This study was designed to assess possible differences in the glare produced by tungsten-halogen and high-intensity discharge (HID) headlamps. Twelve subjects, three young females, three young males, three older females, and three older males, made De Boer ratings of discomfort glare for tungsten-halogen and HID lamps in a static field setup. The lighting conditions were similar to those seen while driving on a dark, two-lane road when glare from an oncoming car is encountered. Analysis of the discomfort ratings indicates that when tungsten-halogen and HID lamps produce equal discomfort glare, the tungsten-halogen lamps will produce more photopic lux at the eye of the observer. The difference is approximately 0.30 log units. This difference is in the same direction as a prediction based on laboratory results for the effect of wavelength on discomfort glare, but it is considerably larger than the prediction. This discrepancy must be resolved before it can confidently be predict how drivers will react to glare from HID headlamps in actual traffic. (A)
Abstract