To keep the roadways as safe as possible, the state puts certain laws in place to encourage a smooth flow of traffic. One such law that applies to commercial vehicles is a left-lane restriction.
According to the Washington State Commercial Vehicle Guide, the left-lane restrictions apply to a range of vehicles that fit specific criteria, which does include more than just commercial vehicles.
The left-lane restrictions apply to any vehicle that weighs 10,000 pounds or more. It also applies to any vehicle towing a trailer regardless of weight.
The left-lane restrictions apply to limited access roadways with at least three lanes going in one direction, such as I-405, I-90 and I-5. The restrictions are not applicable in high occupancy vehicle lanes in most cases. There will be road signs alerting you to the restrictions in the applicable areas.
The left-lane restrictions state that you cannot drive your vehicle in the left-hand lane of the roadway. Another part of the rules is that commercial vehicles with a weight of 10,000 pounds or more cannot drive in high occupancy lanes at any time. If you are driving in the left lane when you should not be, you are subject to a citation.
There are some exceptions to the left-lane restrictions. The rules do not apply if you need to exit the road or when you need to make a left-hand turn.
The restrictions in the left lane of busy roadways help to keep slower moving vehicles to the right, allowing faster traffic to have a clear path without delays that require lane switching to get around.