. Guidelin·es for Traffic Impact Assessment
Produc�d by
Road Engineering Association of Malaysia
In collaboration with
Jabatan Kerja Raya Malaysia
Extracts from this document may be reproduced except for commercial purposes, provided the source is acknowledged.
CONTENT
. Page
Foreword
IV
1.
Preamble
I
2.
Objectives of these Guidelines
1
3.
What is TIA?
2
4.
Scope of TIA
2
5.
TIA and the Legislation
3
6.
Basic Process and Organisation
4
7.
Parties Involved in TIA
5
Role of Developer
5
Role of Approving Authority
5
Role of TIA Assessor
6
8.
Accreditation of TIA Assessor
7
9.
When is TIATequired?
8
I 0.
Guidelines for Performing TIA
9
11.
Traffic Condition to be achieved by Mitigation Measures
9
12.
Validity Period of TIA Study
10
Appendix
11 - 23
Acknowledgements
24
II
CONTENT OF APPENDIX GUIDELINES FOR TRAFFIC IMPACT ASSESSMENT
.
Page Al
The General Approach
11
A2 Analysis of the Current Situation of the Study Area
12
A3
Trip Generation
13
A3.2
Non-site Traffic
13
A3.3
Site Traffic
14
Trip Generation
A4
,, '
14
Trip Distribution
16
Trip Assignment
18
Network Condition and Impact Analysis
19
A4.l
Definition of Terms
19
A4.2
Impact Analysis
20
A5
Mitigation Measures
21
A6
TIA Report
22
III
FOREWORD Road Engineering Association of Malaysia (REAM), through the cooperation and support of various road authorities and engineering institutions in Malaysia, publishes series of official documents on STANDARDS, SPECIFICATIONS, GUIDELINES, MANUAL and TECHNICAL NOTES which are related to road engineering. The aim of such publication is to achieve quality and consistency in the road and highway industry. The cooperating bodies are:Public Works Department, Malaysia Malaysian Highway Authority Institution of Engineers, Malaysia The Chartered Institution of Highway & Transportation (Malaysian Branch) The production of such documents is carried through several stages. The documents are initially compiled / drafted by the relevant Technical Committee and subsequently scrutinised by the relevant Standing Committee of REAM. They are finally endorsed by road authorities and practitioners of road engineering at a conference before publication. " '
The success of a Traffic Impact Assessment (TIA) study and the follow-up actions depend on the full cooperation of the Developer, Approving Authorities, as well as other professionals involved in the project. Guidelines are dynamic in nature. As more experience is gained through usage and more research done through time, appropriate modifications will be made to these GUIDELINES as and when necessary. Users of this document are most welcome to submit their views and suggestions for consideration.
ROAD ENGINEERING ASSOCIATION OF MALAYSIA 46A, Jalan Bola Tampar 13/14, Section 13, 40100 Shah Alam, Selangor, Malaysia Tel: 603 - 5513 6521 / 603 - 5513 6522 Fax: 603 - 5513 6523 Email :
[email protected] Website : http://www.ream.org.my
IV
1.
2.
PREAMBLE ..
1.1
New development invariably results in additional generated tri.J?S that affect the traffic condition of the existing road network. Each new development, or re development, will result in new traffic loads on the existing road network. Unless such new loading is properly studied and addressed; the road network will degenerate in capacity and efficiency, resulting in congestions and other negative impact on the environment. A common method tliat is used to address such problem is the TRAFFIC IMPACT ASSESSMENT (TIA). It is a systematic and scientific process whereby impact of the new generated traffic is assessed and mitigation measures prescribed. TIA provides a common platform on which both the developer and the approving authority work hand in hand to ensure that development of towns and cities is controlled in an 9rderly manner.
1.2
The guidelines contained herein are the current best practice in the work of TIA in Malaysia. They are, of course, subject to amendments and modifications from time to time resulting from the experience of their usage through time. This document should serve as the standard reference material for developers, TIA practitioners and the approving authorities. For eas� of reference, the term "these GUIDELINES", wherever it appears herein, means this whole document inclusive of the Appendix.
OBJECTIVES OF THESE GUIDELINES The objectives of these GUIDELINES are: •
To achieve uniformity in the practice of TIA in the country;
•
To set the best practice of TIA;
•
To standardise the preparation of TIA reports;
•
To provide the necessary technical links with the Environmental Impact Assessment and the Road Safety Audit; and
•
To provide a basis for approving authorities in assessing and apportioning a developer's contribution to road infrastructure improvements.
1
i' 3.
4.
