Standard against nonstandard urban intersection nighttime traffic safety evaluation using cross-sectional method

This paper investigates the safety benefit of standard versus nonstandard lighting ones using the cross-sectional method to develop associate crash modification factor (CMF). Forty urban intersections were involved in this study. Initially, a proper number of explanatory variables determined using the Pearson correlation measure. After that, a negative binomial regression method was employed as a safety performance function to estimate the expected frequency of crashes. Using Omnibus test of model validity, the applied safety performance function was approved. According to predefined thresholds, the 40 studied sites were binary classified into two groups: standard versus nonstandard sites. The crash modification factor was then estimated as the division of the expected number of nighttime crash frequencies of lighted intersections to unlighted ones resulting in CMF equal to 0.785, implying 23.5% safety benefit of urban intersection standard lighting provision.