One design fits all? Evaluating highly automated vehicles’ communication strategies for different vehicle types and pedestrian age groups

Abstract

This research deals with the design of external Human-Machine Interfaces (eHMI) for two different vehicle types (car vs. bus) focusing on the interaction between highly automated vehicles (AV) and pedestrians of different age groups. AV need to be able to communicate with their surrounding traffic environment and their messages should be universally understood. The question that arises is how TP’s information needs may differ for different vehicle types, how this needs to be considered in the eHMI design and if different TP age groups, especially elderly, need other information for a safe and accepted interaction. However, little research addressing this question was done so far. Results of our current experimental online study (N = 229) in a shared space setting indicate an overall good implementation of the eHMI communication strategies that have been previously developed and evaluated for a car for a highly automated bus as well. In terms of a universal design this was true for all age groups. As vehicle type had a significant effect on the feeling of safety and the affective valence in interaction, eHMI might have an especially beneficial effect when interacting as a pedestrian with a large vehicle, i.e., here with a bus.