OPERATIONAL EFFECTS OF SECONDARY STOPPING AND RECOVERY AREAS

This effort to determine how to measure and evaluate the effects of the geometric elements in the operation of vehicles encroaching in median and border areas, considers the frequency and nature of vehicle encroachments on roadside areas, and the standards of measure. Reference is made to research, and the variables to be considered in overall encroachment frequency, spot frequency and nature of encroachments are listed. Studies in Illinois led to the conclusion that a 30 ft. width of obstacle free median with mild cross slopes is the absolute minimum requirement for the relatively safe stopping or control of vehicles encroaching on medians at rural operating speeds. Roadside obstacles and their relation to encroaching vehicles are discussed as well as warrants for the installation of median barriers and guardrails. Because the accident frequency associated with any one obstacle is so small, the probablistic approach is the best method to identify hazardous roadside situations on a large scale. It is recommended that 2 standards be used to measure and evaluate a section of highway with respect to operational effects of secondary stopping and recovery areas. The first standard is encroachments per mile per year. The ratio, encroachments per accident should be used as a measure of the "forgiveness" of the secondary stopping and recovery area.

• Record URL:
  https://onlinepubs.trb.org/Onlinepubs/trcircular/182/182.pdf
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00978515
• 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

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Publication Date: 1976-12

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 12 p.
• Serial:
  • Transportation Research Circular
  • Issue Number: 182
  • Publisher: Transportation Research Board
  • ISSN: 0097-8515

Subject/Index Terms

• TRT Terms: Geometric design; Guardrails; Highway safety; Measurement; Median barriers; Medians; Right of way (Land); Roadside; Roadside structures; Standards; Stopping; Vehicles; Warrants (Traffic control devices)
• Uncontrolled Terms: Recovery
• Old TRIS Terms: Encroachments
• Subject Areas: Highways; Operations and Traffic Management; Vehicles and Equipment;

Filing Info

• Accession Number: 00148112
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Feb 16 1977 12:00AM