Transportation Impact Assessment Guidelines
Preface
The following TIA Guidelines have been developed jointly by the City’s Planning and Growth
Management and Public Works and Services departments in an effort to standardize and clarify what is required from a transportation perspective when dealing with development. On 27 September 2006 Council adopted the Guidelines as its policy for transportation impact assessment with the intent to ensure its goals and objectives, as present in the City’s Official Plan and Transportation Master Plan, are realized.
Although the guidelines are largely based on their predecessor, the RMOC 1995 Transportation Impact Study Guidelines, significant modifications have been made. It is important for those who are new to the Guidelines or have used the former version in the past, to take the time to read through these new Guidelines to recognize the changes and apply them as written.
Specific attention should be paid to:
• the need for consultants applying the guidelines and addressing development related transportation impacts, to be on the City’s new TIA Pre Qualified Consultant List;
• the requirement for an increased level of pre-consultation prior to the undertaking and submission of TIA studies and reports;
• the new levels of analysis and associated triggers to initiate them; and
• the requirement for an increase in analysis and reporting where resulting road modifications are required.
In applying the Guidelines as intended the development industry will see a quicker more efficient processing of the transportation component of the development approval process.
The City would like to acknowledge the work of Dillon Consulting, who through many hours of involvement have enabled the City to produce these guidelines, as well as the development and
consultant industry, and those of the public who participated in the consultation stages of this endeavor.
1. Introduction
The 2006 City of Ottawa Transportation Impact Assessment (TIA) Guidelines identify the scope and format of transportation analysis required to support applications for Development Approvals from the City of Ottawa. The TIA Guidelines document outlines:
1. The scope of analysis required to support development applications, depending on the type of development application and the size and scope of the proposal;
2. The types of analysis required to determine transportation system impacts resulting from
developments and acceptable levels of service for elements of the transportation network, consistent with Transportation Master Plan policies; and
3. The format recommended for TIA reports that will facilitate staff review and expedite timing for comments and approvals.
TIA reports are a critical part of the development review and approval process, as they are the primary tool for identifying the potential net effects from a development proposal. TIA reports establish:
• The impacts to the transportation system as a result of the proposed development;
• Transportation infrastructure and programs needed to mitigate impacts to an acceptable level; and
• Site design features needed to support system-wide transportation objectives.
The City of Ottawa recognizes three types of TIA reports, as described in Table 1.
Table 1 - Types of Transportation Impact Assessment Reports
Types of TIA Reports General Description of Report Scope Community
Transportation Study (CTS)
Community Transportation Studies (CTS) focus on assessing the ability of the local transportation network to support the proposed development. CTS determine the major network elements required to accommodate the proposed development at an acceptable level of service in every Phase (where the proposal has multiple phases).
Transportation Impact Study (TIS)
Transportation Impact Studies (TIS) focus on determining the specific infrastructure and programs needed to mitigate the impact of the proposed development on the local transportation network and establishing the site design features needed to support system-wide transportation objectives.
Transportation Brief (TB)
Similar to TIS, Transportation Briefs (TB) focus on determining the infrastructure and programs needed to mitigate the impact of the proposed development on the local transportation network and establishing the site design features needed to support system-wide transportation objectives. TB are generally undertaken for developments anticipated to have less significant impacts on the transportation network.
The City of Ottawa is a diverse place with a robust development industry in each of its urban (or infill), suburban and rural areas. TIA reports must acknowledge the circumstances surrounding the proposed development and be sensitive to the context of the application.
1.1 TIA Guidelines Structure
The 2006 City of Ottawa TIA Guidelines have been divided into seven sections:
• TIA Guidelines (base document)
• Appendix A - Methods for Demand Forecasting
• Appendix B - Community Transportation Study - Analysis Methods and Documentation Requirements
• Appendix C - Transportation Brief - Analysis Methods and Documentation Requirements
• Appendix D - Transportation Impact Study - Analysis Methods and Documentation Requirements
• Appendix E - Acceptable Parameters for Operational Review of Signalized Intersections
• Appendix F - Roadway Modification Approval Report – Needs and Formats
The front section of the report (base document) provides context for TIA reports related to the
Development Application process and details a number of triggers that determine the appropriate TIA report format. Appendices A through F outline methodologies for demand forecasting, the analysis and documentation for the three types of TIA reports, and the various parameters and acceptable standards in which the TIA work is completed.
Once the triggers in the base document are reviewed and the appropriate TIA report format is selected, the user prepares the TIA report according to the Methods for Demand Forecasting and relevant Analysis Methods and Documentation Requirements sections of the report. Figure 1 outlines the flow of
decisions.
2. Governing Planning Policies
2.1 Provincial Policy Framework
The Ontario Planning Act regulates and provides authority to the City of Ottawa to impose conditions when considering Planning or Development Applications. Additional authority and direction comes from the Provincial Policy Statement, the City of Ottawa Official Plan (and, through it, the Transportation Master Plan) and other regulatory documents (such as the Ontario Building Code, the Municipal Act, etc.).
The Planning Act authority to impose conditions varies by type of Development Application, with greater latitude for conditions available to staff in considering Official Plan Amendment, Zoning By-law
Amendment and Draft Plan of Subdivision or Condominium Applications. Possible conditions include:
• Property for abutting roads and public transit rights-of-way that are described in the municipal Official Plan;
• Facilities to provide access to and from the subject development, such as access ramps, curbing, and traffic direction signs;
• Off-street vehicular loading and parking facilities and access driveways; and
• Walkways and walkway ramps and all other means for pedestrian access.
Figure 1 – TIA Guidelines Process Diagram
2.2 City of Ottawa Official Plan
The City of Ottawa Official Plan contains policies that require the assessment of the adequacy of the complete transportation network to meet the needs of proposed developments. The Official Plan policies provide details on a number of transportation-related objectives, including a specific emphasis on transit, for the proposed development that are consistent with the City’s overall policy goals. The policies further establish the need for the preparation of a Transportation Impact Assessment report where the City deems that the proposed development may impact on the transportation network where the network includes the road, transit route, cycling and pedestrian components.
3. Process
3.1 Staff Consultation
The City of Ottawa Development Application process currently encourages a pre-consultation meeting between the developer and City staff. This meeting is typically used to convey staff expectations to the developer related to supporting documentation requirements. It is anticipated that Planning and Growth Management Department staff will confirm at this meeting the need for a transportation impact
assessment report in support of any development application and the required format of the assessment report (i.e., neighbourhood study, transportation impact study, or transportation brief).
