Audi is a German car manufacturer that has been producing vehicles since 1909. Audi's main rival is BMW, but there are other competitors in the market such as Saab, Quattro, and Mercedes-Benz. Saab is a Swedish car manufacturer that was founded in 1945 and produces luxury vehicles. Quattro is a four-wheel drive system developed by Audi in 1980. Bahn is a German word meaning 'RAILWAY' and is often used to refer to the German RAILWAY network. Mercedes-Benz is a German car manufacturer that has been producing vehicles since 1926. BMW is a German car manufacturer that has been producing vehicles since 1916. All of these companies are rivals of Audi in the automotive industry.