Implementation and performance measurement of a V2X communication system for vehicle and pedestrian safety

The dedicated short-range communication/wireless access for vehicular environment together with the fourth generation-long-term evolution technologies has been widely accepted as the most promising approaches to enhance the transportation safety. As pedestrians are still protected based on the traditional honking approach, the communication-based safety alert is questionable in the practical usage. In this article, a dedicated short-range communication/long-term evolution/WiFi-based vehicular system is developed to support the vehicle-to-vehicle and vehicle-to-pedestrian communication for the safety of vehicles and pedestrians. The implementation of the heterogeneous vehicle-to-vehicle/vehicle-to-pedestrian communication module is based on an IEEE 802.11a compliant communication module, integrated with the long-term evolution module and WiFi wireless interface. A collision estimation and safety alert module on smartphone is further designed and implemented to protect pedestrians. Various performance evaluation experiments are carried out under different scenarios via an uncontrolled approach, including the university campus, typical urban streets, and suburban districts. The packet delivery rate and end-to-end latency in each scenario are recorded and analyzed based on non-line-of-sight/line of sight cases. Experiment results reveal that IEEE 802.11p based vehicle-to-vehicle communication is unstable in the non-line-of-sight conditions, while the cellular-based performs better in the transmission reliability but has larger latency than IEEE 802.11p. The WiFi based vehicle-to-pedestrian communication is efficient when the transmission distance is less than 150 m.