for: Audubon

Autobahn (German: IPA2: ˈaʊtoːbaːn, plural Autobahnen; English: /ˈɔːtəʊbɑːn/) is the German word for a major high-speed road restricted to motor vehicles capable of driving at least and having full control of access, similar to a motorway or freeway in English-speaking countries.

In most countries, it usually refers to the German autobahn specifically. The recommended speed of the German autobahn is , but there is no general speed limit. Austrian and Swiss autobahns have general speed limits of and , respectively. In German, the word is pronounced as described above, and its plural is Autobahnen; in English, however, the segment "auto" is typically pronounced as in other English words such as "automobile". The official name of the autobahn in Germany is Bundesautobahn (BAB) (Federal Freeway). Autobahns are built and maintained by the federal government (as are the federal highways), thus the name "Federal Freeway". The first were built in the 1920s, and in the 1930s the official name was "Reichsautobahn" (Freeways of the Reich).

Germany

Just like all European highways, autobahns have multiple lanes of traffic in each direction, separated by a central barrier with grade-separated junctions and access restricted to certain types of motor vehicles only. The first road of this kind was completed in 1931 between Cologne and Bonn and opened by Konrad Adenauer (Lord Mayor of Cologne and future Chancellor of West Germany) on 6 August 1932. This road was not yet called Autobahn, but instead was known as a Kraftfahrtstraße (lit. automobile road). The idea was a street which had no crossings and was only to be used by cars and motorcycles and not by pedestrians or the common horse drawn carts. As Adolf Hitler did not become Chancellor until afterwards in January 1933, the claim that the Autobahn was conceived by the Nazis is a myth.

Nevertheless, for a variety of reasons, the Nazi regime pressed ahead with the construction of the Autobahn system. This created jobs and reduced the unemployment rate, though slave labour was used at this time. The Autobahn also possibly served another purpose: the road connection between various regions within Germany could make military defense and logistics much more efficient and rapid in response. In addition, with the availability of road access, Germans could now easily travel (and relocate) to various regions within Germany, thus weakening regional differences and (in the long run) bringing about a more singular popular vision of a united Germany.

Each Reichsautobahn carriageway was flanked by banquettes about 60 cm in width, constructed of varying materials; right-hand banquettes on many autobahns were later retrofitted to 120 cm in width when it was realized cars needed the additional space to pull off the autobahn safely. In the postwar years, a thicker asphalt concrete cross-section with full paved hard shoulders came into general use. The maximum design speed was approximately 80 km/h in flat country but lower design speeds could be used in hilly or mountainous terrain. A flat-country autobahn constructed to published design standards in use during the Nazi period could support hands-off (banking of the roadway where the car would track straight, despite the curvature of the road) speeds on curves of about 40 km/h.