PARKING REQUIREMENT GUIDELINES
UNITED ARAB EMIRATES
Department of Municipalities and Agriculture
Abu Dhabi Municipality
1. INTRODUCTION ...1
1.1. Background...1
1.2. Need for Traffic Impact Studies ...2
1.3. Need for Parking Requirements...2
1.4. Objectives of Traffic Impact Study and Parking Requirements ...3
1.5. How These Guidelines were Developed...3
1.6. References...4
2. APPLICATION OF REQUIREMENTS ...5
2.1. How Do Traffic Impact Studies and Parking Studies Fit Within the Development Review Process?...5
2.1.1. Land Development Review Process ...5
2.1.2. Incorporation of Traffic Impact Study and Parking Study Requirements into the Review Process...6
2.2. When is a Traffic Impact Study Needed? ...6
2.2.1. Criteria for Determining the Need for a Traffic Impact Study ...8
2.2.2. Procedures for Obtaining Exemptions from the Requirements for Traffic Impact Studies...8
2.3. When Do Parking Requirements Apply?...8
2.4. Qualifications of Study Preparer...8
2.5. Qualifications of Study Reviewer...9
3. SCOPE OF TRAFFIC IMPACT STUDY ...10
3.1. Summary of Traffic Impact Study Process...10
3.2. Initial Meeting and Development of Inception Plan...11
3.2.1. Notification ...13
3.2.2. Initial Meeting...13
3.2.3. Inception plan for Traffic Impact Study ...13
3.3. Study Area ...14
3.4. Key Facilities to be Analyzed...14
3.5. Horizon Year(s) ...15
3.6. Peak Hours of Analysis...15
3.7. Methodologies and Procedures...16
3.7.1. Level of Service Calculation Methodologies...16
3.8. Impact Analysis and Mitigation Strategies ...18
3.9. References...18
4. ANALYSIS OF EXISTING CONDITIONS...19
4.1. Development Site Location...19
4.2. Description of Current Land Uses on Development Site...19
4.3. Description of Surrounding Transportation System ...21
4.3.1. Study Area ...21
4.3.2. Existing Roadway System ...21
4.3.3. Existing Public Transport and Taxi Service ...23
4.5. Reporting Existing Levels of Service on Key Facilities...26
4.6. References...29
5. ESTABLISHING FUTURE YEAR BASELINE CONDITIONS...30
5.1. Methods and Data Considerations ...30
5.2. Assumptions Regarding Future Year Land Use and Population ...30
5.2.1. Regional Growth Assumptions...31
5.2.2. Related Developments in the Study Area ...31
5.3. Assumptions Regarding Future Transportation Improvements...32
5.3.1. Highway and TSM Improvements...32
5.3.2. Public Transportation Service and TDM ...33
5.4. Determining Future Year Baseline Traffic Volumes...33
5.4.1. Manual Method for Determining Future Year Baseline Traffic Volumes 33 5.4.2. Model Method for Determining Future Year Baseline Traffic Volumes 34 5.5. Evaluation of Baseline Traffic Conditions ...35
5.6. References...35
6. TRIP GENERATION ...36
6.1. Development Description ...36
6.2. Development Trip Generation ...37
6.2.1. Peak Hours ...37
6.2.2. Trip Generation Rates ...38
6.2.3. Primary vs. Linked Trips ...38
6.2.4. Internal Capture ...39
6.2.5. Mode Split Variations ...40
6.2.6. Tables of Existing and Future Development Trip Generation...40
6.2.7. Information On Available Trip Generation Resources...40
6.3. Choice of Trip Rates ...41
6.4. References...41
7. SITE TRAFFIC DISTRIBUTION AND ASSIGNMENT ...42
7.1. Trip Distribution ...42
7.1.1. Manual Methods ...43
7.1.2. Model-Based Methods...45
7.2. Trip Assignment...46
7.3. References...46
8. ANALYSIS OF DEVELOPMENT-RELATED TRANSPORTATION IMPACTS ...48
8.1. Quantifying Development-Related Transportation Impacts...48
8.1.1. Traffic Impacts...48
8.1.2. Other Transportation Impacts ...49
8.2. Thresholds for Determining Significant Transportation Impacts ...50
8.2.1. Approaches to Defining Significance Thresholds ...50
8.2.2. Significance Thresholds for Abu Dhabi ...51
8.3. References...52
9. DEVELOPMENT OF MITIGATION PLAN ...53
9.1.1. Objectives of Mitigation Plan ...53
9.1.2. Quantifying the Benefits of Mitigation Measures ...53
9.2. Potential Mitigation Strategies...56
9.2.1. Intersection Improvements...56
9.2.2. New Roadways, Extensions, Roadway Widening, and Interchanges..57
9.2.3. Operational or Transportation System Management Improvements ...57
9.2.4. Transportation Demand Management...57
9.2.5. Modifications to Definition of Development and/or Site Plan ...58
9.3. Implementation and Phasing of Mitigation Measures ...58
9.4. Review and Approval of Proposed Mitigation Plan ...58
9.5. References...59
10. MULTIMODAL SITE ACCESS, CIRCULATION, AND PARKING DESIGN 60 10.1. Importance and Scope of Site Access and Circulation ...60
10.2. Site Plan ...61
10.3. Site Access, Circulation, and Parking Design ...62
10.3.1. Site Access...62
10.3.2. Access Design...62
10.3.3. Internal Roadways ...63
10.3.4. Delivery, Service and Emergency Vehicles...64
10.3.5. Taxi and Public and Private Transport Vehicle Access...64
10.3.6. Pedestrian and Bicycle Access and Circulation...64
10.3.7. Parking Design and Layout...65
10.4. References...66
11. PARKING REQUIREMENTS...67
11.1. Overview...67
11.2. Parking Rates in Abu Dhabi ...67
11.2.1. Parking Rates in CBD and High-Density Sectors...67
11.2.2. Publicly Available Parking Supply vs. Reserved Parking Supply in the CBD and High-Density Areas ...69
11.2.3. Parking Rates for All Other Developments ...70
11.3. Parking Analysis Requirements...71
11.3.1. Simple Parking Analysis (Proposed Development Meets Parking Requirements Directly)...71
11.3.2. Complex Parking Analysis (Proposed Development Does Not Meet Parking Requirements Directly) ...72
11.4. References...74
12. FORMAT OF TRAFFIC Impact Study and PARKING REQUIREMENT STUDY Report ...75
12.1. General Characteristics ...75
12.2. Structure of Report...75
Figure 2-1...7
Abu Dhabi Traffic Impact Study and Parking StudyRequirements...7
Figure 3-1...12
Abu Dhabi Traffic Impact Study Process ...12
Figure 3-2...17
Level Of Service Definitions For Signalized And Unsignalized Intersections ...17
Figure 3-3...17
Figure 6-1:...39
Trip Types (Source: Institute of Transportation Engineers, Trip Generation Handbook, 2001)...39
Figure 7-1...45
Example Application of Area-of-Influence Method (Source: V. Stover and F. Koepke, Transportation and Land Development, 2002) ...45
Figure 11-1...68
Abu Dhabi CBD and High-Density Areas...68
Table 5-1 Summary Of Future Year Baseline Traffic Conditions...35
Table 8-1 ...49
Quantification of Development Related Traffic Impacts in Study Area ...49
Table 8-2 ...52
Significant Thresholds for Development-Related Transportation Impacts ...52
Table 9-1 ...55
Quantification Of Mitigation Measure Benefits ...55
Table 11-1 ...71
1.
