Twin Tunnels expansion nearing first milestone |

Twin Tunnels expansion nearing first milestone

The Twin Tunnels construction project is slated to meet the first of its major completion milestones before the end of the month, according to an update from the project’s contractors.

Sometime between now and Halloween crews expect to open three lanes of eastbound Interstate 70 traffic between Hidden Valley and the bottom of Floyd Hill.

The reopening of this section of highway means drivers will have three lanes at their disposal all the way to Denver, once they navigate the Twin Tunnel detour.

The tunnel bore should be open to three lanes of traffic by the end of the year, but if all goes well the lanes could be open before mid-December and Christmas travel, said Thad Noll, assistant Summit County manager, in an email.

The reopening between now and Halloween of eastbound I-70 between Hidden Valley and the bottom of Floyd Hill means drivers will have three lanes at their disposal all the way to Denver.

Once the third lane is open it will start at the East Idaho Springs on-ramp and continue all the way to Denver, Noll said.

In preparation for the opening of the expansion from Hidden Valley to Floyd Hill, construction crews are installing permanent guardrailing and signs, and removing the temporary barriers that have been in place, the update stated. A final layer of asphalt and striping will soon follow.

Construction officials plan to release additional information in the coming weeks regarding the work required to widen the highway on the west side of the tunnel and the impacts this work could have on I-70 travelers.

For more information about the project thus far, visit

In other parts of Summit County, Noll said four full lanes of travel on Colorado Highway 9 between Tiger Road and Agape Church in Breckenridge should also be open by the end of the month.

The new bridge that crosses the Blue River will remain as it is for the winter, Noll said, with one side complete and the other to be finished next spring. Construction crews hope to remove the culverts in April before the spring runoff, which will help accelerate summer construction.

A final layer of asphalt between Tiger Road and the new bridge will be laid in the next week or so.

As for Highway 9’s future, Noll said the county has received preliminary approval from the Colorado Department of Transportation to fund the four-lane section between Summit High School and Summit Medical Center.

The likely route will be over a part of Iron Springs parcel, which will shorten the highway by ½ mile and improve safety, Noll said. That route still requires approval pursuant to the National Environmental Policy Act.

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