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Drivers Who Merge At The Last Second Are Actually Being More Efficient


You had a long day at work, the boss was constantly on your case, and to make matters worse, you had to stay an extra two hours to finish up. So you couldn’t be more excited to get in your car and head home.

You turn on the radio to your favorite music station, traffic is flowing nicely and you’ll be home in no time. But then you see a sign that says “lane closed ahead.” You know what that means, traffic is about to come to a halt.

The lane you are currently in is the one that will be closed off. So you immediately switch lanes, thinking that you’re being courteous to the other drivers, but according to experts, you’re actually slowing traffic down even more.

At first, you might think that people who wait until the last second to merge are portraying bad driving etiquette, but transportation departments in various states are encouraging that same move that is upsetting you.


The move that upsets you every time you witness it is called the “late merge,” or the “zipper merge.” It is when drivers who are in a lane that will eventually be closed continue to stay in that lane until they’re forced to merge.

According to Tom Vanderbilt, who is the author of the book Traffic: Why We Drive The Way We Do (and What It Says About Us), the merging late and the purposed symbol you see on the road does not represent greed but it actually improves the commute for the rest of the drivers.


This is not a new system that has been implemented; Colorado actually started the “late merge” about 10 years ago. They would post signs 2 miles from the point where the lane would end. The first sign said, “Use both of the lanes during congestion.”

The second sign would say “Use both lanes to the merge point.” The final sign would be in the closing lane and it read “Take turns. Merge Here.” You’re probably thinking that people who are in a rush would never obey a traffic sign; most people don’t even obey stop signs.

But the results were actually positive according to K.C. Matthews, who is a traffic specification and standards engineer at the Colorado Department of Transportation. He mentioned that they saw a 15 percent increase in cars that were moving through work zones that had closed lanes, and a 50 percent decrease in the length of the traffic line. That’s what I call efficiency!


Although Colorado saw a dramatic decrease in traffic lengths in work zones, Minnesota did not experience the same results. When the Minnesota Department of Transportation tried to implement the “zipper merge,” officials noticed that people who were in the opposite lane of the merging lane would try and keep up with the car so they could not merge.  The result was a lot of confusion and an increase in congestion. Vanderbilt believes that some people will never change their ways and take it upon themselves to monitor the traffic on how they see fit.


Mr. Matthews mentioned an incident where a Federal Highway Administration official was using the zipper merge lane in Colorado. She stayed in the lane until the very end only to watch another driver throw a burrito at her car. Apparently, the other driver was not impressed with her trying to merge in at the last second. This system will not please everyone, but the statistics and results show that it does improve the traffic flow and traffic line length.



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