Rules of the Road

You’re on a three-lane highway and trying to keep a steady speed. Which lane should you choose?

Northbound traffic on Interstate Highway 5 moves slowly toward downtown Seattle on Aug. 8, 2007.
Northbound traffic on Interstate Highway 5 moves slowly toward downtown Seattle on Aug. 8, 2007. AP

Question: My friend and I have a disagreement. On a three-lane highway with very light traffic, which lane should a 60 mph driver choose? I say the far right.

My friend says the middle. My reasoning is because if I'm going 65 mph and need to pass the middle lane driver, I am required to pass on the left. Meanwhile, the right lane is wide open and it's discourteous for the 60 mph car to be camping out in the middle lane. Slower traffic keep right, correct? My friend says the middle lane is a thru lane and if you're going the speed limit, it’s fine to be there.

The second part to this question: There is a 60 mph car in the middle lane. I am going 65 mph in the right lane. Do I pass him on the right? Or should I pass on the far left?

Answer: First of all, if 60 mph is the speed limit, why are you openly admitting to speeding in a question to a traffic safety guy? I’ll do my best to set that aside for a moment to answer the question.

I think I can help settle this disagreement. It’s common, when discussing traffic rules, to mix up courtesy, reason, what your neighbor says (and he swears he’s friends with an ex-cop), and the law, ending up with a result that is a mix of truth and error. In the case of driving in the middle lane because it’s the “thru lane,” that might be a common term for it, but you won’t find it in the Revised Code of Washington.

The section of the law that addresses this situation is titled, “Keep right except when passing, etc.” The title itself pretty much gives away the answer. As a side comment, I like that it has “etcetera” included in the title – like it’s telling you, “I’m going to explain the rule about keeping right, and then I’m going to add some other stuff.”

On a three-lane freeway, the rules are the same as a two-lane freeway: drive in the furthest right lane “available for traffic.” I understand that term to mean that there’s enough room for you in the lane. We’re not trying to squeeze all of rush hour traffic into one lane. You can tell your friend you’re right. At least most of the time. There are a few exceptions. Drivers can use other freeway lanes when:

▪  overtaking and passing another vehicle,

▪  traveling at a speed greater than the traffic flow (that’s not permission to speed),

▪  moving left to allow traffic to merge,

▪  preparing for a left turn (on the freeway this would be the rare left-side off-ramp).

Camping out in the middle lane when there is room to move right and none of the exceptions apply would be a violation of the law. Is it a big deal if the traffic is, as you described, very light? Maybe not, but the original question wasn’t how many people it would annoy, but if it’s legal.

In response to the second part of your question, you can legally pass a car in the center lane on the left or the right. Here are a couple things to consider as you decide:

▪  where a driver expects to be passed,

▪  increased risk with each lane change.

As drivers, we expect faster traffic to pass us on the left, so if you were directly behind the car, I’d recommend passing on the left. However, if you’re in the right lane, passing on the left would require two lane changes to pass, and two more lane changes to get back to the right lane. Each lane change is an additional opportunity for two cars to try to occupy the same space. Rather than tell you what to do, I’ll recommend choosing the route that you think will be safest given the circumstances as you plan to pass.

I mentioned the “etcetera” part of the law earlier. Here’s one interesting bit you can propose to your guests at your holiday party: The car pool lane is not considered the left lane of the roadway. I know that clarification is in there to exempt drivers in the car pool lane from the “keep right except to pass” law, but if it’s not the left-hand lane, how would you describe it? The lane just to the left of the left-hand lane? Wouldn’t that just be the left-hand lane?

Road Rules is a regular column on road laws, safe driving habits and general police practices. Doug Dahl is the Target Zero Manager for the Whatcom County Traffic Safety Task Force. Target Zero is Washington’s vision to reduce traffic fatalities and serious injuries to zero by 2030. For more traffic safety information visit Ask a question.