Understanding how Time-to-Arrival and Vehicle Speed Influence Pedestrian Crossing Behavior at Unsignalized Intersections Through a Virtual Reality Experiment

Understanding pedestrian behavior is crucial for improving road safety especially considering the advent of autonomous vehicles (AVs) and AD/ADAS systems. This study employs a Virtual Reality (VR) simulator to investigate pedestrian crossing decisions under varying vehicle speeds (20, 30, and 40 km/h) and Time-to-Arrival (TTA) intervals (3, 4, 5, and 6 seconds). Key behavioral metrics, including crossing percentage, gap acceptance, safety margin, and time to crossing decision, were analyzed. The results indicate that longer TTAs significantly increase crossing likelihood, as pedestrians perceive greater safety. Although higher vehicle speeds also correlate with increased crossing percentages, this effect may stem from the experimental design, where higher speeds resulted in greater physical distances to the vehicle. Statistical analysis confirmed that TTA strongly influences pedestrian safety metrics, particularly safety margin and time to crossing decision, while vehicle speed had a limited effect. Qualitative feedback highlighted challenges in speed estimation, particularly at greater distances, which likely influenced crossing decisions. Participants also reported minor limitations related to VR immersion, such as the absence of auditory cues and concerns about the headset cable. These factors may have influenced crossing behavior, underscoring the importance of refining VR environments for pedestrian studies.