Optimal Location of U-Turn Median Openings on Roadways

Abstract

Many state and local transportation agencies have considered using U-turns as alternatives to direct left turns from driveways or side streets. Median designs are used that prohibit left turns onto the facility and mid-block U-turn median openings to accommodate diverted left turns from side streets or driveways. The location of these U-turn median openings has a great impact on the operations of U-turns. Traffic operations (weaving and delay) for right turns followed by U-turn movements on urban or suburban multilane roadways were analyzed. A working model was developed to guide the location of U-turn median openings by minimizing the average delay for U-turn movements. A case study demonstrates the operational and safety benefits of optimal U-turn median opening location.