INTRODUCTION
This document is intended to provide public agencies, private landowners, their consultants, and Municipality staff with standards, guidelines, objectives and criteria to be used in the preparation of traffic impact and parking studies for developments. Such studies may be required for proposed developments prior to the issuance of Building Licenses. In order to ensure timely review by the Municipality Roads Directorate, the policies and procedures provided herein are to be followed in the preparation of Traffic Impact and Parking Study reports. This introductory chapter provides background regarding Abu Dhabi’s recent development, and explains the need and main objectives of establishing traffic impacts study and parking requirements.
Abu Dhabi Municipality’s Roads Directorate has published these policies and procedures to ensure that appropriate mitigation measures will be identified and implemented for those developments that cause traffic impacts, while not unnecessarily burdening smaller projects or those in less congested areas.
1.1. Background
Abu Dhabi is the capital of the United Arab Emirates (U.A.E.), a country established in 1971 as a federation of seven Trucial States: Abu Dhabi; Dubai; Ras Al Khaimah; Fujairah; Umm Al Quwain; and Ajman. The booming economy of Abu Dhabi has led to a large increase in population, rising ownership of cars and trucks, and substantial growth in traffic. The population in the Abu Dhabi Emirate has grown from 200,000 in 1975 to over 900,000 in 2000. Greater Abu Dhabi, including Abu Dhabi Island and neighboring island and mainland developments, has a year 2000 total population estimated at 575,000.
Abu Dhabi Municipality has implemented major infrastructure projects to cope with the region’s growth. As a result, the city today has a modern transportation system. The road network is laid out in a rectilinear pattern, and the wide arterial streets typically have dual 3-lane carriageways.
Abu Dhabi continues to grow rapidly. Although much of the new growth is in the communities on the mainland, such as Shahama and Shamka, a substantial amount of growth still occurs in Abu Dhabi Island, including the Central Business District (CBD). The CBD is characterized by high-density mixed land uses. Much of the growth in the CBD is in the form of redevelopment of existing buildings to greater intensity.
This rapid growth places heavy demands on the transportation system, both in terms of roadway capacity and parking supply. Recognizing the future needs being created by this tremendous growth over the next two decades, the Municipality has proposed a series of strategies and actions to ensure that the city continues to enjoy adequate system performance in the coming years.
1.2. Need for Traffic Impact Studies
While the Municipality is actively designing and implementing transportation improvements aimed at maintaining and enhancing transportation system performance, it is not possible for the Municipality to anticipate incremental impacts that may occur with the addition of each individual development.
In order to ensure that operational problems do not arise at the local level, the MTP proposed that Traffic Impact Study Guidelines be developed as quickly as possible, and that regulations be adopted that require new developments to conduct traffic impact studies prior to obtaining development approval. The MTP further recommended that parking requirements be included in these guidelines. Such guidelines are necessary to ensure a consistent process is followed for all proposed developments. They serve as an important tool for the management of urban growth, and greatly reduce the possibility that additional demand on the transportation network due to new developments results in local problems regarding traffic operations, traffic safety, or other problems.
Traffic impact study guidelines include procedures for estimating project traffic impacts on the surrounding transportation network, and for identifying mitigating measures that maintain a satisfactory level of service. Just as important, site access and circulation by automobiles, public transportation, pedestrians, and bicycles, are assessed and improvements recommended. Access requirements for the elderly and physically disadvantaged are also addressed
It should be stressed that effective implementation of these guidelines is of benefit to the city as well as the developer asked to prepare the study. Adequate transportation network performance in the area surrounding the planned development benefits those accessing the project as well as the community at large.
Moreover, even large and expensive developments often suffer from design oversights in regard to site access and on-site circulation that could lead to serious operational problems if left unsolved. These problems may be difficult and expensive to solve after construction of the development is complete. The Traffic Impact and Parking Requirements will help to identify such problems and develop appropriate solutions.
1.3. Need for Parking Requirements
Many cities have learned that the problem of increasing parking shortages can be reduced or eliminated if all new developments are required to meet their own parking needs. It is the objective of these policies and procedures to end the growth in parking shortfalls in the CBD and to ensure that similar parking shortfalls do not occur in other areas of the city. Parking requirements ensure that on-site parking demand is assessed and that adequate parking is provided on-site to ensure that parking problems in the area are not created or exacerbated.
Provision of parking by new developments, combined with the ongoing parking structure program of the Municipality and the comprehensive parking management
plan that is being developed, will eventually lead to a balance between supply and demand for parking in the city.
1.4. Objectives of Traffic Impact Study and Parking
Requirements
Land development in urban areas often impacts the performance of the transportation system. Conducting traffic impact studies and establishing parking requirements is a prerequisite to orderly land development. The overall goal of traffic impact studies and parking requirements is to ensure that any negative impacts of the new development on the transportation system are identified and mitigated. Specific objectives serving this goal include the following:
• To assess traffic impacts on the transportation network surrounding a proposed new development;
• To assess site access and site circulation and propose measures to overcome any problems that are identified; and
• To assess the parking demand of the new development and determine the manner in which that parking demand be met.
The development of guidelines for how to conduct traffic impact studies and determine parking requirements has the following aims:
• To provide decision makers with a basis for assessing the transportation implications of approving proposed development applications;
• To assist developers through the approval process by outlining the requirements and level of detail of traffic analysis that will be required of them during the approval process;
• To standardize the types of analysis required in the assessment of traffic impacts and parking requirements for developments and thereby ensure consistency in the preparation and review of traffic impact studies; and
• To provide a basis for estimating the cost of proposed mitigation measures.
