Ask a Trooper: What's the proper way to zipper merge?
Send your questions concerning traffic related laws or issues in Minnesota to firstname.lastname@example.org or Sgt. Neil Dickenson – Minnesota State Patrol at 1131 Mesaba Ave., Duluth, MN 55811.
Q: What is the proper technique when there is a zipper lane? For example, coming off of (Interstate) 35 onto London Road, there are two lanes, but everyone merges over to the left lane immediately upon getting onto London Road. I learned to drive, and spent most of my driving years in Washington state, and we learned that when there are two lanes, use both of them until they merge, and merge every other vehicle. Is this true in Minnesota also?
A: According to the Minnesota Department of Transportation, a zipper merge is when a lane is closed in a construction zone. A zipper merge occurs when motorists use both lanes of traffic until reaching the defined merge area, and then alternate in "zipper" fashion into the open lane. The merge that you are talking about does not have an active construction zone, but a merge is required, and so the same rules would apply.
Motorists should use both lanes of traffic in a construction area or merge zone. Traffic should not merge together until reaching the designated merge area. At that time, vehicles should alternate in a “zipper” fashion into the open lane.
Some drivers slow too quickly and move over to the lane that will continue through the construction area. This driving behavior can lead to unexpected and dangerous lane switching, serious crashes and road rage.
Some motorists will intentionally drive slow or block the lane that is closing because they believe drivers are trying to “beat” the traffic. This is not only dangerous and can lead to a crash or road rage, but it’s also illegal. Remember, the driver using the open lane is following the proper way to merge.
It is suggested that when you see the “lane closed ahead” sign and traffic backing up, stay in your current lane up to the point of merging. At that point, take turns with other drivers to safely and smoothly ease into the remaining lane. When traffic is heavy and slow, it is much safer for motorists to remain in their current lane until the point where traffic can orderly take turns merging.
Studies show that the “zipper merge” works the best to keep traffic flowing, especially when there is a lot of traffic.