Traffic signals assign the right-of-way to various traffic movements for different time intervals depending on average traffic flow levels. Pre-timed signals have pre-set intervals for different times of the day including the morning, noon and evening peak travel periods. The City has a few fixed-time signals, primarily in construction areas.
Traffic actuated signals use detectors located in the pavement on the approaches to traffic signals to monitor and assign the time intervals for right-of-way on the basis of changing traffic demand. These signals assign most of the available green time in a cycle to the heaviest traffic movement.
As staff continues to improve traffic signal progression within the City, it is important that the public officials and the public understand the limitations of traffic signal coordination. While traffic signal coordination can reduce travel delays on the entire City street system, travel along a particular street may not completely experience free-flow conditions due to the following:
Complexity of the City's street system
Street construction/Traffic incident
Increased traffic caused by growth both within and outside of the City
Coordination with agencies (i.e. cities, Caltrans and County).