Resumen
The development of cities and transportation systems of the last few years made possible to expand the range of individuals, giving them the opportunity to locate their residence far away from the places where they carry out daily activities. The ability to make long journeys has become more and more an essential condition to access opportunities of the territory. This necessity can be connected to transportation social need, which scholars define both in terms of people requiring a public transportation service and number of trips they would make if they had minimal limitations on their mobility; accessibility refers to the ease of reaching goods, services, activities and destinations, which together are called opportunities. This research presents the application of a measure of transportation social need and accessibility for the city of Catania, in Italy. The measure of transportation social need, based on transportation and social disadvantage indicators, has been carried out with reference to Italian national statistical institute zonation of the city. A zonal accessibility measure, considering both private and public transportation and evaluating the ease of reaching desired destinations, have been calculated and an analysis of correlation among transportation social need measure and accessibility measures has been carried out in order to verify the strength of relation between them. Due to the high resolution level of the spatial analysis, manipulation of data and computation of indicators and measures was supported by a GIS approach. Three different public transport scenarios have been analyzed by performing a relative accessibility loss computation showing that improvements in public transport service lead to general improvements in relative accessibility loss.