Should you Late Merge? aka Zipper Merge

tldr; Yes you should as it can reduce wait times by up to 40%.

You know the scenario: You are driving down a highway with two or more lanes. In the distance you see a construction sign warning that one or more lanes are closed up ahead. For some people this is a signal that it is time to move into the lane that will remain open and wait your turn. For other people this is a signal to speed up and get to the merge point quickly to get ahead of everyone.

What is the correct option? Be courteous or be a jerk?

Research shows that using the entire open road and then merging at the lane closure, when traffic is congested, will result in the shortest wait time possible for everyone. The issue is that we do not educate drivers in the US about proper merge techniques. So drivers are left to their own devices for figuring this out. From that we get the two generalizations: be polite and wait, or be aggressive and pass everyone.

Instead we should drive cautiously to the merge point and then alternating merging together one car at a time:

If roads are clear enough that everyone is already driving close to the speed limit, zipper merging isn’t as effective, but in the case of congestion, Johnson said that this method reduces backups by a whopping 40 percent on average, since both lanes approach the merge with equal stake in maintaining speed. “When the queue backup is reduced, the access points behind a work zone, like signals or ways to get on and off the freeway, those aren’t blocked,” Johnson pointed out. “People have a better opportunity to get off or on the system at that point.

The beauty of zipper merging, or why you should drive ruder

So go on use the entire roadway and help everyone get through the bottleneck faster. Just do it cautiously and keep an eye out for people pulling in front of you.


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