WHAT IS A TIA? 3.1
TIA is an important tool used to determine the impact of tn;ffic generated from a proposed site development project (upon full development) on the surrounding road and transportation systems. It identifies the need for mitigation measures for a transportation system to reduce ·congestion, as well as to maintain or improve road safety. Although TIA does not replace area-wide or regional transportation study, they provide the authorities, planners and developers a framework in making critical land use and site planning decisions regarding traffic and transportation issues. Local Authorities may also use TIA as basis for assessing and apportioning a developer's contribution to road improvements.
3.2
Traffic should be one of the major considerations in the planning of new developments or upgrading of existing developments. TIA should start at the early planning stages of a project, including site selection stage. Early participation of TIA Assessor will contribute towards the preparation of a more responsive and cost-effective site plan. The developer should have TIA undertaken prior to submitting his development project plan to the approving authority. He needs to communicate with the approving authority to obtain specific TIA requirements.
SCOPE OF TIA Setting the scope for TIA allows for appropriate consideration of the data to be collected, area to be studied and methodology to be adopted. The scope of a TIA should contain at least the following key elements: •
Definition of the study area/boundary.
•
Determining existing traffic pattern, which includes primary and secondary data collection.
•
Information on land use and development in surrounding area of project.
•
Trip forecasting with sequential steps of trip generation, trip distribution and trip assignment.
•
Analysis of impacts of projected generated traffic in area of study.
•
Mitigation measures for all negative impacts.
2
5.
TIA AND THE LEGISLATION 5.1
Road Transport Act 1987, Act 333 Section 85(1) states that: No person shall:(a) (b) (c)
construct any access road (including paths, driveways or other means of access, whether public or private) to join any road: construct a drain to join a drain constructed alongside a road; carry out any works of any description in, upon, over or under any road,
unless plans containing details of the layout thereof (including such particulars as may be prescribed) have been submitted to and approved by the Minister charged with the responsibility for works in relation to a Federal road, or the appropriate authority in relation to a road other than a Federal road, and the Minister or the appropriate authority, as the case may be, may refuse such application or allow it on such conditions as he or it may impose. And subsection (8) further states that: The Minister or the appropriate authority, as the case may be, may make rules to regulate and control the carrying out or construction of any works referred to in subsection (1). It is quite clear, from the above Road Transport Act that submission would have to be made and approval sought from the appropriate approving authorities before any connection or change to an existing road system can be made. . At the same time, the responsibilities to regulate and control such activities -0r works rest with the designated authorities as well. TIA is one of the bases that will assist the authority concerned in considering and approving the application. 5.2
According to the guidelines entitled "Penambahbaikan Sistem Penyampaian Prosedur dan Proses Cadangan Pemajuan Serta Perlaksanaan Pusat Setempat" published by the Ministry of Housing and Local Government, a developer, in submitting his application for planning permission, must include in his submission a document called Development Proposal Report (Laporan Cadangan Pemajuan). This Report is required under section 21A of the Town and Country Planning Act 1976 (Act 172). In the Guidelines for preparing the Development Proposal Report, the Town and Country Planning Department requires that a report on "Sistem laluan (lebuhraya, jalan utama) rizabnya serta ekses keluar masuk. Dari penemuan analisis bahagian ini dan befgantaung kepada saiz pemajuan, pihakberkuasa perancang tempatan boleh mengarahkan suata laporan 'Penilaian Kesan Trafik' disediakan,jika perlu. "These GUIDELINES will assist the approving authority in determining when a TIA is required and the details of report to be submitted. 3
I'
6.
BASIC PROCESS AND ORGANISATON 6.1
The general process in which TIA is involved in the application for Planning Permission is depicted in Figure 6.1. i,
6.2
TIA study shall only be carried out by an Accredited TIA Assessor.
Commencement of development planning
Developer to engage consultants, including TIA Assessor
Preparation of preliminary site layout plan
Carry out TIA Review and modify site layout plan where necessary
Finalise TIA report if layout plan is modified Include in Development Proposal Report (Laporan Cadangan Pemajuan) for submission to Approving Authority for Planning Permission If only mitigation measures are modified
>------.i TIA report returned to Developer with queries or comments Not acceptable
OK Approving Authority to proceed with approval process
Figure 6.1: TIA in Planning Permission Application Process
4
7.
PARTIES INVOLVED IN TIA 7.1
The main parties involved in the TIA Process are: (1) the Developer, who is the owner of the development or re-development project, or any party appointed by the owner to carry out the project on his behalf; (2) the Approving Authority, who can be the local authority or the respective road authority; and (3) the TIA Assessor, who must be an Accredited TIA Assessor.
Role of the Developer
7.2
The Developer shall be responsible for engaging an Accredited TIA Assessor to carry out the TIA for his development or re-development. Each new development or re-development proposal, which is expected to generate added vehicular trips exceeding the trigger level (refer to section 9.2), shall require a TIA report to be submitted together with the planning application.
