Washington commercial vehicle weight limits follow the federal Interstate standard of 105,500 lbs gross, 20,000 lbs per single axle, and 34,000 lbs per tandem axle group. The federal bridge formula (23 U.S.C. 127) applies on all routes. Washington imposes seasonal weight restrictions on secondary roads during spring thaw, typically February through April. Mountain passes (Stevens Pass on US-2, Snoqualmie Pass on I-90, White Pass on US-12) have chain requirements October through May. Check WSDOT for current restricted routes and chain controls before routing. Oversize and overweight permits are available from WA DOT for loads exceeding standard limits. Verify current road-specific postings with the Washington DOT before routing heavy loads.
Washington imposes seasonal weight restrictions on secondary roads during spring thaw, typically February through April. Mountain passes (Stevens Pass on US-2, Snoqualmie Pass on I-90, White Pass on US-12) have chain requirements October through May. Check WSDOT for current restricted routes and chain controls before routing.
Check current restrictions at WA DOT →The federal bridge formula limits the weight on any group of axles based on the distance between the outermost axles in the group. It applies in Washington on all routes where federal standards apply.
W = maximum weight in lbs · L = axle spacing in feet · N = number of axles
WSDOT issues oversize/overweight permits through the Washington State Truck Permit System. Apply online at wsdot.wa.gov. Single-trip permits required for loads exceeding standard weight or dimension limits. Annual permits available for qualifying recurring heavy operations. Superloads require engineering review and route approval. Washington's Weight-Distance Tax registration is a separate requirement for heavy vehicle operators — register with Washington DOL.
Apply for Washington OS/OW Permit →Washington allows up to 105,500 lbs gross vehicle weight on designated state primary routes, and up to 48,000 lbs on qualifying tridem axle configurations. On Interstate highways, the federal standard of 80,000 lbs applies. Overweight permits from WSDOT are required for loads exceeding applicable limits. Washington also imposes a Weight-Distance Tax on heavy vehicles operating on state highways.
Washington's Weight-Distance Tax applies to commercial vehicles with a combined gross weight over 26,000 lbs operating on Washington state highways. The tax rate is based on the vehicle's registered gross weight and is calculated per mile traveled in Washington. Operators must register with the Washington DOL, maintain trip records, and file quarterly tax reports. Failure to register is a violation subject to significant penalties.
Yes. Washington imposes spring weight restrictions on secondary roads during the spring thaw period, typically February through April. Interstate highways and major state routes are generally not subject to spring restrictions. Secondary roads and rural routes may be posted with significantly reduced weight limits. Check WSDOT for current restrictions at wsdot.wa.gov before routing on secondary roads in early spring.
Washington oversize/overweight permits are issued by WSDOT through the Washington State Truck Permit System. Apply online at wsdot.wa.gov. Single-trip permits are required for loads exceeding weight or dimension limits. Annual permits are available for qualifying recurring operations. Superloads require engineering review and route approval. Remember that Washington's Weight-Distance Tax registration is a separate requirement from overweight permits.
Container loads from the Port of Seattle and Port of Tacoma must comply with standard Washington and federal weight limits on public roads. I-5 access routes near the ports are subject to standard federal Interstate limits (80,000 lbs). Overweight containers require a WSDOT overweight permit before leaving port property. Washington's Weight-Distance Tax applies to port drayage trips on state highways — drayage operators must be registered for WDT.
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The information on this page is compiled from publicly available government sources and is provided for general informational purposes only. TruckRadar is an independent search engine — we are not affiliated with any government agency and this content does not constitute legal or compliance advice. Regulations change frequently; always verify current requirements directly with the official source before making compliance decisions.
Official source: Washington WA Department of TransportationLast reviewed: 2026-04