U-turn lanes are commonly provided at at-grade diamond interchanges with frontage roads to reduce delays for U-turning traffic and for the interchange as a whole; however, there are currently many unknowns related to their design, operation, and use. Researchers of this study assessed the existing practice of U-turn implementation by evaluating operations of U-turn lanes at 25 diamond interchanges in Texas through field data collection and simulation analysis. Researchers determined the performance and limitations of U-turn lanes under various geometric and operational conditions, identified and investigated several factors affecting U-turn lane use, and determined the anticipated effectiveness of proposed solutions to U-turn operational issues. This paper provides implementable guidelines for designing and operating U-turn lanes at diamond interchanges. Among the ten countermeasures studied in this paper, closing nearby driveways, adding acceleration lane for U-turn departures, and separating U-turn departures from conflicting traffic using pylons were found to be effective solutions to improve U-turn operations.


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    Title :

    Operational Evaluation of U-Turns at At-Grade Signalized Diamond Interchanges


    Additional title:

    Transportation Research Record: Journal of the Transportation Research Board


    Contributors:


    Publication date :

    2019-04-04




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English