Citation

Christie AW. Highw. Res. Board bull. 1954; 89: 21-37.

Copyright

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

DOI

unavailable

PMID

unavailable

Abstract

A practical method of dealing with the reflection of a pavement surface is described. A reduced range of data, presented in a single family of curves, is found to be sufficient for calculating the luminance (brightness) in the important regions of a street-lighting installation within an accuracy of about 15 percent. The experimental methods adopted at the road research laboratory to obtain the necessary data are described, measurements are made outdoors on the actual pavement surfaces. Reflection characteristics for three typical dry british pavement surfaces are presented. In addition, contours of equal luminance in the bright patches obtained on these surfaces under standard conditions are shown in perspective drawing. Standard contours are also given for one of the smoother types of pavement surface formerly employed, and for a fine-textured surface with a high resistance to skidding. The coarse-textured surface and even the finer sandpaper finishes, which are being adopted as a means of improving the resistance of the pavement ot skidding, cut down the reflection of obliquely incident light. This face may account for the movement away from high-angle-beam lighting towards medium-angle-beam lighting which is evident in great britian today. The effect of texture depth on reflection when the surface is wet is briefly examined.