Intuitive Communication Between Automated Vehicles and Vulnerable Road Users: An Experimental Study Using Virtual Reality

Effective visual communication is key to improving road safety whenever vulnerable road users (VRUs), i.e. pedestrians and cyclists, interact in daily traffic. As higher levels of automation are achieved and fully automated vehicles (AVs) become increasingly prevalent, its importance continues to grow; this is especially true for AVs above Level 3, which means the driver is `not driving' when automated driving features are engaged — even if ``the driver's seat'' is occupied. Current research shows that external human-machine interfaces (eHMI) facilitate explicit communication when AVs and VRUs interact. The three main approaches used by eHMIs are road projections, light strips, and signaling displays. This research used a VR approach (Meta Quest 3 Headset) to examine the efficiency of different types of symbols displayed by the eHMI of an AV to communicate its intentions to a VRU. Developed by Unity 6, the VR crossing scenario without a traffic light and no crosswalk was selected to evaluate the effectiveness of the selected symbols. Participant's decision times relating to vehicle intention were measured along with questionnaires to assess the clarity of vehicle intention, perception of safety and how immersive the simulation was.