Input/output models for freight transport demand: a macro approach to traffic analysis for a freight corridor

Input Output model are of great interest in the transport sector, especially regarding freight transport demand. These models allow to analyze the cross effects of: political, macroeconomic and transport changes; industrial dynamics; exchange flows between different sites within a reference area, more or less divided into subareas. Although very interesting and desirable to be used and disseminated, their use is often hindered by the complexity of the modelling structures that need to describe the interactions with the transport systems and by the difficulty of finding complete and reliable data. In this context, this paper deals with a macro-level Input Output approach for freight demand analysis, which directly relates the quantities of goods transported along a multimodal corridor to the functioning of the economic system. The proposed model is structured on two levels: the first level allows the sectoral production forecasts of the entire economic system based on the exogenous final demand; the second allows the forecast of tons transported, annually and by sector, along the corridor based on the sectoral production estimated at the first level. The two modelling levels are applied to the analysis and forecast of freight traffic demand along the Italian-Austrian cross-border stretch of the Brenner corridor, a fundamental axis of the European transport infrastructure network. The model has been verified and validated on data covering 15 years between 2000 and 2014 using the reclassified time series of Input Output tables and the international trade data for Italy. The model has been used to produce medium-long term forecasts for different economic scenarios. The macro-level point of view and the application for the corridor provide a simple and directly applicable model compared to the complex articulations that characterize the Input Output applications to the transport systems, which can hinder their concrete use as decision support in the planning of transport infrastructures.