7.3
The Developer shall liaise with the Approving Authority at the early stage of planning the development in order to ensure that the . type and scale of the proposal is suitable for the site under consideration. They must also liaise with road and transport authorities to demonstrate the traffic planning for the development and to identify any possible adverse traffic impacts. This process of early consultation with the approving authority is likely to save time and costs so that planning application could progress more speedily.
7.4
TIA Assessor should be appointed by the Developer at the planning stage of the project so that professional inputs with regards to traffic issues can be used by the planners/architects to develop the preliminary site/layout plans. This is important as it will avoid the undesirable situation where traffic requirements are incorporatedin the plan as an after-thought.
7.5
The Developer shall not interfere with the professional work of the TIA Assessor. The Developer shall implement the mitigation measures adopted by the Approving Authority.
Role of the Approving Authority
7.6
The term "Approving Authority" in these GUIDELINES refers to the local authority or the road authority, or both, whichever is applicable according to the situation. Each authority has its own power to control according to the law.
5
7.7
Approving Authority has a regulatory role in the TIA process in relation to land-use planning, and roads and transport infrastructure development. It should encourage pre-application discussions with the peveloper to steer the TIA study, including giving direction on sources of informa.tion, good practice i advice, and clear guidance on what the Developer may bt expected to provide in accordance with the transport strategy of the authoricy. TIA report will provide the Approving Authority with the relevant input, relating to traffic situation forecast and mitigation measures, for the Authority's consideration of the Developer's application for planning approval. Where appropriate, Approving Authority may use information in the TIA report as a basis for levying fees from developers for future infrastructure improvements.
7.8
Where an Approving Authority does not have in-house capacity to evaluate TIA reports, it may engage an independent Accredited TIAAssessor to evaluate the reports on its behalf.
Role of TIA Assessor 7.9
TIA Assessor can be an individual or a team of spe9ialists of a firm led by an Accredited TIA Assessor.
7.10 Traffic/Road Engineering Consultant of the development project who has been commissioned by the Developer to also carry out the TIA shall act independently in his role as TIA Assessors. By virtue of his profession, he shall directly or indirectly look after the interests of the general public and the local community. 7.11
TIA Assessor shall evaluate the planning and design of the project in promoting sustainable modes of transportation. Optimisation of road capacity by means of traffic managetr).ent measures should not be ignored.
6
8.
ACCREDITATION OF TIA ASSESSOR 8.1
Qualifications
'.
Any person who wishes to be accredited as a TIA Assessor must have the · · following qualifications: (a)
be registered with the Board of Engineers, Malaysia, as a Professional Engineer (Civil) for at least two (2) complete calendar years;
(b)
have at least ten (10) years total working experience (8 years for those with recognised post graduate qualifications);
(c) have a minimum of three (3) years experience in traffic engineering and a minimum of three (3) years experience in practical traffic impact assessment; and (d)
8.2
have attended a formal training course, and pass a Competency Test in Traffic Impact Assessment conducted by the tBoard of Engineers, Malaysia, or any organisation appointed by the Board to conduct the Test.
Registration of Accredited TIA Assessor Accreditation shall be carried out by the Board of Engineers, Malaysia. The Board shall maintain a current register of Accredited TIA Assessors. This register shall be accessible to the public.
7
.., \
9.
WHEN IS TIA REQUIRED? 9.1
General It is necessary to know when a traffic impact assessment ·is required. This is because not all developments will cause significant"· impact on their surroundings, especially those in the rural areas. Gene!ally, the criteria for warranting a TIA are as follows: • • • • •
9.2
When a development generates a specified number of peak hour trips; When a development generates a specified number of daily trips; When a development contains a specified number of dwelling units or specified built-up floor area; When a development occurs in a sensitive area; or When the Appropriate Authority considers it necessary under unusual situation.
Criteria and T rigger Levels
r The criteria and their corresponding trigger levels for warranting a TIA shall be: No.
Criteria
Trigger Levels
1.
Peak Hour Trip Generation (Commuter peak)
150 added vehicles per hour (2-Way)
2.
Off-Peak Hour Trip Generation (Generator peak occurs at the off-peak period)
200 added vehicles per hour (2-Way)
3.
Size of residential development
200 dwelling units
4.
Size of Commercial development
45,000 sq.ft. (gross floor area)
'
Note: Trip Generation Rates shall be based on the Malaysian Trip Generation
Manual published by the Highway Planning Unit of the MinistJy of Works, Malaysia.
A� the four (4) criteria must be tested, and if any one of the criteria for the proposed development reaches the prescribed trigger level, then a TIA study is required. However, in specific cases where the Approving Authority deems necessary, TIA may be imposed even if the trigger level has not been reached.
8
10. GUIDELINES FOR PERFORMING TRAFFIC IMPACT ASSESSMENT Traffic impact assessment shall be carried out in accordance with tlie guidelines given ·· in the Appendix. I.
