For city traffic management, an underground induction winding is used to identify vehicles inside the red light forbidden zone in most computer monitoring systems at traffic lights. We described how to apply video motion detection (VMD) technology in these computer surveillance systems instead of underground induction windings. Using VMD eliminates the underground induction windings that damage road surfaces. The possibility of applying and implementing VMD technology with supporting hardware was analyzed. We described how to develop the program to record automatically those vehicles that violate traffic rules at traffic lights, and to obtain the traffic status of and evidence about those vehicles.