Where to Look? A Review of External Autonomous Vehicle Signaling to Increase Pedestrian Safety

Autonomous vehicles are becoming increasingly popular in society. Removing manual drivers from the vehicle-pedestrian interaction presents new challenges on how to explicitly communicate information to other road users. Many external human-machine interface (eHMI) designs have been proposed including text, icon, and light bar arrangements mounted on various locations of the vehicle. This scoping review examines the effects of different eHMI designs, locations, contexts, and other characteristics and how they affect pedestrian crossing decisions to improve safety. Results indicate that text-based visual eHMI displays offer the best pedestrian understanding while light bar displays have the quickest perception and reaction time.