CDOT deploys new winter traffic strategies in wake of February’s four-hour delay
Traveling through the mountain corridor on Interstate 70 has never been a pleasant experience at peak weekend hours during the winter.
Thad Noll, assistant Summit County manager, said as recently as 10 years ago it wasn’t uncommon for ski resort commuters to endure two- to three-hour delays between the High Country and Denver.
However, in those days traffic rarely came to a halt due solely to automobile volume, and it was rare to have traffic backfill onto Summit County’s roads and highways.
The relative bliss of three-hour commutes has given way to a reasonably new traffic phenomenon, Noll said, and last month thousands of commuters received a sobering dose of the new commuter reality as a perfect storm descended on Colorado on Feb. 9, shutting down both Loveland and Berthoud passes, and diverting nearly all of the state’s skier traffic to I-70 through Summit County.
The combination of extreme winter weather, nearby road closures and high traffic volume didn’t just slow travel, but brought it to a more than four-hour halt between Silverthorne and the Eisenhower/Johnson Memorial Tunnel, a seven-mile segment of interstate. With traffic stopped on I-70 and on-ramps and Loveland Pass closed, motorists were backed up all the way to Keystone Resort, and residents found themselves trapped in parking lots, like at Dillon Ridge Shopping Center, with no way to drive around commuters waiting to merge onto the highway.
“We’re talking about a very short segment of road to have that long of a delay,” said Ryan Rice, CDOT director of transportation operations. “A four-hour delay between Silverthorne and the tunnel is absolutely unacceptable.”
Rice filled a relatively new position with CDOT a couple of years ago, Noll said. As director of transportation operations, Rice has been tasked with improving traffic flows given the constraints of the state’s current highway infrastructure.
Rice is the man behind several recent initiatives to ease peak traffic volume on I-70, including CDOT’s traffic alert mobile app, public outreach initiatives encouraging motorists not to travel during peak winter commuting hours and the use of various media to ensure traffic information always is up to date, Noll said.
On Tuesday, March 11, Rice met with the Summit Board of County Commissioners for an update at the Old Breckenridge Courthouse at which he discussed the lessons learned from that February night and strategies CDOT officials have been experimenting with since. Already it appears as if some of the new traffic management policies are paying off.
Surprisingly, Rice said, I-70 traffic woes do not materialize west of the Eisenhower/Johnson Memorial Tunnel, which typically bears the brunt of traffic volume. Instead, he said, the source of the traffic begins east of the tunnel in that first steep and windy descent toward the Front Range.
Cars tend to zip through the tunnel, Rice said, but as they exit on the Clear Creek County side of the bore motorists have the tendency to slow down dramatically — even under good driving conditions — as they make their way to Georgetown. When the roads are snowy and icy, traffic east of the tunnel can slow significantly, backing cars up at times all the way to Frisco.
How CDOT used to handle those traffic jams also contributed to greater delays, Rice said. Because cars have to be cleared out of the tunnel for safety purposes, CDOT would meter, or pause, traffic just before the tunnel until the cars up ahead made their way through.
What CDOT officials discovered, especially during last month’s incident, is trying to get an automobile moving again — even a well-equipped one — on a 7 percent uphill grade is a tall order. In a lot of cases cars and trucks spin out and block traffic, which only further delays travel.
In an effort to mitigate those exacerbating factors, CDOT just recently employed two new traffic strategies: stopping traffic well before the tunnel and experimenting with a concept known as continuous flow metering.
The first strategy is relatively simple, Rice said. Instead of stopping traffic at the tunnel, CDOT officials, with the help of the Colorado State Patrol and local law enforcement, began stopping traffic at milepost 205, the Silverthorne/Dillon exit, or at milepost 207. That stretch of highway represents the final segment of flat road before the uphill charge to the tunnel. The idea is to stop traffic there in an effort to keep spurts of cars moving up the hill and reduce the number of spinouts, Rice said.
Local residents may have noticed the second strategy of continuous flow metering being employed by law enforcement officials at on-ramps to control the flow of traffic onto I-70. The concept is the same as the red and green traffic lights commonly posted just before traffic merges onto a highway, Rice said, and the strategy is to regulate the number of cars entering the interstate to ensure travel doesn’t stop due to a high volume of cars all trying to merge onto I-70 at the same time.
Although the new strategies aren’t helping the traffic buildup in Summit County towns, Rice has seen improvement in travel times since the infamous Feb. 9 incident.
On that night, 40 cars and 14 tractor trailers spun out before making it to the tunnel, which contributed to the four-hour travel time from Silverthorne to the Eisenhower Tunnel.
A week later, on Feb. 16, and under similar road and traffic conditions, CDOT officials initiated the new strategies, including the deployment of traffic escorts. On that day, only five cars and one tractor-trailer spun out heading up to the tunnel, Rice said, and traffic delays were reduced to 31 minutes. However, motorists did have to endure about 90 minutes of traffic holds that backed traffic up into local towns.
Although Silverthorne Police Chief Mark Hanschmidt applauded CDOT’s efforts, turning Highway 9 into a parking lot presents serious safety risks for local community members.
“Metering the way we’re doing it right now is backing traffic up in the towns, and we’ll have cars backed up all the way to Keystone,” Hanschmidt said. “If we need to get an ambulance or a fire truck to an emergency, it’s not happening.”
Rice said CDOT officials already are addressing the concern by staging plows in more strategic positions. That way they can clear the uphill grade to the tunnel and, possibly, reduce the amount of time traffic builds up in Dillon, Silverthorne and Keystone.
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