Motor carrier classes by state
Minnesota is the rare state that moves its weight limits in both directions. A gravel hauler here gets ten percent more capacity in January than the statute otherwise allows, then loses more than a third of a consecutive axle group on gravel in March — and the two changes happen at the same instant, in whichever of six zones the pit sits in.
The parts of dump and aggregate hauling that behave the same in every state — the short-radius duty cycle, the off-road exposure at the pit and at the placement site, the way a body-up strike or an overturn dominates the loss history — belong to the class rather than to Minnesota, and they are set out on the dump trucking insurance page instead of being repeated here.
What Minnesota adds is a weight calendar that runs in two directions across a single year. Minnesota Statutes section 169.826, subdivision 1 raises the limits in sections 169.823 to 169.829 by ten percent between dates the commissioner sets for each zone from a freezing index model each winter. Minnesota Statutes section 169.87, subdivision 2 then cuts a single axle to five tons on an unpaved road and ten tons on a paved one between dates the commissioner of transportation sets each year. The same office sets both, for the same zones, and the published table gives the end of the winter increase and the start of the spring restriction as one date rather than two.
The zones matter as much as the dates. MnDOT operates six seasonal load limit zones — North, North-Central, Central, Metro, South and Southeast — and publishes a start and end date for each. For the 2025 to 2026 season the winter increase in the North zone began December 12, 2025 and ended, with spring restrictions starting, on March 20, 2026; restrictions there ended May 15, 2026. In the Metro, South and Southeast zones the same transition fell on March 3, 2026, with restrictions ending April 20, 2026. Every one of those dates begins at 12:01 a.m. and carries at least three days of advance notice, per the MnDOT seasonal load limit schedule.
Every figure below is attributed to the statute, rule or agency publication that sets it, with the date or season that version applies to. Minnesota moves these numbers annually and by zone, so a haul rate or an equipment schedule built on last season’s dates is already describing a different state than the one the truck is driving through.
Hauling out of a pit that sits in one zone and delivering into another? Send the zone list with the truck list — the calendar an account runs on is a rating fact, not a footnote.
Most states treat spring thaw as the only weight event of the year. Minnesota treats the frozen months as an event too, and in the opposite direction. Under Minnesota Statutes section 169.826, subdivision 1, as published in the 2025 statutes, the limits in sections 169.823 to 169.829 are increased by ten percent between the dates set by the commissioner for each zone established by the commissioner based on a freezing index model each winter. The increase is automatic within the declared window rather than something an operator applies for, although subdivision 3 of the same section requires a permit for a vehicle exceeding 80,000 pounds gross on Interstate routes during an increase.
The spring side is Minnesota Statutes section 169.87, and its subdivision 2 opens with the same construction — between the dates set by the commissioner of transportation each year. One statute raises, the other lowers, and both are triggered by a date the same agency publishes for the same six zones.
The published schedule shows those two events sharing a boundary rather than sitting apart. In the MnDOT table of start and end dates the column that ends the winter load increase is the same column that starts the spring load restriction: March 20, 2026 in the North zone, March 18 in North-Central, March 6 in Central, and March 3 in the Metro, South and Southeast zones for the 2026 season. A truck that was legally ten percent heavy at 11:59 p.m. is running a restricted road six hours later.
For a dump operator that transition is the sharpest revenue edge in the year, and it is sharper than it looks on paper, because the capacity swing between the two states is far larger than the ten percent that gets quoted. The winter increase and the spring group reduction are measured from the same baseline in opposite directions, and the operator crosses the whole distance in one night.
The absolute number is in Minnesota Statutes section 169.87, subdivision 2(a), 2025 statutes: unless restricted under subdivision 1, between the dates set by the commissioner of transportation each year, the weight on any single axle shall not exceed five tons on an unpaved street or highway, or ten tons on a paved street or highway. Aggregate hauling is disproportionately exposed to the first of those two numbers, because the loaded end of a gravel run is frequently the unpaved end.
Subdivision 2(b) is the provision that is most often missed, and it is the one that does the damage. The gross weight on consecutive axles on an unpaved street or highway shall not exceed the gross weight allowed in sections 169.823 to 169.829 multiplied by a factor of five divided by nine, and that reduction does not apply to the gross vehicle weight. Five divided by nine is a reduction of more than forty-four percent applied to the axle group allowance, and it stacks on top of the five-ton single axle cap rather than replacing it. A tri-axle or a quad that is legal at the plant scale can be over on the group calculation the moment it leaves pavement.
The signed layer sits on top of that. MnDOT publishes seasonal load limit maps showing the six zones and the routes that carry load restrictions of five or seven tons during spring load restrictions, and states that Minnesota, US and Interstate highways not shown in the legend are rated at 10 tons. So a Minnesota route in March is one of three things — unrestricted at its ten-ton rating, posted at seven, or posted at five — and only the map and the signs settle which.
