Travel models are commonly used to forecast vehicle-kilometers traveled (vehicle-miles traveled) and speed, from which mobile source emissions are calculated. Most existing models were developed for planning transportation facility improvements and are not well suited for analyzing pricing strategies. Since these models still represent the best available travel database in most urban areas, there is a desire to adapt them to meet a wider range of needs. The Environmental Protection Agency (EPA) recently commissioned a study on the effects of transport pricing on emissions. This required a planning tool that could analyze many different pricing actions. This project borrowed parts of existing good models to create a pricing-sensitive model set. The resulting model was applied using actual data from one area, for more realistic results. This approach represents an incremental advancement in modeling practice by successfully combining features of the more advanced four-step models. Trip distribution uses a composite definition of impedance that reflects time and cost of all modes. Mode choice is a logit model with some degree of nesting in the carpool mode; it is sensitive to peak and off-peak automobile operating cost, tolls, transit fare, and parking cost. A logit path choice procedure models the effect of tolls on drivers' selection of free and priced paths. All highway paths are based on a combined time and cost impedance. Emissions are sensitive to changes in vehicle age mix, as adjusted based on age- or emissions-based registration fees. The focus of this study is on changes in forecasting methodologies; therefore, results of this analysis are not presented. They are available in the EPA report.


  • English

Media Info

  • Features: Figures; References;
  • Pagination: p. 75-81
  • Monograph Title: Transportation finance, training, strategic management, and economic analysis
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00714967
  • Record Type: Publication
  • ISBN: 0309061628
  • Files: TRIS, TRB, ATRI
  • Created Date: Dec 21 1995 12:00AM