Your Turn or My Turn?: Design of a Human-Machine Interface for Conditional Automation

Cooperative Conditionally Automated Driving (CAD) systems pose new challenges to the development of human-machine interfaces (HMI). The system's current status and intentions must be communicated unambiguously to ensure safe driver-system interaction and acceptance. This topic is becoming increasingly important as advanced automated driving functions are expected to carry out tactical and strategical driving maneuvers. Within the current study, an HMI for CAD was designed and evaluated by a sample of human factors experts (N=6). The participants passed seven interaction scenarios in which they either had to take over control or let the system execute a maneuver. Driving task responsibility was explicitly communicated by the HMI (e.g., by coloring and semantic text information). Quantitative and qualitative system usability was examined during and after the drive. Results pointed towards a very good overall usability and acceptance. Except for one case, interactions went according to the system's intention. Suggested design improvements were implemented.