. In Vistro 1 and Vistro 2, when Scenarios were created, Vistro created a subfolder in the directory where your Vistro (*.vistro) file is saved. In this folder, a Vistro project file (extension *.vistropdb) was created.

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In addition, this folder contained additional subfolders with internal files used to track the changes made in each Scenario, as shown in Figure 55. Vistro Scenarios File Structure. Figure 55. Vistro Scenarios File Structure (Vistro 1 and Vistro 2 only)

These files do not need to be accessed directly. You only need to open the Vistro project file when opening the project in Vistro. To convert older Vistro files to the new file structure: 1. Select File > Open... 2. In the dialogue, select file type Old PTV Vistro Scenario Project Files (*.vistropdb). This will open the project in Vistro. 3. Select Save As… 4. Provide a new file name. The project is now stored as a Vistro 4 file (*.vistro).

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Import/Export

14 Import/Export Vistro allows you to exchange data between Vistro and a variety of other software, including PTV Visum and Vissim. File formats currently supported for Import / Export are listed below. Table 21: Supported Import and Export File Formats File Format

Import

Export

Vision Traffic Suite PTV Visum

X

PTV Vissim

X X

External Formats PTV Abstract Network Model (ANM)

X

X

Trafficware Synchro®

X

X

Transoft OTISS

X

X

SVG Volumes

X X

X

The following sections contain information about each of these file formats.

14.1 Vision Traffic Suite PTV Vistro is part of the PTV Vision Traffic Suite, which incorporates strategic planning, traffic operations, and traffic simulation into one integrated suite through three software platforms. By being part of the integrated suite, Vistro allows you to address and move between various levels of analysis. The integration with the specific software tools is described below.

14.1.1 PTV Visum Vistro supports import from and export to Visum. Vistro and Visum share a common data model, making the transfer of data between them seamless.

14.1.1.1 Import from Visum 1. Select menu File > Import > Visum. 2. Select a Visum version (*.ver) or network (*.net) file and click Open.

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14.1.1.2 Import in Visum 1. In Visum select menu File > Import > Vistro. 2. Select the Vistro file.

14.1.2 PTV Vissim Vistro supports export to Vissim, using the abstract network model (ANM). From a Vistro network, an abstract network model (ANM) file can be created which can then be imported into and edited in Vissim. 1. Select File > Export > ANM. 2. Define a file name and select Save. This will create an ANM (*.anm) file that can subsequently be imported into Vissim. 3. Import the file in Vissim. Modifications of the Vistro network can also be added later to a network previously exported and edited in Vissim. Only the parts affected by the Vistro modifications will be adjusted in the Vissim network using the Adaptive Import functionality in Vissim.

14.2 External Interfaces In addition to being part of the integrated Vision Traffic Suite, Vistro also has the ability to interface with external software platforms, as described below.

14.2.1 Abstract Network Model (ANM) The PTV Abstract Network Model (ANM) is an XML file format that allows access to both Visum and Vissim through a common data interchange format. This format allows other traffic planning and engineering software to interface with the Vision Traffic Suite, including Vistro. Vistro also supports export to the ANM format for expanded interchange capabilities with external software products. These models also serve as an intermediate network format for Visum and Vistro export to Vissim, as discussed in section 14.1.2 PTV Vissim on page 151.

14.2.2 Trafficware Synchro ® Vistro also supports import from and export to Synchro ®, via the Synchro ® Universal Traffic Data Format (UTDF) CSV (*.csv) file format for Synchro ® Versions 7 and 8.

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14.2.2.1 Import from Synchro ® 1. Select menu File > Import > Synchro ®… 2. In the resulting dialog, select a Synchro ® combined data (*.csv) file and select Open. Vistro will import all elements from the Synchro ® UTDF CSV file, including network geometry, volumes, turning movements, vehicle compositions, intersection control, and signal timing. NOTE: This feature does not support the import of data generated with Synchro ® version 6 or below.

14.2.2.2 Export to Synchro ® 1. Select menu File > Export > Synchro ®… 2. In the resulting dialog, provide a filename Synchro ® combined data (*.csv) file and select Save. 3. Open the combined data (*.csv) file in Synchro ®. Vistro will import all elements from the Synchro ® UTDF CSV file, including network geometry, volumes, turning movements, vehicle compositions, intersection control, and signal timing.

14.2.3 Transoft OTISS Vistro provides import and export functionality for the Transoft Online Traffic Impact Study Software (OTISS). This allows you to utilize the full power of OTISS to produce your trip generation for all of your zones and use the OTISS results to populate the Trip Generation table in Vistro. The OTISS import / export is accessible from the File > Import or File > Export menu items as well as from the icons in the upper right hand corner of the Trip Generation workflow panel table. 1. To use OTISS, first add the desired Zones to your Vistro Network and provide the Zone Name to help identify the Zone. 2. Once this is set up, export the Vistro file to OTISS. Then use your OTISS online subscription to import the Vistro file. In OTISS, you will see your Vistro project file and your Zones will be listed there. 3. Complete your trip generation calculations in OTISS. When this is complete, export the file OTISS file to Vistro. 4. Back in Vistro, import the OTISS file. The data from OTISS now populates your Trip Generation table.

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14.2.4 SVG File Vistro can export a screenshot of the network as an SVG file for viewing in a browser. 1. Select File > Export > SVG. 2. Define a file name and select Save. This will create an SVG (*.svg) file that can be opened in a browser.

14.2.5 Volumes Vistro can import and export turning movement volumes using a CSV (*.csv) file. In a typical workflow, a user would first define the intersection lane configurations for all intersections in the network and then use File > Export > Volumes… to export out the formatted CSV file. Then, using a spreadsheet tool such as Excel®, the user can populate the appropriate turning movement cells with the corresponding volumes. Afterwards, the user can import the CSV file containing the volumes using File > Import > Volumes… Vistro can import and export the following turn volume attributes: 

Base Volume Input



In-Process Volume



Diverted Trips



Pass-by Trips



Existing Site Adjustment Volume



Other Volume



Right-Turn on Red Volume

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Analysis Methods

15 Analysis Methods As described previously, Vistro provides intersection analysis for the following intersection types: 

Signalized;



Roundabouts



Two-way Stop Control; and



All-way Stop Control.

15.1 Signalized Intersection Analysis Methods The following intersection analysis methods are available in Vistro: 

Highway Capacity Manual 2010 (HCM 2010) for Signalized Intersections



Highway Capacity Manual 2000 (HCM 2000) for Signalized Intersections



Circular 212 Planning and Operations



Intersection Capacity Utilization Methods 1 and 2 (ICU1 and ICU2)

15.1.1 HCM 2010 for Signalized Intersections The signalized intersection methods from the Highway Capacity Manual (HCM) 2010 are implemented in Vistro. The signalized intersection methodology is documented in Chapters 18 and 31 of the HCM 2010. The methodology is described in brief summary here. The basic flow chart for performing capacity analyses for signalized intersections is displayed in Figure 56: HCM 2010 Signalized Intersections Methodology. Key inputs include the intersection geometry, volumes (counts or adjusted demand model volumes), and signal timing. The intersection geometry is deconstructed into lane groups, which are the basic unit of analysis in the HCM method. A lane group is a lane or set of lanes designated for separate analysis. Each intersection approach may have one or more lane groups. The volumes are then adjusted by peak hour factors or other volume adjustment factors. The saturation flow rates are then determined based on the ideal saturation flow rate and various adjustment factors. The capacity is then determined for each lane group by multiplying the saturation flow rate by the number of lanes and the green/Cycle ratio. After calculating the volumes and capacities for each lane group, various performance measures are calculated. These include average control delay per vehicle, the v/c ratios, the level of service and queues.

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The flow chart for conducting HCM 2010 signalized intersection analysis is shown in Figure 56: HCM 2010 Signalized Intersections Methodology: Figure 56: HCM 2010 Signalized Intersections Methodology (Taken from the Highway Capacity Manual 2010, Exhibit 18-11.) Pretimed

Actuated

Step 1. Determine Movement Groups and Lane Groups

Step 2. Determine Movement Group Flow Rate

Step 3. Determine Lane Group Flow Rate

Step 4. Determine Adjusted Saturation Flow Rate

Step 5. Determine Proportion Arriving During Green

Step 6. Determine Signal Phase Duration

Converge?

Step 7. Determine Capacity and Volume-to-Capacity Ratio

Step 8. Determine Delay

Step 9. Determine LOS

Step 10. Determine Queuing Step 1: Determine Movement Groups and Lane Groups Movement groups and lane groups are similar in meaning. There are differences between them when a shared lane is present on an approach with two or more lanes. The movement  PTV AG Feb-16

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Analysis Methods

group designation is useful for specifying input data. The lane group designation is useful for describing the calculations associated with the methodology. Movement groups are determined based on the following rules: 

Exclusive turning lane(s) serve as a movement group



Remaining lanes combine to serve as another movement group

A lane group is a lane or set of lanes designated for separate analysis. Each intersection approach may have one or more lane groups. The following are designations of lane groups: 

Exclusive left turn-lane(s)



Exclusive right turn-lane(s)



Exclusive through lane(s)



Shared left-through lane



Shared through-right lane



Shared left-right lane



Shared left-through-right lane

Step 2: Determine Movement Group Flow Rate

This step determines the flow rate for each movement group. A movement’s flow rate is assigned to a movement group if a turn movement is served by one or more exclusive lanes and no shared lanes. Any remaining approach flow is assigned to one movement group. The RTOR flow rate is subtracted from the right-turn flow rate, regardless of whether the right turn occurs from a shared or an exclusive lane. Step 3: Determine Lane Group Flow Rate This step determines the lane group flow rate. The lane group flow rate equals the movement group flow rate if there are no shared lanes on the intersection approach or the approach has only one lane. The lane group flow rate is computed by the procedure described in HCM 2010 Chapter 31 if there are one or more shared lanes on the approach and two or more lanes. This procedure is based on an assumed desire by drivers to choose the lane that minimizes their service time at the intersection, where the lane volume-to-saturation flow ratio is used to estimate relative differences in this time among lanes. Step 4: Determine Adjusted Saturation Flow Rate This step determines the adjusted saturation flow rate for each lane of each lane group. The base saturation flow rate input is used as a starting point, and is then multiplied by various factors that adjust the base saturation flow rate to reflect the specific conditions present on the approach.

