Along a winding mountain stretch of Interstate 70, concrete towers are rising as high as 120 feet in the air. Massive drill bits the width of a small trampoline are boring into the ground. And workers have now spent over 1 million hours laboring on an infrastructure project whose price tag has surpassed $900 million.
Yet much of the work is going over drivers’ heads — literally.
The ,ɳ targets a notorious segment of I-70 that stretches from west of Evergreen to eastern Idaho Springs, has entered a new phase marked by the construction of soaring bridges that will eventually carry motorists across an entirely new segment of the interstate.
“One of the big stories is, ‘How do you build this near-$1 billion project in a tight canyon — with the grade, with the slope — without basically shutting down I-70?’” said Jonathan Godes, the executive director of the I-70 Coalition, a consortium of mountain towns and businesses that advocates for investments in the interstate through the mountain corridor.
Thatap been the goal from the beginning for the , which says the three-year-old project — now at its midpoint — should result in smoother travel days for drivers.
Gone are the routine 20-minute traffic holds that delayed motorists during weekdays as crews blasted away thousands of tons of rock. Now, entire new sections of the interstate are being constructed above the road’s current alignment, allowing for traffic to flow unabated.
“That was a focus in (the) design,” said Kurt Kionka, the Floyd Hill project director. “We understand the importance of I-70 to the state of Colorado and the country as a whole. We know what happens when I-70 stalls and shuts down.”
The project, which spans eight miles of interstate that has long been a pain point for motorists, represents one of the most sweeping overhauls of the I-70 mountain corridor in decades. It’s also CDOT’s largest single road project now underway.
When finished, CDOT officials say it will relieve — or at least reduce — congestion primarily by straightening and widening roadways. That will allow for greater speeds and improved visibility thanks to gentler bends along the corridor, which handles heavy traffic during the ski season and busy mountain travel periods in the summer.
Over 200 rock blasts have been conducted since work began in July 2023, and 1 million cubic yards of earth have been moved to help realign I-70 and reduce sharp turns. One rock face on the projectap western end has been cut back about 150 feet at its deepest point, according to CDOT officials.
Project enters next phase
The projectap focus is now shifting from excavation to road and bridge construction.
Ten bridges will be built or reconstructed to support I-70’s new alignment, a section of which will carry motorists in both directions across Clear Creek. Crews will build the bridges out in 15-foot sections in both directions, eventually meeting mid-air. The longest bridge will be about 6,000 feet long and span 350 feet between its supporting towers, or piers.
While the most onerous traffic delays — the 20-minute holds — are largely over, Kionka said, motorists should still expect some impacts for the remainder of the project, including occasional traffic shifts, closures and detours.
Officials say the new westbound I-70 lanes are on track to open by the end of 2027, with the eastbound lanes opening by the end of 2028. The entire project is expected to finish in 2029.
What will stand out is that the westbound bridges — forming a one-mile viaduct — will carry traffic going that direction to the left of the mostly on-ground eastbound lanes for a good distance as drivers enter the canyon, out of the usual alignment. After cutting over a hill, the westbound lanes will cross back over to the right side. That is among the design elements that will help straighten the roadway.
CDOT is also adding a third lane to westbound I-70 in the form of a 24/7 tolled express lane west of Homestead Road to the Colorado Boulevard/Idaho Springs exit, which is where an existing part-time express lane operates on the shoulder.
“It really boils down to fixing the bottleneck in the westbound direction, where it drops from three lanes down to two, and then safety throughout the corridor as well,” Kionka said. He added that one of the projectap goals is to increase safe speeds, particularly around curves, to 55 mph, up from 45 mph.
Off the highway, the project will add a new, two-mile portion of frontage road between the U.S. 6 and Hidden Valley/Central City Parkway exits, which will help support detours off I-70.
Other aspects of the project include changes and extensions to on-ramps; installing several roundabouts on U.S. 40 and at the I-70 and Hidden Valley/Central City interchange; resurfacing and other improvements to the Clear Creek Greenway trail for pedestrians and cyclists; and implementing wildlife and environmental protections, including two permanent air quality monitors.
Altogether, officials hope the improvements will not only alleviate congestion and safety issues, but also ensure the area can withstand traffic trends well into the future.
A 2021 traffic study projected that travel time between westbound I-70 from Evergreen Parkway to the Mt. Blue Sky exit in Idaho Springs could take 90 minutes on a peak winter day by 2045. The Floyd Hill Project is expected to reduce that time to just over 30 minutes.
Costs rise to $900 million
Officials remain confident that the project will remain on track for its 2029 completion, even as cost pressures have caused the costs to rise by $200 million above CDOT’s original forecast.
In 2020, the project was expected to cost $700 million, but inflation, which has driven up the costs of materials, has pushed that figure to $905 million, Kionka said.
Most of the projectap funding is coming from state dollars, though officials did receive $100 million from the federal Infrastructure Investment and Jobs Act of 2021 — the largest federal grant in CDOT history, according to Kionka.
Of all the infrastructure projects Kionka’s witnessed across his more than 20-year tenure at CDOT, he said Floyd Hill ranked near the top in terms of scale. He likened it to the 12 miles of elevated highway CDOT built in Glenwood Canyon in the 1980s and early 1990s.
Godes, the I-70 coalition executive director, agreed.
“This is one of those engineering marvels people will be talking about decades after itap completed,” Godes said.
He said, too, that efforts to keep the interstate flowing amid construction have been critical for mountain towns.
“(I-70 is) our lifeline to be able to get to the Front Range and to services and doctors, and itap also our economic lifeline,” Godes said. “Itap more than just tourist traffic. … It’s also how we get groceries, how we get supplies. Without I-70, we’re completely cut off.”
Godes believes the improvements from the Floyd Hill Project will “create a more predictable and reliable artery through the mountains.”