As part of the pre-consultation, developers and their Consultants are encouraged to arrange a meeting with the City’s Infrastructure Approvals Division, Traffic and Parking Operations Branch and Transit Services Branch staff early in the preparation of transportation impact assessment reports to discuss and confirm the various parameters to be used in the subject analysis. At a minimum, contact will need to be made to verify the background developments and road and transit network improvements to be
considered in the report. Such meetings will be coordinated through the Infrastructure Approvals Division.
3.2 Assessment Updates
No report older than five years will be deemed sufficient documentation of potential impacts of a
development proposal. Where developments are phased, or reference is made to previous assessments, only reports completed within the five year period prior to the completion of the subject analysis will be accepted as relevant.
3.3 Qualifications of the Consultant
Consultants providing services associated with transportation impacts of land development are required to be on the City’s TIA pre qualified consultant list. This is a unique list for Transportation Impact
Assessment work and the associated application of the TIA Guidelines. As this is a City Council directive no development related transportation consultation or TIA submissions will be entertained from
consultants that are not on the pre qualified consultant list.
TIA submitted reports and/or briefs will require sign off from a project manager who is a licensed or registered professional with experience in the field of transportation planning and/or traffic operations.
Development and upkeep of the pre qualified list will be managed by the City’s Planning and Growth Management Department through its Infrastructure Approval Division.
3.4 Updates to the Transportation Impact Assessment Guidelines
The Deputy City Manager, Public Works and Services have the authority to amend these Guidelines to address minor or administrative matters as required. City Council and the development industry will be informed in a timely fashion of the minor or administrative matters that are being introduced.
4. Scope of Impact Analysis
4.1 Transportation Impact Assessment Report Approach
This section identifies the benchmarks to determine the type of TIA report required to support a
development application, where assessment triggers are associated with type of development, whether new or redevelopment, and its associated level of trip generation. The City of Ottawa does reserve the right to dictate the scope of the work required for assessment of transportation impacts associated with any development, regardless of the triggers identified below.
4.1.1 Development Application Process Triggers
The three types of TIA reports recognized by the City of Ottawa can be matched to distinct types of development applications, as is illustrated in Table 2, below.
Table 2 - TIA Report Approach for Various Types of Development Applications
Type of Development Application Type of TIA Study Required Sites
Official Plan Amendment (OPA) CTS Zoning By-law Amendment (ZBL) CTS
OPA / ZBL + Site Plan Combined CTS / TIS
Site Plan TIS / TB
Subdivisions
Draft Plan of Subdivision + recent CDP * No further study required Draft Plan of Subdivision without CDP CTS
Draft Plan + Registration Combined CTS / TIS
Registration TIS / TB
* No further study will be required at the Draft Plan of Subdivision stage if a Community Design Plan with an appropriate Community Transportation Study level of supporting transportation analysis has been prepared for the area within the last five years that assumes the same development concept for the lands as is being proposed in the Application.
4.1.2 Community Transportation Studies
Community Transportation Studies (CTS) are required for the following types of Development Applications:
• Official Plan Amendments;
• Zoning By-law Amendments; and
• Draft Plans of Subdivision or Condominium
Forecasted Site Trip Generation Triggers
OP and ZBL Amendment Applications
Where OPA and ZBL Applications are expected to generate fewer than 75 vehicles per hour (vph) [peak hour, two-direction site generated trips], the City of Ottawa will not require a TIA report, as it is satisfied that impacts on the adjacent transportation network can be accommodated without the need for roadway modifications. Table 3 presents information to assist with the estimation of site generated trips. For other land use types, trip generation estimates will be made assuming typical trip generation characteristics, as represented by the current edition of the Institute of Transportation Engineers (ITE) Trip Generation Manual.
Table 3 - Minimum Development Area Triggers for Community Transportation Studies OPA and ZBL Applications
Land Use Type Assumed Trip Generation Rate
No Study Required (Less than 75 vph
site trips)
CTS Required (In excess of 75 vph
site trips)
Residential 1.01 (PM) 0 – 75 units > 75 units
Office * 1.55 (AM) 0 – 4,500 m2 > 4,500 – 9,000 m2
Industrial * 0.98 (PM) 0 – 7,000 m2 7,000 m2
Fast Food * 53.11 (AM) 0 – 150 m2 > 150 m2
Destination Commercial * 5.00 (PM) 0 – 1,400 m2 > 1,400 m2
Convenience Market * 67.03 (AM) 0 – 100 m2 > 100 m2
* Units indicated are the gross floor area of proposed buildings
For all other OPA and ZBL Applications the analysis required to identify the potential impacts of the applications will be significant and will vary from application to application. As such, the study area and level of detail required for the impact assessment for CTS must be confirmed through
consultation with City staff. CTS are generally completed at a high level, concentrating on the basic functionality of the transportation network; assessment of operational and safety issues is typically not required.
When OPA/ ZBL applications are submitted in conjunction with Site Plan Control applications, the City will require an overall assessment of network capacity (CTS) in addition to the requirements of the TIS/ TB.
Draft Plans of Subdivision and Condominium
No transportation impact analysis will be required for Draft Plans of Subdivision or Condominium for developments with 75 units or fewer.
No transportation impact analysis will be required in support of a Draft Plan of Subdivision application if a Community Design Plan with an appropriate CTS level of supporting transportation analysis has been prepared for the area within the last five years (that assumes the same development concept for the subject lands as is being proposed in the Development Application). A CTS report will be required to support a Draft Plan of Subdivision application if no CDP has been prepared within the preceding five years and the development exceeds 75 units.
Typically, the City of Ottawa will require the preparation of a TIS or TB report to support an application for Final Plan Registration, to provide analysis details that were not addressed in the CTS report filed at the Draft Plan stage. Occasionally, applications are made simultaneously for Draft Plan of Subdivision/
Condominium and Final Plan Registration. When such a simultaneous application is made, and the development exceeds 75 residential units, the City will require an overall assessment of network capacity (CTS) in addition to the requirements of the TIS or TB.
Additional analysis will be required in the form of Transportation Impact Studies or Transportation Briefs to supplement the initial CTS at the time of Final Plan Registration for individual phases for Plans of Subdivision and Condominium.
CTS reports should be prepared according to the documentation requirements outlined in Appendix B – Community Transportation Study Analysis Methods and Documentation Requirements.
4.1.3 Transportation Impact Studies and Transportation Briefs
Transportation impact studies (TIS) and briefs (TB) are required for the following types of Development Applications:
• Registration of Plans of Subdivision or Condominium; and
• Site Plan Control.
Applications for Registration of Plans of Subdivision and Site Plan Control generally represent a more developed and immediate development concept; therefore, the City of Ottawa is concerned about transportation network operational and safety issues in addition to capacity concerns. Triggers reflecting these concerns have been established (see Table 4). Any one of the first three triggers (i.e., the operational / safety triggers) would drive the need to undertake a TIS, regardless of volume of site traffic generated. In the absence of operational/ safety concerns, the capacity triggers (volume of site traffic generated) determine the appropriate level of analysis.
