Idaho oversize permit requirements
Idaho closes its cities to wide loads three times a day rather than twice. Alongside the usual morning and evening peaks — half past six to half past eight, and four to six — there is a midday ban from half past eleven until half past one. It applies to loads over thirteen feet wide in ten places: Boise, Caldwell, Coeur d'Alene, Idaho Falls, Lewiston, Nampa, Pocatello, Twin Falls, Garden City and Chubbuck. A wide load crossing the state has three windows to miss, not two.
Away from the cities Idaho is straightforward and fairly generous. Daylight movement runs seven days a week, and a load within ten feet of width, a hundred and ten feet of length and fourteen feet six of height may run around the clock with the specified lighting. The permit runs five days.
Permit axle allowances vary by route classification rather than sitting at a single figure, and the range is wide — a single axle from twenty-two thousand to thirty-three thousand pounds, a tridem from forty-eight thousand to seventy thousand five hundred, with the Interstate routes at the top. Routine limits reach a hundred and ten feet of length, sixteen feet of width and fifteen feet six of height. One equipment rule to note: every lift axle must be down if the load exceeds legal axle weights.
Legal dimensions
At or under these figures, no oversize permit is required in Idaho.
- Width
- 8′6″
- Height
- 14′0″
- Gross weight
- 80,000 lb
- Overhang
- 4′ front, 15′ rear
- Steer axle
- 600 lb per inch of tread width
- Single axle
- 20,000 lb
- Tandem
- 34,000 lb
Routine permit limits
Above legal dimensions and up to these figures, Idaho issues a permit as routine business. Beyond them the load becomes a superload, reviewed case by case.
- Length
- 110′
- Width
- 16′
- Height
- 15′6″
- Single axle
- 22,000–33,000 lb depending on route classification
- Tandem
- 38,500–56,000 lb depending on route classification
- Tridem
- 48,000–70,500 lb depending on route classification
Escort requirements
A load reaching any of these figures needs an escort in Idaho — the figure is the first size that requires one, so a load measuring exactly this much already needs it.
- Width
- 15′1″
- Height
- 15′0″
When the load may move
Permit validity. Permits are valid for five days.
Operating time. Daylight — half an hour before sunrise to half an hour after sunset — seven days a week. A load within 10′ wide, 110′ long and 14′6″ high may travel around the clock with the specified lighting.
Restricted travel. Loads over 13′ wide may not move 6:30–8:30 AM, 11:30 AM–1:30 PM or 4–6 PM in Boise, Caldwell, Coeur d'Alene, Idaho Falls, Lewiston, Nampa, Pocatello, Twin Falls, Garden City or Chubbuck.
Worth knowing
- The city curfew runs three times a day, including a midday ban from 11:30 AM to 1:30 PM, in ten named cities.
- Permit axle allowances vary by route classification, with Interstate routes at the top of the range.
- Every lift axle must be down if the load exceeds legal axle weights.
- Legal length is 53′ on the National Network and 48′ on non-designated routes.
Idaho permits, answered
Does Idaho have a midday curfew for wide loads?
Yes — 11:30 AM to 1:30 PM, on top of the 6:30–8:30 AM and 4–6 PM peaks, for loads over 13′ wide in ten cities including Boise, Coeur d'Alene and Twin Falls. Three windows to miss rather than two.
Can an oversize load travel at night in Idaho?
Within 10′ wide, 110′ long and 14′6″ high, yes — around the clock with the specified lighting.
Why do Idaho permit axle weights vary so much?
They are set by route classification rather than by a single statewide figure. A tridem runs from 48,000 lb to 70,500 lb depending on the road, with the Interstate at the top.
Do lift axles have to be down in Idaho?
Yes, every one of them, whenever the load exceeds legal axle weights.
How tall can a load be on an Idaho routine permit?
15′6″, with 16′ of width and 110′ of length.
Crossing more than Idaho?
A permit is per state. If the route leaves Idaho, these are the states it most likely enters.
Get a permit quote for Idaho
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 Idaho →Compiled from published state DOT sources. Regulations change — confirm the current rules before dispatch. Last reviewed 2026-07-30.