Bundesstraße
One distinguishing characteristic between German "Bundesstraßen" and "Autobahnen" is that there usually is a general 100 km/h (62 mph) speed limit on federal highways out of built-up areas, as opposed to the merely advisory speed limit ("Richtgeschwindigkeit") of 130 km/h (83 mph) in unmarked sections of the autobahns. However, a number of "Bundesstraßen" have been extended as expressways (dual carriageways) (colloquially called "Yellow Autobahns"). Many of these have speed limits of usually 100–120 km/h, others have only an advisory speed limit like autobahns. Most sections of the federal highways are only single carriageway with one lane for each direction and no hard shoulder pull-out area.
Reichsautobahn
The specifications for the autobahns were based on those developed by HAFRABA. They were designed as four-lane limited-access highways, with a central median, road surfaces in each direction normally wide (widened on some major segments immediately before the war), surfaced in concrete. There were no shoulders. In addition to having no intersections, the route was to limit grades as much as possible, to no more than 8%, and curves were to fall within a range of and in radius. One segment just south of Dessau of roughly 10 km in length was designed for speed record attempts (the "Dessauer Rennstrecke") and had six lanes in each direction.