COST-EFFECTIVENESS OF GUARDRAIL-BRIDGERAIL TRANSITION IMPROVEMENTS: DOUBLE W-BEAM VERSUS DECREASED POST SPACING

A study of the performance characteristics of two guardrail-bridgerail transition systems is reported. The two systems were the American Association of Highway and Transportation Officials (AASHTO) stiff-post system and the Nebraska Department of Roads (NDR) "double W-beam" system. The AASHTO system provides larger-sized posts on reduced spacings, whereas the NDR system uses another length of guardrail alongside the face of the existing guardrail with uniform 1.01-m (6-ft 3-in) post spacings. The NDR system eliminates the difficulty of increasing the stiffness of existing systems because of the concrete bridge abutments and/or wing walls that restrict the placement of additional posts on reduced spacings. The objective of the study, which was limited in scope, was to use the BARRIER VII computer program to compare the cost-effectiveness of the two systems. The study considered the effects of impacts with the guardrail transitions by two different-sized automobiles under all possible combinations of speed and angle. The findings show that a reasonable doubt exists as to the cost-effectiveness of the AASHTO system under a wide range of impact conditions. Specifically, the stiff-post system produced more injury-type accidents and resulted in larger exit angles, which increased concern about secondary collisions with other vehicles. The structural adequacy of the guardrail-bridgerail connection in both systems was the single most important design element. (Authors)

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1980/769/769-006.pdf
• Record URL:
  https://scholar.google.com/scholar_lookup?title=COST-EFFECTIVENESS+OF+GUARDRAIL-BRIDGERAIL+TRANSITION+IMPROVEMENTS%3A+DOUBLE+W-BEAM+VERSUS+DECREASED+POST+SPACING&author=E.+Post&author=P.+McCoy&author=T.+Wipf&author=R.+Ruby&publication_year=1980
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• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Safety Appurtenances. 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
• Authors:
  • Post, Edward R
  • McCoy, Patrick T
  • Wipf, Terry J
  • Ruby, Richard J
• Conference:
  • 59th Annual Meeting of the Transportation Research Board
  • Location: Washington District of Columbia, United States
  • Date: 1980-1-21 to 1980-1-25
• Publication Date: 1980

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 37-43
• Monograph Title: Roadside hazards, traffic barriers, and safety appurtenances
• Serial:
  • Transportation Research Record
  • Issue Number: 769
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Bridge abutments; Bridge railings; Concrete structures; Cost effectiveness; Crash severity; Guardrail transition sections; Gullies; Highway safety; Impact tests; Improvements; Injuries; Performance; Safety equipment; Stiffness
• Old TRIS Terms: Gullying
• Subject Areas: Design; Highways; Research; Safety and Human Factors; I85: Safety Devices used in Transport Infrastructure;

Filing Info

• Accession Number: 00331275
• Record Type: Publication
• ISBN: 0309031133
• Files: TRIS, TRB
• Created Date: Oct 28 1981 12:00AM