1.5. How These Guidelines were Developed
Due to its comprehensiveness, the ITE's "Traffic Access and Impact Studies for
Site Development, A Recommended Practice” served as a basic reference for this
study. Traffic impact study guidelines and parking requirements prepared for cities in the US, the UK, Dubai, and other locations were also consulted. These guidelines were prepared by reviewing these sources and developing the most appropriate approach for the conditions in Abu Dhabi. A list of all the documents consulted in the preparation of these guidelines is provided in Appendix A. Documents consulted for specific chapters are listed at the end of each chapter.
1.6. References
1. Institute of Transportation Engineers, Traffic Access and Impact Studies for
Site Development, 1991.
2.
APPLICATION OF REQUIREMENTS
Traffic impacts study and parking requirements are only one element of the land development review process. This chapter summarizes the manner in which planned developments are reviewed before approval for construction, and explains how the review process can include the traffic impact study and parking requirements. Criteria are also defined that specify under which conditions a traffic impact/parking requirements study is required.. The chapter concludes with a discussion of the qualifications required of the transportation professionals who prepare or review these studies.
2.1. How Do Traffic Impact Studies and Parking Studies Fit
Within the Development Review Process?
In this section, an outline of the land development review process in Abu Dhabi is followed by a description of how the traffic impact study and parking requirements are to be inserted into that process.
2.1.1. Land Development Review Process
Before a development can proceed into construction, the development must successfully pass through the land development review process. This process includes review by the Municipality’s Town Planning, Engineering, and Sewerage Sections, as well as the Civil Defense Department. With the publication and application of these guidelines, this review process will also include a review by the Roads Directorate. This section summarizes the main features of the land development review process.
Once a parcel of land has been granted to a private individual or a public agency, and the land use specified, the land development review process of the Abu Dhabi Municipality and Town Planning Department ensures that the actual development of the land meets Municipality requirements. The landowner or the consultant hired to design the facility may notify the Town Planning Department of its plans and proceed with obtaining the necessary approvals. The Abu Dhabi Municipality and Town Planning have issued a detailed description of all the various regulations and ordinances in the form of a booklet named ‘Code Governing Construction Activities and Executive Ordinance’.
The Town Planning Department reviews the site plan, architectural drawings, and proposed land use, and ensures that regulations and guidelines related to architectural standards and building style, as well as building heights/number of floors, setbacks, and others, are observed. Following successful completion of this review, a Building Permit is issued. Despite its name, a Building Permit does not mean that a facility has been approved for development and construction quite yet.
The review process then shifts to the Engineering Section, who reviews the engineering drawings for structural adequacy, and issues a permit as appropriate.
This process has recently been streamlined for greater efficiency, and is centrally administered in a separate building next to the ground floor of the Town Planning building. Even the Civil Defense permit can be obtained from within Municipality premises.
When all necessary permits have been obtained, the Municipality issues a Building License, which allows the owner to develop the land.
2.1.2. Incorporation of Traffic Impact Study and Parking Study Requirements into the Review Process
With the publication of these guidelines, the land development and review process now includes a review by the Roads Directorate of the Municipality and Town Planning Department. (While the Roads Directorate does not issue a “permit” as such, it does provide a letter signed by the Director of Roads Directorate which indicates that the Traffic Impact and Parking Requirements Study report has been reviewed and approved, or indicates that an exemption has been given enabling the development to proceed without the report). This letter carries the same level of significance as the development review permits described above. It is necessary to obtain the approval letter from the Director of Roads Directorate prior to obtaining the Building License.
Depending upon their size and characteristics, proposed developments may be required to have a traffic impact study, a parking study, both, or none. If a proposed development is required to have both a traffic impact study and a parking study, the two study reports may be submitted separately, or submitted in a single joint traffic impact and parking study report.
2.2. When is a Traffic Impact Study Needed?
A Traffic Impact Study is generally needed whenever a proposed development is likely to generate sufficient levels of additional traffic to cause an impact on the surrounding transportation system. The Director of Roads Directorate determines whether a Traffic Impact Study will be needed for any individual development proposal. This section provides criteria that will be used, in most cases, to determine the necessity for a Traffic Impact Study. It is possible, however, that other factors may contribute to the determination in some cases.
Figure 2-1
Abu Dhabi Traffic Impact Study and Parking StudyRequirements
NOTIFICATION TO ROADS DIRECTORATE OF PROPOSED DEVELOPMENT ROADS DIRECTORATE REVIEW OF PROPOSED DEVELOPMENT ANALYZE TRAFFIC IMPACTS AND PREPARE MITIGATION PLAN ANALYZE PARKING REQUIREMENTS SUBMIT PARKING STUDY REPORT – DRAFT AND FINAL SUBMIT OPTIONAL JOINT TRAFFIC IMPACT AND PARKING STUDY REPORT – DRAFT AND FINAL SUBMIT TRAFFIC IMPACT STUDY REPORT – DRAFT AND FINAL Traffic Impact Study Needed? Yes No Parking Study Needed? No Yes NO FURTHER ACTION REQUIRED NO FURTHER ACTION REQUIRED
2.2.1. Criteria for Determining the Need for a Traffic Impact Study
Traffic Impact Studies will generally be required when a proposed development meets or exceeds one or more of the following criteria.
1. A residential development that has 30 or more housing units or provides housing for 150 or more workers.
2. Any other development that is expected to generate 100 or more vehicle trip ends (sum of departures and arrivals) during the AM or PM peak hour. Estimates of peak-hour development vehicle trip generation must be consistent with the parameters and procedures in Chapter 6 of these guidelines.
2.2.2. Procedures for Obtaining Exemptions from the Requirements for Traffic Impact Studies
Exemptions from the requirements to provide Traffic Impact Studies may be requested in writing addressed to the Director of Roads. Such requests must include a description of the proposed development and the factors to be considered in considering the request. The Roads Directorate will notify the applicant of its decision in writing within 30 days of receiving the request, indicating whether the request is granted or rejected. The Roads Directorate may request additional information from the applicant while considering the request.
2.3. When Do Parking Requirements Apply?
While a traffic impact study is not required of all developments, all proposed developments must demonstrate provision of sufficient parking spaces to meet the parking needs. Chapter 11 of these guidelines details the manner in which parking demand for a development is estimated, and how parking should be provided by the developer.
For small developments in certain locations (such as a villa in a particular mainland community), demonstration of adequate parking may be straightforward by submitting the site plan. In sectors with excess parking supply, credits may be granted for nearby excess parking spaces, at the discretion of the Roads Directorate. In sectors with parking shortages, the Municipality may be in the process of building additional parking spaces and it may be possible for the proposed development to benefit from these additional spaces. Financial contributions toward Municipality-supplied parking may be required. The Roads Directorate is developing a comprehensive parking management plan, which may result in additional mechanisms to ensure new developments do not contribute to a worsening of the parking situation.
