Navigating Informal Shared Spaces: AV Strategies for Joint Behavior Among Multiple Pedestrians

As automated vehicles (AVs) become integral to urban traffic, understanding multi-pedestrian interaction dynamics is crucial for ensuring safety and efficiency. This study examines how pedestrians' start positions, mutual influence, and AV communication strategies impact crossing behavior and the formation of informal shared spaces. A Virtual Reality (VR) experiment with 30 participants (15 pairs) was conducted, where two participants interacted simultaneously in the same virtual environment alongside a simulated pedestrian and an AV. Pedestrians were assigned different start positions (roadside vs. distant), and the AV employed implicit (rolling stop maneuver) and explicit (eHMI) communication strategies. Results show that distant pedestrians had significantly lower certainty and were less likely to cross in front of the AV than roadside pedestrians. However, over half engaged in joint crossing, exhibiting a significantly shorter crossing time, reinforcing the emergence of informal shared spaces. The rolling stop maneuver effectively discouraged further crossings, enhancing traffic flow but causing some confusion. These findings highlight the need to consider multi-pedestrian interaction dynamics in AV design. Further research should refine AV strategies for navigating informal shared spaces and optimizing pedestrian-AV interactions in complex urban environments.