A method for assessing the visibility benefits of roadway lighting

Photometrically accurate lighting software and a model of visual performance were used to evaluate realistic roadway lighting and driver scenarios. A great deal of data, both virtual photometric quantities and values of relative visual performance, were generated. A method for simplifying these data was developed to create practical insights about the value of different fixed roadway lighting systems. In particular, it was concluded that it is important to illuminate both high- and low-speed intersections, to provide high illumination for older drivers on high-speed roadways with intersections, and perhaps to incorporate refined photosensor-based control of lighting in highly developed areas. The approach used here enables officials responsible for public cost and public safety to make more sophisticated and rational decisions about roadway lighting.