11. TRAFFIC CONDITION TO BE ACIDEVED BY MITIGATION MEASURES '
BASELINE TRAFFIC CONDITION IN IAY** (LOS)
MINIMUM TRAFFIC CONDITION (LOS) AFTER MITIGATION MEASURES***
A B C D E F
D D D D D (exception E)* D (exception E)*
* ** ***
.
See sections 11.3 and 11.4 below. IAY means Impact Analysis Year. These requirements are applicable to road segments andi.each element of the intersections individually. See section A4. l in Appendix for definition of terms.
11.1 Traffic condition in the existing road network affected by the impact of the traffic from the new development will invariably become inferior to the Baseline Traffic Condition in IAY. Mitigating measures are supposed to restore the level of service of the existing roads to their baseline conditions. The minimum traffic condition to be achieved after mitigation measures are in place shall be as shown in the table above. 11.2 For roads with Baseline Traffic Condition in JAY at LOS of A, B, C or D, the minimum traffic condition after mitigation measures shall have LOS of D. LOS D is considered to be the lower bound level at which roads operate satisfactorily. Roads with LOS A, B or C can be allowed to take in more traffic until the LOS drops to D. 11.3 Where the Baseline Traffic Condition in JAY is at LOSE, the target mitigated LOS shall also be D. However, where site condition is very restrictive and the Approving Authority is convinced that the highest LOS achievable after mitigation measures is level E, the Approving Authority may consider allowing an exemption of the LOS D requirement. 11.4 Where Baseline Traffic Condition in IAY is at LOS F, it indicates that the existing road network, or part of it, is already below acceptable operating condition. New traffic should not be allowed to enter the road network. In general, Approving Authority should not consider approving any new development that will cause negative traffic impact to the existing network unless the developer can demonstrates that he can, and undertakes to, upgrade the existing roads to achieve the requirement in the table above. 9
12. VALIDITY PERIOD OF TIA STUDY If the time lapse between the dates of a TIA study and its suhmission is more than two (2) years, the TIA must be updated to reflect the latest traffic conditions of the locality. Not withstanding the abovementioned time lapse, th� A'j:>proving Authority may ask for an updated TIA whenever it deems necessary. . .·.
10
APPENDIX GUIDELINES FOR PERFORMING TRAFFIC IMPACT ASSESSMENT
Al. THE GENERAL APPROACH Al. 1 Traffic impact assessment must be performed professionally, always with public interest in mind. There must not be any predetermined objectives for which results and analyses are biased. The main objective of a TIA is to have a professional evaluation on the potep.tial impacts the proposed development may have on the transportation and traffic infrastructure in its vicinity. In the event of negative impacts being forecast, the TIA assessor must then propose ·the most appropriate mitigating measures to - achieve the requirements stated in Section 11. Al.2 The steps required in a TIA are generally as follows: demarcation of the study area (to consult and ob,tain approval from the Approving Authority); evaluation of the current traffi c condition of the road network within the demarcated study area; acquisition of information on the proposed and adjacent developments; estimation of the trips that will be generated upon completion and full occupation of the development; distribution and assignment of the generated traffic; analysis of the traffic and transportation condition of the study area upon completion and full occupation of the development; proposal of measures to mitigate the negative impacts; and production of the TIA report.
11
A2. ANALYSIS OF THE CURRENT SITUATION OF THE STUDY AREA A2. l The analysis of the current situation of the study area is.'important as it will serve as the base-line situation for determining the impacts,. of the proposed development. This base-line analysis should cover issues listed and elaborated in Table 2.1. Table 2.1: Data Required for the Base-line Situation Analysis Category
Data
Land use
- Current land-use (type and density) in vicinity of area - Estimated increase in land-use activity and size: - Anticipated development projects and planned completion dates, type and its density - Information pertaining the proposed development - Information from structure and local plans
r
Demographics
- Information on current and future demographic patterns (to include socio-economic information)
- The current traffic volume (daily and peak rates) - The traffic volume from several previous years (to get the trend of changes) Traffic Volume - Turning movements at junctions - Traffic volume fluctuation according to time and season. - Traffic volume forecast from other reliable source(s) - The current road characteristics (road type, width, number ap_d direction of lanes, exit and entry points, internal circulation, access control). - Road hierarchy and the controlling authority Transportation - Traffic signal locations, coordination and timing System - Local and regional plans - Public transport service and usage - Parking information - Road furniture - Other relevant information Other Traffic Data
- Origin and destination information - Modal split information - Road accident record
12
A2.2 Peak hours of travel activities in the study area have to be identified. It is during these peaks that impacts are studied. A 16-hour survey shall be carried out, usually from 6am to 1Opm. In less busy areas, especially where there are minimal night activities, a 12-hour survey may be acceptable. From either the 12- or 16- hour survey, the peak hours are identified. The survey should be conducted on a typical working weekday. •However, for proposed development with retail component having a gros� floor area of 100,000 sq. ft. or more, an additional survey should be carried out during weekend. The choice between Saturday and Sunday as weekend depends on the nature of development (i.e, which of these two days has more activity). Surveys should not be conducted in irregular seasons when travel pattern is not normal (e.g. during school �olidays, major festivals or religious festivities). Prior approval on the date of survey(s) from the Approving Authority must be obtained.
