Gov. John Hickenlooper joined Colorado Dept. of Transportation and federal, state and local officials to preview the new eastbound Interstate 70 Twin Tunnel bore near Idaho Springs on Dec. 7. 
After just eight months of rock blasting, rock bolting and paving, the third lane of eastbound I-70 between east of Idaho Springs to U.S. 6, including through the Twin Tunnels, opened to traffic.

Photo courtesy of CDOT
The $106-million Twin Tunnels Project added one eastbound lane.
Photo courtesy of CDOT
This is the first of several projects designed to improve safety and mobility along the I-70 mountain corridor.

“The I-70 mountain corridor is a critical component of our transportation system as well as Colorado’s economy,” Hickenlooper said. “This project serves as a stepping stone for future improvements to help ensure safe and efficient travel. We thank CDOT for working to provide practical and innovative transportation solutions for the I-70 mountain corridor.” 

By widening eastbound I-70 through the Twin Tunnels, CDOT will be able to build an Express Lane for eastbound peak periods that uses the shoulder lane. Using the existing wide shoulder from Empire Junction through Idaho Springs, motorists will be able to travel the peak period shoulder lane by paying a toll only during peak travel times. In return, they will have a reliable travel option with consistent speeds that will save motorists an average of 30 minutes in travel time.

The $106-million Twin Tunnels Project added one eastbound lane from the East Idaho Springs interchange to U.S. 6, including expanding the eastbound tunnel to include three lanes, shoulders, improved lighting and a wider entrance to encourage eastbound traffic to continue driving into the tunnel without braking.

Minor work off the roadway will continue next spring, and the tunnel project will be completed in spring 2014. The peak-period shoulder lane will be constructed and open to traffic in summer 2015.

“We recognize the importance of addressing the congestion issues on the I-70 mountain corridor, but given the funding constraints, we must look for solutions within our means,” said CDOT Executive Director Don Hunt. “The peak-period shoulder lane allows us to get the most out of our existing system while further improving safety and mobility,”

Although the new lane through the eastbound Twin Tunnel is part of the Express Lane, the fees will be waived until the peak-period shoulder lane is complete and open. Meanwhile, motorists can travel the lane for free.

Widening the eastbound tunnel to accommodate three lanes of traffic involved first using large drilling equipment to create holes in the rock in which explosives can be packed for a controlled, localized blast that removes a targeted section of rock. Kraemer-Obayashi, the joint venture contractor, used two sets of drilling equipment to speed up the tunnel blasting and widening process. 

This is the first of several projects designed to improve safety and mobility along the I-70 mountain corridor. The projects are expected to collectively reduce roadway congestion and improve travel times and safety by reducing accidents by an estimated 35% and saving Sunday travelers approximately  $11.4 million in travel time and fuel costs in 2014.