The BVG has subsidiaries, is a member of various associations, and works in partnership with a range of companies. BVG subsidiary URBANIS GmbH is responsible for letting stores and kiosks in Berlin underground stations, creating hundreds of jobs for tenants in the process. Another BVG subsidiary is Berlin Transport (BT), whose almost 1,800 bus and underground drivers help to ensure the smooth running of operations. One key partner of the BVG is Deutsche Bahn AG (DB), which operates S-Bahn and local trains in Berlin and Brandenburg. Together, they are part of the Berlin-Brandenburg Public Transport Network (VBB), a common fare area enabling passengers to change between services run by different operators without problems. The BVG is also a member of the Association of German Transport Companies (VDV) and the International Association of Public Transport (UITP). For ride sharing services, the BVG cooperates with its partners car2go, DriveNow, Multicity, Greenwheels, and Call a Bike.