Struttura di costo e rendimenti di scala nelle imprese di trasporto pubblico locale di medie-grandi dimensioni

In this paper we analyse the cost structure of a sample of Italian Local Public Transport (LPT) companies operating in large urban centres, so as to extend the evidence of some recent studies focused on small-sized and medium-sized operators. The main focus is to verify the presence and the extent of both scale and density economies. Technological characteristics of LPT systems are analysed by estimating a variable cost function model, which includes firm-specific fixed effects and considers three alternative supply-oriented output measures. The results show the presence of short-run and long-run scale economies, as well as of economies of network density, for both the average sample firm and companies belonging to the highest percentile (large-sized operators), regardless of the type of service provided (urban or mixed). This evidence suggests that, from a technological point of view, a proper LPT network should at least include a large urban centre and should be extended so as to embrace the intercity service too, while a regulatory policy aimed at fragmenting the served area in various sub-networks would imply a loss of productive efficiency.