Beware the Zipper Merge

construction zone collision

Authorities said a semi-truck slammed into the rear of another semi that was stopped for the construction backup.

“He tried to stop, but just didn’t have time,” sheriff’s office Sgt. William Hoskins said. The second semi was pushed forward into a third semi.

Merging Lanes Ahead

For some drivers, nothing is more frustrating than merging to a single lane. Traffic becomes much slower and it always seems someone is trying to position themselves to the head of the pack.

The problem? According to traffic experts, most of us merge too early, causing a single lane that may stretch for miles, and slowing things down even more. Most drivers say they are early mergers.

The solution? The late merge, better known as the ‘zipper merge.’  A University of Nebraska study by the Midwest Roadside Safety Facility found that the zipper merge method allows 15 percent more traffic to move forward than early merging. The Minnesota Department of Transportation (MnDOT), an early zipper merge adopter, claims in the case of congestion this method reduces backups by 40 percent on average, since “both lanes approach the merge with equal stakes in maintaining speed.”

zipper merge

The theory of the zipper merge is that a consistent traffic flow should be maintained for as long as possible and traffic should only merge where needed. Highway road signs will indicate the following:

Location Warning
Two miles Merge Two Miles Ahead. Use Both Lanes
One Mile Merge One Mile Ahead. Use both Lanes
At point of merge Merge Here and Take Turns

Do the zipper merge sign






MnDOT created this video on the zipper merge . . .

More states are adopting the zipper merge.

As in any construction zone merge, drivers need to remain vigilant, drive defensively, maintain a safe following distance and a space cushion around their vehicle, slow down and always be ready to stop, if necessary. On a daily basis, there are far too many rear-end, construction zone collisions occurring, or secondary collisions after a primary collision, resulting in mass destruction.

What Not to Do When Merging

Drivers should not act as a traffic cop. Trucks sometimes line up side-by-side to impede the flow of traffic.

A.) Intentionally blocking or impeding traffic is totally illegal.

B.) While illegally blocking traffic, there is the risk of getting rear-ended or side-swiped by someone who is not paying attention. Insurance companies may have the right to reject a claim in these circumstances.

• Don’t expect everyone to do it right. There tends to be a lot of confusion when merging. There is no forewarning as to which lane to be in when doing the zipper merge. When traffic is slow, for safety reasons, motorcycles may “lane split” or drive on the shoulder. Be courteous and drive friendly.

• DO NOT TAKE RIGHT OF WAY. If you lose your turn, someone else will let you in. Right of way can only be granted — never taken.

What to Do When Zipper Merging

• Remain in your lane. Maintain a good following distance and space cushion. Follow the directions of any warning signs.

• When merging, signal intentions, check the mirrors and ease into the lane indicated.

• Treat traffic like a team sport. Play the assist role. Yield to other vehicles when it’s their turn to merge.

Thank you for reading this.








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