The Ethical Challenges and Professional Responses of Travel Demand Forecasters
Thirty years ago scholars first presented convincing evidence that local officialsuse biased travel demand forecasts to justify decisions based on unstated considerations.Since then, a number of researchers have demonstrated convincingly that such forecastsare systematically optimisticâ€“often wildly soâ€“for reasons that cannot be explained solelyby the inherent difficulty of predicting the future. Why do modelersâ€“professional engineers and planners who use quantitative techniques to predict future demand for traveland estimate its potential impact on built and proposed transportation facilitiesâ€“generatebiased 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 withtwenty-nine travel demand forecasters throughout the United States and Canada, how-2ever, suggest new and different ways to understand the suspect behavior of transportationplanning professionals.Those most likely to introduce bias and invite misuse of travel forecasts assumethat their technical analyses have little, if any, impact on policy making. For many, thisleads to disillusionment and requires responses to cope with feelings of marginalization.Others, untroubled by their apparent lack of influence, are complacent and need ways toavoid the ethical questions of practice. Both types of practitioners circumscribe professional roles and rely on the self-deceptive strategies of evasion and excuse making tomute their own disquieting realities that undermine positive concepts of self. The disillusioned wish not to see that they do not matter and the complacent that they do. Bias andmisuse seem to be the unintentional byproducts of these attitudes.Beyond enhancing the understanding of the systemic failures of travel demandmodeling, this research suggests practicable steps to reform and outlines an agenda forfuture work. Attention to these matters is important, not just to avoid expenditures onprojects and programs that cannot be justified on the basis of sound utilitarian calculations, but also to restore and preserve the credibility of a profession.
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- 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.
- 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.
- 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.
- 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.
- 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.
- Tore Langmyhr, 2000. "The Rhetorical Side of Transport Planning," European Planning Studies, Taylor & Francis Journals, vol. 8(5), pages 669-684, October.
- A. Meltzer & Peter Ordeshook & Thomas Romer, 1983. "Introduction," Public Choice, Springer, vol. 41(1), pages 1-5, January.
- Kenneth Button & Roger R. Stough (ed.), 1998. "Transport Policy," Books, Edward Elgar, number 1405, April.
- 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.
- 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.
- 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.
- 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.
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