Frankfurt is the meeting point of a number of major autobahns. The most important are A-3, running south from Köln and then on east to Würzburg and Nürnberg, and A-5, running south from Giessen and then on toward Heidelberg and Basel.
In Frankfurt, hidden cameras are used to catch speeders, so be sure to stick to the speed limit. Tow trucks cruise the streets in search of illegal parkers. There are many reasonably priced parking garages around the downtown area and a well-developed "park-and-ride" system with the suburban train lines. The transit map shows nearly a hundred outlying stations with a blue "P" symbol beside them, meaning there is convenient parking there.