Rules of the Road

We all should know red, yellow and green. Here’s what the flashing yellow arrow means

Unlike a solid yellow light, which warns that a red light is coming, the flashing yellow, such as this one on Bakerview Road, reminds drivers to be careful going through an intersection.
Unlike a solid yellow light, which warns that a red light is coming, the flashing yellow, such as this one on Bakerview Road, reminds drivers to be careful going through an intersection. Courtesy to The Bellingham Herald

Question: I have a question about the lights on Bakerview Road at south-bound Interstate 5, exit 258. When you are in the left turn lane there is a flashing yellow arrow that comes on, then it turns to solid yellow. I have stopped on the yellow arrow, both when it is flashing and/or solid, and there are a lot of people who go through on it. The other day I got there just after the signal had changed to red, then while I was waiting for the green arrow the light changed to the flashing yellow arrow again. What should a person do?

Answer: I can understand the confusion. For many years we’ve been conditioned to see a yellow signal in a set of traffic lights as a warning that the signal is switching from green to red. Now they add a flashing yellow, and we don’t know what it means.

In many areas of life, good ideas get replaced by better ones. That’s certainly true with traffic safety and road engineering. Sometimes though, a better traffic control idea gets implemented, but there’s no mechanism in place to teach drivers what it means or how to use it.

I remember when the Department of Transportation began installing roundabouts in Whatcom County. They printed fliers, created instructional videos and got as much media exposure as they could. They even made a vinyl mat the size of a living room with a roundabout printed on it and brought it to fairs and festivals around Whatcom County, where they encouraged people to walk through the roundabout to get the hang of how to use them.

Even with all the effort to teach people how to use them, it still took a while for drivers to understand roundabouts. Some of you will respond that a lot of drivers still don’t understand roundabouts.

Now we have flashing yellow lights, but no fliers, instructional videos or living room-sized intersections to explain a flashing yellow arrow, so I’ll do my best to be a substitute for a massive public information campaign.

Unlike a solid yellow light, which warns you that the red light is coming soon, the flashing yellow is more of a reminder to be careful as you go through the intersection.

The Revised Code of Washington calls a flashing yellow light a caution signal and states that a driver must proceed with, as you might expect, caution. In the case of a flashing yellow left turn arrow, it’s letting you know that the oncoming traffic has a green light, so you can go if there is an opportunity, but you need to yield to the oncoming cars.

You’ll find flashing yellow lights on left turn lanes with a traffic signal dedicated to that lane.

Flashing Yellow Signal
Doug Dahl Courtesy to The Bellingham Herald

You might be asking yourself why we needed a flashing yellow turn light when, even with a solid green light, drivers are supposed to yield to oncoming traffic before making a left turn. The answer is that, collectively, we’re not that good at driving; too many drivers were thinking “green means go” and driving into oncoming traffic. Studies have shown that the flashing yellow light has reduced crashes from left-turning drivers failing to yield to oncoming vehicles.

There’s a second benefit to the flashing yellow left signal: intersection efficiency. The flashing yellow gives traffic engineers additional flexibility on how to control traffic flow in busy intersections. Having a flashing yellow option moves more cars safely through the intersection than a signal that only has a green light.

This question also brings up an issue about driver training. When I got my driver license more than 30 years ago, my driver’s ed teacher couldn’t have anticipated the changes that would happen in driving over the course of several decades.

As laws change or intersections get new designs, how can we expect drivers to know what to do?

Even though I know a lot of people don’t like this idea, there’s some merit to requiring ongoing driver training. Wouldn’t a refresher class make sense in order to renew a driver license? We’re giving ourselves the privilege of driving two-ton missiles through our neighborhoods; we should make sure we all know how to navigate them.

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.