Presented a highway motor vehicle collision warning systems, autonomous speed highway-vehicle devices on vehicles, and to determine whether the vehicle speed set security value below the highway automatically, you can manually send message warning, freeway on-ramp test starter on highway vehicle performance testing device, start the highway-vehicle device, set up safe speed limit, Highway closed highways closed device-vehicle device features Highway direction of travel frequency settings, device settings Highway truck-mounted communications device in the highway direction frequencies, expressway monitoring and communication device real-time monitoring of vehicle travel, and while the vehicles are in normal form, anti-collision warning output; The highway vehicle collision warning systems can be monitored in real time and receive the abnormal traffic safety warnings ahead, sent the safe speed limit values due to weather and road conditions change, improves the safety of highway traffic.