Title: Scaling in public transport networks
Authors: C. von Ferber (Theoretische Polymerphysik, Universität Freiburg, D-79104 Freiburg, Germany), Yu.Holovatch (Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine; Institut für Theoretische Physik, Johannes Kepler Universität Linz, A-4040 Linz, Austria; Ivan Franko National University of Lviv, 79005 Lviv, Ukraine), V.Palchykov (Ivan Franko National University of Lviv, 79005 Lviv, Ukraine)

We analyse the statistical properties of public transport networks. These networks are defined by a set of public transport routes (bus lines) and the stations serviced by these. For larger networks these appear to possess a scale-free structure, as it is demonstrated e.g. by the Zipf law distribution of the number of routes servicing a given station or for the distribution of the number of stations which can be visited from a chosen one without changing the means of transport. Moreover, a rather particular feature of the public transport network is that many routes service common subsets of stations. We discuss the possibility of new scaling laws that govern intrinsic properties of such subsets.

Key words: scale-free networks, scaling, Zipf law
PACS: 89.75.-k, 89.75.Da, 05.65.+b