Take-over requests during highly automated driving: How should they be presented and under what conditions?

Even with highly automated driving, there will exist the occasional need for a human driver to resume control. The design of take-over requests (TOR) and the driving scenario upon their presentation are factors that can be expected to determine the effective resumption of vehicle control. We conducted a driving simulator study in the laboratory that examined how either an abstract or skeuomorphic TOR design influenced driving resumption, given different conditions of road curvature and time headway. We found that drivers react faster and more accurately when experiencing a skeuomorphic visualisation of a TOR prompt compared to an abstract interface, especially when there is less time headway. Moreover, participants reported subjective preferences for the skeuomorphic TOR design and considered them to be more intuitively comprehensible. Furthermore, more accurate TOR responses were found when TORS of lateral control were presented before longitudinal control. Based on these results, we formulated five conclusions relating to the design of take-over requests. These conclusions should be validated in more realistic settings. However, in the future, they could be the basis for more research developing design guidelines that could create safe and reliable communications between drivers and vehicles. (C) 2019 Elsevier Ltd. All rights reserved.