Lag Acceptance Analysis for a Rural Unsignalized Intersection

More than 30% of all vehicle crashes in the US occur at intersections; these crashes result in nearly 9,000 annual fatalities, or approximately 25% of all traffic fatalities. Moreover, these crashes lead to approximately 1.5 million annual injuries, accounting for approximately 50% of all traffic injuries. AASHTO recognized the significance of rural unsignalized intersection crashes in its 2005 Strategic Highway Safety Plan, and identified the development and use of new technologies as a key initiative to address the problem of intersection crashes. Before a new technology to reduce intersection crashes can be deployed, driver behavior leading to these crashes must be better understood. Described herein are lag acceptance distributions measured by a traffic surveillance system which measures and records the state of the intersection at 10 Hz. Sensitivity of accepted lag distributions to traffic density, time of day, and time waiting for a lag is described. An understanding of these lag acceptance distributions can be used as the basis for the timing of the alerts and warnings issued to drivers waiting to enter or cross the major road traffic stream. Comparisons of lag acceptance at the test intersection to critical gaps and acceptable gaps in major-road traffic implied by current AASHTO policy are provided. Distributions of lags accepted at the intersection show that a significant number of drivers accept lags smaller than those described by critical gap methods and AASHTO policy. An analysis of these smaller than expected lags is also presented.

  • Corporate Authors:

    Transportation Research Board

    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Authors:
    • Alexander, Lee
    • Cheng, Pi-Ming
    • Donath, Max
    • Gorjestani, Alec
    • Menon, Arvind
    • Newstrom, Bryan
    • Shankwitz, Craig
    • Ward, Nicholas J
    • Starr, Ray
  • Conference:
  • Date: 2007


  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 14p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01044776
  • Record Type: Publication
  • Report/Paper Numbers: 07-2204
  • Files: BTRIS, TRIS, TRB
  • Created Date: Feb 8 2007 6:53PM