The aim of street lighting authorities and lighting engineers is to light trafficways in their charge to the best of their ability and means, a desire modulated by the embarrassing multitude of light sources available for the purpose. In this article an attempt is made to assess those factors which bear upon the selection of a light source for use on main roads. Such an appraisement must necessarily be limited to those factors affecting the economics of street lighting even though other factors such as daylight appearance and colour rendering also have to be taken into account. Accordingly only basic costs are considered - it being the prerogative of the providers of street lighting to decide what other costs shall be met on the score of amenity and harmony. (A)
Abstract