A major transportation improvement project is officially underway in Castle Pines! Earlier today, the City of Castle Pines celebrated the groundbreaking of the Happy Canyon Road and Interstate 25 interchange reconstruction project, marking an exciting milestone for a project years in the making.
The celebration brought together Castle Pines Mayor Tracy Engerman, Castle Pines Council Member and Chair of the Douglas County Transportation Forum Steering Committee Deborah Mulvey, Council Member Chris Eubanks, the Douglas County Board of County Commissioners, representatives from the Colorado Department of Transportation (CDOT), project team members from construction contractor Kraemer North America, and other project partners who have helped make this project possible.
The reconstruction will transform one of our community's key connections to I-25, improving safety, reducing congestion, and making travel easier for residents and visitors. Improvements include replacing the existing bridge, adding a second bridge, reconstructing highway ramps, and introducing a new diverging diamond interchange designed to improve traffic flow and accommodate future growth.
What's changing at the interchange?
The project includes several major improvements:
- Two new bridges: Replacing the existing Happy Canyon Road bridge over I-25 and constructing an additional bridge just north of it.
- Reconstructed highway ramps: Improving how drivers enter and exit I-25.
- New traffic signals and intersection improvements: Helping traffic move more safely and efficiently.
- A new diverging diamond interchange: A redesigned interchange that allows drivers to make left turns onto I-25 without crossing oncoming traffic, reducing potential conflicts and improving traffic flow.
What to expect during construction:
Construction activities will begin next week, with the first phase focused on building the new bridge north of the existing Happy Canyon Road bridge. The existing bridge will remain open during this phase, allowing drivers to continue traveling across I-25 and maintaining access to the highway from Happy Canyon Road.
As work gets underway next week, drivers should anticipate:
- Initial nighttime lane closures are scheduled for November 16–19, between 7 p.m. and 6 a.m., as crews begin shifting I-25 travel lanes to make room for construction.
- Narrowed and shifted travel lanes on I-25, with four lanes maintained in each direction for most of construction.
- Reduced speed limits through the construction zone.
The first phase is expected to continue through summer 2027, with the overall project anticipated to be completed by early 2029.
We know construction can be inconvenient, and we appreciate your patience as crews work to bring these important improvements to our community.
Stay informed throughout construction:
The City will continue to share updates about construction progress, upcoming traffic changes, and anticipated closures to help you plan your travels.
Visit CastlePinesCO.gov/HCInterchange to learn more about the project and explore the future interchange design.