What is the primary function of a traffic signal?

The primary function of a traffic signal is to alternately assign right-of-way to various movements at an intersection. Traffic signals serve to coordinate and control the flow of traffic, ensuring that vehicles and pedestrians can safely navigate the intersection. By alternating the phases of green and red signals, traffic signals manage the competing demands of different road users, facilitating safe and efficient movement.

This function is crucial for preventing collisions at intersections, where multiple traffic movements converge. By clearly indicating when drivers should stop and go, traffic signals help establish an orderly sequence of movement based on traffic demands and road user types. While other functions of traffic signals, such as increasing intersection capacity, protecting pedestrians, or minimizing delays, are important considerations in traffic engineering, the fundamental role of a traffic signal is primarily about managing right-of-way.