ON THE EQUIVALENCE OF COMMON REARRANGEMENTS FOR SUM CONSTRAINED TRAVEL ESTIMATION PROBLEMS

This paper examines tthe problem of estimating the parameters of nonlinear sum constrained models by use of rearrangements to permit linear estimation methods. Over the years a number of different, and sometimes ingenious, techniques have been proposed but a remaining difficulty arises from the fact that different rearrangements lead to different parameter estimates. In this paper it is shown that while ordinary least squares certainly results in different estimates, generalised least squares leads to identical parameter estimates provided convergence to the true maximum likelihood estimates is achieved. In particular it is seen that estimates are invariant with choice of base or deletion of one equation and identical for the single base, multinominal logit, geometric mean and link constant versions. The findings of this paper apply to any sum-constrained model and in transportation these occur very frequently as mode choice problems, singly-constrained gravity models, and as route choice models in path assignment. While we develop all results in this paper in the context of an intercity passenger model market share model, the transferability of these results to other problems should be recognised. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/01912615
• Corporate Authors:

  Pergamon Press, Incorporated

  Headington Hill Hall
  Oxford OX30BW,    
• Authors:
  • WILLS, M J
• Publication Date: 1982-10

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 339-359
• Serial:
  • Transportation Research Part B: Methodological
  • Volume: 16B
  • Issue Number: 5
  • Publisher: Elsevier
  • ISSN: 0191-2615
  • Serial URL: http://www.sciencedirect.com/science/journal/01912615

Subject/Index Terms

• TRT Terms: Forecasting; Gravity models; Intercity transportation; Itinerary; Mathematical models; Modal split; Mode choice; Regression analysis; Routes; Transportation modes; Travel; Travel demand
• Uncontrolled Terms: Models; Selection
• Old TRIS Terms: Modal selection
• ITRD Terms: 132: Forecast; 690: Gravity model; 388: Inter urban; 699: Itinerary; 698: Journey; 6473: Mathematical model; 675: Modal split; 6588: Regression analysis; 9072: Selection; 1145: Transport mode
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management; Planning and Forecasting; I71: Traffic Theory; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00370318
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Feb 28 1983 12:00AM