A method for manually calibrating the gravity model using elementary analysis is described. Requisite for the method is an O-D matrix, which is first transformed to logarithms before column and row averages are subtracted, resulting in a residuals matrix. The same operation is performed in a matrix of distances yielding a distance residuals matrix. These two residuals are graphed to determine the friction term of the gravity model. This friction factor, computed for a sample from a suburban circumferential corridor, was applied to another sample. Using the gravity model, the O-D matrix is estimated in a straightforward, noniterative manner, yet they are remarkably similar to the actual trip matrix. The method is proposed as a useful trip distribution modeling and forecasting technique, whenever the study is relatively small and quick results are desired. Larger problems may use the same method but require computer analysis.

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  • Accession Number: 00188912
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Mar 28 1979 12:00AM