Introduction and Project Background

A Transportation Master Plan (2010) was developed as part of the Downsview Area Secondary Plan (DASP) to assess and identify the transportation infrastructure requirements necessary to support growth and development within the DASP (TMP, 2010), fulfilling Phase 1 and 2 requirements of the MCEA process. In 2014, the City of Toronto (the City) initiated a Schedule C Municipal Class Environmental Assessment (MCEA) study for selected major roads within the Downsview Area Secondary Plan (DASP), located in the City of Toronto, Ontario. The study was carried out in accordance with the Municipal Engineers Association’s (MEA) Five Phase MCEA process (October 2000, as amended in 2007, 2011 and 2015) which is approved under the Ontario Environmental Assessment Act (Ontario EA Act). AECOM Canada Limited (AECOM) was retained by the City of Toronto to undertake Phases 3 and 4 of the MCEA process and fulfil the EA requirements for Schedule C projects.

Study Area

The Study Area for the Project includes a 1.2 km long westerly extension of Transit Road across Sheppard Avenue West to Keele Street; a 2.3 km long northerly extension of Transit Road, which provides a connection to Chesswood Drive / Sheppard Avenue West; and completion of the planning for Perimeter Road to run south from the future east-west section of Transit Road, connecting with Keele Street via Downsview Park Boulevard, which is being built as part of the Stanley Greene Neighbourhood.

The main land uses within the Study Area include recreation facilities (indoor / outdoor facilities including parks and open space), stand-alone commercial / retail features, educational / childcare facilities, Downsview Airport and government buildings. There are a number of residential areas near the Study Area which include the neighbourhoods of Bathurst Manor, Clanton Park, Downsview-Roding CFB, Glenfield-Jane Heights, York University Heights and the recently occupied Stanley Greene neighbourhood. The dominant property owners within the Study Area include Canada Lands Company (CLC), Bombardier Aerospace, City of Toronto, the Department of National Defence (DND), Metrolinx / GO Transit and Build Toronto.

Class EA Phase 1 and 2 Overview

Downsview Area Secondary Plan

The current DASP is included in Part 7 of Chapter 6 of the City of Toronto Official Plan (OP). The DASP area is approximately 530 hectares (ha) (1,309 acres) in area and encompasses lands generally bound by Wilson Avenue between Keele Street and Wilson Heights Boulevard, south of Sheppard Avenue West.

A review and update of the DASP was conducted by City Staff in May 2008. The review and update was an opportunity for the City to reassess the existing 1999 Secondary Plan in the context of the City’s planning goals and objectives and to ensure that the planning policies for the area are current and appropriate to guide future development.

The outcome of this review was the City Planning Final Report, completed on March 4, 2011, which recommended that Council replace the 1999 Downsview Area Secondary Plan with an updated Secondary Plan. The plan review emphasized the creation of a major national urban park and mixed urban land use which would be supported by a comprehensive transportation network, and intensified land use near the new TTC and Metrolinx / GO Transit Sheppard West transit terminal.

Transportation Master Plan

As part of the DASP review, a TMP update (MCEA Phase 1 and 2) was undertaken to assess and identify the transportation infrastructure requirements necessary to support current and future growth and development within the DASP area. An overview of the results of Phases 1 and 2 is provided below.

Phase 1 – Problem and Opportunity Statement

The Problem and Opportunity Statement, from the TMP is as follows:

The Spadina Subway Extension, a new TTC subway station and GO Transit station, along with a renewed development vision proposed by Parc Downsview Park Inc., have created an opportunity to reconsider the approved Transportation Master Plan. In support of an updated Downsview Area Secondary Plan, the Transportation Master Plan will continue to respond to investment in transit and the incorporation of infrastructure and policies that are more transit-supportive.

There is a lack of road network connectivity throughout the Secondary Plan due to the physical constraints posed by the CN (now Metrolinx) railway line, Bombardier runway and Wilson railway yard. As a result, the existing area road network and surface transit routes are operating close to their capacity.

All of these elements identify that there is a basic need and opportunity to develop sustainable transportation infrastructure to serve the long term development aspirations of the Downsview Area Secondary Plan.


Phase 2 – Alternative Solutions

Phase 2 of the MCEA process is focused on identifying and assessing alternative solutions and selecting a preferred solution.

