Evaluating Redundancy Mitigation in Vulnerable Road User Awareness Messages for Bicycles

Vehicle-to-X (V2X) communication has become crucial for enhancing road safety, especially for Vulnerable Road Users (VRUs) such as pedestrians and cyclists. However, the increasing number of devices communicating on the same channels will lead to significant channel load. To address this issue this study evaluates the effectiveness of Redundancy Mitigation (RM) for VRU Awareness Messages (VAMs), focusing specifically on cyclists. The objective of RM is to minimize the transmission of redundant information. We conducted a simulation study using a urban scenario with a high bicycle density based on traffic data from Hannover, Germany. This study assessed the impact of RM on channel load, measured by Channel Busy Ratio (CBR), and safety, measured by VRU Perception Rate (VPR) in simulation. To evaluate the accuracy and reliability of the RM mechanisms, we analyzed the actual differences in position, speed, and heading between the ego VRU and the VRU, which was assumed to be redundant. Our findings indicate that while RM can reduce channel congestion, it also leads to a decrease in the perception rate of VRUs. The analysis of actual differences revealed that the RM mechanism standardized by ETSI often uses outdated information, leading to significant discrepancies in position, speed, and heading, which could result in dangerous situations. To address these limitations, we propose an adapted RM mechanism that improves the balance between reducing channel load and maintaining VRU awareness. The adapted approach shows a significant reduction in maximum CBR and a less significant decrease in VPR compared to the standardized RM. Moreover, it demonstrates better performance in the actual differences in position, speed, and heading, thereby enhancing overall safety. Our results highlight the need for further research to optimize RM techniques and ensure they effectively enhance V2X communication without compromising the safety of VRUs.