Donauuferautobahn

The Austrian autobahns are controlled-access highways in Austria. They are officially called Bundesstraßen A (Bundesautobahnen) under the authority of the Federal Government according to the Austrian Federal Road Act (Bundesstraßengesetz), not to be confused with the former Bundesstraßen highways maintained by the Austrian states since 2002.

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.

The first autobahn on Austrian territory was the West Autobahn from Salzburg to Wien. 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). However, only 16.8 km (10.4 mi) including the branch-off of the planned Tauern Autobahn had been finished on 13 September 1941. Construction works discontinued the next year due to World War II. 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.

...
Wikipedia