THE FORECASTING ABILITY AND TEMPORAL STABILITY OF THE COEFFICIENTS OF GRAVITY MODELS APPLIED TO TRUCK TRAFFIC

It is argued that the use of a gravity model for forecasting assumes that the coefficients used in the model are constant over time. This article reports a test of this assumption using data on truck movements into Chicago for 1956 and 1970. The 1956 model, modified to take account of differences in the study area in 1970, was used to predict 1970 truck flow and found to underestimate the total number of trips. Recalibration of the model with 1970 data revealed the extent to which the coefficients had changed. This procedure was repeated with a multiple regression model. The significance of changes in the coefficients is discussed. /TRRL/

  • Availability:
  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • Byler, J
    • O'Sullivan, P
  • Publication Date: 1974-2-3

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Filing Info

  • Accession Number: 00096743
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Sep 30 1975 12:00AM