Author Description

It has been reported that nationwide, about one quarter of the roadway travel commonly occurs after dark and half of the roadway traffic fatalities occurred at night. The nighttime traffic crash fatality rate is about three times the daytime traffic crash fatality rate. The problem may become worse at unlit or poorly lit critical roadway safety spots such as interchange, intersections, and railroad and highway crossing, particularly in adverse weather conditions. This study was conducted to investigate the lighting effects on crashes at Indiana intersections. The analysis of Indiana nighttime crash data to identify the contributing factors was conducted. The study intersection sites were selected based on crash frequencies and crash severities. Before and after field light tests were conducted to verify in-service light performance, including illuminance distribution and uniformity ratio. AGi32 simulation was also performed for three selected intersections to compare with field test results. In addition, the long term performance of demonstration luminaires at the I-74 & US 231 interchange was tracked and documented. This activity provides a better understanding of maintenance issues, cycles, and costs. Surveys to both State Highway Agencies (SHAs) and communities were conducted in order to identify perceptions from SHAs and the public toward lighting improvement. The community survey included questions such as the public attitudes to intersection lighting, effectiveness of lighting, visibility improvement, and safety improvement. To quantify safety effects of lighting at intersections, crash modification factors (CMFs) were developed by using two methodologies: before-and-after analysis and cross-sectional statistical analysis. The developed CMFs could be used to justify roadway lighting projects. Life Cycle Cost Analysis (LCCA) was conducted to determine the best lighting solution given a real project scenario. The analysis considered initial (luminaire and instal