Motor carrier classes by state
Montana lets a reducible load reach 131,060 pounds off the Interstate, and it does not sell that capacity as a permit. It sells it at the registration counter, on a fee schedule keyed to the gross weight the owner declares. That one design decision reorganizes almost everything else about running aggregate here.
The exposures that make dump and aggregate work hard to underwrite are common to the class wherever it operates — the short-haul frequency profile, the job-site and pit work that sits at the edge of a highway auto form, the hoist and body damage that rarely matches what a physical damage schedule assumed. Those belong to the class, and they are covered on the dump trucking insurance page rather than restated here.
What Montana contributes is a weight regime built on a different premise from most states. Elsewhere the legal ceiling is a low number and additional capacity is rented, load by load or season by season, through a permit office. Montana sets a high statutory ceiling off the Interstate system, makes it reachable through vehicle configuration, and then collects for it annually as a licensing fee based on the maximum gross loaded weight the licensee writes on the application.
That has a direct commercial consequence for an aggregate hauler. The decision about how much a truck can carry in Montana is made once a year, in an office, by the owner — not repeatedly at a permit counter or a scale. It is a capital and registration decision rather than an operational one, and the paperwork that proves it is a registration document rather than a permit book. Anyone assembling a Montana dump fleet is choosing an axle configuration and a declared weight together, and living with both for the license year.
One caution belongs at the top rather than buried below. Montana’s spring load restrictions are handled very differently from its weight regime, and this page does not publish a current tonnage table for them, because the state does not maintain one in any current document. What the law does say about how those restrictions take effect is set out in the last section, and it is more useful than a table would be. Everything else here is cited to the statute, rule or department publication that sets it, with the date that version carries.
Registering a Montana fleet for more than 80,000 pounds? Send the declared gross weights alongside the axle configurations — in Montana those two numbers have to be read together.
61-10-201 MCA, last amended by Ch. 327, L. 2001, is the provision that shapes the Montana aggregate business more than any other. It requires an annual fee for each truck, truck tractor and bus, and it states the basis explicitly: for vehicles above one ton the fee rests on “the maximum gross loaded weight and the maximum gross weight of any towed unit of each truck and truck tractor as set by the licensee in the licensee’s application.”
The licensee sets the number. That is the whole mechanism. The statute then runs a schedule in 2,000-pound bands — $21.00 up to 16,000 pounds, rising through the bands to $750.00 for 78,001 through 80,000 pounds — and treats 80,000 as a hinge rather than a ceiling. Above it, the fee becomes $750.00 plus an additional $46.00 for each ton or fraction of a ton in excess of 80,000 pounds, plus a further $100.00 simply to exceed the 80,000-pound federal gross weight limit.
Read the structure rather than the individual amounts. Montana prices the first 80,000 pounds in graduated steps and then prices everything above it linearly, at a flat rate per ton, with a single flat surcharge for crossing the federal line at all. There is no per-trip charge, no mileage component and no seasonal renewal in that calculation. An operator who configures a truck to carry more and declares it pays once and hauls all year.
The insurance consequence is that Montana produces an unusually good primary document. A declared gross weight on a registration is an owner’s own statement of the maximum the unit is built and licensed to carry, and it can be reconciled directly against an equipment schedule, against the axle configuration, and against what the operator says the trucks actually haul. Where those three disagree, the disagreement is worth resolving before binding. A unit licensed at 80,000 pounds and routinely loaded past it is not just a registration problem — it is an exposure the physical damage and auto liability pricing never saw.
The figure every Montana aggregate operator quotes is 131,060 pounds, and the state’s own publication puts it plainly. The Montana Commercial Vehicle Size and Weight and Safety Trucker’s Handbook, Ninth Edition, April 2026, states directly on its gross vehicle weight chart that “maximum gross weight for reducible loads is 131,060 pounds,” citing 61-10-107 MCA. Reducible — divisible — is the word that matters: this is the ceiling for a load that could be broken down, which is exactly what sand, gravel, stone and fill are.
The handbook’s citation is slightly generous to the statute, and the difference is worth knowing. 61-10-107 MCA, as carried in the Montana Code Annotated 2025, does not itself state 131,060. It sets the axle limits, provides the weight formula, and then delegates: “The maximum gross weight allowed on a vehicle may not exceed the weight limits adopted by the department. The department shall adopt rules for weight limits based upon the most recent version of 23 CFR, part 658, appendix c.” The number lives in the department rule made under that delegation — Mont. Admin. r. 18.8.431, most recently amended effective June 25, 2022, whose subsection (1) reads that the maximum allowable gross weight for vehicle combinations hauling divisible loads is 131,060 pounds.
