This report is a summary of the essential findings of a study of the safety aspects of roadside traversal. Computer simulations validated by full-scale tests were used to investigate vehicle behavior at the tree critical regions of the roadside: the hinge-point between shoulder and front slope; and the toe-of-slope, including several ditch combinations. The Highway Vehicle Object Simulation Model (HVOSM) developed at Calspan Corporation was extended and applied in the study of vehicle behavior. Assumed vehicle operating conditions included speeds up to 80 mph and encroachment angles up to 25 degrees, with and without driver steering. Driver steering was used when attempts to return to the roadway were simulated. slopes were varied from 3:1 to 10:1, and four ditch designs were included. Two coefficients of friction were used for tire-surface contact. Safety problems at high speeds were indicated for slopes steeper than about 3:1, both when a return maneuver is attempted and when a ditch is crossed. A series of charts is included for selecting traversable slope-ditch combinations. /Author/

  • Record URL:
  • Supplemental Notes:
    • See also 67 page Final Report, ISBU-0-309-02335-1, TRB/NCHRP/RFP-158, Nov. 1975. Available through NTIS, PB-247195/1ST. 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

    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Publication Date: 1975-5

Media Info

  • Media Type: Digital/other
  • Features: Figures; Tables;
  • Pagination: 7 p.
  • Serial:
  • Publication flags:

    Open Access (libre)

Subject/Index Terms

Filing Info

  • Accession Number: 00098481
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Sep 30 1976 12:00AM