23 U.S.C. § 127 — Vehicle weight limitations—Interstate System

(a) In General. (1) The federal government must cut a state's highway funding in half for a fiscal year if the state lets trucks use the Dwight D. Eisenhower System of Interstate and Defense Highways while weighing more than these limits: 20,000 pounds on any one axle (counting enforcement tolerances), 34,000 pounds on a tandem axle (counting tolerances), or, for combination vehicles with five or more axles, a gross weight of at least 80,000 pounds. (2) A state's maximum allowed weight for Interstate vehicles is: 20,000 pounds on one axle (with tolerances), 34,000 pounds on a tandem axle (with tolerances), and an overall weight for any group of two or more consecutive axles set by a formula. The formula uses three values: W is the allowed overall weight for the axle group, rounded to the nearest 500 pounds; L is the distance in feet between the first and last axle in the group; and N is the number of axles in the group. The statutory text of the exact equation is garbled by OCR artifacts, but it works by taking the 500-pound unit, applying it across the axle spacing (L) and axle count (N), and adding a fixed allowance based on N — the larger the axle group and the more spread out it is, the more weight it can carry. There is one exception to this formula: two separate tandem-axle sets can each carry 34,000 pounds if the distance between the first and last axle of the two sets is either 36 feet or more, or (for a vehicle hauling a tank trailer, dump trailer, or ocean transport container before September 1, 1989) 30 feet or more. Even so, the overall gross weight can never exceed 80,000 pounds (with tolerances), except for: vehicles on Interstate 29 between Sioux City, Iowa and the Iowa–South Dakota border, or on Interstate 129 between Sioux City and the Iowa–Nebraska border; vehicles and loads that can't easily be taken apart or divided and that have a special state permit; or vehicles that could legally use that state's public highways under the state's own weight laws in effect on July 1, 1956 (or, for axle-group weight specifically, laws in effect on the date the Federal-Aid Highway Amendments of 1974 were enacted) — whichever of these produces the higher allowed weight. This 1956-law exception does not apply to a vehicle made up of a motor vehicle hauling a tank trailer, dump trailer, or ocean transport container on or after September 1, 1989. (3) If money is withheld from a state's apportionment under this subsection and never released and spent within the availability period set in section 118(b), that withheld money is lost for good (it lapses). (4) This section does not block funding to a state that allows other vehicles or combinations — besides the "longer combination vehicles" covered by subsection (d) — that the state determines could legally operate there on July 1, 1956 (or, for axle-group weight, on the date the Federal-Aid Highway Amendments of 1974 were enacted). (5)–(11) A series of state-specific baseline dates and rules replace the general July 1, 1956 date or add extra allowances: Hawaii uses its laws as of February 1, 1960. Colorado treats a vehicle built to carry two or more precast concrete panels as carrying a load that can't be divided. Michigan uses its laws as of May 1, 1982. Maryland uses its laws as of June 1, 1993. Louisiana may issue special permits letting sugarcane-hauling vehicles weigh up to 100,000 pounds during harvest season, for no more than 100 days a year. On Interstate Routes 89, 93, and 95 in New Hampshire: (A) the state's own weight laws for non-Interstate highways, as they stood on January 1, 1987, apply instead of this subsection's normal limits; and (B) starting June 30, 2016, a truck-tractor and dump-trailer combination with 6 or more axles may weigh up to 99,000 pounds if the distance between its outermost axles (not counting the steering axle) is 28 feet or more. On all Interstate highways in Maine, and separately in Vermont, each state's own weight laws for its other state highways apply instead of this subsection's normal limits. (12) Heavy-duty vehicles. A heavy-duty vehicle equipped with technology that lets its engine idle without wasting fuel or adding emissions may weigh more than the normal gross-vehicle and axle limits, by whatever extra weight the idle-reduction equipment adds — up to a maximum increase of 550 pounds. If a regulator or law-enforcement officer asks, the vehicle's operator must prove (by showing the equipment or by certifying) that the idle-reduction technology works at all times, and that the extra 550 pounds isn't being used to carry anything else. (13) A vehicle carrying fluid milk products is treated as carrying a load that can't easily be taken apart or divided, which affects which special-permit exceptions apply to it. (b) Reasonable Access. No state may pass or enforce a law that denies covered trucks reasonable access between the Interstate System and nearby terminals and facilities for food, fuel, repairs, and rest. (c) Ocean Transport Container Defined. For this section, "ocean transport container" means the same thing as "freight container" in the International Standards Organization's Series 1, Freight Containers, 3rd Edition (reference IS0668-1979(E)), as that definition stood when this subsection became law. (d) Longer Combination Vehicles. (1) Prohibition. (A) A "longer combination vehicle" (defined in paragraph (4)) may keep operating only if that vehicle configuration was authorized by state law or regulation consistent with this section and was actually, regularly (including seasonally) in lawful operation on or before June 1, 1991 — or was authorized under a specific 1991 appropriations law provision. (B) All such operations stay subject to at least the state