FIGURE 4

Centrality distributions over the network of cycle/pedestrian paths and intersections: (1) the existent network; (2) the proposed network, scenario A: the Spine; (3) the proposed network, scenario B: the Ring. The C ^C distribution appears in all cases deeply affected by the 'edge effect', the distortion that typically groups higher C ^C scores around the centre of the image rather than revealing any structural order of the network. In this case, however, the borders of the image do express a relevant territorial meaning, because the campus is really self-centred and isolated at the fringe of the urban settlement, a peripheral 'island' with just two points of connections with the larger urban system; so in this specific case the picture emerging from the analysis of C ^C represents much more an inherent feature of the real network of the campus than an artificial outcome of the borders' cut. In the existent network (col. 1), a spine of higher centrality emerges along the distribution road, which is mostly vehicular channel that presents environmental conditions rather aggressive for pedestrians and cyclists; moreover, almost all buildings on campus are well detached from the road, significantly weakening its attractiveness for pedestrians and cyclists. The proposed realization of a continuous cycle/pedestrian path (col. 2, scenario A) that runs well beyond the distribution road and links together all activity centres and the systems of local spatial centres on campus is blessed by a great centrality potential for all indices. Most important, the new path is continuously central, with no significant local drops, weakening the previously dominant centrality system of the distribution road. In a way, the new path effectively 'drains' centrality flows from over the system, while at the same time resulting mostly consistent with the local structure of places' centrality (Figure 3, bottom). The alternative proposal (col. 3, scenario B) does not exhibit a comparable success. The idea of building a ring that includes part of the distribution roads lacks an acceptable level of centrality especially in the north-eastern side, with particular reference to C ^B and C ^I. The realization of such a ring would probably lead to a more confused system and a certain waste of financial and territorial resources.