History & Purpose

CDOT in conjunction with Douglas County, the Town of Castle Rock, and the Federal Highway Administration (FHWA) developed a corridor feasibility study on I-25 within the Town of Castle Rock. This study, the 'I-25 Through Castle Rock Corridor Feasibility Study,' evaluated the existing conditions and determined how to best address safety and accessibility issues.

The following conclusions were derived from the study

CDOT determined that if no improvement or modification was made to the existing trumpet interchange, the operation of the interchange and the overall safety of the ramp movements would drop to unacceptable levels. In addition, the delay that the traveling public would experience when using this interchange would become unacceptable due to proposed development south of Meadows Parkway. There is, as a result, a need to modify the interchange system to make it compatible with both the regional and local planning efforts already in place.

This study recommended the closure of the existing US 85/I-25 Interchange. The existing ramps and bridge would be eliminated and a new overpass would be constructed in order to provide better local mobility across I-25. Traffic currently using the interchange would be routed to the Meadows/Founders Parkway Interchange.

Design and Engineering

Preliminary design of the US 85 & I-25 Interchange Relocation project began early in 1999. After establishing a preliminary design concept, the design team proceeded into final design. The final design phase was completed in the first quarter of 2001.

The design solution was developed to meet the study's recommendations and was closely coordinated with the ongoing South I-25 Corridor and US 85 Corridor EIS to ensure that none of the potential outcomes of the EIS effort are precluded by the design of this project. Please view our Project Description page for design details. NOTE: The South I-25 Corridor and US 85 Corridor EIS has been completed and the ROD has been signed! Read the results: South I-25 Corridor and US 85 Corridor EIS

The Meadows/Founders Parkway Interchange was designed and reconstructed as a high capacity interchange. Construction of the Meadows/Founders Parkway Interchange was completed in August 1999. Since then, traffic studies have confirmed that the interchange will operate at an acceptable level of service through the 2020 design year horizon. In order to improve interstate access to and from US 85, traffic using the US 85 Interchange to access I-25 or I-25 to access US 85 will be redirected through the I-25 Interchange at Meadows/Founders Parkway. Because traffic will be directed to Meadows Parkway to access US 85, improvements are also planned for Meadows Parkway as part of this project.