Exploring External Human Machine Interface Design for Autonomous Vehicle to Pedestrian Communication: Insights from Discussions and Drawing Sessions

Abstract: The development of an effective external Human-Machine Interface (eHMI) for autonomous vehicles (AVs) is crucial for safe interaction with their environment. However, most current eHMI concepts are designed for one-to-one interaction and fail to consider complex interactions with multiple road users. To address this need, we conducted two focus group discussions and drawing sessions to gather participants’ feedback about AVs communication in mixed traffic situations and to come up with design ideas for eHMIs. In focus groups, eleven participants expressed mixed opinions about AVs, some of which were optimistic about their potential benefits, while others expressed skepticism about their accuracy and safety. All of the participants expressed a desire for clear communication from AVs, including information about the AV's mode, intention, surroundings detection, and advising. The participants also discussed the criteria for designing effective eHMIs, emphasizing the importance of simplicity, clarity, visibility, and not directing messages to specific individuals. In drawing sessions, participants generated 31 designs, with symbol modality being the most common. Multiple modalities were used more frequently in the designs, with text and symbol being the most common combination. Radiator grilles and windshields were the most popular display locations. Advice to pedestrians was the most frequently provided information type in the designs. Participants preferred using fewer information types in their designs, with most designs utilizing just one or two information types per display. Overall, this work provides valuable insights and guidance for the design, standardization, regulation, and overall development of eHMIs that is currently ongoing.

Keywords: autonomous vehicles, mixed traffic situations, communication solutions, vehicle-to-pedestrian (V2P) communications, external HMIs, design ideas

DOI: 10.54941/ahfe1004469

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