2.4. Qualifications of Study Preparer
Traffic Impact Studies should be prepared under the supervision of a qualified and experienced transportation engineering/transportation planning professional who has training in traffic and transportation engineering and several years of experience in
preparing traffic impact studies for existing or proposed developments. A Masters degree in transportation or traffic engineering and 10 or more years of experience is desirable. Approval of the individual responsible for the Traffic Impact Study is at the discretion of the Roads Directorate. The qualifications of the individual responsible for the Traffic Impact Study are to be presented to the Roads Directorate concurrently with the proposed scope of work (see Chapter 3 of these guidelines).
2.5. Qualifications of Study Reviewer
Review of Traffic Impact and Parking Requirements Study reports is to be performed by one or more Roads Directorate staff who collectively have training and experience in traffic impact study methodology, land use planning and traffic engineering, including traffic safety and operations. The Head of the Roads Directorate will determine if individuals within the Roads Directorate have these qualifications to review the reports.
3.
SCOPE OF TRAFFIC IMPACT STUDY
The primary purpose of a traffic impact study is to identify impacts of the proposed development on the surrounding transportation network, and to determine appropriate measures to mitigate these impacts. The severity of the traffic impacts depends on the size and characteristics of the proposed development as well as the design and operational characteristics of the surrounding transportation network. For example, if a large shopping mall were planned in a congested downtown area, traffic flow might slow down considerably as a result of the additional traffic generated by the mall, and numerous intersections could be impacted. By comparison, a small planned development in the same area might impact only immediately adjacent roadways and intersections.
If the same mall were to be located on the mainland adjacent to a wide and uncongested freeway, however, the nature of the impacts on the adjacent roads might differ significantly. The freeway adjacent to the mall on the mainland might have sufficient unused capacity to handle the increase in traffic, and only immediately nearby interchanges might be impacted measurably.
The differences in impacts due to type and size of development and location also result in different approaches to mitigation strategies. In the case of the shopping mall in the congested downtown, significant physical and operational improvements might be required to overcome the decline in level of service. On the other hand, the decline in level of service due to the mall located on the mainland might be too small to necessitate identification and implementation of any mitigation measures.
Because of these differences between individual developments, and between the nature of the neighborhood and transportation network within which the developments are located, it is not practical to define a single scope of work that is applicable in every case. This chapter provides procedures to be used in determining the work scope to be applied on a case-by-case basis, and serves as a starting point for consultants who develop a inception plan. The Roads Directorate will review that plan and determine whether additional factors warrant modifications to that plan before approving the precise work scope.
Following a summary of the traffic impact study process, this chapter describes how the inception plan is developed, followed by a discussion of how to determine the study area, the key facilities to be analyzed, the horizon years, and the peak hours. The methodologies to be used for assessing the level of service of the facilities to be analyzed in the study area is then provided, followed by a pointer to impact analysis and mitigation strategies discussed in later chapters of this report.
3.1. Summary of Traffic Impact Study Process
The overall traffic impact study process is shown in Figure 3-1. This process generally consists of the following steps:
1. Introduction – A brief description of the proposed development, issues discussed in the initial meeting, definition of the study area, and overall approach to the traffic impact study.
2. Analysis of existing conditions – Summary of current conditions on the major arterial streets and internal roads surrounding the proposed development.
3. Establishing future year baseline (without-development) conditions – Summary of future year conditions without the development, based on assumptions regarding growth and planned transportation improvements in Abu Dhabi approved by Town Planning and the Roads Directorate respectively.
4. Development description and trip generation – Description of development in sufficient detail to estimate trip generation.
5. Development trip distribution and assignment – Estimates of changes in traffic on the surrounding major arterial streets and internal roads due to the proposed development.
6. Impact analysis – Determination of traffic impacts due to the proposed development.
7. Mitigation plan – Summary of proposed measures to mitigate development traffic impacts.
8. Multi-modal site/sector access and circulation analysis – Evaluation of access and circulation on-site and within the sector for highway vehicles, public transportation pedestrians and bicycles, and the design of development parking.
9. Parking Requirement – Assessment of the demand for parking generated by the development, and the manner in which this demand is met.
With the exception of the introduction, a separate chapter of this report provides guidelines for each of the above elements.
3.2. Initial Meeting and Development of Inception Plan
The first step in the traffic impact study process is to notify the Roads Directorate of intent to perform a study, and to develop a inception plan documenting what is to be done and how it is to be performed. It is strongly recommended that the applicant (landowner, developer, or consultant) notify the Roads Directorate of its intent to perform a traffic impact study, and to meet with the Roads Directorate in order to determine the precise work scope to be followed.
would be conducting the study without an assurance that the Roads Directorate has reviewed and approved the work scope for the study.
Figure 3-1
3.2.1. Notification
Notification of intent to conduct a traffic impact study is to be made in writing to the Director of Roads, P.O. Box 263, Abu Dhabi, United Arab Emirates. The notification should include preliminary information about the proposed development, including location, size, and land use(s).
3.2.2. Initial Meeting
Depending upon the size and complexity of the proposed development and/or traffic impact study, the initial meeting may be a simple brief meeting or may grow to a series of meetings with many attendees. Issues to be addressed in the initial meeting include:
• Details on Development type and size
• How much information is needed for a “complete” study? • What study area should be evaluated?
• What should be the horizon year(s)? • What peak hour(s) should be analyzed? • What technical analyses are required?
• What technical procedures and parameters should be utilized? • What special requirements, if any, should apply to the traffic impact
study for the proposed development?
• Who, within the Roads Directorate, will be assigned to coordinate with the applicant and review submitted products?
• What is the schedule for product submittal and review?
• What are the costs, if any, incurred by the Roads Directorate and to be reimbursed by the applicant?
• Other related issues
3.2.3. Inception plan for Traffic Impact Study
Either at the initial meeting or subsequent to the meeting, the applicant will submit a inception plan. The inception plan is the proposed work scope for the traffic impact study. It documents the approach agreed upon by the Roads Directorate and the applicant.
The inception plan for the traffic impact study should include but is not limited to the following:
1. A general description of the development including:
• Preliminary site plan, including locations of driveways and parking areas;
• Size (number of square meters by use and/or number of residential units by type); and
If the proposed development is to be constructed in phases, then a description of each phase of the development is to be included, together with the anticipated opening date of each phase.
2. A description of the study area, including:
• Intersections and roadway links to be studied; and • The area within the sector(s) to be analyzed.