A3. TRIP GENERATION A3.1 Reliable estimate of the increase in traffic trips that will be caused by the proposed development is one of the key parameters that will determine the quality of the TIA. Generally, there are two categorie,$ of increased trips: NON-SITE TRAFFIC and SITE TRAFFIC. Each ot these will be dealt with below. A3.2 Non-Site Traffic A3.2.l
Non-site traffic includes all through trips of which neither the origin nor the destination is in the development site. This is usually the case for a development located by an existing main road, or whose access(es) leads to an existing main road. In ?rder to estimate the future through traffic in the existing main road, a historical trend in traffic volume changes of that road is needed. · The average annual growth is usually applied to the current volumes to estimate the future traffic volume for the Impact Assessment Year.
A3.2.2
Generally, the main source of this information is the "Road Traffic Volume Malaysia" (RTVM), published annually by the Highway Planning Unit (HPU) of the Ministry of Works. RTVM, however, does not include traffic data of roads under the jurisdiction of local authorities and rural roads. Information for such roads is usually unavailable, unless there is an initiative by the relevant road authority to collect them. TIA assessor should make necessary enquiry with the relevant road authority for possible availability of such information. Where such data is absolutely not available, or the available data is more than two years old, a traffic count shall be conducted and an estimated growth rate applied. The basis of estimating the growth rate shall be made known in the TIA report. 13
A3.2.3
It is important to establish as reliably as possible the baseline network traffic conditions (i.e. considering Non-Site traffic only) for the Submission Year (SY) and that for the �Impact Analysis Year (IAY). These JAY baseline traffi� c.onditions would represent the future scenario "without". the proposed development (i.e. with Non-Site traffic only). This scenario will be compared against a future scenario "with" the proposed development ( i.e. with Non-Site traffic and Site traffic taken together) to det�rmine the impact due to the proposed development.
A3.2.4
The IAY baseline n�twork conditions may be extrapolated by applying past growth rates (i.e. growth rates based on past trends) over the existing baseline traffic conditions. This approach assumes that the pattern and the rates of traffic growth in the study area in the future are similar to those of the past years. In the absence of a computerised traffic model which could account for both spatial and temporal variations, this approach of extrapolation may be accepted.
A3.2.5
A3.3
�
Where the JAY baseline network conditions can be derived from a computerised traffic model of the study area, method as given in A3.2.4 should not be used. A well-developed and correctly validated traffic model would be used to project the IAY baseline network conditions. The pattern of travel demand may be estimated by zone (spatial variation) and by time period (temporal) variation, such as morning peak, evening peak and off peak periods.
Site Traffic Trip Generation A3.3.l
Site traffic refers to the traffic generated by the proposed development. It is estimated by means of trip rates or trip regression equations, which relate estimated volume of generated trips to one or several independent parameters. The trip rates or trip equation vary with the type and size of the development as well as with different periods of a day and week. The estimated trips are in units of vehicle trips. Impacts and mitigating measures are based on the worst conditions at peak periods. The estimation of peak hour trips is, therefore, particularly important.
14
A3.3.2
The independent parameters are: the number of units of dwelling, commercial or public/institutional buildings for the proposed land use; total floor area; gross leasable floor area (GLFA); total development area (usually used for large development) and others (e.g. number of staff, number of residence, number of students, etc). The v�iues for these parameters should be extracted from the proposed· development plan.
A3.3.3
Trip rates are simple ratio of trips per unit of selected parameter (e.g. trips per unit of semi detached house), while trip equations are regression equations. which relates the two values. Such equations are derived from actual surveys carried out for trip generation analysis.
A3.3.4
Site Traffic is the estimate of the number of additional trips produced and attracted by the proposed development. Irrespective of the number of phases the development will be implemented, Site Traffic shall be estimated for the full completion of the development.
.
A3.3.5
The most current version of The Malaysian Trip Generation Manual (MTGM) published by the Highway Planning Unit of the Ministry of Works, Malaysia, shall be used as the main reference for trip generation rates.
A3.3.6
Equations provide more accurate estimates and must always be used if available.
