Scaling up Automated Vehicles' eHMI Communication Designs to Interactions with Multiple Pedestrians - Putting eHMIs to the Test

To ensure safety in future mixed traffic, automated vehicles (AV) will have to interact in an understandable way with other, more vulnerable road users (VRU). Current research has shown positive effects on the AV-VRU interaction for external human-machine interfaces (eHMI). The paper presents preliminary results of an online video study, focusing on the evaluation of different eHMI designs in situations with multiple pedestrians. Three eHMI communication designs using a 360 degrees LED-light band and different combinations of additional pedestrians' positionings were analyzed. The main goal of this study was to investigate how the communication designs were interpreted in situations with multiple pedestrians and whether negative effects may arise through their presence. Preliminary results showed that participants crossed the street more often, experienced more certainty in their decision, and felt more addressed if they were interacting with an AV with intention-based communication strategy compared to a static eHMI or no eHMI.