Table 4 - Triggers for Transportation Briefs and Transportation Impact Studies
Issues to Consider Type of TIA Report Required No Assessment Transportation
Brief
TIS
Operational / Safety Triggers a. Safety/ operations
concerns
on boundary roads
n/a n/a Required
b. Drive-thru facility n/a n/a Required
c. Roadway modifications proposed
n/a n/a Required
Forecasted Site Trip Generation Triggers d. Volume of site traffic
generated
0 – 75 vph 76 vph – 150 vph > 150 vph
Land Use Type
Residential 0 – 75 units 76 – 150 units > 150 units
Office * 0 – 4,500 m2 4,501 – 9,000 m2 > 9,000 m2
Industrial * 0 – 7,000 m2 7,001 – 14,000 m2 > 14,000 m2
Fast Food * 0 – 150 m2 151 – 275 m2 > 275 m2
Destination Commercial * 0 – 1,400 m2 1,401 – 2,800 m2 > 2,800 m2
Convenience Market * 0 – 100 m2 101 – 200 m2 > 200 m2
* Units indicated are the gross floor area of proposed buildings Safety/Operational Concerns Triggers
The City of Ottawa will require TIS reports for developments if safety and/or traffic operations in the vicinity of access points are of concern. Typical conditions that would generate access-related safety or
operational concerns include those outlined below (this list is not exhaustive; it is representative of the most common conditions):
• Operating Speeds on the adjacent road exceed 80 km/hr (typically rural);
• The adjacent road is designated part of the Transit Priority or Rapid Transit Network (typically urban/suburban);
• Horizontal/ vertical curvature on the adjacent road at proposed access limits sight lines;
• Traffic volumes on the adjacent road are significant enough to cause queuing, storage, or delay concerns;
• The frequency of collisions meets or exceeds six (6) in any particular pattern over a three year period on development-affected roadways, and
• Access is within area of influence of an adjacent traffic signal, defined as within:
o 300 m of the signal in rural conditions;
o 25 m of the end of taper at an intersection with auxiliary lanes under urban/ suburban conditions;
or
o 150 m of a signalized intersection without tapers/ flares under urban/suburban conditions.
Regardless of the size or location of the development, a TIS report will be required for all proposals that include drive-thru facilities, to demonstrate that sufficient on-site storage is being provided and that no impacts will occur on public streets. A TIS report will also be required for all proposals that include roadway modifications to the boundary roads.
Forecasted Site Trip Generation Triggers
As indicated in Table 4, where Development Applications are expected to generate fewer than 75 vehicles per hour (vph) [peak hour, two-direction site generated trips], and no operational/ safety triggers apply, the City of Ottawa will not require a TIA report, as it is satisfied that impacts on the adjacent transportation network can be accommodated without the need for roadway modifications. Table 4 presents information to assist with the estimation of site generated trips. For other land use types, trip generation estimates will be made assuming typical trip generation characteristics, as represented by the current edition of the Institute of Transportation Engineers (ITE) Trip Generation Manual.
Additionally, where Development Applications are expected to generate between 75 and 150 vehicles per hour (vph) [peak hour, two-direction site generated trips], and no operational/ safety triggers apply, a Transportation Brief may be sufficient.
TIS and TB reports should be prepared according to the documentation requirements outlined in
Appendix C –Transportation Brief Analysis Methods and Documentation Requirements and Appendix D – Transportation Impact Study Analysis Methods and Documentation Requirements.
4.2 Types of Analysis
The following describes the types of analysis to be undertaken to assess the potential impacts of the proposed development on the transportation system. Accepted methodologies for undertaking the required analysis are documented in this report under Appendices A through D:
• Appendix A – Methods for Demand Forecasting
• Appendix B – Community Transportation Study Analysis Methods and Documentation Requirements
• Appendix C – Transportation Brief Analysis Methods and Documentation Requirements
• Appendix D – Transportation Impact Study Analysis Methods and Documentation Requirements 4.2.1 System Congestion and Capacity
An evaluation is required of the projected level of service/ capacity of the local road network elements that will be affected by site generated transportation demands during any or all of the relevant time periods and scenarios.
4.2.2 System Operations and Safety
Transportation Impact Studies and Transportation Briefs must consider potential operational and safety concerns through intersections, on road or transit segments or on ramps that will be created or affected by site generated transportation demands during any or all of the relevant time periods and scenarios.
Community Transportation Studies are generally completed at a high level, concentrating on the basic functionality of the transportation network; assessment of operational and safety issues is not required.
4.2.3 Non-Auto Modes
All TIA reports will assess the provisions made in the development proposal for all non-auto modes, in keeping with the policy directions established by the Official Plan and Transportation Master Plan.
Elements of the proposal that support rapid and conventional transit ridership, cycling, and pedestrian movements on the study area transportation network must be identified. The OP requires that developers determine the method and means by which the development, as well as adjacent areas, can be efficiently and effectively serviced by transit. Pedestrian and bicycle network continuity should be considered, as should Official and Transportation Master Plan policy requirements related to the provision of
infrastructure to promote non-auto modes.
4.2.4 On-Site Design and Operations
Transportation Impact Studies and Transportation Briefs must consider the ability of the site to support the City of Ottawa’s transportation policy objectives. The proposed layout of the site will be considered and the potential for on-site traffic operations to affect the safe and efficient operation of the adjacent roads will be identified.
The City recognizes that there are a number of legislative and By-law requirements and physical site constraints that are considered in the development of a Site Plan (e.g., Building Code, Zoning By-law, etc). The transportation objectives, on-site circulation and access may be superseded by other governing regulations.
4.2.5 Community Impacts
An evaluation of the potential for community impacts resulting from the proposed development is
required. The focus of the analysis will be on the potential for neighbourhood infiltration by site generated traffic and the proposed scheme for accommodating the parking demand generated by the site.
4.2.6 Transportation Demand Management
A Transportation Demand Management (TDM) plan must be prepared for the proposed development, identifying links to City’s TDM initiatives and mechanisms for integrating the proposed development into the existing services and programs.
4.3 Analysis Parameters
4.3.1 Study Area
The City of Ottawa is a diverse place with a robust development industry in each of its urban (or infill), suburban and rural areas. The intent of TIA reports is to identify impacts and appropriate mitigation, acknowledging the circumstances surrounding the proposed development. The Study Area for TIA reports will be established considering:
• The location and type of proposed development;
• The existing traffic volumes on the adjacent road network; and
• The existing transportation network adjacent to the site.
