AUTOMOBILE OCCUPANCY, VEHICLE TRIPS, AND TRIP PURPOSE: SOME FORECASTING PROBLEMS

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)

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1984/987/987-002.pdf
• Summary URL:
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• Supplemental Notes:
  • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved. Publication of this paper sponsored by Committee on Traveler Behavior and Values.
• Authors:
  • Ohstrom, Eric G
  • Stopher, Peter R
• Publication Date: 1984

Media Info

• Media Type: Print
• Features: References; Tables;
• Pagination: pp 8-13
• Monograph Title: Travel measurement issues
• Serial:
  • Transportation Research Record
  • Issue Number: 987
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Accuracy; Automobile travel; Case studies; Forecasting; High occupancy vehicles; Logits; Policy; Trip purpose; Vehicle occupancy
• Subject Areas: Highways; Planning and Forecasting; Policy; I10: Economics and Administration;

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