Traffic Impact Studies in London

Understanding the Transportation Requirements for Your Development

A Transportation Impact Assessment (TIA) evaluates how a proposed development will affect the surrounding transportation network and identifies improvements required to accommodate future travel demand. In London, Ontario, the assessment considers traffic volumes, intersection capacity, site access, vehicle circulation, transit services, pedestrian and cycling facilities, and opportunities to reduce automobile dependence.

A TIA may be required to support planning applications such as Official Plan Amendments, Zoning By-law Amendments, Plans of Subdivision and Site Plan applications, particularly where a major development may affect the safety, efficiency or capacity of surrounding streets. The required scope depends on the proposed development, its location, anticipated travel demand and existing transportation conditions.

What Does the TIA Process Involve?

1. Establishing the Study Scope

The process begins with consultation with City of London staff to determine the appropriate level of assessment, study area, analysis periods and future forecast years. Depending on the proposal and previous studies completed for the site or surrounding area, the assessment scope may be adjusted to focus on the transportation issues most relevant to the application.

2. Reviewing Existing Conditions

The consultant documents the surrounding road network, intersection configurations, traffic controls, transit routes, sidewalks, cycling infrastructure and existing site accesses. Traffic counts, turning movements, vehicle queues and intersection operations are reviewed to establish baseline conditions. Existing access restrictions and the City’s road classification and access management requirements are also considered.

3. Forecasting Future Traffic Demand

The assessment estimates development-generated trips and their distribution across the surrounding road network. Future background conditions account for traffic growth, approved or proposed developments and planned transportation infrastructure. The resulting forecasts are used to assess future background traffic and future total traffic, including the proposed development.

Weekday morning and afternoon peak periods are typically assessed, with additional periods—such as Saturday peaks for retail developments—considered where appropriate. A future horizon year is generally selected at five years after full development build-out, with other scenarios included where phasing or local conditions warrant.

4. Evaluating Traffic Operations and Site Access

The consultant assesses intersection capacity, delays, volume-to-capacity ratios, turning movements and vehicle queues. The study also reviews driveway locations, access spacing, sight distances, turning-lane requirements, on-site circulation and potential conflicts involving pedestrians, cyclists and transit users.

5. Recommending Mitigation Measures

Where deficiencies are identified, the TIA recommends improvements to address operational and safety concerns. These may include turning lanes, intersection modifications, revised access arrangements, traffic-control measures, pedestrian and cycling connections, or site-circulation changes. Transportation Demand Management (TDM) measures appropriate to the development are also considered to encourage walking, cycling, transit use and carpooling.

6. Preparing and Submitting the Report

The final report documents the scope, traffic data, assumptions, forecasts, operational analysis, conclusions and recommended improvements. Supporting appendices generally include traffic counts, modelling results and other technical data. The study must be coordinated with City staff and relevant external agencies, where applicable, and prepared by qualified transportation professionals.

What Makes London’s TIA Requirements Distinctive?

Access Management Guidelines: London places particular emphasis on managing the number, location and design of driveways along major roads. The assessment considers driveway spacing, corner clearances, turning movements, sight distance and opportunities for shared access. Direct access to arterial roads may be discouraged where access through a collector road is feasible. These requirements can significantly influence site layout and the feasibility of proposed access points.

Defined operational performance criteria: London’s published TIA methodology identifies intersections and movements requiring further attention where volume-to-capacity ratios reach 0.90 or higher alongside Level of Service E or worse, or where projected 95th-percentile queues exceed available lane storage. These criteria help identify where additional analysis or mitigation may be necessary, subject to the approved study scope and applicable City requirements.

Future background and total traffic scenarios: The analysis separates future traffic without the proposed development from future conditions with the development included. This distinction helps determine the development’s incremental impact, account for other planned growth and identify improvements that may be needed as the area develops.

Transportation Demand Management and active transportation: The study considers appropriate measures to reduce reliance on single-occupant vehicles, alongside pedestrian and cycling connectivity, transit access and site circulation. Recommendations should respond to the development’s context and opportunities to support more sustainable travel choices.

Coordination with transit and other authorities: Developments affecting transit corridors, bus-stop access, arterial roads or provincial highways may require coordination with London Transit Commission, the Ministry of Transportation of Ontario or other relevant agencies. Early consultation helps clarify access requirements, technical expectations and approval responsibilities.

Accessible application submissions: The City requires planning justification reports and executive summaries for other submitted studies to be provided in an accessible format. Background reports and drawings intended for public viewing must also meet the applicable accessibility requirements. Non-compliant submissions can affect application completeness.

Plan Ahead for Development Approval

Early consultation with City of London planning and transportation staff helps establish the appropriate study scope, identify access constraints and determine potential infrastructure improvements before detailed site design is finalized. Integrating traffic operations, access management, parking and sustainable transportation measures early can help reduce redesign and support a more efficient development review process.

Reference: City of London — Planning and Development Applications and the City’s Transportation Impact Assessment Guidelines. The published guidelines are dated April 2012; confirm with City staff whether any subsequent technical modifications apply to the proposed development.

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