With one major highway project already under way on Interstate 70, Colorado Department of Transportation officials are now working on their next move to maximize the capacity of one of the state’s more congested highway corridors.
The new peak-period shoulder lane will utilize the asphalt outside the existing highway lanes to create a reversible third lane that can be used to help improve traffic flows in either direction. The lane will be tolled, or managed, and run from Empire Junction all the way through to the Twin Tunnels where it will join up with a new, permanent third lane.
The Twin Tunnels project, a $106 million expansion near Idaho Springs, will add a third lane of traffic on the eastbound side of I-70 through an area that creates a bottleneck during heavy travel days, particularly on Sunday afternoons in the winter when many skiers are returning to Denver.
That widening project and the hard-shoulder lane are intended to work together to improve the congestion on Interstate 70.
“From an engineering conceptual (standpoint) there’s benefit to doing it,” CDOT Region 1 engineer Tony DeVito said. “We’re getting about 10 minutes of operational benefit with the Twin Tunnels and we get about 30 minutes of operational benefits with the combined 13-mile (shoulder) lane.”
The hard-shoulder lane is a interim solution. A recent study on the Interstate 70 corridor calls for more sweeping permanent solutions, including widening the highway permanently through the mountain corridor and offsetting vehicle congestion with an advanced guideway system, or high-speed rail, that will run adjacent to the highway. But those more expensive proposals are only in the early phases of a long-term planning process.
In the meantime, the hard-shoulder lane — if the project gets a nod from local stakeholders and funding becomes available — is tentatively slated for construction in the summer of 2014. It’s still unclear when it would be completed.
The lane, although reversible and temporary, is different from the proposed “zipper lane” project that was scrapped last year. That proposal would have required taking a westbound lane and converting it to an eastbound lane, or vice versa, when heavy traffic demanded increased capacity on one side of the highway.
“The Twin Tunnels failed the zipper lane,” DeVito said. “Trying to squeeze a reversible lane through the obsolete Twin Tunnels wasn’t going to work, and that’s really what gave birth to the Twin Tunnels visioning, which is really now under way.”
CDOT engineers also realized it wasn’t practical to subtract a westbound lane to support eastbound traffic, as it would cause delays and problems on the other side of the highway.
The hard-shoulder lane is expected to cost approximately $30 million and has been proven to work effectively in other states, including Minnesota. Local officials say they’re supportive of the plan.
“I think it’s a really important option,” Summit County Commissioner Dan Gibbs said. “When you look at improvements along the I-70 corridor, I think that would be money well spent. They’re looking at a very aggressive time frame ... and so I’m excited. The trends and the congestion reflect that freeing up an additional lane for use eastbound and use that for a managed lane, I think is a real positive and it could add to safety on the corridor as well.”