3. A list of related developments planned within the study area.
4. An overall work scope, identifying those elements of the traffic impact study process to be included in the study.
5. A description of the methodologies and parameters to be used in performing the technical analyses.
6. Land-Use/Transportation assumptions to be used. 7. Names and qualifications of preparers.
3.3. Study Area
The size of the study area depends upon the location and size of the proposed development and the conditions prevailing in the surrounding area. The impact of large developments proposed in congested or poorly accessible areas may extend several intersections away from the development site. On the other hand, small developments may only require a study area that includes access driveways and immediately adjacent intersections. Thus the definition of the study area should only be as large as necessary to capture all significantly influenced facilities, in order to avoid unnecessary effort being spent analyzing and reviewing the study.
Since the area impact by the development is so closely related to both the nature of the development and the current and expected conditions in the surrounding neighborhood, there are no straightforward rules for defining the study area for a traffic impact study. At the minimum, the study area should include all development access points, adjacent intersections in the sector, and adjacent sector driveways, for development located in sectors. For developments elsewhere, the study area should include all development access points, plus major adjacent intersections (signalized and unsignalized). The Roads Directorate will determine the additional facilities to be included in the study area for each traffic impact study based on the specific characteristics of the proposed development, and the traffic conditions and transportation system characteristics of the surrounding area, as well as other concerns, factors, and policies. The inclusion of already congested facilities likely to be impacted by the proposed development will be an important criterion defining the study area.
3.4. Key Facilities to be Analyzed
The key facilities to be analyzed in traffic impact studies are determined by the Roads Directorate. In most cases, key facilities will include:
• All signalized intersections within the study area;
• All roundabouts connecting streets classified as collectors or higher within the study area;
• All all-way-stop-controlled intersections of streets classified as collectors or higher;
• All ramps connecting streets classified as arterials or higher within the study area;
• All freeways and expressways in the study area; • All local circulator roads within the study area; and • All sector/arterial driveways within the study area.
3.5. Horizon Year(s)
The horizon year will generally be the year that the proposed development is expected to be fully operational. For phased developments, separate horizon years representing the anticipated completion date of each phase may be required. For very large developments, in which the anticipated completion year is uncertain, a fifteen or twenty-year time horizon may be required.
The Roads Directorate will determine the horizon year(s) for the study. The Abu Dhabi Travel Demand Forecasting Model forecasts for the years 2005, 2010, 2015, and 2020. Future updates to the model will extend the horizon years modeled. When modeling is used in the analysis, as described in section 3.7, the Roads Directorate may elect to define a horizon year as the nearest year modeled after development buildout.
3.6. Peak Hours of Analysis
The peak hours to be analyzed will be determined during the initial meeting and documented in the Inception plan. Typically two peak hours of analysis will be required. The hours selected for the analysis will be based on peak hour trip generation estimates for the proposed development and the peaking patterns of traffic on the roadway system within the study area.
With the possible exception of some retail developments, the morning peak hour (7:00-8:00 AM) will most likely be required for all traffic impact studies. Depending upon the type of development, the second peak hour may be the noon (11:00 AM-noon), afternoon (2:00-3:00 PM), or evening (7:00-8:00 PM) peak hour. For example, if the proposed development is located in a downtown sector, the noon or evening peak hour may be selected. If the development is not in a downtown sector, the afternoon peak hour may be selected. If the proposed development is a school, the afternoon peak hour may be selected regardless of the school’s location. Exceptions to the choice of peak hour may be made in response to specific local or global conditions.
3.7. Methodologies and Procedures
Methodologies and procedures to be used in performing the traffic impact studies will be agreed to during the initial meeting and documented in the Inception plan. Some general rules for the choice and use of methodologies for level-of-service calculation of signalized and unsignalized intersections, roundabouts, and road segments are discussed in this section.
Manual and model-based methods of forecasting travel for future scenarios both with and without the proposed development are discussed in Chapters 6-7 of this report
3.7.1. Level of Service Calculation Methodologies
Level of service analysis must be conducted in conformance to these guidelines. Alternative methodologies may be proposed by the applicant and, following review by the Roads Directorate, may be accepted.
Signalized and Unsignalized Intersections
Levels of Service for signalized and unsignalized intersections shall be based on average control delay following methodologies and procedures outlined in the most recent edition of the Highway Capacity Manual (HCM) published by the Transportation Research Board (1). Figure 3-2 defines the levels of service for signalized and unsignalized intersections. Commonly used software packages utilizing HCM methodologies and procedures such as HCS and SYNCHRO (using the HCM Signals Report to determine delay) are acceptable for determining levels of service on signalized and unsignalized intersections. Use of other methodologies and procedures will be accepted only after Roads Directorate review and approval of the proposed methodologies and procedures. In reviewing other methodologies, the Roads Directorate will assess whether the proposed methodology provides results that are comparable to the results obtained using HCM-based methodologies.
For both signalized and unsignalized intersections, it is not only the average intersection control delay that determines the level of service of the intersection. Approach LOS and movement LOS are also important. If any approach or movement at an intersection is LOS F, then the intersection is considered to be LOS F. As long as all approaches and movements of the intersection are at LOS E or better, then the average intersection control delay will be the basis for determining the LOS.
Roundabouts
Levels of service for roundabouts shall be based on average queuing delay following methodologies and procedures developed by the Transport Research Laboratory (TRL) and documented in the ARCADY 5 (International) User Guide (3) or later version for right-hand-side driving. Figure 3-3 defines the levels of service for roundabouts. Use of ARCADY or other software based on the TRL methodologies and procedures are acceptable for determining levels of service on roundabouts. Use of other methodologies and procedures will be accepted only after Roads Directorate review and approval of the proposed methodologies and procedures. In reviewing other methodologies, the Municipality will assess whether the proposed methodology
provides results that are comparable to the results obtained using TRL-based methodologies.
Figure 3-2
Level Of Service Definitions For Signalized And Unsignalized Intersections
SIGNALIZED INTERSECTIONS LOS Average Control Delay
in seconds (1) Description of Traffic Conditions (2)
A 0 – 10.0 Excellent. No vehicle waits longer than one red light and no approach phase is fully used. B 10.1 – 20.0 Very Good. An occasional approach phase is fully utilized; many drivers begin to feel somewhat restricted within groups of vehicles. C 20.1 – 35.0 Good. Occasionally, drivers may have to wait through more than one red light; backups may develop behind turning vehicles. D 35.1 – 55.0 Fair. Delays may be substantial during portions of the rush hour, but enough lower volume periods occur to permit cleaning of developing
lines, preventing excessive backups.
E 55.1 – 80.0 Poor. Represents the most vehicles that intersection approaches can accommodate; may be long lines of waiting vehicles through several signal cycles.
F 80.1 and above
Failure. Backups from nearby intersections or on cross streets may restrict or prevent movement of vehicles out of the intersection approaches. Tremendous delays with continuously increasing queue lengths.