The default study area will be all access points/ driveways to the proposed development and all elements of the transportation network within 1 kilometre of the proposed site (in all directions) that are impacted by development traffic. Where the TIA report addresses impacts related to an infill development staff may be prepared to review the required study area for the report.
4.3.2 Time Periods
The transportation impact assessment report must consider two conditions to fully determine the effects of the development proposal:
1. The impact of the development on the peak conditions of the adjacent transportation infrastructure;
and
2. The impact of the peak site generated traffic volumes on the adjacent transportation infrastructure.
Typically, the AM and PM peak weekday peak hours of the adjacent streets will constitute the “worst case” of the combination of site-related and background traffic; however in the case of retail,
entertainment, recreational, religious, institutional, or special events uses, Thursday / Friday evening, Saturday, Sunday or site peak hours may also require analysis. As part of the pre-consultation process prior to commencing the analysis, the consultant should determine and justify the selected time periods for analysis in conjunction with City staff.
4.3.3 Horizon Years
The City of Ottawa requires that all transportation impact assessments consider two horizon periods for analysis:
1. buildout/full occupancy of the development (full occupancy where it is not the same as buildout); and 2. buildout/full occupancy + 5 years.
Where development of a site is proceeding in phases, analysis of potential impacts should be completed for each of the phases proposed for the development. In the case of phased development, the need to complete a “buildout + 5 years” analysis may be waived by the City, depending on the timing of the phases
Appendix A - Methods for Demand Forecasting
A1 Introduction
The Methods for Demand Forecasting appendix establishes the accepted methodologies for forecasting the transportation demands that are to be used in the preparation of a Transportation Impact Assessment Report whether the report is a CTS, TB or TIS.
The methodologies identified in this section should be read in conjunction with the direction and understanding of the base conditions of the TIA as identified in the TIA Guidelines report.
A2 Background Traffic
Anticipated background conditions should be confirmed with City of Ottawa staff prior to undertaking the demand forecasting component of the transportation impact assessment. Three main parameters need to be confirmed with City staff:
• Potential / planned changes to the study area road and transit route networks;
• Rate of general background growth on the arterial network; and
• Other anticipated developments in the study area.
These parameters are discussed individually below.
A2.1 Changes to the Study Area Transportation Network
The City of Ottawa anticipates significant changes to its transportation network over time, specifically the road and transit route components. These changes need to be reflected in the future background traffic volumes to create an appropriate foundation for the assessment of the impacts of the subject
development. Planned transportation network changes are identified in the Schedules of the City of Ottawa’s Official Plan and in the City’s Transportation Master Plan; however the City’s Capital Budget Plan is the only accepted source for the anticipated timing of major projects. Smaller scale transportation projects may also be associated with other local developments and should be accounted for, where they impact the assignment of traffic from the subject development.
The Consultant must project and demonstrate the impact of the planned network changes on traffic and travel patterns, particularly those associated with new facilities (as opposed to widened facilities).
Significant assumptions related to the reassignment of traffic patterns must be detailed in the Consultant’s report. Input may be available from the City of Ottawa’s Long-Range Transportation Model.
A2.2 General Background Growth
The rate of growth in background traffic should be established through one of the following methods:
• Regression analysis of historical traffic growth;
• A growth rate based on an area or neighbourhood transportation study;
• Estimation of screenline growth from the City of Ottawa’s Long-Range Transportation Model; or
• Projected rates of growth in area population and/or employment.
Where growth in the area of the development under consideration has been significant in the recent past or will be significant within the horizon years of the assessment, regression-based methods may be inappropriate.
Historical traffic volume data and population/ employment data can be obtained where available from the City of Ottawa’s Public Works and Services and Planning and Growth Management Departments, respectively.
Direction regarding the appropriate methodology for estimating background traffic growth should be obtained from City of Ottawa Planning and Growth Management Department Staff. For information regarding current and future transit ridership levels, City of Ottawa Transit Services Branch staff may be consulted.
A2.3 Other Study Area Developments
All significant developments under construction, approved, or in the approval process within the study area which are likely to occur within the identified horizon years must be identified and recognized in the
subject transportation impact assessment report. Planning and Growth Management Department staff will identify the land-use type and magnitude of the probable future developments in the horizon years.
A3 Site Development Traffic
All trip generation, trip distribution, and trip assignment assumptions should be in accordance with standard accepted techniques and based on local conditions. Sources should be well documented and any assumptions that may be considered as being aggressive or less than conservative should be rigorously justified. Sensitivity analysis should be completed for any parameter surrounded by significant uncertainty.
A3.1 Trip Generation
Consultation with City of Ottawa staff is recommended to ensure that appropriate trip generation rates and assumptions are being employed in the transportation impact assessment. All trip generation assumptions (i.e., basic rates and adjustment factors) must be completely rationalized and justified within the transportation impact assessment report, including the source of trip generation rate information and the rationale as to its applicability. Sample calculations are to be provided where first principles
assumptions are used and/or multiple adjustment factors are adopted.
A3.1.1 Basic Rates
Supported trip generation methodologies include, in order of preference:
1. The updated TRANS trip generation manual (anticipated to be available in 2007);
2. Trip generation surveys from similar developments in the City. Surveyed sites should have similar operating and market characteristics to the development proposal (supporting statistical analysis demonstrating the relevance of surveyed rate would be beneficial);
3. Institute of Transportation Engineers (ITE) Trip Generation rates, as documented in the latest edition of the Trip Generation Manual or in other technical sources from ITE; and
4. “First principles” calculations of anticipated trips to/ from the site.
A3.1.2 General Adjustment Factors
A number of adjustment factors should be considered in addition to the basic site trip generation rate.
Deduction of Existing Site Trips – Total Redevelopment Scenario
Where the development proposal is for the total redevelopment of an existing site (i.e., the existing use is removed and replaced by the proposed use), it is acceptable to deduct existing site trips generated by the existing use from the projected site trips to calculate the net impact on the transportation system.
Similarly, where the application is for an expansion to an existing site, it is appropriate to consider only the additional trips to be generated by the expanded site. However, operational analysis of site accesses must consider the total volume of site traffic following redevelopment (i.e., existing + new trips).
Transit/Cycling/Pedestrian Share
Modal shares for the proposed development will vary from location to location across the City. Trip generation rates taken from local surveys may need to be adjusted to reflect the difference between the source modal share and the modal share that can be expected given the location of the proposed site.
Many of the trip generation rates quoted in the ITE Trip Generation Manual represent locations with low modal shares for transit/ cycling/ pedestrians; given Ottawa’s commitment to these modes it may be reasonable to adjust trip generation rates from this source.
