Comparative Study on Differences in User Reaction by Visual and Auditory Signals for Multimodal eHMI Design

Abstract

Autonomous vehicles (AV) from level 4 to level 5 will drive in traffic in a few years. The interaction between AVs and other road users could be supported by external human-machine interfaces (eHMIs). eHMIs have been suggested in various formats so far. In this study, an experiment was carried out to compare differences between visual and auditory signals. It assumed specific situations in which the AV is close to a pedestrian to assess the types of response, reaction speed, and warning. It was conducted with the Wizard of Oz technique, and individual experimental data from18 participants were measured and analyzed. Research showed that a combination of a visual and auditory interface is most effective in understanding information. Also, auditory signals are advantageous in cognitive response in most cases, and such warnings were evaluated more highly. Therefore, it is required to consider an appropriate multimodal design when pedestrians need to pay attention. © 2021, Springer Nature Switzerland AG.