Figure 3-3
UNSIGNALIZED INTERSECTIONS LOS Average Control Delay
(Sec)1 Description of Traffic Conditions A 0 – 10.0 Excellent.
B 10.1 – 15.0 Very Good. C 15.1 – 25.0 Good. D 25.1 – 35.0 Fair. E 35.1 – 50.0 Poor. F 50.1 and above Failure.
For roundabouts, it is not only the average intersection queuing delay that determines the level of service of the intersection. Approach LOS is also important. If any approach leg at a roundabout is LOS F, then the roundabout is considered to be LOS F. As long as all approach legs of the roundabout are at LOS E or better, then the average roundabout queuing delay will be the basis for determining the LOS.
Links
Levels of service for segments of roadways and ramps shall be based on volume-to-capacity ratio (V/C). V/C is determined by comparing the observed hourly traffic volume to the capacity of the link. Link capacities are assumed as follows (4):
• Expressways and freeways, 2,000 vehicles per hour per lane; • Arterial streets, 780 vehicles per hour per lane;
• Arterial streets in the CBD, 580 vehicles per hour per lane; • Local roads, 580 vehicles per hour per lane; and
• Ramps, 1,500 vehicles per hour per lane. Other Operational Analyses
The Roads Directorate may request additional analyses, such as weave analyses or merge/diverge analyses, based on its review of a specific proposed development and its potential impacts. Such analyses must conform to the methodologies and procedures outlined in the latest edition of the Highway Capacity Manual.
3.8. Impact Analysis and Mitigation Strategies
The criteria and methods the consultant should use for defining and computing development impacts are discussed in Chapter 8. The chapter also discusses methods to determine whether these impacts are serious enough to warrant development of mitigation strategies. Chapter 9 discusses the manner in which mitigation strategies are to be developed. The manner in which on-site access and circulation are evaluated and improvements proposed is discussed in Chapter 10.
3.9. References
1. Los Angeles County Metropolitan Transportation Authority, 1997 Congestion
Management Program for Los Angeles County, November 1997.
2. Transportation Research Board, Highway Capacity Manual, 2000.
3. Transportation Research Laboratory, ARCADY 5 (International) User Guide, 2000.
4. Abu Dhabi Municipality and Town Planning Department, Abu Dhabi Master
4.
ANALYSIS OF EXISTING CONDITIONS
At the outset of a study it is necessary to characterize the existing conditions in and around the site under investigation, as well as to describe the area to be affected by the development. The characterization should represent current conditions and should generally be no more than one year old. These baseline data will provide a foundation for assessing the land use and transportation implication of changes over time.
This chapter establishes requirements for the data to be collected and used in the study, as well as specifying the requirements for the existing conditions analysis. It specifies the required information to be included in the “Analysis of Existing Conditions” chapter of the traffic impact study report.
4.1. Development Site Location
A map showing the study site in relation to the surrounding roadway must be provided in the traffic report. The map must be legible, and the size of the site and the amount of frontage available on all adjacent streets must be noted on it or in the accompanying text. Figure 4-1 is a sample of a site location map.
4.2. Description of Current Land Uses on Development Site
Current land uses on the development site are to be described. Current land use is defined as the most intense use during the six-month period prior to approval of the preliminary plan. If the site currently contains structures or other uses, these are to be described in sufficient detail to allow for trip generation estimation.
The description of current land uses on the development site includes:
• Number of dwelling units by type (villas, apartments, etc.);
• Number of hotel rooms;
• Number of group quarter units (labor camp rooms, student housing rooms, etc.);
• Intensity of non-residential use quantified in square meters (gross floor area) and classified as retail, school, office, industrial, social-recreational, or medical; and
• Other uses not identified above, quantified in square meters of gross floor area (where applicable) and/or estimated peak hour trip generation (for the peak hours to be analyzed in the traffic impact study as discussed in Chapter 6) if available.
Footprints of existing structures and other uses are to be shown on a map. Figure 4-2 is an example of a Current Site Land Use map. Where reasonable, footprints of current uses can be included in the Site Location Map.
4.3. Description of Surrounding Transportation System
The traffic study shall include a description of the study area and the existing transportation system serving the site including any specific operational issues. The following will be addressed in this section:
• Study area;
• Existing roadway system and parking facilities;
• Existing public transportation and taxi service; and
• Existing pedestrian facilities.
4.3.1. Study Area
This section will describe the boundaries of the study area and give a general description of the land uses therein. Typically, the study area boundaries will be determined in the initial meeting and documented in the Preliminary Plan. In some cases, generally for large developments, the study area is defined following an analysis of development trips as described in Chapter 3.
4.3.2. Existing Roadway System
Detailed information regarding the physical and functional characteristics of the roadway system in the study area is provided in this section. Roadways to be described include all freeways, expressways, arterials and collectors that pass through the study area or pass within one-half kilometer of any part of the development site. If the development site is located in a downtown Abu Dhabi sector, a map of the sector is to be included and all local circulation roads in the sector are to be described. It is possible for some facilities outside the study area to be included in this description. Facilities may be added or subtracted at the discretion of the Roads Directorate.
Descriptions of facilities will include: • Name of facility;
• Physical characteristics of the facility (e.g., number of travel lanes, median, sidewalks, amenities, etc.);
• Posted speed limit;
• Location and type of control used of key junctions on the facility within the study area (a key junction is defined as an intersection or roundabout, signalized or unsignalized, or a ramp connecting two or more facilities classified as arterials, expressways or freeways);
• Parking facilities and regulations; and
• Existing peak traffic volumes on the facility within the study area or (if outside of the study area) at its nearest location to the development site for all peak hours to be analyzed in the traffic impact study.
An example of a facility description is as follows:
“Khalifa bin Zayed Street is an east-west arterial with dual carriageways separated by a raised median, with a posted speed limit of 60 kph. Each carriageway has three lanes, with additional turning lanes at signalized intersections. Khalifa bin Zayed Street serves mixed land uses in the study area. Within the study area, Khalifa bin Zayed Street has signalized intersections at Fourth Street, Liwa Street and Airport Road. Parking is prohibited on both sides of the street in the study area. Current daily and peak hour traffic volumes on Khalifa bin Zayed Street are shown in the following table.”
4.3.3. Existing Public Transport and Taxi Service
In Abu Dhabi, public transport currently consists of a regularly scheduled bus service. This section of the traffic impact study report will include a description of all bus transit lines providing service in the study area.
A description of each bus line including route number, alignment within the study area, terminal locations, frequency during peak hours and operating hours, should be included in the report. A map showing the routing of each of the bus lines in the study area may help clarify the narratives.
