TRANSPORTATION OPERATIONS | SIGNALS

There are approximately 850 signalized intersections in San Jose. The Department of Transportation determines where traffic signals are needed, and operates and maintains them after they are installed.

Requests for New Signals
New signals are requested by citizens, other public and private agencies, council members and other City departments. Before the City Council will consider installation of a signal, a standardized signal study must be performed and established minimum criteria must be satisfied.

A signal study considers:

• The number of vehicles and pedestrians.
• The intersection's accident history.
• The intersection's proximity to major traffic routes, other traffic signals, schools and parks.
• Unusual conditions such as road curvature.

Selection and Funding Of New Signals
The Department of Transportation maintains a priority list of all locations meeting the minimum criteria for a signal. The ranking of each location is determined by the results of the most recent signal study. Based upon the signal priority list and the available budget, the City Traffic Engineer recommends new signal installations each year to the City Council. Most traffic signals are funded through the City's Capital Improvement Fund. Others are financed by developers as part of residential or commercial construction projects. A typical traffic signal installation costs approximately $275,000.

Benefits and Disadvantages of Signals
A traffic signal I can dramatically change the traffic patterns in and around an intersection. When evaluating a potential signal, full consideration of the benefits and disadvantages of signalization must be given.

Benefits of Signals
When installed under conditions that justify its use, a traffic signal can:

• Interrupt extremely heavy flows to permit the crossing of minor movements that could not otherwise move safely through an intersection.
• Increase the traffic handling capacity of an intersection.
• Reduce certain types of accidents, most notably right-angle (broadside) collisions.

Disadvantages of Signals
Unwarranted or inappropriately placed signals can:

• Increase overall travel times by adding stops and delay for through traffic.
• Cause the diversion of traffic onto residential streets to avoid the signal.
• Cause a significant increase in rear-end collisions.