General Motors designer Harley Earl is generally credited with inventing the concept car, and did much to popularize it through its traveling Motorama shows of the 1950s. Concept cars never go into production directly; in modern times all would have to undergo many changes before the design is finalized for the sake of practicality, safety and cost. A "production-intent" vehicle, as opposed to a concept vehicle, serves this purpose. They are also known as prototype cars, but should not be confused with prototype race cars such as the Le Mans Prototype.