Frequently Asked Questions


Traffic Signal Timings and Coordination


St. Albert is growing, both in population and development.  Increasing traffic volumes, the building of new roadways and a diverse group of road users create an ever changing demand on our transportation system. Throughout all of this, the City is maintaining a critical eye on the traffic patterns to ensure both safety and efficiency during drivers’ commutes.

To keep you informed, the City has answered some of your top questions regarding traffic signal timings and coordination in St. Albert. Keep watching for future updates.
  1. There seems to be traffic lights at almost every intersection on the major roads and main arterials. How do you determine light placement and sequencing?
  2. Why does it feel like I’m waiting such a long time at some traffic lights? 
  3. Why do some intersections have left-turn arrows while others don’t? 
  4. The timers on the walk lights are a significant benefit to anticipating a light change. Will they be expanded throughout St. Albert? 
  5. There seems to be more cars on the road than ever before. What is the City doing to stop traffic congestion?

1. There seems to be traffic lights at almost every intersection on the major roads and main arterials. How do you determine light placement and sequencing?
Potential locations for Traffic Signal Placement are recognized through:
  • communication with the public over safety concerns or complaints at specific locations,
  • annual traffic counts recognizing increased volumes on roadways, and
  • the recognition of future urban development.

Traffic Signal Placement is then verified through the use of the Transportation Association of Canada, Canadian Traffic Signal Warrant Matrix Procedure (2005). The key determining factor for identifying the need for traffic signal control is the conflict between the stream of traffic on the main street and the vehicles, pedestrians/cyclists on the side street (desiring to access or cross the main street).

The sequencing or timings of the traffic signals are a direct relation to traffic volumes or demand for each individual movement at an intersection. The safe movement of the largest volumes of vehicles through the intersection is the goal for the signal timings. This means that signal timings may be adjusted throughout the day to account for varying demands.

2. Why does it feel like I’m waiting such a long time at some traffic lights?

Traffic signals operate on Cycle Lengths. A Cycle Length is the time it takes for a signalized intersection to complete all phases of vehicle and pedestrian movements.  This is the time it takes for a signal (one direction of travel) to go from green to amber to red and back to green again. All phases or traffic movements must be allowed a portion of time (vehicles, left-turns, pedestrians). In St. Albert, the Cycle Lengths are typically 110 to 120 seconds during the peak periods, 100 seconds during off peak periods and 75 seconds during night time periods. This keeps the flow of traffic moving efficiently and safely.

In order for coordination to be created between traffic signal locations along a shared roadway corridor, the cycle lengths for each intersection must be the same.

For pedestrians, timings are configured to the width of the roadway being crossed. St. Albert typically provides pedestrians with longer walk periods than what the minimum Canadian standards call for (3 ft/second of travel time) to provide increased protection and safety.

3. Why do some intersections have left-turn arrows while others don’t?

Each year, the City studies existing traffic volumes throughout numerous locations in St. Albert. The results from these locations determine future actions for traffic signals such as signal placement, upgrades or redesigns.

Volume of traffic and the demand for the left turn movement plays a significant role in determining whether a left-turn signal will operate at an intersection. This helps explain why some locations have left turn arrows operating at only certain times of the day.

4. The timers on the walk lights are a significant benefit to anticipating a light change. Will they be expanded throughout St. Albert?

Yes. Multiple sites are scheduled to have the Pedestrian Countdown timers put in place. This is a program that the City would like to continue into the future. The key consideration is that the countdown timers are meant for pedestrian use. Although they may be perceived as a benefit to drivers, Pedestrian Countdown timers operate under conditions that will vary and certain conditions may not always be available for the driver to take advantage of.

5. There seems to be more cars on the road than ever before. What is the City doing to stop traffic congestion?

As St. Albert grows, so does the demand on our roadways. The City is utilizing new technology to optimize our corridor systems. Radio communication between traffic signal locations, video detection for vehicles, and an upgraded warrant study program are ways the City is collecting further information and making ongoing changes to better suit the ever-increasing and changing volumes of traffic and traffic patterns.

For further information on roadways transportation in St. Albert, please contact: Dean Schick, Transportation Systems Coordinator, dschick@st-albert.net or call 780-459-1649.