The route to that ceiling is configuration, not paperwork. Montana caps a single axle at 20,000 pounds and any two consecutive axles more than 40 inches and less than 96 inches apart at 34,000 pounds, and allows gross weight to rise with axle count and wheelbase under the statutory formula. The handbook’s published chart reflects that: the high figures sit in the columns for combinations carrying many axles over a long wheelbase, and 131,060 is where the chart stops. A conventional tandem or tri-axle dump does not approach it. Reaching it means running a configuration — typically a truck and pull trailer or a multi-axle transfer arrangement — bought and built for the purpose.
The last clause of 61-10-107 is the one that catches out-of-state fleets. Subsection (3) states that the section does not apply to highways forming part of the national system of interstate and defense highways where applying it would prevent Montana from receiving federal highway funds. In practical terms, the 131,060-pound world is a non-Interstate world. An aggregate combination built for Montana secondary and US routes drops back to the federal 80,000-pound regime the moment it enters the Interstate, which makes routing a weight decision and not merely a mileage one.
Heavier axles need more rubber under them, and Montana writes that requirement into the same statute rather than leaving it to equipment practice. Subsection (2) (a) of 61-10-107 MCA provides that notwithstanding a vehicle’s conformance with the weight limits, and except for the steering axle, all axles weighing over 11,000 pounds must have at least four tires or have wide-base tires.
The alternative comes with its own arithmetic. Where an axle other than a steering axle runs wide-base tires, the statute limits the maximum load on that axle to 500 pounds for each inch of tire width. Subsection (2) (c) defines wide-base tires as tires 14 or more inches in nominal width, and directs that the weight limit be computed from the number of inches shown on the tire marking, converting from metric sizing where the marking is metric. Subsection (2) (b) excepts passenger buses from the requirement entirely.
For a dump operator this is the provision that quietly constrains equipment specification. An 11,000-pound threshold is low enough that essentially every loaded axle on a working aggregate truck sits above it, so the four-tire-or-wide-base requirement applies across the fleet rather than to a handful of heavy units. And because the wide-base allowance is computed per inch of marked tire width rather than per axle, an operator who converts to wide-base singles is accepting a per-axle limit that scales with the tire he actually bought — a specification decision with a legal weight consequence attached.
It also shows up on the schedule. Wide-base conversions change tire cost, spare inventory and roadside exposure, and they change the replacement arithmetic after a blowout. None of that alters an insurance requirement, but it does change what a total loss and a partial loss on a Montana unit look like, and it belongs in the same conversation as the declared gross weight rather than in a separate one.
We place Montana aggregate and dump accounts, including multi-axle configurations licensed above 80,000 pounds and operators running seasonal winter weight permits.
Montana operates a seasonal permit that runs the opposite direction from the one most operators expect, and it is genuinely unusual in reaching divisible loads. The Trucker’s Handbook, Ninth Edition, April 2026, sets out the winter weight term permit in four lines, and each one carries weight for an aggregate hauler:
The reasoning is the same physics that produces spring restrictions, applied in the other direction. Deeply frozen subgrade carries load better than thawing subgrade, so the state that will restrict weight in March is willing to add it in January. What distinguishes Montana is that it extends the benefit to reducible loads generally rather than reserving it for a named commodity list, which is not how the neighboring states handle their winter programs.
The two limiting conditions are what a hauler should plan against rather than the 10 percent itself. The permit is expressly not valid on posted bridges or roads, so it never overrides a local posting — and Montana postings are made route by route, as described in the last section. And it can be suspended for early thawing, which means a haul plan built on winter tonnage is built on something the department can withdraw when the weather turns. A seasonal contract priced on 10 percent extra payload should carry the assumption that the 10 percent may not survive the whole window.
For operators who run permitted work more broadly, Montana also issues term overweight permits for non-reducible loads in bands from 5,000 to 40,000 pounds of excess, purchasable annually, semi-annually or quarterly, with a $10.00 administrative fee on purchases of less than a year and no grace period. That is a different program for different freight, and it sits alongside the oversized and overweight side of a mixed fleet rather than the aggregate side.
Montana carries three border arrangements that produce weights above even the 131,060-pound ceiling, and an aggregate operator working the Hi-Line should know what they are and — more usefully — what they are not.
