Updating and Implementing the Grade Severity Rating System for Wyoming Mountain Passes: Evaluating the Safety Effectiveness of Downgrade Warning Signs (Volume 2)

Truck safety on mountain passes presents a major challenge to most highway agencies in western United States. Large trucks are known to be disproportionately affected on severe downgrades which characterize mountain passes in comparison to other vehicle classes due to large sizes and heavy loads. The Wyoming Department of Transportation in an effort to reduce crash risks on Wyoming mountain passes has among other measures installed warning signs on steep grades in the state. The main purpose of this study is to develop recommendations of the best warning system on Wyoming mountain passes based on an evaluation of the impact of warning signs on truck crashes. Hazardous downgrades in the state were identified and data was collected to build a crash database. Several analyses were then conducted to evaluate the impact of advance downgrade warning signs on truck crashes. The analyses included propensity score matching, negative binomial modeling, and ranking of sites and a hotspot analysis of warning sign placement. The potential use of intelligent transportation systems in reducing downgrade truck crashes was assessed as well. The results of the analyses indicate that the various downgrade warning signs are effective in preventing downgrade crashes on mountain passes.

• Record URL:
  • https://rosap.ntl.bts.gov/view/dot/54402
• Corporate Authors:

  University of Wyoming

  Dept. of Civil and Architectural Engineering
  1000 E. University Avenue
  Laramie, WY  United States  82071

  Wyoming Department of Transportation

  5300 Bishop Boulevard
  Cheyenne, WY  United States  82009-3340
• Authors:
  • Moomen, Milhan
  • 0000-0001-8324-7540
  • Raja, Mustaffa Ngah
  • 0000-0001-7480-5133
  • Apronti, Dick
  • 0000-0002-2072-2030
  • Rezapour, Mohammed Mahdi
  • 0000-0002-3368-722X
  • Ksaibati, Khaled
  • 0000-0002-9241-1792
• Publication Date: 2018-12

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Maps; Photos; References; Tables;
• Pagination: 175p

Subject/Index Terms

• TRT Terms: Countermeasures; Heavy duty trucks; High risk locations; Intelligent transportation systems; Road downgrades; Truck crashes; Trucking safety; Warning signs
• Identifier Terms: Wyoming Department of Transportation
• Geographic Terms: Wyoming
• Subject Areas: Data and Information Technology; Highways; Motor Carriers; Safety and Human Factors;

Filing Info

• Accession Number: 01765713
• Record Type: Publication
• Report/Paper Numbers: WY-1901F (Vol 2)
• Files: NTL, TRIS, ATRI, STATEDOT
• Created Date: Feb 22 2021 10:22AM