TRAFFIC
The roads are in general in very good condition. However the traffic is no better than in the States. You will find smaller cars, more diesel vehicles, fewer trucks and vans and (somewhat depending on the area) aggressive drivers. Be prepared to be passed by cars that drive at 140 miles/hour on the infamous "Autobahn".
LICENSE
If you already have a driver's license which is valid in an EC country, then that is all you need, but it must be presented for verification at the Führersheinstelle (Drivers License office).
With only a few other exceptions, you must obtain a German license within 12 months of first becoming a permanent resident in Germany (i.e. "Anmeldung" - registering at the city hall, not the equivalent of a American "Permanent Residency"). Prior to that time, you can use a valid license from another country to drive vehicles of the category for which the foreign driving license has been issued.
Although a foreign driving license entitles its holder to drive motor vehicles only for a period of one year after the establishment of the permanent residence, it may still be exchanged for a German license within the two years following this period.
The applicant will receive the German driving license for the category of motor vehicle which he/she was entitled to drive according to his/her foreign driving license, provided that he/she passes a theoretical and practical test for this category. Training in a driving school as required for the first acquisition of a driving license is not necessary