The conventional measure of benefit in transport models has been given by the "rule-of-half". Its inaccuracy is usually acceptable for those transport improvements causing only marginal changes to transport costs. Exact measures are available for appropriate forms of model, and may be used where the rule of half becomes unreliable. They may be interpreted as accessibility benefits or as shadow-price changes, as well as changes in consumers' surplus. Land-use changes give rise to altered constraints on trip-totals; it is shown that these are analogous to non-marginal transport cost changes. Their effects may thus be evaluated by extensions of exact methods. The rule-of-half may also be extended for this purpose but will yield unreliable estimates. (Author/TRRL)

  • Corporate Authors:

    Department for Transport, England

    Great Minster House, 76 Marsham Street
    London,   England  SW1P 4DR
  • Authors:
    • Day, MJL
  • Publication Date: 1979-6

Media Info

  • Features: Figures; References;
  • Pagination: 54 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00322125
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Report/Paper Numbers: No. 10 Monograph
  • Files: ITRD, TRIS
  • Created Date: Apr 15 1981 12:00AM