DENVER -- The Colorado Department of Transportation expects to have an official groundbreaking on the Central 70 project in the next few weeks.
The $1.17 billion project will reconstruct a 10-mile stretch of I-70 between Brighton Boulevard and Chambers Road, add one new Express Lane in each direction, remove the aging 54-year old viaduct, lower the interstate between Brighton and Colorado boulevards, and place a 4-acre park over a portion of the lowered interstate.
The project has been in the works for more than 15 years.
"We've been at this 15 years now," Central 70's Rebecca White said. "We completed the environment study about a year ago. The Federal government gave the go ahead about a year ago, but for 14 years leading up to that, we've been trying to figure out what to do with that bridge."
That bridge is the two mile viaduct above part of Denver.
White said the community didn't want the bridge to be rebuilt because it would still be a giant piece of infrastructure in their community.
"When we flipped that idea on its head, and took the highway from 30 feet in air, to 30 feet below ground, the community said you're getting closer," White said. "Then we added 4 acre cover and finally got some level of support that allowed us to move forward."
The viaduct will be brought down in pieces.
"A lot of people might assume we have to take bridge down immediately, as projects starts, but what our team is going to do is going to start building that lowered section,"White said.
After digging out the lower section, CDOT will move traffic down, then take the viaduct down.
The Central 70 project will replace four bridges on CDOT's list of bridges that are designated as structurally deficient or functionally obsolete, and rated “poor."
- The I-70 viaduct between Brighton Blvd. and Colorado Blvd.
- The I-270 flyover from eastbound I-270 to eastbound I-70
- I-70 (both eastbound and westbound) over the railroad tracks at Quebec
The project will also newly construct or rebuild 17 other bridges.
- I-70 over Brighton
- Union Pacific Railroad bridge over I-70
- York Street over I-70
- Josephine over I-70
- Columbine over I-70
- Clayton St over I-70
- Fillmore over I-70
- Steele/Vasquez over I-70
- Cook Street over I-70
- Monroe Street over I-70
- Colorado Blvd over I-70
- I-70 over Dahlia
- I-70 over Holly
- I-70 over Monaco
- I-70 over Quebec
- I-70 over Peoria
- BNSF Railroad over I-70
CDOT says the two-mile stretch of highway that is being moved underground will be well-lit to keep traffic moving.
Long-time residents of the area remember when the runways at Stapleton Airport crossed I-70, creating tunnels that traffic used. Traffic often backed up entering those dark tunnels.
"The design for [the new] covered section will be completely different," White said. "There's a very human reaction to start braking in darkness."
White said the new tunnels will be light-filled.
"[It's] designed so a motorist can come through it without any encouragement to brake or slow."
She compared the underground tunnels to the new twin tunnels, or Veterans Memorial Tunnels, near Idaho Springs, and how bright those tunnels are after an expansion project a few years ago.
The completion goal has been set for 2022.
Learn more about the project here .