In-Service Performance Evaluation of Iowa’s Sloped End Treatments

Sloped end treatments (SETs) were historically developed as low-cost, low-maintenance end treatments for rigid features like concrete barriers and bridge rails. Crash testing indicated that sloped end treatments are associated with significant instability for impacting vehicles, but their historical crash performance was not known. An in-service performance evaluation (ISPE) was performed to evaluate vehicle crashes with sloped end treatments in Iowa between 2008 and 2017. Researchers generated a geographic inventory of 658 sloped end treatment locations, reviewed crash narratives and scene diagrams for crashes near these sloped end treatments, and calculated an estimated crash rate and crash cost for these sloped end treatments. A total of 30 SET-related crashes were identified, resulting in one fatal crash and one severe injury crash. Eighteen of these crashes climbed the SET feature and seven crashes were associated with vehicle rollover, with eight unknown crash outcomes. The estimated sloped end treatment average crash cost was approximately $178,260. For comparison, crash costs for other fixed objects in the same vicinity as sloped end treatments, typically associated with roads with higher speed limits, averaged $67,449 per crash. Benefit cost was calculated for replacing select groups of sloped end treatments with various crash cushions. Nineteen of the crashes occurred on a total of seven bridges, indicating most impacts were in “black spot” locations. Researchers recommended prioritization of removal and replacement of some sloped end treatments based on crash history.

Language

  • English

Media Info

  • Media Type: Web
  • Edition: 1
  • Features: References;
  • Pagination: pp 789-804
  • Monograph Title: Advances in Road Infrastructure and Mobility: Proceedings of the 18th International Road Federation World Meeting & Exhibition, Dubai 2021
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 01870657
  • Record Type: Publication
  • ISBN: 9783030798000
  • Files: TRIS
  • Created Date: Jan 24 2023 9:28AM