A UNIVERSAL PROCEDURE FOR CAPACITY DETERMINATION AT UNSIGNALIZED (PRIORITY-CONTROLLED) INTERSECTIONS

The most common type of road junction in highway transportation systems is the unsignalized (priority-controlled) intersection. This paper presents a universal procedure for calculating the capacity at unsignalized intersections. The procedure can be used for all possible stream and lane configurations (e.g., number of lanes and ranks of streams, etc.) at unsignalized intersections. A new universal capacity formula is introduced for the simplest configuration with one major stream and one minor stream. The formula is based on the idea that the time scale of the major stream can be divided into four regimes according to the relative positions between the vehicles in the major stream: (1) that of free space (no vehicle), (2) that of singe vehicle, (3) that of bunching, and (4) that of queuing. The probability of these regimes can be calculated according to the queuing theory. Therefor, the capacity of the minor stream that depends predominantly on the probability of the state that no vehicle blocks the major streams (state of free space) can also be calculated. Combining the basic idea of Heidemann and Wegmann (1997) some new explicit capacity formulae are derived considering the distributions of critical gaps, move-up times, and minimum time headways between two vehicles going in succession. Starting from this capacity formula for the simplest configuration, a universal calculation procedure for configurations with arbitrarily many streams of arbitrary ranks is derived. This procedure is constructted according to the parallel or serial configurations of the streams. Queuing theory was used to mathematically derive the present procedure. It is a generation of all of the known procedures for caluclation capacities at an unsignalized intersection. The model is calibrated and verified by measurements at roundabouts and by intensive simulations. Based on the theoretical background, the model can easily be extended to other priority systems with arbitrary priority ranks.

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• Corporate Authors:

  Elsevier

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  Kidlington, Oxford  United Kingdom  OX5 1GB
• Authors:
  • Wu, N
• Publication Date: 2001-7

Language

• English

Media Info

• Features: Figures; References;
• Pagination: p. 593-623
• Serial:
  • Transportation Research Part B: Methodological
  • Volume: 35
  • Issue Number: 6
  • Publisher: Elsevier
  • ISSN: 0191-2615
  • Serial URL: http://www.sciencedirect.com/science/journal/01912615

Subject/Index Terms

• TRT Terms: Bunching; Highway capacity; Mathematical models; Queuing; Queuing theory; Roads; Traffic distribution; Unsignalized intersections; Vehicle spacing
• Uncontrolled Terms: Distribution of critical gaps; Distribution of minimum gaps; Distribution of move-up times; Priority controlled intersection
• Subject Areas: Highways; Operations and Traffic Management; I73: Traffic Control;

Filing Info

• Accession Number: 00813917
• Record Type: Publication
• Files: TRIS, ATRI
• Created Date: Jul 9 2001 12:00AM