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.

The City of Irvine is involved in a number of Intelligent Transportation System (ITS) activities in cooperation with the Federal Highway Administration, State of California Department of Transportation (Caltrans) and leading research organizations such as the University of California Transportation Studies at UC, Irvine. The City of Irvine is a partner to the California Research Program with Caltrans and UC, Irvine that is designed to demonstrate the capabilities of real-time interconnectivity and data sharing between organizations.

In addition, the City Traffic Engineers are working on the following projects to further minimize travel delay:

Installing additional cameras to monitor and correct signal timing from the traffic management center (ITRAC) Applying mobile wireless cameras to monitor traffic congestion locations throughout the city. Installing additional video detection systems Installing detection monitoring at ITRAC to improve the traffic circulation at all city-maintained signalized intersections. Submitting grants for additional funds on projects that help signal coordination Working with adjacent agencies to provide coordination across jurisdictional boundaries Coordinate major travel corridors in the City.

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 Equipment malfunctions Coordination with agencies (i.e. cities, Caltrans and County).

The City is committed to providing the safest, most efficient and advanced Traffic Signal System available. If you have any community traffic concerns, questions, or suggestions, please call the Irvine Traffic Research and Control Center (ITRAC)
at (949) 724-7324.