Direction North, South, East
The A5 is passing Karlsruhe and connects it to Frankfurt am Main, Basel, Stuttgart and other cities. The best ramp is Karlsruhe-Durlach. Take the tram 1, 2, S4 or S5 to Weinweg. There is a gas station close by where you can ask people, but you can also stand directly on the ramp, waving a sign or a thumb. The hard shoulder serves enough space for anyone to stop.
In the town center, between Europaplatz and Marktplatz there are a some info terminals called blue spots where you can see town maps, send emails and surf the internet for free.
Public transport is quite good. The tram lines go into all the neighbouring towns. Within the city, they go all night at weekends. Fares are about 2 EUR per trip. Tickets are checked quite often, even at night.