You have the site. You have the architect. You have the vision. But before the City of Toronto, Brampton, Mississauga, or any Ontario municipality will approve your development application, there is one document that almost always ends up on the critical path: the Traffic Impact Study (TIS).
A TIS is not just a regulatory hurdle — it is a planning tool that shapes your site access, parking layout, intersection improvements, and long-term operating costs.
In this guide, we explain exactly what a Traffic Impact Study is, when Ontario municipalities require one, what the study process looks like, and what developers in 2026 need to know about how the requirements are evolving.
What Is a Traffic Impact Study?
A Traffic Impact Study is a technical report that evaluates how a proposed development will affect traffic conditions on the surrounding road network. It answers three core questions that every municipality needs answered before approving a new development:
- How much additional traffic will this development generate?
- Where will that traffic go, and which intersections and roads will be most affected?
- What improvements — if any — are needed to keep the road network operating safely and efficiently?
The study uses traffic counts, accepted engineering models, and the Institute of Transportation Engineers (ITE) Trip Generation Manual to forecast the number of vehicle trips a development will add to the network during peak hours.
When Is a TIS Required in Ontario?
The threshold for requiring a Traffic Impact Study varies by municipality, but Ontario’s major cities generally follow similar guidelines. Most municipalities trigger the requirement based on the number of new vehicle trips generated during peak hours.
Beyond the trip generation threshold, a TIS is commonly required in the following specific situations:
| Situation | Why It Triggers a TIS |
| OPA / ZBA applications | Any Official Plan or Zoning By-law Amendment requires transportation impact analysis as part of the application package |
| Site plan approval | Required by most Ontario municipalities when a development generates 100+ new peak hour trips |
| New access to a regional road | Region of Peel, York Region, Durham, and others require a TIS for any new driveway onto a regional road |
| Drive-through restaurants | Always trigger a TIS due to queuing impacts on adjacent roads and intersections |
| Gas stations & convenience plazas | High-turnover, multi-use sites with complex access and queuing requirements |
| Industrial expansion | New loading docks, truck movements, or shift changes that significantly alter peak hour volumes |
| Mixed-use high-density development | Multiple uses combining residential, retail, and office traffic that compound at peak hours |
What Does the TIS Process Look Like?
A well-executed Traffic Impact Study follows a structured process. Here is what n Engineering’s team does on every TIS assignment:
Step 1: Scoping Meeting with the Municipality
Before any data is collected, we meet with the transportation planning department of the relevant municipality to agree on the study area, design years, peak hours, and the specific intersections and road segments to be analyzed. This scoping step aligns the study with what reviewers actually need to see.
Step 2: Traffic Data Collection
We conduct turning movement counts at key intersections within the study area during the agreed peak periods. For sites where existing count data is available from the City’s open data portal (as the City of Toronto published in early 2025), we may supplement field counts with this data — reducing cost and timeline.
Step 3: Trip Generation Forecasting
Using the ITE Trip Generation Manual and local calibration data, we calculate the number of new vehicle, pedestrian, cycling, and transit trips the proposed development will generate during each peak period. For mixed-use developments, internal trip capture and modal split adjustments are applied to reflect realistic conditions.
Step 4: Traffic Distribution and Assignment
The new trips are distributed to the surrounding road network based on existing travel patterns, origin-destination data, and the location of the site relative to major roads. This tells us which specific intersections and road segments will carry the most new traffic.
Step 5: Intersection Capacity Analysis
We model each study intersection using industry-standard software to determine how it will operate in the future — with and without the development. Level of Service (LOS) grades (A through F) are calculated for each intersection approach.
Step 6: Mitigation and Site Access Design
Based on the capacity analysis, we develop practical mitigation measures: turning lanes, traffic signal timing adjustments, new signals, driveway consolidations, or sight line improvements. We also optimize the site’s access configuration — driveway locations, throat widths, internal circulation — to minimize conflicts.
