The effects of augmented reality head-up displays on drivers' eye scan patterns, performance, and perceptions

This paper reports on an experiment comparing Head-Up Display (HUD) and Head-Down Display (HDD) use while driving in a simulator to explore differences in glance patterns, driving performance, and user preferences. Sixteen participants completed both structured (text) and semi-structured (grid) visual search tasks on each display while following a lead vehicle in a motorway (highway) environment. Participants experienced three levels of complexity (low, medium, high) for each visual search task, with five repetitions of each level of complexity. Results suggest that the grid task was not sensitive enough to the varying visual demands, while the text task showed significant differences between displays in user preference, perceived workload, and distraction. As complexity increased, HUD use during the text task corresponded with faster performance as compared to the HDD, indicating the potential benefits when using HUDs in the driving context. Furthermore, HUD use was associated with longer sustained glances (at the respective display) as compared to the HDD, with no differences in driving performance observed. This finding suggests that AR HUDs afford longer glances without negatively affecting the longitudinal and lateral control of the vehicle – a result that has implications for how future researchers should evaluate the visual demands for AR HUDs