One of the fundamental parts of the City’s MoveTO action plan is to maintain signal timing plans to ensure they are up-to-date and responsive to the needs of all road users. The aim of the City’s Signal Optimization Program is to undertake signal coordination studies on a five-year cycle for major arterial roads, and on a 10-year cycle for minor arterial roads. Within the five-year cycle, a one-time study may be required for a portion of the route if there are significant changes in traffic volumes or land use. Coordination studies are not undertaken for traffic adaptive systems, such as SCOOT and SCATS.
The City uses Synchro® software to develop optimized signal timings plans. Studies are done in conformity with the City’s Guidelines for Using Synchro 11 (including SimTraffic 11).
View the map and list of all Toronto optimized (coordinated) signals that were completed during the 2012-2022 period. View the list of all Toronto optimized (coordinated) signals that are in progress and will be completed by December 31, 2023.
The terms “signal retiming”, “signal coordination” and “signal optimisation” are often used interchangeably.
Toronto’s Signal Optimization Program is a coordinated effort designed to make the most efficient use of Toronto’s 2,487 traffic signals (as of May 26, 2023) by improving traffic signal operations. “Optimization” in this context refers to all maintenance, upgrades, timing adjustments, and miscellaneous efforts to improve our signals.
The basic goal of signal coordination is to minimize delays to vehicles travelling at or near the speed limit through a series of signalised intersections. The coordination strategy can vary depending on the road classification, time of day and directional traffic flow.
If you have a concern about a particular route, you can contact 311 and provide the details of your concern, including the following:
311 staff will relay your concern to the Traffic Systems Operations (TSO) unit. TSO staff will contact you if any clarification is required.
City staff start by gathering data for each intersection along the route to establish the most up-to-date travel patterns. Once the data is gathered, engineers use computer programs to develop the best timing scenarios for each intersection on both an individual intersection and a route basis. Generally, signal timing plans are developed and/or updated for six periods – morning peak, day off-peak, afternoon peak, evening off-peak, night, weekend. Traffic diversion plans are also developed for routes that run parallel to the City’s expressways e.g. Leslie Street or Victoria Park Avenue.
As the goal is to minimize overall delay throughout the road network, drivers can expect to be stopped less frequently with the busiest traffic movements being given precedence over the less busy traffic movements. For example, the Leslie Street signals were generally coordinated with preference to southbound traffic in the morning peak period, northbound traffic in the afternoon peak period, and both directions during all other periods.
Signals are grouped into zones that are called control areas that can change by time of day. Generally, the control areas in the morning and afternoon peak periods are bigger since our aim is to move platoons of traffic to reduce travel time, stops, vehicle delay and fuel consumption. In the off-peak period, we operate major/major intersections (such as Leslie Street and Sheppard Avenue) by themselves because of their operating characteristics. Drivers may encounter delays when the control areas change.
Signals on the City’s major arterials are coordinated all the time. Signals on the City’s minor arterials and collectors are coordinated at all times except overnight generally between 10 p.m. and 6 a.m.. During the non-peak times, there are fewer cars on the minor arterials and collectors and therefore less benefit from coordination to the overall driving public. In addition, drivers are less willing to accept the side street delays.
Measures of Effectiveness (MOEs) are measurable parameters that demonstrate the benefits, impacts, and cost-effectiveness of signal timing plan alternatives for the individual intersection, associated route and entire network. The City uses these parameters to evaluate the effectiveness of signal coordination studies. The following MOEs are reported: vehicle delay (hr), stops (#), average speed (km/h), fuel consumed (L) and greenhouse gas emissions (kg). In addition, an overall benefit-cost analysis is developed for each individual corridor.
The 2012 – 2016 studies have resulted in reductions in overall vehicle delay, travel time, vehicle emissions, stops and fuel consumption on the routes that were optimized; there was a slight increase in vehicle speed on these routes.
Based on the United States Environmental Protection Agency’s Greenhouse Gas Equivalencies Calculator, the reduction of fuel consumption achieved by the 2012-2016 studies is equivalent to the reduction of carbon dioxide emissions from 6,458 homes’ electricity use for one year or carbon sequestered by 41,395 acres of forest in one year.
The benefit/cost ratios from 2012 to 2016 were between 33:1 and 75:1 with a total cumulative saving over the three-year life cycle period of $271.1 million across all routes. The total life cycle benefit/cost ratio is estimated at 53:1. This means that for every dollar invested by the City, there was a potential saving of $53.00 to the public.
Signal coordination is subjected to a number of constraints which limit the City’s ability to provide perfect coordination over long stretches of roadway. Such limitations include changes in roadway environment, midblock traffic disruptions (e.g. driveways, on-street parking, pedestrian crossovers), and the competing roadway demands of pedestrians, bicyclists, transit vehicles, and cross-street traffic. It is also inherently much more challenging to provide perfect coordination on two-way corridors compared to one-way streets. Hence, while we are able to provide nearly perfect coordination along routes such as Adelaide Street and Richmond Street where we are coordinating in one direction only, we cannot achieve the same performance level along routes such as Leslie Street since we must accommodate for two directions of travel.
Toronto’s traffic control systems optimizes the movement of pedestrians, cyclists, vehicles and transit. However, once the volume of traffic reaches the road capacity (which varies by street and is dependent on the number of lanes, the directional mix of traffic, the complexity of the intersection, the presence of cycling lanes, etc.), travel time will increase. However, the system minimizes the delay experienced compared to operating the city streets without the system. Also, as population continues to increase, if driving also increases, traffic may get worse even with the systems being fully operational.
No traffic signal system is capable of “fixing traffic.” Our systems continue to enable optimal street operations while achieving a balance between safety and mobility. While Toronto continuously reviews signal timing to optimize signal coordination on major streets, perfect signal coordination on every street, at every time of day, and under all traffic conditions, is impossible.