Washington Truck Weight Limits

How much a truck can weigh in Washington

On the Interstate you get the federal 80,000 pounds. Off the Interstate Washington's weight table runs higher - a long, properly-spaced rig can legally gross up to 105,500 pounds (RCW 46.44.041), and WSDOT can extend the table to 115,000 on designated routes. Single axle stays 20,000, tandem 34,000. Fines start at 3 cents a pound and climb fast (RCW 46.44.105).

Axles, off-Interstate, and permits

• Off the Interstate: Up to 105,500 lb on the statutory weight table for a long-wheelbase, properly-spaced combination (7+ axles); WSDOT may extend the table to 115,000 lb on designated state highways
• Single axle: 20,000 lb
• Tandem axle: 34,000 lb (two tandem sets may each carry 34,000 lb if the first and last axles are 36 ft or more apart)
• With a permit: 105,500 lb on the RCW 46.44.041 weight table; WSDOT/local authorities may extend the table to 115,000 lb on designated routes. Superloads by special permit.
• The 105,500-lb figure is the statutory weight-table maximum, not a special permit; the Port of Tacoma heavy-haul corridor also runs at 105,500.

Posted bridge and road limits

Bridges and local roads are posted with MUTCD R12 signs. 'WEIGHT LIMIT X TONS' means short tons of 2,000 lb, so 10 TONS = 20,000 lb. A posted limit overrides your legal weight - an 80,000-lb legal load still cannot cross a bridge posted lower, and you detour. Crossing a load-posted bridge over its limit is a separate violation, and the carrier can be billed for inspection and structural repair if the crossing damages the span.

What running heavy costs

RCW 46.44.105 graduates by pounds over: 1-4,000 over = 3 cents/lb; 4,001-10,000 over = $120 + 12 cents/lb over 4,000; 10,001-15,000 over = $840 + 16 cents/lb over 10,000; 15,001-20,000 over = $1,640 + 20 cents/lb over 15,000; 20,001 lb and over sits in the top bracket at a higher per-pound rate. A base traffic infraction adds no less than $50 (first offense), $75 (second), $100 (third).

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