The relative visibility of two tasks which are typical of those encountered in the nighttime driving situation was explored using the visual Task Evaluator (VTE) measurement technique. The tasks were illuminated with either high or low headlight beams. An opposing vehicle was located at one of several longitudinal separations with the same beam configuration as that of the observer's to simulate a single approaching vehicle at one of four different median widths. Disability glare measurement were made with a prichard photometer and the overall visibility evaluated through an analytical procedure. The two tasks studied were (a) a red retro-reflector on the rear of an lighted, black car, parked 500 ft from the observer on the right shoulder, and (b) a section of standard pavement stripe, 200ft. ahead on the right-hand pavement edge.
Abstract