Road users rarely use explicit communication when interacting in today’s traffic: implications for automated vehicles

Abstract

To be successful, automated vehicles (AVs) need to be able to manoeuvre in mixed trafc in a way that will be accepted by road users, and maximises trafc safety and efciency. A likely prerequisite for this success is for AVs to be able to communicate efectively with other road users in a complex trafc environment. The current study, conducted as part of the European project interACT, investigates the communication strategies used by drivers and pedestrians while crossing the road at six observed locations, across three European countries. In total, 701 road user interactions were observed and annotated, using an observation protocol developed for this purpose. The observation protocols identifed 20 event categories, observed from the approaching vehicles/drivers and pedestrians. These included information about movement, looking behaviour, hand gestures, and signals used, as well as some demographic data. These observations illustrated that explicit communication techniques, such as honking, fashing headlights by drivers, or hand gestures by drivers and pedestrians, rarely occurred. This observation was consistent across sites. In addition, a follow-on questionnaire, administered to a sub-set of the observed pedestrians after crossing the road, found that when contemplating a crossing, pedestrians were more likely to use vehiclebased behaviour, rather than communication cues from the driver. Overall, the fndings suggest that vehicle-based movement information such as yielding cues are more likely to be used by pedestrians while crossing the road, compared to explicit communication cues from drivers, although some cultural diferences were observed. The implications of these fndings are discussed with respect to design of suitable external interfaces and communication of intent by future automated vehicles.