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Oversize Overweight OS/OW Superload
53' trailer length,
8'6" wide, and
14' high
80,000 lbs
Exceeding legal
weight and dimension
150' long,
18' wide,
17' high and
180,000 lbs
Single Trip =
Flat Fee
Single Trip =
80,001-100,000 -
$3.50 per 25 mile
100,001-180,000 =
$70.00 + $3.50
per 5,000lbs
Single Fee =
OS Fee +

OW Fee
TBD upon review
of diagram showing
axle spacing and
tire size
When Escorts are Needed: # of Escorts:
On Interstate:
Width Over 16'6" 1 rear w/flag
On 2 Lane or Multi-lane Non-Interstate
Width over 12'6" up to 14' 1 front
Width main body of load over 14'
or overall width is over 15'
2 (front and rear)
Length over 110' 1 rear
If escort is required on non-interstate only (i.e. load dimension not over 16' wide or 120' long)
the load may travel within a 2-mile radius on interstate interchange without an escort
Width over 10' are not equipped with lights
and sign as state requires
2 (front and rear)
Height over 17' (before permit application) Route Survey
No more than 5 o/o loads needing escorts
may convoy if width is not over 14' or 15'
with projections and not over 120' long
2 (front and rear)
No more than 5 vehicles 2 (front and rear)
*for convoys, escort must have sign stating: Oversize load, convoy follows(#) of vehicles

Overhang Requirements:

Maximum legal overhang allowed is 3' (three feet) in front and 4' (four feet) in rear.
Overhang exceeding these dimensions will require an over length permit.

Police Escorts:

No police escorts are required in the state of Montana. Follow the standard escort requirements stated above.

Permits Valid For:

Single trip permit is valid for three (3) consecutive days

Operating Time

Continuous travel is allowed for loads that do not exceed 10' in wide 14'6" high 110' long (with overhang) 110'in length (without over hang on non-interstate). Non-reducible loads 10'0 or less may travel on the interstate system.

Daylight travel - Monday through Friday (excluding Holidays) travel is allowed during the hours of daylight, 7 days a week (excluding holidays and holiday weekends) providing the vehicle or load does not exceed 18' wide 120' long 18' high (over 17'high must have Helena approval). Vehicles hauling hay which exceeds 14'6" to 15' high and single vehicles exceeding 55' long are restricted to daylight travel.

Divisible Loads

Divisible loads may be permitted up to and including 14'6" high. These loads cannot exceed axle weights of more than 20,000 lbs, 34,000 lbs, or 42,000 lbs or even if gross weight is over 80,000lbs. Permits may be issued to haul reducible loads up to and including 9' wide, baled hay and hay racks may be permitted up to and including 9'6" wide. Travel is allowed 24 hours a day, 7 days a week on all highways including "red routes" and on holidays and holiday weekends. Loads exceeding 9' wide must be non-reducible. The only exception is baled hay, round bales and hay racks which may be hauled up to and including 12' wide. All travel is limited to daylight hours only. All restrictions for 12' wide loads apply to baled hay. Permits must be issued to haul reducible loads up to and including 95'. If there is any overhang then travel is restricted to daylight hours, 7 days a week except on "red routes" and holidays and holiday weekends. If there is no overhang travel is allowed 24 hours, 7 days a week on "red routes", holidays and holiday weekends. Loads exceeding 120' in length are not allowed to travel on Saturday, Sunday or holidays, or holiday weekends or on "red routes" after 3:00 p.m. on Friday until sunrise on Monday.


Blades and buckets may be hauled attached as long as the equipment is part of the load.

Restricted Travel

Travel is not allowed after 3:00 p.m. on Friday to Sunrise on Monday on highways indicated on the "red route" map.  A special permit is required to travel through billings. Restrictions will be listed on the permit. Each city determines its own restricted hours.

Spring Weight Restrictions

Normally from February 1st through June 31st, frost laws are set up by the Maintenance District 406-444-6157, speed limit and weight limit restrictions can be applied during frost laws, usually 8 tons on single axle and 600 lbs on steering axle

Superload Requirements

Loads in excess of routine issue limits shall submit an application including drawings, axle spacing and tire size to the state. Processing will take anywhere from two weeks to a month to receive permit.