Visualizing implicit eHMI for autonomous vehicles.

Autonomous vehicles' (AVs) interactions with pedestrians remain an ongoing uncertainty. Studies claim the need for explicit external human-machine interfaces (eHMI) such as lights to replace the lack of eye contact with and explicit gestures from drivers. To further explore this area, we conducted a naturalistic field study using the Ghostdriver protocol to explore how pedestrians react to a simulated driverless vehicle stopping at a crosswalk in real traffic on real roads. All pedestrians crossed in front of the vehicle with little hesitation, even though we did not signal anything beyond the vehicle's stopping motion. A few were surprised at the vehicle's novelty, however most paid little attention to its autonomous appearance. The video includes demonstrative examples of the kinds of reactions we observed, which we hope will further a dialogue on the role of eHMI in AV-pedestrian interactions.