Any taxi station or major taxi staging area located in the study area should be described in the report.
4.3.4. Existing Pedestrian Facilities
Main pedestrian facilities such as crossings at signalized intersections, mid-block crossings, pedestrian underpasses, should be identified and marked on a map. Within sectors, sidewalks should be identified.
4.4. Data Collection/Traffic Count Requirements
Prior to any fieldwork, consultation between the Roads Directorate and the applicant is recommended to reach consensus on data to be used in the traffic impact study. This consensus is typically achieved at the initial meeting and documented in the Preliminary Plan.
Current year traffic counts are required for all key facilities analyzed in the traffic impact study. Counts conducted during the twelve months prior to approval of the Preliminary Plan will be considered current. Counts conducted earlier than twelve months but not more than 24 months before approval of the Preliminary Plan will require a growth factor adjustment before being considered current. The Consultant should develop appropriate growth factors and seek the Roads Directorate’s approval before their use.
Within sectors, peak-hour link volume counts are required for all segments of the local circulator roads. A segment is defined as the portion of the road between two other roads that are classified as local circulator roads or higher. Turning movement counts are required at all
junctions of local circulator roads. Sector/arterial driveways within the study area are key facilities that require peak hour counts.
Outside of the sectors, all junctions of collectors, arterials, expressways and freeways, including roundabouts (signalized and unsignalized) and intersections (signalized and all-way-stop-controlled) within the study area require peak hour turning movement counts (except ramps, which require directional counts). Freeways, arterials, and ramps within the study area require directional counts on all segments. A freeway or expressway segment is defined as the portion of the facility between interchanges/ramps or junctions with any other roadway facility.
Data to be used in the traffic impact study fall into one of two categories:
• Existing data to be obtained from the Roads Directorate; and
• New data to be collected by the applicant.
4.4.1. Existing Data to be obtained from the Roads Directorate
The consultant is to explore the availability of existing data relevant to the study with the Roads Directorate. The Roads Directorate may be in possession of data themselves or may refer the Consultant to another party. A charge may be levied by the Roads Directorate for providing certain data.
Data that may be available through the Roads Directorate include:
• Traffic counts;
• Maps showing land uses or street networks, or design plots of developments;
• Recent studies – Copies of recent traffic impact studies in the study area and area-wide studies that include the development site, if applicable.
• Plots of traffic volumes – Plots of current year and future year peak hour traffic volumes on freeways, expressways, arterials and collectors developed from Abu Dhabi Travel Demand Model assignments.
4.4.2. Data to be Collected by Applicant
Any data required for the traffic impact study and not available from the Roads Directorate must be collected by the applicant.
The assembly of available data should be accompanied by a detailed reconnaissance of the development site, area roadways, and the surrounding vicinity. This should include recording all relevant characteristics needed for the analysis, plus observations of existing traffic conditions. Only data required to address issues to be studied in the traffic impact study need to be collected.
Traffic volume counts must be collected in accordance with the procedure and requirements in these guidelines. Peak hour counts are to be collected for each peak hour to be evaluated in the traffic impact study. Morning peak hour counts are to be collected for the period from 6:30 to 8:30 AM. Noon peak hour counts are to be collected for the period from 10:30 AM to
12:30 PM. Afternoon peak hour counts are to be collected for the period from 1:30 to 3:30 PM. Evening peak hour counts are to be collected for the period from 6:30 to 8:30 PM.
All peak hour and daily counts are to be taken on Sundays, Mondays, and Tuesdays during the period beginning on 15 September and ending on 15 May, and are not to coincide with holidays or Ramadan. Counts taken at other times must be reviewed by the Roads Directorate, and may need to be adjusted before being used in the traffic impact study.
Turning Movement Counts at Signalized or Unsignalized Intersections
Turning movement counts at intersections are to be conducted manually, either via direct observation or through the use of continuous video surveillance. The counted volumes are to be documented in tabular format as shown in Figure 4-3. An Excel spreadsheet containing the table is to be put on a disk, CD, or other electronic medium and submitted to the Roads Directorate prior to or at the time the draft traffic impact study report is submitted.
Roundabout Counts
The format for reporting roundabout counts is the same as for intersections. Obtaining reliable turning movement counts at roundabouts is a task that requires careful planning and competent execution. Roundabout counts should only be conducted by trained personnel. Acceptable methodologies for conducting roundabout turning movement counts include:
• Video surveillance, provided the entire roundabout and entry/exit arms are visible continuously throughout the survey period;
• License plate surveys, provided the error rate is acceptable to the Roads Directorate; and
• Procedures documented in “Counting Roundabouts, A Model to Obtain Detailed Roundabout Turning Movements” (1).
Other procedures for counting roundabout turning movements will require review and approval of the Roads Directorate before being accepted.
Link Counts
Link counts include directional traffic volume counts on roadway segments and ramps. The counted volumes are to be documented in tabular format as shown in Figure 4-4. An Excel spreadsheet containing the table is to be put on a disk, CD or other electronic medium and submitted to the Roads Directorate prior to or at the time the draft traffic impact study report is submitted.
Acceptable methodologies for conducting link volume counts include:
• Manually, via direct observation;
• Manually, via video surveillance;
• Any other proven technology.
• Other procedures for counting link volumes will require approval of the Roads Directorate before being accepted.
4.5. Reporting Existing Levels of Service on Key Facilities
The analysis of existing conditions must include a summary of levels of service on all key facilities. Methodologies and procedures for determining levels of service are described in Chapter 3. All counts used in the report, whether obtained from the Roads Directorate or collected by the applicant, are to be included in an appendix to the report, both in printed and electronic format.
4.6. References
1. Kathairi, R. Mufti, A. Garib, E. Bierce, and B. Williams (2001). “Counting
Roundabouts: A Model to Obtain Roundabout Turning Movements”,
5.
ESTABLISHING FUTURE YEAR BASELINE
CONDITIONS
The first step in analyzing the impacts of a proposed new development is to establish future year baseline conditions. The future year baseline conditions represent a future year scenario without the proposed new development. This scenario will subsequently be compared to the with-development scenario to determine the development’s impacts. This chapter describes how the future baseline conditions are established.
5.1. Methods and Data Considerations
Future year baseline conditions are a quantitative assessment of traffic conditions in the study area in the horizon year(s), as determined in Chapter 3, assuming the proposed development is not built. Methods used for this step include modeling, manual, and mixed approaches that utilize the model for some steps and manual methods for others. Use of the model is most appropriate for very large developments with area-wide or regional impacts, and in situations in which the model forecasts have local credibility and network detail is consistent with that needed for site traffic analysis in the study area.
