Placement of Traffic Signals

From time to time, our Traffic Engineering Division is asked how placing a traffic signal is determined. Traffic engineers cannot simply install traffic signals where they are not warranted. Traffic signals are expensive and the incorrect placement can actually be harmful. Refer to the Manual of Uniform Traffic Control Devices (MUTCD) for the 11 warrants for the placement of traffic signals. A traffic signal should not be placed if one of these warrants has not been met.

There are some general objectives in placing a traffic signal. Good engineering judgment must be made in order to balance among these objectives. According to the MUTCD, traffic engineers assess these four goals when allocating the right-of-way to traffic:

1.   moving traffic in an orderly fashion,
2.   minimizing delay to vehicles and pedestrians,
3.   reducing crash-producing conflicts, and
4.   maximizing capacity for each intersection approach.