How to trigger traffic light sensors?

The triggering of traffic signal sensors mainly relies on geomagnetic induction coils or infrared detection devices embedded in the road surface. When a geomagnetic sensor detects a metal object (such as a vehicle chassis) altering the magnetic field, or when an infrared sensor's light beam is obstructed by a vehicle, it sends a signal to the control system to trigger a green light switch. Modern intelligent transportation systems also employ multi-sensor fusion technology, such as combining radar speed measurement with video analysis to dynamically adjust green light duration through algorithms. Drivers are advised to stop as close to the stop line as possible or position their vehicles directly over the induction coil area. Some intersections have now been upgraded with optical sensors that enhance detection sensitivity for various vehicle types through contour recognition technology, maintaining stable operation even during extreme weather conditions like heavy rainfall.