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This procedure applies to lane groups that consist of an exclusive lane(s) operating in a pretimed protected mode, without pedestrian or bicycle interaction. The supplemental procedures described in HCM 2010 Chapter 31 are combined with those in this step to compute the adjusted saturation flow rate when other conditions are present. The adjusted saturation flow rate per lane for the subject lane group is calculated as: s = so fw fHV fg fp fbb fa fLU fLT fRT fLpb fRpb where: s = adjusted saturation flow rate (veh/h/ln), so = base saturation flow rate (pc/h/ln), fw = adjustment factor for lane width, fHV = adjustment factor for heavy vehicles in traffic stream, fg = adjustment factor for approach grade, fp = adjustment factor for existence of a parking lane and parking activity adjacent to lane group, fbb = adjustment factor for blocking effect of local buses that stop within intersection area, fa = adjustment factor for area type, fLU = adjustment factor for lane utilization, fLT = adjustment factor for left-turn vehicle presence in a lane group, fRT = adjustment factor for right-turn vehicle presence in a lane group, fLpb = pedestrian adjustment factor for left-turn groups, and fRpb = pedestrian –bicycle adjustment factor for right-turn groups. The details of the calculations of the saturation flow adjustment factors are described in detail in HCM 2010 Chapters 18 and 31. Step 5: Determine Proportion Arriving on Green The proportion of vehicles that arrive during the green and red signal indications affects the control delay and queues. Delay and queue size are smaller when a larger proportion of vehicles arrive during the green indication. The proportion of vehicles arriving on green for each lane group is calculated by: P = Rp (g /C ) where: P = proportion of vehicles arriving on green, Rp = platoon ratio, g = effective green time, C = cycle length. The effective green time g and cycle length C are known for pre-timed operation. If the intersection is not pre-timed, then the average phase time and cycle length must be calculated by the procedures described in the next step.  PTV AG Feb-16

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Step 6: Determine Signal Phase Duration The duration of a signal phase depends on the type of control used at the subject intersection. If the intersection has pre-timed control, then the phase duration is an input and this step is skipped. If the phase duration is unknown, then the pre-timed phase duration procedure in Section 2 of HCM 2010 Chapter 31 can be used to estimate the pre-timed phase duration. If the intersection has actuated control, then the actuated phase duration procedure in Section 2 of HCM 2010 Chapter 31 is used in this step to estimate the average duration of an actuated phase. It distinguishes between actuated, non-coordinated, and coordinated phase types. Step 7: Determine Capacity and Volume-to-Capacity Ratio The lane group volume-to-capacity ratio and the critical intersection Volume-to-Capacity ratio are calculated in this step. Lane Group Volume-to-Capacity Ratio: The capacity of a given lane group serving one traffic movement, and for which there are no permitted left-turn movements, is defined by: c = N s g/C where c = capacity (veh/hr) N = number of lanes in the lane group s = saturation flow rate (veh/hr/ln) g = effective green time (s) C = cycle length (s) HCM 2010 Chapter 31 provides a procedure for estimating the capacity for shared-lane lane groups or permitted left-turn operations, accounting for other factors that affect their capacity. The volume-to-capacity ratio for a lane group is defined as the ratio of the lane group volume and its capacity: X=v/c Where: X = volume-to-capacity ratio, v = demand flow rate (veh/hr), and c = capacity (veh/hr) Critical Intersection Volume-to-Capacity Ratio: The critical volume-to-capacity ratio, Xc, is another measure used for evaluating signalized intersections, and is computed by:

   ∗      Page 158/211

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Where: Xc = critical intersection volume-to-capacity ratio, C = cycle length (s), v/ (N*s)I = critical flow ratio for phase I , ci = set of critical phases on the critical path, and L = cycle lost time (s). Step 8: Determining Delay The delay calculated in this step represents the average control delay experienced by all vehicles that arrive during the analysis period. It includes any delay incurred by these vehicles that are still in queue after the analysis period ends. The control delay for a given lane group is computed by: d = d1 + d2 + d3 where d = control delay (s/veh), d1 = uniform delay (s/veh), d2 = incremental delay (s/veh), and d3 = initial queue delay (s/veh). Calculating Uniform Delay, d 1: The uniform delay is the delay expected given a uniform distribution for arrivals and no saturation. It also assumes one effective green period during the cycle and one saturation flow rate during this period. It is calculated as follows:

  0. 5  1  1  1  1, / where C = cycle length (s),

g = effective green time (s), and X = volume-to-capacity ratio

Alternatively, the HCM 2010 presents the “incremental queue accumulation” procedure for cases beyond the assumptions mentioned above, to allow more accurate uniform delay estimates for progressed traffic movements, movements with multiple green periods, and movements with multiple saturation flow rates (e.g., protected-permitted turn movements). The incremental queue accumulation procedure models arrivals and departures as they occur during the average cycle. Specifically, it considers arrival rates and departure rates as they may occur during one or more effective green periods. The rates and resulting queue size can be shown in a queue accumulation polygon. Refer to HCM 2010 Chapters 18 and 31 for details.

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Calculating Incremental Delay, d 2: The incremental delay term accounts for delay due to random variation in the number of arrivals on a cycle-by-cycle basis. It also accounts for delay caused by demand exceeding capacity during the analysis period. It is calculated as follows:

2  900    1    1  8       With

where T = analysis period duration (h), X A = average volume-to-capacity ratio, c A = average capacity (veh/h), k = incremental delay factor, and I = upstream filtering adjustment factor. Calculating Initial Queue Delay, d 3: The initial queue delay is the result of unmet demand at the start of the analysis period. If no lane group has initial queue, then the initial queue delay, d 3, is 0.0 seconds/vehicle. This value is set to 0 in the current implementation. If initial queue is present at the start of the analysis period, the equations in HCM 2010 Chapter 18 can be used to estimate the initial queue delay for the lane group. Calculate Delay for the Approach, d A: The average control delay for each approach to the intersection is a weighted average delay, where each lane group delay for the approach is weighted by the lane group demand flow rate. It is calculated by:

  ∑∑ 

Calculate Delay for the Intersection, d I: The average control delay for the intersection is also a weighted average delay, where each lane group delay for the intersection is weighted by the lane group demand flow rate. It is calculated by:

  ∑∑  Page 160/211

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Analysis Methods

Step 9: Determine LOS The LOS is determined for each lane group, approach and the intersection as a whole, based on the thresholds presented in Table 22: Intersection Level of Service (LOS) for HCM 2010 Signalized Method. Table 22: Intersection Level of Service (LOS) for HCM 2010 Signalized Method Level of Service (LOS) LOS A LOS B LOS C LOS D LOS E LOS F

Control Delay (s/veh)

≤> 1020 10 > 2035 >> 3555 5580 > 80

Step 10: Determine Queuing The HCM 2010 Chapter 31 describes a procedure for estimating the back-of-queue size and the queue storage ratio. The position of the vehicle stopped farthest from the stop bar during a cycle is the back of queue. The arrival pattern of vehicles and the number of vehicles that do not clear the intersection during the previous cycle affect the back-of-queue size. The proportion of the available queue storage distance that is occupied at the point in the cycle when the back-of-queue position is reached is defined as the queue storage ratio. The storage space overflows when this ratio exceeds 1.0, and vehicles may be blocked from moving forward by the queued vehicles. The back of queue size for a lane group is calculated by: Q = Q1 + Q2 + Q3 where Q = back-of-queue size (veh/ln), Q1 = first-term back-of-queue size (veh/ln), Q2 = second-term back-of-queue size (veh/ln), and Q3 = third-term back-of-queue size (veh/ln).

15.1.2 HCM 2000 for Signalized Intersections The signalized intersection methodology is documented in Chapter 16 of the HCM 2000. The basic flow chart for performing capacity analyses for signalized intersections is displayed in Figure 57: Signalized intersection capacity analysis flowchart. You input the intersection geometry, volumes (counts or adjusted demand model volumes), and signal timing. The  PTV AG Feb-16

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intersection geometry is deconstructed into lane (or signal) groups, which are the basic unit of analysis in the HCM method. A lane (or signal) group is a group of one or more lanes on an intersection approach having the same green stage. For example, if an approach has just one pocketed exclusive left turn and one shared through and right turn, then there are usually two lane groups – the left and the shared through/right. Figure 57: Signalized intersection capacity analysis flowchart

The volumes are then adjusted via peak hour factors, etc. For each lane group, the saturation flow rate (SFR), or capacity, is calculated based on the number of lanes and various adjustment factors such as lane widths, signal timing, and pedestrian volumes. Having calculated the demand and the capacity for each lane group, various performance measures can be calculated. These include, for example, the v/c ratio, the average amount of control delay by vehicle, the Level of Service, and the queues. Step 1: Lane volume calculation from the movement volumes This step distributes the movement volumes to lanes according to the user-defined geometry. The basic distribution rule is to distribute the volumes uniformly to the lanes while taking the input movement volumes into account. You can overwrite a lane's utilization share within its lane group, if applicable. Step 2: Volume adjustments by means of peak hour factors The input lane volumes are adjusted to represent the peak hour volumes through the peak hour factor (PHF ). The PHF is defined as:

