CDOT Invites Public Comment at Idaho Springs Meeting on Proposed Interstate 70 Twin Tunnels Improvements

September 15, 2011 - Central Eastern Colorado/CDOT Region 1 - September 27 Meeting Focuses on One of Corridor’s Biggest Congestion Bottlenecks

IDAHO SPRINGS, CO (September 15, 2011) – The Colorado Department of Transportation (CDOT) encourages the public to participate in a September 27 meeting regarding proposed improvements to immediately address safety issues and improve traffic flow at the Twin Tunnels east of Idaho Springs, one of the most critical congestion bottlenecks on the Interstate 70 (I-70) Mountain Corridor.

CDOT proposes widening the interstate to three eastbound lanes between Idaho Springs and the base of Floyd Hill, enlarging the eastbound bore of the tunnels and addressing safety issues on the eastbound highway curves between the tunnels and Floyd Hill. The Twin Tunnels Environmental Assessment (EA) will define the proposed improvements, provide information on impacts to environmental and community resources, and determine appropriate mitigation to minimize any impacts. The Federal Highway Administration (FHWA) is expected to issue a decision by the fall of 2012.

If the project receives the federally required approvals, construction would begin in the spring of 2013, and will be open to traffic by the end of 2013. During this construction period, eastbound interstate traffic would be rerouted around the Twin Tunnels.

“While other problem areas exist, CDOT - with limited resources - has made Twin Tunnels a priority as one of the first projects on the corridor, because it is one of the most congested areas, with high crash rates, where we can provide immediate relief for eastbound traffic,” said Jim Bemelen, corridor manager for the I-70 Mountain Corridor. “It’s not going to solve all the problems on the corridor but will go a long way to improving safety and reducing travel delays at this location.”

CDOT estimates the project will cost approximately $60 million, Bemelen said.

During the public meeting on September 27, 5:30-7:30 p.m. at the Buffalo Bar, 1617 Miner St., Idaho Springs, CDOT transportation planners will provide information on the proposed improvements and solicit input from the public and other stakeholders. A presentation is scheduled at 6 p.m., during which questions will be answered.

For those unable to attend the meeting, CDOT has provided other opportunities for submitting comments and questions. Comments can be submitted via the project website,, or in writing to: Jim Bemelen, I-70 Mountain Corridor Program Manager, CDOT Region 1, 18500 East Colfax Avenue, Aurora, CO 80011-8017.

Twin Tunnels is the first proposed project in the corridor since the FHWA issued its Record of Decision for the I-70 Mountain Corridor Programmatic Environmental Impact Statement (PEIS) in June.

“Before embarking on this project, we must conduct the necessary federally-required environmental study to examine potential impacts of such a project and how the impacts could be avoided or mitigated,” Bemelen said. “This study is required to receive approval from the Federal Highway Administration so we can proceed with construction as soon as possible.”

A Project Leadership Team (PLT) including representatives from Idaho Springs, Clear Creek County, CDOT and FHWA will oversee the Twin Tunnels EA. A multi-discipline technical team comprised of transportation experts and local stakeholders has been formed to advise the analysis in the EA. Membership of the PLT, the technical team, and other information regarding the Twin Tunnels EA is available on the project website,

Project updates are available via e-mail.  Interested parties are encouraged to visit and click on the cell-phone icon in the upper right-hand corner.  The link takes you to a list of items you can subscribe to, including I-70 Twin Tunnels.


ABOUT THE TWIN TUNNELS EA: The Twin Tunnels Environmental Assessment (EA) is a Tier Two National Environmental Policy Act (NEPA) study conducted by the Colorado Department of Transportation (CDOT) and the Federal Highway Administration (FHWA).  The EA is considering improvements to the Twin Tunnels area east of Idaho Springs to Floyd Hill along the eastbound direction of the Interstate70 Mountain Corridor. The purpose of the proposed project is to improve capacity, mobility, and safety along this stretch of the interstate. The Environmental Assessment will define these improvements and provide information on potential impacts to environmental and community resources and determine appropriate avoidance or mitigation strategies to minimize those impacts. FHWA is expected to issue a decision in late 2012.  The study will honor all commitments in the I-70 Mountain Corridor Programmatic Environmental Impact Statement Record of Decision, and will be conducted in accordance with the I-70 Mountain Corridor Contest Sensitive Solutions guidance.  Additional information is available on the project website