Washington Oversize Permits
Washington oversize permits are valid for 3 days. Must have the overweight permit prior to entering the state.

Operating time
Travel is allowed one half hour before sunrise to one-half hour after sunset, including Saturdays and Sundays. Vehicle/loads not exceeding 12′ wide, 14’6″ high and 105′ long, including legal overhangs, are allowed to travel at night with proper lighting.

Restrictions
Weekday curfew restrictions for the cities of Seattle-Everett, Tacoma, Olympia, Vancouver, Kelso and Spokane are listed on the Commuter Curfew Hours sheet which accompanies permits. No travel allowed starting noon the day prior to a major holiday until one-half hour before sunrise the day after a holiday and some holiday weekends.

Speed Limit

60 mph. unless otherwise specified on permit.

Legal dimensions
The vehicle must have the following characteristics:

Width: 8’6″
Height: 14′
Length: 53′ semi-trailer (a 56′ trailer and load permit is available for legal loads)
Overhang: 3′ front, 15′ rear from center last axle to end of load
Weight: 80,000 Gross; Steer – 600 lbs. per inch of width; Single – 20,000; Tandem – 34,000; Tridem – 42,000 (with at least 8′ of axle spacing)
Routine permit limits
Width: 16′
Height: 16′
Length: 125′ trailer and load
Weight: Single – 22,000; Tandem – 43,000
Note: Washington state oversize permits do not guarantee height clearances on permitted routes.

Escorts
On Multiple Lane Highways:

Width: Over 14′ – 1 escort; over 20′ – 2 escorts
Height: Over 14’6″ – 1 escort with height pole
Length: Trailer length including load over 125′ – 1 escort
On 2-Lane Highways:

Width: Over 11′ – 2 escorts
Height: Over 14’6″ – 1 escort with height pole
Length: Trailer length including load over 105′ – 1 escort
Overhang: rear overhang exceeds 1/3 of total trailer and load length – 1 escort; front overhang of 20′ measured from center of steering axle to front of load – 1 escort

Security measures
“Oversize Load” signs are required on all over dimensional loads. Flags must be displayed on all four corners of all over width loads, and at the extreme ends of all protrusions, projections, or overhangs.

When night movement is allowed, loads projecting beyond the sides of the vehicle must have amber lights visible from the front and side at the outermost extremities. Rearmost edge of the projecting load must be marked with a red lamp visible from the rear and side.