Transportation Impact Assessments (TIA) in Ottawa

Understanding the Transportation Requirements for Your Development

A Transportation Impact Assessment (TIA) evaluates how a proposed development will affect Ottawa’s existing and future transportation network. It identifies the improvements required to accommodate new travel demand while supporting the City’s objectives for safe, accessible and sustainable transportation.

Unlike a traditional traffic study focused primarily on vehicle capacity, Ottawa’s TIA process considers the development’s design, site access, intersection operations, transit, cycling, pedestrian connectivity, parking and opportunities to reduce automobile dependence. The study helps determine whether a development can be integrated into the surrounding network and identifies on-site and off-site improvements that may be required as part of development approval.

What Does the TIA Process Involve?

1. Screening and Scoping

The process begins with a TIA Screening Form to determine whether a detailed assessment is required. Ottawa generally triggers a TIA when a development generates 60 or more person-trips per hour, is located in a designated transportation or transit-oriented area, or presents potential safety concerns. Smaller developments may still require a focused design review.

The next stage establishes the study area, analysis periods, forecast assumptions and applicable assessment modules in consultation with City staff. This ensures the study is proportionate to the development’s anticipated impacts.

2. Forecasting Travel Demand

The consultant estimates the trips generated by the development, including the expected distribution between automobile, transit, walking and cycling. Forecasts also account for background traffic growth, surrounding developments and planned transportation infrastructure. The analysis considers future conditions with and without the proposed development to identify the project’s incremental impacts.

3. Assessing Development Design and Network Performance

Ottawa’s TIA framework has two central components: Design Review and Network Impact. Design Review examines whether the site layout, access points, circulation and connections to surrounding streets support the City’s transportation objectives. Network Impact evaluates how development-generated trips affect the performance of roads, intersections and other relevant transportation facilities.

Depending on the agreed scope, the analysis may include intersection operations, access design, transit capacity and priority, pedestrian and cycling facilities, traffic calming, and parking supply.

4. Developing Mitigation Measures

Where deficiencies are identified, the consultant evaluates solutions that address transportation impacts without compromising the needs of other road users. Measures may include intersection modifications, turning lanes, revised site access, pedestrian and cycling connections, transit-priority measures, parking adjustments and Transportation Demand Management initiatives.

5. Preparing the Final Submission

The final submission documents the screening and scoping, forecasts, analysis, recommended improvements and implementation strategy. Engineering and functional-design drawings may be required to support proposed road modifications. A monitoring plan may also be necessary where mitigation or changes in travel behaviour are to be implemented or evaluated over time.

What Makes Ottawa’s TIA Requirements Distinctive?

A structured screening system: Ottawa uses person-trip generation, location and safety triggers rather than relying exclusively on vehicle-trip thresholds. Developments generating fewer than 60 peak-hour person-trips may still require a design-focused assessment because of their location or access-related risks. Protected Major Transit Station Areas, Design Priority Areas, transit-oriented development areas and designated transit or cycling corridors are important screening considerations.

Separate design and network assessments: The process examines both the layout of the development and its broader transportation impacts. For example, a site may need a design review even where a full intersection-capacity assessment is not warranted. Under the 2023 revisions, detailed intersection-design modules generally apply when site-generated automobile trips exceed 75 per hour, while transit-route capacity analysis is triggered when site-generated transit trips exceed 75. City staff retain discretion over the final scope.

A strong multimodal and Complete Streets focus: The assessment considers how development design influences travel choices and safety for pedestrians, cyclists, transit users and motorists. Site layouts and proposed street improvements should connect to the wider transportation network and support Ottawa’s policies for sustainable transportation and multimodal level of service.

Transportation Demand Management requirements: A TDM assessment is required for developments generating more than 60 person-trips. Applicants use the City’s TDM Measures Checklist to identify appropriate initiatives and may need a TDM-supportive development design and infrastructure assessment. Larger or more complex proposals may require additional analysis and an implementation plan covering responsibilities, timing, performance targets and monitoring.

Neighbourhood traffic-calming considerations: Certain developments may require an assessment of traffic infiltration onto local and collector streets between the site and nearby arterial roads. This is particularly relevant where development-generated traffic could affect residential streets and sensitive land uses such as schools, parks, childcare centres and community facilities.

A streamlined review process: Ottawa’s June 2023 guideline update moved forecasting tasks into scoping and analysis, eliminating the standalone forecasting report and one City check-in. The changes also removed the separate spillover-parking analysis module and refined the requirements for intersection analysis, helping reduce unnecessary work for some lower-impact developments.

Plan Ahead for Development Approval

Early consultation with Ottawa’s development review and transportation staff helps establish the required assessment scope, identify potential site-design constraints and determine which supporting studies and mitigation measures will be needed. Integrating transportation considerations early can reduce redesign, clarify infrastructure obligations and support a more efficient development application review.

References: City of Ottawa — Transportation Impact Assessment Guidelines, including the 2017 guidelines and revisions effective June 2023; Engineering — Planning Application Submission Requirements. Requirements depend on the proposal and the scope confirmed with City staff.

Our team has in-depth expertise at conducting these assessments. Contact us today to find out how we can help with your project.