The objective of this study was to evaluate the discomfort and disability glare produced by oncoming headlamps with varying beam intensity and distribution. Oncoming headlamps can be visually discomforting and disabling to drivers at night. In recent years, high intensity discharge (HID) headlamps have raised some concern because of their increased light output and brighter appearance than traditional halogen headlamps. During the discomfort glare portion of this study, participants drove an experimental vehicle at 32 km/h (20 mi/h) past stationary glare headlamps. They were asked to rate their overall discomfort using the subjective deBoer scale. The disability glare portion involved drivers detecting a static pedestrian either near the road centerline or near the road edgeline while approaching different sets of glare headlamps. It was hypothesized that there would be significant differences in detection distance, illuminance at the driver’s eye, and discomfort glare rating across the different glare headlamp, pedestrian position, adaptation level, and participant age combinations. The main effect of glare headlamp was the only significant factor in the analysis for discomfort glare. The main effects of age, glare headlamp, and pedestrian location were all significant in the analysis for the disability glare portion. In addition, the interaction of pedestrian location and glare headlamp was significant. Overall, headlamps that had higher subjective discomfort ratings were the same lamps that had worse objective disability measures. The conclusions of this research will be valuable to the consumer as well as the manufacturers and designers of future headlamps in revealing how glare can affect drivers on the road at night. This information can help guide new designs to maximize forward visibility while minimizing glare. (Author/publisher)
Samenvatting