Specifically, major street elements 1, 2, and 4 of the recommended street network presented in the TMP, included:

  1. A north-south Transit Road Extension from Allen Road through the Chesswood district to Sheppard Avenue West (North-South Transit Road).
  2. An east-west road from Chesswood district to Keele Street provides connectivity to the N-S Transit Road Extension and eventually to Allen Road (East-West Transit Road).
  3. The east-west perimeter road at the south end of the Plan provides access to the Sports/Cultural Commons Centre and defines the southern limit of the National Urban Park district (Perimeter Road).

It was confirmed through additional traffic modelling and professional engineering judgement that the preferred street network identified in the 2010 TMP is the best way to solve the existing problem. This project therefore relies on the road alignments shown as part of the TMP’s recommended street network and focuses on identifying and assessing alternative design concepts for North-South Transit Road, East-West Transit Road, and Perimeter Road as part of Phase 3 of the MCEA process.


Alternative Design Concepts

The alternative design concepts developed for this project were based on the DASP – TMP’s recommended street network. Specifically, alternative design concepts were developed for:

  • East-West Transit Road
  • North-South Transit Road
  • Perimeter Road

Alternative design concepts for each street segment were evaluated against a set of criteria. For a given criterion, the preferred alternative for the street segment under evaluation was identified. The evaluation considered feedback from stakeholders (including the Technical Advisory Committee (TAC)) and was completed using professional judgement and the results of studies conducted during the planning process. Quantitative results from the studies were also used to substantiate the evaluation rationale where applicable.

Following the evaluation of alternative design concepts, Alternative 1 was identified as the preferred alternative for each street segment. The rationale for the selection of Alternative 1 for each street segment is summarized below:

  • East-West Transit Road: Maximizes the developable area of the William Baker District by locating the ROW above the subway tunnel (to the extent possible); and, Creates larger development blocks.
  • North-South Transit Road: Best accommodates future property development; Provides the largest area available for the build-out of the Allen District Concept Plan; More compatible with the plan for the future park to the north of the proposed alignment; and, Allows for a larger area for park use.
  • Perimeter Road: Best accommodates future development, particularly Bombardier’s aero-structures plans; and, Does not impact Bombardier property within this area and is not expected to impact operations associated with their paint and welding yard in the vicinity of Perimeter Road.

Preferred Design

The preferred design for the Project considered transportation facilities for all street users (motorists, transit, cyclists, pedestrians, goods movement) and potential impacts to the community, natural environment, cultural environment, safety, aesthetics, property and access requirements, and capital construction and maintenance costs. The preferred design for the Project was selected, developed, and refined through consultation with agencies, stakeholders and the public.

Street Design

The preferred North-South Transit Road alignment extends from the existing terminus of Transit Road in the south to Chesswood Drive in the north. The southern portion of North-South Transit Road has a 27.0 m ROW width and north of Link 5, North-South Transit Road transitions to a 22.8 m ROW width. The connection to existing Transit Road cycling facilities, along with future pedestrian and cycling connections to Downsview Station will be examined during detailed design. A pedestrian and cycling connection to Wilson Subway Station will be examined during detailed design or in a separate study.

The preferred East-West Transit Road alignment extends between Keele Street in the west and North-South Transit Road in the east. East-West Transit Road has a 27.0 m ROW. The ROW at the railway underpass widens to 32.0 m to accommodate the proposed structure. Future pedestrian and cycling connections to the Keele / Dovehouse pedestrian and cycling facilities will be examined during detailed design. The connection to existing Transit Road cycling facilities, along with future pedestrian and cycling connections to Downsview Station will be examined during detailed design as well.

The preferred Perimeter Road alignment extends from East-West Transit Road in the north to Downsview Park Boulevard in the west. Perimeter Road has a 27.0 m ROW width. The Perimeter Road cross-section is designed to allow for the road to be widened to four lanes in the future if required.


There are two structures associated with the preferred street network design: the underpass on East-West Transit Road and the overpass on Perimeter Road. The underpass consists of two cast-in-place concrete box structures containing a concrete ballasted top, abutment and middle reinforced concrete walls and reinforced concrete footing slabs. Retaining walls are required east and west of the new bridge. The bottom of the footings is approximately 9 m below the existing track elevation and approximately 2 m below existing grades. The design of the underpass provides 5 m of vertical clearance.

The overpass consists of a 25 m single span structure comprised of a reinforced concrete deck on precast girders while the abutments substructure is comprised of cast-in-place reinforced caissons with concrete cap walls and false Retained Soil Systems (RSS) abutments and retaining walls east and west of the new bridge. The bottom of the footings is approximately 2 m below existing grades. The design of the overpass provides 7 m of vertical clearance for the rail corridor. Both structures are sufficiently wide to accommodate a future third track for Metrolinx as part of the GO Barrie Line.

