The objectives of this research were (1) to identify the key geometric characteristics and combinations of characteristics of road and street designs that affect accident frequencies and severity; (2) to quantify the effects of varying the key characteristics and combinations of characteristics on accident frequencies and severity; and (3) to develop a methodology that can be used by engineers in measuring the cost effectiveness of the various levels of each design element. Because only a limited number of design elements could be studied in-depth during this research, the features of pavement width, shoulder width, and shoulder surface type for rural two-lane highways were selected for quantifying their relationship to accident frequencies and severity. No significant difference was found in the accident rate between 22-ft and 24-ft pavement widths. There was a measurable difference between the 18-, 20-, and 22-ft pavements, with the wider pavements having lower accident rates. Wider shoulders and paved shoulders were also found to have lower accident rates. A cost-safety-effectiveness methodology was developed to incorporate the quantified relationships into a practical design procedure. /Author/

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    • 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. The research for this project was conducted by Roy Jorgensen Associates, Incorporated with Westat, Incorporated as a subcontractor.
  • Corporate Authors:

    Transportation Research Board

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  • Publication Date: 1978

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 237 p.
  • Serial:
    • NCHRP Report
    • Issue Number: 197
    • Publisher: Transportation Research Board
    • ISSN: 0077-5614
  • Publication flags:

    Open Access (libre)

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Filing Info

  • Accession Number: 00189840
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: Apr 12 1979 12:00AM