MONTICELLO, Minnesota — Building roads is expensive, but what if you could build a better road? A road that lasts longer and is less harmful to the environment?

You may not realize it, but it’s what MnDOT researchers have been working on for decades now. Every day, thousands of drivers head north on I-94 near Monticello, unaware that every mile they drive is being surveyed.

“We’re trying to make our roads last longer,” says MnRoad coordinator Glenn Engstrom.

Engstrom and his fellow researchers have worked for nearly 30 years to build a better road at their state-of-the-art MnRoad facility. The facility was created to test new ways of building and maintaining roads. Research began around 1994 and since then MnDOT researchers and engineers have tested hundreds of new ideas.

“There really is nothing like it in the world,” says Engstrom.

Samples of road and soil materials are stored so researchers around the world can study them and better understand what worked well in Minnesota’s four-season climate and what didn’t.

“These are some of the original samples from the construction and opening of MnRoad in 1994,” Engstrom says, pointing to road samples in the facility’s storage shed. “Each of them has a different mix.”

Most of the tests don’t work completely, but Engstrom says that’s the point of these experiments. “We like chess to a certain extent, so we can see what happened, how it failed,” he shares.

Every once in a while, road warriors come across a game-changing idea like creating weight restrictions in the spring when the road is still thawing.

“We’ve done calculations that show we’re saving about $14 million a year in road damage from these weight restrictions,” Engstrom said.

MnDOT researchers have also discovered new ways to recycle old road materials, such as grinding them up and mixing them with fresh materials to build new roads. In other situations, crews can salvage a road’s base layer and build on top of it, saving thousands of tons of concrete and millions of dollars in taxpayer dollars.

Thanks to MnRoad’s decades of research, modern highways and highways are now cheaper, thinner and, in many cases… stronger.

“Generally our roads are thinner and they perform at least like our previous and generally better designs,” says Engstrom.

Ideas and concepts are tested on two different MnROAD tracks. One is a “low volume loop” intended to mimic city and county roads. To simulate the wear and tear that occurs on a typical city or county road, the research team will load a tractor-trailer with metal weights so that it weighs exactly 80,000 pounds.

“That’s the weight limit in Minnesota,” says Engstrom.

Once the trailer is loaded, a full-time driver will drive this trailer around the low-volume loop eight hours a day, five days a week. Round and round, between 60 and 70 rounds a day.

The second MnRoad test track is used to simulate the conditions you typically see on highways and freeways. The track is immediately laid out on the I-94 between Albertville and Monticello.

Drivers heading north through this area will notice that the highway splits into two different sections. A section is mostly a conventional road that motorists in Minnesota drive every day. The other section is divided into several smaller sections that each contain a different mixture of road materials.

“Each section is just slightly different depending on the types of mixes we test,” says Engstrom.

MnRoad’s work team installed its first batch of hardware experiments on I-94 in 1994. Engstrom says the team studied those samples, then tore them up in 2008 to make way for a new batch of experiences.

These experimental sections established in 2008 were also recently removed, and now the team is working on a third batch of test samples which should be installed and ready for traffic by the end of September 2022 “We can really do a lot of neat stuff here,” Engstrom says. “We can do roads that we would never do under ordinary circumstances. We can test things that no one else gets to test.”

Engstrom feels many of the best ideas are still taking shape, such as mixing different types of fibers and recycled materials to make the road stronger, longer and more environmentally friendly.

A company the MnROAD team is working with has the idea of ​​mixing recycled pop bottles with more traditional road building materials. “They say they can mix 150,000 soft drink bottles in a mile that they could recycle into product. So that’s really exciting,” says Engstrom.

The hope is that the next big breakthrough could be in one of those 35 new sections laid on I-94, but it will probably take 10 or 15 years to find out.

“We’re only scratching the surface here,” says Engstrom. “I think the future is extremely bright.

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