Castle Rock warns of two weeks of nighttime I-25 lane closures

Southbound I-25 drivers in southern Castle Rock will face two weeks of overnight lane reductions as crews begin one of the most visible structural steps in the Crystal Valley Parkway interchange project. From 8 p.m. to 5 a.m., the highway will drop to a single lane at the bridge location, putting the pinch point squarely on the stretch that serves Douglas County’s fastest-changing growth corridor.

The closures will run Monday through Thursday, April 20-23, and again Monday through Thursday, April 27-30. Castle Rock said the work is needed to safely install bridge girders on the west side of the interchange project area, where those girders will form the foundation for the elevated on- and off-ramps that will connect Crystal Valley Parkway to Interstate 25.

Crews are scheduled to place 35 bridge girders over seven nights, using two large cranes working together and modified semitrucks delivering the materials each night. The town said traffic on the Crystal Valley Parkway bridge over I-25 should not be affected during the girder installation, but drivers should expect intermittent nighttime lane closures through the summer, along with heavier truck traffic and more machinery around the site.

Castle Rock is framing the work as a long-term transportation investment that has been planned since the 1980s and is expected to wrap up in 2027. The project is a joint effort among the town, Douglas County and the Colorado Department of Transportation, and officials say it is meant to improve safety and mobility in southern Castle Rock while serving as a regional link from I-25 into the county.

Town officials say the finished interchange should ease congestion at the Plum Creek Parkway interchange, give residents in the southern part of Castle Rock direct I-25 access and improve emergency response times. Earlier plans for the project included a new roundabout on Crystal Valley Parkway east of I-25, a new bridge over the BNSF Railway tracks west of the interstate and relocated East and West Frontage Road segments.

The interchange is also tied to Dawson Trails, which is expected to bring as many as 5,850 homes and roughly 3.2 million square feet of commercial space, including a Costco. Castle Rock opened the Crystal Valley Parkway bridge and Dawson Trails Boulevard in November 2025 as a major milestone, but the interchange itself is still unfinished. For now, the payoff comes later: two nights a week of southbound delays in exchange for a project town leaders say will reshape access in southern Douglas County for decades.