And I'll add to what proxim202 said - speed limits abound in Germany and not all of the Autobahn is without a posted speed limit. German drivers know the limits of their automobiles - not everybody on the Autobahn drives 200+ km/h because not all of their vehicles are built for that. Along the same lines - keeping to the right is STRICTLY enforced.
Contrast that with the stretch of I-78 near where I live. We had four accidents with fatalities last month. Speed was a factor in all four even though this is a "targeted enforcement area" with a speed limit of 55 mph. Traffic routinely moves at 70 mph here.
I avoid I-78 because of the "I'm in a hurry so you better get out of my way" mentality that pervades most of the drivers here. You see none of that in Germany. JMHO