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.
Vision Zero
Vision Zero suggests the following "possible long term maximum travel speeds related to the infrastructure, given best practice in vehicle design and 100% restraint use". These speeds are based on human and automobile limits. For example, the human tolerance for a pedestrian hit by a well-designed car is approximately 30 km/h. If a higher speed in urban areas is desired, the option is to separate pedestrian crossings from the traffic. If not, pedestrian crossings, or zones (or vehicles), must be designed to generate speeds of a maximum of 30 km/h. Similarly, the inherent safety of well-designed cars can be anticipated to be a maximum of 70 km/h in frontal impacts, and 50 km/h in side impacts. Speeds over 100 km/h can be tolerated if the infrastructure is designed to prevent frontal and side impacts. 
"Roads with no possibility of a side impact or frontal impact" are sometimes designated as Type 1 ( motorways/freeways/Autobahns ), Type 2 ("2+2 roads") or Type 3 ("2+1 roads"). These roadways have crash barriers separating opposing traffic, limited access, grade separation and prohibitions on slower and more vulnerable road users. Undivided rural roads can be quite dangerous even with speed limits that appear low by comparison. In 2010, German rural roads, which are generally limited to , had a fatality rate of 7.7 deaths per billion-travel-kilometers, higher than the 5.2 rate on urban streets (generally limited to ), and far higher than the autobahn rate of 2.0; autobahns carried 31% of motorized road traffic while accounting for 11% of Germany's traffic deaths.