Buick, formally the Buick Motor Division, is an American automobile division of the American manufacturer General Motors (GM). For much of its existence in the North American market, Buick has been marketed as a premium automobile brand, selling entry-level luxury vehicles. Buick holds the distinction of being the oldest active American marque of automobile, and the original Buick Motor Company was a cornerstone of the establishment of General Motors in 1908. Before the establishment of General Motors, GM founder William C. Durant previously served as Buick's general manager, while his friend Louis Chevrolet worked as a racing driver for Buick and later learned automotive design working there. In 1939 Buick also pioneered the use of turn signals, which did not appear on other car brands until almost a decade later.