That is correct in some cases in Toronto - but only downtown, and only during rush hours. At other times, and everywhere else in the City, the lights are not coordinated.
This is actually almost backward.
Almost all traffic signals are coordinated during the day (7 AM to 10 PM at least), in the sense that they operate with a controlled relationship with other nearby signals in a group. Our most advanced signal system,
SCOOT, actually updates the relationship between the intersections on the fly using real-time volume information. This system is not surprisingly more effective at keeping cars moving than non-adaptive systems, especially since signals are sometimes added or modified without manually recoordinating the entire stretch of street. Streets with SCOOT include Don Mills, Yonge Street near the 401, Black Creek Drive, and Lakeshore Blvd. The signal system for every traffic signal in the city is available here:
https://www.mirasan.ca/.
The non-adaptive systems are called "MTSS" and "TransSuite". We are currently transitioning from the former to the latter, which is more flexible. These systems typically use three timings (called "plans") during the day: AM Peak, Midday and PM Peak. Each plan may have a different offset from other signals as directions of travel are prioritized throughout the day.
The exception to co-ordination is any signal which uses transit priority (i.e. many signals downtown). These signals fall out of co-ordination when the extended green lights extend signal cycle beyond its normal value. They typically take about 3 cycles to re-sync, by which time another vehicle may have shown up and requested priority, restarting the situation.
Most of the lights are coordinated via computers. However, if the intersection has four directions, only one direction would be coordinated. Which means 3 out of the 4 are not.
This is all correct. The traffic operations centre in Flemingdon Park is the "brain" of the entire city's traffic signals, as long as the communications are working. When communications are lost, signals operate on the built-in controller and can fall out-of-sync with other signals.
It is very important to underline that in Toronto it is not possible to co-ordinate in more than one direction at a time, so most signals will not seem co-ordinated to the average driver. And in some cases, the chosen offsets are a compromise in delay between the directions, which gives the impression that there is no co-ordination.
All of this media attention about co-ordination is about nothing other than cars. Good co-ordination from the point of drivers really screws up transit in the absence of transit priority.
Sorry about derailing the thread. To get slightly more on-topic, I hope that the higher capacity of the new streetcars encourages traffic engineers to more aggressively prioritize transit at signals, given that doing is now more likely to reduce person-delay at the intersection.
