The Transportation Division determines the need for new signals and modification to existing signals. There are approximately 125 traffic signals in the City of Palo Alto. The Transportation Division determines the need for new signals and modification to existing signals. The signals on El Camino real are under the jurisdiction of CalTrans and the signals on the Page Mill/Oregon and Foothill Expressways are under the jurisdiction of Santa Clara County.
Traffic signals, like stop signs, are intended to provide right-of-way control at intersections. Traffic signals have the additional advantage of increasing the traffic handling capacity of the intersection, reducing the frequency of certain types of accidents, and allowing for the progressive movement of traffic along a corridor.
The justification for the installation of a traffic signal is based on warrants established by CalTrans and the Federal Highway Administration. The warrants include minimum vehicle volume, minimum pedestrian volume, accident history, and delay. Because the installation of a traffic signal may increase the frequency of some types of accidents and increase overall delay, the decision to install a signal is not based solely on the warrants and a thorough study of traffic and roadway conditions must be undertaken before a traffic signal is installed.
A typical traffic signal installation can cost $200,000 or more, depending upon the complexity of the signal. In addition, annual costs for electricity and maintenance must be paid to keep the signal operational. Consequently, adequate resources must be available before the decision to install a traffic signal is made.