Wind Drag Coefficients for Highway Signs and Support Structures

With increased traffic, multi-lane highways, and complex highway interchanges, highway signs play an important role in the safe operation of the nation’s transportation network. In the past, it was common to see a single large sign supported by a truss structure. In order to improve highway safety and operations, both static signs and dynamic message sign (DMS) must be used to communicate more frequently with drivers. These signs are typically larger and much heavier than the typical highway signs used in the past. Given that wind is the main load that affects these structures during their lifetime, accurate calculation of the wind loads is essential. The existing specification needed to be updated to incorporate more current and accurate information on how the wind drag coefficient varies with (1) sign geometrical parameters (e.g., sign aspect ratio, ground clearance, and sign thickness), (2) shape of signs, and (3) type of supporting structures (e.g., signs are attached to a bridge superstructure vs. an overhead sign truss). The objective of this research was to propose revisions to the wind drag coefficients in the AASHTO LRFD Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals (LRFDLTS-1). At a minimum, the research shall develop a methodology and design examples to calculate wind drag coefficients for signs and supporting structure members that are included in the LRFDLTS-1.


  • English


  • Status: Completed
  • Funding: $300000
  • Contract Numbers:

    Project 15-67

  • Sponsor Organizations:

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Abu-Hawash, Ahmad

  • Performing Organizations:

    University of Iowa, Iowa City

    102 Church Street
    Iowa City, IA  United States  52242
  • Principal Investigators:

    Constantinescu, George

  • Start Date: 20181107
  • Expected Completion Date: 20211231
  • Actual Completion Date: 0
  • Source Data: RiP Project 41635

Subject/Index Terms

Filing Info

  • Accession Number: 01634940
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 15-67
  • Files: TRB, RIP
  • Created Date: May 18 2017 12:23PM