Clear and Unambiguous HMIs : final report

In 2023, TNO investigated the development of a quantitative measurement scale to assess Automated Driving Systems (ADS) Human-Machine Interfaces (HMIs) within the project User Centered Design of Automated Driving System Human Machine Interfaces. In this project TNO developed a questionnaire to measure if the information provided to the driver by ADS (Automated Driving Systems) or DCAS (Driver Control Assistance Systems) is experienced as clear and unambiguous (see Development of a measurement scale to assess Automated Driving System HMIs)

The objective of the research presented here is to assess the validity and reliability of the questionnaire on realistic HMI designs and for user groups with and without experience with ADS or Driver Control Assistance Systems (DCAS). In contrast to the previous project, where the questionnaire was tested only on transitioning HMIs, it is now validated on both transitioning and static HMIs. Automation levels covered by the HMIs in this study include manual driving, L2 hands-on and L2 hands-off, where the driver must remain attentive, as well as partial driving automation (L3) where the driver can disengage but must be ready to take over. Additionally, the previous project only involved good and bad HMI designs. In the current project, it was investigated whether the questionnaire can distinguish among designs with poor, intermediate, and good quality. Furthermore, in this project, the questionnaire was tested in a driving simulator instead of a desktop environment. The simulator brings us a step closer to applying the method during actual driving.