Figure 3.7 on page 26 of the 2003 City of Ottawa Transportation Master Plan (TMP) provides data on transit modal splits for several planning screenlines around the City. Given the short-term nature of most transportation impact assessments, significant deviation from the 2002 transit modal split levels shown in TMP Figure 3.7 that cannot be justified by commensurate increases in transit service will not be
supported. Some increases may still be acceptable, given that the planned transit modal split increases to the 2021 levels shown in TMP Figure 3.7 in the City of Ottawa will be achieved over time. Trip generation calculations should assume logical changes to, or growth in, existing transit/ cycling/
pedestrian modal shares over time.
Transportation Demand Management (TDM)
The challenge in applying TDM reductions to site trip generation rates is the difficulty in isolating the effects of Transportation Demand Management (TDM) on a single development. The 2003 City of Ottawa TMP update targeted a 5.5% reduction in all peak hour traffic volumes as a result of a
combination of trip elimination (3%); time shifting (1%); and increases in auto occupancy (1.5%) by the year 2020. Application of TDM adjustment factors to an individual site will need to be justified and commensurate program and infrastructure requirements of the developer must be identified.
A3.1.3 Commercial Adjustment Factors
Typical trip generation rates represent the total volume of traffic measured at the driveways to the
proposed development. For many commercial developments, driveway volumes include a mixture of trips that are new to the road network and trips that are attracted from the adjacent roadway or adjacent developments.
Pass-by trips
Trips attracted from the adjacent roadway are usually referred to as “pass-by” trips. Pass-by trips are already on the adjacent road traveling from primary origin to ultimate destination, and make an
intermediate stop at the proposed development to execute a transaction. For example, a driver may stop at a convenience market or gas station on his/ her way home from work. The trip in terms of market is not a new trip added to the road system; it is temporarily diverted from the adjacent traffic stream. If pass-by trip assumptions are used as an adjustment factor in determining trip generation, these trips must still be accounted for in the turning movements into and out of the site.
The Recommended Practices appendix to the ITE Trip Generation Manual (7th Edition) suggests acceptable pass-by trip percentages. Deviations from these pass-by percentages must be defended.
Synergy/Internalization
Trips attracted to two or more uses on the same site are usually referred to as having “synergy”. For example, a trip to a multi-use site may be destined to both a grocery store and a restaurant. Synergy between uses should reduce the number of trips generated by the site, as compared to when site traffic is calculated by summing the trip generation forecasts for the individual components of the site.
The rate of internalization for multi-use sites varies from site to site, depending on the combination of uses. Because of this, no “typical rates” data is available for the rate of trip internalization on multi-use sites. Assumptions in transportation impact assessments must be justified and (preferably) supported by the results of site trip generation surveys.
A3.2 Trip Distribution
The directions from which traffic will approach and depart the site can vary depending on several location- specific factors, including:
• Size and type of the proposed development;
• Surrounding land uses, particularly location of competing developments;
• Distribution of population and employment; and
• Characteristics of the surrounding road network.
The trip distribution assumptions should be justified in the report, and may be based on one or more of the following:
• Origin-destination surveys or comprehensive travel surveys;
• Market studies;
• Census tract data;
• Population and employment distribution data provided by Planning and Growth Management Department staff;
• Output from the City of Ottawa’s Long Range Transportation Model; and
• Existing/ anticipated travel patterns.
A3.3 Trip Assignment
Traffic assignments should consider logical routings, available, current and projected roadway capacities, and travel times. Traffic assignments may be estimated using a transportation planning model or “hand assignment” based on knowledge of the study area.
Existing access rights should not be assumed where the TIA report concerns redevelopment of an existing property. City staff will review the proposed land use and conditions on the adjacent transportation network and identify an acceptable access pattern.
Appendix B - Community Transportation Study Analysis Methods and Documentation Requirements
B1 Introduction
The Community Transportation Study - Analysis Methods and Documentation Requirements appendix establishes the accepted methodologies for analyzing development impacts, determining required mitigation measures and documenting the results for Community Transportation Studies (CTS).
Community Transportation Studies (CTS) focus on assessing the ability of the local transportation network to support the proposed development. CTS determine the major network elements required to accommodate the proposed development at an acceptable level of service in every Phase (where the proposal has multiple phases).
The methodologies identified in this section should be read in conjunction with the direction and
understanding of the base conditions of the TIA as identified in the TIA Guidelines report and Appendix A.
B2 Analysis Methods
B2.1 System Congestion/Capacity
B2.1.1 Screenline Analysis
CTS must include a screenline analysis. Screenline analysis is a comparison of forecasted demands and lane capacities on the major road network (including freeways, arterial roads and major collector roads) connecting the site to the area transportation network. Typical lane capacities should be established based on the Official Plan designation for the local road classifications and the general characteristics of
the roads (e.g., suburban with limited access, urban with on-street parking, etc.). Mitigation measures in the form of additional lane capacity must be identified where V/C for the screenline exceeds 0.90, except in the Urban Core, where 1.0 is acceptable.
Screenline analysis should consider new capacity that is planned to occur within the horizon of the development. Planned transportation network changes are identified in the Schedules of the City of Ottawa’s Official Plan and in the City’s Transportation Master Plan; however the City’s Capital Budget Plan is the only accepted source for the anticipated timing of major projects.
Transit demands should also be considered, based on the assumed transit modal split, and transit network requirements identified. Consideration should be given to the Official Plan Schedules showing the Rapid Transit and Transit Priority networks.
B2.1.2 Intersection Capacity
An evaluation is required of any critical intersection within the study area that will potentially be affected by site generated traffic volumes during any or all of the relevant time periods and scenarios. Summaries are to be provided in tabular format clearly identifying intersection performance under existing and future traffic conditions. Where development is anticipated to proceed in phases or stages, projected
performance for all intersections must be documented for the end of each phase.
Detailed output from analysis software is to be provided in an appendix to the report and copies of the electronic files should be provided on CD. Appendix E outlines parameters to be used in operational analysis of signalized intersections.
All volume to capacity (V/C) calculations relating to future conditions should be determined using signal timing optimized for the volume conditions being studied. The V/C ratio for an intersection is defined as the sum of equivalent volumes for all critical movements divided by the sum of capacities for all critical movements assuming that the V/C ratios for critical movements can be equalized. In cases where minimum pedestrian phase times prevent equalizing the level of service for critical movements, then the V/C ratio for the most heavily saturated critical movement should be considered as the V/C ratio for the intersection. Adjustment for the impact of pedestrian activated control is permitted provided detailed supporting analysis including projected pedestrian volumes is provided and discussed in advance with traffic engineering staff.