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  4

Analysis Methods

Where vh = hourly volume (veh) v15 = peak 15-minute volume (veh) Then, vi = vg / PHF where vi = adjusted volume for lane group i vg = unadjusted (input) volume for lane group g PHF = peak hour factor (0 to 1.0) Step 3: Calculation of de facto lane groups left/though/right De facto lane groups are shared lanes with 100% of their volume making one movement. For example, if a lane group is a shared left and through lane, and 100% of the lane volume is making a left movement, then the lane group is converted to a de facto exclusive left lane group. Step 4: Calculation of the types of left turns The type of left turn needs to be determined in order to calculate the left turn adjustment factor. The left turn type is set as follows: 1. Fully controlled if all turns of an approach are conflict free during their green times. 2. Fully secured if the left turns are conflict free during green time. 3. Fully secured + permitted if during green time left turns are first fully secured and then permitted. 4. Permitted + fully secured if during green time left turns are first permitted and then fully secured. 5. Without left turn stage, all other cases. Step 5: Proportions of left turning and right turning vehicles by lane group The proportion of right and left turn volume by lane group needs to be calculated. PLT = vLT / vi PRT = vRT / vi where PLT = proportion left turn volume by lane group PRT = proportion right turn volume by lane group vi = adjusted volume by lane group  PTV AG Feb-16

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vLT = volume of left turning vehicles by lane group vRT = volume of right turning vehicles by lane group Step 6: Saturation flow rate calculation by lane group The saturation flow rate is the amount of traffic that can make the movement under the prevailing geometric and signal timing conditions. The saturation flow rate starts with an ideal capacity, which usually is 1,900 vehicles per hour per lane (vphpl) for HCM 2000. This number decreases due to various factors. The saturation flow rate is defined as: si = (so)(N ) • (f w) (f HV )(f g) (f p)(f a)(f bb)(f Lu)(f RT )(f LT )(f Lpb)(f Rpb) where si = saturation flow rate of lane group i so = ideal saturation flow rate per lane (usually 1,900 vphpl) N = number of lanes in lane group f w = factor for lane width adjustment f HV = Heavy vehicle adjustment factor f g = adjustment factor for approach grade f p = adjustment factor for parking f a = adjustment factor for the position of the link to city center (CBD true/false) f bb = adjustment factor for bus stop blocking f Lu = adjustment factor for lane usage f RT = adjustment factor for right turns f LT = adjustment factor for left turns f Lpb = adjustment factor for pedestrians and bicyclists on left turns f Rpb = adjustment factor for pedestrians and bicyclists on right turns First the description of the main calculation is described and then the various adjustment factors are calculated. Step 7: Calculation of actual green times The effective green time (or actual green time for a lane group) needs to be calculated next. The effective green time results as follows: gi = Gi + li gi = effective green time per lane group Gi = green time per lane group li = loss time adjustment per signal group Step 8: Capacity calculation per lane group Related to the saturation flow rate is the capacity. The saturation flow rate is the capacity if the movement has 100% of the green time (this means, the signal is always green for the

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movement). The capacity, however, accounts for the fact that the movement must share the signal with the other movements at the intersection, and therefore scales the SFR by the percent of green time in the cycle. The capacity of a lane group is then defined as follows: ci = si • (gi / C) where ci capacity i si saturation flow rate i C cycle time gi / C green ratio i Step 9: Calculation of the critical vol/cap ratio for the entire intersection The critical v/c ratio of intersections is defined below. The HCM method is concerned with the critical lane group for each signal stage. The critical lane group is the lane group with the largest volume/capacity ratio unless there are overlapping stages. If there are overlapping stages, then the maximum of the different combinations of the stages is taken as the max. For the description of this method, please refer to HCM 2000, page 16-14, or HCM 2010, page 18-41.

        where

X c = critical saturation (v/c ratio) per intersection = volume/capacity ratios for all critical lane groups C = cycle time L = loss time total of the signal groups of all critical lane groups Step 10: Mean total delay per lane group In addition to calculating the critical v/c per intersection, the mean delay per vehicle is calculated by the HCM method. The mean total delay is defined below. d i = d Ui PF + d Ii + d Ri where d i mean delay per vehicle for lane group d Ui uniform delay d Ii incremental delay (stochastic) d Ri delay residual demand PF permanent adjustment factor for coordination quality (see HCM 2000 "Signal coordination (Signal offset optimization)" on page 274)

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where d Ui uniform delay for lane group i g i effective (actual) green time X i = v/c volume/capacity ratio Step 10b: Calculation of the incremental delay for each lane group The incremental delay is the random delay that occurs since arrivals are not uniform and some cycles will overflow. It is calculated as follows:

Where d Ii incremental (random) delay for lane group i c i capacity for lane group i X i = v/c volume/capacity ratio T duration of analysis period (hr) (default 0.25 for 15 min) k i lookup value (HCM attachment 16 – 13) based on the controller type I i upstream filtering / metering adjustment factor (set to 1 for isolated intersection) Step 10c: Delay calculation for the residual demand per lane group The residual demand delay is the result of unmet demand at the start of the analysis period. It is only calculated if an initial unmet demand at the start of the analysis period is input ( Q). It is set to 0 in the current implementation. It is calculated as follows:

where d Ri residual demand delay for lane group i Qbi initial unmet demand at the start of period T in vehicles for lane group (default 0) c i capacity T duration of analysis period (hr) (default 0.25 for 15 min) ui delay parameter for lane group (default 0)

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t i duration of unmet demand in T for lane group (default 0) Step 11: Delay calculation for the approach The total delay per vehicle for each lane group can be aggregated to the approach and to the entire intersection with the following equations. The approach delay is calculated as the weighted delay for each lane group.

Where d A mean delay per vehicle for approach A d i delay for lane group i v i volume for lane group i Step 12: Delay calculation for the intersection The intersection delay is calculated as the weighted delay for each approach.

where d I mean delay per vehicle for intersection I d A delay for approach V A volume for approach Step 13: Level of Service calculation The level of service is defined as a value which is based on the mean delay of the intersection (Table 23: Intersection Level of Service (LOS) for HCM 2000 Signalized Method).

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Table 23: Intersection Level of Service (LOS) for HCM 2000 Signalized Method Level of Service (LOS)

Control Delay (s/veh)

LOS A LOS B LOS C LOS D LOS E LOS F

≤> 1020 10 > 2035 >> 3555 5580 > 80

Step 14: Mean queue length calculation per lane group Queue lengths are also calculated by the HCM 2000 method. The equation for the calculation of the mean queue length is as follows: Q = Q1 + Q2 Where Q = mean queue length – the maximum distance (measured in vehicles) that the queue extends on the average signal cycle Q1 = mean queue length for uniform arrival with progression adjustment Q2 = incremental term associated with random arrival and overflow to next cycle Step 14a: Calculation of the number of residual vehicles after cycle 1 Q1 represents the number of vehicles that arrive during the red stages and during the green stages until the queue has dissipated.

where PF 2 = progression factor 2 v i = volume of lane group i per lane C = cycle time g i = effective green time of lane group i X i = volume/capacity ratio of lane group i

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where PF 2 = progression factor 2 v i = volume per lane of lane group i C = cycle time g i = effective green time lane group i si = saturation flow rate for lane group i R P = platoon ratio – based on lookup table for arrival type Step 14b: Calculate second-term of queued vehicles, estimate for mean overflow queue

T = analysis period (usually 0.25 for 15 minutes) k = adjustment factor for early arrival Qb = initial queue at start of period (default 0) c i = capacity for lane group i k = 0.12 I • (si gi / 3600)0.7 for fixed time signal k = 0.10 I • (si gi / 3600)0.6 for demand-actuated signal I upstream filtering factor (set to 1 for isolated intersection) Step 15: Calculation of the queue length percentile After calculating the mean back of queue, the percentile of the back of queue is calculated as follows:

Where Q average queue length

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Saturation flow rate adjustment factors We now return to the calculation of the saturation flow rate which involves several adjustment factors. Step 6a: Calculate lane width adjustment factor

where

≥

f w = lane width adjustment factor W = mean lane width ( 8) (ft) Step 6b: Calculate heavy goods vehicle factor

where fHV = adjustment factor for heavy goods vehicles %HV = percentage of heavy vehicles per lane group EP = passenger car equivalent factor (2.0 / HV ) Step 6c: Calculate approach grade adjustment factor

where f g = adjustment factor for approach grade %G = approach grade as percentage (-6 % to +10 %) Step 6d: Calculate parking adjustment factor f P is calculated as follows:

where f p = parking adjustment factor (1.0 if no parking, else N = number of lanes in lane group

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≥

0.050)

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N m = number of parking maneuvers per hour (only for right turn lane groups) (0 to 180) Step 6e: Calculate adjustment factor for position to city center f a = 0.9 if link is in the city center ( CBD), otherwise 1.0 where f a = adjustment factor for position CBD indicates a central business district Step 6f: Calculate bus stop blocking factor

where fbb bus stop blocking adjustment factor ( N number of lanes in lane group

≥

0.05)

NB number of bus stop events per hour (does not apply to left turn lane groups) (0 to 250) Step 6g: Calculate lane utilization adjustment factor

where f Lu = adjustment factor lane utilization v g = unadjusted (input) volume for lane group g v gl = unadjusted (input) volume for lane with highest volume in lane group (veh per hour) For this adjustment factor, an HCM lookup-table is regarded (HCM 2000: table 10-23 on page 10-26. Step 6h: Calculate right turn adjustment factor

where

≥

f RT right turn adjustment factor ( 0.05)

