THE INTERPRETATION AND USE OF SPEED/FLOW RELATIONSHIPS FOR TRANSPORT PLANNERS

Speed/flow relationships are used to describe the performance of a road and predict future journey-times which can be used to assess the effect of changes due to an improvement scheme or calculate minimum-path values and deterrence functions. The author describes steady-state, non-steady-state and average conditions of speed/flow relationships. The relative merits of each type are discussed together with possible applications. The author shows how the number of vehicles to be measured depends upon time headway, the time a platoon of vehicles takes to pass, and the measurement period. Although the shape of the speed/flow relationships depend upon how speed and flow are defined and how they are measured and aggregated, appropriate shapes are suggested and theoretically analysed. Methods of combining relationships for several roads, and difficulties experienced with junction capacities are discussed. (TRRL)

  • Availability:
  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • Lewis, P A
  • Publication Date: 1980-5

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00325203
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Report/Paper Numbers: HS-030 130
  • Files: HSL, ITRD, TRIS
  • Created Date: Apr 15 1983 12:00AM