If you go to gas station on an autobahn, pay attention to the signs that show the truck side and the passenger car side of the station. The convenience store and the restaurants on such places are also separated for trucks and cars.

And just so you know. At all Aral stations, they'll ask if you have a certain "Payback Karte". Just say no. BTW, it's a points system adopted by many (major) business here in Germany.