A3.3.7
The vehicular trips need to be converted into passenger car equivalent (pcu) values before the subsequent steps of trip distributfon and trip assignment can proceed. The pcu/vehicle conversion factors for various types of vehicle are given in Table A3.3:7. For any conversion factor which is not available in the Table, the TIA assessor can select a suitable factor by making reference to other authoritative sources. Such reference sources must be declared in the TIA report.
15
Table A3.3.7: PCU Conversion Factors Equivalent Value in pcu ··
1
Type of Vehicle
Rural 1 Standard >
Urban Standard'>
Passenger Cars
1.00
1.00
1.00
Motor Cycles
1.00
0.75
0.75
Light Vans
2.00
2.00
2.00
1.00
Medium Lorries
2.50
2.50
2.80
1.19
Heavy Lorries
3.00
3.00
2.80
2.27
Buses
3.00
3.00
2.80
2.08
Reference: 1) 2)
Round-About ·\ Traffic Signal , . Design2) Design'> . '
.
1.00 0.22
''A Guide on Geometric Design ofRoads", Road Engineering Association of Malaysia, 2002 Highway Capacity Manual Malaysia, HPU, 2006
Trip Distribution A3.3.8
Each trip has two ends: an origin and a destination, or commonly called an 0-D pair. In the trip generation process, only the number of trip ends in the proposed development is estimated, i.e. the number of trips produced (out-going) by the development and the number of trips attracted (in-coming) to the development are calculated. Trip ends are connected to form trip interchanges or 0-D pairs. Trip distribution models are formulated to predict zone-to-zone trip interchanges.
A3.3.9
In a traffic model, the results of trip distribution process would take the form of a zone-to-zone trip matrix of 0-D pairs for the study area. It provides the number of trips originated from a particular traffic zone and how many of these trips are distributed to all other zones in the study area. Traffic modelling can take the form of a sophisticated computer model or a simple model using manual computation.
16
A3.3.10
In manual computation, the trip distribution stage would involve the estimation of how the trip ends so generated by the proposed development are to be distributed to the different siccess routes associated with the development. Both the out-going trips and the in-coming trips have to be considered, forming a two-way trip interchanges with these access routes. A corrtmon approach is to distribute these trip ends proportionally t9 the observed traffic volumes on these access routes. The basis of this approach rests on the assumption that the propensity or the likelihood for a trip to access the proposed development via a certain route is directly proportional to the traffic volume on that route. In other words, it is assumed that an access route with a higher traffic volume would tend to· channel more access traffic to the development than one with a low traffic volume.
A3.3.l 1
In performing trip distribution with computer, a common basis for converting zone-to-zone trip productions and trip attractions into trip interchanges is the Gravity Model. The Gravity Model rests on two principal assumptions: (a)
A trip produced in one zone is more I1kely to be attracted to another zone which has a higher number of trip attractions;
(b)
Similarly, a trip produced in one zone is also more likely to be attracted to another zone which is closer to it (which is analogous to Newton's law of gravity, hence the name Gravity Model).
for computer modelling, there are several proprietary software packages available in the market. TIA Assessor must obtain the agreement of the Approving Authority on the usage of any particular software. A3.3.12
Computer traffic modelling shall be employed for any proposed development that has a Gross Floor Area (GFA) of 1.8 million sq. ft. or generates a two-way traffic volume of 3,000 vehicle trips per hour or more. For a proposed development the GFA or generated traffic of which both fall below the respective threshold, however, manual computation can be accepted.
17
Trip Assignment A3.3.13
At this stage, the total volume of trips produced by and attracted to the proposed development, and their directions of flow would have been determined. The subsequent step is the assignment process whereby the generated trips are as$igned to the road network in the study area. This process . is: ,essential before assessment of impact on the road network in. the study area can be carried out. The aim of assigning the generated trips is to estimate the volume of traffic in the ImpaGt Analysis Year (IAY) at affected roads and junctions.
A3.3.14
Trip assignment models are formulated to predict the number of trips using various routes and, hence the traffic on the links and intersections of a road network. They help to determine, for a particular set of trip interchanges or 0-D pairs,-which set of links or roadways within the road network in the study area will be used to reach the desired destinations. The assumption for most assignment or route choice models is that people will choose the route which offers the shortest travel time (or, incurs the least cost of travel). In accordance to this principle, trip interchanges may then be assigned onto the set of routes dynamically or sequentially (as the preferred routes become increasingly congested, other routes may become attractive as alternatives.) For the use of computer software for trip assignment, clause 3.3.12 applies.
A3.3.15
For developments which are relatively small in scale, the volume of traffic distributed in accordance with section Trip Distribution above may be assigned directly onto roads in the study area to obtain the total traffic volume on the affected roads in IAY. (As these road links are, in general, located in the close vici7:ity of the proposed development, the assumption here is not about optimized travel times as route choices as in a typical traffic model, but more on the availability of access routes and th_eir relative popularity as an access choice.)
