IDEAS home Printed from
   My bibliography  Save this article

Travel Time - Variable or Constant?


  • David Metz


Empirically, travel time averaged across a population is invariant at close to one hour per person per day. Nevertheless, standard transport analysis treats travel time as a variable, scoring the value of time savings in cost-benefit analysis of proposed new infrastructure, and minimising generalised travel time in transport modelling. This paper argues that the invariance of travel time needs to be explained, and that such an explanation might involve a marginal approach to travel time, as well as the possibility of there being an intrinsic utility to travel. These concepts are consistent with economic principles but not with the current practice of transport economics. It is further argued that the benefits of transport system improvement are to be found in the additional access afforded, not in notional travel time savings; and that conventional transport models that pay no regard to the invariance of aggregate travel time may mislead. It is suggested that in transport analysis, aggregate travel time should be treated as a constant, not a variable. © 2004 LSE and the University of Bath

Suggested Citation

  • David Metz, 2004. "Travel Time - Variable or Constant?," Journal of Transport Economics and Policy, University of Bath, vol. 38(3), pages 333-344, September.
  • Handle: RePEc:tpe:jtecpo:v:38:y:2004:i:3:p:333-344

    Download full text from publisher

    File URL:;1-
    Download Restriction: Access to full text is restricted to subscribers.

    As the access to this document is restricted, you may want to search for a different version of it.

    References listed on IDEAS

    1. Mills, David E, 1981. "Ownership Arrangements and Congestion-Prone Facilities," American Economic Review, American Economic Association, vol. 71(3), pages 493-502, June.
    2. Evans, Alan W, 1992. "Road Congestion: The Diagrammatic Analysis: Comment," Journal of Political Economy, University of Chicago Press, vol. 100(1), pages 211-217, February.
    3. Edelson, Noel M, 1971. "Congestion Tolls Under Monopoly," American Economic Review, American Economic Association, vol. 61(5), pages 873-882, December.
    4. Fisk, Caroline, 1979. "More paradoxes in the equilibrium assignment problem," Transportation Research Part B: Methodological, Elsevier, vol. 13(4), pages 305-309, December.
    5. Arnott, Richard & de Palma, Andre & Lindsey, Robin, 1993. "A Structural Model of Peak-Period Congestion: A Traffic Bottleneck with Elastic Demand," American Economic Review, American Economic Association, vol. 83(1), pages 161-179, March.
    6. Vickrey, William S, 1969. "Congestion Theory and Transport Investment," American Economic Review, American Economic Association, vol. 59(2), pages 251-260, May.
    7. Dewees, Donald N, 1979. "Estimating the Time Costs of Highway Congestion," Econometrica, Econometric Society, vol. 47(6), pages 1499-1512, November.
    8. Oakland, William H., 1972. "Congestion, public goods and welfare," Journal of Public Economics, Elsevier, vol. 1(3-4), pages 339-357, November.
    9. Arnott, Richard & de Palma, Andre & Lindsey, Robin, 1990. "Economics of a bottleneck," Journal of Urban Economics, Elsevier, vol. 27(1), pages 111-130, January.
    10. Siamak Ardekani & Robert Herman, 1987. "Urban Network-Wide Traffic Variables and Their Relations," Transportation Science, INFORMS, vol. 21(1), pages 1-16, February.
    11. De Vany, Arthur & Saving, Thomas R, 1980. "Competition and Highway Pricing for Stochastic Traffic," The Journal of Business, University of Chicago Press, vol. 53(1), pages 45-60, January.
    12. Henderson, J. Vernon, 1981. "The economics of staggered work hours," Journal of Urban Economics, Elsevier, vol. 9(3), pages 349-364, May.
    13. Hani Mahmassani & Robert Herman, 1984. "Dynamic User Equilibrium Departure Time and Route Choice on Idealized Traffic Arterials," Transportation Science, INFORMS, vol. 18(4), pages 362-384, November.
    14. Kai Nagel & Steen Rasmussen, 1994. "Traffic at the Edge of Chaos," Working Papers 94-06-032, Santa Fe Institute.
    15. De Meza, David & Gould, J R, 1987. "Free Access versus Private Property in a Resource: Income Distributions Compared," Journal of Political Economy, University of Chicago Press, vol. 95(6), pages 1317-1325, December.
    16. Arnott, Richard, 1990. "Signalized intersection queuing theory and central business district auto congestion," Economics Letters, Elsevier, vol. 33(2), pages 197-201, June.
    17. Berglas, Eitan & Pines, David, 1981. "Clubs, local public goods and transportation models : A synthesis," Journal of Public Economics, Elsevier, vol. 15(2), pages 141-162, April.
    18. Mohring, Herbert, 1970. "The Peak Load Problem with Increasing Returns and Pricing Constraints," American Economic Review, American Economic Association, vol. 60(4), pages 693-705, September.
    19. Small, Kenneth A, 1992. "Trip Scheduling in Urban Transportation Analysis," American Economic Review, American Economic Association, vol. 82(2), pages 482-486, May.
    20. Gordon F. Newell, 1987. "The Morning Commute for Nonidentical Travelers," Transportation Science, INFORMS, vol. 21(2), pages 74-88, May.
    21. Mun, Se-il, 1994. "Traffic jams and the congestion toll," Transportation Research Part B: Methodological, Elsevier, vol. 28(5), pages 365-375, October.
    22. McDonald, John F. & d'Ouville, Edmond L., 1988. "Highway traffic flow and the uneconomic region of production," Regional Science and Urban Economics, Elsevier, vol. 18(4), pages 503-509, November.
    23. Chu Xuehao, 1995. "Endogenous Trip Scheduling: The Henderson Approach Reformulated and Compared with the Vickrey Approach," Journal of Urban Economics, Elsevier, vol. 37(3), pages 324-343, May.
    24. Small, Kenneth A, 1982. "The Scheduling of Consumer Activities: Work Trips," American Economic Review, American Economic Association, vol. 72(3), pages 467-479, June.
    25. Arnott, Richard, 1979. "Optimal city size in a spatial economy," Journal of Urban Economics, Elsevier, vol. 6(1), pages 65-89, January.
    Full references (including those not matched with items on IDEAS)


    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.

    Cited by:

    1. Holz-Rau, Christian & Scheiner, Joachim, 2011. "Safety and travel time in cost-benefit analysis: A sensitivity analysis for North Rhine-Westphalia," Transport Policy, Elsevier, vol. 18(2), pages 336-346, March.
    2. José Manuel Viegas, 2012. "The urban mobility system and regional competitiveness," Chapters,in: Networks, Space and Competitiveness, chapter 2, pages 35-55 Edward Elgar Publishing.

    More about this item


    Access and download statistics


    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:tpe:jtecpo:v:38:y:2004:i:3:p:333-344. See general information about how to correct material in RePEc.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Christopher F. Baum). General contact details of provider: .

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    We have no references for this item. You can help adding them by using this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service hosted by the Research Division of the Federal Reserve Bank of St. Louis . RePEc uses bibliographic data supplied by the respective publishers.