The author presents a revised form of Adams' formula for determining the expected delay to a pedestrian wishing to cross a traffic stream. The original formula uses the Poisson process as a statistical model for the traffic stream. Real traffic streams, however, have a tendency to form bunches with gaps between the bunches and these features are not modelled by the Poisson process. The derivation of the new average delay formula is given in an appendix. Representative curves relating average delay and traffic flow rate are shown for different distributions of bunches and bunch size. They demonstrate that average delay is sensitive to the bunch gap structure of traffic. Importantly, the new results are sufficiently different from those given by Adams' original formula that a revision of practical traffic warrents involving pedestrian facilities seems desirable. (TRRL)

  • Availability:
  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • Cowan, R J
  • Publication Date: 1984-5

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Filing Info

  • Accession Number: 00393261
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Report/Paper Numbers: HS-037 221
  • Files: ITRD, TRIS, ATRI
  • Created Date: May 31 1985 12:00AM