This paper presents the ASTRA-Italia model, a tool to analyse the long-term effect oftransport policies and investments. In the ASTRA-Italia System Dynamics strategictransport model mobility prediction is the result of a complex interaction process amongfour different components: transport, economy, land-use and environment. The tool isthen capable to illustrate the reciprocal influences among transport and ecological andsocio-economic systems. As an example, the links between passenger and freightmobility and the economic performance are bi-directional, which means that feed-backeffects are simulated showing how modifications in the economic performances mightreinforce (or alternatively dampen) the transport development and vice-versa.The spatial representation of the four modules - transport, economy, land-use andenvironment - is very different and then the common spatial representation in ASTRAItaliais based on a combination of macro-regions – aggregations of the 20 Italianadministrative regions - and functional zones – clusters of the 90 Italian administrativeprovinces according to different settlement types. The transport system is represented bydistance bands (separately for passenger and freight) considering different modal choicealternatives and different driving patterns in dependency of the trip length.The model simulation period covers thirty years (2000-2030) and a reference scenariowas constructed with a projection of past and current trends of key variables. Policypackages can be then tested and compared with such reference case. To exploresustainable paths, the model produces a great variety of quantified indicators includingvariations in: GDP, employment, private consumption, tax revenues, transportperformance (pass*km and tonnes*km), modal shift, vehicle fleet development, trafficemissions, fuel consumption. Monetary values are also estimated for external costs.
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