Traffic Impact Studies in Durham Region

These guidelines are relevant for applications within Ajax, Brock, Clarington, Oshawa, Pickering, Scugog, Uxbridge and Whitby, however each municipality may have guidelines that supplement the below.

Understanding the Transportation Requirements for Your Development

A Traffic Impact Study (TIS) evaluates how a proposed development will affect the surrounding transportation network and identifies the improvements needed to accommodate future travel demand. Using the Municipality of Clarington as an example, the assessment considers road and intersection capacity, site access, traffic safety, parking, public transit, cycling and pedestrian facilities.

A TIS supports the development approval process by identifying transportation constraints, determining appropriate mitigation measures and establishing the timing and potential financial responsibility for required improvements. The scope depends on the proposed development, its location and anticipated transportation impacts.

What Does the TIS Process Involve?

1. Confirming the Study Scope

The process begins with pre-consultation with Clarington’s Engineering/Building Services Department to determine whether a full Traffic Impact Study or a shorter, opinion-based Traffic Impact Statement is appropriate. The consultation establishes the study area, analysis periods, forecast years, data requirements and acceptable technical methods. Durham Region, the Ministry of Transportation of Ontario (MTO) and transit agencies may also need to be consulted, depending on the infrastructure affected.

2. Assessing Existing Conditions

The consultant reviews road classifications, intersections, traffic controls, transit routes, cycling facilities, sidewalks and adjacent land uses. Traffic volumes, turning movements, vehicle classifications, collision records and signal timing are collected or obtained from the relevant authorities. Clarington’s guidelines call for new traffic counts where available data is more than one year old or does not cover the required location, helping ensure that the analysis reflects current conditions.

3. Forecasting Future Traffic Demand

The study estimates the trips generated by the development and distributes them across the surrounding road network. Forecasts incorporate background traffic growth, approved but unbuilt developments and planned road improvements. Typical assessment horizons include opening day, generally within one to five years of existing conditions, and five or ten years after full build-out. Additional scenarios may be required for phased developments.

4. Evaluating Operations, Safety and Access

Existing and future conditions are assessed to identify capacity constraints, delays, vehicle queues and deficient turning movements. The analysis also examines access spacing, sight distance, auxiliary turning lanes, potential conflicts with pedestrians and cyclists, transit operations, truck movements and traffic infiltration into surrounding neighbourhoods.

5. Developing Mitigation Measures and Submitting the Report

Where deficiencies are identified, the consultant recommends measures such as intersection improvements, turning lanes, traffic controls, access modifications, pedestrian and cycling connections, transit-related improvements or parking management strategies. The report documents the findings, recommended improvements, implementation timing and, where required, preliminary cost estimates. Qualified transportation professionals must prepare and sign the report in accordance with Clarington’s submission requirements.

What Makes Clarington’s Requirements Distinctive?

A flexible, impact-based scope: Clarington can require anything from a brief Traffic Impact Statement to a comprehensive TIS, depending on the development’s anticipated effects on the transportation network. The guidelines do not rely on a single universal trip-generation threshold.

Explicit operational performance targets: The guidelines generally target Level of Service (LOS) D or better at urban intersections, with individual turning movements at LOS E or better. Rural free-flow road sections are expected to achieve LOS C or better. Screenline analysis is also used to assess road-network capacity, with additional capacity improvements identified where the volume-to-capacity ratio exceeds 0.90.

Detailed access and sight-distance reviews: Access points are assessed for capacity, queue storage, safe spacing and sightlines. The guidelines favour locating access on minor roads where feasible, aligning accesses with existing intersections where possible, and justifying additional access points based on traffic demand rather than design preference.

Neighbourhood, parking and site-circulation impacts: The study may examine traffic infiltration onto local residential streets, spillover parking, drive-through queues, accessible parking and pedestrian routes, loading areas, emergency vehicle circulation and fire routes. Vehicle turning templates may be required to demonstrate that larger vehicles can move through the site safely.

Consideration of non-automobile travel: Applicants must assess provisions for transit, cycling and walking, including connections to surrounding facilities, transit-stop access, potential impacts on transit operations and gaps in pedestrian or cycling networks. A Travel Options Plan outlining Transportation Demand Management (TDM) measures may be required for selected developments.

Coordination across transportation authorities: Responsibilities are divided between Clarington, Durham Region, MTO and transit providers. Clarington manages local and collector roads and some arterial roads, while Durham Region is responsible for Regional roads and the traffic signal system. Early coordination helps determine the applicable design standards, review requirements and responsibilities for improvements.

Plan Ahead for Development Approval

Early consultation with Clarington and the relevant road authorities helps establish the right study scope, identify access and infrastructure constraints, and clarify potential mitigation obligations. Incorporating traffic operations, site circulation, parking and multimodal connections into the initial design can help reduce revisions and support a more efficient development review process.

Reference: Municipality of Clarington — Traffic Impact Study Guidelines. The linked document is Version 2, dated January 2015. Requirements should be confirmed with Clarington and Durham Region, as applicable, before commencing a study.

How Do TIS Requirements Differ Across Durham Region?

Although Clarington provides a useful example of the Traffic Impact Study process, developers should also account for the individual planning policies and submission requirements of Ajax, Oshawa, Pickering and Whitby. The underlying Durham Region guidelines provide a common framework, but the applicable municipality, development type and location can influence the scope of the required transportation assessment.

Ajax: Transit Impacts, Parking Utilization and Traffic Management

Compared with Clarington, Ajax’s Official Plan explicitly identifies several distinct transportation studies that may be required in support of development applications.

