Permits are valid for 5 days.
Travel is allowed one-half hour before sunrise to one-half hour after sunset, including Saturdays and Sundays (majority of routes). Up to and including 10′ wide, 120′ long or 14’6 high, travel is allowed 24/7 (majority of routes) with lighting as specified on permit. Weekend travel is allowed on majority of routes during daytime hours.
If load is over 13′ wide, movement is prohibited between 6:30 a.m. – 8:30 a.m., and 4:00 p.m. – 6:00 p.m. in most major cities. Holiday travel restrictions depends on dimension and route
Length: 53′ semi-trailer on National Network, 48′ trailer on non-National Network (“non-designated”) Note: Several 2-lane highways in Idaho are non-designated, including US-12 except in the Lewiston to Spalding, US-93 from Salmon to Challis, and US-95 from Council to Grangeville. For divisible loads, trailers exceeding 48’ are only allowed with an annual extra length permit, and the tractor-trailer off-track measurement must not exceed 5’6″ (3.00 on a few mountain routes). Non-divisible loads are covered by single or annual permit, without regard to off-track amount.
Overhang: 4′ front, 10′ rear
Weight: 80,000 Gross; Single – 20,000; Tandem – 34,000; Tridem – depends on spacing; Steer – 600 pounds per inch of tread width (13,200 pounds with 11″ tires).
ROUTINE PERMIT LIMITS:
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 are considered Super Loads.
Width: On 2-Lane Highways: Over 12′ – 1 escort; over 14′ – 2 escorts; over 16′ – may require 3 escorts
On Interstate System: Over 15′ – 1 escort; over 16′ – may require 2 or 3 escorts
Height: Over 16′ – 1 escort.
Length: On 2-Lane Highways: Over 100′ – 1 escort.
On Interstate System: 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. State will determine on a case-by-case basis.
Requirements are specified on Idaho permit. “Oversize Load” signs are required on all over width loads. Flags are required on all four corners and extremities of over width loads and on rear overhang exceeding 4′. Overweight only loads do not require signs or flags.