The problems with estimating automobile occupancy by trip purpose for use in travel forecasting and in the policy decisions that frequently follow from forecasts are described. Investigations of data and development of logit models of mode choice reveal that the occupants of multioccupant automobiles frequently have disparate trip purposes, even within the restricted trip-purpose definitions usually encountered in practical transportation planning. These disparate purposes mean that, although occupants can be classified by trip purpose, the automobile vehicle cannot be defined as being used for a single trip purpose, as is necessary to compute accurately the automobile occupancy for a purpose and to convert automobile-person trips by purpose to automobile-vehicle trips for assignment of automobile vehicles to the highway network. This has serious repercussions on a variety of contemporary policy decisions. The problems are discussed, and some alternative procedures that can be used as a compromise computation of vehicle occupancy by purpose are given. The problems and solutions are demonstrated in the context of a case study. (Author)

Media Info

  • Media Type: Print
  • Features: References; Tables;
  • Pagination: pp 8-13
  • Monograph Title: Travel measurement issues
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00399276
  • Record Type: Publication
  • ISBN: 0309037719
  • Report/Paper Numbers: HS-038 816
  • Files: HSL, TRIS, TRB
  • Created Date: Sep 30 1985 12:00AM