• Urban dispersion
• Spatial structure
• Regional development
• Polycentricity
• Agglomeration economies
• Urban regions

The aim of this thesis is contributing to the debate about the organization of economic activities across space and its impacts both on economic competitiveness and on environmental sustainability.
The first chapter states the most important aspects of spatial structure, which are polycentric development and urban dispersion, and highlights the relevance of spatial economic organization for public policies, in particular with reference to the spatial policies addressed by the European Union.
In order to assess the effects of spatial structure, the second chapter tackles the issue of the analytical definition and measurement of polycentricity and dispersion. By surveying the most relevant literature in urban and regional economics, and geography and spatial planning, the chapter illustrates the main analytical dimensions and the empirical methods for the measurement of spatial structure at regional level, providing an empirical illustration on Italian regions.
The third chapter analyses the relationships between spatial structure and economic competitiveness in Italian NUTS-3 regions. It presents the theoretical framework, grounded on agglomeration economies literature, and check whether agglomeration economies may depend on spatial organization of economic activities across Italian regions. In the empirical analysis labour productivity is taken as a proxy for economic competitiveness and both of polycentricity and urban dispersion seems to have negative impacts.
The fourth chapter analyses the links between spatial structure and environmental pressure. The latter have been measured by gas emissions generated by private road transport and house heating. After the literature review, the chapter shows, through regression analysis of NUTS-3 regions, that spatial structure influences CO2 emissions from transport and PM10 emissions from house heating, with no evidence that polycentricity helps in reducing emissions.
The thesis concludes discussing the main results from the empirical part of the work and sketch further steps in the analysis of spatial structure and economic development.