California Code, Vehicle Code - VEH § 29002

Every fifth wheel mechanism, including adapters, shall be equipped with a locking device which will not permit the upper and lower halves to be separated without the operation of a positive manual release. The manual release shall be designed, installed, and maintained so that it cannot be accidentally operated. Automatic locking devices on fifth wheels designed and constructed to be readily separable are required on any vehicle first required to be registered in this state after January 1, 1954.