Actions Speak Louder: Effects of a Transforming Steering Wheel on Post-Transition Driver Performance

For partially autonomous vehicles, the user interface conveys vital information to drivers and can greatly influence how drivers behave after a transition of control from automation. Conventional interfaces that use audio and visual channels are helpful, but are limited in effectiveness. In this paper, we explore the use of a transforming steering wheel interface to assist drivers in transitions of control. We conducted two studies evaluating the effects of this system on driver performance and user experience. The first is a quantitative controlled study examining driving performance after an abrupt loss of autonomous vehicle control. The participants (N = 56) experienced a simulated driving scenario that varied the behavior of the steering wheel (transforming and nontransforming) and the transition time (2 seconds and 5 seconds). Drivers who experienced the transforming steering wheel performed significantly better than those who experienced a nontransforming steering wheel. The second study is qualitative and exploratory, where interaction experts (N = 14) evaluated the transforming steering wheel using design improvisation. The findings of these two studies suggest that a transforming steering wheel can be utilized to better assist drivers in taking back control in future autonomous vehicles.