Evaluating the Effectiveness of Lightening Installation in Reducing Overnight Crashes of Rural Roads

In this research, the effectiveness of installing night lighting in rural roads was evaluated. To this end, a number of rural roads of Ilam province have been selected. Two axes have been selected as the counter group and two axes as the comparison group. Crash data of four years has been collected. The collected data is analyzed according to before and after study with comparison group for studying crash reduction and benefit/cost method for economic analysis. For accurately estimating the effectiveness, the predicted crashes on improved and comparison sites were used. These predictions were done using the prediction model of crashes in rural two-way roads, and then the results were calibrated for local conditions using the crash modification factor related to lighting installation and also the model calibration method. By applying different stages of the method, the results show a 28% reduction in the frequency of overnight crashes after lighting installation. The statistical significance test indicates the accuracy of the result at 90% confidence level. The results demonstrate an acceptable effectiveness of lighting installation in reduce overnight crashes. The results of the economic evaluation of lighting installation in this study indicate that lighting installing has been successful in improving safety. The ratio of the benefit to the total cost of lighting installing on two counter sites is 1700 to 1. This value indicates that the benefits gained in Rial value are much higher than the annual costs of lighting installation during a 15-year period and about 1700 times.