Washington oversize permit requirements
Washington prints a warning on its permits that every carrier should read twice: a Washington oversize permit does not guarantee height clearances on the permitted route. The state routes the load and takes the fee, but the responsibility for whether it fits under the structures stays with the carrier. On a route full of older overpasses, that is not a formality.
The permit runs three days and must be obtained before entering the state — they are no longer sold at ports of entry, which removes the safety net that Kansas and Utah still offer. Daylight movement runs seven days a week, and a load within twelve feet of width, fourteen feet six of height and a hundred and five feet of length may run at night with proper lighting.
Peak-hour curfews apply through the Seattle–Everett corridor and at Tacoma, Olympia, Vancouver and Kelso. Seattle and Tacoma each require a separate validation for their city routes on top of the state permit, so an urban delivery is two pieces of paper. Routine permits reach a hundred and twenty-five feet of length, sixteen feet of width on multi-lane roads but only fourteen on two-lane, and sixteen feet of height, with gross weight to a hundred and thirty thousand pounds on seven axles. Rear overhang is measured from the centre of the last axle rather than from the end of the trailer — fifteen feet, measured the way Washington measures it.
Legal dimensions
At or under these figures, no oversize permit is required in Washington.
- Width
- 8′6″
- Height
- 14′0″
- Gross weight
- 80,000 lb
- Overhang
- 3′ front; 15′ rear, measured from the centre of the last axle
- Steer axle
- 600 lb per inch of tire width, to a maximum of 13,200 lb
- Single axle
- 20,000 lb
- Tandem
- 34,000 lb
- Tridem
- 42,000 lb at 8′ minimum spacing
Routine permit limits
Above legal dimensions and up to these figures, Washington issues a permit as routine business. Beyond them the load becomes a superload, reviewed case by case.
- Length
- 125′
- Width
- 16′ on multi-lane roads, 14′ on two-lane
- Height
- 16′
- 5 axles
- 99,000 lb
- 6 axles
- 114,700 lb
- 7 axles
- 130,000 lb
Escort requirements
A load reaching any of these figures needs an escort in Washington — the figure is the first size that requires one, so a load measuring exactly this much already needs it.
- Width
- 14′1″
- Height
- 14′6″
- Length
- 125′1″
When the load may move
Permit validity. Permits are valid for three days and must be obtained before entering the state. They are no longer sold at ports of entry.
Operating time. Daylight — half an hour before sunrise to half an hour after sunset — including Saturdays and Sundays. A load within 12′ wide, 14′6″ high and 105′ long may travel at night with proper lighting.
Restricted travel. Weekday time and width curfews apply through Seattle–Everett, Tacoma, Olympia, Vancouver and Kelso. Seattle and Tacoma each require separate validation for their city routes.
Worth knowing
- A Washington permit does not guarantee height clearances on the permitted route — the state says so explicitly, and the responsibility stays with the carrier.
- Permits are no longer available at ports of entry and must be arranged before entering the state.
- Seattle and Tacoma require separate validation for city routes.
- Rear overhang is measured from the centre of the last axle, not from the end of the trailer.
- Legal semitrailer length is 53′, or 56′ with a permit.
- A load over 200,000 lb, or beyond the routine dimensions, is a superload.
Washington permits, answered
Does a Washington permit guarantee my load will fit under the bridges?
No, and the state says so explicitly — a Washington permit does not guarantee height clearances on the permitted route. The carrier carries that responsibility.
Can I buy a Washington permit at the state line?
No. Permits are no longer sold at ports of entry and must be obtained before entering the state.
Can an oversize load travel at night in Washington?
Within 12′ wide, 14′6″ high and 105′ long, yes, with proper lighting.
Do I need extra paperwork for Seattle or Tacoma?
Yes — both require a separate validation for their city routes on top of the state permit.
How does Washington measure rear overhang?
From the centre of the last axle rather than from the end of the trailer, to a limit of 15′. The measuring point matters as much as the number.
Crossing more than Washington?
A permit is per state. If the route leaves Washington, these are the states it most likely enters.
Get a permit quote for Washington
Enter the load once and the estimator prices every state on the route, flags where an escort is required, and turns the quote into an order.
Price a permit for Washington →Compiled from published state DOT sources. Regulations change — confirm the current rules before dispatch. Last reviewed 2026-07-30.