Bike to the Future: Designing Holistic Autonomous Vehicle-Cyclist Interfaces

AV-cyclist interaction research has focused on individual interfaces, e.g., eHMIs or AR glasses. However, cyclists using multiple independent interfaces could receive redundant or contradictory messages, causing unsafe encounters. We introduce the \emph{Holistic AV-Cyclist Interface}: multiple displays facilitating communication together to ensure safe road sharing. We used participatory design with cyclists and HCI researchers (N=12) to develop holistic interfaces around an actual vehicle equipped with an eHMI. Participants created holistic interfaces communicating blindspot warnings and AV intent and accommodating two-way communication, e.g. through on-bike directional indicators. They mostly placed interfaces on the bicycle handlebars and cycling accessories, e.g. helmet. Holistic interfaces could overcome design challenges: they can be multimodal, facilitate communication between AVs and multiple cyclists, and work in varying weather/visibility conditions. We categorised participant designs into a taxonomy and developed a novel holistic interface based on our findings. Our results are important for the safe integration of AVs into traffic.