The Role of Auditory eHMI: How Does It Influence Communication between Highly Automated Vehicles and Pedestrians?

Effective communication between automated vehicles (HAVs) and pedestrians is essential for road safety, particularly in the context of sustainable urban environments. This study investigated the impact of visual and auditory eHMIs influence psychological factors and behavioral responses in pedestrian-vehicle interactions, with a particular focus on the synchronization of auditory eHMIs with vehicle kinematics. Through two video-based experiments, we assessed the effects of different eHMI configurations on pedestrians’ willingness to cross, trust, perceived safety, and intent comprehension. The results indicate that multimodal eHMIs significantly enhance perceived safety and intent understanding, while their impact on trust and willingness to cross remains limited. Notably, synchronized auditory eHMIs further im-proved perceived safety in yielding scenarios, suggesting that aligning auditory cues with vehicle motion can strengthen pedestrians’ sense of security. These findings provide empirical evidence supporting the integration of multimodal eHMIs in HAV design, emphasizing the importance of dynamic auditory signals in shaping pedestrian perceptions. By underscoring the necessity of designing eHMIs that not only convey vehicle intent effectively but al-so align with pedestrian expectations in dynamic traffic environments, this study provides insights for designing safer and more intuitive automated vehicle systems.