#1 It's Actually Very Safe
The Autobahn is very well maintained and constructed. the Autobahn is far safer than freeways in the U.S. because of all the added safety features and the fact that roads and bridges in the U.S. go without maintenance for decades. Fatalities on the German Autobahn are at 4.3 per hundred thousand while in the United States that number is 11.5 for every hundred thousand drivers. You'll get fined heavily if you run out of gas on the highway so there are stations every 30 miles and telephones placed every 2 miles.
#2 The Left Lane Is The Fast Lane… Period
As in the US, the left lane is for passing only. You'll get arrested for doddling along in that lane and most cars are traveling at about 150mph when passing in the fast lane. You have to keep up with the flow of traffic because if you speed up and tailgate, the fine is $500. with a suspended license and ban from the Autobahn for 3 months. The setup of the Autobahn is surprisingly built around safety, in spite of the intense speeds. Given that, one must never pass on the right. It is most certainly illegal.