Abstract Manager

No Right Turn on Red (NRTOR) restrictions and Fully Protected Left Turns (FPLTs) have gained traction across many jurisdictions to mitigate collisions involving right- and left-turning vehicles, in particular with pedestrians. While both treatments can reduce collisions at intersections, drawbacks include increased congestion and delays, reduced intersection efficiency, and increased queues. Therefore, it is important to strike a balance between traffic operations and road safety and ensure that NRTOR restrictions and FPLTs are implemented at locations with appropriate characteristics. To this end, the City of Mississauga has indicated a desire to implement NRTOR restrictions and FPLTs through a data-driven approach to identify locations best suited for each treatment.

A literature review and a jurisdictional scan were conducted to identify the factors influencing site selection for NRTOR restrictions and FPLTs. Other topics explored through the literature review include the benefits and disbenefits associated with both treatments, the potential for time-of-day implementation, actuation of NRTOR restrictions, a City-wide ban on RTOR, leading and lagging FPLTs, and interactions with Leading Pedestrian and Leading Bicycle Intervals. Collision analysis was also undertaken to understand trends across the City with respect to collisions involving a left- or right-turning vehicle. Safety Performance Functions were developed, and network screening was conducted for left- and right-turn collisions. This analysis was conducted based on total collisions and collisions involving vulnerable road users separately to identify priority locations with the greatest potential for improvements. The top-ranked locations could be used as a starting point for evaluating the need for NRTOR and FPLT treatments.

Based on the literature review and jurisdictional scan results, scoring matrices were developed to evaluate different sites for implementing NRTOR restrictions and FPLTs, with factors including the presence of pedestrian generators, collision history, intersection sightlines, and other criteria. A methodology for site selection was eventually established, including an office review, a field investigation, an evaluation of mandatory requirements for FPLTs and NRTORs, and scoring using the developed scoring matrices. Finally, an analysis of the implications of this policy on costs and resources was undertaken, and an evaluation process was developed to continuously monitor the operational and safety impact of these treatments.