On face value: a ghost driver field study investigating interactions between pedestrians and a driverless vehicle with anthropomorphic displays

In a novel, on-road study, using a 'Ghost Driver' to emulate an automated vehicle (AV), we captured over 10 hours of video (n = 520) and 64 survey responses documenting the behaviour and attitudes of pedestrians in response to the AV. Three prototype external human-machine interfaces (eHMIs) described the AV's behaviour, awareness and intention using elements of anthropomorphism: High (human face), Low (car motif), Abstract (partial representation of human features that lacked precise visual reference); these were evaluated against a (no eHMI) baseline. Despite many pedestrians reporting that they still relied on vehicular cues to negotiate their crossing, there was a desire/expectation expressed for explicit communication with future AVs. High and Low anthropomorphism eHMIs received the most positive responses for clarity, confidence and trust, with High also attracting significantly more/longer glances and the highest preference rating. In contrast, Abstract was considered least clear and subsequently invited the lowest confidence and trust ratings.