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Q&A: Left lane semi-trucks, lane sweeping, and school bus etiquette

Is it okay if semi trucks camp in the left lane? (MyNorthwest image)

We’re getting close to back-to-school time so I thought I would open up the grab bag to celebrate the end of summer.

Semi-trucks camping in left lanes

KIRO listener Lisa hit me up about semi-trucks camping in the left lane.

Lisa wrote, “I commute from Covington to Bellevue every weekday for work. It frequently seems like backups are caused by slow semi-trucks driving in the left lane. Traffic will be clear in front of the semi, but very congested behind the truck. The left lane semi is also usually going the same speed as a right lane semi, which creates an additional slowdown because no one can pass either vehicle. Why does WA allow semi’s to drive in the left lane? It seems like traffic would flow better if semis were regulated to the right lane only.”

This is a popular question. Semi trucks in the left lane cause a lot of frustration for drivers. The law is clear. No vehicle towing a trailer or combo over 10,000 pounds can use the left lane on roads where there are three or more lanes traveling in the same direction. The HOV lane does not count. On Lisa’s drive, there are two general purpose lanes and an HOV lane. Semi trucks are allowed in that left lane.

There is also an exemption for big rigs in the left lane on roads with three or more lanes. They are designated areas around the state for ease of commerce, like I-5 between Southcenter and Everett or on I-90.

Lane sweeping

Lane sweeping is another topic I get asked about all the time. That’s what you call it when a driver makes a turn onto a road and crosses several lanes of traffic. This is illegal and dangerous. By law, drivers must turn into the closest lane, establish themselves in that lane and signal before moving to another lane.

You see this all the time at left turn signals where drivers make a left and immediately move all the way to the right-hand side of the road. This is extremely dangerous when there are multiple cars turning left. For example, if the car in front turns correctly, into the left lane and the car behind sweeps to the right lane. The first car then tries to get over and the second car is trying to speed by. The second car would be at-fault.

Passing a school bus

When can you pass a school bus? This always generates comments on the text line (98973), but people keep asking me about it.

There are plenty of times where you can pass a school bus with its lights and paddle out. Drivers get frustrated when others stop, unnecessarily. That said, you should take extreme caution around buses because kids do unexpected things and no one wants to see a child get hurt.

You must stop when you are going the same direction as the stopped school bus. You must stop if you are opposite the bus at an intersection. You must stop if it’s on the opposite side of a two lane road.

You do not have to stop when the bus is going in the opposite direction on roads with three or more lanes. A yellow-dotted left turn lane in the middle of the road counts as a lane in this calculation — you do not need to stop. You also don’t have to stop if that road is separated by a barrier or a median.

Read more of Chris’ Chokepoint stories

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