SAFETY ON THE ROAD AT NIGHT: (4) LIGHTS ON THE ROAD

The author claims that good road lighting more than pays for itself in reducing accidents, but dangers are still too high. Continuing research is needed to ensure that all practicable assistance is given to the driver to enable him to see and understand. The clear illumination of the kerbs and footways, plus the revelation of the environment and some guidance about the route ahead are just as important as uniform surface brightness. The contained contrasts of the road surface depend much more on the character rather than the amount of light. Lighting must also promote rapid response to movement. The author discusses the use of headlamps in streets served by street lighting. He concludes that the optical performance of a road installation is reduced by the use of vehicle headlamps, and that the optical range of headlamps is reduced by street lighting. Recent improvements in road lighting have not been matched by vehicle headlamps because of the cost and requirements of the stylists. For abstracts of parts 1, 2 and 3, see IRRD abstracts nos. 222951-3.