The autobahns also have a minimum speed requirement: Vehicles must be able to maintain 60 kph (37 mph) on flat terrain. Some stretches have minimum speeds of 90 kph (56 mph) or 110 kph (68 mph) in certain lanes.

Autobahn Germany: History of Speed Limits

The Nazi government passed the Road Traffic Act in 1934, limiting speeds to 60 kph (37 mph) in urban areas but setting no limit for rural roads or autobahns. In 1939, responding to fuel shortages, the government lowered the limit to 40 kph (25 mph) in town and 80 kph (50 mph) on all other roads. The West German government did away with all federal speed limits in 1952, ceding authority to the individual states. An appalling rise in traffic deaths led to a country-wide speed limit of 100 kph (62 mph) in 1972, though autobahns remained unrestricted.

In December 1973, the oil crisis prompted the West German government to set an autobahn speed limit of 100 kph (62 mph). The measure was instantly unpopular and was repealed the following March. The advisory speed limit was adopted in 1978. Legislation to set a hard speed limit (usually 130 kph/81 mph) comes up on a fairly regular basis and is always defeated.

Building (and Maintaining) For Speed

If you live in places where road construction and/or maintenance leaves something to be desired—Los Angeles and Detroit come to mind—German Autobahns are designed for high-speed driving. Freeze-resistant concrete or asphalt is laid over a heavy roadbed, with a combined depth in the neighborhood of 30 inches. Curves are gentle and slightly banked, and grades are limited to 4 percent. The roadways are split with a center median that features dual guardrails or concrete barriers. The routes generally avoid large cities, which are accessed by spur roads.

At high speeds, pavement irregularities can become fatal obstacles, so Germany's autobahn roadways receive frequent and detailed inspection. Repair generally involves replacing sections of the roadway rather than patching, which sounds like a dream here in the U.S.

Autobahn Germany: What's It Really Like to Drive?

Driving the high-speed sections of the autobahn in Germany is not a matter of simply flooring the accelerator and watching the speedo climb. Speed limits come and go, especially near cities, and high-speed sections are punctuated by speed-limited sections enforced by photo radar. Lane discipline is strict (though not as well observed as you might expect, especially nowadays), tailgating is frowned upon, and passing on the right is strictly forbidden.

When driving on an unrestricted section of autobahn in Germany, you must look far down the road—you may be bombing down the highway at 180 kph (112 mph) when a car doing 130 pulls into the left lane in front of you to pass a truck limited to 80 kph. You also have to keep one eye glued to the mirror for Porsches and big Mercedes coming up fast from behind—they really do seem to materialize out of thin air. While the Germans are fanatical about road inspection, there's no guarantee they will find a pothole before you do, so you also need to keep a careful eye on the road condition ahead

The end result is that driving fast on German autobahns can be an exhausting experience, a sharp contrast from the more relaxed driving style common on American highways. The concentration you must exert rises exponentially with speed; it's an adrenaline rush for sure, but once you've tried it, you'll understand why so many autobahn drivers in Germany cruise at more sedate speeds—or just take the train.