Abstract

To be successful, automated vehicles (AVs) need to be able to manoeuvre in mixed traffic in a way that will be accepted by
road users, and maximises traffic safety and efficiency. A likely prerequisite for this success is for AVs to be able to commu-
nicate effectively with other road users in a complex traffic 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 identified 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, flashing 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 vehicle-
based behaviour, rather than communication cues from the driver. Overall, the findings 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 differences were observed. The implications of these findings are
discussed with respect to design of suitable external interfaces and communication of intent by future automated vehicles.