This research was undertaken to evaluate the cost-benefits of arterial highway lighting treatments in terms of traffic safety and energy usage. The results have shown that total night-time dry weather accidents are inversely related to visibility, higher visibility resulting in fewer accidents. Areas with high population densities have a much higher rate than low density areas and CBD areas have a much higher rate than other area types. Regression equations have been developed which predict dry night-time accident history based on population density, area type and visibility. The results have also shown that more cost-beneficial lighting systems CNA be designed using HPS rather than Mercury luminaires although it is normally possible to use either source to obtain systems with benefit-cost ratio greater than 1. When visibility and accident reduction potential are the main constraints, optimum designs tend to use 400 HPS luminaries; when cost and energy use are the main constraints, 150 HPS luminaires tend to be optimum. In addition to this Final Report, a Design Guide (FHWA-RD-77-38( has been prepared to assist potential users in conducting cost-benefit analyses of lighting changes at specific locations. (Author)
Abstract