Colorado Department of Transportation halts plans for major improvements at Interstate 70’s Exit 205. Here’s why.

Nicole Miller/Summit Daily News
Traffic issues between Dillon and Silverthorne ignited a push from Summit County residents in recent years for improvements on two Interstate 70 exits: Exit 205 in between Dillon and Silverthorne and Frisco’s Exit 203.
The Colorado Department of Transportation worked with local officials for years to devise a plan, but Exit 205’s proposal has been rescinded, according to information shared at an open house on Nov. 19.
An executive summary for the Colorado Highway 9 and U.S. Highway 6 mobility study stated that CDOT decided to “specifically exclude capacity improvements” since the physical impacts would be “too great” and highlighted “loss of developed properties” as one of the impacts.
A “diverging diamond” interchange — a traffic slowing mechanism which diverts cars in different directions without forcing them to wait at a stoplight — was contemplated for Exit 205. It would have created a six-lane corridor on Colorado Highway 9 and U.S. Highway 6, which CDOT cited as its reason to nix the plans.
“The Project Leadership Team considered this option early on, and all stakeholders agreed it would harm the community’s and the study area’s core values,” CDOT Interstate 70 Mountain Corridor Communications Manager Austyn Dineen said.
The corridor has already been “developed up to the (right-of-way) line (e.g. with buildings close to the highway in Silverthorne), making it cost-prohibitive to add two new through-lanes due to the need to acquire more (right-of-way,)” Dineen said.
She said instead the focus will be placed on improving efficiency within the current system by refining signal timing, adding turn lanes to major roadways connecting to the corridor, such as Stephens Way, and managing turning movements at key intersections to improve through-traffic flow.

Dillon Mayor Carolyn Skowyra said Dillon Town Council hasn’t discussed the change, but in her opinion it was a pricey project that seemed like a long shot anyways.
“While Silverthorne would like to see improvements made to the (Exit) 205 Interchange as traffic and population grow across the state of Colorado, focusing on responsive traffic signal timing and access management along the corridor will help ease traffic congestion on our local roadways,” communications director Kristina Nayden said via email.
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Amid planning improvements to Interstate 70 auxiliary lanes and exits, CDOT voiced essentially from the start that Exit 203 improvements would take priority over changes to Exit 205. Previously, county officials also shared the sentiment that Exit 203’s issues were far worse than Exit 205’s and needed to be addressed more immediately, but as time went on they realized the exit had larger traffic issues than originally anticipated. Things came to a head during this past Martin Luther King Jr. Day weekend when traffic bottlenecked near Exit 205, as that area of Silverthorne serves as a converging point for people changing roadways coming from ski areas across the High Country.
Other community concerns regarding Exit 205 stemmed from a statewide traffic growth model which demonstrated CDOT is anticipating traffic through the corridor will increase 45% by 2045.
CDOT conducted an 18-month study on Colorado Highway 9 and U.S. Route 6 which considered traffic patterns today and those 20 years from now and subsequently recommended projects and improvements. Initial cost estimates for around 20 potential projects state that it will cost upwards of $70 million, according to the study’s executive summary.
Notable potential projects include realigning Stephens Way to the east and Little Beaver Trail to the west to create a single signaled, four-legged intersection; a roundabout from Wildernest Road to Stephens Way and one at the intersection of Dillon Ridge Road and U.S. Route 6, alongside a pedestrian bridge on Lake Dillon Drive going over U.S. Route 6.
CDOT officials said at the Nov. 19 open house projects will be knocked off the list based on when funding is acquired for them.

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