Citation

Stone JA, Lauer AR. Highw. Res. Board bull. 1954; 89: 62-67.

Copyright

(Copyright © 1954, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

Various studies have been made of the effect of filters, tinted glasses and windshields as they affect seeing at night. On the average all results have shown a deleterious effect although individual observers sometimes may show a slight improvement. These variations in direction are undoubtedly chance errors as might be expected from any large number of measurements. Lauer investigated the possibility of beneficial effects from certain wave-length bright headlights at night but that losses in visual increment of nonlinear relationship between increased transmission of light and legibility of letters as measured by the clason acuity meter. More recently, studies by others have supported these earlier findings in greater or lesser degree. In other words, the hypothesis that some types of filters which lower light transmissions may increase acuity at night is rejected. /author/ luminance appear to be sufficiently great.