The Minnesota Department of Transportation first introduced the “zipper merge” in the early 2000s. Yet a decade later, it’s still trying to educate motorists on the proper and polite way to merge in construction zones.

Despite its 10-year presence on state roads, more than 60 percent of the people who participate in online forums sponsored by the agency to talk about transportation issues said they were unaware the zipper merge is an acceptable driving technique that is included in the latest edition of the Minnesota Driver’s Manual.

In work zones where the zipper merge is employed, drivers are instructed to use both lanes until they reach a designated merge point. Then motorists are to take turns to safely and smoothly flow into the remaining lane.

It has been a tough sell, admits Ken Johnson, MnDOT’s state work zone engineer. Many drivers tend to merge when they encounter a sign announcing a lane closing, even if it’s well up the road. Then they get frustrated as other motorists zip by them while they wait in traffic.

“A lane can be legally used up to the point where it is closed,” Johnson said. “We try to make it understood that it is law to use both lanes and get the benefit of a reduced queue length” and that both lanes are “equally disadvantaged.”

During April and continuing through July, MnDOT is placing public-service announcements on radio and TV stations, news websites and highway billboards. The agency also has posted information on its Facebook page and created video tutorials that play on YouTube and

Since zipper merging is “somewhat unique to Minnesota,” Johnson surmises that might be one reason drivers are not overly familiar with it. But mostly, it’s a challenge to change the mind-set of drivers who think others are “cheating,” he said.

The zipper merge is aimed at curbing such behaviors as queue jumping, in which drivers move from the slower lane into the faster lane and then back to the slow lane closer to the merge point. It’s also aimed at preventing motorists who are in the faster lane from stopping abruptly and forcing their way into traffic. Some play “self-appointed trooper” and straddle the lanes so others can’t pass by. Motorists who impede traffic can be ticketed, said Lt. Eric Roeske of the State Patrol.

If followed properly, the zipper merge reduces backups, maintains uniform speeds in both lanes and creates a sense of fairness, said Sue Groth, director of the Office of Traffic Safety and Technology.

“We know that the majority of people understand that it is legal for them to use both lanes, but that they don’t because they don’t want to be the person that is perceived as barging in,” she said. “That is exactly why we want to educate people about the use of the zipper merge in construction projects when it is congested. We are hoping that by telling them it is OK — and in fact, we want them to do it because it helps reduce backups — they will be more willing to participate.”

In the metro area, the zipper merge will be used on Hwy. 169 at the Bloomington Ferry Bridge and between Crosstown and Hwy. 7 and I-694 and Hwy. 55.

It will be used on I-35 and I-35E through Lakeville and Eagan, and on I-494 between Hwy. 100 and Cedar Avenue.

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