Objective: In this thesis, we explore whether augmented and diminished reality interfaces, which, respectively, add and remove information from the environment, improve a pedestrian's feeling of road crossing safety, and how this information should be conveyed to the pedestrian.
Background: Literature shows that view occlusion is a prominent cause in pedestrian collisions. The research focus is currently on vehicle technology and pedestrian warning systems. Whether aiding pedestrians with camera views from unobstructed positions helps to overcome the view occlusion problem is unclear.
Methods: Twenty-eight participants engaged in a virtual reality urban road crossing scenario, in which they took on the role of a pedestrian. The pedestrian was situated on the curb and positioned such that the view on the road was largely obstructed. An autonomous vehicle approached and drove past from the left of the pedestrian. Through a head-mounted display, the participants experienced seven prototypes: baseline (i.e., no display), see-through display, transparent car, and both a head-locked and body-locked display with and without view guidance. The order in which participants encountered the prototypes was determined by a balanced Latin square, and each interface was tested by means of six trials with a non-yielding and a yielding scenario randomly selected such that in total three non-yielding and three yielding scenarios occurred in each block. The participants were instructed to continuously indicate whether they felt safe to cross by pressing a button. The interface's acceptance, workload and preference were measured with questionnaires.
Results: The participants' perceived feeling of safety revealed improved performance for all interfaces compared to the baseline condition. For the baseline condition, in which the vulnerable road user did not have access to occlusion-free information, the perceived feeling of safety was the lowest on average and decreased the earliest in the autonomous vehicle approaching phase, as well as scoring the lowest rating on acceptance. The see-through display and the transparent car interfaces, which used a combination of augmented and diminished reality properties to convey the information in a world-anchored manner to the pedestrians, achieved a higher acceptance and perceived feeling of safety than the head-locked and body-locked display interfaces.
Conclusion: A vulnerable road user's perceived feeling of safety can be increased by means of camera views from unobstructed positions to help overcome the view occlusion problem in common road crossing scenarios. This study's findings suggest a positive effect for diminished reality techniques for pedestrians, and future research could examine this technology further in more demanding scenarios.