Minimal risk maneuver communication in highly automated shuttles via internal human-machine interfaces using media richness for user-centered interface design

Abstract

Highly automated shuttles (HAV; SAE 4) replace the human driver through sophisticated automation systems. This means that users will have no one to communicate directly with in case of problematic situations. One possible countermeasure could be increasing system transparency, by a multi-layered internal Human-Machine Interface (iHMI), providing information to shuttle users. However, it is still unclear how information should be communicated to users to ensure good user experience during minimal risk maneuvers (MRM). We conducted an experimental study in virtual reality, facilitating the media richness theory to address this issue providing a multi-layered iHMI consisting of a visual representation of upcoming steps during MRMs accompanied by an avatar surrogating the media richness of face-to-face communication with a shuttle driver. Using a block-design, the participants experienced three versions of the iHMI in three situations each, either a solely visual interface with the problem-solving steps, the visual interface including loudspeaker announcements, or the visual interface in addition to the avatar giving the announcements. After each situation, participants were asked to answer several short questionnaires regarding their experience. Results provide insights into how media-richness of iHMIs can foster passenger experience in HAVs and, therefore, facilitate user adoption of these future mobility services.