What is the past and present of the vehicle detector?

A more standard term for vehicle detectors should be: traffic information detectors. In traffic detector systems or traffic information acquisition systems at home and abroad, a large number of magnetic sensing technologies, ultrasonic sensing technologies, radar detection technologies, and video detection technologies are used in traffic detector systems or traffic information acquisition systems. , Computer technology, communication technology and other high-tech technologies. The main traffic information detectors are: inductive loop detector (ring-type induction coil), ultrasonic detector, infrared detector, radar detector.