Do I really have to know everything? – iHMI communication strategies in complex situations for a HAV

Abstract

Automated driving functionalities in vehicles are increasing year by year. A major challenge for highly automated vehicles (HAV; SAE 4) is the detection of relevant objects in a driving situation which sets the basis for suitable driving manoeuvers. However, this information can also be used to design the interaction between the HAV and its user. Communicating the automation’s awareness is crucial for creating understanding of the current situation, establishing transparency, and ensuring both trust and user acceptance. Research suggested a LED light-band as suitable internal Human-Machine Interface (iHMI) communicating this information. The current study investigated iHMI communication concepts for complex driving scenarios displaying multiple road users to reduce the user’s subjective uncertainty. In an online study (N=154) participants experienced drives in a HAV that had to consider three other interacting road users (two closer and a third, more distant road user). It was investigated, if all present road users need to be addressed on the iHMI to reduce subjective uncertainty of the user. Results showed that a perception-based communication concept leads to lower uncertainty ratings compared to a static one or no iHMI. No difference was found for displaying all vs. only the two road users near to the HAV.