The yellow sign with a zipper on the Durham Freeway isn’t a reminder to XYZ (examine your zipper), but an attempt to get drivers to use all lanes while merging.
About a week ago, a succession of signs encouraging drivers to “merge like a zipper” popped up on the stretch of highway where N.C. 147 and Interstate 85 South merge.
When Corkey Payne saw the signs, one of which is just a picture of a zipper, he didn’t really understand.
“I said ‘What in the world?’ ” said Payne, who owns Bull City Radiator & Wrecker Service, which is just off the I-85 exit after the merge.
The signs are an experiment, said Nicole Meister, a spokeswoman for the N.C. Department of Transportation.
The signs are meant to encourage motorists to use all open lanes heading into a merge, with drivers then coming together like the teeth in zipper as they approach the lane closure.
The way most people drive now, most cars line up in the merge lane way before the additional lane closes, which can cause congestion.
“The zipper merge encourage drivers faced with lane closures to work together and take turns where the lanes merge,” a transportation department press release states. “Not only to reduce congestion for all vehicles, but also to improve safety.”
During congested periods, the transportation department encourages driver to be “extra courteous” to other drivers, and understand those in the closing lane “are not simply trying to cut in line in front of driver in the open lane.”
The transportation department is working with N.C. State University to determine if the zipper merge can be successful at certain locations across the state, Meister said. Zipper merge signs have also been installed on N.C. 58 at the Emerald Island bridge.
Congestion doesn’t occur at the Durham merge every day, Meister said, but when it does it is significant.
N.C. State University researchers found that the zipper merge has the potential to reduce backups as much as 50 percent, according to information provided by the transportation department.
N.C. State engineers studied back ups at the Durham spot for a three-week period. They will compare that information to the data they observe with the new signs to determine whether it was effective in changing drivers’ behavior.
Several other states, including Michigan and Minnesota, have implemented the zipper merge and have decreased the length of backups and created safer, smoother driving conditions.
One site in Michigan saw congestion reduced from six miles to three miles, according to information provided by the transportation department.
Keely Godwin said she has noticed a difference.
Godwin, who frequently travels the route, said when other drivers avoid the closing lane way before it ends it creates a “big tangle,” while there are thousands of yards of an empty lane.
“But since they put the signs up, I have noticed people are little bit better at using all the lanes,” she said. “Certainly the merging aspect of it has become a lot better. “