Road Rage, ‘Zipper Merging’ and a Stress-Free Path Through Traffic

You are approaching a construction site and a sign indicates that the left lane ends a few miles further. Traffic is heavy, but you see an opening and switch to the right lane. As you move forward, the drivers zoom by on your left. Miles ahead you will eventually reach the merge point and the drivers in the left lane make their move. Your pulse is quickening. You hold onto the car in front of you and don’t let anyone in. Are you right or are you lucky that nothing escalates?

Merging is easy when there is little traffic. In the case of moderate to heavy traffic, the early crossing fails when opening for the first time, where using both lanes for as long as possible can achieve greater efficiency. Easy right? Not at all.

Traffic experts largely agree that the best way to combine two busy lanes is a technique known as a zipper merge. Drivers use both lanes until just before the end, then they merge like the teeth of a zipper: one from this side, one from that side, hopefully with minimal slowing down.

When this expertly recognized pattern is put to the test on highways, the results are downright mixed. However, more and more states are promoting zipper merging and driver education – or even making it law.

Driving a car is a complex task that requires concentration. When things work to our advantage along the way – traffic lights, road conditions, weather – everything is fine. If they get in our way, stress is the likely consequence. And when another driver is the source of that stress, it can turn into anger.

We call it street rage, and it’s a serious problem that leads to accidents and even violence. It can come from something simple, such as someone driving us up, braking too hard, honking the horn, flashing a light to overtake or neglecting a turn signal. But few things on the street seem as angry as the amalgamation described above. According to a study by the Texas Transportation Institute, merging difficulties are responsible for more than half of the top drivers of stress related to automobiles.

I posted a description of the zipper on a Facebook auto enthusiast group, along with a video illustrating the technique, and asked for public comments. Many said they would switch to the through lane as soon as possible and were annoyed when others stormed along until the last moment. Some vowed that they would turn anyone who took this route off the road. One respondent said the best anti-zipper argument in the United States was that too many dangerous fools were carrying pistols and willing to use them.

Traffic experts are passionate about zippers being merged and have statistics to back it up. The Minnesota Department of Transportation names four advantages: it reduces speed differences between the two lanes, cuts traffic jams by up to 40 percent, reduces traffic jams at intersections and creates the feeling that the lanes are moving more evenly. The Texas Transportation Institute found that a zipper merge strategy delayed the congestion at the merge point by about 14 minutes and shortened the maximum vehicle line by 1,800 feet.

Some states have zipped the law. In 2020, Illinois ordered that its manual on the rules of the road to include zipper pulling together. Violations that prevent others from merging will result in a fine.

“The law specifically states that every driver must reduce speed and / or position in order for a person to actually drive in,” said Sgt. Delila Garcia of the Illinois State Police.

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July 9, 2021, 6:58 p.m. ET

North Carolina House passed bill that would require zippers to be merged when lanes merged into one. The bill, which has yet to be passed by the Senate, also provides for driver’s licenses and driver training manuals to include the zipper.

Rep. Brian Turner, a Democrat, supported the law. He commutes more than 200 miles from Asheville to Raleigh each week and spends a lot of time on the North Carolina highways.

“Anyone who goes a long distance to get to Raleigh knows that the most frustrating thing about the road is someone driving slowly in the left lane,” Turner told a House committee, as in The Citizen-Times of Asheville quoted. “The second most frustrating thing is when we go from two lanes to one and all drive back in one lane.”

When the bill goes into effect, it can be difficult to enforce. But even without penalties, it could at least encourage drivers to use the zipper.

Despite all these efforts, the behavior is still perceived by many as rude. They feel like motorists continuing in the final lane cut in front of them and many angrily refuse to give way, shake a fist or even swing a gun. There is potential for worse. According to the American Psychological Association, 30 kills are linked to road anger annually.

Traffic signs telling drivers to use both lanes up to the junction can help drivers behave better. The Colorado Department of Transportation determined that the only way to properly break in drivers at construction sites was to have a series of signs posted both well in front of the work area and at the intersection. One read, “Use both tracks to merge point.” Other states have also started adding signs.

Lance Aldrich, a Michigan writer who has railed against those who refuse to queue early, said, “Americans are fierce protection of their property rights. They see someone sneaking in at the last moment, as an intruder trying to steal something that rightfully belongs to them. Perhaps if the zipper method were taught from an early age and shown to serve the common good, it would work. But otherwise don’t think about squeezing yourself in in front of me. “