Sensory and Cognitive Factors Affecting Automotive Head-Up Display Effectiveness

Abstract

Automotive head-up displays (HUDs) present virtual images that are focused beyond the standard instrument panel distance and that appear to be superimposed on the driver’s view of the road environment. The study assessed HUD benefits and interference potential with respect to performance of in-vehicle driving tasks and response to safety-critical roadway events under various ambient light levels by older versus younger drivers. The primary baseline against which HUD performance was evaluated was a head-down display with the same message format, content, brightness, and angular size. Performance with both visual displays was compared with auditory display (AD) performance to assess channel interference. Safety-critical road events were captured on video and were presented to observers seated in a fixed-base, part-task driving simulator. Single- and dual-task trials were presented randomly within a block of trials. Measures of response accuracy and time were obtained for in-vehicle and external targets. Eye and head movements were videotaped to assess changes in scanning behavior caused by the in-vehicle displays and external targets. The analyses revealed that performances with the HUD and the head-down display were similar, whereas performance with AD was typically more accurate and faster for both in-vehicle and external responses. HUD benefits were obtained for overall response times to external targets and responses to collision avoidance warnings. Evidence for contrast interference and “cognitive capture” with HUDs and “response capture” with AD was also obtained. Implications for HUD safety and design are discussed.