The objectives of this project were to: a) analyze the safety benefits associated with roadway lighting; b) determine the design of the lighting installation necessary to provide an adequate level of lighting; c) investigate how lighting affects the driver and the roadway’s surrounding environment; d) review the economic correlation between effective lighting and cost savings for the State; e) provide input for updating the current section on street and highway lighting in the Traffic Guidance Manual; and f) analyze crash data to identify nighttime high crash locations. The procedure involved a literature search, a survey of states, crash data analysis, and collection of illumination data.
The survey of states found that most states used information from either “An Informational Guide for Roadway Lighting” by AASHTO or “American Standard Practice for Roadway Lighting (ANSI/IESNA RP-8-00)” as a basis for their warrants and design of highway lighting. A procedure was developed to identify spots or sections that have a critical number or rate of nighttime crashes. An interactive nighttime critical rate analysis program was developed. Crashes at spots and intersections having a high number or rate of nighttime crashes were reviewed. A large number of the locations identified as having a high nighttime crash rate are rural locations where the nighttime crashes can be addressed with improved delineation (pavement markings and signage). The illumination data show that the AASHTO guidelines can be met with a limited number of properly located luminaries. For example, one luminary placed across from the single approach at a “T-intersection” or two luminaries on diagonal quadrants of a “cross-intersection” (adjacent to the side street stop approach) were found to meet the guidelines if properly located.
Available at: http://works.bepress.com/eric_green/54/