Rules of the Road

Who has the right of way on a freeway on-ramp? It’s all about geometry

Right of way at a typical four-way intersection is pretty easy to understand. It gets tricky though, when you encounter a painted traffic island that creates an offset right-turn lane, or a channelized right turn lane.
Right of way at a typical four-way intersection is pretty easy to understand. It gets tricky though, when you encounter a painted traffic island that creates an offset right-turn lane, or a channelized right turn lane. The Bellingham Herald file

Question: Would you please explain the reason why the right turn onto the freeway on-ramp must yield to the left turning vehicle? Example: Bakerview and Interstate 5 southbound on-ramp.

Answer: This question is sort of a geometry problem, so I’m going to draw a diagram to help explain it.

But before I get to that, let’s take a look at the law that is probably causing the question-asker’s confusion. RCW 46.61.185 states that a driver intending to turn left in an intersection shall yield the right-of-way to any oncoming vehicle.

At a typical four-way intersection that’s pretty easy to understand.

It gets tricky, though, when you encounter a painted traffic island that creates an offset right-turn lane, or a channelized right turn lane. (That’s the engineer’s term for the lane separated by that little raised triangle that lets you make a right turn before reaching the main intersection.)

In the example of Bakerview and the I-5 southbound on-ramp we have a painted traffic island. To understand how that affects right-of-way, we should review the definition of an intersection. The RCW begins by stating (in part one of the section) that an intersection is “the area embraced within the prolongation or connection of the lateral curb lines . . .”

Did your brain just glaze over as you read that? Mine did.

Fortunately it goes on to explain that an intersection is wherever two roads meet. In part two of the definition of an intersection, the law adds a clarification with more confusing terminology that, as I understand it, means that when there is at least 30 feet between where roads connect (like at a traffic island or channelized right turn), each junction should be considered a separate intersection.

Now that we have that covered, let’s take a look at a diagram modeled roughly on the Bakerview/I-5 onramp mentioned earlier.

0903 Road Rules (4)

Essentially, that traffic island creates three little intersections. At intersection one a car traveling eastbound can freely make a right turn onto the onramp. At intersection two, a car traveling westbound intending to make a left onto the onramp would need to yield to oncoming traffic (as required by the RCW we looked at earlier). At intersection three the car that has just made a right turn from the eastbound lane is now in a merging lane and has to yield to traffic already in the lane that they want to merge into. This requirement is laid out in RCW 46.61.140, which states that a driver can’t (okay sure, you could, but you’d be breaking the law) change lanes “until the driver has first ascertained that such movement can be made with safety.”

You might be asking yourself, “How can anyone that’s not a complete traffic nerd know all the definitions about intersections and who yields to whom?” That’s a fair question. Just remember that no matter who is required to yield, everyone who uses the road has the responsibility (and legal obligation) to do what they can to be safe and avoid a collision. It takes all of us working together to get where we’re going safely.

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 TheWiseDrive.com. Ask a question.

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