Idaho OSOW permits

Updated: Sep 2

Permits valid for five days.

Idaho Permitting System:

Contact phone number: 1-208-334-8420


One-half hour before sunrise to one-half hour after sunset, including Saturdays and Sundays (the majority of routes). Up to and including 10' wide, 110' long or 14'6 high, travel is allowed 24/7 (the majority of routes) with lighting as specified on the permit.


If over 13' wide, movement prohibited between 6:30 – 8:30 a.m., 11:30 – 1:30 p.m., and 4:00 – 6:00 p.m. in Boise, Caldwell, Coeur d'Alene, Idaho Falls, Lewiston, Nampa, Pocatello, Twin Falls, Garden City, and Chubbuck. Holiday travel restrictions may depend on dimension. Check with the Sammons Permit Office.


Width: 8'6"

Height: 14'

Length: 53' semi-trailer on National Network, 48' trailer on non-N.N.

Overhang: 4' front, 10' rear

Weight: 80,000 Gross Single – 20,000 Tandem – 34,000 Tridem – depends on spacings

Steer – 600 pounds per inch of tread width (13,200 pounds with 11" tires).

Divisible Loads Exceeding 80,000: You can exceed 80,000 gross without a permit on state highways as long as you are legal on all axle/group weights and you are licensed for at least the amount of your gross weight. However, if you need any Interstate routes, you will need to get an Annual Excess Weight Permit.


Width: 16'

Height: 15'6

Length: 110'.

Weight: Single – 33,000 to 22,000* Tandem – 56,000 to 38,500* Tridem – 70,500 to 48,000*

Steer – 600 pounds per inch of tread width (13,200 pounds for 11" tires)

* Group weight maximums depend on route classification, with Interstate routes getting the highest.

Loads exceeding these dimensions or are considered as Super Loads.


On 2-Lane Highways:

Width: Over 12' – 1 escort; over 14' – 2 escorts; over 16' – may require 3 escorts

Height: Over 16' – 1 escort.

Length: Over 100' – 1 escort.

Overhang: Over 25' rear – 1 escort.

On Interstate System:

Width: Over 15' – 1 escort; over 16' – may require 2 or 3 escorts

Height: Over 16' – 1 escort.

Length: Over 120' – 1 escort.

Overhang: Over 25' rear – 1 escort.


All lift axles must be on the ground if exceeding legal axle weights. Blades, buckets, etc. may be taken off and hauled on the same load, depending on route and situation. The state will determine on a case-by-case basis.


Requirements are specified on the Idaho permit. "Oversize Load" signs are required on all overwidth loads. Flags are required on all four corners and extremities of overwidth loads and on rear overhang exceeding 4'. Overweight only loads do not require signs or flags.

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