 Austria currently has 18 autobahns, since 1982 built and maintained by the self-financed ASFiNAG stock company in Vienna, which is wholly owned by the Republic of Austria and earns revenue from road user charges and tolls.Each route bears a number as well as an official name with local reference, which, however, is not displayed on road signs.Unusually for European countries, interchanges (between motorways called "Knoten", "knots") are numbered by distance in kilometres starting from where the route begins.