I-70 Silverthorne/Dillon Interchange Study

Once funding is available for an updated review and improvements to the I-70 Silverthorne/Dillon Interchange (Exit 205), CDOT will refresh the Planning and Environmental Linkages (PEL) Study and design improvements. An updated PEL will be necessary to ensure CDOT is using the most recent data before designing improvements.

As of December 2020, CDOT continues to pursue improvements to the I-70 corridor in Summit County, with the I-70 EB Auxiliary Lane Project from Frisco to Silverthorne, the I-70 Exit 203 Interchange Improvements Study in Frisco and the I-70 Dillon Structure Replacement at Mile Point 211. Work is also underway for the last section of improvements on Colorado Highway 9 between Breckenridge and Frisco, known as the Gap Project.

About the Project

The CO 9/US 6 Improvement Project, formerly known as the I-70 Silverthorne/Dillon Interchange Project, at the I-70 Silverthorne/Dillon Interchange involves evaluating possible improvements to Colorado State Highway 9, US 6 at Exit 205 in Summit County.

The project includes:

  • Changing the interchange design
  • Improving the westbound I-70 on ramp
  • Improving the CO 9/Wildernest intersection
  • Construction of a continuous eastbound auxiliary lane from the Frisco interchange to the Silverthorne/Dillon interchange 

The recommended improvements would be constructed in phases as funding becomes available. The new interchange design will be a Diverging Diamond.

CDOT will seek funding for the next steps in the process, including compliance with the National Environmental Policy Act (NEPA), obtaining environmental permits, and demonstrating compliance with various environmental laws and regulations. These steps and a formal approval process would be followed by final design and construction.