Evaluation of light-based human-machine interfaces to increase acceptance of autonomous vehicles

Fully autonomous vehicles are increasingly finding their way onto public roads. One of the main advantages of these vehicles is the free time available for non-driving related tasks. Innovative seating concepts such as swivelling front seats are designed to foster social interaction with the other passengers. However, these possibilities will only be used if these vehicles are accepted. Previous studies have shown that factors such as trust in autonomy and motion sickness have a significant influence on this acceptance. Human-machine interfaces designed to improve these factors are often conventional displays that require the occupants’ attention and gaze, limiting the freedom to perform non-driving-related tasks. To this end, recent research shows the potential of peripherally perceived motion cues to visualize driving maneuvers. In a previous laboratory study, peripheral LED panels and LED strips showed increased perceptibility and decreased distraction compared to conventional displays. To investigate to what extent these peripheral HMI concepts promote AV acceptance related factors such as trust and motion sickness during realistic driving, this study compares them in an autonomous test vehicle to a control condition without HMI. 28 participants experienced each combination of seating orientation and HMI condition on a test track. Subjects reported stronger motion sickness and lower vehicle transparency when facing rearwards. The human-machine interfaces showed selective effectiveness. They improved motion sickness and trust in some individuals, but worsened them in others, with no significant effects overall. Possible moderators for the effectiveness of the interfaces and implications for improved motion cue designs are discussed.