Evaluation of Cost-effective Alternative Designs for Rural Expressway Intersections

Despite numerous studies demonstrating the effectiveness of Restricted Crossing U-Turn (RCUT) intersection design, its implementation remains uneven and close to zero in some large states, including California. This research provides a comprehensive framework to estimate the operational and safety performance of future RCUT designs in California. The framework is demonstrated for five intersections located on high-speed rural expressways in Caltrans districts 5 and 6. The operational evaluation relies on microscopic simulation models of existing two-way stop control (TWSC) and alternate RCUT designs used to estimate network-wide performance measures. Two approaches were demonstrated for future safety estimation; first, an HSM-prescribed Empirical Bayes approach that uses Safety Performance Function (SPF) predictions combined with the crash history of the site. For typical applications, Empirical Bayes estimates may be combined with crash modification factors (CMFs) for RCUT found in the literature. This approach remains the preferred option for safety estimation. However, for geometrically constrained locations where atypical RCUT designs need to be evaluated, a surrogate measure-based method that uses trajectory data from the simulation model is described. The framework demonstrated here may be used by agencies to estimate the future benefits of the first-time application of treatments that have been successful elsewhere. Based on the results, a reduction of the number of high-severity (fatal and injury) crashes is expected by constructing an RCUT intersection; however, the number of low-severity (no injury) crashes might be increased. Regarding traffic operation, no significant difference was identified between RCUT designs and the existing intersection designs at four of the five intersections evaluated. One of the intersections did result in travel time savings due to moderately high left-turn traffic from the minor road.

• Record URL:
  https://ctedd.uta.edu/wp-content/uploads/2021/08/MolanEtAl_RCut_FinalReport_CTEDD_2020.pdf
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/57457
• Supplemental Notes:
  • This document was sponsored by the U.S. Department of Transportation, University Transportation Centers Program.
• Corporate Authors:

  California Polytechnic State University, San Luis Obispo

  Department of Civil and Environmental Engineering, 1 Grand Avenue
  San Luis Obispo, CA  United States  93407

  Center for Transportation Equity, Decisions & Dollars (CTEDD)

  University of Texas at Arlington
  Arlington, TX  United States  76019

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590
• Authors:
  • Molan, Amirarsalan M
  • Howard, Jonathan
  • Islam, Mouyid
  • Pande, Anurag
• Publication Date: 2021-1-31

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 70p

Subject/Index Terms

• TRT Terms: Alternatives analysis; Crash rates; Highway design; Rural highways; Traffic simulation; U turns
• Geographic Terms: California
• Subject Areas: Design; Highways; Operations and Traffic Management; Planning and Forecasting; Safety and Human Factors;

Filing Info

• Accession Number: 01781938
• Record Type: Publication
• Report/Paper Numbers: CTEDD 019-08
• Contract Numbers: 69A3551747134
• Files: UTC, NTL, TRIS, ATRI, USDOT
• Created Date: Sep 20 2021 2:52PM