Hanging Lake Tunnel

Hanging Lake Tunnel graphic with photo of traffic on the roadway entering the tunnel

About the Tunnel in Glenwood Canyon

Hanging Lake Tunnel view from underneath the road looking at the eastbound tunnel entranceThe Hanging Lake Tunnel (HLT) consists of a pair of 4,000-foot tunnels on I- 70 in Glenwood Canyon. Completed in 1992, the tunnel was part of a major infrastructure project to build a safe, efficient highway through one of Colorado’s most rugged and environmentally sensitive regions.

A vital link for I-70 travel and traffic safety, the Hanging Lake Tunnel houses one of four CDOT operations centers. This facility provides live traffic monitoring, emergency response coordination, and communication services for much of western Colorado.

Engineered with advanced tunneling techniques and designed to blend into the surrounding landscape, the tunnel is a model of sustainable highway construction. It demonstrates how modern transportation infrastructure can coexist with natural beauty. The Hanging Lake Tunnel helps maintain safe mountain travel on I-70 while preserving the scenic environment of Glenwood Canyon, one of Colorado’s most iconic natural corridors.

Hanging Lake Tunnel Operations Center employee looking at his computer and monitoring cameras.HLT Operations

HLT is located in CDOT's Denver Northwest region (Region 3, in Maintenance Section 2). All tunnel employees are trained firefighters, and the tunnel has its own fire truck and tow truck so Co-crews can respond to emergencies and clear crashes in or near the tunnel. Crew members are also responsible for monitoring the air quality levels inside the tunnel and controlling the ventilation fans to ensure the carbon monoxide levels are kept low. 

HLT Traffic Incident Management

How does CDOT keep Colorado's highways and roads open? Well, it takes an entire team. Whether it's a minor fender-bender during the workday commute or responding to wildfires and mudslides in mountains and canyons, CDOT's traffic incident response teams work together to keep traffic moving. Our business is reducing travel delays and collaborating with emergency responders to improve your drive. Watch the video below to learn more and see our crews in action.

HLT Maintainers

More than 30 full-time employees work at HLT. Job duties range from:

  • 24/7 operations surveillance
  • Emergency response
  • Tunnel washing
  • Ventilation maintenance
  • Tunnel sweeping
  • Snow removal
  • Heavy equipment maintenance
  • Water treatment

HLT Interesting Facts

  • Construction began in 1980 and concluded in 1992
  • The $490 million project that transformed I‑70 through the 12-mile Glenwood Canyon corridor
  • The HLT Operations Center includes a live camera network with more than 120 to 126 cameras monitoring I‑70 through Glenwood Canyon
  • Emergency response capabilities includes fire trucks, snowplows, tow trucks and crash attenuators
  • Regional dispatch covers several highways across 15 counties in Western Colorado