There are generally two kinds of cameras we see on the road, illegal capture and regular registration. As for routine registration, let me explain the purpose of this camera, which is to record the license plate, vehicle type and traffic volume. When necessary, police comrades can use these photos to track down cases and criminals. The other is illegal evidence collection. "Flash" 1 time may be recorded information, but if it is found that it has been flashed many times, it may be illegally recorded. Take judging the violation of red light as an example. Generally, it takes at least three pictures to determine: 1, before the vehicle passes the stop line; 2. When the vehicle exceeds the stop line; 3. The rear of the car keeps moving after leaving the stop line.