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.
Autobahn
Just prior to the 1973 oil crisis, Germany, Switzerland, and Austria all had no general speed restriction on autobahns. During the crisis, like other nations, Germany imposed temporary speed restrictions; for example, on autobahns effective 13 November 1973. Automakers projected a 20% plunge in sales, which they attributed in part to the lowered speed limits. The 100 km/h limit championed by Transportation Minister Lauritz Lauritzen lasted 111 days. Adjacent nations with unlimited speed autobahns, Austria and Switzerland, imposed permanent limits after the crisis.