Validation of a bike simulator for ADAS impact analysis: Road projection communication system with reversing scenario case study

Cycling is an eco-friendly mode of transportation with social and environmental benefits. However, cyclist fatality rates in Europe have not shown improvement, with most fatalities occurring during car-cyclist interactions. The Communication-Oriented Advanced Driver Assistance System (CO-ADAS) introduces a light-based visual communication, projecting patterns onto the ground to indicate the vehicle's intended movement, enhancing cyclists' anticipation. Evaluating CO-ADAS in on-road experiments is constrained by safety and controllability. Virtual reality (VR) bike simulators offer a safer and controlled alternative, yet the validity of simulator-based evaluation is little discussed, especially for novel interactions like CO-ADAS, which is an unfamiliar interaction type and may elicit surprising effects. This study addresses the validation of simulator-based evaluations for an unfamiliar interaction type (CO-ADAS) and highlights the challenges of simulator validation via statistical analysis. It also emphasizes the importance of video data for action recognition and for capturing complex behavior. To this end, cyclist interactions with the CO-ADAS projection were compared between on-road and VR experiments across three levels: trajectory and speed measurements, cyclists’ reactions, and perception of CO-ADAS. Comparison results showed that while average lateral position differed between experiments, variations in lateral position and average speed showed no significant differences. Reaction comparison via video observation showed higher safety reactions in the on-road experiment, yet both experiments exhibited a consistent increase in safety reactions with CO-ADAS compared to reverse lights alone. Cyclists’ perceptions were also positive across both experiments. Overall, the results support simulator-based evaluation for assessing the safety impact of novel interactions like CO-ADAS on cyclists.