After completing a significant upgrade on eastbound I-70 with a third eastbound lane through the Twin Tunnels, near Idaho Springs, the Colorado Department of Transportation wants to proceed with expanding the westbound side of the tunnel.
“We need official permission from transportation commission ... we're hopeful the answer will be a yes,” said Jim Bemelen, recently retired I-70 mountain corridor project manager. The commissioners will hear the request and decide on whether to approve the needed $50 million in mid-January, Bemelen said.
If the project is approved work would begin next spring, after the ski season, and be completed in time for the start of the 2014-2015 season. By doing the project now, CDOT could save some money by using equipment and construction infrastructure that's already in place.
According to Bemelen, westbound traffic would use the new eastbound tunnel lanes, while eastbound traffic would once again detour around the construction zone on the frontage road south of Clear Creek.
“That detour worked wonderfully, compared to what we thought it would,” Bemelen said, explaining that Clear Creek County helped spur the idea to widen the westbound side of the Twin Tunnels.
CDOT was set to start improving corridor along the creek with a trailhead and other recreational amenities, but county leaders offered to delay that work for year to enable the immediate start of construction on the westbound tunnels.
“We're only talking about the tunnel itself, not highway on either side,” Bemelen said, adding that the westbound tunnel project would open the door for construction of a new westbound peak-period shoulder lane project, like the one that's already planned for the eastbound section from Empire Junction to Floyd Hill.
CDOT has already approved proceeding with design and environmental clearance activities for the westbound Twin Tunnels bore. The agenct estimates it can save at least $5 million by continuing now with the westbound tunnel project.
The scope of the westbound project would include widening the tunnel, building new tunnel portals and excavating a portion of the rock walls on either end of the tunnel so crews can get the tunnel liner framework inside the tunnel.