Sign brightness in relation to position, distance and reflectorization.

There is need for quantitative comparison of the brightnesses of different sign materials in various situations on the highway. This paper describes a method for calculating the brightness of a reflective material, for a given distance and placement. The method is applied to investigate the effects of such factors as sign position with respect to the pavement, type of reflective material, type of headlamp, type of vehicle, and vertical and horizontal curves. Relationships of these factors to sign legibility and their implications for signing practice are discussed. /author/.