Implementation of a V2P-Based VRU Warning System With C-V2X Technology

Abstract

Cellular vehicle-to-everything(C-V2X) technology can protect vulnerable road users(VRUs) in traffic accidents. Smartphones are the most common portable devices for VRUs, but they do not support direct communication between vehicles and pedestrians. To address this problem, we propose a vehicle-to-pedestrian collision warning system that includes a phone case designed for the smartphone. It allows VRUs to communicate directly with connected vehicles(CVs) through C-V2X. A collision warning method based on s-t-coordinates is proposed to help VRUs to avoid collision with CVs on both straight and curved roads. Firstly, the World Geodetic System-1984(WGS-84) coordinates of the VRU and CV are transformed to Universal Transverse Mercator(UTM) coordinates. Then the s-t-coordinates of the VRU and CV are calculated. The lateral and longitudinal distance between them is determined. Finally, the time-to-collision(TTC) is used to determine the time to alert the VRU and the driver. To verify the effectiveness of this system, we conduct experiments on communication, positioning, and scenario. The communication experiments show that the system can communicate effectively with low latency and its reliable communication range is more than 200 meters in different scenarios. The positioning experiments show that the average positioning accuracy of the phone case is 0.83 meters in the open-sky scenario, which satisfies the lane-level positioning requirement for VRU applications. The scenario experiments indicate that our method can alert the driver and VRU on both straight and curved roads. The comparative experiments illustrate that our method outperforms the conventional method(CM) and the existing pedestrian alert system(PAS).

Keywords

• C-V2X
• VRU
• smartphone
• V2P
• phone case
• connected vehicle