Exploring Optimal eHMI Display Location for Various Vehicle Types: A VR User Study

External human-machine interfaces (eHMI) are anticipated to enhance pedestrian interactions with automated vehicles (AVs) and increase social acceptance. While previous studies have focused on enhancing eHMI design by exploring various modalities and color preferences, identifying the optimal eHMI location on vehicles remains a significant challenge. Existing research has begun to explore different display locations for eHMI, but a thorough examination of the factors related to vehicle type, such as vehicle size, that influence pedestrian preferences is still lacking. Therefore, we conducted a Virtual Reality user study to assess pedestrian reactions to various AVs equipped with eHMI in different positions. Our findings reveal that larger vehicles are perceived as less safe by pedestrians, yet their increased visibility from a distance, due to longer light bands, impacts pedestrians' crossing decisions. Additionally, the location and height of the eHMI relative to eye level are crucial, with inappropriate positioning leading to diminished effectiveness.