In the era of automation, the transport system should be proactive to avoid accidents due to high traffic population. In this work proposes a vehicle-to-vehicle communication protocol for comparative collision warning. The wireless data communication between two vehicles is provided by introducing ZigBee technology. It is designed around low-power consumption allowing batteries to essentially last forever. The distance measurement is provided by ultrasonic sensors. Ultrasonic sensors are transmitting and receiving ultrasonic signals. Road accidents account for a severe threat to human lives from both an injury as well as a financial perspective. Today, special attention is focused on the technologies that can reduce traffic accidents. The microcontroller controls entire process, it is programmed to send a signal to buzzer and ZigBee when the distance range is obtained. The main objective of this project is to alert the driver when he is close to the front vehicle.