The statutory hook sits in 61-10-107 (1) (b) MCA, which removes the formula for a vehicle traveling on US Highway 93 from the Canadian border to 10 miles south, or on Montana Highway 16 from the Canadian border to 20 miles south, and substitutes the specific maximum allowable gross weight in department rule. Mont. Admin. r. 18.8.431 supplies that figure: 137,800 pounds, both for combinations operating under 23 CFR part 658 appendix C as of its April 1, 2015 edition and for those operating under 61-10-107 (1) (b). The department’s Canadian Weight Information in MT guidance adds the third arrangement, listing “Canadian weight loads between Sweet Grass/Alberta and Shelby” among the movements for which overweight permits may be issued, alongside the Eureka corridor on US 93 and the Plentywood corridor on Montana 16.
The important qualification is in the configurations those weights attach to. The same guidance defines A trains, B trains and C trains — multi-trailer combinations joined by tongue hitch, fifth wheel or converter dolly — and publishes the corridor weights against them: a five-axle tractor-semitrailer at a maximum gross of 87,100 pounds with a 12,100-pound steering axle and 37,500 pounds on each of the drive tandem and trailer groups, and a six-axle tractor-semitrailer at 102,500 pounds depending on tridem spacing. The 137,800-pound figure belongs to eight-axle B-train territory, not to a dump truck.
So the honest read for an aggregate hauler is that the Canadian corridors are real, geographically tiny, permit-based, and built for a kind of equipment most Montana dump operators do not own. They matter to the account that runs cross-border bulk work with train combinations. They are a footnote to the account hauling pit run to a county job. Any operator who does cross the line should be checking authority, filings and cargo terms alongside the weight tables, because the weight is the least complicated part of a cross-border move.
One related figure from the same guidance is worth carrying back into the registration discussion above: vehicles operating on non-divisible load overweight permits must be licensed for the maximum gross weight, up to 132,000 pounds, determined by the bridge formula measured from first to last axle. Even on the permit side, Montana keeps sending the operator back to the declared licensed weight.
Every state on Montana’s borders publishes a seasonal restriction framework with tonnages, zones or a calendar attached. Montana does not, and the absence is deliberate enough to be the most useful thing to understand about it.
61-10-128 MCA, last amended by Ch. 90, L. 2019, states no tonnage and no tire-width figure anywhere in its text. It authorizes the department of transportation by order, or a local road authority by ordinance or resolution, to prohibit operation or impose weight and speed restrictions on a highway under its jurisdiction whenever the highway would be seriously damaged by deterioration, rain, snow or other climatic conditions. Then it sets the condition that governs everything: the department or authority “shall erect signs designating the department’s order or the authority’s ordinance or resolution at each end of that portion of the highway affected, and the order, ordinance, or resolution is not effective until the signs are erected.”
That sentence is the whole system. A Montana restriction is not a season, a zone or a published table — it is a specific order on a specific stretch of road, and it has no legal effect at all until the signs are physically up. The April 2026 Trucker’s Handbook is consistent with this: its seasonal weight restrictions section describes the mechanism, notes that signs indicating lower weights are erected at the beginning of a posted road, and directs operators to the department’s load and speed restrictions site rather than reproducing any numbers.
The department does publish restriction levels, and they should be read with their date attached. MDT’s Load and Speed Limit Policy, which the department’s own page stamps as revised 02-07-2001, describes a graduated approach — reduced speed limits alone where the surface still carries legal loads, then load restrictions of 8 tons single axle and 16 tons tandem axle equivalent to 400 pounds per inch of tire width, then a more restrictive 7 tons single axle and 14 tons tandem axle equivalent to 350 pounds per inch. Those are the levels that policy contemplates, on a document carrying a 2001 revision date and not restated in the 2026 handbook. They are useful for understanding the order of magnitude a Montana posting can impose. They are not a schedule to dispatch against.
Two statutory exemptions sit alongside the restriction power and are narrow enough to be worth naming precisely. Under 61-10-128 (3), neither the department nor a local authority may restrict the weight of a vehicle loaded with perishable seed potatoes or with fertilizer, provided the vehicle operates within its legal licensed gross vehicle weight, the driver carries a federal-state inspection certificate or bill of lading for the load, and the vehicle takes the most direct route from loading or unloading to the nearest unrestricted road. Subsection (4) exempts hay grinders and their towing units. Aggregate appears in neither.
