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
These are the federal baselines on the Interstate System. They are the number most people quote, and they are not the number you are held to — 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 baseline | Limit |
|---|---|
| Width | 8' 6" (102 inches) |
| Height | 13' 6" (many states allow 14') |
| Length, semi-trailer | 48'–53', set by state |
| 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 clear one state and need a permit in the next on height or axle weight alone. Each state's full table — including overhangs and single, tandem and tridem axles — is on its state page.
We tell you you're oversize. You don't have to know first.
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 wherever you exceed them — with a note saying which limit you crossed and by how much.
It is the most useful thing the software does, and it is the thing carriers most often get wrong. A load that ran legal last month can be over this month because you changed trailers.
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. The federal baseline on the Interstate System is 8 feet 6 inches wide, 13 feet 6 inches high and 80,000 lbs gross, with semi-trailer length usually 48 to 53 feet. States set their own numbers on their own roads and many differ — several allow 14 feet of height, and weight limits move with your axle spacing.
- 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.
- How do I know if I'm even oversize?
- Enter your dimensions and weight in our quote and we compare them against every state on your route. Where you exceed a state's limits we add the permit automatically and tell you why. Most of our customers find out they are oversize from us.