Douglas County, Castle Rock to rebuild I-25 frontage road

Street has become focus of safety concerns for area residents

Ellis Arnold
Posted 3/6/23

Ahead of the opening of a new Interstate 25 interchange, a major road for residents in the south Castle Rock area will undergo upgrades in a project that comes amid safety concerns for the two-lane road.

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Douglas County, Castle Rock to rebuild I-25 frontage road

Street has become focus of safety concerns for area residents


Ahead of the opening of a new Interstate 25 interchange, a major road for residents in the south Castle Rock area will undergo upgrades in a project that comes amid safety concerns for the two-lane road.

“The reality is I think we were all brought together by the tragedy of the three deaths that we’ve seen in the last six months on this stretch of road,” George Teal, a Douglas County commissioner, said during a Feb. 28 town hall meeting about the street.

Area residents had raised the idea of holding the meeting, Teal said after a question-and-answer session where the crowd voiced several concerns about traffic and safety along the road.

Today, a pair of two-lane frontage roads sit along either side of I-25 in the south Castle Rock area, running south toward Larkspur. The project planned by Douglas County and the Town of Castle Rock will rebuild the road that sits west of the highway.

A Larkspur resident called the road a “main thoroughfare” that allows people to get around, including to Castle Rock.

Teams will move the road to the west side of the railroad tracks that also run parallel to I-25 and will add features that could make the road safer to drive.

The project could start this summer and may take several years to complete all the segments. Here’s a look at what will change and what’s already underway.

Nearby development affects timing

Officials will close the existing frontage road to make room for new ramps onto I-25, according to Aaron Monks, a project manager for Castle Rock.

In the next couple years, teams will build a new interchange to provide access to I-25 at Crystal Valley Parkway in the south Castle Rock area — where Territorial Road currently meets the frontage road — a short distance away from the future relocated frontage road.

All told, the west frontage road will be relocated and rebuilt from Plum Creek Parkway, in central Castle Rock, down south to Tomah Road outside town limits.

The southmost segment, handled by Douglas County, could see construction from this fall through summer or fall 2024.

A middle segment handled by Castle Rock — roughly from Crystal Valley Parkway south to the town limits — could see work from this summer through the next 12 months.

The northern segment’s timeline is less clear, potentially several years away from seeing construction. The relocated frontage road will be named Dawson Trails Boulevard, according to the county.

“In the future, 2030, Dawson Trails Blvd. will be extended north from Crystal Valley Parkway to Plum Creek Parkway, and the timing of development on the west side of the BNSF railroad tracks dictates the timing of this segment,” the county wrote on its website.

Added features

The southmost segment will remain a two-lane road — one lane in each direction — but it will gain a 12-foot painted median to provide access to the properties that sit west of the railroad tracks, according to the county.

That part of the new road also comes with about 4-foot shoulders and 2-foot gravel edges, according to the project plan.

The middle segment will still be a two-lane road at first, flanked by a 10-foot landscape area on one side and a 2-foot temporary shoulder on the other.

But at some point in the future, officials expect it to greatly expand, with two lanes in each direction and a “raised median and/or turn lane” in the middle, the plan says. On either edge of the road will be 6-foot bike lanes, 10-foot landscape areas and 10-foot sidewalks.

“As the development, Dawson Trails development, continues to expand and grow, they will be required to widen it to four lanes” on that middle segment, Monks said during the meeting.

The project will include left turn lanes on Bear Dance Drive and Tomah Road to connect with the new frontage road, said Art Griffith, a Douglas County project manager.

“I just want to point out the existing west I-25 frontage road will stay open through most of the interchange construction, and it will permanently stay open between Tomah and Sky View (Lane)” further to the south, Griffith told the crowd.

On the north end of the project area, the existing frontage road will see a “road closed” barrier at Yucca Hills Road, a short drive south of Plum Creek Parkway.

Guardrail removed

An official from the Colorado Department of Transportation, often called CDOT, said the agency is removing guardrail along the frontage road, a statement that elicited applause from the audience.

One commenter urged CDOT to continue removing guardrail, implying the rail creates a safety issue for the two-lane road and that it’s unnecessary because of existing separation between I-25 and the road.

“We have taken a look at the project and now that it is built, we have (reevaluated), and we are removing about 11,000 linear feet of guardrail,” said Stephanie Alanis, a CDOT program engineer.

About 10,000 feet have been removed already, with 2,000 left to go, and CDOT was to finish in early March depending on weather, Alanis said.

Officials also have lowered the speed limit, Alanis noted. Some commenters raised the issue of drivers passing other cars on the narrow road, a problem one man attributed to the lower speed limit.

But road management involves tradeoffs, Alanis said, adding: “You lower the design speed limit, and that allows us to also take away some of the guardrails.”

Concerns over growth, safety

Four teens were involved in a head-on car collision on the frontage road around midnight Aug. 5. A man in a Toyota crossed into oncoming traffic and struck a pick-up truck carrying the teens.

Two of the 17-year-old passengers in the truck died in the accident, and an unidentified driver and another passenger were both taken to area hospitals for moderate to severe injuries.

Authorities suspected the man in the Toyota was driving under the influence.

The crash occurred on the road near mile marker 179, which sits near Territorial Road, according to a map created by a member of the public on the state’s website.

(Teal also noted a third death in recent months, seemingly from another fatal crash on the road in the area.)

One commenter at the town hall meeting felt that accidents are “a direct result” of increased traffic over the last 10 to 15 years.

“What is Douglas County doing to curtail the amount of development going on in the community, to mitigate all this increased traffic going forward?” he asked.

Douglas County Commissioner Abe Laydon responded that regarding growth, the county focuses on ensuring residents can get around.

The project is about “ensuring you’re not stuck in traffic and that your roads aren’t dangerous,” Laydon said.

Open space also factors into growth, said Laydon, noting that county residents recently passed a ballot measure to ensure the county has nearly $300 million through 15 years for open space, parks and historic resources.

“We’ve been able to preserve almost 50% of our county as open space. That also includes Pike National Forest, but by us preserving land, that land (cannot) be developed,” Laydon said.

Douglas County Colorado, I-25, west frontage road, Castle Rock, Larkspur, construction, Crystal Valley interchange


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