Speed limits in Germany
In 1973, in the wake of the 1973 oil crisis, a federal speed limit of 100 km/h (62 mph) on Autobahns was imposed to help conserve fuel for fear of impending future shortages (not for environmental or safety reasons). The measure only lasted from December 1973 to March 1974; while the administration and the Bundestag were in favor of keeping the speed limit, the Bundesrat pushed to repeal the law. As a compromise, a "recommended speed" was introduced on Autobahns and "highways outside of built-up areas with a center divide or without a center divide and a continuous lane for overtaking in both directions". This law is basically still in effect today. Unrestricted non-Autobahn highways, however, have since become virtually non-existent or replaced by "Schnellstraßen", Autobahn-like expressways typically limited to 120 or 130 km/h and normally only covering a few kilometers.
Autobahn
Only federally built controlled-access highways with certain construction standards including at least two lanes per direction are called "Bundesautobahn". They have their own white-on-blue signs and numbering system. In the 1930s, when construction began on the system, the official name was "Reichsautobahn". Various other controlled-access highways exist on the federal "(Bundesstraße)," state "(Landesstraße)," district, and municipal level but are not part of the "Autobahn" network and are officially referred to as "Kraftfahrstraße" (with rare exceptions, like A 995 Munich-Giesing–Brunntal). These highways are considered "autobahnähnlich" (autobahn-like) and are sometimes colloquially called "Gelbe Autobahn" (yellow autobahn) because most of them are "Bundesstraßen" (federal highways) with yellow signs. Some controlled-access highways are classified as "Bundesautobahn" in spite of not meeting the autobahn construction standard (for example the A 62 near Pirmasens).