Abstract
An investigation has been carried out to determine the intensity of a head lamp which will be adequately conspicuous on urban traffic routes lit by street lighting without being too bright. The intensity requirements were largely independent of observer attributes, the luminance of the road surface and its surrounds and the number and movement of the vehicles. However, the results suggest that conspicuity and brightness are different attributes of a light. The optimum lighting solution appears to be a town beam, based on dimming, the present dipped headlight, giving a straight ahead intensity of 80 cd.