Comparing Preferences Between Japan and Germany for External Communication of Automated Vehicles Using Bayesian Optimization

The absence of human users in automated vehicles (AVs) could require external Human-Machine Interfaces (eHMIs) to allow for communication with other vulnerable road users in uncertain scenarios. This could be, for example, regarding the right of way. Given the plethora of adjustable parameters, balancing visual and auditory elements is crucial for effective communication with other road users. With N=40 (n=20 in Germany and n=20 in Japan) participants, this study employed multi-objective Bayesian optimization to evaluate optimized eHMI designs between Japan and Germany. By comparing the Pareto front, we identify optimal design trade-offs and their differences. We also evaluate how the process is perceived between regions.