Impact of Regulatory Hybrid Changeable Message Sign on Traffic Safety under Different Freeway Geometric Designs

The Utah Department of Transportation (UDOT) has implemented a Variable Speed Limit (VSL) zone on a section of I-80 using regulatory hybrid Changeable Message Signs (CMSs). In the current systems, the CMSs have been operated with white LED numbers on the black background. However, it has been found that the visibility of those numbers that indicate speed limits has become a problem during both winter and summer seasons. Hence, UDOT is now in the process of installing a new CMS system which replaces the color of white CMS LED by yellow. In the literature, although many recent studies have studied the impacts of CMS's visibility on improving safety, limited efforts have studied such impacts under different freeway geometric designs. By collecting historical crash locations in the VSL zones, the research team will further discuss how the new CMS can help to prevent crashes in various geometric design scenarios. By comparing the visibility of yellow-legend and white-legend CMS systems, the results will be discussed for the legend color selection for CMS. The collected safety data will be used to analyze the impacts of CMS on potential crash rate and severity using surrogate safety evaluation method.


  • English


  • Status: Active
  • Funding: $175000
  • 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:

    Mountain-Plains Consortium

    North Dakota State University
    Fargo, ND  United States  58108
  • Project Managers:

    Tolliver, Denver

  • Performing Organizations:

    Dept. of Civil and Environmental Engineering

    University of Utah
    Salt Lake City, UT  United States 
  • Principal Investigators:

    Yang, Xianfeng

  • Start Date: 20200218
  • Expected Completion Date: 20220731
  • Actual Completion Date: 0
  • USDOT Program: University Transportation Centers Program
  • Source Data: MPC-610

Subject/Index Terms

Filing Info

  • Accession Number: 01732209
  • Record Type: Research project
  • Source Agency: Mountain-Plains Consortium
  • Contract Numbers: 69A3551747108
  • Files: UTC, RIP
  • Created Date: Feb 26 2020 7:46PM