New I-25 Crystal Valley interchange to open in Douglas County in 2027

In Douglas County, development is underway on the highly anticipated Crystal Valley Interchange project. Construction started back in March, but the idea has been in the works since the 1980s. 
The Town of Castle Rock says the interchange will provide a key regional transportation link for the growing southern Douglas County. It will connect the east and west sides of Castle Rock and is expected to improve safety and mobility in the area.
In three short years, drivers on I-25 will see signs for Exit 179 “Crystal Valley Parkway,” about two miles south of the Plum Creek Parkway exit.
“Honestly, I’m kinda excited; I’m probably not the most popular opinion around here,” said Crystal Valley Ranch resident Laurie Probsdorfer.
While some neighbors have expressed concerns over too much development, long-time Castle Rock resident Probsdorfer is looking forward to the connection across I-25 the new interchange will bring.
“I’m really excited about the Costco and all the things that come with the Costco!” said Probsdorfer.
On the west side of I-25, a Costco is expected to open in 2026. Thousands of homes in the “Dawson Trails” development will follow.
The new interchange will make room on the roads for those new residents. Castle Rock says Plum Creek Parkway can’t handle the current traffic volume.
“The congestion at Plum Creek Parkway is creating unsafe conditions, with traffic basically backing up into the through lanes of I-25. This interchange will help with that congestion problem, and create better safety for emergency vehicles” said Aaron Monks, engineering manager for the town of Castle Rock Public Works Department.
The $144 million construction project involves expanding the Crystal Valley Parkway bridge over I-25, building a new roundabout on Crystal Valley Parkway, a new bridge over the railroad, and relocating parts of the frontage roads.
“The existing east frontage road has to be relocated to the east to make room for the abutment and the on- and off-ramps to I-25. The west frontage road has to be closed as well to make room for the on- and off-ramps for southbound I-25,” Monks explained. “Then we have to construct a road that goes from the interchange down to Tomah Road on the west side of I-25 and the BNSF railroad to connect that route for southbound traffic to go into the unincorporated Douglas County.”
While neighbors can expect construction delays in the meantime, including periodic nighttime closures of the highway and frontage road, Castle Rock says it will reduce traffic and improve safety long term.
“We only have two entrances into our community, and they get very backed up, and the community keeps growing and growing, so it will be great to alleviate traffic and get that flow through a little better,” said Probsdorfer.
The interchange should open by summer 2027. But neighbors can expect to see surrounding road changes finish sooner. The Crystal Valley Parkway roundabout should open in November 2024. A new road, Dawson Trails Boulevard, is currently under construction as part of a separate project and should open next summer.
The Crystal Valley Interchange project is a partnership between the town of Castle Rock, Douglas County, and the Colorado Department of Transportation. The town of Castle Rock says the entire project cost is about $143.5 million.
The funding breakdown is as follows:
·         $53.6 million in developer contributions
·         $24 million from Douglas County for the interchange, plus $11 million for the West Frontage Road, which will be known in the future as Dawson Trails Boulevard
·         $8.5 million grant from the Denver Regional Council of Governments
·         $5.4 million BUILD grant from the United States Department of Transportation
·         $1.7 million in Town electric credits
·         $900,000 from BNSF Railway
For more information on the project, click here.