An Investigation of Headlight Glare as Related to Lateral Separation of Vehicles

摘要

Report covers study of headlight glare in 3 parts: Compilation of current status of knowledge, field tests of disability glare, and field tests of discomfort glare. Although limited in scope, the study showed that the 94-foot lateral separation provided the most tolerable levels if both disability and discomfort glare are considered for a high beam meeting situation. Discomfort glare was the controlled factor. Low beams on other hand provided comfortable seeing under all conditions, but restricted the seeing distances such that none of the low reflectance targets were visible at a distance exceeding the safe stopping distance at 40 mph. High reflectance target could be seen in time to stop from 50 mph at lateral separation wider than 33 feet. Although increases in lateral separation appeared more effective in reducing disability glare than polarized headlighting, the value of polorized headlighting for the 6-foot lateral separation (two-land highways) cannot be ignored. (BPR Abstract)