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P RT proportion of right turn volume for lane group Step 6i: Calculate left turn adjustment factor The left turn adjustment factor is the most complex of the factors. The calculation is simple for protected left turns. However, if there is permitted phasing, then the equation is quite complex. It is as follows:

where f LT = adjustment factor for left turns P LT = proportion of left turn volume for lane group For permitted staging, there are five cases. When there is protected-plus-permitted staging or permitted-plus-protected staging, the analysis is split into the protected portion and the permitted portion. The two are analyzed separately and then combined. Essentially this means treating them like separate lane groups. Refer to the HCM for how to split the effective green times among the protected and permitted portions. 1. Exclusive lane with permitted phasing – use the general equation below 2. Exclusive lane with protected-plus-permitted phasing – use 0.95 for the protected portion and the general equation below. 3. Shared lane with permitted phasing – use the general equation below 4. Shared lane with protected-plus-permitted phasing – use the equation above for protected phasing portion and the general equation below for the permitted portion 5. Single lane approach with permitted left turns – use the general equation below The general equation for calculating f LT for permitted left turns is below. Note that this is not the exact HCM 2000 equation since there are a few different versions depending on the situation – shared/exclusive lane, multilane/single lane approach, etc. But the equation is similar regardless of the situation. This general equation is the equation for an exclusive left turn lane with permitted phasing on a multilane approach opposed by a multilane approach. The equation is basically the percentage of the time when lefts can make the turn times an adjustment factor. The adjustment factor is based on the portion of lefts in the lane group and an equivalent factor for gap acceptance time that is based on the opposing volume. The calculation of the percentage of the time when lefts can make the turn is a function of the opposing volume and their green time. The equation is as follows:

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where f LT = Global adjustment factor for left-turns f LTmin = Minimum value for adjustment factor g = Effective non-protected green time for left-turn lane group g u = Effective non-protected green time for left-turns crossing a conflicting flow P L = Share of left-turns using lane L E L1 =Through equivalent for non-protected left-turns (veh/hr/lane) (look-up value depends on conflict flow volume) g q = Effective non-protected green time , while left-turns are blocked completely and the spillback of the conflict flow is reduced g o = Effective green time for conflict flow N = Number of lanes in lane group

V olc = Corrected conflict flow per lane per cycle = N o = Number of lanes in the lane group of the conflict flow v o = Corrected conflict flow f LUo = Lane utilization factor for conflict flow qro = Opposing queue ratio = max[1 - Rpo • (go / C ), 0] (Rpo = look-up value depends on ArrivalType) t l = Loss time for left-turn lane group The opposing volume is calculated from the signal groups that show green while the subject lane group has green. To calculate the opposing volume for a subject lane group, the entire opposing volume is used even if there is an overlap. The permitted left movement calculation does not need to be generalized to 4+ legs since only one opposing approach is allowed. Step 6j: Calculate pedestrian adjustment factors for left and right turns The computation of the factors for left-turning and right-turning pedestrians and bicyclists is a considerably complex operation. It is performed in four steps. For the computation, the

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bicycle volumes of the legs are regarded and the pedestrian volumes of the crosswalks. A traffic flow has potential conflicts with two crosswalks on the outbound leg. These two crosswalks head for the opposite directions. NOTE: At a leg which is a channelized turn no conflicts occur between right turn movements and pedestrians. Step 1: Determination of the pedestrian occupancy rate OCC pedg . The pedestrian occupancy rate OCC pedg is derived from the volume. The following applies.

Here, v pedg is the pedestrian flow rate, v 1 pedg and v 2 pedg are the pedestrian volumes of the crosswalks, C is the cycle time of the signal control and g 1 p and g 2 p indicate the duration of the green for the pedestrians. NOTE: In the HCM 2000 it is implicitly assumed, that the green for t he left turn movements and the green for the pedestrians start at the same time. In Vistro, this is not the case, however. Thus, the following distinction of cases applies in Visum: If the pedestrian green time overlaps (or touches) the green or amber stage for vehicles, an existing conflict is assumed. In this case, the duration of the green of the pedestrian signal group is fully charged. Otherwise it is assumed, that there is no conflict. In this case, g p = 0 is assumed. Step 2: Determination of the relevant occupancy rate of the conflict area OCC r Here, three cases are distinguished: Case 1: Right turn movements without bicycle conflicts or left turn movements from oneway roads 



In this case, the following applies: OCC r = OCC pedg Decisive for left turns from one-way roads is, that there is no opposite vehicle flow. Case 2: Right turn movements with bicycle conflicts Here, straight turns of bicyclists are assumed.

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

Here, v bicg is the bicycle flow rate, v bic is the bicycle volume, C is the cycle time of the signal control, g is the effective green time of the lane group, and OCC bicg is the conflict area's occupancy rate caused by bicyclists. Case 3: Other left turn movements These are left turn movements which do not originate from a one-way road. Here, a distinction of cases is made for the values g q and g p. g q is the clearing time of the vehicle flow on the opposite leg, and g p is the green time for the conflicting pedestrians. The following applies gp = max(g 1 p, g 2 p) Case 3a: g q ≥ g p



In this case, the calculation is shortened and the following applies f Lpb = 1.0



Pedestrians and bicyclists are irrelevant here, since the left turn movements have to wait until the vehicle flow on the opposite leg is cleared. Case 3b: g q < g p The following applies

Here, OCC pedu is the occupancy rate of pedestrians after the clearance of the vehicle flow on the opposite leg, and OCC pedg is the pedestrians occupancy rate. Step 3: Determination of the adjustment factors for pedestrians and bicyclists on permitted turns A pbT Here, two cases are distinguished with regard to the values N turn – which is the number of lanes per turn – and N rec , which is the number of lanes per destination leg. Case 1: Nrec = Nturn 



Here applies A pbT = 1 - OCC r Case 2: Nrec > Nturn Here, vehicles have the chance to give way to pedestrians and bicyclists. The following applies A pbT = 1 - 0.6 • OCC r

Step 4: Determination of the adjustment factors for the saturation flow rates for pedestrians and bicyclists f Lpb und f Rpb. f Lpb is the adjustment factor for left turns, and f Rpb is the adjustment factor for right turns. The following applies: f Rpb = 1 - P RT • (1 - A pbT ) • (1 - P RTA) f Lpb = 1 - P LT • (1 - A pbT ) • (1 - P LTA)

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P RT and P LT represent the proportions of right turn and left turn movements in the lane group, and P RTA and P LTA code the permitted shares in the right and left turn movements (each referring to the total number of right turn and left turn movements of the lane group).

15.1.3 Circular 212 (Planning and Operations) The Circular 212 Planning Method and Operations Method are documented in the Interim Materials on Highway Capacity , Transportation Research Circular 212, January 1980 (Transportation Research Board). These methods consist of a critical movement analysis approach to capacity analysis.

15.1.3.1 Passenger Car Equivalents for Circular 212 The Circular 212 methods employ a passenger car equivalent (PCE) factor to factor up left turning volumes to account for the impact of opposing through traffic for approaches with permitted left turn phasing from a shared left-thru lane (Table 24: PCE for Circular 212 Methods). Table 24: PCE for Circular 212 Methods PCE Value

Opposing Volume

1.0

Up to 300

2.0

301 – 600

4.0

601 – 1000

6.0

1000+

15.1.3.2 Saturation Flow Rates The default saturation flow rates for the Circular 212 methods are shown in Table 25: Saturation Flow Rates for Circular 212 Methods. Table 25: Saturation Flow Rates for Circular 212 Methods Method

2 phase

3 phase

4+ phase

Circular 212 Planning

1500 veh/hr/lane

1425 veh/hr/lane

1375 veh/hr/lane

Circular 212 Operations

1800 veh/hr/lane

1720 veh/hr/lane

1650 veh/hr/lane

These saturation flow rates can be over-ridden by the user based on local values, if applicable.

15.1.3.3 Identification of critical movements The pair of critical movements for each street (consisting of opposite approaches) is determined based upon the volume/saturation ratio (V/S) for each movement as follows:

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For Split Phase Approaches (sometimes called Approach Phasing) The critical movement pair is the two opposite-approach movements with the highest volume/saturation ratio on each opposite approach. For Protected Phase Approaches The critical movement pair is the combination of left plus opposing through (or opposing right, if it is greater than the opposing through) that sums to the highest V/S ratio. For Permitted Left Phase Approaches The selection of critical movements varies by method: For the Operations Methods of Circular 212: The single most critical movement is selected for the street (looking at both street approaches). The maximum V/S (left, through or right) of both street approaches is selected. For Circular 212 Planning: The sum of the volume/saturation ratios for opposing through (or opposing right, if it is greater than the opposing through) and left movements are compared and the maximum is selected.

15.1.3.4 Intersection Volume-to-Capacity (V/C) Ratio and Level of Service (LOS) The intersection Volume-to-Capacity ratio, V/C, is calculated as the sum of the critical movements for each approach. The intersection LOS is determined from the V/C ranges shown in Table 26:Intersection Level of Service (LOS) for Circular 212 Methods. Table 26:Intersection Level of Service (LOS) for Circular 212 Methods Level of Service (LOS)

V/C

LOS A

0.000 – 0.6000

LOS B

0.601 – 0.700

LOS C

0.701 – 0.800

LOS D

0.801 – 0.900

LOS E

0.901 – 1.000

LOS F

> 1.000

15.1.4 ICU1 and ICU2 The Intersection Capacity Utilization (ICU) Method is similar to the Circular 212 Planning method (See Section 15.1.3 Circular 212 (Planning and Operations) on page 176) with the exception that the ICU method includes signal loss time in the calculation of the overall

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intersection volume/capacity ratio (see J. Gould, “Comparing the 1985 HCM and the ICU Methodologies”, ITE Journal, August 1990), and no PCE factors are applied. Jurisdictions using this method may use different assumed saturation flows per lane. The default saturation flows per lane for the ICU method have been set in Vistro to 1600 veh/hr/lane; however, this value can be over-ridden by users. Two ICU methods are included in Vistro. One method adds the percentage loss time per cycle to the V/S ratio. The other multiplies the V/S ratio by the percentage loss time. ICU1 is commonly used. The lost time for this method is expressed as a percentage of cycle length. The overall intersection V/C for this method is calculated as follows:

ICU 1 =

V Loss + S Cycle

where: ICU1 = ICU Method No. 1. V/S

= sum of critical movement volume /saturation ratios.

