The objective of the present project was to develop a simple guide for roadway lighting replacement approaches using new light source technologies to maintain visibility for safety, while reducing energy use. Several roadway types were evaluated: parkways, residential streets and rural intersections. The guide is to be suitable for a non-technical readership familiar with roadway design and safety issues, but not necessarily with lighting. A review of published literature and a survey of engineers from New York State and local transportation agencies were conducted. Based on this information as well as data on new light source technologies, a series of roadway types for inclusion in the guide was selected, and recommendations for roadway lighting system replacement were developed. Analyses of the visual efficacy produced by different lighting systems under nighttime conditions, and the performance characteristics of light emitting diode (LED) and induction fluorescent lighting systems, resulted in recommendations for replacement of high pressure sodium (HPS) lighting systems. The resulting energy savings ranged from about 7% to 50% depending upon the roadway type. Energy savings for isolated rural intersections could depend upon the level of pedestrian traffic expected. A number of new light sources that produce “whiter” light than the incumbent HPS technology used on most roadways have been developed and significantly improved in the past decade. Using these technologies in combination with recent information about driver and pedestrian vision under nighttime conditions could result in energy savings for different roadway types. A guide for replacement strategies resulting from the present project contains pointers to information about lighting policies, practices, technologies, and visual efficacy that could assist lighting decision-makers with other scenarios not discussed in the guide. (Author/publisher)
Abstract