The Consultant must undertake at least one hour of observations during peak traffic conditions to verify that the traffic volumes through the intersections reflect existing demands and to identify unusual
operating conditions. Timing of observations and conditions observed should be documented in writing in the report.
The City of Ottawa has adopted criteria that directly relate the volume to capacity (V/C) ratio of a signalized intersection to a level of service (LoS) rating. These categories are;
LEVEL OF SERVICE VOLUME TO CAPACITY RATIO
A 0 to 0.60
B 0.61 to 0.70
C 0.71 to 0.80
D 0.81 to 0.90
E 0.91 to 1.00
F > 1.00
Intersection evaluations should identify:
• Signalized Intersections – V/C ratios for the overall intersection, as defined above, and individual movements; and
• Unsignalized Intersections - Level of service (LOS) where the LOS is between A and E; V/C where capacity is based on gap analysis if intersection LOS is F.
Mitigation measures in the form of the addition of lane capacity and/or signal timing/ phasing adjustments will be required where V/C ratios for signalized intersections exceed 0.90, as defined above, except in the Urban Core, where 1.0 is acceptable.
Existing signal timing information such as phasing, pedestrian minimums and clearance intervals must be used as a base to analyze the existing capacity of signalized intersections. This signal timing data should be obtained from the City of Ottawa Traffic Operations Division. Operational design of the signals
analyzed should be in accordance with City of Ottawa signal operation practices.
In cases where roadways have closely spaced signals and especially when there are heavy turning movements, the analysis should confirm that storage limitations will not prevent signalized intersections from operating at the predicted V/C ratio.
Traffic control device and auxiliary lane warrants should be completed and documented in the CTS report, as required.
The City of Ottawa prefers that analysis be completed using the Highway Capacity Software (HCS version 4d or later), or Synchro (version 5 or later). Should a consultant wish to utilize a software
package other than those listed above, prior approval must be obtained from the City’s Traffic Operations Division.
B2.2 Provision for Non-Auto Modes
An assessment is required of the provisions made in the development proposal for all non-auto modes, in keeping with the policy directions established by the Official Plan and Transportation Master Plan.
Elements of the proposal that support rapid and conventional transit ridership, cycling, and pedestrian movements on the study area transportation network must be identified. Section 4.3, 5(b) of the OP requires that developers determine the method and means by which the development, as well as adjacent areas, can be efficiently and effectively serviced by transit. Pedestrian and bicycle network continuity should be considered, as should Official and Transportation Master Plan policy requirements related to the provision of infrastructure to promote non-auto modes.
An assessment of potential impacts on transit operations must be undertaken for current transit routes and any service changes proposed by the applicant and where the site accesses connect to or cross elements of the City’s Rapid Transit or Transit Priority Networks (see Schedules of the Transportation Master Plan and/or Official Plan for the City’s transit networks). The assessment will identify the potential for increased delay to transit vehicles, safety concerns/ conflicts with transit vehicles, and any impacts on stations or stops.
Gaps in pedestrian and cycling network continuity, due to missing infrastructure or as a result of winter maintenance, should be identified. That is, the Consultant should note where obvious gaps in the networks would exist as a result of the site pedestrian and cycling facilities not connecting or being accessible or having access to pedestrian and/or cycling facilities on the existing transportation network.
Identification of these gaps will assist City staff in approving development related transportation infrastructure and/or prioritizing its own program of pedestrian and cycling facility construction and maintenance.
A detailed assessment of pedestrian facility level of service will be required in the vicinity of the site where the development is expected to produce significant pedestrian volumes. City staff will identify situations where this will be an issue. Additional sidewalk or facility width may be required in such circumstances.
B2.3 Community Concerns
B2.3.1 Community Transportation Impacts
The CTS report will review the transportation network in the vicinity of the proposed development and identify potential neighbourhood infiltration routes. Focusing on these routes in the study area, the report will identify site-related traffic impacts on potentially affected neighbourhood streets during both the commuter peak and the projected site peak and an appropriate mitigation strategy, where one is required.
B2.3.2 Parking Impacts
For developments that generate significant auto parking demand the TIS report will review the site- generated parking demand and will demonstrate an appropriate parking strategy for the development.
B2.4 Transportation Demand Management
A Transportation Demand Management (TDM) plan must be prepared for the proposed development, identifying links to City’s TDM initiatives and mechanisms for integrating the proposed development into the existing services and programs. The City’s TDM Section, within the Public Works and Services Department, is available to assist in developing a TDM plan.
B3 Documentation and Reporting
The structure and format of the Community Transportation Study should follow the guidelines outlined in this document, as applicable. The following is a suggested report structure:
Report Context
Description of the development (include all of the following that are known at the time of the application):
• Municipal address;
• Location relative to major elements of the existing transportation system (e.g., the site is located in the southwest quadrant of the intersection of Main Street/ First Street, 600 metres from the Maple Street Rapid Transit Station); Existing land uses or permitted use provisions in the Official Plan, Zoning By-law, etc.;
• Proposed land uses and relevant planning regulations to be used in the analysis;
• Proposed development size (building size, number of residential units, etc.) and location on site;
• Estimated date of occupancy;
• Planned phasing of development;
• Proposed number of parking spaces (not relevant for Draft Plans of Subdivision); and
• Proposed access points and type of access (full turns, right-in/ right-out, turning restrictions, etc.).
• Study area;
• Time periods and phasing; and
• Horizon years (include reference to phased development).
The CTS must include a key plan that shows the general location of the development in relation to the surrounding area. The CTS must also provide a draft site plan or development concept of a suitable scale that shows the general location of the development and the proposed access locations. If the proposed development/ redevelopment is to be constructed in phases, a description must be provided for each phase, identifying the proposed timing of implementation.
Existing Conditions
• Existing roads and ramps in the study area, including jurisdiction, classification, number of lanes, and posted speed limit;
• Existing intersections, indicating type of control, lane configurations, turning restrictions, and any other relevant data (e.g., extraordinary lane widths, grades, etc.);
• Existing access points to adjacent developments (both sides of all roads bordering the site);
• Existing transit system, including stations and stops;
• Existing on- and off-road bicycle facilities and pedestrian sidewalks and pathway networks;
• Existing system operations (V/C, LOS); and
• Major trip generators/ attractors within the Study Area should be indicated.
The CTS report must include figures documenting the existing travel demands by mode. A photographic inventory of the transportation network elements in the vicinity of the proposed access points would be beneficial to staff in their review of the Consultant’s report.
Demand Forecasting
• General background growth;
• Other study area developments;
• Changes to the study area road network;
• Trip generation rates;
• Trip distribution and assignment:
o include figures documenting total future travel demands by mode for each horizon year.