Manual methods are used for smaller developments, and/or near-future horizon years. A simple manual approach is to apply appropriate traffic volume growth rates in the study area, as described in this chapter. Other manual methods are described in ITE’s
Traffic Access and Impact Studies for Site Development the traffic impact handbook
(1).
For modeling approaches, the future year baseline should include all changes in land use and socio-economic conditions within the study area other than those related to the proposed development. Future baseline conditions are to be established for each horizon year to be evaluated in the traffic impact study.
Establishment of future baseline conditions includes:
• Obtaining approved assumptions regarding future year land use and population for related developments in the study area or at the regional level;
• Obtaining approved assumptions regarding future transportation improvements, including highway and public transportation projects;
• Determining future year baseline traffic volumes; and
• Evaluating future year baseline levels of service on key facilities.
5.2. Assumptions Regarding Future Year Land Use and
Population
Specific assumptions regarding future year land use and population are to be documented when the Abu Dhabi Travel Demand Model is used in the analysis, and when specific related developments are identified and integrated into the analysis. For
manual approaches, an assessment of new developments completed by the horizon year(s) may be limited to the study area. For modeling approaches, land use and population must be available or estimated for the entire region covered by the model.
5.2.1. Regional Growth Assumptions
When the Abu Dhabi Travel Demand Model is used in the analysis, the traffic impact study report should include an appendix showing assumptions for primary model input variables by zone and by sector, including:
• Number of residential units by type (including group quarters); • Square meters of non-residential land use by type; and
• Other data affecting trip generation such as special generators (airports, parks, etc.).
Any changes from the projected land uses in the model’s input database are to be noted in the traffic impact study report.
In the future year forecasts, the model input data may already include the development being proposed by the applicant. If this is the case, then the future year land use and demographic assumptions in the model’s input database for the zone (or zones) in which the proposed development is located needs to be appropriately modified such that the proposed development is not included in the baseline assumptions. These modifications must ensure that the intensity of land use and the number of residents of the new development are removed from the totals for these variables in the model database. The zonal totals were generally based on assumptions regarding growth and building height regulations for each sector. The rate of assumed growth within the model’s database for the zone, the size of the proposed development, and current Municipality density/building height regulations for the property to be developed, should all be considered in order to ‘subtract’ or remove correctly the assumed contribution of the new development to the future year database.
5.2.2. Related Developments in the Study Area
A related development is defined as a development in the study area that has been approved or is being considered for approval by the Municipality, and is considered by the Abu Dhabi Municipality and Town Planning Department as highly likely to be built and occupied by the horizon year, and is not included in the database of existing development at the time the Preliminary Plan is approved. A list of ongoing related developments should be prepared and, if a model approach is used for the traffic estimation, the model database should be modified to include them.
All related developments, both within the same sector as the proposed development and outside the sector but within the study area, are to be integrated into the future year baseline.
to be included in the description and incorporated into the transportation improvement assumptions for the future year baseline. A map showing the location of the related developments is also to be provided in the report. Procedures for integrating trips generated by related developments are provided in Section 5.4 of this chapter.
5.3. Assumptions Regarding Future Transportation
Improvements
The Municipality is continuously improving the transportation system in Abu Dhabi. Since these improvements often impact traffic conditions, it is important that the future year baseline incorporate all committed highway and public transportation improvements that will impact levels of service.
A committed transportation improvement is defined as a highway, transportation system management (TSM), public transportation, or transportation demand management (TDM) improvement (physical improvement, operational improvement, service improvement or policy action) that may affect levels of service within the study area and is considered by the Roads Directorate as highly likely to be implemented by the horizon year. Committed transportation improvements may be:
• Under construction;
• Funded for construction in an existing budget at the time the Preliminary Plan is approved;
• Project elements or mitigation measures for related developments; • Other improvements being considered by the Roads Directorate that
are considered highly likely to be implemented by the horizon year.
Identification of committed transportation improvements will typically be determined during the initial meeting and documented in the Preliminary Plan. If the committed transportation improvements are of sufficient regional significance that they are likely to substantially change traffic volumes on study area roadways, then a model run of the Abu Dhabi Travel Demand Model will be required to establish future year baseline conditions (refer to Section 5.4 of this chapter). The impact of substantial changes to the transportation system on traffic flows is more accurately estimated by the model, which redistributes traffic by taking into to account these changes in transportation system performance.
5.3.1. Highway and TSM Improvements
Highway and TSM improvements that may affect levels of service include physical improvements (such as new roads, roadway widening and adding lanes at intersections), signal synchronization and/or revisions to phasing and timing, adding new signals, converting roundabouts to signalized intersections, charging tolls, addition or removal of truck restrictions, and other improvements.
When the Abu Dhabi Travel Demand Model is used in establishing future year baseline conditions, all committed highway and TSM improvements are to be incorporated into the highway networks, wherever possible and reasonable, to determine future year baseline traffic volumes. In calculating future year baseline
levels of service, physical characteristics of committed transportation improvements (such as number of lanes and signal phasing) are to be integrated into the calculations as appropriate.
5.3.2. Public Transportation Service and TDM
Public transportation and TDM improvements that may affect level of service include new public transportation routes or connections (bus or rail), changes in service frequency, changes in public transportation and/or taxi fares, changes affecting public transportation vehicle speeds, creation of new transfer centers, policy actions to reduce the number of taxis in an area such as downtown, changes in parking costs and/or availability, and other improvements.
When the Abu Dhabi Travel Demand Model is used in establishing future year baseline conditions, all committed public transportation and TDM improvements are to be incorporated into the highway and/or public transportation networks and into the mode split model parameters, wherever possible and reasonable.
5.4. Determining Future Year Baseline Traffic Volumes
Future year baseline traffic volumes on specific roadways may be determined by the Abu Dhabi Travel Demand Model or manual methods. The choice of method depends upon the size of the proposed development and the size of the study area. Future year traffic volumes on local circulator roads will generally be determined using manual methods. Manual or modeling methods may be used to determine future year baseline traffic volumes on arterials and collectors when the study area boundary does not extend beyond the nearest arterial intersection. When the study area boundary includes more than one sector, the Abu Dhabi Travel Demand Model may be used to determine future year baseline traffic volumes on all freeways, expressways, arterials and collectors. However, the model representation of roads in the study area should first be reviewed and modified if possible to provide the necessary detail for an adequate analysis.
5.4.1. Manual Method for Determining Future Year Baseline Traffic Volumes
The manual method for determining future year baseline traffic volumes consists of three steps:
• Quantification of existing volume based on traffic count data; • Application of ambient growth rates; and
• Incorporation of traffic from related developments (see Section 5.2.2 above).
Procedures for quantifying existing traffic volumes based on traffic count data are provided in Chapter 4.