Abstract: A folding automobile storage deck for semitrailers which allows a semitrailer so equipped to be used for either automobile or general freight transportation. The deck comprises both folding and swivel deck sections which are longitudinally divided, and which may be disposed either in a vertical storage position, the general freight carrying mode, or horizontally deployed and connected together when automobiles are to be carried. The swivel deck section is designed so that all points of attachment between the deck and the sidewalls, except the point at which the deck is swiveled may be disconnected and the ends of the deck support members thus disconnected telescoped into the deck section, thereby allowing the deck to be swiveled up or down as necessary during the process of automobile loading or unloading and reconnected when the process is completed.