ITSC 2025 Paper Abstract

Paper FR-EA-T44.1

Wu, Yanbin (National Institute of Advanced Industrial Science and Technology), Kihara, Ken (National Institute of Advanced Industrial Science and Technology), Hashimoto, Naohisa (National Institute of AIST), Kato, Shin (National Institute of AIST)

A VR Study to Explore the Benefits and Risks of eHMI Communication Strategies for Automated Buses

Scheduled for presentation during the Regular Session "S44b-Human Factors and Human Machine Interaction in Automated Driving" (FR-EA-T44), Friday, November 21, 2025, 13:30−13:50, Currumbin

2025 IEEE 28th International Conference on Intelligent Transportation Systems (ITSC), November 18-21, 2025, Gold Coast, Australia

This information is tentative and subject to change. Compiled on October 18, 2025

Keywords Trust, Acceptance, and Public Perception of Autonomous Transportation Technologies, Autonomous Public Transport Systems and Mobility-as-a-Service (MaaS), Integration of Autonomous Vehicles with Public and Private Transport Networks

Abstract

Automated buses are being introduced worldwide to enhance public mobility. However, their unfamiliar driving behavior and lack of traditional driver communication cues may lead to safety concerns, particularly in complex traffic situations. This study investigates the potential benefits and risks of external human-machine interfaces (eHMIs) for automated buses at un-signalized intersections, where right-of-way (RoW) is often ambiguous. In a virtual reality (VR) experiment, 36 participants drove through a simulated residential area under four eHMI conditions: (1) no eHMI; (2) a status eHMI indicating the bus is operating autonomously; (3) an intention eHMI displaying the bus’s intended behavior; and (4) an instruction eHMI providing directives to other road users. Participants encountered automated buses in three types of intersection scenarios: (1) the bus had the RoW; (2) the participant’s car had the RoW; and (3) the participant had the RoW but a third vehicle violated it. Driving behavior data and subjective questionnaire responses were collected. Results revealed that both intention and instruction eHMIs reduced hesitation and increased perceived safety. However, instruction eHMI also fostered driver over-reliance on the system, leading to increased risk in the presence of non-compliant road users. These findings underscore the importance of balancing clarity and authority in eHMI design to support safe interactions while minimizing over-trust in automated buses. Overall, this study contributes to ongoing discussions on how future eHMIs can support safe, predictable interactions between automated buses and human drivers, and provides insights relevant to emerging frameworks such as ISO PAS 23735.