Local and regional impacts of interchange closure at C-470 and US 85 for bridge demolition

Starting later this week, expect a major closure of Highway 85 or Santa Fe at C-470.

Crews were supposed to begin bridge demolition work as part of the ongoing project to widen Highway 85 on Thursday evening, but that has now been pushed back to Friday night.

Starting at 7 p.m. on Friday, drivers can expect closures on C-470 near the interchange. Drivers will be directed to exit the off-ramps and then will be directed to drive back on the highway on the on-ramps. This will give priority to the most used portion of the highway.

There's also a full closure of Highway 85/Santa Fe from County Line Road to Blakeland Drive in Highlands Ranch.

The work is expected to last through next Thursday morning. It's a very busy interchange that many drivers use every day. 

A spokesperson with Douglas County said nearly 150,000 drivers drive in the area daily. The project has one of the largest regional impacts that will affect drivers nearby and across the Denver metro area.

Nearby business owners said they're likely going to have to close for a few days as the deconstruction of the bridge is underway. Residents also say they've been dealing with the construction for months, but the full closure is a whole new issue.

"I went through here four times yesterday," said Jim Remley. "You gotta be careful."

Remley lives in the Highlands Ranch neighborhood, about a mile away from the interchange.

"I drive there and I never know whether to allow 15 minutes or 45 minutes to get there," said Remley. "Every day, it's hard to get through here. I think the population that lives close to here and uses it regularly has learned to get around it."

Drivers like Remley and many local businesses will be impacted by the nearly week-long closure. Remley also spoke to one of those businesses.

"Businesses are also going to suffer. They said the whole thing has impacted them negatively since it all started, so when it closes down it's going to be worse," said Remley.

The project is all part of the Santa Fe widening project. A $100 million construction project that began in 2022.

"Overall, this project is going to be a dramatic improvement to safety and mobility, along this corridor along 85. It's going to improve traffic flow at all these intersections," said Mike McNish, the area manager of the project.

McNish said the project is the largest road construction project ever in Douglas County and will provide more accessways for pedestrians and cyclists.

"It's going to provide a sidewalk along this whole corridor, where there wasn't a sidewalk before," said McNish. "So it's a dramatic amount of improvements for the people."

McNish added the impact for the drivers is under the bridge demolition where the demo is taking place.

"The demolition is all about public safety," said McNish. "Once we start tearing down pieces and parts of the structure away, it loses its structural integrity. Combines with the fact that it's a massive structure, just over 2,000 cubic yards of concrete."

McNish said crews will be working around the clock until Thursday morning. 20 people will be operating over 15 pieces of equipment and working 12-hour shifts until the road is clear and safe to re-open to traffic.

"In the grand scheme of things, the short-term impacts to traffic will be able to provide a long-term benefit to the people in this area."

Meanwhile, Remley said because of the bridge deconstruction, he'll also be taking other routes for the next week. But he understands, it's for the greater improvements in the area.

"I just look for a year from now, when it's all done, it'll be really nice. In the meantime, it's a pain in the neck some days to have to get around," said Remley.

While construction is underway, the county is also discouraging drivers and traffic on C-470. If you're heading from the mountains and south, or from I-25 and out to the mountains, it's recommended to take 6th Avenue in Denver.

The bridge was originally built in 1968. As part of the project, crews will demolish the old bridge and make way for the second half of the new bridge. Crews will bring in more than 10 million pounds of dirt, to act as a "pillow" and soften the landing of the demolition and falling debris.

During deconstruction, more than 1,000 truckloads will enter and exit the work area removing debris and dirt from the construction site. Drivers in the area should also be on the lookout for large vehicles and trucks removing the debris.

Enough concrete will be removed to cover the football field at Mile High Stadium, twice.

The overall project is expected to finish in fall 2025.

For more information about the project, visit Douglas County's official site. 

During construction, drivers are encouraged to give themselves extra time and take alternate routes. Drivers should also plan ahead and use COtrip to get up-to-date information on traffic.