Cueing Car Drivers with Ultrasound Skin Stimulation.

The aim was to utilize ultrasound skin stimulation (UH) on a palm to inform the system state when interacting with mid-air hand gestures in the automotive context. Participants navigated a horizontal menu using touch, buttons, and hand gestures during simulated driving. Mid-air interaction and UH feedback design was tested in two studies. The first study proved the participants were able to perceive the menu interaction state from UH feedback, but the interaction felt inconvenient. After redesigning the mid-air gestures and the feedback for the second study, the participants rated it equally to the touch-based method, though the interaction with steering wheel buttons was still the most favorable. In conclusion UH feedback can be utilized for delivering the interactive system state to drivers, but this approach may cause additional cognitive load and should be further tested in a running car.