I-25 South Gap Environmental Assessment: Monument to Castle Rock | Environmental Assessment
About the Project
Numerous alternatives were evaluated to improve the Gap, with three key needs identified: improve travel reliability, safety and mobility. The proposed improvements are shown to best meet the project's purpose and needs, as documented in the Environmental Assessment:
- Widen 18 miles of I-25 from south of Castle Rock to Monument by adding an Express Lane in each direction. Drivers would have the choice of using the Express Lane for a reliable trip in exchange for a variable toll or ride the two existing general purpose lanes for free. Carpoolers (vehicles with 3 or more people) could ride the Express Lane for free. This is likely the best option that offers motorists trip reliability over the long-term.
- Widen shoulders outside and inside the travel lanes
- Add new wildlife crossings
- Add new overlay to existing pavement
- Repair or replace bridges
- Modernize highway with communications and power to enable advanced technology
- Estimated project cost: $350 million
- Construction scheduled to begin summer of 2018, pending funding
Project Map
The Federal Highway Administration (FHWA) has determined that the proposed action described in the I-25 South Gap Environmental Assessment (EA) will have no significant impact on the human or natural environment. For the full report, contact the project team.
The South Gap
The South Gap is an 18-mile stretch of I-25 from south of Castle Rock to Monument. It is the only four lane section of I-25 from Denver to Colorado Springs. Over the years, congestion, crashes and delays have grown due to population growth and more people using the road.
Improving the Gap is a top statewide priority. CDOT has been working with localities and the public along the corridor to develop and complete the study phase and the Environmental Assessment. CDOT will be ready to start construction summer of 2018, pending funding.
Environmental Assessment
For more than a year, CDOT has undertaken a Planning and Environmental Linkages study to identify a long-term vision for the 34-mile stretch of I-25 from Monument to C-470. As a result of the study, CDOT identified the Gap as the most urgent priority.
To address that priority, CDOT has conducted an Environmental Assessment, with the goal of having this stretch of the highway ready for construction in 2018.
As documented by the Environmental Assessment, Express Lanes are the preferred alternative because they best meet the purpose and need of the project to improve safety, travel reliability and mobility.
Two public hearings were held in May 2018, as well as ongoing public outreach and collaboration with public officials and localities along the corridor. The public had 30 days to comment on the project following the release and posting of the EA. Those comments are being reviewed and will be responded to, with documentation posted on this site by late June.
I-25 South Gap: Monument to Castle Rock Environmental Assessment
In June 2018, CDOT and the Federal Highway Administration (FHWA) completed the National Environmental Policy Act (NEPA) analysis for the I-25 South Gap Project. The FHWA provided the final approval for the project to move to final design and construction.
In May 2018, CDOT and FHWA released the I-25 South Gap: Monument to Castle Rock Environmental Assessment (EA) for public comment. In June 2018, the FHWA issued the Finding of No Significant Impact, which approved the planned project for construction and responded to public comment on the EA.
Preferred Alternative:
CDOT proposed expanding I-25 between Monument and Castle Rock by:
- adding a new tolled Express Lane in each direction;
- widening shoulders;
- replacing outdated infrastructure;
- addressing design deficiencies of the aging roadway;
- adding wildlife underpasses; and
- modernizing the facility with improved drainage, lighting, communications, power and signage.
All improvements are planned within CDOT's right of way; no property acquisition is anticipated.
EA Review
For access to the Environmental Assessment, submit a records request.
Public Hearings & Responses
Members of the public were invited to attend public hearings to provide input on the proposed project and EA conclusions. CDOT presented the preferred alternative for the I-25 South Gap Project, findings of the EA, and information about the next steps in the project schedule. Two public hearings for this project were held in Castle Rock and Colorado Springs.
CDOT and FHWA reviewed and considered all comments. Through this process, CDOT and FHWA decided to move forward with the preferred alternative. All comments received during the comment period, including at the hearing, are part of the project record and received a written response, which is included with the Finding of No Significant Impact (FONSI) report.
Project funding was secured, and construction began in summer 2018.
