Local and state highway officials returned from a trip to Minnesota last week armed with a new, and surprisingly simple idea to help ease weekend congestion on Interstate 70: Use the shoulders.
Highway shoulder space has been successfully transformed into an extra lane of travel to help increase traffic flow on Interstate 94 between Minneapolis and St. Paul, a concept officials say might work on I-70.
"We're excited," Colorado Department of Transportation engineer Peter Kozinski. "It's a way of using the pavement we have."
A hard shoulder lane on I-70 would run from the U.S. 40/Empire Junction to the Twin Tunnels, where an eastbound three-laning project is already funded and in the works, and would be used only during peak traffic times to help maximize capacity.
But the concept would require additional research, an environmental process and an estimated $30 million to implement. CDOT is far from giving it the green light.
"What we need to do is then carry on conversations with the locals and see what it really means," Kozinski said. "It's not something we're walking away from at this point, but it's also not something we're just going to charge into blindly."
Though CDOT is beginning to discuss the concept with locals and look at early feasibility research, a hard shoulder lane is not something drivers are likely to see by this summer, or even next summer, Kozinski said.
The hard-shoulder concept, officials say, is not a zipper lane.
The controversial zipper lane idea would have reverted a westbound lane to be used for eastbound traffic during peak travel times, posing safety risks and impacting westbound traffic.
A shoulder lane would have no impact on the opposite side of the highway. With some re-striping, it would allow traffic to use the space on the outside of the highway during heavy traffic times.
The Federal Highway Administration paid for CDOT officials as well as Summit County Commissioner Dan Gibbs and Clear Creek County commissioners to travel to Minnesota last week to observe the hard-shoulder lane system first hand.
"I'm sold on it," Gibbs said this week after returning to Summit County. "In my opinion, that's a real early-action item. That's something that could happen."
A 12-foot shoulder is considered ideal to allow emergency vehicles to bypass traffic to respond to accidents.
The hard shoulder lane as it is implemented in Minnesota, however, preserves 3 feet of bypass space, which, Gibbs said, still turns out to be enough.
"Folks do their best to get out of the way as quickly as possible," Gibbs said. "It might increase the timeframe for emergency services to get to someone by a couple minutes, but it's not a huge gap. It's minimal."
In Colorado, highway shoulders are also used for snow storage when CDOT is plowing the roads. Kozinski said the shoulder lane wouldn't be operational during heavy winter storms.
Though CDOT director Don Hunt has warned Coloradans to be prepared for tolling to be a part of new highway capacity projects in the future, the transportation department hasn't had any discussions on whether a shoulder lane on I-70 would be tolled, according to Kozinski.
"That's a much larger conversation," he said. "We really haven't given that any thought at this point in time."
Congestion-priced tolling is used on hard shoulder lanes in Minnesota, with higher prices during peak hours to encourage drivers to travel during off-peak times.