The Highway Capacity Manual specifies procedures for evaluating intersection performance in terms of delay per vehicle. What is lacking in the current methodology is a comparable quantitative procedure for assessing the safety-based level of service (LOS) provided to motorists. The objective of the research was to develop a computational procedure for evaluating the safety-based LOS of signalized intersections based on the relative hazard of alternative intersection designs and signal timing plans. Conflict opportunity models were derived for those crossing, diverging, and stopping maneuvers associated with left-turn and rear-end accidents. Safety-based LOS criteria were then defined on the basis of distribution of conflict opportunities computed from the developed models. A case study evaluation of the LOS analysis methodology revealed that the developed safety-based criteria were not as sensitive to changes in prevailing traffic, roadway, and signal timing conditions as the traditional delay-based measure. However, the methodology did permit a quantitative assessment of the tradeoff between delay reduction and safety improvement. The results of the research are considered to be of an exploratory nature.


  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 98-104
  • Monograph Title: Traffic operations: highway capacity
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00713580
  • Record Type: Publication
  • ISBN: 0309061237
  • Files: TRIS, TRB, ATRI
  • Created Date: Nov 21 1995 12:00AM