Used to be on Construction and Design Page

Design and Construction

The design concept developed during the National Environmental Policy Act phase and documented in the Environmental Assessment (EA) has been refined through a Construction Manager/General Contractor (CMGC) process. The project features noted above remain the same. The refined design changes have to do with re-aligning parts of I-70 and the frontage roads due to geographic constraints in the canyon and construction safety/accessibility. 

View the latest I-70 Floyd Hill design model here. If you click the link and see "Page Not Found", refresh your browser to start the interactive model.

The Project has been designed and will be constructed in three main geographic sections shown on the map below. The design and construction schedules, features, and notable design changes for each of these sections are described below the map. Construction is anticipated to begin in 2023 and be completed in 2028.

I-70 Floyd Hill Project Location map broken into east, central, and west sections

East Section (blue on the map) from County Road 65 to the bottom of Floyd Hill (near Johnson's Gulch)

Final Design: April 2023

Expected Construction Start Date: June 2023 (first of three sections to start construction)

Main Features:

  • Construct a third travel lane on westbound I-70 from the top of Floyd Hill to connect with the existing Westbound Mountain Express Lane (which currently starts at the Veterans Memorial Tunnels). The new lane will be a tolled Express Lane; the two existing General Purpose Lanes will continue to be available for those that do not choose to use the Express Lane.
  • Install wildlife fencing between Exit 247 and Soda Creek Road (east of Exit 248).
  • Construct an eastbound I-70 climbing lane for heavy commercial or slow-moving vehicles from a new US 6 ramp to eastbound I-70 from the bottom of Floyd Hill to the Hyland Hills/Floyd Hill interchange at Homestead Road at the top of Floyd Hill.

Notable Design Changes from EA Concept: None.

Central Section (orange on the map) from the Middle of Floyd Hill to Hidden Valley/Central City Parkway

Final Design: July 2024

Expected Construction Start Date: Fall 2024 (last of three sections to start construction)

Main Features:

  • Continue the third travel lane (Express Lane) on westbound I-70
  • Replace the bridges at the bottom of Floyd Hill with new structures and alignment to improve safety and sight distance
  • Flatten curves on I-70 to improve safety and achieve a 55 MPH design speed
  • Construct a new frontage road connection between the US 6 and Hidden Valley/Central City Parkway interchanges
  • Relocate the US 6/I-70 on- and off-ramps to the Hidden Valley/Central City Parkway interchange (via the new frontage road connection)
  • Construct a new on-ramp to eastbound I-70 from the bottom of Floyd Hill/US 6, which will connect to the new eastbound I-70 climbing lane for heavy commercial or slow-moving vehicles
  • Reconstruct the Clear Creek Greenway trail from the bottom of Floyd Hill to County Road 314
  • Realign and restore portions of Clear Creek

Notable Design Changes from EA Concept (from east to west):

  • Shifts I-70 westbound alignment north to bottom of existing slope (closer to US 40 and Clear Creek) to improve construction access
  • Relocates US 6 access onto westbound I-70 to the Hidden Valley/Central City Parkway interchange
  • Realigns eastbound and westbound elevated portions of I-70 over Clear Creek Canyon to separate alignments with a terraced hillside cut, rather than parallel viaducts with a larger hillside cut. Eastbound I-70 is still elevated but lower than the EA concept and returns to existing grade near US 6
  • Realigns an approximately 1,600-foot section of Clear Creek south near the Hidden Valley/Central City Parkway interchange (instead of a similar creek realignment in the West Section).

West Section (purple on the map) from Hidden Valley Interchange to Idaho Springs Exit 241

Final Design: October 2023

Expected Construction Start Date: Fall 2023 (second of three sections to start construction)

Main features:

  • Continue the third travel lane on westbound I-70 through the Veterans Memorial Tunnels to Exit 241
  • Flatten I-70 curves to improve safety and achieve a 55 MPH design speed
  • Rebuild the bridges over Clear Creek, just west of Hidden Valley
  • Resurface/reconstruct the Clear Creek Greenway trail from the Hidden Valley interchange to the Veterans Memorial Tunnels
  • Install a noise wall east of Idaho Springs Exit 241

Notable design changes from EA concept:

  • Concentrates widening for the new westbound travel lane on north side of Clear Creek Canyon. More rock excavation will happen next to westbound I-70, but no rock excavation will happen on south side of Clear Creek Canyon.
  • Avoids impacts to County Road 314, which will remain open during construction, and Clear Creek.
  • New impacts to an archaeological site, which will require a treatment plan and
    memorandum of agreement with the State Historic Preservation Office.