2023 Delaware Code › Title 21 - Motor Vehicles › Chapter 45. SIZE AND WEIGHT OF VEHICLES AND LOADS › § 4503. Size and weight of vehicles on interstate highways; size of vehicles on federal-aid primary system highways and United States numbered routes.

§ 4503. Size and weight of vehicles on interstate highways; size of vehicles on federal-aid primary system highways and United States numbered routes.
(a) No person shall drive or move or, being the owner, cause or knowingly permit to be driven or moved on any interstate highway, federal-aid primary system highway, or United States numbered route, unless otherwise posted, any vehicle or combination of vehicles having a size or weight in excess of that permitted by this section. Provided, however, that such weight limitations and restrictions listed in this section apply only to the interstate highway; weight limitations and restrictions for federal-aid primary system highways and United States numbered routes shall be as listed in § 4502 of this title.
(b) (1) No vehicle, including any load thereon, shall exceed a height of 13 feet, 6 inches.
(2) The maximum length of a semitrailer, including any load thereon, exclusive of truck tractor size shall be 53 feet.
(3) The maximum length of a trailer or semitrailer in a truck tractor-semitrailer-trailer combination, including any load thereon, exclusive of tractor size shall be 29 feet.
(4) Buses shall not exceed 45 feet in length.
(5) Single vehicles including the load thereon shall not exceed 40 feet in length.
(6) No vehicle including any load thereon shall exceed a total outside width of 102 inches, exclusive of safety equipment, which shall not extend more than 3 inches wider on each side of the vehicle, or as shall be authorized by the Delaware Secretary of Public Safety.
(7) Notwithstanding paragraph (b)(5) or (6) of this section:
a. No recreational vehicle, including any load or truck camper thereon or any camping trailer, recreational trailer or park trailer attached thereto, shall exceed a total outside width of 102 inches, exclusive of any safety equipment, which shall not extend beyond the federal motor vehicle safety standards for such equipment, or appurtenances such as awnings and lights which are integral to the construction of the vehicle, installed by the vehicle's manufacturer or dealer, and do not extend more than 6 inches wider on each side of the vehicle;
b. No single recreational vehicle, including any load or truck camper thereon, shall exceed 45 feet in length; and
c. No combination of a recreational vehicle with any vehicle, including the load thereon, nor any combination of any motor vehicle with any camping trailer, recreational trailer or park trailer attached thereto, shall exceed 65 feet in length.
(c) (1) Each weight stated in this section shall apply only to interstate highways and is a total gross weight which includes the weight of the vehicle, including load thereon and any enforcement tolerance applicable thereto.
(2) It shall be unlawful for the gross weight on any 1 axle to exceed 20,000 pounds.
(3) It shall be unlawful for the gross weight on any tandem or coupled axles to exceed 34,000 pounds.
(4) It shall be unlawful for the maximum gross weight for any vehicle to exceed the sum of the allowed axle weight for the number of axles actually bearing their full share of the weight upon the pavement or the smallest weight as calculated hereunder:
a. The gross weight of any vehicle or combination of vehicles shall not exceed the weights stated hereunder:
2 axles — 40,000 lbs.
3 axles — 54,000 lbs.
4 axles — 74,000 lbs.
5 axles — 80,000 lbs.
b. The maximum gross weight of any vehicle or combination of vehicles on a group of 2 or more consecutive axles shall not exceed the weight as calculated by this formula:
W=500LN/N-1+12N+36
For purposes of this subsection, W equals overall gross weight on any group of 2 or more consecutive axles to the nearest 500 pounds, L equals the distance in feet between the extreme of any group of 2 or more consecutive axles, and N equals the number of axles in the group under consideration except that 2 consecutive sets of tandem axles may carry a gross load of 34,000 pounds each, whenever the overall distance between the first and last axle of the consecutive sets is 36 feet or more.
(d) The Delaware Secretary of Transportation may, on the basis of engineering and traffic investigations, determine that certain interstate highways, federal-aid primary system highways, and United States numbered routes cannot accommodate vehicles, otherwise permitted under this section, and may thereafter prohibit operation of such vehicles on the interstate highways, federal-aid primary system highways, and United States numbered routes so designated.
(e) The provisions of this section do not apply to the following vehicles when such vehicles are being operated on interstate highways and United States numbered routes; provided, however, that the liability for damages caused by any vehicle operated under this provision shall be borne by the owner of said vehicle:
(1) Fire apparatus owned or used by an organized fire company.
(2) Farm equipment being temporarily operated, moved or transported on a highway. This provision only applies to farmers engaged in their agricultural related practices.
(f) Any vehicle subject to this subpart that utilizes an auxiliary power or idle reduction technology unit in order to promote reduction of fuel use and emissions because of engine idling, may be allowed up to an additional 400 lbs. total in gross, axle, tandem, or bridge formula weight limits.
(1) To be eligible for this exception, the operator of the vehicle must be able to prove:
a. By written certification, the weight of the APU; and
b. By demonstration or certification, that the idle reduction technology is fully functional.
(2) Certification of the weight of the APU must be available to law-enforcement officers if the vehicle is found in violation of applicable weight laws. The additional weight allowed cannot exceed 400 lbs. or the weight certified, whichever is less.
(g) The State hereby adopts federal commercial vehicle size limit exemptions for vehicles operating on interstate highways, federal-aid primary system highways, and United States numbered routes within the State as directed in 49 U.S.C. § 31111 and 49 U.S.C. § 31113 as amended.
(h) The State hereby adopts federal interstate weight limit exemptions for vehicles operating on interstate highways within the State as directed in 23 U.S.C. § 127 as amended.
64 Del. Laws, c. 207, §  5;  67 Del. Laws, c. 345, §§  1, 2;  68 Del. Laws, c. 281, §  1;  69 Del. Laws, c. 73, §  1;  70 Del. Laws, c. 186, §  1;  70 Del. Laws, c. 259, §§  1, 2;  74 Del. Laws, c. 133, §  2;  77 Del. Laws, c. 124, §  1;  82 Del. Laws, c. 93, § 4;