Interstate 70 commuters prepare: the Mile High Shift is coming.

It’s a key milestone in the $1.2 billion Central 70 project, when westbound traffic is diverted 30 feet below ground to new lanes between Brighton and Colorado boulevards.

The shift marks a significant step in the overall Colorado Department of Transportation project, which consists of rebuilding a 10-mile stretch of I-70 that extends between Brighton Boulevard and Chambers Road. Beginning in 2018, the project has so far involved constructing the future westbound lanes, a drainage system and the first half of the underpass.

By the end of 2022, CDOT and Kiewit Corporation aim to finish the traffic configuration, with the next biggest steps being the construction of the eastbound lanes and the demolition of the 57-year-old viaduct, which was declared structurally deficient and functionally obsolete in 2008.

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Project director Bob Hays said he hopes that the traffic transition from the current viaduct to the new westbound lanes will be an easy adjustment for drivers.

“We want them to seamlessly flow through this lowered section, and our hope is that the learning curve is very quick, and ultimately traffic is able to flow through this lowered section in a safe manner,” Hays said during a media tour of the site on Tuesday.

To accommodate the shift, I-70 will close in both directions from Washington Street to Interstate 270, from 10 p.m. May 21 to 5 a.m. May 24. All six lanes of I-70 traffic will be moved off of the existing viaduct onto what will be the future westbound lanes of I-70.

CDOT recommends that westbound travelers use I-270 to westbound Interstate 76, then go south onto I-25 before exiting onto westbound I-70. Those traveling eastbound should go north on I-25, take eastbound I-76 and continue east on I-270 before getting back onto I-70 East.

Additional upcoming street closures include the Colorado Boulevard on-ramp to westbound I-70, which will close from 8 p.m. May 19 until 5 a.m. May 24. The eastbound I-70 off-ramp to Steele/Vasquez will be closed for eight months, starting at 5 a.m. May 24.

One of the newest features that drivers can expect to see is an underpass with a 1,000-foot concrete cover, upon which a 4-acre park featuring a soccer field and an amphitheatre will eventually be constructed in 2023, and new technology that helps assure safe traveling.

“The cover is really, simply, a bridge that we built that is very wide or very long, however you want to look at it,” said Hays, explaining that the cover has strong structural support on the north and south sides.

Some of the safety features include a sign bridge that can be used to notify drivers of closures or dangers; an alarm system for announcements in case of emergency; a sprinkler system that can drop 3,500 gallons of water per minute in case of a fire; a heat monitoring system equipped with cameras that can help identify the heat source; a responsive lighting system; approximately six air monitoring systems to assess the air quality in the underpass; and nine jet fans that can be activated, one at a time, by the air monitors in case of high levels of air contamination due to traffic or in response to smoke from a fire.

For Hays, one of the most impressive features of the Central 70 project is that all of these systems are automated to work with one another.

“Very early on, CDOT and our management made the decision that public safety was going to be the number-one issue that we wanted to make sure we had addressed with this,” he said. “And so, we made the decision to install the full complement of fire life safety systems within the cover.”

Once demolition of the viaduct happens, CDOT will implement poles with a net surrounding it to prevent anything that falls from injuring a person or damaging property. When it comes to contamination in the area, Hays said that CDOT and Kiewit have taken the proper precautions to test for contaminants beforehand — throughout the construction process and specifically for the viaduct demolition — and to properly treat and dispose of contaminants as they arise.

“There will be dust. We’re demolishing a bridge,” he said. “However, we will have fire hoses on the ground spraying water on the bridge, trying to keep that dust wet and contained and settled. We also put misters on the bridge … to keep all of the demolition activities wet and get that dust to settle in.” Hays explained that during the demolition, CDOT will install four monitors that will alert if air quality standards become an issue.

While some residents have expressed concern about potential heavy metal contaminants, such as lead paint, coming from the viaduct, Hays does not expect it to be a problem. The crew will also monitor the air for heavy metals and if high levels of contamination are detected, they will halt the project and address the issue. Overall, he said that the demolition will be a “surgical process” that will be adjacent to a property for one to two weeks at a time, not months.

“We are going to do it as quickly as we can,” said Hays. “So we’re trying to be good neighbors the best that we can.”

In regard to the potential damage that vibration from the construction may cause to adjacent properties, Kiewit has done a structural analysis of various adjacent homes and businesses to ensure no damage is done.

Overall, Stacia Sellers, the communications manager of the project, said there have not been many complaints about the project from residents of the nearby Globeville and Elyria-Swansea neighborhoods.

“At this point, residents are getting pretty used to construction. I think they’re starting to get a little relieved that the end is in sight,” explained Sellers, who noted that officials made a door-to-door effort to talk to residents about the shift and viaduct demolition.

Sellers reiterated that community connection has been a priority for CDOT, which also plans to offer car wash vouchers to residents. Communication efforts have involved doing in-person contacts, offering kiosks with fact sheets and construction updates, implementing yard signs in the community with a QR code and link to their website and providing virtual office hours and meetings.

Through these efforts, the CDOT team aims to keep the community informed and prepared for any changes, especially when it comes to street closures. To stay up-to-date, Sellers recommends community members go to the Central 70 website and register for updates.

The changes being made can be hard to conceptualize, which is why CDOT is getting the word out now and hosting a “More than an Interstate” event on Saturday, allowing the public to take a tour of the Central 70 project.

“We understand that this is going to be a change. We understand there’s going to be a learning curve associated with driving through this,” Hays said. “Our hope is that through these educational efforts […] we end up with folks not looking around and not paying attention to driving. We want them to drive.”

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