Abstract Manager

Project Overview & Design Evolution 

This presentation responds directly to TAC’s 2026 Conference theme under the ‘Confined Corridors and Intersections session, highlighting a corridor where spatial constraints demanded difficult tradeoffs. At Steeles Station on the Yonge North Subway Extension (YNSE), the initial concept retained three lanes on a fully traffic decked Yonge Street over the station footprint. Constructability reviews and schedule optimization led to a pivotal redesign: a five-lane bypass tying into adjacent intersections, relocating live traffic away from the excavation zone to open larger work faces, reduce risk, and accelerate works. 

Geometric and Technical Design 

Design decisions followed the TAC Geometric Design Guide, OTM Book considerations, and MTO standards for temporary traffic control and geometry. Traffic analysis using Synchro and AutoTURN determined lane requirements by stage and informed intersection tie-ins. Temporary signal warrants and illumination were addressed to maintain user safety. Utility and drainage coordination focused on catch basin placement, flow paths, and resolving conflicts with existing utilities, while constructability was managed separately to secure laydown areas, equipment access, and needs within the constrained right of way. Horizontal alignment refinements and vertical profile coordination were undertaken at tie-in intersections to maintain sight distance, drainage, and barrier continuity, while turn lanes and queuing storage were sized to meet peak demand across stages during peak periods. 

Community Input and Accessibility 

Community and stakeholder input shaped the plan at each stage. Transit accessibility remained a priority through coordination with TTC and regional providers (e.g., YRT, GO), including temporary bus stop relocations, perseveration Mobility Shelter Hub for Wheel-Trans (TTC) to be maintained throughout construction, clear wayfinding, and lighting. Sidewalk realignments preserved pedestrian desire lines and minimized out of direction travel, and AODA compliant intersection designs, tactile indicators, accessible curb ramps, optimized phasing, and marked crossings were implemented and reverified as staging evolved. Detours were minimized by prioritizing direct bypass movements and limiting turn restrictions to essential safety or sequencing. 

Constrained Corridor 

A major constraint was Morguard’s Centerpoint Mall, requiring sequenced construction to maintain access for customers, deliveries, and emergency services. This condition influenced staging windows, lane allocations, tiein timing, and required merchant coordination to mitigate impacts. The approach demonstrates how data driven analysis, space allocation criteria, and multiagency collaboration deliver safe, accessible, constructible solutions in constrained corridors.  

Lessons learned: early constructability reviews, transparent engagement, and iterative signal/geometry refinement are transferable to future subway and arterial projects.