A 15-mile reversible lane from Floyd Hill to Empire Junction could ease Sunday afternoon congestion on Interstate 70, according to the Colorado Department of Transportation. But one Clear Creek commissioner is concerned that it wouldn’t be a workable solution.

If a “zipper lane” is approved by CDOT, it could be implemented as soon as the 2011-12 ski season. CDOT announced the results of the first of two studies last week.

While CDOT found the results encouraging, Kevin O’Malley, chairman of the Clear Creek commissioners, is concerned about how the highway configuration would be affected by weather and traffic accidents, and about the potential for negative impacts on emergency services and westbound traffic.

The zipper lane involves a movable barrier with segments shifted by a machine. The plan, which CDOT began studying in 2009, would create an additional lane for eastbound traffic by taking a lane away from the westbound side. If constructed as proposed, the zipper lane would not be able to add a lane for westbound traffic and take one away from the eastbound side.

The study’s conclusions

The study found that a zipper lane could reduce travel times for those going east on I-70 by about half. The study also found that it would more than double travel time for those going west.

CDOT is starting the second phase of the study and examining snow removal, emergency response and other issues. That part of the study will likely be completed in early 2011.

The estimated cost of the system is between $30 million and $35 million. CDOT has not discussed funding sources.

“While reversible lanes have been used with success in several states, they have not been used under the challenging conditions presented on the I-70 west mountain corridor,” said Tony DeVito, CDOT Region 1 director. “… We are encouraged about the prospect of this project, but we are proceeding cautiously to assure it provides a safe short-term solution to traffic without causing unacceptable problems for those traveling in the opposite direction or for the local communities.”

O’Malley’s concerns

The project’s strongpoint, according to O’Malley, is that it would improve traffic flow heading east on Sunday afternoons. But he’s not sold on living with the inevitable side effects.

“It would come at a cost to the people traveling westbound. It would double the time it takes to travel that 15-mile stretch …,” O’Malley said.

O’Malley said the study has not yet looked at how the lane would impact emergency services or how the realigned traffic would be affected by accidents.

The county has its worst traffic jams when it is snowing, and O’Malley said the zipper lane likely would not be an option during a snowstorm.

“It looks like the preliminary cost estimate is about $35 million, and the zipper lane would be usable about 17 times per year,” O’Malley said. “But that doesn’t include the Sundays when it might be snowing, (and) so effectively it would be less than 17 days.”

O’Malley said the zipper lane is a useful idea that has been employed around the country but has never been used in a configuration where it leaves only one lane in the other direction.

“It’s always been used on highways that have more than two lanes in each direction,” O’Malley said.

O’Malley said he believes CDOT’s study is the right approach to analyzing the possibilities.

“They are trying to take a very comprehensive look at the issue and hopefully (will) make a reasonable determination,” O’Malley said.

Contact Ian Neligh at couranteditor@evergreenco.com, and check www.clearcreekcourant.com for updates and breaking news.