23 CFR 658.13 – Length
(a) The length provisions of the STAA apply only to the following types of vehicle combinations:
(1) Truck tractor-semitrailer
(2) Truck tractor-semitrailer-trailer.
(b) The length provisions referred to in paragraph (a) of this section include the following:
(1) No State shall impose a length limitation of less than 48 feet on a semitrailer operating in a truck tractor-semitrailer combination.
(2) No State shall impose a length limitation of less than 28 feet on any semitrailer or trailer operating in a truck tractor-semitrailer-trailer combination.
(3) No State shall impose an overall length limitation on commercial vehicles operating in truck tractor-semitrailer or truck tractor-semitrailer-trailer combinations.
(4) No State shall prohibit commercial motor vehicles operating in truck tractor-semitrailer-trailer combinations.
(5) No State shall prohibit the operation of semitrailers or trailers which are 28
(c) State maximum length limits for semitrailers operating in a truck tractor-semitrailer combination and semitrailers and trailers operating in a truck tractor-semitrailer-trailer combination are subject to the following:
(1) No State shall prohibit the use of trailers or semitrailers of such dimensions as those that were in actual and lawful use in such State on December 1, 1982, as set out in appendix B of this part.
(2) If on December 1, 1982, State length limitations on a semitrailer were described in terms of the distance from the kingpin to rearmost axle, or end of semitrailer, the operation of any semitrailer that complies with that limitation must be allowed.
(d) No State shall impose a limit of less than 45 feet on the length of any bus on the NN.
(e) Specialized equipment—(1) Automobile transporters. (i) Automobile transporters are considered to be specialized equipment. As provided in § 658.5, automobile transporters may carry vehicles on the power unit behind the cab and on an over-cab rack. No State shall impose an overall length limitation of less than 65 feet on traditional automobile transporters (5th wheel located on tractor frame over rear axle(s)), including “low boys,” or less than 75 feet on stinger-steered automobile transporters. Paragraph (c) requires the States to allow operation of vehicles with the dimensions that were legal in the State on December 1, 1982.
(ii) All length provisions regarding automobile transporters are exclusive of front and rear cargo overhang. No State shall impose a front overhang limitation of less than 3 feet or a rear overhang limitation of less than 4 feet. Extendable ramps or “flippers” on automobile transporters that are used to achieve the allowable 3-foot front and 4-foot rear cargo overhangs are excluded from the measurement of vehicle length, but must be retracted when not supporting vehicles.
(iii) Drive-away saddlemount vehicle transporter combinations are considered to be specialized equipment. No State shall impose an overall length limit of less or more than 97 feet on such combinations. This provision applies to drive-away saddlemount combinations with up to three saddlemounted vehicles. Such combinations may include one fullmount. Saddlemount combinations must also comply with the applicable motor carrier safety regulations at 49 CFR parts 390-399.
(2) Boat transporters. (i) Boat transporters are considered to be specialized equipment. As provided for automobile transporters in § 658.5, boat transporters may carry boats on the power unit so long as the length and width restrictions of the vehicles and load are not exceeded. No State shall impose an overall length limitation of less than 65 feet on traditional boat transporters (fifth wheel located on tractor frame over rear axle(s), including “low boys,” or less than 75 feet on stinger-steered boat transporters. In addition, no State shall impose an overall length limitation of less than 65 feet on truck-trailer boat transporters. Paragraph (c) of this section requires the States to allow operation of vehicles with the dimensions that were legal in the State on December 1, 1982.
(ii) All length provisions regarding boat transporters are exclusive of front and rear overhang. Further, no State shall impose a front overhang limitation of less than three (3) feet nor a rearmost overhang limitation of less than four (4) feet.
(3) Truck-tractor semitrailer-semitrailer. (i) Truck-tractor semitrailer-semitrailer combination vehicles are considered to be specialized equipment. No State shall impose a length limitation of less than 28 feet on any semitrailer or 28
(ii) The B-train assembly is excluded from the measurement of trailer length when used between the first and second trailer of a truck-tractor semitrailer-semitrailer combination vehicle. However, when there is no semitrailer mounted to the B-train assembly, it will be included in the length measurement of the semitrailer, the length limitation in this case being 48 feet, or longer if grandfathered.
(4) Maxi-cube vehicle. No State shall impose a length limit on a maxi-cube vehicle, as defined in § 658.5 of this part, of less than 34 feet on either cargo box, excluding drawbar or hitching device; 60 feet on the distance from the front of the first to the rear of the second cargo box, including the space between the cargo boxes; or 65 feet on the overall length of the combination, including the space between the cargo boxes. The measurement for compliance with the 60- and 65-foot distance shall include the actual distance between cargo boxes, measured along the centerline of the drawbar or hitching device. For maxi-cubes with an adjustable length drawbar or hitching device, the 60- and 65-foot distances shall be measured with a drawbar spacing of not more than 27 inches. The drawbar may be temporarily extended beyond that distance to maneuver or load the vehicle.
(5) Beverage semitrailer. (i) A beverage semitrailer is specialized equipment if it has an upper coupler plate that extends beyond the front of the semitrailer, but not beyond its swing radius, as measured from the center line of the kingpin to a front corner of the semitrailer, which cannot be used for carrying cargo other than the structure of the semitrailer, and with the center line of the kingpin not more than 28 feet from the rear of the semitrailer (exclusive of rear-mounted devices not measured in determining semitrailer length). No State shall impose an overall length limit on such vehicles when operating in a truck tractor-beverage semitrailer or truck tractor-beverage semitrailer-beverage trailer combination on the NN.
(ii) The beverage trailer referred to in paragraph (e)(5)(i) of this section means a beverage semitrailer and converter dolly. Converter dolly has the same meaning as in 49 CFR 393.5.
(iii) Truck tractor-beverage semitrailer combinations shall have the same access to points of loading and unloading as 28-foot semitrailers (28.5-foot where allowed by § 658.13) in 23 CFR 658.19.
(6) Munitions carriers using dromedary equipment. A truck tractor equipped with a dromedary unit operating in combination with a semitrailer is considered to be specialized equipment, providing the combination is 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. No State shall impose an overall length limitation of less than 75 feet on the combination while in operation.
(f) A truck tractor containing a dromedary box, deck, or plate in legal operation on December 1, 1982, shall be permitted to continue to operate, notwithstanding its cargo carrying capacity, throughout its useful life. Proof of such legal operation on December 1, 1982, shall rest upon the operator of the equipment.
(g) No State shall impose a limitation of less than 46 feet on the distance from the kingpin to the center of the rear axle on trailers or semitrailers used exclusively or primarily to transport vehicles in connection with motorsports competition events.
(h) Truck-tractors, pulling 2 trailers or semitrailers, used to transport custom harvester equipment during harvest months within the State of Nebraska may not exceed 81 feet 6 inches.