Can I move past traffic and get over at the end? Here’s why Kansas DOT uses zipper merges
Waiting in backed up traffic in a construction zone can arguably be one of the most frustrating parts of driving. But one way of merging out of a closed lane in construction, called zipper merges, can actually reduce the risk of backed up traffic.
The Kansas Department of Transportation says zipper merges happen when “drivers use both lanes of traffic up until reaching the defined merge area, where they then alternate turns in ‘zipper’ fashion into the open lane.” They are usually used to control traffic at construction zones.
The agency refers the concept in a formal term, late-lane merging.
So, in short, zipper merges are when both lanes are used fully until the the closed lane ends, when drivers alternate merging into the fully open lane, creating a “zipper” effect. In lighter traffic, zipper merges do little to fix the back up of traffic, but in heavier traffic it can reduce traffic substantially, experts contend.
The Montana Department of Transportation found zipper merges can actually reduce backed up traffic up to 40%.
Zipper merges in Kansas
Kansas was one of the first states in the U.S. to embrace the concept of zipper merging, along with Missouri and Washington, according to reporting from The Hill.
KDOT first introduced the concept in a 2016 U.S. 69 project.
“When drivers see the ‘lane closed ahead’ sign and traffic backing up, drivers should stay in their current lane up to the point of merge and then take turns with the other drivers to safely and smoothly merge into the remaining open lane,” a KDOT article about the 2016 project said.
In past years, the agency has used the zipper merges for particular projects. A social media post on X, formerly Twitter, in 2016 said zipper merges should be used when construction signs indicate such. For example, “use both lanes” and “merge ahead 2 miles.”
In an email to The Wichita Eagle, a KDOT spokesperson said zipper merges or late-lane merges are not very common in Kansas.
“Static late lane merges as marked by signage are not all that common. When used, it’s mostly in urban areas where traffic counts are higher,” wrote Steve Hale, director of communications for KDOT.
Hale also said late-lane merges are only used when two lanes are combined into one.
“More than two lanes and the late lane merge does not come into play,” he said.
Safety tips for changing lanes in Kansas
No matter if you’re using the zipper merge or just changing lanes regularly, it’s important to take safety precautions.
Here are some tips for safely changing lanes while behind the wheel, from Direct Auto Insurance:
- Turn on your turn signal
- Check both side mirrors and your rearview mirror
- Look over your shoulder in case of blind spots
You shouldn’t brake or slow down when changing lanes, nor should you drift while looking over your shoulder. Instead, after checking your blind spots, look ahead if clear and make the lane change.
You also shouldn’t take a long time doing all the steps, as that can cause confusion with other drivers, Direct Auto notes.
