The Audi A4 is a compact executive car produced since late 1994 by the German car manufacturer Audi, a division of the Volkswagen Group. The A4 has has been built in four generations and is based on Volkswagen's B platform. The first generation A4 succeeded the Audi 80. The automaker's internal numbering treats the A4 as a continuation of the Audi 80 lineage, with the initial A4 designated as the B5-series, followed by the B6, B7, and the current B8. The Audi A4 automobile layout consists of a longitudinally oriented engine at the front, with transaxle-type transmissions mounted at the rear of the engine. The cars are front-wheel drive, or on some models, "quattro" four-wheel drive. The A4 is available as a saloon/sedan and estate/wagon. The second (B6) and third generations (B7) of the A4 also had a convertible version.