This study is concerned with the structure of travel demand models. Two alternative structures are defined, simultaneous and recursive, that are based on different hypotheses about the underlying travel decision-making process. The simultaneous structure is very general and does not require any specific assumptions. The recursive structure represents a specific conditional decision structure, i.e., the traveler is assumed to decompose his trip decision into several stages. Thus, simultaneous and recursive structures represent simultaneous and sequential decision-making processes. Theoretical reasoning indicates that the simultaneous structure is more sensible. Moreover, if a sequence assumption is accepted, there are several conceivable sequences, and generally there are no a priori reasons to justify a selection among them. A simultaneous model, howover, is very complex because of the large number of alternatives selection among them. A simultaneous model, however, is empirical study is conducted to investigate the feasibility of a simultaneous model and to appraise the sensitivity of predictions made by a travel demand model to the structure of the model. The data set for the study was drawn from conventional urban transportation study data. Included in a trip decision are destination and mode choices. With the same data set, three disaggregate probabilistic models are estimated for the shopping trip purpose: a simultaneous model and two recursive models with two possible sequences. The simultaneous model proved to be feasible in terms of the computational costs and the estimation results. The results of the recursive models showed that estimated model coefficients vary considerably with different model structures. The simultaneous model structure is recommended.

Media Info

  • Media Type: Print
  • Features: References; Tables;
  • Pagination: pp 26-42
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00096443
  • Record Type: Publication
  • ISBN: 0309023734
  • Files: TRIS, TRB
  • Created Date: Jul 15 1981 12:00AM