A review of freight modelling procedures

This paper reviews the current practice of modelling freight movements for highway planning purposes. It is noted that few, if any models are explanatory and there is normally a two stage process involving a Macro Forcasting Model that predicts overall changes in vehicle miles, tons lifted and vehicles operated and a Local Spatial Model that predicts changes of movement patterns constrained to the totals provided by the Macro Model. Alternative forms of Spatial Models are described with examples how they have been used and suggestions are made of where improvements could be undertaken.