statutes, regulations, limits, and conditions — including route- and configuration-specific rules — that were in force on June 1, 1991. A state may make minor, temporary, emergency adjustments to routes and operating restrictions for safety or road-construction reasons, but only under regulations the Secretary issues under paragraph (5). (C) Wyoming may additionally allow vehicle configurations that weren't running on June 1, 1991 but were authorized by state law by November 3, 1992, as long as they meet the single-axle, tandem-axle, and bridge-formula limits in subsection (a) and don't exceed 117,000 pounds gross weight. (D) Ohio may additionally allow longer combination vehicles with three 28½-foot cargo units (not counting the truck tractor) that weren't running on June 1, 1991, but only on a specific one-mile stretch of Ohio State Route 7 south of exit 16 of the Ohio Turnpike. (E) Alaska may additionally allow longer combination vehicles that weren't running on June 1, 1991, as long as they were running before July 5, 1991. (F) Iowa may additionally allow longer combination vehicles that weren't running on June 1, 1991, on Interstate 29 (Sioux City to the South Dakota border) or Interstate 129 (Sioux City to the Nebraska border). (2) Additional state restrictions. (A) States remain free to further restrict or ban longer combination vehicles beyond what this subsection allows, as long as any such restriction or ban is consistent with 49 U.S.C. §§ 31111–31114. (B) A state that further restricts or bans these vehicles, or that makes a minor temporary emergency adjustment under the Secretary's regulations, must tell the Secretary within 30 days; the Secretary then publishes notice of that action in the Federal Register. (3) Publication of list. (A) Within 60 days of this subsection becoming law, each state had to send the Secretary, for publication in the Federal Register, a complete list of every longer-combination-vehicle operation running as of June 1, 1991 under state law, along with all limits and conditions governing such vehicles and copies of the underlying statutes and regulations. (B) Within 90 days, the Secretary had to publish an interim list of everything submitted, review it for accuracy, and take public comment on its accuracy. (C) A statute or regulation could not be included on a state's or the Secretary's list just because it theoretically could have authorized (by permit or otherwise) longer combination vehicles that weren't actually, regularly running on or before June 1, 1991. (D) Except as changed under paragraph (1)(C) for Wyoming, the Secretary had to publish a final list in the Federal Register within 180 days, fixing any inaccuracies found through the comment process. After that final list was published, longer combination vehicles can only operate on the Interstate System as the list allows. (E) The Secretary, on the Secretary's own initiative or at anyone's request (including a state's), can review the final list. If the Secretary finds reason to believe it contains a mistake, the Secretary must start a process to decide whether to correct it, and must correct the list if a mistake is confirmed. (4) "Longer combination vehicle" means a combination of a truck tractor and two or more trailers or semitrailers that operates on the Interstate System at a gross weight over 80,000 pounds. (5) Within 180 days of this subsection becoming law, the Secretary had to issue regulations setting the criteria states must follow when making minor adjustments under paragraph (1)(B). (e) Certain vehicles on Interstate 68 in Maryland. The single-axle, tandem-axle, and bridge-formula limits in subsection (a) do not apply, on Interstate 68 in Garrett and Allegany Counties, Maryland, to a specialized vehicle with a steering axle and a tridem axle that hauls coal, logs, or pulpwood — if that type of vehicle was already operating there on U.S. Route 40 or 48 for that purpose on August 1, 1991. (f) Certain vehicles on a Wisconsin highway. If a described 104-mile stretch of Wisconsin State Route 78 and U.S. Route 51 (between Interstate 94 near Portage and Wisconsin State Route 29 south of Wausau) becomes part of the Interstate System, this section's axle-weight, gross-weight, and bridge-formula limits do not apply on that stretch to any vehicle that could have legally operated there before this subsection became law. (g) Certain vehicles on a Pennsylvania highway. If the stretch of U.S. Route 220 between Bedford and Bald Eagle, Pennsylvania becomes part of the Interstate System, the same limits do not apply on that stretch to vehicles that could have legally operated there before this subsection became law. (h) Emergency waiver for a Maine route. (1) Working with the Secretary of Defense, the Secretary may waive or limit any weight limit under this section on Interstate 95 in Maine between Augusta and Bangor, so bulk jet fuel can be shipped to the Air National Guard Base at Bangor International Airport during a national emergency, to help respond to that emergency. (2) Any weight limit the Secretary sets this way overrides any conflicting state weight limit. (i) Special permits during national emergencies. (1) A state may issue special permits to overweight vehicles carrying loads that can be taken apart or divided, if: (A) the President has declared the emergency a major disaster under the Stafford Act; (B) the state issues the permits under its own law; and (C) the permits go only to vehicles delivering relief supplies. (2) Any such permit expires no later than 120 days after the disaster was declared. (j) Certain vehicles on other Wisconsin highways. If part of the U.S. Route 41 corridor described in a specific 1991 federal transportation law is designated part of the Interstate System, a vehicle that could legally operate there before