The Wharton EFA Automobile Demand Model was developed in 1976 by Wharton Econometric Forecasting Associates, Inc., for the Transportation Systems Center of the U.S. Department of Transportation. This stock-adjustment econometric model is a large-scale model of automobile demand. It has been used widely by federal agencies in policy analyses. However, no major analyses of the model were performed before it was applied and, in some instances, the model was used inappropriately. This paper reports the results of an analysis of the model performed by staff of the Highway Safety Research Institute's Policy Analysis Division at the University of Michigan. The structure of the model was examined. An attempt was made to reconstruct the key time- series equations of the model, the forecasting ability of the model was examined, and sensitivity testing was performed. Computer tapes of the model and data used in the analysis were obtained from the Transportation Systems Center. The analysis uncovered several major problems with the model. New-car sales are partitioned into size classes by using an unjustifiable approach, and some major policy variables (for example, gasoline price) are employed unrealistically in the model. These and other problems combine to seriously weaken the forecasting and policy analysis capabilities of the model. Because of this, policy analysts should use the model only with extreme caution. (Authors)

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 89-96
  • Monograph Title: Transportation energy: data, forecasting, policy and models
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00331035
  • Record Type: Publication
  • ISBN: 0309031079
  • Files: TRIS, TRB
  • Created Date: Jun 12 1981 12:00AM