Adaptive curve headlights swivel with driver steering input and have been linked with a reduction in insurance collision claims and improved visual performance for drivers who use them. The current test track study assessed whether the glare experienced by 20 study participants from a production vehicle with adaptive high-intensity discharge (HID) headlights in low beam mode differed from the glare from fixed (non-swiveling) HID and fixed halogen low beam headlights. Participants also rated one fixed high beam headlight system as a benchmark for excessive glare. Participants in a stationary vehicle rated glare from each vehicle’s headlights, using the DeBoer visual discomfort response scale (1 = unbearable to 9 = barely noticeable), as a test driver drove towards them from five roadway approaches. An illuminance meter near participants’ heads recorded oncoming light levels. Participants rated the fixed halogen low beam condition as less glaring than the adaptive and fixed HID low beam conditions, and there was no significant difference in subjective ratings between the two HID low beam conditions. Collapsing across roadway approaches, the mean ratings for the fixed halogen, adaptive HID, and fixed HID low beam conditions were 7.4, 6.8, and 6.5, respectively, all “satisfactory” levels of glare. The differences in ratings between the fixed high beam condition and the low beam conditions were quite large. Differences between subjective ratings were supported by illuminance data. Thus, while the adaptive HID low beam system introduced more glare than the fixed halogen low beam condition, it did not present more glare than the fixed HID low beam condition, and differences among the three low beam systems appear minor, relative to their differences from the fixed high beam condition. (Author/publisher)
Abstract