Traffic accidents are the ideal measure of safety for a highway location. But attempts to estimate the relative safety of a highway location are usually fraught with the problems associated with the unreliability of accident records and the time required to wait for adequate sample sizes. For these reasons, the Traffic Conflicts Technique (TCT) was developed as a surrogate measure in an attempt to objectively measure the accident potential of a highway location without having to wait for an accident history to evolve. The TCT was originally developed by the General Motors Research Laboratories (GMR) in 1967. It was conceived as a systematic method of observing and measuring accident potential. Conflicts were defined as the occurrence of evasive vehicular actions and characterized by braking and/or weaving maneuvers. Based on the positive results of a large investigative study by the Federal Highway Administration (FHWA), reported by Baker in 1971, the TCT has gained popularity as an evaluative tool. The Washington State Department of Highways is using the TCT as a diagnostic tool to determine appropriate countermeasures at high-accident locations. Others have suggested the technique as a priority ranking criterion for programming the order for the implementation of spot improvements. And, the FHWA has incorporated the TCT as a research tool into several recent problem statements in its contract research program. This report critically evaluates the state-of-the-art of the TCT and the results of recent attempts to develop a rigorous experimental design using traffic conflicts as the basic response variable to measure the effectiveness of access control techniques at commercial driveways.

  • Record URL:
  • Supplemental Notes:
    • Sponsored by FHWA and DOT. Administration, Office of Research and Development. Available NTIS, PB-261072/3ST.
  • Corporate Authors:

    Midwest Research Institute

    425 Volker Boulevard
    Kansas City, MO  United States  64110-2299
  • Authors:
    • Glennon, J C
    • Thorson, B A
  • Publication Date: 1975-12

Media Info

  • Features: References; Tables;
  • Pagination: 46 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00131993
  • Record Type: Publication
  • Source Agency: Highway Safety Research Institute
  • Report/Paper Numbers: FHWA-RD-76- 88 Final Rpt.
  • Contract Numbers: DOT-FH-11-8121
  • Files: NTL, TRIS
  • Created Date: Jun 5 1977 12:00AM