Oversize load permits: when you need one, and how to get it right
Steve Woods · Lead Dispatcher, TruckSprint
Steve Woods leads the TruckSprint dispatch desk and reviews every guide we publish. How we research and update guides.
Updated October 2026
Quick answer
You need an oversize load permit when your vehicle or load exceeds legal limits: over 102 inches wide, over the state's height limit (most are 13 ft 6 in to 14 ft), over state length limits, or over 80,000 lb gross or axle limits. Permits come from each state on your route. Overweight permits on the Interstate are only for nondivisible loads.
Source: 23 CFR 658 and 49 CFR 393.87, eCFR · checked 2026-10
Oversize work pays for the extra planning, but every inch and every pound has to be accounted for before the wheels turn. I'm Steve, lead dispatcher at TruckSprint. Oversize is one of the eleven equipment lines we dispatch, and this guide covers the federal baseline every state builds on, plus what each state adds. Running without the right permit is never worth it: fines, a parked load and liability you can't afford.
What makes a load oversize
The federal rules set a floor that states build on:
| Dimension | Federal rule | Cite |
|---|---|---|
| Width | 102 inches on the National Network; states may permit wider | 23 CFR 658.15 |
| Height | No federal limit; most states 13 ft 6 in to 14 ft | FHWA (2004) |
| Length | States can't set less than 48 ft for a semitrailer, or limit the overall length of STAA combinations | 23 CFR 658.13 |
| Gross weight | 80,000 lb on the Interstate, plus axle limits and the Bridge Formula | 23 CFR 658.17 |
Source: FHWA, Federal Size Regulations for Commercial Motor Vehicles (FHWA-HOP-04-022, Oct 2004) · checked 2026-10
Many states allow longer trailers than 48 ft, and set their own height and length rules, so "legal" in one state may need a permit in the next. Check your load against the federal baseline:
Is this load oversize? EXAMPLE values
- WidthACTION
132 in is over the 102 in federal width. You need a permit from every state on the route.
- HeightOK
At or under 13 ft 6 in. Still check low clearances on the route.
- Gross weightOK
At or under the 80,000 lb federal gross. Check axle weights and the Bridge Formula too.
- Warning flags (393.87)ACTION
Flags at least 18 in square, red or orange fluorescent: mark the extremities on each side; 2 at the rear; placed to show the load's widest points.
Federal baseline only. Signs, lights, escorts, travel hours and holiday restrictions are set by each state permit office.
For axle weights, run the Bridge Formula calculator and the truck weight limit checker.
Nondivisible loads
The overweight side of permitting turns on one word. A load is nondivisible if splitting it would make it unable to do its job, destroy its value, or take more than 8 work-hours to take apart (23 CFR 658.5). On the Interstate, states can issue permits above the axle, gross and Bridge Formula limits only for nondivisible loads (658.17(h)).
So a 100,000 lb transformer can be permitted; 100,000 lb of steel plate generally can't, because you can split it into legal loads. Some states allow divisible-load permits on state roads under their own laws; check before you count on one.
What each state sets
States run their own permit programs, and the details differ:
- Permit types: single trip, annual or blanket, and superload permits for very large loads.
- Fees, often based on size, weight and miles; overweight fees can be charged per ton-mile.
- Travel hours: many states limit oversize moves to daylight, and restrict weekends and holidays. Our freight seasonality calendar marks the holiday weeks.
- Signs and lights: "OVERSIZE LOAD" banners and amber lights, with state-specific sizes and placement.
- Escorts: pilot cars or police escorts above certain widths, lengths and heights.
- Routes: the permit often names the exact route you must take.
Getting a permit, step by step
- Measure the loaded vehicle: width at the widest point, height at the highest point, overall length, overhangs, and every axle weight and spacing.
- Plan the route, with low clearances, bridges, construction and restricted roads checked.
- Apply to each state on the route, usually through its online permit system, or use a permit service.
- Read the permit before you leave. It lists the route, travel times, signs, escorts and any conditions.
- Carry the permit in the truck, and follow it exactly. A wrong turn off the permitted route can void it.
Flags, signs and escorts
Federal rules require warning flags on projecting loads (49 CFR 393.87): red or orange fluorescent flags at least 18 inches square on any load extending more than 4 inches past the sides or more than 4 feet past the rear. One flag at the rear if the projection is 2 feet wide or less; two if wider, placed to show the widest points.
Source: 49 CFR 393.87, eCFR · checked 2026-10
Signs, lights and escorts come from the states, and they're spelled out in each permit. Your securement still has to meet the general and commodity rules; see flatbed load securement.
Planning an oversize load
- Get exact dimensions from the shipper in writing, including the loaded height on your trailer. An estimate is how loads get stuck under bridges.
- Pick the right trailer. A step deck or lowboy can turn an over-height load into a legal-height one; see step deck dispatch.
- Price in the extras: permit fees, escorts, slower travel, daylight-only hours and possible waiting for permits.
- Build in time. Permits, especially superloads, can take days. Don't commit to a pickup before the permits are lined up.
- Know the holiday restrictions for every state on the route.
Mistakes to avoid
- Measuring the cargo, not the loaded vehicle. The permit is for the whole thing.
- Assuming one state's rules apply in the next.
- Leaving the permitted route.
- Treating divisible loads as nondivisible.
- Running at night or on a holiday when the permit says not to.
Oversize rewards the carriers who plan the whole move before they hook up.