The objectives of the study were to examine the safety consequences from the installation of U-turns at signalized intersections in Kentucky and to develop a set of guidelines for using this alternative in the future. The literature review indicated that the use of U-turns is very effective in reducing delays as well as crash rates. The most efficient configuration is that of stop-controlled median U-turns. An analysis of the crash data shows that the U-turn design in the Kentucky locations did not result in a large number of crashes involving U-turning vehicles. Also, at the Somerset location where the design eliminated median crossovers between intersections, there was a decrease in total crashes. Potential factors that could affect the implementation of U-turns at intersections were examined. Using delay time as a measure of effectiveness, it was concluded that the presence of the U-turn enhances the operation of the corridor, most likely due to the more efficient processing of vehicles at the downstream intersection. The study recommends that U-turns should be considered for corridors with peak volumes greater than 1,500 vph or for cases where the expected total turn volume is greater than 20% of the total approach volume.
Samenvatting