Operational and Safety Analysis with Mitigation Strategies for Freeway Truck Traffic in WY

The State of Wyoming road network is characterized by heavy truck traffic. In 2015, truck traffic comprised approximately 22% of Vehicle Miles Traveled (VMTs) along all routes in WY, according to the Wyoming Department of Transportation (WYDOT) Annual Traffic Report. The heaviest truck traffic exists along I-80, with about 47% truck VMTs. Trucks have significantly different physical and driving characteristics than passenger cars, especially on grades, which has impacts on operational efficiency, safety and pavement deterioration. The presence of heavy vehicles reduces the capacity of freeway segments, with the reduction being more significant along specific grades. Trucks generally decrease speed by more than 7% on upgrades as compared to their operation on level terrains, according to the Highway Capacity Manual 2010 (HCM 2010). The maximum speed that can be maintained by trucks on upgrades primarily depends on the length and steepness of the grade, as well as the truck’s weight-to-power ratio. On the other hand, the operation of passenger vehicles is much less impacted by the grade. This leads to variations in speeds between trucks and passenger vehicles, with more complex interactions between the two types. This study will look into impacts of truck traffic on selected freeway segments along I-80 in Wyoming (WY), as well as mitigation strategies to minimize negative impacts, through analyses of operational and safety implications that result from the interactions between trucks and passenger vehicles. The analysis will include the effectiveness of existing climbing lanes, and look into potential locations where the introduction of climbing lanes will be justified. The analysis will also look into other control strategies, such as different speed limits for trucks, truck lane restrictions along certain segments, and truck no-passing zones. Differential speed limits for trucks have been implemented by some US states, so this study will look into the state of practice and its effectiveness on operations and safety. Another potential issue with truck traffic on WY freeways is speed limit of 80 mph along certain segments. This raises a concern of the ability of conventional truck tires to handle such high speeds. The study will look into this issue through a review of literature and practice, as well as through crash data analysis to identify the potential relationship between truck tire failure and crash characteristics. The study will be divided into following tasks, where some of them can occur simultaneously


  • English


  • Status: Completed
  • Funding: $107069
  • Contract Numbers:


  • Sponsor Organizations:

    Research and Innovative Technology Administration

    Department of Transportation
    1200 New Jersey Avneue, SE
    Washington, DC  United States  20590
  • Managing Organizations:

    Mountain-Plains Consortium

    North Dakota State University
    P.O. Box 6050, Department 2880
    Fargo, ND  United States  58108-6050
  • Project Managers:

    Kline, Robin

  • Performing Organizations:

    Dept. of Civil and Architectural Engineering

    University of Wyoming
    Laramie, WY  United States 
  • Principal Investigators:

    Zlatkovic, Milan

    Ksaibati, Khaled

  • Start Date: 20161201
  • Expected Completion Date: 20190930
  • Actual Completion Date: 20190913
  • USDOT Program: University Transportation Centers Program
  • Source Data: MPC-519

Subject/Index Terms

Filing Info

  • Accession Number: 01618743
  • Record Type: Research project
  • Source Agency: Mountain-Plains Consortium
  • Contract Numbers: DTRT13-G-UTC38
  • Files: UTC, RiP
  • Created Date: Dec 8 2016 12:27PM