What that means operationally is that route knowledge substitutes for a published table, and that is a dispatch and driver control rather than a paperwork one. It also means the underwriting questions on a Montana aggregate account look different from those on a state with a seasonal calendar:
The state minimum is a licensing threshold. The program an operator actually needs is built from these lines:
We write dump and aggregate hauling as a named class rather than as an exception to general trucking, and we read each account against the weight and permit regime of the state it operates in. For a Montana operator that means starting from what the trucks are actually licensed and configured to carry, sizing physical damage to bodies and hoists rather than to a chassis value, and treating pit, stockpile and job-site work as its own exposure rather than an extension of the highway auto form.
If the operation also runs freight under separate authority, the Montana trucking insurance page covers the state’s broader motor carrier picture, and the dump trucking insurance page covers the class mechanics that apply wherever the operator runs.
For reducible — divisible — loads on non-Interstate highways the ceiling is 131,060 pounds. The MDT Trucker’s Handbook, Ninth Edition, April 2026, states it on its gross vehicle weight chart, and Mont. Admin. r. 18.8.431 (1), amended effective June 25, 2022, carries the same figure as the maximum allowable gross for combinations hauling divisible loads. Reaching it requires a long, many-axled configuration; a conventional tandem or tri-axle dump does not come close.
Not in the ordinary case. Montana handles additional capacity through licensing rather than permitting. Under 61-10-201 MCA, amended by Ch. 327, L. 2001, weight fees are assessed annually on the maximum gross loaded weight the licensee sets in the application. Above 80,000 pounds the fee is $750.00 plus $46.00 for each ton or fraction of a ton in excess, plus a further $100.00 to exceed the 80,000-pound federal gross weight limit.
No. Subsection (3) of 61-10-107 MCA provides that the section does not apply to highways in the national system of interstate and defense highways where applying it would prevent Montana from receiving federal highway funds. In practice the higher Montana ceiling is a non-Interstate ceiling, and a combination built for it reverts to the federal 80,000-pound regime on the Interstate. Route selection in Montana is therefore a weight decision as much as a distance one.
It is a seasonal permit that adds weight rather than removing it. Per the MDT Trucker’s Handbook, Ninth Edition, April 2026, it allows 10 percent excess weight on non-Interstate highways from December 1 through March 7, priced at $50.00 for 30 days or $150.00 for the duration. It cannot be combined with other overweight permits, is not valid on posted bridges or roads, and can be suspended due to early thawing of Montana roads.
Montana does not publish a current statewide table, and 61-10-128 MCA states no tonnage figure at all. The department’s Load and Speed Limit Policy, which MDT stamps as revised 02-07-2001, describes restrictions of 8 tons single and 16 tons tandem, equivalent to 400 pounds per inch of tire width, and a more restrictive 7 tons single and 14 tons tandem at 350 pounds per inch. Those levels carry a 2001 revision date and are not restated in the 2026 handbook.
Only when the signs go up. 61-10-128 MCA, amended by Ch. 90, L. 2019, requires the department or local authority to erect signs at each end of the affected portion of highway, and states that the order, ordinance or resolution “is not effective until the signs are erected.” Montana restrictions are made route by route rather than by zone or calendar, so the sign at the end of the segment is the operative notice for a driver.
Under 61-10-107 (2) (a) MCA, and except for the steering axle, every axle weighing over 11,000 pounds must have at least four tires or wide-base tires. Where wide-base tires are used on an axle other than a steering axle, the load is limited to 500 pounds for each inch of tire width, with wide-base defined in subsection (2) (c) as 14 or more inches nominal width. Passenger buses are excepted. The threshold is low enough to reach every loaded axle on a working dump truck.
Rarely. 61-10-107 (1) (b) MCA covers US Highway 93 within 10 miles of the border and Montana Highway 16 within 20 miles, and Mont. Admin. r. 18.8.431 sets 137,800 pounds for qualifying combinations; MDT guidance adds the Sweet Grass to Shelby arrangement. Those weights attach to A, B and C train configurations — the guidance shows a five-axle tractor-semitrailer at 87,100 pounds — so they matter to multi-trailer cross-border operators, not to a typical dump fleet.
Every figure on this page was read at the source below on August 11, 2026, with the effective date of the version read. Treat each as current as of that date rather than as permanent.
Send the declared or registered weights alongside the axle configurations, and tell us where the material moves from. We will size the program against the work the trucks actually do rather than against a statutory floor.