that designation may keep operating there, regardless of subsection (a). (k) Certain vehicles on a Mississippi highway. If the stretch of U.S. Route 78 in Mississippi from mile marker 0 to mile marker 113 becomes part of the Interstate System, no limit under this section applies on that stretch to a vehicle that could legally have operated there before that designation. (l) Certain vehicles on Kentucky highways. (1)–(2) If either of two described highway segments — Interstate 69 (formerly the Wendell H. Ford Western Kentucky Parkway) from its Interstate 24 interchange to the Pennyrile Parkway interchange, or the Pennyrile Parkway itself, planned as future Interstate 69 — becomes part of the Interstate System, a vehicle that could legally operate there before that designation may keep operating, regardless of subsection (a). (3)(A) The same rule applies to five more described Kentucky parkway segments (the Natcher Parkway, the Purchase Parkway, the Western Kentucky Parkway, a Pennyrile Parkway spur, and the Nunn Cumberland Expressway), except that vehicles using this exception cannot exceed 120,000 pounds gross weight. (B) That 120,000-pound cap does not stop a state from issuing a normal nondivisible-load permit allowing a heavier vehicle. (m) Covered heavy-duty tow and recovery vehicles. This section's weight limits do not apply to a tow truck that (1) is moving a disabled vehicle from where it broke down to the closest suitable repair shop, and (2) itself weighs at least as much as the disabled vehicle it's towing. (n) Certain vehicles on Texas highways. If any segment of U.S. Route 59, 77, 281, 84, Texas State Highway 44, or another Texas road becomes designated as Interstate 69, a vehicle that could legally operate on that segment before the designation may keep operating there, regardless of any requirement of this section. (o) Certain logging vehicles in Wisconsin. (1) The Secretary must waive this section's weight limits for a "covered logging vehicle." (2) That means a vehicle that: (A) carries raw or unfinished forest products (logs, pulpwood, biomass, or wood chips); (B) weighs no more than 98,000 pounds; (C) has at least 6 axles; and (D) operates on Interstate 39 in Wisconsin between mile markers 175.8 and 189. (p) Certain vehicles on an Arkansas highway. If the stretch of U.S. Route 63 in Arkansas between the exits for Highways 14 and 75 becomes part of the Interstate System, this section's axle-weight, gross-weight, and bridge-formula limits — and the vehicle-width limit in 49 U.S.C. § 31113(a) — do not apply on that stretch to a vehicle that could legally have operated there before the designation. (q) Certain logging vehicles in Minnesota. Same rule as Wisconsin's in subsection (o), except the weight cap is 99,000 pounds and the covered stretch is Interstate 35 in Minnesota between mile markers 235.4 and 259.552. (r) Emergency vehicles. (1) A state cannot enforce, against an emergency vehicle, a weight limit (up to a maximum gross weight of 86,000 pounds) below: (A) 24,000 pounds on a single steering axle; (B) 33,500 pounds on a single drive axle; (C) 62,000 pounds on a tandem axle; or (D) 52,000 pounds on a tandem rear-drive steer axle. (2) "Emergency vehicle" means one built for emergency use, to carry personnel and equipment and to help fight fires or handle other hazardous situations. (s) Natural gas and electric battery vehicles. A vehicle powered mainly by natural gas or by electric battery may exceed this section's power-unit weight limit by up to 2,000 pounds, up to a maximum gross weight of 82,000 pounds. (t) Vehicles in Idaho. A vehicle that this section would otherwise limit or bar from an Idaho Interstate segment may operate there if it: (1) weighs 129,000 pounds or less; (2) otherwise (apart from gross weight) meets the single-axle, tandem-axle, and bridge-formula limits in subsection (a); and (3) is authorized to operate there under Idaho law. (u) Vehicles in North Dakota. The same three-part rule as Idaho's applies in North Dakota: 129,000-pound cap, compliance with the other axle and bridge-formula limits, and authorization under North Dakota law. (v) Certain vehicles on North Carolina highways. If any segment of U.S. Route 17, 29, 52, 64, 70, 74, 117, 220, 264, or 421 in North Carolina becomes designated part of the Interstate System, a vehicle that could legally operate on that segment before the designation may keep operating there, regardless of subsection (a). (w) Certain vehicles on an Oklahoma highway. If the highway segment described in a specific paragraph of a 1991 federal transportation law becomes designated part of the Interstate System, a vehicle that could legally operate there before the designation may keep operating there, regardless of any requirement of this section. (x) Certain agricultural vehicles in Mississippi. (1) Mississippi may issue special permits letting a "covered agricultural vehicle" operate on its Interstate System up to: (A) 88,000 pounds gross weight; and (B) 110 percent of the maximum axle or axle-group weight allowed under subsection (a)(2), including enforcement tolerances. (2) A "covered agricultural vehicle" is one hauling unprocessed food, feed, or fiber crops, or raw or unfinished forest products such as logs, pulpwood, biomass, or wood chips. (y) Certain vehicles in West Virginia. (1) West Virginia may issue special permits letting a vehicle hauling "materials and equipment" operate on its Interstate System up to 110 percent of the maximum axle or axle-group weight allowed under subsection (a)(2), including enforcement tolerances — as long as the vehicle still meets subsection (a)'s other gross-weight requirements. (2) "Materials and equipment" means materials and equipment used on a highway project that qualifies for funding under this title (title 23).