About Traffic Signals Will traffic signals help reduce the number of accidents at intersections?
Properly placed and warranted signals can improve the overall flow of traffic, but they do not always prevent accidents. Very often, accidents of certain types increase after traffic signals are installed. Signals can be very effective in reducing right-angle collisions, but they could lead to increases in “rear-end” type collisions and other kinds of accidents. Some pedestrian-related accidents may occur because pedestrians get a false sense of security when crossing signal-controlled streets. According to conclusions drawn from two studies recently conducted here in California, signals may have an adverse effect when installed at sites where there were only minor problems prior to the installation of the signals. The first study included more than 1,000 new signals and the second included 24 major California cities. A related third study, called the Schoene study, warns of a possible increase in accidents whenever signals are installed at intersections where there were fewer than 10
