Assessing and Addressing Deficiencies in the HCM Weaving Segment Analyses

The Highway Capacity Manual 6th Edition (HCM6) provides methods for the evaluation of freeway segments and freeway facilities including weaving segments. Weaving segments are often critical components of freeway facilities because they can act as bottlenecks. Recent research has questioned the validity of the HCM6 weaving analysis methodology. The main objectives of this research project were to identify, document, and address the major deficiencies in the current HCM6 weaving method through improved modeling of key procedures and their calibration. The research team conducted a literature review to identify and document deficiencies in the procedure. Next, the team collected field data and obtained previously collected data at weaves and developed a new framework for evaluating operations at freeway weaves. This new framework uses the basic segment freeway model and a speed impedance factor that represents the weaving turbulence, which proved to be simpler and more accurate than the models in the HCM6. A model was developed for Type A or ramp weaves, which predicts the average speed of the weaving segment directly without using intermediate models to predict the number of lane changes. It was concluded that the HCM6 model tended to underestimate the speed within the weaving section compared to field data. A sensitivity analysis showed that the new model can predict the speed and capacity for ramp weaves reasonably well.


  • English


  • Status: Completed
  • Funding: $130000
  • Contract Numbers:


  • Sponsor Organizations:

    Office of the Assistant Secretary for Research and Technology

    University Transportation Centers Program
    Department of Transportation
    Washington, DC  United States  20590
  • Managing Organizations:

    Southeastern Transportation Research, Innovation, Development and Education Center (STRIDE)

    University of Florida
    365 Weil Hall
    Gainesville, FL  United States  32611
  • Project Managers:

    Tucker-Thomas, Dawn

  • Performing Organizations:

    North Carolina State University

    Institute for Transportation Research and Education
    909 Capability Drive, Suite 3600
    Raleigh, NC  United States  27606

    University of Florida Transportation Institute

    P.O. Box 116580
    Gainesville, FL  United States  32611
  • Principal Investigators:

    Rouphail, Nagui

  • Start Date: 20180801
  • Expected Completion Date: 20200831
  • Actual Completion Date: 20210314
  • USDOT Program: University Transportation Centers Program

Subject/Index Terms

Filing Info

  • Accession Number: 01680029
  • Record Type: Research project
  • Source Agency: Southeastern Transportation Research, Innovation, Development and Education Center (STRIDE)
  • Contract Numbers: 69A3551747104
  • Files: UTC, RIP
  • Created Date: Sep 4 2018 11:28AM