Traffic Signal Operations and Standards

Traffic signal operations

A traffic signal is a complex system made of many components. Structural signal poles hold the traffic signal displays, traffic signal cabinet, traffic signal controller, multitude of sensors to provide input information for traffic controller, various communication equipment, electronic components, fiber optic cabling, electrical wiring and a traffic controller make up majority of a signal system. The traffic signal controller is brains behind the operation and is housed in a traffic signal cabinet. The Traffic controller operates the intersection and allows for collects of data for further analysis. Each of the City’s 807 traffic signals have a signal controller. The controller interprets data received from roadway sensors actuated by pedestrian, bicycles, and vehicles to determine if a direction needs service and it assigns that direction the appropriate amount of time. Additionally, there are other variables programmed at some location for Heavy Rail crossing, Light Rail operation and emergency vehicle such as fire trucks. Not all signalized intersections are the same. Some have Intersection do not have sensors. Intersection is downtown for instance do not have roadway sensors and run a fixed amount of time for each direction.

As traffic signals are designed to provide control to more types of roadway users, the operation of the traffic signal becomes more complex. The traffic signal assigns right of way to road users including, pedestrians, bicyclists, motorists, rail, transit, and emergency vehicles so the intersection operates as safely and efficiently as possible. These road users compete for the valuable time it takes the signal to cycle. Roadway sensors reduce the time it takes serve awaiting road user by allowing the signal to move on to direction that do not need service or when condition do not warrant the maximum amount of time. An efficient operating traffic signal is a safer intersection since it operating as road users expect.

Traffic signal standards

Construction Standards 

Standard Specifications (Updated November 2020)

Standard Drawings

Traffic Signals and Streetlighting

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