Impact of Geometric Conditions on Wyoming’s Rural Crashes

The main objective of this research is to evaluate the impact of geometric conditions on the safety of Wyoming rural roads. The data used in this research was obtained from the Wyoming crash database. The data was summarized in three functional rural roadway classifications: interstate, state highways, and local roads. Determining the risk associated with various geometric conditions is paramount for improving the current Wyoming State Highway Safety Plan (WSHSP) which was adopted in September of 2006. Two periods of four years, “before” and “after” September 2006, were analyzed in this paper. A Weighted Severity Index (WSI) value was calculated for every category of combinations of geometric characteristics to determine if any geometric conditions resulted in more severe crashes. The analysis was divided into two phases. The first phase used the WSI to compare the total crash percentage against the Equivalent Property Damage Only (EPDO) percentage for every geometric combination. The findings indicated that four roadway types had the most significant proportion of severe crashes: curved-level and curved-downhill geometric combinations on both state highway and local roads. The second phase analyzed the four roadway types identified in the first phase of research to determine the proportion of different types of severe crashes. Only roadway departure crashes were analyzed in this phase. The findings indicated that a majority of roadway departure crashes on all four identified roadway types involve rollovers, which have the highest crash severity. The findings of this study will help in revising the comprehensive safety plan for Wyoming to reduce crashes on rural roads statewide.

• Record URL:
  • http://onlinepubs.trb.org/onlinepubs/conferences/2011/RSS/2/Coulter,Z.pdf
• 
• Supplemental Notes:
  • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Corporate Authors:

  Transportation Research Board

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• Authors:
  • Coulter, Zebulun C
  • Ksaibati, Khaled
• Conference:
  • 3rd International Conference on Road Safety and Simulation
  • Location: Indianapolis Indiana, United States
  • Date: 2011-9-14 to 2011-9-16
• Publication Date: 2011

Language

• English

Media Info

• Media Type: Digital/other
• Features: References; Tables;
• Pagination: 21p
• Monograph Title: 3rd International Conference on Road Safety and Simulation

Subject/Index Terms

• TRT Terms: Crash data; Crash severity; Geometric design; High risk locations; Ran off road crashes; Rollover crashes; Rural highways
• Uncontrolled Terms: Equivalent property damage only
• Geographic Terms: Wyoming
• Subject Areas: Highways; Safety and Human Factors; I82: Accidents and Transport Infrastructure;

Filing Info

• Accession Number: 01504306
• Record Type: Publication
• Files: TRIS, TRB, ATRI
• Created Date: Jan 24 2014 2:29PM