Balancing Comfort: Deceleration Rate and Environmental Impact at Crosswalks and Intersections in Automated Driving

Understanding passenger comfort in automated vehicles (AVs) is critical for advancing highly automated driving systems. This test track study was conducted in 2023 with N = 41 participants who are accustomed to German driving norms. It examined how deceleration rates and environmental factors influence passenger perceptions in two scenarios: crosswalks and blind intersections. The participants were driven by a real AV, which braked using deceleration rates of -1.5 m/s², -2.5 m/s², and -3.5 m/s². Additionally, at the crosswalk, the pedestrian visibility time, and at the intersection, the presence of an approaching vehicle was varied. The results show that passengers generally prefer lower deceleration rates but accept higher rates (-3.5 m/s²) when the pedestrian becomes visible more unexpectedly. In the intersection scenario, comfort ratings were less influenced by the presence of an approaching vehicle than by the deceleration rate, with lower rates being favoured. These findings are valuable for AV development; however, future research should explore more diverse populations to validate the study’s findings across varying traffic conditions and cultural settings. The study indicates that tailoring AV deceleration to the traffic scenarios can enhance passenger comfort. It can help AV developers define comfortable and safe perceived driving styles without compromising efficiency.