Inter-urban Transit Connections: A Network Analysis in an Italian Region

Connectivity between urban centers is a key element for the development of territories. Public transport by road and rail are the two modes of transport most affected by extra-urban connections by land on a regional scale. To analyze these connections, it is interesting to refer to the methods offered by Network Analysis (NA). In this paper, we want to study the centrality characteristics of interurban transport networks - both bus and train - on a regional scale, taking as a reference the direct connections between cities. This allows us to identify gaps and define hierarchies of network nodes, starting from the movement possibilities present in a node compared to the others. NA is the methodology used; it allows to obtain synthetic centrality indicators in a network. In this article, two of the main indicators of NA (i.e., Degree Centrality, Strength Centrality) are applied to a test case of regional extension. Methodology used involves evaluation of Degree Centrality in a time-constrained network. Two different networks are considered and compared: the railway and the extra-urban bus transport network. The methodology considered allows to evaluate the centrality of the urban nodes considered with respect to each of the two networks; in this way, it is possible to compare the centrality values on the two networks between them. The case study highlighted is the Sicilian region, in Southern Italy. The analysis involves the study of centrality of the region’s main cities. The results highlight asymmetrical differences between the different territories considered and large margins for improvement of the network. Furthermore, among the conclusions, it is interesting to recall the distortions present between the two modes of transport studied.