The transport planning process as it is usually carried out consists of a number of stages. This paper considers commonly used models for two of these stages, trip distribution and traffic assignment, and derives models combining them into a single stage. The trip distribution stage of the transport planning process is concerned with estimating the number of trips per unit time which will be made between each pair of zones in the study area. The models considered are all gravity models so that the estimated pattern of trips depends on the costs of travel between the various pairs of zones and these costs have usually been calculated from fixed costs associated with the links of the transport network. It is known, however, that the cost of travelling along a link increases with the amount of traffic using the link, and this is taken into account in the model used at the traffic assignment stage when the trip demands obtained from the trip distribution model are allocated to routes through the network. The link costs which correspond to the final estimated traffic flows obtained from the traffic assignment model are, however, not in general the same as those assumed at the trip distribution stage. In this paper this problem is overcome by combining trip distribution and traffic assignment into one stage and describing them by one model. The combined model is then reformulated as an equivalent optimization problem which is solved. /Author/ /TRRL/

  • Corporate Authors:

    Pergamon Press, Incorporated

    Maxwell House, Fairview Park
    Elmsford, NY  United States  10523
  • Authors:
    • EVANS, S P
  • Publication Date: 1976-2


  • English

Media Info

  • Features: Figures; References;
  • Pagination: p. 37-57
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00137734
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Apr 13 1977 12:00AM