Permits
Oversize and overweight permits
Past a state's legal width, height, length or weight, the load needs a permit for that state. Give us the dimensions and the route — we work out where you're over, price each state, and file them.
Where legal ends
Federal law sets width, gross weight and axle weights on the Interstate System and federal truck routes. It sets no height limit at all, and for semi-trailer length only a minimum that states must allow. Every state sets its own limits on its own roads, and the weight you can carry also depends on how your axles are spaced.
| Federal rule | Limit |
|---|---|
| Width | 8' 6" (102 inches) |
| Height | None. Each state sets its own |
| Length, semi-trailer | At least 48'. States set the maximum |
| Gross weight | 80,000 lbs on the Interstate System |
| Single axle | 20,000 lbs |
| Tandem axle | 34,000 lbs |
Where states actually differ
Width and gross weight are the same in all 51 states we cover — 102 inches and 80,000 lbs. If you are over on either, you are over everywhere. What changes at a state line is height, trailer length and what the axles may carry.
- 20
- of 51 states allow more height than 13' 6"
- 5
- of 51 states allow a semi-trailer longer than 53'
- 11
- of 51 states allow more than 34,000 lbs on a tandem
So a load can be legal in one state and need a permit in the next on height, length or axle weight alone. The applications ask for different things as well: some states want axle weights and spacings on every oversize application, even for a load that is only too tall, and others ask for them only when the load is overweight. Each state's full table — including overhangs and single, tandem and tridem axles — is on its state page.
One set of dimensions, checked against every state
Enter the load's length, width, height and gross weight once. Every state on the route is checked against its own legal limits, and an oversize or overweight permit is added in each state where you're over.
That matters most on a long haul. A load a few inches over 13' 6" is legal across much of the West and needs a permit across much of the East, and the quote sorts the route out state by state.
What comes with the permit
An OS/OW permit is not just permission — it is a set of conditions, and they are the state's, not ours.
A route, not a road map
The state approves specific roads, chosen around bridges, clearances and construction. Leaving the permitted route voids the permit.
Travel windows
Daylight only in many states, with curfews through rush hour, weekends and holidays, and hard stops for high wind or poor visibility.
Escorts and signage
Pilot cars front, rear or both past certain dimensions — police for the largest moves — plus flags, banners and lights. You arrange and pay for escorts separately.
Non-divisible, or it doesn't qualify
Oversize and overweight permits exist for loads that cannot be made smaller — a transformer, an excavator, a beam. If a load could reasonably be split into two legal loads, states expect you to split it rather than permit it. The federal test is roughly that taking it apart would damage it, destroy its value, or take more than about eight work hours.
Superloads are the far end of the same scale — very roughly past 16 feet wide or high, or into the hundreds of thousands of pounds, with each state drawing its own line. They need engineering review, bridge analysis and sometimes a physical route survey, so they take days or weeks and are quoted by hand. Call us early on one of those.
Common questions
- What counts as an oversize or overweight load?
- Anything past a state's legal limits. Two of those are the same in every state we cover: federal law sets width at 8 feet 6 inches and gross weight at 80,000 lbs. There is no federal height limit, so each state sets its own, from 13 feet 6 inches across much of the East to 14 feet or more in much of the West. Federal law sets only a minimum semi-trailer length, and states allow from 48 to about 60 feet. Axle limits on the Interstate are federal (20,000 lbs single, 34,000 lbs tandem), and what a group of axles may carry also depends on how far apart they are.
- What is a non-divisible load?
- A load that cannot be taken apart without damaging it, destroying its value, or taking more than about eight work hours. Only non-divisible loads qualify for oversize and overweight permits under the federal rules. If your load can reasonably be split into two legal loads, states expect you to split it.
- When does a load become a superload?
- When it exceeds the thresholds a state handles routinely — commonly around 16 feet wide or high, or weights in the low hundreds of thousands of pounds, though every state draws the line differently. Superloads need engineering review: route analysis, bridge calculations and sometimes a survey. Expect days to weeks rather than minutes.
- Do I need escorts or pilot cars?
- Often, and it is the state that decides. Thresholds vary: some require a rear escort past a given width, some front and rear, and the largest moves may need police. The permit spells out what your move requires. Escorts are arranged and paid for by you, separately from the permit.
- Can I run any route with an OS/OW permit?
- No. Permits are routed. The state approves specific roads, and travel is usually restricted by time of day, day of week, holidays and weather — many states prohibit oversize movement at night, in high wind, or through weekend and holiday windows. Running off the permitted route voids the permit.
- Which states on my route need an oversize permit?
- The ones where the load is over that state's limits. Enter the dimensions and gross weight in our quote and each state on the route is checked separately; the oversize/overweight permit is added in every state where you're over.