 "Schnellstraßen" (officially "Bundesstraßen S") are federal limited-access roads very similar to "Autobahnen"; the chief difference is that they are more cheaply built with fewer tunnels, mostly just following the given topography.Depending on the road extension, they are either signposted as "Autobahn" or "Autostraße" according to Austrian traffic regulations.The speed limit on "Schnellstraßen" is 100 km/h, however on some it is 130 km/h indicated by a sign.