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I-70 Westbound Twin Tunnels

Stay Informed

Click here to listen to the recording of the March 13 telephone town hall call.

Project Description

The Westbound I-70 Twin Tunnels project will widen the westbound bore of the tunnel in Idaho Springs to about 53-feet. This will accommodate a third lane along westbound I-70 when the highway is eventually widened. Unlike the recent work done along eastbound I-70 to add a third highway lane from Idaho Springs to the bottom of Floyd Hill, this project will only widen the tunnel to accommodate a future third lane. It does not include expanding westbound I-70 to three lanes at this time.

Construction Updates

There will be no lane closures on Friday, April 4, Saturday, April 5 or Sunday, April 6 for the I-70 Twin Tunnels project.

Monday, April 14 through Thursday, April 17:

  • Rock scaling work will be done each day from 8:15 a.m. to 5 p.m. This work will involve periodically stopping traffic in both directions for up to 30 minutes.
  • Also on Monday through Thursday during the overnight hours from 5 p.m. to 5 a.m. there will be various single lane closures in both directions of I-70 while crews do sign work.
  • On Friday, April 18, crews are scheduled to do rock scaling work between 8:15 a.m. and 12:30 p.m. This work will again involve periodically stopping I-70 traffic in both directions for up to 30 minutes.
  • There is no work scheduled for Saturday, April 19, and Sunday, April 20.

Traffic Impacts

  • In March, eastbound I-70 will be reduced to two lanes of travel so crews can put down temporary pavement in the center median area on both sides of the tunnel to shift westbound traffic into the eastbound lanes.
  • In mid to late March there will be minor blasting activity that will require stopping traffic in both directions for about 15 minutes.
  • In late March there will be rock scaling work done to remove large rocks from the mountain face above the highway. This work will require stopping traffic in both directions for up to 30 minutes.
  • In April, eastbound I-70 traffic will move back onto the detour route around the tunnel and westbound traffic will start moving through the eastbound tunnel.

Project benefits

  • Doing this project now saves an estimated $5 million to $7 million because the equipment, resources and detour needed to do the work are already in place.
  • With a wider, brighter tunnel entrance, the traffic flow on westbound I-70   will improve as motorists will be less likely to slow down when approaching the tunnel.
  • Driver safety will also improve with the removal of rock from the walls above the tunnel portals and along the north side of the highway along the outside each portal.
  • This project sets the stage for future westbound I-70 improvements which may use the extra lane for general purpose travel, peak period travel and/or transit.

Project Links

Current lane closures

Traffic cameras

Project Schedule

I-70 Mountain Corridor

Twin Tunnels Newsletters

Contact Us

Project Hotline: 303-327-4034

You may leave a message for a project representative at the end of the recording. Please leave your name, number, and a brief message.

Public Relations Team:
Nadia Garas

Joy Wasendorf

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