Improving the experience in the pedestrian's interaction with an autonomous vehicle: An ergonomic comparison of external HMI

The number of studies on autonomous vehicles has increased over recent years. Many of these studies have indicated the importance of an external Human-Machine Interface of communication (eHMI) on autonomous vehicles to indicate their intentions to other road users. Using an experimental design, we compared three eHMIs coupled to three road infrastructures to observe pedestrians' crossing behavior and collect their feelings about different vehicle types. Our results showed that the eHMIs influence the pedestrians' decision to cross the street, confirming the importance of setting up eHMIs. The proportion of pedestrians who crossed in front of the autonomous vehicles was more significant for vehicles equipped with an eHMI than vehicles without an eHMI. In 10% of cases, pedestrians used circumvention strategies rather than crossing in front of a vehicle without an eHMI. This behavior was more often observed when there was no protected infrastructure. Finally, while our objective data failed to indicate whether a specific eHMI is better accepted than another, the subjective data on the participants' preferences provided some promising ideas for further studies and the eHMI final implementation. •A virtual environment study was conducted among pedestrians to observe their street-crossing comportments.•Pedestrians cross the street behind a vehicle without an eHMI more often than one with an eHMI.•The road infrastructure has an impact on the crossing pedestrians' behaviors.•Participants preferred LED light strips and pictograms over threads of diodes.