Enhanced Night Visibility Series, Volume VII: Phase II—Study 5: Evaluation of Discomfort Glare During Nighttime Driving in Clear Weather

Phase II—Study 5 helped expand the knowledge of how current vision enhancement systems (VESs) affect the discomfort glare experienced by nighttime drivers. The empirical testing for this study was performed on the Smart Road. Sixty participants were involved in the study, which consisted of two data collection efforts. An 11 (VES) by 3 (Age) experimental design was used to investigate the effects of different types of VESs and driver’s age on discomfort glare. In addition, an evaluation of the Schmidt-Clausen and Bindels equation was performed to determine its predictive value in driving scenarios with oncoming glare. The results of the empirical testing suggest that halogen headlamps selected for this testing produce more discomfort glare than the high intensity discharge headlamps tested. There was also some indication that ultraviolet (UV)–A may add slightly to discomfort glare. In addition, modifications of the Schmidt-Clausen and Bindels equation may provide headlamp designers with insight into how drivers will rate discomfort glare of proposed headlamps.