Skip Navigation

Mid-America Transportation Center

Evaluation of Alternative Geometric Designs on Highway Corridors - Case Study of J Turns

Final Report
click to download report


Researchers

  • Principal Investigator: Praveen Edara (edarap@missouri.edu 573-882-1900)
  • Co-Principal Investigator: Carlos Sun (csun@missouri.edu 573-884-6330)
  • Project Status
    Complete
    About this Project
    Brief Project Description & Background
    Alternative geometric designs such as J-turns, double crossover interchanges and continuous flow intersections have the potential to improve safety and traffic flow on freeways and arterials. The evaluation of such designs will provide information on their effectiveness and guidance for their proper deployment. Missouri DOT has recently started using J-turn design as a corridor safety treatment on rural high-speed roads. In this project, we propose to evaluate the safety and operational benefits of this J-turn deployment. The analysis will focus on several safety and operational performance measures, including conflicts, actual crash statistics, driver confusion measures, heavy vehicle maneuverability, gap acceptance, and travel time measures. The study findings assist Missouri and other Midwest states with new knowledge on the benefits of J-turn design and guidance on when to consider deploying J-turns as a corridor level safety treatment.
    Research Objective
    The research objective is to evaluate the safety and operational benefits of a corridor deployment of J-turns using a variety of performance measures.
    Potential Benefits
    This project supports three key focus areas of MATC and USDOT - enhancing safety, capacity, and design. By reducing the number of conflict points, many alternative intersection designs are safer than their conventional counterparts. Crash data has also supported this finding for designs such as Median U-turns, J-turns, Jughandles, continuous flow intersections. Operational benefits such as reduced delays and increased capacities have also been reported for alternative designs. In this study, the safety and operational benefits of a corridor-level deployment of one alternative design namely the J-turn will be assessed.
    Abstract
    Alternative geometric designs such as J-turns, double crossover interchanges and continuous flow intersections have the potential to improve safety and traffic flow on freeways and arterials. The evaluation of such designs will provide information on their effectiveness and guidance for their proper deployment.
    Project Amount
    $ 24,229