• A traffic control signal (Traffic Signal) is a type of highway traffic signal by which traffic is alternately directed to stop and permitted to proceed
  • Traffic control signals are described as either pre-timed or traffic-actuated
  • Under pre-timed control duration of red, green, and yellow intervals are predetermined
  • Under traffic-actuated control, the duration of green intervals varies according to traffic demands
  • Traffic control signals are valuable devices for control of vehicle and pedestrian traffic and usually have one or more of the following advantages:
    • They provide for orderly movement of traffic
    • They can increase the traffic handling capacity of an intersection
    • They can reduce the frequency of certain types of accidents, especially the right-angle type
    • They can be coordinated to provide for continuous or nearly continuous movement of traffic at a definite speed along a given route
    • They can be used to interrupt heavy traffic at intervals to permit other traffic, vehicular, or pedestrian to cross