N.Y. Comp. Codes R. & Regs. tit. 17, § 8000.7 – Authorized vehicles.

(a) The following vehicles and combinations of vehicles which otherwise conform to legal dimensions and weights are authorized to operate on all qualifying highways and all access highways unless otherwise specified in Parts 8000 and 8100 of these Regulations:
1. (1) A tractor-semitrailer-trailer combination where neither the semitrailer nor the trailer exceeds 28½ feet in length, and a width not to exceed 102 inches.
2. (2) A tractor-semitrailer combination with an overall length greater than 65 feet, in which the semitrailer does not exceed 48 feet in length, and width of not more than 102 inches.
3. (3) A combination of an automotive powered cab and truck chassis being used to tow three such additional vehicles in triple saddle-mount fashion each mounted upon a device designed and constructed so as to be readily dismountable and which performs the function of a conventional fifth-wheel, so that while all the wheels of the towing power chassis touch the roadway, only the wheels on the rear axle on each of the towed vehicles are in contact with the roadway.
4. (4) A stinger-steered automobile transporter of a total length not greater than 75 feet exclusive of an overhang of not more than three feet on the front and four feet on the rear of the vehicle configured as a semitrialer combination wherein the fifth wheel is located on a drop frame located behind and below the rear-most axle of the power unit.
5. (5) A "maxi-cube" vehicle consisting of a truck tracker combined with a semitrailer and a seperable cargo carrying unit which is designed to be loaded through the semitrailer, except that the entire combination shall not exceed 65 feet in length and the separable cargo carrying unit shall not exceed 34 feet in length.
(b) A tractor-semitrailer combination in which the semitrailer is of a length greater than 48 feet but not greater than 53 feet, provided the distance between the kingpin of the semitrailer and the centerline of the rear axle or rear axle group does not exceed 41 feet, and which is equipped with a rear-end protective device of substantial construction consisting of a continuous lateral beam extending to within four inches of the lateral extremities of the semitrailer and located not more than 22 inches from the surface as measured with the vehicle empty and on a level surface, otherwise conforming to legal dimensions and weights, is authorized to operate on all qualifying highways and access highways outside of the City of New York, unless otherwise specified in Parts 8000 and 8100 of these Regulations, and, in addition, may operate on that portion of IR 95 which connects IR 287 with IR 295; on that portion of IR 295 which portion of IR 295 which connects IR 95 with IR 495; and that portion of IR 495 between IR 95 and the Nassau-Queens county line, all in New York City.