South Perimeter Highway Projects

The South Perimeter Highway is one of the most important economic corridors in Manitoba. As a part of the Trans Canada Highway, the South Perimeter Highway has a strategic role in connecting the provincial economy to world markets. The Perimeter Highway also provides communities with access to employment, education, services, and amenities.

St. Mary’s Road Interchange Project

The St. Mary’s Road interchange Project is a part of Manitoba Transportation and Infrastructure’s Winnipeg One Million Perimeter Freeway Initiative, which aims to support the international trade hub and accommodate the anticipated future population of Winnipeg and surrounding areas. This initiative includes a plan to upgrade the Perimeter Highway to a freeway standard as Winnipeg approaches reaching a population of one million. 

The intersection at St. Mary's Road (Provincial Road or PR 200) and the Perimeter Highway (Provincial Trunk Highway or PTH 100) was identified as a priority in the South Perimeter Highway Design Study, based on a set of evaluation criteria including current road capacity, traffic volumes, resultant level of service, existing safety issues and forecasted traffic growth. PR 200 is also an important link connecting the community of St. Adolphe to Winnipeg and surrounding towns in southern Manitoba.

The St. Mary’s Road Interchange Project will be completed in two phases: Interim and Ultimate. 

Interim Phase

The Interim phase of the project, which is currently being executed, is configured as a traditional diamond interchange with roundabouts at the two intersections and a bridge structure to cross PTH 100. St. Mary’s Road is realigned to the east to improve the crossing angle at the Perimeter Highway and increase the distance from the Red River.

The interchange is designed for four lanes of traffic and an active transportation pathway along the realignment. The Perimeter Highway will continue to be a four-lane roadway accommodating projected traffic volumes for approximately 30 years.

Ultimate Phase

As traffic volumes increase, based on forecasted growth in the Capital Region, the Ultimate design for the interchange will be implemented to increase to six traffic lanes on the Perimeter and two bridge overpasses on St. Mary’s Road.


June 2020 St. Mary’s Interchange Project Announced
October 2020-December 2021 Design-Build RFP Procurement Phase
January 2022 Contract awarded to Aecon Infrastructure Management Inc.
February 2022 Project Launch Meeting
March 2022 60% design, tree clearing
May 2022 Roadway construction starts, multiple phases
July 2022 100% design complete, Bridge structure construction starts
June 2024 Interchange open to traffic
November 2024 Construction fully completed

Project Plans

Project plans are shown at the 60% design stage and are subject to change as the design progresses to 100% design.

St. Mary's Interchange Project (PDF)


Traffic Information

Traffic will need to be re-routed occasionally throughout construction of the St. Mary’s Interchange. Lane closures and detour information will be updated here:

Manitoba 511

City of Winnipeg Lane Closures

Manitoba Infrastructure Projects Map

Contact Us

Major Projects Branch

South Perimeter Highway Safety Plan

A South Perimeter Highway Safety Plan was developed in 2018 with the intent to implement it over three years. The safety plan involves changes to access points in most locations, including the closing of median openings where intersections are controlled with stop signs. The project will also require investment in service roads.

Intersection improvements have been constructed at PTH 3 and at Symington Road to improve traffic operations. Construction will start on new service roads in 2020 to provide improved access to businesses along Aimes Road, Melnick Road, the Brady Road Landfill and the Oak Bluff Industrial Park. To further improve safety, additional access closures are under consideration for 2020.

The South Perimeter Highway Safety Plan can be viewed here: English (ZIP, 108.5 MB)

South Perimeter Highway Design Study

This involves the development of a longer-term plan for reconstructing PTH 100 to a freeway standard and providing for an ultimate six-lane roadway with three through lanes in each direction. A freeway standard means that there can be no at-grade crossings so that intersecting roadways and railways will be designed to be grade separated though interchanges and overpasses.

South Perimeter Design Study Final Report (PDF, 13 MB)

This publication is available in alternate formats upon request.

For alternate format requests, please contact Corporate Services Division, the Accessibility Coordinator at the email below:

Department of Infrastructure Accessibility Coordinator
1710 - 215 Garry Street
Winnipeg MB, R3C 3Z1

Phone: 204-945-4800

Design Drawings

South Perimeter Design Study Interim Stage Design Drawings

South Perimeter Design Study Ultimate Stage Design Drawings

St. Mary's Interchange Interim Solution Functional Design (PDF, 5.7 MB)


Noise Study

ITC South Perimeter Noise Study (PDF, 11.3 MB)