Advanced Search
MyIDEAS: Login to save this paper or follow this series

The Ethical Challenges and Professional Responses of Travel Demand Forecasters

Contents:

Author Info

  • Brinkman, P. Anthony
Registered author(s):

    Abstract

    Thirty years ago scholars first presented convincing evidence that local officials use biased travel demand forecasts to justify decisions based on unstated considerations. Since then, a number of researchers have demonstrated convincingly that such forecasts are systematically optimistic -- often wildly so -- for reasons that cannot be explained solely by the inherent difficulty of predicting the future. Why do modelers -- professional engineers and planners who use quantitative techniques to predict future demand for travel and estimate its potential impact on built and proposed transportation facilities -- generate biased forecasts and otherwise tolerate the misuse of their work? On initial consideration, it is tempting to surmise that corrupt modelers are responsible for biased forecasting. Indeed, corruption is the most common explanation of forecasting bias and tales of mercenary behavior are all too common in the field. Data from in-depth interviews with twenty-nine travel demand forecasters throughout the United States and Canada, however, suggest new and different ways to understand the suspect behavior of transportation planning professionals. Those most likely to introduce bias and invite misuse of travel forecasts assume that their technical analyses have little, if any, impact on policy making. For many, this leads to disillusionment and requires responses to cope with feelings of marginalization. Others, untroubled by their apparent lack of influence, are complacent and need ways to avoid the ethical questions of practice. Both types of practictioners circumscribe professional roles and rely on the self-deceptive strategies of evasion and excuse making to mute their own disquieting realities that undermine positive concepts of self. This disillusion wish not to see that they do not matter and the complacent that they do. Bias and misuse seem to be the unintentional byproducts of these attitudes. Beyond enhancing the understanding of the systemic failures of travel demand modeling, this research suggests practicable steps to reform and outlines an agenda for future work. Attention to these matters is important, not just to avoid expenditures on projects and programs that cannot be justified on the basis of sound utilitarian calculations, but also to restore and preserve the credibility of a profession.

    Download Info

    If you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.
    File URL: http://www.escholarship.org/uc/item/7vb2d17h.pdf;origin=repeccitec
    Download Restriction: no

    Bibliographic Info

    Paper provided by University of California Transportation Center in its series University of California Transportation Center, Working Papers with number qt7vb2d17h.

    as in new window
    Length:
    Date of creation: 01 Sep 2003
    Date of revision:
    Handle: RePEc:cdl:uctcwp:qt7vb2d17h

    Contact details of provider:
    Postal: 109 McLaughlin Hall, Mail Code 1720, Berkeley, CA 94720-1720
    Phone: 510-642-3585
    Fax: 510-643-3955
    Email:
    Web page: http://www.escholarship.org/repec/uctc/
    More information through EDIRC

    Related research

    Keywords: Social and Behavioral Sciences;

    References

    References listed on IDEAS
    Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
    as in new window
    1. A. P. Thirlwall, 1983. "Introduction," Journal of Post Keynesian Economics, M.E. Sharpe, Inc., vol. 5(3), pages 341-344, April.
    2. Rubin, Thomas A. & Moore II, James E. & Lee, Shin, 1999. "Ten myths about US urban rail systems," Transport Policy, Elsevier, vol. 6(1), pages 57-73, January.
    3. Mackett, Roger L. & Edwards, Marion, 1998. "The impact of new urban public transport systems: will the expectations be met?," Transportation Research Part A: Policy and Practice, Elsevier, vol. 32(4), pages 231-245, May.
    4. Skamris, Mette K. & Flyvbjerg, Bent, 1997. "Inaccuracy of traffic forecasts and cost estimates on large transport projects," Transport Policy, Elsevier, vol. 4(3), pages 141-146, July.
    5. Roy T. Meyers, 1996. "If policy analysts are depressed, what should they do about it?," Journal of Policy Analysis and Management, John Wiley & Sons, Ltd., vol. 15(3), pages 438-443.
    6. Brinkman, Anthony & Goldman, Todd, 1998. "Transportation Models In the Policy-Making Process: Uses, Misuses, And Lessons For The Future," Institute of Transportation Studies, Research Reports, Working Papers, Proceedings qt47h925rc, Institute of Transportation Studies, UC Berkeley.
    7. Tore Langmyhr, 2000. "The Rhetorical Side of Transport Planning," European Planning Studies, Taylor & Francis Journals, vol. 8(5), pages 669-684, October.
    8. Mackie, Peter & Preston, John, 1998. "Twenty-one sources of error and bias in transport project appraisal," Transport Policy, Elsevier, vol. 5(1), pages 1-7, January.
    9. Nelson, Robert H, 1987. "The Economics Profession and the Making of Public Policy," Journal of Economic Literature, American Economic Association, vol. 25(1), pages 49-91, March.
    10. Edwards, Marion & Mackett, Roger L, 1996. "Developing new urban public transport systems : An irrational decision-making process," Transport Policy, Elsevier, vol. 3(4), pages 225-239, October.
    11. Goetz, Andrew R. & Szyliowicz, Joseph S., 1997. "Revisiting transportation planning and decision making theory: The case of Denver International Airport," Transportation Research Part A: Policy and Practice, Elsevier, vol. 31(4), pages 263-280, July.
    12. A. Meltzer & Peter Ordeshook & Thomas Romer, 1983. "Introduction," Public Choice, Springer, vol. 41(1), pages 1-5, January.
    Full references (including those not matched with items on IDEAS)

    Citations

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

    Cited by:
    1. Tal, Gil & Cohen-Blankshtain, Galit, 2011. "Understanding the role of the forecast-maker in overestimation forecasts of policy impacts: The case of Travel Demand Management policies," Transportation Research Part A: Policy and Practice, Elsevier, vol. 45(5), pages 389-400, June.

    Lists

    This item is not listed on Wikipedia, on a reading list or among the top items on IDEAS.

    Statistics

    Access and download statistics

    Corrections

    When requesting a correction, please mention this item's handle: RePEc:cdl:uctcwp:qt7vb2d17h. 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: (Lisa Schiff).

    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.

    If references are entirely missing, you can add them using this form.

    If the full references list an item that is present in RePEc, but the system did not link to it, you can help with 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 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.