A3.3.16
For the purpose of traffic impact analysis, modal split between private and public transport shall not be considered. In other words, there shall be no reduction in the projected generated traffic due to the anticipated usage of public transport. However, this rule does not apply to integrated public transport hub development and transit oriented development (TOD). A TOD is a mixed-use residential or commercial development designed to maximize access to public transport. It must contain specific features to encourage transit ridership. It is usually developed at an existing transit station or simultaneously with the development of a new transit station which will become operational when the proposed TOD is completed. 18
A4. NETWORK CONDITIONS AND IMPACT ANALYSIS A4.1
Definitions of Terms Used Herein
S ubmission Year (S Y)
The calendar year in which the Deyeloper submits his Development Proposal Report to J�e Approving A uthority for Planning Permission. ·
Completion Year (CY)
The calendar year in whicp. the proposed development is fully completed and operational. If the project is divided into phases, CY refers to the year the final phase is completed and operational.
Impact A nalysis Year (IAY)
(a) If CY is less than 10 years from SY, then IAY shall be 10 years from SY; or (b) If CY is more than 10 years from SY, then the IAY shall be the same year as CY.
Designated Locations
(1) All points of connection between the development and the existing road network; and (2) Sections of existing road, junctions and locations of traffic conflict which are identified by the A pproving Authority in the existing network for traffic impact analysis. [In doing so, the approving Authority shall take into consideration: (a) the routes which will be used by the generated traffic to and from the project; and (b) the diminishing impact of the generated traffic as it spreads over the road network.]
Baseline Traffic ' Conditions in IAY
The traffic conditions (LOS) in the Impact Analysis Year at designated locations of the road network within the demarcated study area taking into consideration only the non-site traffic growth in the network from SY to JAY, excluding the effect of the generated traffic from the development.
Development Impacted Traffic Conditions in IAY
The traffic conditions (LOS) in IAY at designated locations of the road network within the demarcated study area, taking into consideration both the Non Site traffic growth from SY to IAY in the network as well as the Site-Traffic generated from the development in IAY.
Minimum traffic condition (LOS) after mitigation measures
The level of service as shown in the Table in Section 11 for each of the Designated Locations to be achieved at JAY with mitigation measures.
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A4.2 . Impact Analysis A4.2.1
The traffic impact caused by the proposed development is defined as the negative change in the LeveJ of Service (LOS) indicated by the comparison of the Baseline Tr�ffic Conditions in IAY against the Development Impacted Traffic Conditions in •. IAY.
A4.2.2
Unless otherwise agreed between the Traffic Impact Assessor and the Approving Authority, the computation of LOS shall be based on the recommendations of the latest version of the HIGHWAY CAPACITY MANUAL published by TRANSPORTATION· RESEARCH BOARD of The National Academies of USA, with appropriate modifications given in the latest version of the Highway Capacity Manual _(HCM) Malaysia published by the Highway Planning Unit, Ministry of Works, Malaysia.
A4.2.3
The traffic impact shall be examined at each and every one of the designated locations. These designated locations shall include: (1) all points of connection between the development and the road network, and (2) sections of existing or future roads, junctions and locations of traffic conflict in the study area that have been identified and agreed prior to the study by the Approving Authority and the TIA assessor.
A4.2.4
For each individual intersection, LOS of each lane group of all approaches shall be presented individually. Overall LOS of an intersection, though useful as an indicator of the overall performance of that intersection, is not relevant in the TIA study. Apart from the LOS, the respective degree of saturation (v/c ratios) as well as the maximum queue lengths shall also be computed and presented.
A4.2.5
LOS of junctions and mid-block shall be analysed individually. When a segment (the one-directional distance from one signalised intersection to the next) of a road is less than 300m, the adjacent junctions shall be analysed together, taking into account the mutual influence of the junctions and paying particular attention to queue lengths.
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Note:
•
Level of Service (LOS) provides an indication or measure of fhe operational condition of the facility concerned A range from ''A" to ''F" is applicable; LOS ''A" represents an excellent level of operational conclition, while LOS ''F" an undesirable, exceedingly congested and failed situatiOlJ..
•
Volume I capacity ration (vie ratio) or degree of saturation gives a measure of the level of utilisation of the facility. It indicates how much spare capacity or how saturated thefacility has become.
•
Queue length computation provides information on the length of storage lane required in junction design.· When designed appropriately, storage lane helps to avoid one trajjic movement from obstructing the other at an inte,:section.
•
Where dedicated storage lane for the vehicles queuing for turning is not available or inadequate, one possible mitigating measure is to re-compute the LOS with the turning vehicles sharing the lanes with the through traffic.
