I-70 Floyd Hill to Veterans Memorial Tunnels Improvements

Environmental Assessment Phase

Environmental Assessment Complete

On Aug. 2, 2021, CDOT released an Environmental Assessment detailing our preferred plan for highway and other improvements between Floyd Hill and east Idaho Springs. Read the Environmental Assessment and navigate the self-guided virtual public engagement website for more information.

Project Facts

  • Cost: $600-$700 million
  • Location: On westbound Interstate 70 from east of the Floyd Hill/Beaver Brook Exit (248) through the Veterans Memorial Tunnels to Colorado Blvd./Idaho Springs Exit (241)
  • Contractor(s): TBD.

In summer 2017, CDOT and the Federal Highway Administration (FHWA) began phase two of studying and planning improvements on westbound I-70 from Floyd Hill to the Veterans Memorial Tunnels. Among the improvements being considered: increasing travel-time reliability, increasing capacity on the highway, replacing a deficient bridge and improving the geometric design of the interstate.

This stretch of I-70 is one of the most congested locations on the westbound I-70 mountain corridor. High-traffic volume on I-70 west of Denver has led to ever-increasing periods of slow traffic, which, at times, approaches a gridlock situation. This area also is heavily impacted by adverse weather conditions.

I-70 Floyd Hill to Veteran Memorial Tunnels Improvements project limits study area map

 Alternatives Considered

The I-70 Floyd Hill to Veterans Memorial Tunnel Project would improve I-70 from Floyd Hill (west of Evergreen) through the Veterans Memorial Tunnels on the eastern edge of Idaho Springs.

The major elements of the project are:

  • Adding a third westbound travel lane to the two-lane section of I-70 from the current three-lane to two-lane drop (approximately MP 246) through the Veterans Memorial Tunnels the new lane would be an Express Lane
  • Constructing a new frontage road between US 6 and the Hidden Valley/Central City Interchange
  • Improving interchanges and intersections throughout the Project area
  • Improving design speeds and stopping sight distance on horizontal curves
  • Adding an auxiliary lane to I-70 in the eastbound (uphill) direction of Floyd Hill between the US 6 interchange and the Hyland Hills/Floyd Hill interchange 
  • Improving the multimodal trail (Clear Creek Greenway) between US 6 and the Veterans Memorial Tunnels
  • Reducing animal-vehicle conflicts and improving wildlife connectivity with new and/or improved wildlife overpasses or underpasses
  • Providing two permanent air quality monitors at Floyd Hill and Idaho Springs to collect data on local air quality conditions and trends
  • Coordinating rural broadband access with local communities, including providing access to existing/planned conduits and fiber in the interstate right of way

Two alternatives are under consideration for adding the third lane of capacity along westbound I-70 between US 6 and the Hidden Valley/Central City Interchange:

  1. The canyon viaduct alternative (preferred) would construct a viaduct structure and elevate both the eastbound and westbound lanes of I-70 through the Clear Creek Canyon. The existing I-70 highway under the new bridges would be used for the frontage road and Greenway. The video below provides more detail about the preferred alternative.

  2. The tunnel alternative would construct a tunnel that would carry three lanes in the westbound direction of I-70. Eastbound I-70 would be realigned on the exiting highway footprint to flatten curves. This alternative also includes two options for the alignment of the new frontage road on either the north or south side of Clear Creek. Two design options were considered for the frontage road alignment under the tunnel alternative. The North Frontage Road option would locate the new frontage road on the north side of Clear Creek. The South Frontage Road Option would locate the frontage road on the south side of the creek. The video below provides more detail about the tunnel alternative.

    • The EA also evaluated the No Action Alternative, which would replace the failing bridge at the bottom of Floyd Hill (near the US 6 junction with I-70) but not add any roadway capacity or other improvements.