Do the Zipper Merge

 Earlier this week I am driving in the left lane of a two-lane highway that is about to merge into one lane less than a mile ahead.  Other drivers have moved to the right lane early and are at a standstill.  I am still moving rather briskly in the left lane as I head down to the final merge point.  I am now getting a few dirty looks, a few shaking heads, and one obscene gesture. Have you seen this as well?  Would you also be frustrated with a driver like me going past you to get to the final merge point?  Why can’t I be “Minnesota Nice” and just merge into your lane – the proper lane – earlier?  Am I somehow cheating?  Why am I being so rude?

Actually, I am being a zipper merger and not an early merger.  And believe it or not – The Minnesota Department of Transportation (MnDOT) wants you to be a zipper merger as well.   They state that most Minnesota motorists start to merge as soon as they see warning signs and learn which lane ahead is closed or closing.  This driving behavior, called “early merge” can lead to dangerous lane switching, inconsistent driving speeds that cause crashes, long back-ups that block interchanges, and road rage.  Research shows that these dangers actually decrease and traffic moves more smoothly when motorists use both lanes until reaching the defined merge area and then alternate in “zipper” fashion into the open lane.

MnDOT states that the zipper merge benefits drivers by:

  • Reducing differences in speeds between two lanes
  • Reducing the overall length of traffic backup (by as much as 40 percent)
  • Reducing congestion on freeway interchanges
  • Creating a sense of fairness and equity that all lanes are moving at the same rate
  • Reducing incidents of road rage

MnDOT has started a campaign this summer promoting the use of zipper merging, especially in construction zones.   Check out the website with associated video at –

Drivers use both lanes with zipper merge