Montana oversize load rules
Legal limits, pilot car requirements, travel restrictions, superload thresholds and permit fees for oversize and overweight loads in Montana.
Legal limits without a permit
| Width | 8′6″ |
|---|---|
| Height | 14′ |
| Length | 55′ single vehicle · 53′ semitrailer · 75′ truck and trailer combinations |
| Weight | 80,000 lb; MDT does not require a special permit above 80,000 lb when the load is reducible and meets the bridge formula |
At a glance
| Escorts | 8 escort rules, starting at 12′6″ wide |
|---|---|
| Superload | 3 review triggers (height, length, width) |
| Travel | 5 restrictions (curfews, night, holidays) |
| Fees | 5 published fee lines |
Escort (pilot car) requirements
- 8 width, height and length thresholds with the escort count for each
- Overhang and route-type conditions
Travel restrictions
- 5 restrictions: curfews, night travel, weekends and holidays
- Which ones apply to a given load size
Superloads
- Exact thresholds and what the state requires past them
- Lead times, route surveys and police escort conditions
Permit fees
- 5 published fee lines with links to the fee schedule
- Validity periods and add-on charges
Common questions
When does Montana require a pilot car?
On non-Interstate highways over 12′6″ wide (front), over 16′6″ (front and rear), over 18′ (two front, one rear), over 150′ long (rear) and over 200′ (front and rear). On Interstates over 16′6″ wide (rear), over 18′ (two rear) and over 17′ high (front with pole).
What is a superload in Montana?
Over 18′ wide, 17′ high or 150′ long, or anything needing Bridge Bureau review. Class 1 approvals take up to two working days, Class 2 up to five.
Can oversize loads run at night in Montana?
On Interstates, yes up to 18′ wide with full lighting. On other highways only up to 10′ wide, 150′ long and 15′6″ high.
Sources
- MDT Permitting FAQ (legal limits, pilot vehicles, fees, superloads)
- MDT Permit Restrictions (eTRIPs restriction text: travel hours, holidays, pilot vehicles)
- ARM 18.8.509, special permit restrictions and super-load permits
- ARM 18.8.510A, pilot vehicle regulations and equipment
Planning reference. Permits carry their own conditions, and city and county roads have separate rules. Confirm with the Montana DOT Motor Carrier Services (Helena) before moving a load. Found an error? Report it.
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