Designing a Light-Based Extension of the Vehicle Environment for Motion Sickness Mitigation

As autonomous vehicles (AVs) continue to enter the market, new possibilities emerge for passengers to take advantage of their time while being driven. However, due to the loss of vehicle control and the shifting of the passenger's gaze from the road to objects in the vehicle interior, the risk of motion sickness increases. This can reduce the acceptance of AVs. Light-based motion cues could reduce the sensory mismatch between expected and experienced motion and thus mitigate motion sickness. Studies on the effectiveness of these cues have thus far focused on visualizing either longitudinal or lateral dynamics, with moderate success. The present work investigates the design of light cues to adequately visualize both AVs' longitudinal and lateral dynamics to their passengers. To this end, expert workshops were conducted involving 15 professionals from the automotive lighting industry, who evaluated different variants of the light-based interface in a Cave Automatic Virtual Environment (CAVETM). The cues consisted of light dots mimicking the optic flow generated by the vehicle's surroundings. The cues' velocity scaling in relation to the actual vehicle velocity, the visualization of turning maneuvers, and the temporal offset between light cues and driving maneuvers were manipulated. The experts assessed each variant via questionnaires. The visualizations were then discussed in groups and a preferred variant was agreed upon. The results show that logarithmic as opposed to linear velocity scaling was favored. Indicating turning maneuvers in addition to the visualization of lateral acceleration while cornering was preferred by most experts. Cues that are played at the same time as the corresponding driving maneuvers were preferred over predictive cues. Implications for the design of light-based interfaces for motion sickness mitigation can be derived. Simultaneous maneuver visualization with adequate velocity scaling and comprehensible turn coding is a promising approach for successful motion sickness mitigation in AVs.