Four Corners

General map showing the location of the four corners project areaFour Corners Intersection Improvements

Castle Rock is one of the fastest-growing towns in Colorado. This growth brings many positive changes to our community but also has led to some traffic safety and operational issues as this growth outpaces funding for transportation improvements. In 2017, the Castle Rock Transportation Master Plan identified the need for improvements at the Four Corners intersection, located approximately two miles east of Downtown. This intersection of Founders Parkway, Fifth Street, State Highway 86, and Ridge Road currently serves more than 30,000 vehicles per day – a number that is expected to increase to more than 48,000 vehicles per day by 2040. This intersection also has a high crash rate and lacks connections/safe accommodations for bicyclists and pedestrians.   

To address these safety and operational issues, the Town plans to improve the intersection with a solution that will last well into the future. The Town successfully secured regional funds through the Denver Regional Council of Governments to complete design and construction of these improvements. Design efforts began in late 2020, and the project is expected to begin construction in 2022.

Public Engagement

Join the project mailing list to receive notice of these planned input opportunities and to stay informed about project progress.

March 9, 2021 online open house – Watch the open house recording or view the presentation slides (pdf) to learn more about the improvement alternatives that were considered and how they were evaluated.

Summer 2021 open house – Give feedback regarding the preliminary (30%) design that will be used to optimize improvements and minimize impacts as the design is finalized. 

Watch the March 9 Four Corners Intersection Improvement Open House

Alternatives Considered

Four Corners Alternative - Quadrant Road Intersection (Northeast)
Four Corners Alternative - Improved Signalized Intersection
Four Corners Alternative - Partial Continuous Flow Intersection (CFI)
Four Corners Alternative - Two/Three Lane Roundabout

Project Details


  • Improve traffic operations
  • Enhance safety and mobility through the intersection
  • Develop a cost-effective immediate solution that can flex to accommodate future travel patterns and multimodal demand into the year 2040

Project Area


Key Project Tasks

  • Understand traffic conditions currently present and anticipated in year 2040
  • Develop and evaluate alternatives to select a recommended alternative 
  • Prepare preliminary and final design leading to plans for construction 
  • Obtain required approvals from the Colorado Department of Transportation and Federal Highway Administration through frequent coordination 
  • Involve community members and stakeholders to optimize the design and minimize impacts

Schedule Highlights

A graphical timeline of the four corners project. Construction anticipated Summer of 2022.