AS. MITIGATION MEASURE A5.1
Where the analysis shows that there will be negative impact, mitigation measures must be proposed to upgrade the road facilities at that location so as to achieve the requirements set out in Section 11 of these Guidelines. This proposal, the costs of design and construction of which shall be borne by the Developer, shall be included in the submission for Planning Permission.
A5.2
In developing mitigation measures, possible improvements in relation to site access, geometry, traffic signal timing, new facility, traffic management and other operational issues should be investigated.
AS .3
When reasonable improvements cannot sufficiently mitigate the resulting impacts from the development, a review of the proposed development in terms of project size, land use, development density or plot ratio shol.lld be carried out, with a view to lessen or reduce the level of such impacts to within the acceptable level.
A5.4
In the case where the IAY baseline traffic conditions (from the "without development" scenario) is already lower than LOS E, then it is an indication that the existing network cannot sustain additional traffic load from any new • development. In such a case, the TIA assessor should advise the developer to reconsider the proposed development until such time or situation when the existing transport network may be upgraded and the traffic conditions have improved to a level higher than the acceptable level. Otherwise, the Developer would have to undertake the upgrading works himself. 21
A5.5
A preliminary design drawing of the upgraded facilities shall be presented in A3 size paper. The design shall comply with the relevant standards published by the Road Engineering Association of Malaysia. •C
A5.6
The drawing shall show the boundaries of land �quired, indicating '· additional land to be acquired where necessary.
AS. 7
The TIA Assessor shall submit design calculations together with the drawing to demonstrate that the requirements of Section 11 of these Guidelines can be achieved by the mitigation. This includes a re-computation of the traffic condition of the Designated Locations after incorporating the proposed mitigation measures.
A6. TIA �PORT A6.1
The final TIA report shall contain at least the items listed below. The TIA Assessor shall have the liberty to modify or include further items where deemed necessary.
" Executive Summary ' - Brief description of proposed development - Summary of traffic impact analysis - Brief description of proposed mitigation measures and the extent they can mitigate the impact
Introduction - Description of proposed development - Traffic impact study methodology Defining the study area/boundary - Scope of study - Records of discussions and agreement with Developer and Approving Authority - Description of road network within the agreed area of study - Map of road network in area of study Determining existing traffic - Description of traffic generators in and around the study area - Identification of other developments with planning approval but not yet implemented - Identification of committed transportation projects in the study area. - Identification of designated links and intersections - Examination of historical data (including traffic accident) - Volume survey of current traffic flows in designated links and intersections within the study area - Survey of pedestrian flows at critical locations 22
Land use study - Description of current planning policies of the Approving Authority for the site of the proposed development including parking standards - Description of current usage of the site of proposed dev�lopment - Description of land use of the proposed development, including site �. area and development phasing - Breakdown of types and units ofbuilding in the propos·ed development - Site. and layout plans Trip Generation - Computation of trip generation (non-site traffic and site traffic) - Estimation of trip generation ·for peak hours (with weekday and development peak if necessary) - Justification of the values used - Computation of peak traffic volume, i.e. combination of Site and NonSite traffic - Specification of trip attraction by phase (if appropriate) - Justification for methodology adopted for trip distribution and assignment - Estimation of traffic growth rate over time for b0th Site and Non-Site traffic Impact Analysis - Description of capacity analysis technique - Details of traffic impact analysis result - List oflocations where mitigation oftraffic impact needs to be addressed Mitigation Measures - Description of proposed mitigation measures - Preliminary plans of mitigation measures - Details of computations and analysis showing that the mitigation criteria as given in Section 11 of these Guidelines have been met Conclusions
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ACKNOWLEDGEMENTS 'L
The following persons are members of the committee which produced tJlis document "Guidelines for Traffic Impact Assessment". Their contribution, singly and severally, are �· deeply appreciated. Datuk Ir. Md Amir bin Kasim
Chairman
Dato Ir. Chew Swee Hock
Deputy Chairman
Ir. Chin Kar Keong Ir. Dr. Tai Tuck Leong Prof. Dr Ahmad Parhan bin Mohd Sadullah Prof. Dr. Wan Hashim bin Wan Ibrahim Prof. Dr. Meor Othman bin Hamzah Prof. Madya Ir. Adnan bin Zulkiple
, '
Ir. Shamsuddin bin Sabri Ir. Alan Wong Dr. Madzlan bin Napiah Ir. Dr. Leong Siew Mun Dato Ir. George George Encik Goh Bock Yen Puan Jamariah binti Isam. Encik Husin bin Abdul Rahman Ir. Johari bin Embi Puan Noraini binti Roslan Puan Maizura binti Madzalan Dato r Ir. Han Joke Kwang Ir. Lee Ho Sing Ir. Aik Siaw Kong Ir. Tai Meu <;:'.hoi
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