Visibility under night driving conditions

Abstract

Field and laboratory data have been re-analyzed from a number of studies relevant to night driving visibility. For unlit, open road conditions it has been shown that the visibilities of tail lights, disc objects and pedestrian dummies can be related by a single luminance-visual area characteristic. A set of luminance increment-visual area (Δ L, A) night driving characteristics has been established for predicting visibility under varying conditions of background and glare veiling luminances. For small angles of glare (<100') it was found necessary to use a modified form of the Hartmann-Moser veiling luminance formula LEV = KEθ-3.5. Predictions have been made of the required reflective performance of road studs located under road lighting. A number of topics are discussed with regard to the derivation and application of the proposed (Δ L, A) night driving characteristics.