Transport (and land use), by its nature requires that long term plans be created. The information on which a plan will be based must therefore be a forecast of equally long term. Examples of forecasts likely to be needed are of population, prosperity and fuel price. It is not possible to obtain accurate forecasts for as far into the future as one needs to plan transport. A choice therefore remains: one can make a "central" forecast and specify uncomfortably large confidence intervals on key variables. As an alternative, which is advocated in this report, one can specify precisely a number of alternative futures, each with a measure of likelihood attached. Each can be called a scenario. This report describes how scenarios can be used for long term planning of transport. The aim has been to produce a method which though imperfect, is acceptable for dealing with the formidable task of planning in the face of uncertainty. We describe how to obtain a suitable number of scenarios, how they should be used in the process of creating several long term plans, and how to arrive at one long term plan. The importance of robustness and flexibility in plans is emphasized. The report remains as far as possible at a general level, though it is necessary to indicate in principle the effect of a scenario approach on aspects such as evaluation. /Author/TRRL/

  • Corporate Authors:

    National Institute for Transport & Rd Res S Af

    P.O. Box 395
    Pretoria 0001, Transvaal,   South Africa 
  • Authors:
    • Royce, N J
  • Publication Date: 1978-2


  • English

Media Info

  • Features: Figures;
  • Pagination: 22 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00189619
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Tech Rpt RT/3/78
  • Files: ITRD, TRIS
  • Created Date: May 11 1979 12:00AM