Modelling Road and Rail Transport in the Short Term: Application and Results
Modelling road and rail transport in the short term: application and results
We present a model developped for the use of the French Ministry of Transportation, and financed by its main Directions (DRAST, DTT), with the objective of taking into account exogenous variables for predicting national transport activity one-to-two years ahead.
The paper deals with a model for short-term total demand for land transport, relating passenger and freight traffic to their main determinants, representative of transport supply (prices, networks length) and demand(production/consumption). We adopted first a modal approach that treats road and rail transport separately, and then a bimodal road/rail approach. The model was constructed on a quaterly basis, on the period 1980-1998.
In the modal approach, we used ARIMAX modelling with exogenous variables, and then vectorial auto-regressive modelling with exogenous variables (VARX)in the bimodal approach.
The elasticity values of the modal traffic indicators with regard to their main determinants are discussed, and compared to other values obtained with annual models constructed on the same data, or obtained with other methods.
We discuss the model's empirical performance. Although statistically superior, the bimodal form is not easy to interprate, the supply and demand effects being hard to separate.
Association for European Transport