External Human–Vehicle Interaction: A User Study in the Context of a Driverless Ride-Hailing Service

Autonomous vehicles (AVs) have major potential to save lives in traffic, and when implemented in ride-hailing, they can potentially reduce traffic congestion and save labor costs. However, the majority of research in human–vehicle interactions (HVI) focuses on safe pedestrian crossing. In a ride-hailing scenario, it is important to ensure that the AV and the rider can correctly identify one another and negotiate mutual terms for the pickup. This article explores how human interaction with an AV in a ride-hailing scenario can be improved, concentrating on external interaction. A Wizard-of-Oz study was conducted in which 29 participants were asked to negotiate a pickup with an AV in a real urban traffic scenario. How aspects, such as the approaching speed of the vehicle, pickup location for the rider, as well as light panels on doors to indicate where to enter the vehicle, may affect the HVI, and trust in the AV in general, were investigated. Participants did not react differently when the vehicle approached at different speeds, and the stopping location could create confusion if the vehicle stopped after passing the rider. The findings revealed that the majority of participants failed to understand the purpose of the light panels.