The Colorado Dept. of Transportation has started the design for various improvements to the North I-25 corridor. The improvements will be comprised of smaller projects that make up  Phase 1 of the record of decision for the North I-25 Environmental Impact Statement signed on December 29 by the Federal Highway Administration. The study analyzed potential transportation improvements along the I-25 corridor between Fort Collins/Wellington and downtown Denver, as well as along U.S. 85 and U.S. 287.

“The design phase for the North I-25 Reconstruction project is the next step in planning for an effective multi-modal transportation system that is greatly needed for the economic health of northern Colorado,” said CDOT’s Regional Transportation Director Johnny Olson. “Funding still needs to be identified in order to implement the design projects, but we are working to find it in coordination with the FHWA as well as local communities, agencies and industries.”

The first three project locations of Phase 1 improvements include, but are not limited to:

• State Highway 66 to S.H. 56: Tolled Express Lanes (TEL) will be constructed, which will require adding one buffer-separated TEL in each direction of I-25 between S.H. 56 and S.H. 66, and between 120th Avenue and U.S. 36 that will connect with the existing I-25 Express Lane facility into downtown Denver.

•  U.S. 34 Interchange: This project will upgrade six interchanges along I-25, including S.H. 14, Prospect Road, U.S. 34, S.H. 56, Weld County Road 34 and S.H. 7. It should be noted that Phase 1 includes construction of an interchange at U.S. 34 and Centerra Parkway.

• S.H. 392 to S.H. 14: The project will include reconstructing and widening I-25 between S.H. 14 and S.H. 392 to add continuous acceleration-deceleration lanes that will ultimately become part of the eight-lane configuration.

The record of decision, which is the federal document that describes the transportation project, explains the rationale for the project decision, responds to public comments received during the final EIS comment period and makes commitments as to how the project will mitigate impacted environmental resources. The signing of the record of decision allowed CDOT to begin the design phase of projects, which implement the identified improvements, and seek federal, state and other funding sources.

The completion of all elements of Phase 1 is estimated to cost $670 million (in 2009 dollars) and based on current funding, will not be completed until 2035. It is not known at this time when construction will begin, however, updates will be posted on the project’s website at

Funding for additional phases of the preferred alternative or specific projects within those phases will be determined through the statewide planning process carried out by CDOT with the help of the North Front Range Metropolitan Planning Organization, the Denver Regional Council of Governments and the Upper Front Range Transportation Planning Region.