I found the autobahn utterly nerve-wracking to drive on.

In the US, on an interstate, the MPH spread around the speed limit is probably -20 to +20 (i.e. limit is 75, slowest cars are at 55, fastest at 95)

In Germany, on autobahns, you have speed ratios of up to 2x. You have to constantly be 110% aware of every vehicle within 1/4 mile of you, because you could either be closing in the much slower vehicle in front of you, or suddenly approached and passed by a much faster vehicle from behind.

>You have to constantly be 110% aware of every vehicle within 1/4 mile of you,

Not such a terrible thing honestly...

Personally, I find the lack of predictability on US interstates is much riskier. I'm pretty sure the accident statistics back this up too.

Absolutely. I was stationed in Germany for 3 years while I was in the Army. You could be in the left lane of the Autobahn, doing 90+ passing a truck, and suddenly a Ferrari that wasn't there 5 seconds ago is right behind you, flashing its headlights demanding you get out of the way (apparently you're supposed to merge into the side of a semi).