Automobile transporters. Any vehicle combination designed and used specifically for the transport of assembled highway vehicles, including truck camper units.

Beverage semitrailer. A van-type, drop-frame semitrailer designed and used specifically for the transport and delivery of bottled or canned beverages (i.e., liquids for drinking, including water) which has side-only access for loading and unloading this commodity. Semitrailer has the same meaning as in 49 CFR 390.5.

Boat transporters. Any vehicle combination designed and used specifically to transport assembled boats and boat hulls. Boats may be partially disassembled to facilitate transporting.

Bridge gross weight formula. The standard specifying the relationship between axle (or groups of axles) spacing and the gross weight that (those) axle(s) may carry expressed by the formula:

Cargo-carrying unit. As used in this part, cargo-carrying unit means any portion of a commercial motor vehicle (CMV) combination (other than a truck tractor) used for the carrying of cargo, including a trailer, semitrailer, or the cargo-carrying section of a single-unit truck. The length of the cargo carrying units of a CMV with two or more such units is measured from the front of the first unit to the rear of the last [including the hitch(es) between the units].

Commercial motor vehicle. For purposes of this regulation, a motor vehicle designed or regularly used to carry freight, merchandise, or more than ten passengers, whether loaded or empty, including buses, but not including vehicles used for vanpools, or recreational vehicles operating under their own power.

Drive-away saddlemount vehicle transporter combination. The term drive-away saddlemount vehicle transporter combination means a vehicle combination designed and specifically used to tow up to 3 trucks or truck tractors, each connected by a saddle to the frame or fifth wheel of the forward vehicle of the truck tractor in front of it. Such combinations may include up to one fullmount.

Dromedary unit. A box, deck, or plate mounted behind the cab and forward of the fifth wheel on the frame of the power unit of a truck tractor-semitrailer combination.

Federal-aid Primary System. The Federal-aid Highway System of rural arterials and their extensions into or through urban areas in existence on June 1, 1991, as described in 23 U.S.C. 103(b) in effect at that time.

Fullmount. A fullmount is a smaller vehicle mounted completely on the frame of either the first or last vehicle in a saddlemount combination.

Interstate System. The National System of Interstate and Defense Highways described in sections 103(e) and 139(a) of Title 23, U.S.C. For the purpose of this regulation this system includes toll roads designated as Interstate.

Length exclusive devices. Devices excluded from the measurement of vehicle length. Such devices shall not be designed or used to carry cargo.

Longer combination vehicle (LCV). As used in this part, longer combination vehicle means any combination of a truck tractor and two or more trailers or semitrailers which operates on the Interstate System at a gross vehicle weight greater than 80,000 pounds.

Maxi-cube vehicle. A maxi-cube vehicle is a combination vehicle consisting of a power unit and a trailing unit, both of which are designed to carry cargo. The power unit is a nonarticulated truck with one or more drive axles that carries either a detachable or a permanently attached cargo box. The trailing unit is a trailer or semitrailer with a cargo box so designed that the power unit may be loaded and unloaded through the trailing unit. Neither cargo box shall exceed 34 feet in length, excluding drawbar or hitching device; the distance from the front of the first to the rear of the second cargo box shall not exceed 60 feet, including the space between the cargo boxes; and the overall length of the combination vehicle shall not exceed 65 feet, including the space between the cargo boxes.

Motor carrier of passengers. As used in this part, a motor carrier of passengers is a common, contract, or private carrier using a bus to provide commercial transportation of passengers. Bus has the same meaning as in 49 CFR 390.5.

National Network (NN). The composite of the individual network of highways from each State on which vehicles authorized by the provisions of the STAA are allowed to operate. The network in each State includes the Interstate System, exclusive of those portions excepted under § 658.11(f) or deleted under § 658.11(d), and those portions of the Federal-aid Primary System in existence on June 1, 1991, set out by the FHWA in appendix A to this part.

Nondivisible load or vehicle.

Over-the-road bus. The term over-the-road bus means a bus characterized by an elevated passenger deck located over a baggage compartment, and typically operating on the Interstate System or roads previously designated as making up the Federal-aid Primary System.

Saddlemount combination. A saddlemount combination is a combination of vehicles in which a truck or truck tractor tows one or more trucks or truck tractors, each connected by a saddle to the frame or fifth wheel of the vehicle in front of it. The saddle is a mechanism that connects the front axle of the towed vehicle to the frame or fifth wheel of the vehicle in front and functions like a fifth wheel kingpin connection. When two vehicles are towed in this manner the combination is called a double saddlemount combination. When three vehicles are towed in this manner, the combination is called a triple saddlemount combination.

Single axle weight. The total weight transmitted to the road by all wheels whose centers may be included between two parallel transverse vertical planes 40 inches apart, extending across the full width of the vehicle. The Federal single axle weight limit on the Interstate System is 20,000 pounds.

Special mobile equipment. Every self-propelled vehicle not designed or used primarily for the transportation of persons or property and incidentally operated or moved over the highways, including military equipment, farm equipment, implements of husbandry, road construction or maintenance machinery, and emergency apparatus which includes fire and police emergency equipment. This list is partial and not exclusive of such other vehicles as may fall within the general terms of this definition.

Stinger-steered combination. A truck tractor semitrailer wherein the fifth wheel is located on a drop frame located behind and below the rear-most axle of the power unit.

Tandem axle weight. The total weight transmitted to the road by two or more consecutive axles whose centers may be included between parallel transverse vertical planes spaced more than 40 inches and not more than 96 inches apart, extending across the full width of the vehicle. The Federal tandem axle weight limit on the Interstate System is 34,000 pounds.

Terminal. The term terminal as used in this regulation means, at a minimum, any location where:

Freight either originates, terminates, or is handled in the transportation process; or

Commercial motor carriers maintain operating facilities.

Tractor or Truck tractor. The noncargo carrying power unit that operates in combination with a semitrailer or trailer, except that a truck tractor and semitrailer engaged in the transportation of automobiles may transport motor vehicles on part of the power unit, and a truck tractor equipped with a dromedary unit operating in combination with a semitrailer transporting Class 1 explosives and/or any munitions related security material as specified by the U.S. Department of Defense in compliance with 49 CFR 177.835 may use the dromedary unit to carry a portion of the cargo.

Truck-tractor semitrailer-semitrailer. In a truck-tractor semitrailer-semitrailer combination vehicle, the two trailing units are connected with a “B-train” assembly. The B-train assembly is a rigid frame extension attached to the rear frame of a first semitrailer which allows for a fifth wheel connection point for the second semitrailer. This combination has one less articulation point than the conventional “A dolly” connected truck-tractor semitrailer-trailer combination.

Truck-trailer boat transporter. A boat transporter combination consisting of a straight truck towing a trailer using typically a ball and socket connection. The trailer axle(s) is located substantially at the trailer center of gravity (rather than the rear of the trailer) but so as to maintain a downward force on the trailer tongue.

Width exclusive devices. Devices excluded from the measurement of vehicle width. Such devices shall not be designed or used to carry cargo.