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This article underscores the utility of relying upon a categorization of interconnections in order to introduce innovation into regional analyses or into operational involvement at the regional level. More specifically, once a typology of interconnections has been derived, our task turns to observing : - how the interconnection of links, which reflect the complexity of mobility exchange centers, is oriented towards cross-sector intervention, as exhibited in major urban projects ; - how regional interconnections (identification of « local-insertion » systems) necessitate the experimentation of new aggregation and participation tools from the bottom-up ; - how the interconnection among actors, who tend to shape the processes of planning and negotiation, can be set up by means of coordination-based procedures for guiding social interactions.

The majority of research conducted on the spatial transformations caused by transportation infrastructure projects has acknowledged that all ensuing structural effects depend upon the actions of specific target populations and thereby cannot be fully explained without making reference to the rationality of the actors involved. The development of interconnection nodes has provided a good number of examples along these lines. This article presents a total of six case studies in Italy of nodes pertaining both to freight transportation (an arc-shaped network of ports along the Ligurian and Tyrrhenian Seas, intermodal platform projects, the « Cargo City » complex located near Milan) and to passenger transportation (the « Malpensa Express », terminus of the Milan-to-Sesto San Giovanni subway line, the high-speed rail line running through the Susa Valley outside of Torino), in the aim of describing the role and rationale of project actors. A comparison of these case studies enables drawing some useful indications on the relationship existing between the rationale of actors and the structural conditions framing the action.

This article examines the potential offered by the use of interconnections in reconfiguring the relationship between infrastructure-oriented policies and regional land use policies, through analyzing the various forms of action being carried out at interconnection nodes. The concept of interconnection, which provides tremendous insight into operational aspects, is applied in order to determine the spatial dimensions of infrastructure networks. The article forwards the hypothesis that each specific type of project corresponds to a distinct form of interconnection: - the interconnection of physical networks, which concerns above all node-related projects (train stations, subway stations, etc.), « systems » designed to both facilitate access to networks and connect networks with the local spatial layout ; - interconnection as reflected in a large-scale local-level project, able to incorporate the various local settings being networked, by capitalizing on both the tangible and intangible relationships developed between exchange centers ; - interconnection among actors (both institutional and non-institutional) with respect to the decision-making system, through establishing new expressions of negotiation and coordination for overcoming project-related deficiencies. These three formats, which highlight the role played by interconnection in redefining the relationship between infrastructure-oriented policies and land use policies at the regional level, are then exhibited through three planning programs drawn from Italian experience : - the Modena train station rehabilitation project (a physical network interconnection) ; - regional development policy, in conjunction with forecasted infrastructure-related needs, in Lombardy (interconnection via a large-scale regional project) ; - the northern Milan bypass road project, first proposed in the 1960' s yet still not completed (Gronda Intermedia) (interconnection among actors).

Since all trip-making in motor vehicles is constrained by the layout of transportation networks, only those spatial sectors being served by such networks actually turn out to be accessible. The Euclidean model, which defines the accessible surface A for a distance R from a point as : A - kR2, therefore seems to be less capable of effectively modeling this spatial relationship. Due to differences in performance (incomplete spatial coverage, variations in the speed of change), road network patterns serve to generate complex shapes in motorists' isochronal contours, which as opposed to resembling symmetrically filled-in disks tend to stretch out along the directions traversed by roads while containing some pockets of inaccessibility closer to the center. In order to define a more realistic model of land area accessibility that incorporates the quality of the spatial configuration of road transportation networks, we are proposing an approach based on fractal geometry. Such an approach presumes that space is not necessarily homogeneous and isotropic, a presumption which improves the understanding of our effective relationship with space. Keywords: Network, Accessibility, Fractal geometry, Morphology

The spatial configuration of road transportation networks : A fractal approach Since all trip-making in motor vehicles is constrained by the layout of transportation networks, only those spatial sectors being served by such networks actually turn out to be accessible. The Euclidean model, which defines the accessible surface A for a distance R from a point as : A - kR2, therefore seems to be less capable of effectively modeling this spatial relationship. Due to differences in performance (incomplete spatial coverage, variations in the speed of change), road network patterns serve to generate complex shapes in motorists' isochronal contours, which as opposed to resembling symmetrically filled-in disks tend to stretch out along the directions traversed by roads while containing some pockets of inaccessibility closer to the center. In order to define a more realistic model of land area accessibility that incorporates the quality of the spatial configuration of road transportation networks, we are proposing an approach based on fractal geometry. Such an approach presumes that space is not necessarily homogeneous and isotropic, a presumption which improves the understanding of our effective relationship with space. Keywords: Network, Accessibility, Fractal geometry, Morphology