Autobahns of Austria

Ideas to build up a limited-access road network with grade separated interchanges had been developed already in the 1920s, including a "Nibelungen" highway along the Donau (Danube) river from Passau to Wien (Vienna) and further on towards Budapest.

Those plans however had never been carried out due to the lasting economic crisis that hit the country after the dissolution of Austria-Hungary in 1918, exacerbated by the Great Depression.

Building started immediately after the Austrian Anschluss in 1938 the annexation of Austria on order of Adolf Hitler as extension of the German Reichsautobahn-Strecke 26 from München (Munich) (the present-day Bundesautobahn 8).

After the war delaying resistance by the Soviet occupation forces as well as claims raised by West Germany to the former Reichsautobahn assets obstructed the resumption until 1954.

Construction started in the US-occupied zone of Salzburg and Upper Austria, partly relying on the pre-war planning, and were extended after the country gained full sovereignty by the 1955 Austrian State Treaty.

Unusually for European countries, interchanges (between motorways called Knoten, "knots") are numbered by distance in kilometres starting from where the route begins.

The transit traffic across the main chain of the Alps, especially by trucks, has led to a considerable environmental load to the fragile Alpine ecosystem.

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.

Since 2004 trucks must carry the GO-Box, a little white box which counts the length of the Autobahn used by way of electrical control points, queried by overhead DSRC microwave radio transceivers at different locations.