Citation

Pritchard BS, Blackwell HR. Highw. Res. Board bull. 1958; 191.

Copyright

(Copyright © 1958, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

The light transmission and polar scattering properties of natural and artificial fogs have been measured. Since polarization effects in scatter are very large, considerable effort has been devoted to obtaining complete polarization information. These data will be used to design and evaluate improved lighting systems for use on the highway in fog. For each proposed system, the luminances and contrasts of objects as seen through the fog can now be computed. The scattering curves have already suggested some improvements which might be made, and these have been viewed in a 3:1 scale model simulator at the pennsylvania state university and in a 25:1 simulator at the university of michigan. These tests have demonstrated that visibility in fog can be improved by changing the candlepower distribution of street lights to avoid forward scatter, by employing vehicle fog lights which are mounted as far as possible away from the driver's line-of-vision, and by increasing the candlepower of taillights. Quantitative information about the improvements to be gained by these and other changes will be obtained in an improved simulator now under construction.