Traffic Signal Operations
The City's Traffic Signal Operations Group deploys advanced technology on the roadway system in a strategic manner. The technology is networked into the Traffic Operations Center so traffic signals can be coordinated. The City’s operations staff strives to be a leader in using such technology in our region.
How a Traffic Signal Works
A traffic signal is a complex system made of many components, the poles that hold the traffic signal heads are only a small part of this system. There are a multitude of sensors and electronic components that comprise the majority of a signal system. The brains behind the operation are enclosed in a traffic signal controller cabinet.
Each of the City’s 700 traffic signals has a signal controller. This controller is basically a micro computer that interprets data received from roadway sensors and assigns the appropriate amount of time for a given direction. In cases where intersections are within a close proximity, like downtown, the signal controllers run a fixed amount of time for each direction, to facilitate coordination between the intersections. At other locations, sensors are in place that are actuated by vehicles and help the controller know where the vehicles are on the road. Operations staff program specific parameters into both fixed time and actuated signals that are then interpreted by the controller. Many of these controllers allow these parameters to be remotely programmed through communication with the City’s Traffic Operation Center.
Traffic signals interact with more than just cars. Parameters for these other variables also need to be programmed. Pedestrians, bicyclists, fire trucks and light rail trains all need to be serviced at a signalized intersection. All these variables are integrated into the operation of the signal.
Want to Know More?
Visit our questions and answers section for answers to these common traffic signal questions and more:
- What happens when a traffic signal malfunctions?
- Are traffic signals coordinated from one to another?
- What do pedestrian crossing indications mean at a signal?
- How do traffic signals detect cars?
- Why are there cameras at some intersections?
- Do trains or light rail affect the signals?
- Can Emergency vehicles cause the signal to change?
- What does a traffic signal cost?