By Evan Reid, Founder of Haul Handbook · Updated Sep 28, 2026
MDT Motor Carrier Services issues oversize and overweight permits through the MT eTRIPS system, by phone at (406) 444-7262, or at weigh stations. Montana's legal limits are 8 feet 6 inches wide and 14 feet high, a 53-foot semitrailer with no overall length cap, and no flat gross weight cap: gross weight follows the bridge formula up to 131,060 pounds for reducible loads. A trip oversize permit costs $10 and an annual oversize term permit $75. Loads over 18 feet wide, 17 feet high or 150 feet long are superloads that need district approval.
Who issues what in Montana
The permit pages
Montana-specific requirements
Montana issues no freight operating authority. The PSC certificates only garbage haulers, regular-route carriers and ride-hail networks, while MDT assigns intrastate carriers a USDOT number marked with an MT suffix. MDT's Motor Carrier Services Division is the single office for IRP, IFTA licensing, UCR and oversize permits, and Montana layers its own gross vehicle weight fees on top of registration.
USDOT number with an MT suffix
MDT assigns intrastate carriers a USDOT number that must be marked on each truck immediately followed by MT, together with the carrier's name, and the MCS-150 must be updated every 24 months.
No flat 80,000-pound cap
Montana limits gross weight by axle limits (20,000 pounds single, 34,000 tandem) and the bridge formula rather than a single figure; MDT's gross vehicle weight chart runs to 131,060 pounds for reducible loads.
14-foot legal height
Montana allows 14 feet of height without a permit, and hay or straw moved up to 25 miles incidental to farming may reach 15 feet 6 inches.
GVW fees on top of registration
Every Montana-registered truck, truck tractor and bus pays a separate gross vehicle weight fee set by its declared maximum gross loaded weight, from $7 for a half-ton truck to $750 a year at 78,001 to 80,000 pounds and beyond.
Wintertime weight permit
From December 1 through March 7 a $50 (30-day) or $150 (full duration) permit allows 10 percent extra weight on non-interstate highways; it can be suspended early when roads thaw and is not valid on posted bridges or roads.
Rocky Mountain doubles and triples by permit
Term permits allow Rocky Mountain doubles up to 81 feet of combined trailer length (88 feet for hay), 100-foot doubles on the interstate, and triples up to 110 feet on the interstate only.
Intrastate freight liability floor is the state auto minimum
ARM 18.8.1502(2)(b) applies the federal 49 CFR 387 minimums only to interstate for-hire and hazardous materials carriers, and names the Mont. Code Ann. 61-6-103 motor vehicle liability policy as the minimum for for-hire carriers hauling nonhazardous material intrastate.
Chains carried October through April
From October 1 through April 30, motor trucks of 26,001 pounds or more towing a trailer must carry approved traction devices wherever chains may be required, unless four-wheel drive.
Trucks of 26,000 pounds or more stop at scales
All vehicles or combinations with a gross vehicle weight of 26,000 pounds or more must stop at open weigh stations (Mont. Code Ann. 61-10-141). PrePass and Drivewyze bypass is available, but overweight loads, loads over 10 feet wide or over 15 feet 6 inches high, and oversize loads without a permit must still enter.
Holiday weekends close for wide loads
Holiday closures extend to adjoining weekends, and Thanksgiving closes Thursday through Sunday for loads over the holiday limits (over 18 feet wide on the interstate; over 12 feet 6 inches wide, 150 feet long or 15 feet 6 inches high elsewhere).
The Montana permit system
- Apply or log in (MT eTRIPS (online self-issue permitting, live since December 2025))
- etrips.mtmdt.us
More Montana rules that catch carriers out
- State carrier number: summary
- Intrastate carriers use a USDOT number marked with the suffix MT (ARM 18.8.1502(2)(d)); PSC Class A and D carriers also hold a PSC number. See the state intrastate authority page.