Drainage and Stormwater Management

For the internal drainage within the street network ROWs, the storm sewers will be sized for:

  • The 100-year flow for areas with no major system outlet (i.e., the Chesswood storm trunk sewer to the north, and the Wilson Heights Boulevard storm outlet to the southeast), and to prevent as much flow as possible from draining to the sag location at the proposed grade separation).
  • The 2-year flow elsewhere.

A portion of the road draining to the grade separation on East-West Transit Road cannot be serviced with a gravity storm sewer due to both the elevation of the existing storm outlet (storm sewer crossing Sheppard Avenue West to the 1650 mm Chesswood trunk storm sewer) and the elevation of the newly constructed subway box for the Toronto-York Spadina Subway Extension. As a result, a pumping station with a pumping rate of 0.7 m3/s is required adjacent to the underpass.

Stormwater management requirements include peak flow control, water quality control, erosion control, and water balance. It is required to control storm peak flow to each of these outlets. In general, there are three options for storage of this volume at each of the storm outlets:

  • Storage in oversized pipes just prior to the outlet to the receiving storm sewer;
  • Storage in surface stormwater management (SWM) ponds just prior to the outlet; or
  • Distributed storage throughout the length of the ROW, integrated with low impact development (LID) features to address quality control, erosion control, and water balance.

The water quality control requirements, as per the City Wet Weather Flow Management Master Plans, are to provide enhanced water quality control for the new road area. Water balance requirements are to retain 50 % of the annual runoff volume on site (or, equivalently, retain the first 5 mm of each rainfall on site with no discharge Options for implementing these requirements are outlined below:

  • Option 1 Oversized Pipes, Oil Grit Separators with LID,  5 mm Retention LID
  • Option 2 End of Pipe Pond,  5 mm Retention LID
  • Option 3 LID with Distributed Storage along Road Corrido

Utilities and Street Lighting

Full illumination is proposed for the preferred street network. The street illumination design will be based on City of Toronto standards and will be confirmed during detailed design. Elements such as the street profile and active transportation requirements will be considered in the illumination design. Approximate pole locations and spacing have been identified in Appendix H Functional Street Network Design.

Property Requirements

Property requirements for the Project are outlined below.

  • North-South Transit Road – Drawing No. 25
    • Approximate Total Property Acquisition (m2): 70,600
    • Approximate Easement (m2): 0
  • East-West Transit Road – Drawing No. 26
    • Approximate Total Property Acquisition (m2): 33,200
    • Approximate Easement (m2): 6,750
  • Perimeter Road – Drawing No. 27
    • Approximate Total Property Acquisition (m2): 71,600
    • Approximate Easement (m2): 1,065

Property requirements are approximate and are based on functional design and are subject to confirmation during the detailed design phase of the Project.

Preliminary Cost Estimate

The preliminary construction cost of the preferred street network design at the functional (10 %) design stage is estimated at $197,285,708.

The estimated cost breakdown for each road alignment is as follows:

  • East-West Transit Road $84 M
  • North-South Transit Road $38 M
  • Perimeter Road $54 M


North-South Transit Road and East-West Transit Road are expected to proceed as part of the first stage of construction. North-South Transit Road must be built first, as it provides the southern connection for East-West Transit Road. Staging is dependent partially on the timing of adjacent development, including the Allen Road District (for North-South Transit Road) and the William Baker District (for East-West Transit Road). Perimeter Road is anticipated to be built after the other two roads, once a need is determined from a traffic perspective.

Environmental Effects and Mitigation

Anticipated impacts to the transportation system, natural environment, socio-economic environment, archaeology and cultural and contamination together with proposed mitigation measures were identified to address the implementation of the preferred design.

In general, impacts associated with the Project are minor in nature and can be mitigated. Further information on environmental effects and mitigation can be found in Section 6 of this report.

Future Commitments

Timing of the implementation of the preferred street network is to be confirmed during detailed design. Section 7 of this report identifies specific items to be reviewed and confirmed during detailed design. Table 7-1 provides the complete list of future commitments.

Consultation and Communication Process

The consultation and communication process and activities used throughout this MCEA Study are detailed the City of Toronto Public Consultation Report (Appendix L). The report also includes correspondence records and meeting materials.