Model changeover and design change and the impact of Alfred P. Sloan on the industry

A Ford Taurus, a modern family car which has gone through a number of changes.

Cars are not merely continually perfected mechanical contrivances; since the 1920s nearly all have been mass-produced to meet a market, so marketing plans and manufacture to meet them have often dominated automobile design. It was Alfred P. Sloan who established the idea of different makes of cars produced by one firm, so that buyers could "move up" as their fortunes improved. The makes shared parts with one another so that the larger production volume resulted in lower costs for each price range. For example, in the 1950s, Chevrolet shared hood, doors, roof, and windows with Pontiac; the LaSalle of the 1930s, sold by Cadillac, used the cheaper mechanical parts made by the Oldsmobile division.