Bundesautobahn 391 (translates from German as Federal Motorway 391, short form Autobahn 391, abbreviated as BAB 391 or A 391) is an autobahn in Braunschweig, also known as the Braunschweiger Westtangente. Its purpose is to connect the A 2 with the A 39, passing the city of Braunschweig on the western side.