Passing Sight Distance Criteria

The design criteria for minimum passing sight distance (PSD) for two-lane highways in AASHTO's 2001 A Policy on Geometric Design of Highways and Streets (the "Green Book") have remained virtually unchanged since they were incorporated into the 1954 edition of the policy. The 1954 policy used criteria based on a summary report of extensive field observations of passing maneuvers made during 1938 to 1941 by Prisk and published in Proceedings HRB Volume 21. Surveys conducted in 1971 and 1978 found that AASHTO values for PSD were conservative, except at passing vehicle speeds above 65 mph, and these values continued to be used in the 1984, 1990, 1994, and 2001 editions. Findings from other studies have been presented in various forums discussing PSD subsequent to 2001, but the PSD values in the Green Book remain unchanged. The vehicle fleet, operating conditions, and characteristics of the driver have changed considerably over the past 50 years, but the current PSD criteria do not take these changes into account. Furthermore, the operational criteria in the FHWA Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD) and the design criteria in the Green Book result in different minimum passing sight distance values for similar conditions, and there has been considerable discussion on whether these differences should be rationalized or reconciled. This research is needed to provide passing sight distances consistent with today's conditions and to resolve inconsistencies between existing criteria. The results will be valuable for highway design and operations nationwide and will be considered for incorporation in future editions of both the Green Book and the MUTCD. The objectives of this study are to evaluate the design and operational criteria for determining minimum passing sight distance and to modify or develop new PSD criteria for the Green Book and the MUTCD.


  • English


  • Status: Completed
  • Funding: $300000.00
  • Contract Numbers:

    Project 15-26

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Hedges, Christopher

  • Performing Organizations:

    Midwest Research Institute

    425 Volker Boulevard
    Kansas City, MO  United States  64110-2299
  • Principal Investigators:

    Harwood, Douglas

  • Start Date: 20040601
  • Expected Completion Date: 0
  • Actual Completion Date: 20070930
  • Source Data: RiP Project 9001

Subject/Index Terms

Filing Info

  • Accession Number: 01460823
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 15-26
  • Files: RiP, USDOT
  • Created Date: Jan 3 2013 1:33PM