Federal regulations
Washington has adopted
Part 392 of the Federal Regulations.
Applicability
Part 392 applies to vehicles with a gross vehicle weight rating or gross combination weight rating or gross weight or gross combination weight of 10,001 or more pounds and vehicles transporting hazardous materials requiring placards.
Speed limit
The speed limit is 60 mph on rural interstates for all vehicles over 10,000 pounds gross weight and vehicles in combination (excluding auto stages); 55–60 mph day or night on all other highways, except where lower limits are posted.
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