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.
Speed limits in the United States by jurisdiction
As of October 31, 2017, the speed limit law is being broken into four categories: rural interstates, Urban Interstates, rural divided unlimited access highways, and two lane highways. There are studies being made to increase rural interstate speed limits to 75 mph (121 km/h), urban interstate speed limits to a uniform 65 mph (105 km/h) speed limit, rural divided unlimited access highways to 65 mph (105 km/h) unless the DOT warrants a lower speed, and maintaining a 55 mph (89 km/h) speed limit with the option of increasing the limit to 60 mph (97 km/h) where higher speed limits can be warranted on two lane highways (as of July 1, 2018, no freeways in Arkansas have been increased to 75 mph).