Evaluating the Presence of Bus Rapid Transit (BRT) lines on frequency of Crashes in Urban highways (Case Study: Resalat Highway in Tehran)

Safety of urban highways is one of the most important issues in traffic management of big cities, which is typically influenced by several factors including implementing specific lanes and stations of public transit. This study evaluates the safety effects of implementing a Bus Rapid Transit (BRT) lane on frequency of crashes in urban highways. In this study, 14 treatment sites were selected for a before-after study and 40 reference sites in terms of geometric and traffic similarities were selected for development of Safety Performance Functions (SPFs). Crash data for three years before and three years after implementing the BRT lane were used to evaluate the effectiveness by the means of Empirical Bayesian (EB) method. Only mid-block crashes were involved in the analysis. The Crash Modification Factor (CMF) was estimated 0.87 at a 95% confidence interval that reduces the total number of crashes By 12.58%. The Empirical Bayesian (EB) method because of eliminating the Regression-To-Mean (RTM) effect can precisely estimate the number of crashes and effective factors in reducing them. The EB method estimated the expected frequency of crashes using both predicted and observed frequencies. The range of crash reduction varied between 1.25 to 65.6 percent.