Model Development of U-turn Capacity Using Simulation and Empirical Approaches

In this study, both empirical and simulation approaches were used to estimate capacity of U-turn movement at median openings of divided arterials. The empirical approach using regression analysis was adopted to estimate the best form of the predictive equation for the U-turn capacity and investigate the effect of different relevant factors that might affect the estimated capacity. Simulation approach was used also to calculate capacity on the basis of the U-SIM model; this model represents the traffic performance at U-turn median openings and calculates the number of turning vehicles with respect to a different conflicting traffic stream. The results of both approaches were compared and presented in this study. A linear model was also recommended as a relationship between the average total delay of the Uturning vehicles and the conflicting traffic flo