Cycle

= cycle length in seconds.

Loss = total intersection loss time in seconds. The ICU2 is based on material contained in an ITE Journal article in August 1990 by J. Gould. The equation is as follows:

where: ICU2 = ICU Method No. 2. V/S

= sum of critical movement volume /saturation ratios.

Cycle

= cycle length in seconds.

Loss = total intersection loss time in seconds. The results of the two methods are similar, and the choice will depend upon which method has been accepted by local jurisdictions. The intersection LOS is determined from the V/C ranges shown in Table 27: Intersection Level of Service (LOS) for ICU Methods.

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Table 27: Intersection Level of Service (LOS) for ICU Methods Level of Service (LOS)

V/C

LOS A

0.000 – 0.6000

LOS B

0.601 – 0.700

LOS C

0.701 – 0.800

LOS D

0.801 – 0.900

LOS E

0.901 – 1.000

LOS F

> 1.000

15.2 Roundabout Intersection Analysis Vistro provides two options for roundabout intersection analysis: 

HCM 2010 for Roundabouts



Transport Research Laboratory (TRL) Kimber Method for Roundabouts

15.2.1 HCM 2010 for Roundabouts The roundabout methodology from the HCM 2010 is implemented in Vistro. This methodology is documented in Chapters 21 and 33 of the HCM 2010. According to the HCM 2010, this methodology is similar to the methodology for two-way stop control intersections with a few key points of difference: 





Determining the conflict flows follows the geometry of the roundabout. The standard values for gaps differ due to changed visibility conditions. Also this calculation is performed on the basis of lanes, not on the basis of turns. With this method it is assumed that only one-leg and two-leg approaches exist. Furthermore it is also assumed that the circulating roadway does not have more than two lanes.

The calculation process is illustrated by Figure 58: HCM 2010 Roundabout Methodology:

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Figure 58: HCM 2010 Roundabout Methodology

The calculation method according to HCM 2010 consists of twelve consecutive steps. Here, the description is reduced to the most critical steps.

Step 1: Calculate flow rates (volumes) for each turn The turn volumes are converted by multiplying them with the peak hour factor for the 15 minute peak.

Step 2: Calculating traffic flows for each lane and conflicting volumes for each approach All calculations are based on the traffic flows and conflicting volumes at each approach. These flows are derived from the turn volumes (in Figure 59: Approach flows at a four-leg roundabout) for a roundabout with four approaches designated with v 1 to v12):

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Figure 59: Approach flows at a four-leg roundabout

For the distribution of the volumes to the lanes please refer to HCM 2010, pages 21-14 and 21-15. Example The flow from the south is the sum of turn volumes v 7 + v8 + v9. The conflicting flow which applies to this flow is however the sum v 1 + v2 + v10. This approach can be applied to roundabouts with a countless number of approaches. U-turns can also be considered in the same way, if you want to integrate them in the capacity calculation. If an approach has more than one lane, the total inflow is distributed on lanes. 1. If only one lane is permitted for left turns, its volume is the sum of all volumes of left turns. 2. If only one lane is permitted for right turns, its volume is the sum of all volumes of right turns. 3. The remaining volume is distributed to all lanes in such way, that they all have the same volume if possible.

Step 3: Capacity The capacity of an approach depends on various factors: the number of lanes per approach, the number of lanes in the roundabout, and whether a lane is a bypass lane. For each of the cases, predefined formulas can be used (HCM 2010, equations 21-1 to 21-7). This is the basic formula: c = 1130 * e-Bv

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Here, B equals 0.001 for one-lane and two-lane entry roads to single-lane roundabouts, and for single-lane approaches to two-lane roundabouts the value is 0.0007. Two-lane approaches to two-lane roundabouts use the following values for B: 0.00075 for the innermost (left) lane, and 0.0007 for the outer (right) lane. For bypass lanes with only one conflicting exit lane the value 0.001 is used, whereas 0.0007 is used if there are two conflicting exit lanes. Users with detailed knowledge of critical gaps and follow-up times can replace these formulas. For the control type ‚roundabout‘, critical gap and follow -up time are set by lane. Turn-related values of this attribute are not regarded. For the extended computation, the capacity is derived from the following data (HCM 2010, page 33-3): c = Ae-Bv

where C=

capacity in PCU/h

V=

conflicting flow in PCU/h

gapc =

critical gap in s

gapf =

follow-up time in s

Vistro uses the following standard values: 4 s for the critical gap and 3 s for the follow-up time. You can optionally overwrite both values by lane. Pedestrians have an impact on capacity. For a detailed description, please refer to HCM 2010, pages 21-16 and 21-17. To the turns, the approach capacity is distributed in proportion to the volume.

Step 4: Wait times The mean wait time on a lane of an approach arises from the following values:

d=

mean delay in s/PCU

c=

lane capacity in PCU/h

v=

lane volume in PCU/h

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T=

observation period in h

The mean delay of a turn is the volume-weighted mean of the mean delay of lanes used.

Step 5: Queue lengths The mean queue length on a lane of an approach arises from the following values:

where Q95 =

95% percentile of queue length in PCU

c=

lane capacity in PCU/h

v=

lane volume in PCU/h

T=

observation period in h

Step 6: Level of Service (LOS) LOS per lane of an approach is defined as a classification of the mean delay. Table 28: LOS per lane based on the mean delay LOS A

Mean Delay (s / PCU) 0 – 10

B

> 10 – 15

C

> 15 – 25

D

> 25 – 35

E

> 35 – 50

F

> 50

The HCM does not determine the calculation of the LOS per approach, turn or intersection. In these cases Vistro calculates the LOS on the basis of the volume-weighted mean delay. If the volume exceeds the capacity, the LOS is automatically set to F .

15.2.2 TRL Kimber Method for Roundabouts The Kimber roundabout methodology was developed by R.M. Kimber, (Kimber 1980), (Kimber, Hollis 1979), (Kimber, Daly 1986), which is also described in the British guideline TD 16/93 "The Geometric Design of Roundabouts". The method is based on the empirical

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study of numerous roundabouts and the statistical adjustment of a model which estimates capacities in dependency of the geometry. On the basis of numerous observations, this function was calibrated to British roundabouts, however the method is applied by some to applications in North America and other regions. Process shows the calculation process for roundabouts according to the TRL/Kimber method: Figure 60: TRL Kimber Roundabout Analysis Calculation Process

In Vistro, the geometry input parameters used with the TRL/Kimber method are described through in the intersection setup table after selecting roundabout as the control type. In order for the Kimber method to be active for analysis, the analysis method in the roundabout intersection setup table must be set to Kimber. This section describes the relevant Vistro geometry parameters to the Kimber method. The definitions of these parameters are illustrated in Figure 61: Description of the Node Geometry for the TRL/Kimber model, which has been taken from the DMRB guideline TD 16/93. For a better comparison with this guideline, the common English original attributes and abbreviations are specified in Table 29: Geometric input attributes according to Kimber method.

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Table 29: Geometric input attributes according to Kimber method Vistro Parameter Lane Width

Description

Not explicitly used in the Kimber calculation, but used to calculate entry width (see below).

Units

ft or m

Width of the travel lane. Default = 12 ft (3.7 m), Range = any real number No. of Lanes in Pocket

Not explicitly used in the Kimber calculation, but used to calculate entry width (see below).

Entry Lane Width

Width of the approach directly at entry across all lanes.

Entry Radius

(R) Radius of the entry on the specified approach. More specifically the radius which tangentially approximates to the outer circle of the roundabout and the outer boundary of the approach.

See Section 8.1 Intersection Setup (Geometry) on page 49 for full definition. ft or m

Default = sum of the approach lane widths. ft or m

Default = 50 ft (15.2 m); Range = 0 - 500 ft (152.4 m) Entry Angle

(Φ) Acute angle measured between the projected tangential path of an entering vehicle and the path of a circ ulating vehicle.

degrees

Default = 45 degrees; Range = 0 – 180 degrees Approach Half Width Flare Length

(V) Road width of the approach without any turn pockets.

ft or m

Default = 10 ft (3.1 m); Range = 5 - 50 ft (1.5 - 15.2 m) (L‘) Half of the Length of the approach segment between the points where Entry Lane Width and Approach Half Width are measured.

ft or m

Default = 60 ft (18.3 m); Range = 3 – 60 ft (0.9 – 18.3 m) Grade Separation

(SEP) Distance between approach and exit of the same node leg. For regular roundabouts specify 0 ft. With values > 0 you describe the approaches at expanded roundabouts where the approach is far away from the exit of the same leg.

ft or m

Default = 0; Range = 0 - 300 ft (91.4 m) Inscribed Circle Diameter

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(D) External diameter of the roundabout. For asymmetric roundabouts specify the radius related to the environment of the specified approach.

ft or m

Default = 75 ft; Range = 32.8 – 656.2 ft (10 – 200 m)

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Figure 61: Description of the Node Geometry for the TRL/Kimber model

An additional required input for the Kimber method is the KimberHollis c-factor (KVKimberHollisC) . This factor is used to calibrate the temporal variability of the inflow. This parameter is input in the Roundabout/Kimber control table under the parameter “KimberHollis c-factor”. Once the above parameters have been defined, the Kimber method is calculated per the following steps.

Step 1: Traffic flows and conflicting volumes for each approach All calculations are based on the traffic flows and conflicting volumes at each approach. These traffic flows are derived from the volume turning movement inputs. All volumes are expressed in passenger car units (PCU).

