Safety Effectiveness Evaluation of Road Lighting Projects in Rural Roadways

The problem of road lighting during the night hours is an influential factor on road crashes. Usually, a smaller share of trips is performed in darker hours of the night, but these hours are exposed to a large part of road crashes. The objective of this study is to determine the Crash Modification Factor for nightly crashes following the installation of lighting systems in rural roads. In this study, by comparing the data related to the frequency of crashes before and after the application of lighting equipment in the considered segments, the safety effectiveness of lighting in rural roads was measured by before-after study using the Empirical Bayesian method and the CMF for implementing the lighting supply operation was calculated. According to the data adopted from Road Maintenance and Transportation Organization, in several roadways located in three provinces of Guilan, Golestan and Semnan in 2014, light poles were installed, in which 35 segments in multi-lane roadways and 12 segments in two-way two-lane roadways were selected as treatment sites. Resulted by the EB method, the CMF value with the 95 percent significance level was estimated 0.226 for multi-lane segments and 0.445 for two-way two-lane segments. This significant effect of lighting projects was measured only for nightly crashes and in road locations where known as eligible due to the effects of adverse weather condition like the foggy mountainous roads.