Section 169.87 subdivision 1 makes the signs constitutive rather than informational. A local restriction is not effective unless and until the signs are erected and maintained at each end of the affected portion, and a commissioner-imposed restriction is effective when signs giving notice are erected. That is a useful thing for a driver to understand and a dangerous thing for a dispatcher to rely on, because the sign is the last link in a chain that started with a published date three days earlier.
Minnesota does not begin spring restrictions on a calendar date or on an inspector’s judgment. It begins them on an arithmetic threshold. MnDOT’s published thaw definitions state the load restriction criteria as a cumulative thawing index greater than 25 DegFDays together with a weather forecast that predicts further increases in the thawing index. The cumulative thawing index is the summation of the daily thawing indices, and the reference temperature the daily index is measured against is not fixed — MnDOT states that it varies from 29 degrees F on February 1 to 24 degrees F on March 15.
That ramp is the part worth understanding, because it means the instrument gets more sensitive as the season progresses. Late in the window a smaller temperature excess counts as thawing than would have counted in early February. Two springs with similar-looking weather can produce start dates two weeks apart, and an operator who plans on an average start date rather than on the announced one is planning on a number the agency never uses.
The announcement mechanics are equally specific. MnDOT states that all starting and ending dates begin at 12:01 a.m. and are preceded by at least a three-day advance notice, published per zone. Three days is enough to finish a load and reposition equipment. It is not enough to renegotiate a placement schedule with a general contractor, which is exactly why the seasonal risk on a Minnesota aggregate account tends to land on the contract rather than on the truck.
The two ends of the season behave differently in practice as well. The start is forecast-driven and therefore arrives with the minimum notice the agency commits to. The end depends on how far the thaw has worked down through the base, which is why the restriction end dates in the 2026 table ran from April 20 in the southern zones to May 15 in the North — a spread of nearly four weeks across a single state.
We place Minnesota aggregate and dump accounts across single-axle, tandem, tri-axle and transfer configurations, including operators running pits in more than one seasonal load limit zone.
It is common to describe every state’s non-Interstate weight rule as the federal bridge formula with local trimming. That description does not fit Minnesota. Minnesota Statutes section 169.824, subdivision 1, publishes a schedule of maximum gross weights indexed to the distance in feet between the centers of the first and last axles of a group, with separate columns for two-axle through eight-axle groups, and with parenthetical entries denoting weights allowed only on paved streets and highways. It is a table in the statute, not a formula referenced by the statute.
Subdivision 2 sets the ceiling above that table: the gross vehicle weight of all axles of a vehicle or combination must not exceed 80,000 pounds on all streets and highways, with a narrow exception permitting 88,000 pounds for a vehicle with six or more axles hauling livestock on non-Interstate trunk highways under permit. Aggregate is not inside that exception, which means an eighty-thousand-pound ceiling is the practical planning number for a Minnesota dump combination in every season including the winter increase window on non-Interstate routes.
The federal grandfather question resolves the same way. Title 23 of the United States Code, section 127 preserves higher state limits in effect on July 1, 1956 for the Interstate System, and the only Minnesota-specific relief written into that section is subsection (q), which lets the Secretary waive the limits for a vehicle transporting raw forest materials — logs, pulpwood, biomass or wood chips — at not more than 99,000 pounds with at least six axles, on a segment of Interstate Route 35 in the State of Minnesota from mile marker 235.4 to mile marker 259.552.
That is a carve-out measured in tenths of a mile and written for a different commodity. Sand, rock, crushed concrete and fill do not reach it, and the twenty-four-mile segment it describes is not a haul road for anyone moving aggregate. Minnesota is, for practical purposes, an eighty-thousand-pound state with a state-authored axle table underneath it and a seasonal overlay on top.
Minnesota does not run one overweight permit regime. It runs three, sequenced against the same six zones the load restrictions use, and the sequence decides what an operator can even apply for on a given week rather than what he is likely to be granted.
MnDOT publishes middle-range and full-summer overweight maximum permit weights as separate tiers, and describes the sequence plainly: middle-range overweight permits become available within a zone when spring load restrictions are lifted there, and full-summer overweight permits become available two to three weeks after that. For the 2026 season the full-summer tier in the southern zones opened in early May, after restrictions ended April 20; the northern zones followed at the end of May, after restrictions ended May 13 and May 15.
The consequence for a dump and aggregate operation is oblique but real. Aggregate itself moves under the ordinary weight rules rather than under an overweight permit, so the tiers do not change what a gravel load may weigh. What they do change is the operator’s ability to move his own iron — a loader, a screening plant, an excavator on a lowboy — during the weeks on either side of the restriction window. An operator who intends to reposition equipment between pits in early May in the North zone is planning that move inside a permit tier that has not opened yet.
