The paper takes a critical look at `conventional wisdom' about public lighting of roads for drivers and pedestrians. It briefly describes orthodox quality design criteria for road lighting in Europe and North America, and challenges some assumed ideas that could lead to bad designs. European orthodoxy states that the essential concept for quality design of traffic route lighting is `luminance', but the USA has proposed new quality criteria based on visibility of objects in a road. The author argues that the visibility concept by itself is not a sufficient quality criterion for public lighting, and that luminance uniformity is insufficient for the good design of street lighting for pedestrians in urban centres. The paper makes some tentative policy suggestions for the future, by moving from the present approach, based on routine practice, narrow self-interest, and mistake, to one based on research and development, serious thought, and co-operation between disciplines. A combination of luminance and visibility concepts should produce better solutions. Systematic research is needed on such subjects as asymmetrical optical systems, lighting urban streets to protect people against crime, and appropriate performance requirements for full colour spectrum lamps.
Abstract