Washington Oversize & Overweight Permits
Over 8'6" wide, 14' high, 80,000 lb, or a 53' trailer, you buy a WSDOT permit (RCW 46.44.090). Run day or night up to 12' wide, 14'6" high, 105' long; wider or taller is daylight only. Pilot cars start at 14' wide on multilane, 11' on two-lane. Seattle, Tacoma, and Spokane close 6-9 a.m. and 3-7 p.m., and OS/OW parks from noon the day before six holidays.
When Washington needs a permit
Over 8'6" wide, 14' high, 80,000 lb, or a 53' trailer, you buy a WSDOT permit (RCW 46.44.090). Run day or night up to 12' wide, 14'6" high, 105' long; wider or taller is daylight only. Pilot cars start at 14' wide on multilane, 11' on two-lane. Seattle, Tacoma, and Spokane close 6-9 a.m. and 3-7 p.m., and OS/OW parks from noon the day before six holidays.
Thresholds, escorts, and curfews
- Legal max before a permit: Permit needed over 8'6" wide, 14' high, 80,000 lb, a single unit over 40', or a trailer over 53'.
- Escort / pilot car: On multilane: 1 escort over 14' wide, 2 over 20'. On two-lane: 1 escort over 11' wide, 2 when both a front and rear car are needed. Height over 14'6" needs a pole (height) car. Length over 125' on multilane (105' on two-lane) needs 1 escort. Excess rear overhang triggers one too.
- Superload: Superload over 16' wide, 16' high, a 125' load length, or 200,000 lb. Special handling with route review and structure analysis, not a routine self-issue.
- Travel curfew: Oversize is daylight only, a half hour before sunrise to a half hour after sunset. Loads up to 12' wide, 14'6" high, and 105' long may run at night with proper lighting. Seattle, Tacoma, and Spokane ban OS/OW 6-9 a.m. and 3-7 p.m. on weekdays. Holiday no-move runs from noon the day before New Year's, Memorial Day, Independence Day, Labor Day, Thanksgiving (plus the day after), and Christmas.
- Permit fee: Single-trip permits are modest (commonly around $10-$25+); overweight is priced by weight with a $14 minimum (RCW 46.44.0941). Annual single-trailer permit runs about $100/yr; overweight monthly options roughly $70 (3 axle) to $90 (4 axle).
Washington Oversize Permit FAQ
When do I need an oversize permit in Washington?
Does Washington require a pilot car or escort?
Can I move an oversize load at night or on weekends in Washington?
What does an oversize permit cost in Washington?
Reference information for planning, not legal advice. Traffic laws change and this can be out of date, so always confirm the current statute and obey posted signs before you rely on it. Last reviewed July 2026. Source: https://wsdot.wa.gov/travel/commercial-vehicles/commercial-vehicle-permits/permit-types-fees. See our Terms & Disclaimer.
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