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Montana Oversize Load / Pilot Car Requirements Revised 9/25/2020

  1. When is an oversize load permit required in Montana?

    Width: Over 8' 6"

    Height: Over 14' 0"

    Length: Semi-trailer over 53' 0"

    Weight: Over 80,000 lbs. GVW (20,000 lbs. single axle or 34,000 lbs. tandem axle)

  2. What are the oversize load times of movement?

    Continuous travel allowed on secondary roads 24 hours per day, 7 days per week, up to 10 feet wide, 150 feet long, or 15 feet 6 inches high.  Loads exceeding 10 wide, 150 feet long, or 15 feet 6 inches high are limited to daylight travel only.

    Daylight travel Monday through Friday only for loads that exceed 10′ wide, 150′ long and 15' 6"′ high (exceptions are implements of husbandry).

    Travel prohibited on New Years Day, Independence Day, Labor Day, Thanksgiving Day & Christmas Day (if holiday falls on weekend or Friday, travel prohibited Friday through Sunday. If holiday falls on Monday, travel prohibited Saturday through Monday. Thanksgiving holiday prohibits travel on Thursday through Sunday. 

  3. When is a Montana pilot car / escort vehicle required on 2 lane or multi-lane, non-interstate?

    Over 10′ wide (not equipped with lights & signs) requires 2 pilot cars.

    Over 12′ 6″ to 16′ 6″ wide requires 1 pilot car.

    Over 16′ 6" wide to 18' wide requires 2 pilot cars.

    Over 150′ long requires 1 pilot car over 200' long require 2 pilot cars 1 front and 1 back.

    Over 17′ high with route survey requires 1 pilot car with height pole

  4. When is a Montana pilot car / escort vehicle required on the interstate?

    Over 16′ 6″  to 18' wide requires 1 pilot car,  18' or wider must have at least 2 traveling side by side.

    Loads exceeding 17' high to 24' high must have a front pilot car equiped with a high pole.  Loads exceeding 24' high must have 1 font pliot car with a high pole and a rear pilot car.

  5. When is a Montana pilot car / escort vehicle required for a convoy?

    No more than 5 OS/OW loads requiring escorts may convoy if width not over 14′ (15′ with projections and not over 120′ long).

    No more than 5 OS/OW loads may convoy if length of any unit is greater than 110′ long on interstate highways.

  6. What are section 17 requirements?

    Before crossing any non interstate structure or structures the overweight vehicle must slow down to 10 mph before and centerline all bridges.  A minimum of 2 pilot vehicles are required one front and one rear.  No simultanious vehicles are to be on the bridge with the overweight load. 

  7. What are section 18 requirements?

    Bridge slowdown and speed restrictions on all highways; loads may not exceed 55 mph or posted speed limits whichever is less, only one overweight vehicle allowed on the bridge at a time, stopping or shifting gears on any bridge is prohibited.  Non-interstate daylight hours only, must reduce speed to 10 mph while crossing bridges remaining in the driving lane and provide  a minimum of 1 pilot vehicle.

  8. What is the contact information for the Montana Department of Transportation?

    Phone Numbers, Addresses and Websites:

    Montana Road Conditions: (800) 226-7623

    Montana State Police: (406) 841-7000

    Oversize Permits: (406) 444-6130   Fax: (406) 444-0800

    Trip / Fuel Permits: (406) 444-6130


    Dept. of Transportation

    Motor Carrier Service Division

    P.O. Box 4639

    Helena, MT   59604

     Web Sites

    Montana DOT Website -

    Current Road Conditions -

    Coast 2 Coast Online Permits -

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