Construction of basis OD matrices for 1999 freight flows between municipalities in Norway

The objective of this paper is to describe how data from production and commodity statistics was used to construct basis OD matrices for freight transport between all pairs of municipalities. OD matrices were constructed for 11 commodity groups that together cover all freight transport along road, by train and by boat. A model was built where the basic principle is to balance data for transport in, out and within the municipalities such that the tonnes sent equals the tonnes received (i.e., mass balance). Doubly constrained gravity models were implemented with the balanced data and additional count statistic data to put constraints on the OD pattern at 15x15 aggregate zoning level. The gravity model was applied and the balanced OD matrices were subsequently evaluation by comparison with OD patterns at 39x39 aggregate zoning level based on the count statistics.