Step 7: Final Report and Agency Submission
We compile all findings, analysis, and recommendations into a professional report and submit it to the municipality and any other relevant agencies (MTO for provincial highways, regional transportation departments, etc.). We manage the back-and-forth with reviewers to address comments efficiently.
What’s Changing in 2026: Key Trends Developers Must Know
The Traffic Impact Study process in Ontario is not static. Here are the most important shifts happening in 2026 that affect what municipalities expect to see in your TIS:
Active transportation is now mandatory in scope
It is no longer acceptable to submit a TIS that only analyzes vehicle traffic. Toronto, Brampton, and Mississauga now require explicit analysis of pedestrian, cycling, and transit impacts as part of every TIS submission. This means evaluating pedestrian signal timing, cycling lane continuity, and transit stop proximity and accessibility.
Transit-oriented development (TOD) reduces parking requirements — and changes the TIS scope
With Ontario’s push for higher-density development near major transit stations, municipalities are accepting significantly reduced parking ratios for TOD projects. This changes the trip generation forecasting methodology: modal split assumptions must be justified with site-specific transit accessibility data, and often a Parking Justification Study must accompany the TIS.
The City of Toronto’s open transportation data is reshaping TIS timelines
The City of Toronto’s January 2025 release of motor vehicle and bike lane count data through its Open Data Portal is already affecting how TIS studies are scoped and costed. Engineers can now supplement or replace some manual field counts with City data, reducing data collection costs and speeding up the early stages of the study — a meaningful advantage for time-sensitive development applications.
Common Mistakes That Delay TIS Approvals
Based on our experience working across Toronto, Brampton, Mississauga, and the broader Ontario region, these are the mistakes that most commonly cause Traffic Impact Studies to be rejected or revised:
Starting the TIS after site design is finalized
The TIS should inform site design — especially driveway locations, turning radii, and sight lines. If you finalize the site plan first and discover access issues during TIS review, you’re looking at redesign costs and delays.
Underestimating the study area
Municipalities often require analysis of intersections further from the site than developers expect. Scoping meetings with the municipality before data collection begin are essential to avoid a rejected report.
Using outdated or unrepresentative traffic counts
Count data collected during school holidays, construction detours, or event periods will be rejected. Counts must represent typical weekday conditions, and many municipalities now specify which weeks are acceptable for data collection.
Missing the active transportation analysis
Submitting a vehicle-only analysis in 2026 will result in a revision request from virtually every Ontario municipality. Pedestrian, cycling, and transit impacts must be addressed.
Not coordinating with the Site Servicing Plan
Driveway locations, grades, and access geometry must be consistent between the TIS and the Site Servicing Plan. Inconsistencies are caught in technical review and trigger revision cycles.
How n Engineering Delivers Your Traffic Impact Study
n Engineering Inc. has prepared Traffic Impact Studies for a diverse range of development types across Ontario. Our team understands what Toronto, Brampton, Mississauga, and regional municipalities need to see — and how to get studies through review efficiently.
What sets our TIS work apart:
- We scope every study with the municipality before data collection begins — eliminating the most common cause of revision requests
- We integrate TIS findings directly into site design, so access geometry, driveway grades, and circulation are right from day one
- We coordinate traffic and stormwater analysis in-house, ensuring full consistency between the TIS and the Site Servicing Plan
- We manage all agency correspondence, from initial submission through to final approval letter
- We have direct experience with Toronto, Peel Region, York Region, and Ontario Ministry of Transportation (MTO) submission requirements
Need a Traffic Impact Study in Ontario?
n Engineering Inc. provides Traffic Impact Studies, Parking Justification Studies, Site Servicing Plans, Stormwater Management Reports, and the full range of civil and traffic engineering services required for development approvals across Toronto, Brampton, Mississauga, and Ontario. Contact us to discuss your project and timelines.
📞 416.256.9741 ✉️ info@nengineering.com 🌐 www.nengineering.com