- UCR participation: summary
- Montana participates in UCR. MDT Motor Carrier Services collects it for carriers operating commercial motor vehicles over 10,000 pounds in interstate or international commerce, and IRP credentials are not issued until UCR is paid. Carriers are pointed to ucr.gov to register online, or may send a UCR application with a check payable to MDT.
- GVW fees: summary
- Every Montana-registered truck, truck tractor and bus pays a gross vehicle weight fee on top of its registration, based on its declared maximum legal gross loaded weight (Mont. Code Ann. 61-10-201). The annual 100 percent schedule runs from $7 (half-ton rated capacity) through $750 at 78,001 to 80,000 pounds and $2,184 at 136,001 to 138,000 pounds, and may be bought for a full year, one month or several months (vehicles registered under 24,001 pounds only by the half year or year), plus a $5 re-registration fee on each GVW permit. Qualifying farm vehicles pay 35 percent fees.
- ELD intrastate adoption: regulation
- ARM 18.8.1502 (adopting 49 CFR parts 390 through 399, Part 395 included, as updated through March 10, 2026, amended effective 5/9/2026)
- ELD intrastate adoption: summary
- MDT adopts 49 CFR Part 395 by reference for the motor carriers it regulates under Mont. Code Ann. 61-10-154, as updated through March 10, 2026, so a Montana intrastate carrier under Part 395 follows the current federal hours-of-service and electronic logging device rules. The rule makes two changes to Part 395 itself: it deems the 395.1(k) planting and harvesting season to run January 1 through December 31 of each year, and it requires a driver exempted from 395.3 under 395.1(k) to keep a daily record of hours worked for the purpose of 395.8.
- ELD intrastate adoption: exceptions
- ARM 18.8.1502(2)(f) sets the 395.1(k) planting and harvesting season at January 1 through December 31 of each year. ARM 18.8.1502(2)(g) says a person exempted from 395.3 under the 395.1(k) exclusion must keep a daily record of the number of hours worked, in a format the record keeper chooses so long as it has an entry for hours worked by calendar day, retained six months from the initial entry date; payroll records or time sheets may be used if they are updated daily. ARM 18.8.1502(2)(e) puts drivers on a type 2 CDL who are not in interstate commerce under the state age and physical qualification rules in ARM 23.3.505 and 23.3.506 for Part 391.
Who issues permits
The Licensing and Permitting Section of MDT Motor Carrier Services in Helena issues every Montana size, weight and temporary permit. Its MT eTRIPS system lets carriers self-issue trip permits, term permits and GVW fees, and the permit desk answers by phone during business hours. After hours, any Motor Carrier Services weigh station can help. Superloads go to a separate superload inbox for district review.
A carrier that self-issues takes on the checking itself: construction reports, load and speed restrictions, and the 511 road conditions for the route.
The permit types Montana issues
Trip permits cover one move: oversize, doubles and triples, overweight on a bridge-formula basis priced by route distance, and excess axle weight priced by weight and miles. Term permits run the calendar year for oversize, long doubles, non-divisible length and triples, while term overweight permits run by the quarter. Seasonal permits add the wintertime weight allowance on non-interstate roads, the custom combine permit, and the implement dealer permit.
Trucks not licensed for Montana buy a temporary trip permit in place of registration and a temporary special fuel permit if they have no IFTA license.
Night, holidays, and bad roads
Wider loads can run around the clock on the interstate, while larger loads off the interstate move in daylight only. Holiday closures stretch across adjoining weekends, and Thanksgiving closes from Thursday through Sunday for loads over the holiday limits. No permitted load moves on a route placed under severe driving conditions, and a few named highways carry their own width and length limits.
Compare beyond Montana
Running multi-state loads? The trucking permits by state table shows which permit families and issuing offices apply in every jurisdiction, the oversize permit costs by state table compares limits and fees across all 51 jurisdictions, and the permit cost estimator prices a specific load per state.