Zipper merge: Don’t be afraid to stay in the clear open lane until last minute

May 27, 2014, 5:56 AM | Updated: 5:56 am
Trying to be polite and merge as early as possible could be really slowing us all down. (AP Photo/D...
Trying to be polite and merge as early as possible could be really slowing us all down. (AP Photo/David J. Phillip)
(AP Photo/David J. Phillip)

We’ve all been there, sitting in traffic as two lanes merge into one. We politely merge as early as possible, now we’re sitting in the clogged lane and as we watch somebody in the other lane drive all the way to where the lanes narrow, forcing a merge at the last second, and we think, that guy is a jerk. It turns out, that is the smart guy, and we’re the jerks.

There is a traffic phenomenon called “zipper merging,” which can drastically reduce traffic backups.

Maan Sidhu, freeway operations engineer for the Washington State Department of Transportation, told Seattle’s Morning News on KIRO Radio how it works.

Sidhu says taking advantage of both lanes, the open one and the one jammed up, and then merging in at the last minute, can reduce traffic and reduce risk of collisions.

“Really, if the drivers cooperate and they’re looking out for their fellow drivers and they’re alternating back and forth, we can have these sort of reductions.”

But KIRO Radio’s Dave Ross argues there’s a real psychological barrier to jumping into the open lane and swooping past everyone waiting. “You’ve got to convince people it’s OK,” he says.

Sidhu says they’re making a start by talking about it on the radio, and he’s glad they’re starting the process of raising awareness.

“It really does help through these construction zones, especially where it’s heavy and slow,” he says.

When the traffic is free flowing and there’s no backup, he says feel free to merge whenever, “but when it’s heavy and slow traffic, let’s do zipper merge,” says Sidhu.

Let’s all work together here. Pass this along to all your friends who might be handling the zipper merge incorrectly.’s Jamie Skorheim contributed to this report.

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Zipper merge: Don’t be afraid to stay in the clear open lane until last minute