Commuting in heavy traffic can be a pain and merging can make it even more stressful – especially when it seems that drivers are playing by different rules.

A lane is closed ahead: Two lanes of vehicles will soon be narrowed to one. Some drivers merge early and get to the correct lane as fast as possible, then wait for traffic to advance. Others don't seem to have a problem zooming ahead and "cutting" in line.

But according to many experts, the driver trying to be polite is probably making traffic worse than the driver who jumped ahead.

William Van Tassel, American Automobile Association Manager of Driver Training Programs, said that AAA recommends using the "zipper" approach to merging.

The zipper method, in which drivers merge late, is based on the idea of a zipper's "teeth." Just as a zipper smoothly comes together, a zipper merge can keep traffic flowing in both lanes by bringing some organization to the merging process, AAA says.

"The zipper merge has shown to keep traffic moving more smoothly, compared to a less structured approach," Van Tassel said.

A zipper merge is recommended because leaving a lane unoccupied as a result of early merging is inefficient. It only makes traffic heavier, proponents say.

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The Colorado Department of Transportation encourages drivers to use the zipper merge tactic. And it can reduce delays up to 40%, it said.

"We all learned in kindergarten not to cut in line, and there are lots of people who think zipper merging is cutting in line,'' Fort Collins traffic engineer Joe Olson told the Coloradoan. "Zipper merging is for the greater good, but people still don't see it that way.'

Some states' drivers are resistant to the more efficient, but seemingly less polite maneuver. According to Wired, Minnesota launched a media blitz to encourage drivers to zipper merge in 2011, with billboards and more.

Drivers in California have had trouble coming to an agreement on whether late merging is acceptable. In 2017, the Sacramento Bee searched for a tie-breaker on what was appropriate merge etiquette in the state, but a highway patrol spokesperson simply told them that drivers should merge cordially and safely.

No matter what, it's important to remember that merging isn't a race.

"When merging, your goal should be to maximize your smooth 'flow' forward through traffic, not to 'beat' other drivers," said Van Tassel.

Follow Morgan Hines on Twitter: @MorganEmHines.