The folks at the Missouri Department of Transportation want you to practice zipper merging.
No, it doesn’t involve the pair of pants you’re wearing, nor does it involve a ladies’ clutch purse. Zipper merging just might be the answer to the angst and impatience you feel as you leave Springfield and head south on U.S. Highway 65 to get home to Ozark on a Friday afternoon.
Then you hit that road construction zone and all that extra traffic from tourists heading to Branson. Signs warn you that the left lane of the highway will end because of construction. Before you risk life and limb cutting in front of and dangerously close to that charter bus full of visitors who can’t wait to see Shoji Tabuchi, MoDOT engineers advise you to think about zipper merging instead.
“Wait to merge, take turns,” is the somewhat rhyming slogan MoDOT wants you to remember about the zipper merge.
“Early merging” is what most of us typically do. If traffic is light, we see the signs for an upcoming lane closure ahead and we merge over as soon as possible. If traffic is light enough, we don’t have to adjust our speed. It’s better to go ahead and get over in anticipation of the lane closure.
“Zipper merging” works best in heavier traffic with slowing and sometimes full-on stopping traffic. Drivers are encouraged to fill both lanes of the highway right up until the point where the lane ends. At that point, the drivers take turns merging their vehicles “every other car” at the point of the lane closure.
When done correctly, the traffic will appear from an aerial view to resemble the two sides of a zipper coming together to hold a jacket or bag closed.
“By using two full lanes of traffic until the merge, you reduce the difference in speed between the two lanes. The length of backups is reduced 40-50 percent. When both lanes continue to move slowly, everyone is equally delayed, which reduces road rage,” MoDOT officials explain in a press release about zipper merging.
MoDOT also made a video entitled “Zipper Merge: Kids, Adults in Cardboard Cars and Taking Turns,” to illustrate zipper merging.
The video starts with a parade of adults wearing vehicles made from cardboard boxes walking along what appears to be a road outside of MoDOT’s headquarters in Jefferson City. There are vehicles of all types, including buses, tractor-trailers, sedans, pickup trucks and sports cars.
Kids as old as 10 and as young as 3 watch as the adults dressed as cars demonstrate different types of merging. First, they watch the adults practice early merging, and walk together very slowly in one lane of traffic.
“They’re moving slow,” one child says.
Next, they watch a simulation of a common sight on U.S. Highway 65, drivers scrambling to be the first vehicle past the merge point, a driver attempting to cut his way into traffic in the adjacent lane, and the people in that lane refusing to allow the vehicle to merge.
“Why aren’t they taking turns?” a child asks.
Finally, the kids watch a demonstration of zipper merging, which the grownups in cardboard cars execute perfectly.
“Now that they’re taking turns, they move a lot faster,” 10-year-old Brooke tells the camera.