By JOHN BOYLE, Asheville Watchdog
We should all get in touch with the zipper.
The zipper merge, that is! Get your mind out of the gutter, and onto the interstate.
Not surprisingly, I apparently have been a bit of a dolt for not better educating you good readers about this marvelous technique that reduces wait times when lanes have to merge because of construction, allows traffic to flow more smoothly, makes your teeth and bones stronger, and allows people to save more money for retirement.
OK, I made up those last two, but zipper merging really is important for all of us to adopt. And it works.
First of all, you may be asking, “What is a ‘zipper merge,’ doltboy?” Actually, I know you’re asking because of my email inbox.
I heard from several folks after two recent columns I wrote – an Answer Man column last month in which a reader complained about poor signage on I-40 warning about impending merges in the Pigeon River Gorge, and another column in August about crashes on I-26 in the construction zone.
Both readers told me I missed a prime opportunity to educate people about zipper merging, which means essentially traveling as far as possible in the lane that will close, and then alternating merges with the other lane.
This is where the term “zipper” comes from — it mimics the teeth of a zipper, which also have to take turns merging. While it’s logical, the technique can inspire great ire.
“People in this area seem to think that merging at the point of lane closure is a crime,” one reader told me after that I-26 column. “And yet my AI tells me that, ‘In North Carolina, zipper merging is not a mandatory traffic law, but it is encouraged and promoted by the N.C. Department of Transportation as a way to improve traffic flow in merging situations.’”
Indeed it is.
David Uchiyama, NCDOT’s spokesperson for western North Carolina, said the department is using zipper merging, supported by signage encouraging motorists––– to “Take turns” merging, in Haywood County on U.S. 23/74, on Interstate 40 in Canton, and on I-40 in the Pigeon River Gorge for pre-Helene bridge replacements. And you’ll see it on I-40 through the gorge for storm reconstruction.
“The whole idea behind the zipper merge is that it reduces the length of queue lanes,” Uchiyama said. “The idea works if everybody plays ball.”
That’s the key here — we all have to cooperate and not get furious that someone seems to be flying up the open lane at the last minute and cutting in front of us.
Sometimes that guy is me.
I have personally adopted the zipper merge, which maybe I sometimes employ a little too enthusiastically. That’s because I do it just about every morning while getting on I-26 from Airport Road through the diverging diamond intersection, mainly because everyone lines up in the left lane way before the bridge, and if you get behind them you don’t even make the light.
So I get the middle lane and gun it through the curvy part, then squeeze in front of someone in the left lane. Honestly, there’s almost always plenty of room.
OK, on a couple of occasions I’ve generated some indignant horn honking and creative hand gestures, but that’s been rare. It usually works really well.
Checking out the I-40 zipper merge
I definitely was not looking for confrontation when Asheville Watchdog photographer, Starr Sariego, and I headed west Thursday afternoon on I-40 to experience that mega-merge in the Pigeon River Gorge ourselves.
Honestly, we were hoping for a little salty behavior from somebody blaming us for cutting in front of them, but it was a remarkably well-behaved group of motorists. Mostly semi trucks, the travelers heading west through the winding gorge stayed in both lanes until right before the merge, encouraged by the electronic signs on the right side of the road that read, “Take Turns,” and “Merge Here.”
We did come to a full stop a couple of times, and traffic was inching forward, but no one honked, screamed at us or otherwise demonstrated zipper merge dyspepsia.
It was really all quite civil, and kind of boring, honestly. But I will get a really nice mileage reimbursement check for my trouble.
Now, I know this show of civility is decidedly not the case in some places. Having logged a lot of miles on I-40 throughout North Carolina over the years, and I-81 through Virginia, I can tell you that folks often get very perturbed when motorists engage the zipper.
The zipper merge, I mean! Probably on that other technique, too, but let’s not go there…
I think the resistance to zipper merging may in part just be a Southern courtesy thing. It seems rude to seemingly not wait your turn in line and then appear to cut in front of those who have been waiting patiently.
As AAA noted in this November 2024 article, “A 2013 study conducted in Minnesota found that the zipper merge can reduce traffic backup lengths by up to 40 percent, alleviate congestion, promote fairness by having all drivers move at a consistent speed, and decrease road rage.”
The North Carolina Department of Transportation states on its “Dynamic Zipper Merge” page that it introduced new technology in 2019 “that has reduced backups in work zones where two lanes of traffic merge into one lane.” The technology “also has improved safety by warning drivers of any traffic slowdowns or stops as they approach the work zone.”
The system relies on a series of speed sensors set up on the side of the interstate for several miles before drivers must merge.
“The sensors gather data about traffic congestion and then feed the data to message boards that change the signs that drivers see based on the traffic patterns approaching the work zone,” the page notes. “In addition, the department’s Statewide Transportation Operations Center also monitors the zipper merge system.”
Messages may say, “Slowed Traffic Is A Mile Ahead,” or “Traffic Has Stopped 2 Miles Ahead.” Sometimes, when traffic has slowed or stopped, the boards will say, “Use Both Lanes/To Merge Point.” As you enter the work zones, you’ll start seeing those signs that say, “Merge Here/Take Turns.”
“The innovative merge system reduces the confusion between drivers who think they should merge early versus those who want to use the open lanes for as long as possible,” the NCDOT says.
The state says where these systems were deployed, they “dramatically reduced traffic backups.”
NCDOT also noted that this system doesn’t work for every work zone.
“Because of the complexity of setting up the sensors, the system functions best for highways with travel lane reductions that will last for several months and cause significant delays,” NCDOT says.
I can tell you it worked like a charm in the Pigeon River Gorge. Maybe drivers are getting used to it. Or maybe they were just out of ammo.
Everybody was calm and polite, and the merge worked really well. Lesson learned: Adopt the zipper merge, folks.
We’ll all be happier in the long run.
Asheville Watchdog welcomes thoughtful reader comments about this story, which has been republished on our Facebook page. Please submit your comments there.
Asheville Watchdog is a nonprofit news team producing stories that matter to Asheville and Buncombe County. John Boyle has been covering Asheville and surrounding communities since the 20th century. You can reach him at (828) 337-0941, or via email at [email protected]. To show your support for this vital public service go to avlwatchdog.org/support-our-publication/.
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Asheville Watchdog is a nonprofit news team producing stories that matter to Asheville and Buncombe County. Sally Kestin is a Pulitzer Prize-winning investigative reporter. Email [email protected]. To show your support for this vital public service go to avlwatchdog.org/donate.
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Photo credit: iStock
