UI Design of eHMI of Autonomous Vehicles

In recent years there has been an increasing trend for autonomous vehicles (AV) to feature an external human-machine interface (eHMI). This study investigates the usability issues of an eHMI composed of light bands and displays that need to communicate with multiple types of road users and how designers intend to map all this and cover all these needs in one user interface design. In the first experiment, a physical prototype was built in a conventional car and shown to 18 participants. In the second experiment, the same eHMI concept, with improvements made from the first usability test, was shown to 500 participants in a digital prototype. In both tests, the usability of eHMIs, as well as the overall acceptance level of AVs before and after reviewing the eHMI concept, were evaluated. The results indicate that our eHMI designs positively influenced overall acceptance because they have clearer driving information and sense the visibility of the AV system. In close traffic negotiations when AVs communicate on the basis of what they sense and perceive, people felt uncomfortable with AVs perceiving them, which will be an increasingly important issue in the design conversation between fully autonomous AVs and general road users.