Abstract
Under contract with the transportation and traffic engineering division of the ministry of transport a number of studies was carried out concerning the visibility of traffic control signs during nighttime. Field measurements were made on (a) the headlight intensity of a great number of cars (b) the sign luminance, and (c) the recognition distance of signs. Effects of sign illumination, sign reflectivity and fog were also considered. The overall results may serve as a valuable tool in evaluating our present regulations on the use of reflective materials and illumination. (see also B 17983).