Can I move past traffic and get over at the end? What KY law says about a zipper merge
One of the most frustrating aspects of driving in traffic is getting cut off at a merge point, when two lanes converge into one. However, those drivers merging at the last moment might be smarter than you think.
This merge strategy, known informally as a “zipper merge,” has become increasingly topical across the country as construction projects persist on a seemingly never-ending schedule. Its use has been recommended and studied in several states, but is it the right strategy for Kentucky motorists?
Here’s what you need to know about zipper merges in the Bluegrass State.
How do zipper merges work?
If you’re a longtime driver, executing a zipper merge might seem a bit strange at first.
Broadly the concept is simple. A zipper merge — also called a “late merge” — can occur when two slow-moving lanes converge into one, commonly seen in active construction zones along highways and turnpikes. Motorists following a zipper merge are encouraged to use both lanes of traffic until reaching the merge point, where drivers then alternate into the continuing lane in a zipper-like fashion.
Zipper merges are practically the opposite of the “early merge,” or the more common practice by which drivers move as soon as possible into the lane that will continue through a construction zone. Early merges, while perhaps more convenient at face value, can lead to unexpected lane switches that may contribute to crashes, road rage and other undesired driving outcomes, researchers say.
A Montana Department of Transportation study found zipper merges can reduce the overall length of traffic backup by as much as 40%. MnDOT recently led campaigns to encourage and promote the use of zipper merges in slow-moving traffic, though the technique is not required by law.
A 2018 study completed by the University of Kentucky’s Kentucky Transportation Center, in cooperation with the Kentucky Transportation Cabinet, found promising results for zipper merges following a few early trials. In its report, the research team suggested agencies should focus on identifying additional operational features for an ideal zipper merge (such as speed limits and the number of lanes), all while helping the public understand the technique more properly.
“Public awareness is one of the most important aspects of implementing a zipper merge,” the Kentucky Transportation Center team wrote in the report’s conclusion. “This includes the use of clear signage and public education campaigns. All drivers (including truck drivers) must know how a zipper merge operates and understand that it is utilized to benefit them.”
Zipper merges require the cooperation of many drivers on the road. In a 2019 TED Talk presentation, California Department of Transportation engineer Oliver Asis encouraged zipper merge use and said traffic should reduce as more and more drivers do their part.
“You have to collaborate and work together with your fellow drivers for [traffic to reduce]. We all know sometimes in the real world this doesn’t happen,” Asis said. “But the next time you find yourself in a situation in which you have to merge, consider doing the zipper merge. It only helps reduce traffic, reduce your frustration levels and, on top of that, get to your destination more quickly.”
Are zipper merges required by law in Kentucky?
In short, no.
Zipper merges are not required by law throughout the commonwealth, but Kentucky researchers have explored the technique and found generally promising results. Regardless, drivers will not directly face penalties for choosing to merge into a single lane early, though doing so may result in more traffic congestion overall.
The technique’s use is directly recommended in a few U.S. states, including Arizona, Washington, Missouri, Kansas and North Carolina, according to reporting by The Hill, which also notes zipper merges are more commonly seen in Europe.
Driving safely in Kentucky
The Kentucky Transportation Cabinet’s Office of Highway Safety maintains an online fact sheet offering all-purpose tips and advice for drivers throughout the commonwealth.
Broadly, drivers on Kentucky highways should be mindful of vehicles and obstacles around them by looking ahead, keeping a “space cushion” between other cars, signaling their intentions, checking their mirrors and using headlights when necessary, the guide reads. Be sure to take adequate precautions against inclement weather and stay vigilant when determining the right-of-way when turning at an intersection or merging lanes.
Drivers in Kentucky should be mindful of their mirrors. The Kentucky Office of Highway Safety encourages the following steps for mirror adjustments:
- On the driver’s side, turn your head to the left until it rests against the window and adjust the mirror to barely see the side of the vehicle.
- On the passenger’s side, tilt your head to the right until it is under the rear-view mirror and adjust the mirror to barely see the side of the vehicle.
- Frame your rear window with the rear-view mirror.
Proper seating position is also key. The following guidelines are recommended, according to the Kentucky Office of Highway Safety’s manual:
- Your shoulders should be even with the top of your steering wheel.
- Your chest should be no closer than 12 inches to the steering wheel airbag.
- The steering wheel airbag section should be pointed at your chest.
- The top of the head restraint should be at least as high as the top of your head.
For more safety information from Kentucky officials, visit highwaysafety.ky.gov.
This story was reported in response to reader questions and comments from our Know Your Kentucky project. If you have a question about Kentucky, we’d like to hear from you. Fill out the form below or email ask@herald-leader.com.
%202.JPG)