A National Commodity Flow Model

Abstract

This paper describes a pilot study of the development of a national commodity flow model for Canada. The aim is to develop a modelling capability that can estimate the commodity movement implications of probable changes in development and in the transport system. The model described in this paper concentrates on estimating the implications of alternative development patterns. The basic inputs to the model are spatially disaggregated allocations of population and of employment by industry sector. The principal outputs from the model are the annual tonnages of freight on each link of each modal transport network. Data inputs to the model and the model parameters are derived principally from information collected and published by Statistics Canada.The structure of the model is similar to the model structure used in urban transport planning studies. It proceeds from the estimation of commodity productions and consumptions, through the estimation of commodity distributions patterns and modal split by mode to network assignment.Preliminary results from the commodity flow model using a 1971 data base are described along with a very limited appraisal of the model outputs using independent information on Canadian commodity flows. Plausible results were obtained from the model and the assembly of an improved data base should lead to a well-developed national commodity flow model for Canada. Such a model may then be used to examine the freight movement implications of alternative patterns of urbanization in Canada and to evaluate alternative transport supply decisions for the various modes of transport.