What is the main purpose of a traffic signal?

The main purpose of a traffic signal is to control traffic flow at intersections. Traffic signals are designed to provide a systematic way to manage the flow of vehicles and pedestrians, ensuring that different streams of traffic can proceed safely and efficiently. By alternating the right of way through lights that change from red to green, these signals help prevent accidents and reduce congestion at busy intersections.

While managing pedestrian crossing and signaling vehicle speed may be secondary functions of traffic lights, their primary role is about controlling traffic movement. This is illustrated by how traffic signals are strategically placed to dictate the flow of vehicles from various directions at an intersection, thus enhancing overall safety and orderliness on the roads. Traffic signals also indirectly support pedestrian crossing by allowing for safe opportunities for pedestrians to cross when vehicles are halted.