By the 1930s, most of the mechanical technology used in today's automobiles had been invented, although some things were later "re-invented", and credited to someone else. For example, front-wheel drive was re-introduced by André Citroën with the launch of the Traction Avant in 1934, though it had appeared several years earlier in road cars made by Alvis and Cord, and in racing cars by Miller (and may have appeared as early as 1897).but not put in production until appearing on the low-volume Mercedes-Benz 380 in 1933, which prodded American makers to use it more widely.In 1930, the number of auto manufacturers declined sharply as the industry consolidated and matured, thanks in part to the effects of the Great Depression.