Step 2: Approach capacities For roundabouts with RDistanceExit = 0, the following applies:

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where Cap = approach capacity in PCU/h qc = conflicting flow in PCU/h k = 1 - 0,00347 • (Φ - 30 ) - 0,978 • [(1/r) - 0.05] F = 303 x f = 0.21 t (1 + 0.2 x) t = 1 + .5 / (1 + M) M = e(D - 60)/10 x = v + (e - v) / (1 + 2 S) S = 1.6 (e - v) / L‘ The remaining variable descriptions refer to the attributes of the geometry description found in Table 29: Geometric input attributes according to Kimber method. For the case of roundabouts with RDistanceExit > 0, the following capacity calculation applies: Cap =1.004F - 0.036SEP - 0.232 qc + 14.35 - f qc(2.14 - 0.023 qc) where all sizes as above, however Cap and qc in PCU/min. The resultant approach capacity is written to the capacity parameter in PCU/h found in the control table.

Step 3: Queue lengths The queue length of an approach results from the Kimber and Hollis formula (Kimber, Hollis 1979), (Kimber, Daly 1986).

where L = expected queue length at the end of the observation period in PC units µ = approach capacity in PCU/h

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T = length of the observation period in h L0 = initial queue length(in Vistro always 0) C = Variation factor KVKimberHollisC v = approach volume in PCU/h ρ = v / µ = Saturation Vistro uses the formula modified in (Kimber, Hollis 79) for increased accuracy. The mean queue length an approach is saved in the parameter Queue Length.

Step 4: Delays The mean control-based wait time per approach results from the Kimber and Hollis formula (Kimber, Hollis 1979), (Kimber, Daly 1986).

where d = mean permitted delay in the observation period in s/PCU µ = Approach capacity in PCU/h T = length of the observation period in h L0 = initial queue length (in Vistro always 0) C = Variation factor KVKimberHollisC v = approach volume in PCU/h ρ = v / µ = Saturation The mean permitted delay an approach and is saved in the parameter Delay. Vistro evaluates, like in Step 3, the increased accuracy modified formula by Kimber and Hollis.

Step 5: Level-of-Service (LOS) The concept of LOS is not mentioned in the Kimber model. For consistency, Vistro defines a LOS per approach using the HCM 2010 unsignalized LOS delay thresholds classified with the Kimber mean permitted delay results (Table 35:Level-of-Service (LOS) Criteria for the AWSC Intersection Analysis). Vistro calculates the LOS of the entire intersection accordingly, on the basis of the volume weighted mean delay of all approaches.

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Table 30: LOS Based on the Kimber Mean Delay and HCM Unsignalized Thresholds LOS A

Mean Delay (s/PCU) 0 - 10

B

>10 - 15

C

>15 - 25

D

>25 - 35

E

>35 - 50

sF

>50

15.3 Two-Way Stop Control (TWSC) Intersection Analysis Two-way Stop Control (TWSC) intersection analysis is done using either the HCM 2010 or HCM 2000 methodologies for TWSC. The methodology is generally the same, as described below, with the key elements of HCM 2010 highlighted. The methodologies are documented in the HCM 2010 (Chapter 19) and HCM 2000 (Chapter 17).

15.3.1 HCM 2010 and HCM 2000 The operation of the Two-way Stop-controlled (TWSC) intersections is explained as an interaction between vehicles on major and minor movements. In HCM capacity analysis, the gap acceptance model and empirical models have been developed to describe this interaction. As shown in Table 31: Level-of-Service (LOS) Criteria for the TWSC Intersection Analysis., level of service (LOS) for TWSC intersection is determined by the computed control delay for the minor movement because major-street through vehicles (vehicles on priority movement) are assumed to experience zero-delay. Table 31: Level-of-Service (LOS) Criteria for the TWSC Intersection Analysis Control Delay

LOS by Volume-to-Capacity Ratio

(s / vehicle)

v/c ≤ 1.0

v/c > 1.0

0 – 10

A

F

> 10 – 15

B

F

> 15 – 25

C

F

> 25 – 35

D

F

> 35 – 50

E

F

> 50

F

F

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This part of the manual describes the details on the TWSC intersection capacity analysis; however, for further details on each computation step, it is recommended to refer to HCM 2010 Chapter 19. Most of the TWSC intersection can be analyzed correctly with the exception of accounting for upstream traffic signals, which will be incorporated in Vistro in the future. The TWSC intersection capacity analysis consists of five (5) steps as illustrated in Figure 62: HCM TWSC Analysis Methodology. Figure 62: HCM TWSC Analysis Methodology

The following subsections provide the details on each computation step for the TWSC intersection capacity analysis with HCM 2010.

Step 1: Movement priorities set up (HCM 2010) The priority for each movement at the intersection needs to be identified to designate the appropriate rank of each movement for next step. The priority (rank) of each movement for both four-leg intersection and T-intersection illustrated in Figure 63: Priority Ranks.

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Figure 63: Priority Ranks 4-leg intersection:

3-leg intersection:

Step 2: Demand Flow Rate Calculation and Conflicting Flow Rate Determination For analysis of existing traffic conditions, peak 15-minute flow rate is converted to peak 15minute demand flow rate by:#

   Where

v i = demand flow rate for movement i (veh/h)

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V i = demand volume for movement i (veh/h) PHF = peak hour factor In addition to the demand flow rates, conflicting flow rates are calculated because conflicting flow rate is directly related to the availability of acceptable gaps which need to be guaranteed before vehicles on minor movements can enter the intersection. Figure 64: Conflicting Flow Rate Computation (2-lanes / 4-lanes / 6-lanes) illustrates the movements which are in conflict with selected minor movement and factors that need to be applied to calculate conflicting flow rate for each movement. To obtain conflict flow rate, flow rate of each conflict movement needs to be multiplied by the factors shown in parentheses, then can be added up. Note that three numbers in parentheses are the factors for two-, fourand six-lanes on major-street. Figure 64: Conflicting Flow Rate Computation (2-lanes / 4-lanes / 6-lanes) (a) Left-turn from Major

(b) Right-turn from Minor

(c) U-turn from Major

(d) Right-turn from Minor

(e) Left-turn from Minor

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NOTE: In HCM 2000, U-turns were not taken into consideration. If HCM 2000 needs to be used for the TWSC analysis, disregard U-turns.

Step 3: Critical Headways and Follow-up Headways Determination The critical headway is defined as the minimum acceptable headway that needs to be allowed for one vehicle on minor-street to enter the intersection without any safety issues. The time between the departure of the first vehicle and the extra time which needs to be allowed for second vehicle on minor-street to enter the intersection safely is defined as follow-up headway. Both critical headway and follow-up headway can be computed from base critical and followup headways shown in Table 32: Base Critical Headways for TWSC Intersections and Table 33: Base Follow-Up Headways for TWSC Intersections. Table 32: Base Critical Headways for TWSC Intersections Base Critical Headway, t c,base (s) Vehicle Movement Two Lanes

Four Lanes

Six Lanes

Left-turn on Major Street

4.1

4.1

5.3

U-turn on Major Street

N/A

6.4

5.6

Right-turn on Major Street

6.2

6.9

7.1

Through traffic on Minor Street

6.5

6.5

6.5

Left-turn from Minor Street

7.1

7.5

6.4

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Table 33: Base Follow-Up Headways for TWSC Intersections Base Follow-Up Headway, t f,base (s) Vehicle Movement Two Lanes

Four Lanes

Six Lanes

Left-turn on Major Street

2.2

2.2

3.1

U-turn on Major Street

N/A

2.5

2.3

Right-turn on Major Street

3.3

3.3

3.9

Through traffic on Minor Street

4.0

4.0

4.0

Left-turn from Minor Street

3.5

3.5

3.8

Starting from base critical and follow-up headways, different adjustments which are specific to each movement are made:

Where

,  ,,  ,,  ,,   ,

t c,x = critical headway for movement x (s); t f,x = follow-up headway for movement x (s) t c,base = base critical headway (s); t f,base = base follow-up headway (s); t c,HV = adjustment factor for heavy vehicles (1.0 for major street with one lane in each direction; 2.0 for major streets with two or three lanes in each direction) (s);

t f,HV = adjustment factor for heavy vehicles (0.9 for major streets with one lane in each direction, 1.0 for major streets with two or three lanes in each direction);

P HV = proportion of heavy vehicles for movement (expressed as a decimal); t c,G = adjustment factor for grade (0.1 for right-turn movement from minor-street; 0.2 for leftturn and thru movement from minor-street)

G = percent grade (%); and t 3,LT = adjustment factor for intersection geometry (0.7 for minor-street left-turn movement at T-intersections; 0.0 otherwise) (s). NOTE: In HCM 2000, Critical gap and Follow-up time are used instead of Critical headway and Follow-up headway.

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Step 4: Capacity Computation The capacity of a movement is computed in following three steps: 1) calculate potential capacity, 2) compute capacity adjustment factors for minor-street movements, and 3) apply capacity adjustment factors and compute movement capacities. The potential capacity of each movement is computed based on the gap acceptance model which requires the critical headway and the follow-up headway as input data:

−  / ,  ,   ,  , 1−,,/ Where

c p,x = potential capacity of movement x (veh/h) v c,x = conflicting flow rate for movement x (veh/h) t c,x = critical headway for minor movement x (s) t f,x = follow-up headway for minor movement x (s) Rank 1 major-street movements are assumed to be unimpeded by any other movements with lower rank and also are not required to compute potential capacity. However, the potential capacity for the movements which are categorized as Rank 2, 3, and 4 needs to be computed and adjusted with factors which incorporates following aspects: 

Probability of queue free state for selected movement



Pedestrian impedance

Table 34:Capacity Adjustment Factors shows the list of equations which can be used to compute the capacity adjustment factor for each movement except for Rank 1 movements. Note that the Rank1 movements are assumed to be experiencing zero-delay; therefore, Vistro will not provide a capacity data for Rank 1 movements. In addition to capacity adjustment factor for each movement, the adjustment factors for the pedestrian impedance are computed as necessary. Table 34:Capacity Adjustment Factors Movement Left-turn from Major Right-turn from Minor

U-turn from Major

Thru on Minor

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Rank

Capacity Adjustment Factor

2

N/A

2

  ,  1 ,  ,   ∏ ,  ∏1 

2

3

N/A

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Left-turn from Minor

Pedestrian Impedance

4

N/A

where,

       (,)  0.65    3  0.6√ ′  1 ,           3,600

f = capacity adjustment factor k = rank 3 movement v j = flow rate of movement (veh/hr)

j = rank 2 movement l = rank 4 movement C m,j =

movement capacity of movement j

P 0,j = Probability of queue-free state for conflicting movement

p’ = Adjustment to the major-street left, minor-street through impedance factor p’’ = (p0,j)(po,k) f pb = pedestrian blockage factor w = width of the lane the minor

movement is negotiating into (ft)

v x = number of pedestrians S p = pedestrian walking speed (3.5 ft/s)

The potential capacity for the subject movement is adjusted by the factors (probability of queue-free state for conflict movement and pedestrian impedance) computed by equations above. If there are more than one conflict movement and/or conflicting pedestrian crossing, all applicable factors need to be multiplied to the potential capacity to take combined impact into consideration.