Impact Analysis
• Network Capacity Analysis;
• Non-auto network connections and continuity;
• Potential for community impacts, and
• TDM.
Mitigation Measures and Site Design Characteristics
The CTS must identify all mitigation measures required to offset network impacts from the development.
The CTS must also identify key site design features required to implement the Official Plan and Transportation Master Plan policies regarding site development.
The CTS must include all of the following, where they are required by the subject development:
• Major network elements required to bring the screenlines to or below acceptable operating guidelines, and comments regarding consistency of the requirements with the Transportation Master Plan and Capital Budget;
• Location and timing of proposed changes to existing traffic controls at intersections (e.g., new traffic signals, Stop signs, etc.);
• Location and timing of new intersections, including proposed traffic control measures (e.g., traffic signals, etc.);
• Requirements for new auxiliary lanes;
• Mitigation measures required to offset impacts on the surface and Rapid Transit networks;
• New or modified elements of the bicycle and pedestrian networks;
• Community impact mitigation measures;
• Demonstration that Official Plan policies regarding transit-supportive developments have been incorporated appropriately; and
• Proposed TDM features or programs to support the site development.
Appendix C - Transportation Brief Analysis Methods And Documentation Requirements
C1 Introduction
The Transportation Briefs - Analysis Methods and Documentation Requirements appendix establishes the accepted methodologies for analyzing development impacts, determining required mitigation measures and documenting the results for TIA related transportation briefs.
Transportation Briefs (TB) focus on determining the infrastructure and programs needed to mitigate the impact of the proposed development on the local transportation network and establishing the site design features needed to support system-wide transportation objectives. TB are generally undertaken for developments anticipated to have less significant impacts on the transportation network.
The methodologies identified in this section should be read in conjunction with the direction and
understanding of the base conditions of the TIA as identified in the TIA Guidelines report and Appendix A.
C2 Analysis Methods
C2.1 System Congestion/ Capacity
C2.1.1 Existing Intersection Capacity
An operational evaluation of signalized and unsignalized intersections that will be affected by site generated traffic volumes during any or all of the relevant time periods and scenarios is required.
Summaries are to be provided in tabular format clearly identifying intersection performance under existing conditions. Detailed output from analysis software is to be provided in an appendix to the report and copies of the electronic files should be provided on CD. Appendix E outlines parameters to be used in operational analysis of signalized intersections.
The volume to capacity (V/C) ratio for an intersection is defined as the sum of equivalent volumes for all critical movements divided by the sum of capacities for all critical movements assuming that the V/C ratios for critical movements can be equalized. In cases where minimum pedestrian phase times prevent equalizing the level of service for critical movements, then the V/C ratio for the most heavily saturated critical movement should be considered as the V/C ratio for the intersection. Adjustment for the impact of pedestrian activated control is permitted provided detailed supporting analysis including projected
pedestrian volumes is provided and discussed in advance with traffic engineering staff.
The Consultant must undertake at least one hour of observations during peak traffic conditions to verify that the traffic volumes through the intersections reflect existing demands and to identify unusual
operating conditions. Timing of observations and conditions observed should be documented in writing in the report.
The City of Ottawa has adopted criteria that directly relate the volume to capacity (V/C) ratio of a signalized intersection to a level of service (LoS) rating. These categories are;
LEVEL OF SERVICE VOLUME TO CAPACITY RATIO
A 0 to 0.60
B 0.61 to 0.70
C 0.71 to 0.80
D 0.81 to 0.90
E 0.91 to 1.00
F > 1.00
Intersection evaluations should identify:
• Signalized Intersections – V/C ratios for the overall intersection, as defined above, and individual movements; and
• Unsignalized Intersections - Level of service (LOS) where the LOS is between A and E; V/C where capacity is based on gap analysis if intersection LOS is F.
Mitigation measures in the form of signal timing/ phasing adjustments will be required where V/C ratios for signalized intersections exceed 0.90, as defined above, except in the Urban Core, where 1.0 is
acceptable.
Existing signal timing information such as phasing, pedestrian minimums and clearance intervals must be used as a base to analyze the existing capacity of signalized intersections. This signal timing data should be obtained from the City of Ottawa Traffic Operations Division. Operational design of the signals
analyzed should be in accordance with City of Ottawa signal operation practices.
In cases where roadways have closely spaced signals and especially when there are heavy turning movements, the analysis should confirm that storage limitations will not prevent signalized intersections from operating at the predicted V/C ratio.
The City of Ottawa prefers that analysis be completed using the Highway Capacity Software (HCS version 4d or later), or Synchro (version 5 or later). Should a consultant wish to utilize a software
package other than those listed above, prior approval must be obtained from the City’s Traffic Operations Division.
C2.1.2 Existing Queuing Capacity at Major Intersections
Intersection evaluations should identify projected queue lengths and available storage for auxiliary and through lanes on all approaches.
C2.1.3 Impacts on Congestion/ Capacity
A qualitative assessment of potential impacts from the site development on system capacity is required.
The analysis should reference existing surplus capacity and storage for queues (assuming surplus capacity exists) and justify the ability of the network to accommodate the development without the need for network modifications.
C2.2 Provision for Non-Auto Modes
An assessment is required of the provisions made in the development proposal for all non-auto modes, in keeping with the policy directions established by the Official Plan and Transportation Master Plan.
Elements of the proposal that support rapid and conventional transit ridership, cycling, and pedestrian movements on the study area transportation network must be identified. Section 4.3, 5(b) of the OP requires that developers determine the method and means by which the development, as well as adjacent areas, can be efficiently and effectively serviced by transit. Pedestrian and bicycle network continuity should be considered, as should Official and Transportation Master Plan policy requirements related to the provision of infrastructure to promote non-auto modes.
An assessment of potential impacts on transit operations must be undertaken for current transit routes and any service changes proposed by the applicant and where the site accesses connect to or cross elements of the City’s Rapid Transit or Transit Priority Networks (see Schedules of the Transportation Master Plan and/or Official Plan for the City’s transit networks). The assessment will identify the potential for increased delay to transit vehicles, safety concerns/ conflicts with transit vehicles, and any impacts on stations or stops.
Gaps in pedestrian and cycling network continuity, due to missing infrastructure or as a result of winter maintenance, should be identified. That is, the Consultant should note where obvious gaps in the networks would exist as a result of the site pedestrian and cycling facilities not connecting or being accessible or having access to pedestrian and/or cycling facilities on the existing transportation network.
Identification of these gaps will assist City staff in approving development related transportation infrastructure and/or prioritizing its own program of pedestrian and cycling facility construction and maintenance.
