How does a traffic light detect a car?

Traffic lights typically detect cars using several methods, the most common being inductive loop sensors embedded in the road surface. These sensors consist of wire loops that create a magnetic field; when a vehicle passes over or stops above them, the metal in the vehicle disrupts the magnetic field, signaling the traffic light to change. Other detection methods include infrared sensors, cameras, and radar, which can monitor vehicle presence and movement. These systems help optimize traffic flow and improve safety at intersections.