Weather Forecast


Ask a trooper: Questions answered about Zipper Merge

Question: Could you explain the Zipper Merge for merging into construction zones in Minnesota? Is it law or just a rule of thumb? The MNDOT website explains some of this, but leaves out some information. Also, I have tried using the Zipper Merge many times. It seems that hardly anyone else on the road knows about it. While doing it, I seem to irritate many other drivers that have merged into the open lane way before the actual merge, even to the point of being blocked from proceeding in the lane that is about to close. If another driver intentionally blocks a lane, isn’t that impeding traffic? What are the fines for impeding traffic?

Answer: The “zipper merge” is a Department of Transportation idea.  It is not necessarily law, but it is “within” the applicable laws for that situation and it is more than just a “rule of thumb”.  

It is what we are teaching drivers in all class formats i.e.: driver education, defensive driving, etc. This came about several years ago and is getting a lot more attention as years of education and experience come to fruition.  More and more people are finding out about it all the time and it will get better as time goes on.  Hopefully this will help, especially with road construction season beginning.

As an example, if you are driving in the right lane on a four lane highway and you see a “left lane closed ahead” sign, be prepared to allow those vehicle in the left lane to come over into the right lane.  Keep in mind that the left lane is open until it is actually closed.  That means vehicles can legally stay in that left lane until they reach the spot where there are barrels, barricades and usually a “merge here” type of sign.  Then, the left and right lane vehicle drivers should take turns getting through that merge spot, in a “zipper” type format.  This is what we all need to do to prevent road rage and to make traffic flow smoother even if you don’t agree with it.

Some people have argued that it slows down traffic more than just letting everyone fend for themselves and that we should make everyone get into the right lane sooner (in that example).  Studies show that the “zipper merge” works the best to keep traffic flowing, especially when there is a lot of traffic.  The “zipper merge” also helps prevent road rage from drivers who intentionally go slow in the lane that is closing, and blocking other drivers from passing or getting through.  That is against the law. 

Lane blocking or impeding traffic fines are approximately $139.00 and the offense goes on your driving record. We are watching out for lane blockers in all situations. If you have any questions concerning traffic related laws or issues in Minnesota send your questions to Trp. Jesse Grabow – Minnesota State Patrol at 1000 Highway 10 West, Detroit Lakes, MN 56501-2205.  (You can follow him on Twitter @MSPPIO_NW or reach him at,