,  (,)  Where

c m,x = capacity of the shared lane (veh/h) c p,x = flow rate of the y movement in the subject shared lane (veh/h) c m,y = movement capacity of the y movement in the subject shared lane (veh/h) The capacity calculation so far assumes that each movement operates on exclusive lanes. When more than one movement shares the same lane (shared lane), the combined capacity of the shared lane is calculated:

  ∑∑, Where

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c m,y = movement capacity of the y movement in the subject shared lane (veh/h)

Step 5: Delay and 95th Percentile Queue Length Computation Average control delay for the subject minor movement is a reflection of the degree of saturation. The delay of each movement is estimated by:

3600        3600, 900 ,  1  ,  1  ,450 , 5 [ ] Where

d = control delay (s/veh) c m,x = capacity of movement x (veh/h),

v x = flow rate for movement x (veh/h) T = analysis time period (h)

Once the delay for each movement is estimated, the delay data for the approach and the intersection can be computed as the weighted average of the control delay for each movement. As stated earlier, Rank 1 movements are assumed to experience zero-delay. However, there are cases when left-turn vehicles on major-street are blocking through and right-turn movement on major-street (Rank 1 movements). Therefore, it is necessary to have additional equation to capture the delay of the Rank 1 vehicles which are blocked by lower rank vehicles. The average delay to Rank 1 is computed:

∗ ), ,  > 1 1  ( ,   { (1 ,,∗ ),,   1 Where

d Rank1 = delay to Rank 1 vehicles (s/veh) N = number of through lanes per direction on major street p* 0,j = proportion of Rank 1 vehicles nor blocked d M,LT = delay to major left-turning vehicles v i,1 = major-street through vehicles in shared lane (veh/h) v i,2 = major-street turning vehicles in shared lane (veh/h) Queue length is one of the important measures of effectiveness for unsignalized intersections. The 95th percentile queue length for the minor movement at TWSC intersection during the 15-minute peak period is estimated:#

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3600               ,   ,    ≈ 900 ,  1 ,  1  150 3600 ,  [ ]

Q95 = 95th percentile queue (veh) c m,x = capacity of movement x (veh/h),

v x = flow rate for movement x (veh/h) T = analysis time period (h)

15.4 All-Way Stop Control (AWSC) Intersection Analysis All-way Stop Control (AWSC) intersection analysis is done using either the HCM 2010 or HCM 2000 methodologies for AWSC. The methodology is generally the same, as described below, with the key elements of HCM 2010 highlighted. The methodologies are documented in the HCM 2010 (Chapter 20) and HCM 2000 (Chapter 17).

15.4.1 HCM 2010 and HCM 2000 The All-way Stop-controlled (AWSC) intersection analysis in HCM 2000 and 2010 is an iterative process until the solution converges. The analysis model is checking for all possible combinations vehicle’s existence at each approach and estimate the probability of each combination occurring at the intersection. As shown in Table 35:Level-of-Service (LOS) Criteria for the AWSC Intersection Analysis, level of service (LOS) for AWSC intersection is determined by the computed control delay for the intersection. Table 35:Level-of-Service (LOS) Criteria for the AWSC Intersection Analysis Control Delay

LOS by Volume-to-Capacity Ratio

(s / vehicle)

v/c ≤ 1.0

v/c > 1.0

0 – 10

A

F

> 10 – 15

B

F

> 15 – 25

C

F

> 25 – 35

D

F

> 35 – 50

E

F

> 50

F

F

This part of the manual describes the details on the AWSC intersection capacity analysis; however, for further details on each computation step, it is recommended to refer to HCM 2010 Chapter 20. The AWSC intersection capacity analysis is consist of five (5) steps as illustrated in Table 36: AWSC Analysis Methodology.

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Table 36: AWSC Analysis Methodology

The following subsections provide the details on each computation step for the AWSC intersection capacity analysis with HCM 2010.

Step 1: Lane flow rate computation (HCM 2010) For analysis of existing traffic conditions, peak 15-minute flow rate is converted to peak 15minute demand flow rate:

   Where

v i = demand flow rate for movement i (veh/h)

V i = demand volume for movement i (veh/h) PHF = peak hour factor Unlike the other control types, the AWSC intersection analysis requires lane-by-lane data for further analysis. Therefore, for multilane approaches, the flow rate for each lane needs to be determined. Typically an equal distribution of volume among lanes can be assumed unless there are lane utilization data available.

Step 2: Geometry group determination for each approach (HCM 2010) As shown in Table 37:Geometry Groups shows the details on each geometry group which is necessary for further departure headway computation step.

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Table 37:Geometry Groups Number of Lanes Intersection Configuration

Opposing Approach

Conflicting Approaches

Geometry Group

Subject Approach 1 1 1 1 1 1 1 2 3 3 3 1 1 1 2 2 3

0 or 1 0 or 1 2 2 2 0 or 1 3 0, 1, or 2 0 or 1 0 or 1 2 or 3 3 2 3 3 0, 1, 2, or 3 2 or 3

1 2 1 2 2 3 1 1 or 2 1 2 or 3 1 2 3 3 1, 2, or 3 3 2 or 3

1 2 3a / 4a 3b 4b

Four leg or T Four leg or T Four leg or T T Four leg

Four leg or T

Four leg or T

5

6

Step 3: Departure headway computation (HCM 2010) In order to compute departure headway, following parameters need to be obtained: 

Headway adjustment factor



Degree of utilization



Probability state of each combination



Probability adjustment factor



Saturation headway



Departure headway and convergence check

Headway adjustment factor The headway adjustment factor for each approach is computed:

ℎ  ℎ,  ℎ,  ℎ, where hadj =

headway adjustment factor (s)

P LT =

proportion of left-turning vehicles

hLT,adj =

headway adjustment for left-turns (s)

P RT =

proportion of right-turning vehicles

hRT,adj =

headway adjustment for right-turns (s)

P HV =

proportion of heavy vehicles

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hHV,adj =

headway adjustment for heavy vehicles (s)

Saturation headway adjustments for left-turns, right-turns, and heavy vehicles are shown in Table 38: Saturation Headway Adjustments by Geometry Group. Table 38: Saturation Headway Adjustments by Geometry Group Saturation Headway Adjustment (s) Factor Group 1

Group 2

Group 3a

Group 3b

Group 4a

Group 4b

Group 5

Group 6

LT

0.2

0.2

0.2

0.2

0.2

0.2

0.5

0.5

RT

-0.6

-0.6

-0.6

-0.6

-0.6

-0.6

-0.7

-0.7

HV

1.7

1.7

1.7

1.7

1.7

1.7

1.7

1.7

Degree of utilization With the lane flow rate from previous step and the assumed or calculated departure headway, the degree of utilization is computed:

  3,ℎ600 where

x =

degree of utilization

v=

demand flow rate for each lane (veh/h)

hd = departure headway (s, initial departure headway is 3.2 s) Probability state of each combination The probability state of each combination can be computed:

  ∏( )  () where P(i) = P(a j ) = a j =

probability for combination i probability of degree-of-conflict (DOC) for specific combination (i) and lane type (j) vehicle's presence on selected lane (1 or 0)

The probability of a j is shown in Table 39: Probability of a j.

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Table 39: Probability of a j a j

V j

P(a j)

(Vehicle’s existence)

(Volume on Conflicting Approach)

(Probability of DOC)

1

0

0

0

0

1

1

>0

x j

0

>0

1-x j

Table 40: Probability of Degree of Conflict Case (Two-Lane Approaches) presents the possible combinations of lane occupancies for two-lane approaches. A 1 indicates that a vehicle is occupying the lane and a 0 indicates that the lane is empty. NOTE: For the AWSC intersection analysis for three-lanes approaches, refer to the methodology in HCM 2010 Chapter 32 (32-42). HCM 2000 is not capable of analyze more than two-lane approaches. For the AWSC intersection analysis for three lanes approaches (only with HCM 2010), refer to the methodology for three-lane approaches in HCM 2010 Chapter 32 (32-42). Table 40: Probability of Degree of Conflict Case (Two-Lane Approaches) I

DOC Case

Number of Vehicles

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

1

0

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2

1 2 1

3 2

2

4

3

Opposing Approach L1

L2

0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 1 1 0 0 0 1 1 1 1 0 1 0 1 0

0 0 1 1 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 1 0 0 0 0 0 0 1 1 1 1 0 0 1 1

Conflicting Left Approach L1 L2 0 0 0 0 1 0 0 0 1 0 0 1 1 0 0 1 0 0 1 0 0 0 0 1 1 1 1 0 0 1 0 1 0 0

0 0 0 0 0 1 0 0 1 0 1 0 0 1 1 0 0 1 0 0 0 0 1 1 1 1 0 0 0 1 0 0 1 0

Conflicting Right Approach L1 L2 0 0 0 0 0 0 1 0 0 1 0 0 1 1 0 0 1 0 0 0 1 0 1 0 1 0 0 1 0 0 1 1 0 1