There is a scheduling discipline in that which underwriters notice. An account that knows which zone each of its pits falls in, which permit tier is open in that zone this week, and when its own equipment moves are booked is an account that is managing the calendar rather than reacting to it. The same discipline usually shows up in the driver files and in the pre-trip records, and it is one of the more reliable soft signals on a seasonal class.
The physical exposures on a Minnesota dump truck are the class exposures, and they do not change at the state line. What changes is the shape of the year the exposures are spread across, and that shape drives several of the questions asked at submission:
None of those questions is about the truck. All of them are about the calendar the truck runs on, and that is the distinguishing feature of the Minnesota account. An operator who can answer them in zone terms rather than in statewide terms is describing his own business the way the state describes it, which shortens the conversation considerably.
The insurance consequence that recurs most often is on the property and time-element side rather than the auto side. A compressed operating season concentrates revenue, so a mechanical failure or a fire in a shop during the open weeks costs a disproportionate share of the year. That is physical damage and equipment territory sitting next to a business income question, and it is worth raising before the season rather than after it.
The liability side has its own seasonal signature. The first weeks after a restriction lifts are the weeks when the road network is busiest with deferred work, when new hires are being put into seats, and when placement sites are softest underfoot. Overturn and body-contact losses cluster there, which is a trucking auto liability conversation informed by a MnDOT date table. Where the loss happens at the pit or on a placement site rather than on a road, it is a general liability question instead, and the two are easier to sort out before the season than during it.
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 Minnesota 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 Minnesota 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.
Five tons. Minnesota Statutes section 169.87, subdivision 2(a), as published in the 2025 statutes, provides that between the dates set by the commissioner of transportation each year the weight on any single axle shall not exceed five tons on an unpaved street or highway, or ten tons on a paved street or highway. The unpaved figure is the one that governs most loaded aggregate movements, because the loaded end of a gravel run is frequently off pavement.
It reduces the axle group allowance, not the gross. Subdivision 2(b) provides that the gross weight on consecutive axles on an unpaved street or highway shall not exceed the gross weight allowed in sections 169.823 to 169.829 multiplied by a factor of five divided by nine, and states that the reduction does not apply to the gross vehicle weight. Five divided by nine is a cut of more than forty-four percent, applied on top of the five-ton single axle cap rather than instead of it.
Six — North, North-Central, Central, Metro, South and Southeast. MnDOT publishes a start and end date per zone for both the winter load increase and the spring load restriction. For the 2026 season, restrictions started March 20 in the North zone and March 3 in the Metro, South and Southeast zones, and ended May 15 and April 20 respectively. All dates begin at 12:01 a.m. and carry at least three days of advance notice.
By a computed index rather than a fixed date. MnDOT’s published criteria call for a cumulative thawing index greater than 25 DegFDays together with a forecast predicting further increases in the index. The cumulative index is the summation of daily thawing indices, measured against a reference temperature that MnDOT states varies from 29 degrees F on February 1 to 24 degrees F on March 15, so the instrument grows more sensitive as spring advances.
Yes, within declared windows. Minnesota Statutes section 169.826, subdivision 1 increases the limitations in sections 169.823 to 169.829 by ten percent between dates set by the commissioner for each zone based on a freezing index model each winter. Subdivision 3 of the same section requires a permit for vehicles exceeding 80,000 pounds gross on Interstate routes during an increase. The winter increase for the 2026 season began between December 12 and December 29, 2025 depending on zone.
No. Minnesota Statutes section 169.824, subdivision 1 publishes its own schedule of maximum gross weights indexed to the spacing between the first and last axles of a group, with separate columns for two-axle through eight-axle groups and parenthetical entries for weights allowed only on paved roads. Subdivision 2 caps gross vehicle weight at 80,000 pounds on all streets and highways, with a narrow permitted exception at 88,000 pounds for six-or-more-axle livestock hauling on non-Interstate trunk highways.
Not one that reaches aggregate. Title 23 of the United States Code, section 127 preserves state limits in effect on July 1, 1956 for the Interstate System, and the only Minnesota-specific provision in that section is subsection (q), a waiver for vehicles carrying raw forest materials at not more than 99,000 pounds with at least six axles on Interstate Route 35 from mile marker 235.4 to mile marker 259.552. Sand, rock and fill fall outside both the commodity and the segment.
They govern equipment moves rather than loads of aggregate. MnDOT sequences permit capability against the same six zones: middle-range overweight permits open within a zone when spring restrictions are lifted there, and full-summer permits open two to three weeks later. An operator planning to move a loader or a screening plant on a lowboy in the weeks around the restriction window should confirm which tier is open in that zone before booking the move.
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.
