Citation

Schumann J, Flannagan MJ, Sivak M, Traube EC. J. Saf. Res. 1997; 28(3): 133-146.

Copyright

(Copyright © 1997, U.S. National Safety Council, Publisher Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Reflections of the top of the dashboard seen in the windshield can result in disability glare because these reflections reduce the contrast of objects in the road scene. This phenomenon, which occurs mainly in direct sunlight, is due to the veiling luminance of the reflected sunlight being superimposed on the image of the road scene.The amount of veiling glare is influenced by the windshield rake angle and the dashboard reflectance. A field experiment under controlled sunlight conditions was performed. The independent variables included windshield rake angle, reflectance of the top of the dashboard, and subject age. The subjects were asked to detect pedestrian dummies having either high or low contrast against the background. Reaction times to the high-contrast pedestrian and misses of the low-contrast pedestrian were used as the main dependent variables.The results showed that both windshield rake angle and dashboard reflectance affected visual performance. Visual performance decreased with larger windshield rake angles and with higher dashboard-top reflectance. During those conditions, subjects needed more time to detect objects, and they had more misses in detecting low-contrast objects. The effect was particularly pronounced if a large rake angle was combined with a high dashboard reflectance, and older subjects were more affected by reductions in contrast then were younger subjects.