C2.3 On-Site Design and Operations
Particular attention must be paid to the potential for on-site traffic operations to affect the safe and efficient operation of the adjacent roads and the ability of the site to support the City of Ottawa’s transportation policy objectives. Focus will be on identifying:
• An evaluation of proposed on-site circulation and provision for pedestrian and cycling movements, including pedestrian movements to and from transit stops (clear and direct pedestrian and cycling pathways must be provided, including connections to existing facilities);
• Potential for conflict/ spill-back from on-site intersections and parking aisles/ stalls to driveway intersections with the City’s road network; and
• Location of truck access and loading/ unloading facilities.
• The City recognizes that there are a number of legislative and By-law requirements and physical site constraints that are considered in the development of a Site Plan (e.g., Building Code, Zoning By-law, etc). The transportation objectives for on-site circulation and access may be superseded by other governing regulations.
C2.4 Community Concerns
C2.4.1 Community Transportation Impacts
The TIS report will review the transportation network in the vicinity of the proposed development and identify potential neighbourhood infiltration routes. Focusing on these routes in the study area, the report will identify site-related traffic impacts on potentially affected neighbourhood streets during both the commuter peak and the projected site peak and an appropriate mitigation strategy, where one is required.
C2.4.2 Parking Impacts
For developments that generate significant auto parking demand the TIS report will review the site- generated parking demand and will demonstrate an appropriate parking strategy for the development.
C2.5 Transportation Demand Management
A Transportation Demand Management (TDM) plan must be prepared for the proposed development, identifying links to City’s TDM initiatives and mechanisms for integrating the proposed development into the existing services and programs. The City’s TDM Section, within the Public Works and Services Department, is available to assist in developing a TDM plan.
C3 Documentation and Reporting
The structure and format of the Transportation Brief should follow the guidelines outlined in this document, as applicable. The following is a suggested report structure:
Report Context
Description of the development (include all of the following that are known at the time of the application):
• Municipal address;
• Location relative to major elements of the existing transportation system (e.g., the site is located in the southwest quadrant of the intersection of Main Street/ First Street, 600 metres from the Maple Street Rapid Transit Station);
• Existing land uses or permitted use provisions in the Official Plan, Zoning By-law, etc.;
• Proposed land uses and relevant planning regulations to be used in the analysis;
• Proposed development size (building size, number of residential units, etc.) and location on site;
• Estimated date of occupancy;
• Planned phasing of development;
• Proposed number of parking spaces (not relevant for Registration of Plans of Subdivision); and
• Proposed access points and type of access (full turns, right-in/ right-out, turning restrictions, etc.).
• Study area;
• Time periods and phasing; and
• Horizon years (include reference to phased development).
The TB must include a key plan that shows the general location of the development in relation to the surrounding area. The TB must also provide a draft site plan or development concept of a suitable scale that shows the general location of the development and the proposed access locations. If the proposed development/ redevelopment is to be constructed in phases, a description must be provided for each phase, identifying the proposed timing of implementation.
Existing Conditions
• Existing roads and ramps in the study area, including jurisdiction, classification, number of lanes, and posted speed limit;
• Existing intersections, indicating type of control, lane configurations, turning restrictions, and any other relevant data (e.g., extraordinary lane widths, grades, etc.);
• Existing access points to adjacent developments (both sides of all roads bordering the site);
• Existing transit system, including stations and stops;
• Existing on- and off-road bicycle facilities and pedestrian sidewalks and pathway networks;
• Existing system operations (V/C, LOS); and
• Major trip generators/ attractors within the Study Area should be indicated.
The TB report must include figures documenting the existing travel demands by. A photographic inventory of the transportation network elements in the vicinity of the proposed access points would be beneficial to staff in their review of the Consultant’s report.
Demand Forecasting
• Trip generation forecasts
Impact Analysis
• Qualitative assessment of impacts on capacity; non-auto modes; on-site circulation; community Mitigation Measures and Site Design Characteristics
The TB must identify all mitigation measures required to offset network impacts from the development.
The TB must also identify key site design features required to implement the Official Plan and Transportation Master Plan policies regarding site development.
The TB must include all of the following, where they are required by the subject development:
• Location and timing of proposed changes to existing traffic controls at intersections (e.g., new traffic signals, Stop signs, etc.);
• Mitigation measures required to offset impacts on the surface and Rapid Transit networks;
• New or modified elements of the bicycle and pedestrian networks;
• Community impact mitigation measures; and
• Proposed TDM features or programs to support the site development.
Appendix D - Transportation Impact Study Analysis Methods and Documentation Requirements
D1 Introduction
The Transportation Impact Studies - Analysis Methods and Documentation Requirements appendix establishes the accepted methodologies for analyzing development impacts, determining required mitigation measures and documenting the results for TIA related transportation impact studies.
Transportation Impact Studies (TIS) focus on determining the specific infrastructure and programs needed to mitigate the impact of the proposed development on the local transportation network and establishing the site design features needed to support system-wide transportation objectives. Where geometric modifications are, or a change in the function of the existing road is required, delegated authority will be required to approve the road work on City Council’s behalf. Appendix F - Roadway Modification Approval (RMA) Report Element Formats identifies the RMA requirements to be included in the analysis, design and documentation of the TIS report.
The methodologies identified in this section should be read in conjunction with the direction and
understanding of the base conditions of the TIA as identified in the TIA Guidelines report and Appendix A.
D2 Analysis Methods
D2.1 System Congestion/Capacity
D2.1.1 Intersection Capacity
An operational evaluation of signalized and unsignalized intersections that will be affected by site generated traffic volumes during any or all of the relevant time periods and scenarios is required.
Summaries are to be provided in tabular format clearly identifying intersection performance under
existing, future background, and total future traffic conditions. Detailed output from analysis software is to be provided in an appendix to the report and copies of the electronic files should be provided on CD.
Appendix E outlines parameters to be used in operational analysis of signalized intersections.
All volume to capacity (V/C) calculations relating to future conditions should be determined using signal timing optimized for the volume conditions being studied. The V/C ratio for an intersection is defined as the sum of equivalent volumes for all critical movements divided by the sum of capacities for all critical movements assuming that the V/C ratios for critical movements can be equalized. In cases where minimum pedestrian phase times prevent equalizing the level of service for critical movements, then the V/C ratio for the most heavily saturated critical movement should be considered as the V/C ratio for the intersection. Adjustment for the impact of pedestrian activated control is permitted provided detailed supporting analysis including projected pedestrian volumes is provided and discussed in advance with traffic engineering staff.
The Consultant must undertake at least one hour of observations during peak traffic conditions to verify that the traffic volumes through the intersections reflect existing demands and to identify unusual
