On and after January 1, 1971 every trailer except a semitrailer, while being drawn upon the public highways of this State, shall be attached to the vehicle drawing the same by a device of a type approved by the Commissioner of Motor Vehicles. Accordingly, the commissioner establishes this Part relating to vehicle connecting arrangements used for drawing trailers by mechanical power on the public highways. This Part is not for those arrangements used for drawing another vehicle by means of a tow truck or wrecker or a semitrailer made into a full trailer by means of a converter dolly.
N.Y. Comp. Codes R. & Regs. Tit. 15 § 57.1