0 0 0 0 0 0 0 1 0 1 1 1 0 0 0 0 0 0 0 1 0 1 1 1 0 0 0 0 1 0 1 1 0 1

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Analysis Methods 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

4

3

5

4

5

6

1 0 1 0 1 0 0 0 1 1 1 1 0 0 1 1 0 1 1 0 1 1 1 1 1 1 0 1 1 1

1 0 1 1 0 1 1 1 0 0 0 0 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1 1 1

0 1 1 0 0 1 0 1 1 0 1 0 1 1 1 1 0 1 1 1 0 0 1 1 0 1 1 1 1 1

0 1 1 1 1 0 1 0 0 1 0 1 1 1 0 1 1 0 1 0 1 1 0 1 1 0 1 1 1 1

1 1 0 0 1 1 1 0 0 0 1 1 1 0 1 1 1 0 0 1 1 0 1 1 1 1 1 1 0 1

1 1 0 1 0 0 0 1 1 1 0 1 0 1 1 0 1 1 1 1 0 1 0 1 1 1 1 0 1 1

Probability adjustment factor Once the probability of each degree-of-conflict (DOC) case is computed, the probability adjustment is computed to account for the serial correlation in the previous computation. The probability adjustments are computed:

  1       =       =    =    = The probability adjustment factors are computed:

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Analysis Methods

 4      1  23 1        2 through AdjP4  23 3 5 through AdjP10  263     11 through AdjP37  6 27 38 through AdjP64  1270 where

α = 0.01 (or 0.00 if correlation among saturation headways is not taken into account) The adjusted probability for each combination can be computed:

     Saturation headway The saturation headway is computed by summing up the base saturation headway and headway adjustment factor.

ℎ  ℎ  ℎ

where hsi = hbase = hadj =

saturation headway (s) base saturation headway (s) saturation headway adjustment factor (s)

Departure headway and convergence check The departure headway of the approach is computed:

   ℎ  ′  ℎ  =

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Analysis Methods

The calculated values of the departure headway for each approach are compared with the initial values and if the values changed by more than 0.1 s, Step 3 needs to be repeated until the calculated values of departure headway for each lane converge. Table 41: Saturation Headway Values by Case and Geometry Group Case

Base Saturation Headway (s)

No. of Veh.

Group 1

Group 2

0

3.9

3.9

4.0

4.3

4.0

1

4.7

4.7

4.8

5.1

4.8

1

2

Group 3a Group 3b Group 4a Group 4b

Group 5

Group 6

4.5

4.5

4.5

5.3

5.0

6.0

6.2

6.8

2 ≥3 1

3

7.4 5.8

5.8

5.9

6.2

5.9

6.4

2

6.4

6.6

7.2

7.3

≥3 2 4

7.8 7.0

7.0

7.1

7.4

7.1

7.6

7.6

8.1

3

7.8

8.7

4

9.0

9.6

≥5 3

12.3 9.7

10.0

4

9.7

11.1

5

10.0

11.4

≥6

11.5

13.3

5

9.6

9.6

9.7

10.0

9.7

10.2

Step 4: Capacity and service time computation (HCM 2010) The capacity of each approach is computed by increasing the given flow rate on the subject lane while the flow rate on opposing and conflicting approaches is set as constant until the degree of utilization for the subject lane reaches 1. The service time required to compute control delay can be calculated:

  ℎ   Where

ts = service time (s) hd = departure headway (s) m = move-up time (s, 2.0s for Geometry group 1 through 4; 2.3 s for Geometry group 5 and 6)

Step 5: Delay and 95th percentile queue length computation The average control delay for each lane can be computed:

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Analysis Methods

    900 1    1  450ℎ 5 where d=

average control delay (s/veh)

x =

degree of utilization

t s =

service time (s)

hd =

departure headway (s)

T=

length of analysis period (h)

Then, the control delay for each approach and intersection is calculated by computing a volume-weighted average on each lane or approach. Queue length is one of the important measures of effectiveness for unsignalized intersections. The 95th percentile queue length for the minor movement at the AWSC intersection during the 15-minute peak period can be estimated:

 ≈ 900ℎ  1   1  150ℎ  Where

Q95 = 95th percentile queue length (veh)

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 PTV AG Feb-16

Vistro Shortcuts

16 Vistro Shortcuts Vistro provides you with shortcuts to further assist in building and evaluating your networks. Shortcuts are provided for navigating through the Network Window as well as entering data in the Workflow steps.

16.1 Network Window Shortcuts Table 42: Network Window Shortcuts lists shortcuts available from within the network window. Table 42: Network Window Shortcuts Network Task

Shortcut

Details

Zoom-in to rectangular window

Shift + mouse click and drag

Defines rectangular zoom

Zoom in

Scroll center mouse wheel forward

Zooms network in

Zoom out

Scroll center mouse wheel backward

Zooms network out

Panning

Click and drag center mouse wheel

Pans network

Keyboard arrow keys Insert Intersection

Right-click and select Insert Intersection and

Inserts chosen intersection

choose intersection type (Signalized, All-Way type at that location in the Stop, Two-Way Stop, Roundabout, Unknown) network Insert Zone

Right-click and select Insert Zone

Inserts Zone at that location in the network

Insert Gate

Right-click and select Insert Gate

Inserts Gate at that location in the network

Insert Multiple Nodes

Select node type from toolbox (Intersection,

Allows for quick insertion of

Zone, Gate), press and hold CTRL key on

multiple nodes of the same

keyboard and left-click to place nodes

type , without having to reselect from tool box

Copy intersections

CTRL+C, CTRL+V

Select the intersection in the network window and copy from the context menu (Right-click) or CTRL+C. Click in the network at the location to paste and paste the intersection via the context menu or CTRL+V

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Vistro Shortcuts

De-select current toolbox selection

Press Esc key on keyboard

Delete network item

Select item by mouse-click, and press Delete Allows for quick deletion of

Undo

De-selects toolbox selection

key on keyboard

network items

CTRL + z

Undoes most recent network action; can be performed for multiple actions

Re-do

CTRL + y

Redoes previously un-done action; can be performed for multiple actions

Save

CTRL + s

Saves file

Save File As...

CTRL + Shift + s

Calls up Save As… dialog to save file under a new name

16.1.1 Workflow Task Table Shortcuts Table 43: Workflow Table Shortcuts lists shortcuts available from within the workflow tables. Table 43: Workflow Table Shortcuts Workflow Task

Shortcut

Details

Move across data entry rows from left to right

Tab

Allows for quick editing of table rows

Select multiple cells across table rows

Shift + Arrow keys

Multi-Edit

Click and drag across multiple cells in a row;

Replaces current cell value with

enter value in subsequent Multi-Edit cell

value entered in Multi-Edit cell

Tab to cell and press space bar

Allows for expansion of drop-

Access drop-down menus

Allows for quick selection of multiple cells across rows

down menus Copy/Paste

CTRL+C, CTRL+V

Allows for copy/paste of cell values in the Trip Generation, Trip Distribution, Trip Assignment, and Network Optimization tables.

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 PTV AG Feb-16

Service & Support

17 Service & Support In this chapter, you can find more details about how to use the Online Help which is provided with Vistro. In addition, information on the License settings, how to contact the Vistro Technical Support hotline, and other services provided by PTV Group can also be found here.

17.1 Online Help The Online Help contains access to the PTV Vistro User Manual by going to the menu Help > PTV Vistro Help. Alternatively, this User Manual PDF is available by going to the menu Help > PTV Vistro Manual.

17.2 About PTV Vistro For details on your current Vistro installation you can call the License window via menu HELP – LICENSE INFO. This window displays the following: 

the Version number



the Build number



the Expiration Date of your license



the path of the Vistro installation

 PTV AG Feb-16

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Index

18 Index Additional Base Condition 11 Additional Scenarios 148 Analyze Queues and Spillbacks 14 Background Maps and Images 38 Base Scenario 147 Bing™ Maps 24 drawing 37 Calculate Intersection Level of Service 14 Circular 212 24 Common Parameters 49 critical movement volume 179 cycle length 179 Documentation 15 Drawing the Network 36 Evaluate the impacts of New Developments 14 Exit 27 Export 27, 151 to Vissim Microsimulation 13 File Structure 23 Future Condition 11 Genetic Algorithm 109 Geometry 49, 186 Getting Started 23 Global Settings 34 Graphical Reports 140 Graphics Selector 31 Hardware Requirements 22 HCM 2010/2000 24 ICU 24, 179 Import 27, 151 Installation 17 Intersection 25 Intersection approaches 15 Intersection Setup (Geometry) 49 Intersections Level of Service Report 132 Introduction 14 Kimber 24 Lane Configuration 142 Limits 15 Administrator privileges 17 Hardware Requirements 22 System Requirements 21 LOS Analysis Method Roundabouts 180

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LOS Analysis Methods 155 Manage Multiple Scenarios 14 Menu Bar 27 Mitigation 126 by Scenario 149 Mitigations 16 MUTCD 2009 25 Network 25 drawing 36 Network size 15 New 23, 27, 29, 30, 31 Open 27 Optimize Signal Timing 14 Overview 14 Print Report 27 Program Documentation 15 PTV Vissim Export 152 PTV Visum Export 151 PTV Visum Import 151 Quick Start 11 Quick-Vissim Tool View Animation 13 Reporting by Scenario 149 Report-Ready Tables and Figures 14 Reports 128 Formats 24 Roundabouts 55 Save 27 Save As 27 Scenario Management User defined scenarios 24 Scenarios Limits 16 Service and Support 210 Shortcuts Network Window 208 Workflow Task Table 209 Signal Optimization 12 Signal Timing Optimization 25 Signal Warrants Analysis 25 Signal Warrants Report 135 Signals 52 Limits 16 LOS Analysis Method 155 Software Overview 14 Starting Vistro 23

 PTV AG Feb-16

PTV Vistro 4 Manual

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