Design friction in autonomous drive—exploring transitions between autonomous and manual drive in non-urgent situations

In the ongoing turn to automation, the growing trend towards the design of conditionally and highly automated vehicles (C/HAV) is evident. In a CAV, the driver no longer needs to partake in the driving. However, the vehicle might send a takeover request (TOR) when the CAV’s system reaches its operational boundaries, i.e. a call for a transition from autonomous to manual drive. Previous research on TORs has focused on the context of urgent situations, e.g. hazards and unpredictable events. Furthermore, it has been noted that drivers’ situation awareness (SA) deteriorates after being in autonomous drive. However, less is known about TORs in non-urgent situations. Motivated by this need, the study explores how design friction can serve as a guiding concept for transferring control between autonomous and manual drive in non-urgent situations to increase situation awareness. Design friction is defined as elements of interactions that steer attention and guides the driver to take informed decisions. The work resulted in prototypes that leveraged design friction as part of a takeover sequence. The proposed design was empirically evaluated in a fixed-base medium-fidelity driving simulator. The results indicated that the level of friction might have been too extensive, as some annoyance was expressed. However, participants claimed to feel calm and aware of their surroundings at the moment of regaining control of the vehicle. This suggests that design friction is a promising tool for guiding concept design to enhance transitions from autonomous to manual drive.