Interstate 70 - Twin Tunnels Project

Project Background

The Twin Tunnels Design and Construction Project was created to alleviate congestion along the I-70 Mountain Corridor. The project includes work to expand eastbound I-70 from Floyd Hill to Idaho Springs, including the eastbound side of the Twin Tunnels. In addition, the project calls for the reconstruction of the bridge over Clear Creek in order to diminish the curve at Hidden Valley.

Upcoming Construction Activity

Beginning in April 2013, eastbound I-70 traffic will be detoured around the tunnel. This detour, will divert traffic from I-70 just west of the Twin Tunnels and return traffic to the highway just west of Hidden Valley. The shift will be in place for about eight months, through late 2013, while the eastbound tunnel is widened. Two lanes of traffic will be open in each direction during high volume traffic periods and pedestrian/bicycle access will continue along CR 314.

Widening the Eastbound Tunnel

State-of-the-art blasting techniques will be used to widen the eastbound tunnel. Once blasting begins, four to six sequences will take place each day stopping traffic for 20-30 minutes each period. Blasting sessions will not take place during high volume traffic periods.

Traffic Impacts

Call 303-327-4034 for the daily traffic impacts. The recording is updated by 10 a.m. daily.

Coping with Construction

During construction keep coming to the mountains for recreation, shopping and dining – travelers will be able to get to and from their destination during construction. CDOT has committed to maintain two lanes of traffic in each direction during high volume traffic periods; and restrict lane closures and blasting operations to low volume travel times, such as week days and overnight.

Information courtesy of CDOT. For the most up to date conditions and information please visit

Recent Updates:

The public is invited to join the Twin Tunnels telephone town hall call on March 13, 2013 at 7:00pm