Traffic and Transit Impact Studies: Ajax identifies developments near local, collector or arterial roads that may affect the transportation network as potential triggers for an assessment. Specific examples include proposals expected to generate more than 100 two-way vehicle trips during peak hours, developments creating access issues, or proposals affecting an arterial road or intersection. The Town may also require a study in other site-specific circumstances.

Parking Utilization Studies: Where a proposal includes substantially fewer or significantly more parking spaces than required by the Town’s Zoning By-law, Ajax may require a study comparing expected parking demand with the proposed supply. Recommendations may include shared parking between uses or appropriate off-site parking arrangements.

Traffic Management Plans: Draft Plans of Subdivision must be accompanied by a Traffic Management Plan addressing matters such as driveway locations near intersections, sight triangles, road geometry, sidewalk placement and traffic-calming measures. The objective is to manage neighbourhood traffic impacts while supporting pedestrian, cycling and transit-friendly streets.

What developers should plan for: In Ajax, the transportation submission may need to address parking demand, transit impacts and subdivision road design separately from the conventional traffic-capacity analysis.

Reference: Town of Ajax — Official Plan.

Oshawa: Retail Development and Land-Use-Specific Transportation Requirements

Oshawa uses the broader Durham Region transportation-review framework, supplemented by specific Official Plan policies for certain development types. One notable distinction is the explicit requirement for transportation studies associated with particular retail land-use designations.

Planned Commercial Centres: An application to amend the Official Plan to designate a Planned Commercial Centre exceeding 1,400 m² of gross leasable floor area for retailing goods and services must include a Transportation Impact Study. The study must assess the development’s effects on adjacent roads and identify design measures to resolve potential transportation problems. The City may also request a study for smaller proposals.

Major retail development: Certain major retail uses proposed on designated industrial lands are subject to additional policy requirements, including a Transportation Impact Study addressing adjacent roads and a separate Retail Impact Study where applicable. These assessments consider transportation operations and the broader implications of the proposed commercial development.

Engineering and access design: The City’s engineering design requirements also inform the design of intersections, turning lanes, storage lengths and sight distances, with traffic volumes and TIS recommendations considered in the design process.

What developers should plan for: Retail and commercial projects in Oshawa should confirm whether land-use-specific policies trigger a TIS or a separate Retail Impact Study, in addition to any requirements arising from the general Durham Region framework.

Reference: City of Oshawa — Official Plan and Engineering Design Criteria Manual.

Pickering: Traffic Sensitivity Analysis and Subdivision-Wide Planning

Pickering’s Official Plan includes a distinctive requirement for a Traffic Sensitivity Analysis in support of Draft Plans of Subdivision. This assessment goes beyond examining the immediate traffic generated by a single development access.

Neighbourhood-wide capacity assessment: The analysis evaluates intersection and road capacity, level of service and sensitivity to changing travel demand across the neighbourhood in which the subdivision is located. It must demonstrate that the transportation network can accommodate anticipated demand while supporting the community-design objectives of the Official Plan.

Coordinated traffic and transportation planning: For certain larger subdivision and area-planning projects, additional requirements may include an Intersection Control Plan, traffic-signal implementation program, Traffic Management Implementation Plan, transportation planning exercise, Transportation Demand Management Plan and Parking Management Plan. These additional deliverables are project-specific rather than automatic requirements for every development.

Infrastructure timing and implementation: The review may extend to the coordination of new road connections, intersection controls, traffic signals and mitigation measures with the subdivision’s development phases. The applicable study scope depends on the site and the planning policies governing the area.

What developers should plan for: Subdivision proposals in Pickering may require a broader assessment of neighbourhood capacity, travel-demand sensitivity and infrastructure implementation, rather than a study limited to nearby intersections.

Reference: City of Pickering — Official Plan, Edition 9.

Whitby: A Broader Suite of Supporting Transportation Studies

Whitby’s current Official Plan identifies a range of transportation-related reports and plans that may be required to support a complete development application. The scope is determined through pre-consultation and should be proportionate to the scale and complexity of the proposal.

Additional study requirements: In addition to a Traffic Impact Study, the Town may require a Transit Study, on-site Traffic Management Plan, Parking Study, Parking Management Plan, Haul Route Plan, Active Transportation Plan or Transportation Demand Management Strategy. These are potential requirements, not mandatory studies for every application.

Area-specific road-network planning: Whitby’s Official Plan includes specialized requirements for particular growth areas. For example, development applications within the southwest quadrant of Baldwin Street and Winchester Road in Downtown Brooklin must include a TIS addressing the proposed collector and local road network, connections to the surrounding arterial network, and intersection locations, configurations and spacing. These matters must satisfy the relevant provincial and municipal authorities, in consultation with Durham Region.

Transit-supportive development and parking: In areas such as Port Whitby, the Official Plan supports development that encourages transit use. Under the applicable policies, parking reductions may be considered where a Transportation Demand Management Plan and implementation strategy demonstrate that vehicle demand can be reduced.

What developers should plan for: Whitby applicants should confirm the complete study requirements during pre-consultation and determine whether separate transit, parking, active transportation, haul-route or TDM submissions are necessary.

Reference: Town of Whitby — Official Plan, Office Consolidation, April 2026 and Design Criteria and Engineering Standards, 2025.

A Common Starting Point, With Municipality-Specific Requirements

For developments across Durham Region, early consultation with the applicable local municipality and Durham Region is essential. Confirm which authority reviews each road or access, whether the development triggers a full TIS or a more focused assessment, and whether separate reports are needed for transit, parking, traffic management or transportation demand management.

Identifying these requirements early allows developers to coordinate their site design, technical studies and infrastructure obligations before submitting a formal development application.

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