I live in Germany and drive in Germany several times per week most weeks. I’m just back yesterday from a trip to Paris, and I’ve made several other long trips across and around Germany. I find that in the cities, Germans are pretty good drivers. They pay attention and are not as likely as Americans or some others to do seemingly irrational or unpredictable things.
Driving on the Autobahns is a different story, however. Autobahn driving is relatively stressful and requires absolute attention and vigilance at all times. As another poster mentioned, pretty much everyone is driving at different rates of speed. This means one is constantly overtaking or being overtaken. There are MANY trucks on the highway, plus the speed limit, where there is a marked limit, changes frequently, also. Forget trying to use cruise control, as the speed differences and traffic often make it impossible to maintain a constant speed for any reasonable length of time.
Pretty much every road in Germany is under construction at present, so expect to be stuck in at least one world-class traffic back-up on the Autobahn, which is known as a Stau.
The Germans do tailgate massively, and they will cut in front of you, or across you to race to an exit (Ausfahrt) with much less clearance than is commonly left in the US. While another poster mentioned that one should never pass on the right, I have seen it done and witnessed someone in a Porsche do it and avoid death by inches just last week. The Germans will do things commonly on the Autobahns that would earn one an aggressive driving citation on the Beltway around DC or elsewhere in Virginia or Maryland.
While there are still lots of places with unlimited speed, if you are driving over 130 kph (80 mph) and you have an accident, it is automatically your fault. Another poster mentioned cameras. They are known as Blitzers and they are ubiquitous. If you see a flash either ahead of you or in your mirror, you can expect a ticket in the mail shortly.
There are lots of gas stations and places to stop for food along the Autobahns. I’ve never had a hard time getting gas. Gas averages about Euro 1.44 per litre for regular, which works out to about $7.80 per US gallon.
The Autobahns around Munich are some of the best I’ve been on in Germany. I found myself moving comfortably with traffic at nearly 100 mph last time I was through there on my way to Siegsdorf for some fly fishing.
The signage is pretty good, with clearly named and numbered exits. Two things that I’ve found to be different are that there are seldom signs that identify what road one is currently driving on – no A5 or A3 signs along the route, as we have in the US. This is an issue because of the second strange thing – sometimes you have to exit from the road you are on to stay on the road you are on. Whereas the main through lanes for a highway in the US most often are on the left, in several instances the main Autobahn splits off to the right and one can inadvertantly end up on another highway if not paying attention. Sometimes it is a pretty long time until you see a sign that tells you that you are now on A67 instead of A5, for instance.
Use an online mapping service to get point-to-point directions to and from your destination.
Have a good trip, and above all, stay alert.