A traffic signal warrant study is used to determine if traffic control devices are needed at a specific intersection. A device is considered warranted if it passes this test. However, the traffic control device may not appear as approved for construction on the warrant list for different reasons, such as budget constraints or community association concerns.
After a citizen has made a service request for a new traffic signal it is received by a Traffic Signals Engineer who then investigates the last time, if ever, a warrant study has been completed at the location of concern. If a warrant study had been conducted within two years of the request date it will NOT be conducted again under normal circumstances.
Request a new Traffic Signal warrant study - eService
If a new warrant study has been deemed necessary, it will be sent to Transportation Data to have a traffic count completed. Usually, traffic counts are completed during peak hours of the day to capture the highest volumes of traffic and pedestrians present at the intersection. It can take 4 – 9 months for a traffic count to be returned to the Traffic Signals group because the counts are often conducted in the spring and the fall by seasonal staff.
With the returned traffic count data, the Signals Engineer can now conduct the warrant study that takes in account:
- Traffic volume.
- Pedestrian volume.
- Proximity of adjacent signalized intersections.
- Transit Routes.
- Number of lanes from all approaches to the intersection.
- Posted traffic speed.
- Demographics of the immediate area.
All of these factors are calculated and a score is produced that will determine if a traffic signal is warranted at the specific location.
If the score is 100 or higher the traffic signal is warranted and will be sent to Signals Design to determine if it fits into the available budget. It may be built the following year in a priority sequence.
If the score is between 80 and 99 the traffic signal is not warranted. It is sent to Transportation Data for a new traffic count, to have another warrant study completed every year until the score rises or falls enough to no longer remain in this range.
If the score is 79 or lower the traffic signal is not warranted. A new warrant study will not be conducted again for two years under normal situations.
Intersections which have had a warrant study completed
An outline of the completed traffic signal warrant studies can be viewed in the Traffic signal warrant list.