Sullivan: Drivers slow to understand zipper merge, would better signs help?

Jun 13, 2024, 5:59 AM | Updated: 6:00 am

Why are so many drivers slow to pick up and use the zipper merge?

I have reported for years about the lack of general merging etiquette in the Pacific Northwest and how it contributes to our terrible congestion. I have also lamented the lack of merging skills taught to young drivers. There is less than a half page on merging in the Driver’s Guide.

Why am I on my high horse again today?

I have been traveling back and forth to the beach the last few weekends, and I have been experiencing the long backups on US 12 and SR 8 between Montesano and Thurston County because of the ongoing construction projects there.

More on beach driving: The do’s and don’ts of beach driving in Washington

Coming off the Montesano cut-off road from U.S. 101 to U.S. 12, you run into a lane reduction. The right lane is blocked. There was a mile-long backup in the left lane from all the drivers who merged way too early. That left the right lane completely open all the way to the merge point. I drove up the right lane until close to the end, and that’s when drivers started veering into my lane to prevent me from going further and then eventually trying to block me from merging in.

Let me be absolutely clear on this. The people veering into my lane and blocking me do not understand how to merge or how zipper merging works. They are doing it wrong.

Let’s revisit the Washington Department of Transportation’s friendly video on how it’s supposed to work.

“To reduce congestion, remember to zipper,” the video announcer said. “Merge late and cooperate. It’s OK to take turns.”

Merging early actually creates unnecessary congestion

“Driver cooperation helps increase the number of vehicles passing through and actually reduces congestion and delays,” the video said.

I have always wondered if better signs would work to help drivers understand the concept. I have seen signs in other states that actually show the traffic merging, like the teeth on a zipper, and have seen smaller cities use similar signs.

And then this week, I went up to Everett to look at the four-month closure of the northbound Snohomish River Bridge on 529.

And to my surprise, the City of Everett put up a series of orange signs spelling out exactly how to properly zipper merge. Check them out above. They read “Use Both Lanes to Merge Point.” “Zipper Merge Ahead.” And finally, “Merge Here Take Turns.” What do you think? Would this better explain the situation?

If they work for the City of Everett, I wonder why they aren’t used by the Washington State Department of Transportation (WSDOT) for construction projects like the ones I hit on the way to the beach.

WSDOT doesn’t use these smaller, static orange signs in its construction zones because the speeds are usually higher in these construction zones, and there are times when there is no backup at all. Pushing drivers to a later merge when traffic is flowing at a higher speed can cause problems too.

“We don’t want drivers to wait until the last minute to merge when traffic is moving at speed. Orange static signs would not be appropriate in this condition. Static orange signs may be appropriate on low-speed roads,” WSDOT wrote me in an email.

More on Washington roads: Designs unveiled for new I-5 bridge between Washington, Oregon

Zipper merging is most appropriate when there is bumper-to-bumper traffic and the speeds are low. Merging at speed should be done when there is a safe gap to do so.

On U.S. 12 and State Route 8, WSDOT uses smart signs that put up variable messages to meet the real-time demand. They do instruct drivers to use both lanes and take turns at the merge point. I just must have missed them on my trips. There were two that were blank as I approached the backups.

The bottom line is this: Merging early causes congestion. Drivers using the open lane are not cutting the line or cheating.

It’s time to figure this out.

Check out more of Chris’ Chokepoints here. You can also follow Chris on X, formerly known as TwitterHead here to follow KIRO Newsradio Traffic’s profile on X.


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Sullivan: Drivers slow to understand zipper merge, would better signs help?