Most of Bremen is covered by trams. About 10 tram lines are run by the Verkehrsverbund Bremen / Niedersachsen, the BSAG.
The BSAG also operates quite many regular bus lines. In front of the Hauptbahnhof and near the City Hall, there are main hubs. For more information about lines and timetables, have a look at the website of the BSAG,
www.bsag.de.