If you are a real piston head then you really have to rent a car for your trip to Bremen. Car hire firms are located throughout the city, whether it be at Bremen Airport, Bremen Nord/Aumund, Bremen Central Railway Station, Bremen Habenhausen, Bremen Downtown, Bremen East, Bremen Osterholz, Bremen Vegesack, Bremen North, Bremen Lindenstr and elsewhere. As such, you can collect your rental car wherever is best for you. Moreover, Bremen is known for its safe car parks, so you won't need to worry about where you leave the car.