I believe it refers to cars which actually went into production, ie more than one was made. If there's just one crazily incredible car made, with lots of aspects and facilities which are unlikely to be needed by a normal driver, it's a "concept car". However, some cars are pretty advanced, fast, etc and they actually do go into production (ie they are made in a factory for people to buy). Then they become a "production car".
Student or Learner