The Eisenhower Tunnel Turns 40 Today

March 8, 2013 - Central Eastern Colorado/CDOT Region 1 - DENVER– Today, March 8, 2013, marks the 40th anniversary of the dedication and opening of the westbound bore or the Eisenhower Tunnel at the Eisenhower/Johnson Memorial Tunnel west of Denver, which is the highest vehicle tunnel in the world at 11,155 feet.

The Eisenhower Tunnel was the first of two bores to open to help facilitate easier transportation between Colorado’s east and west slopes.

Actual construction of the 1.7-mile tunnel, 60 miles west of Denver, began on March 15, 1968. When the first bore was completed in 1973, it eliminated the 9.5-mile drive on U.S. 6 over Loveland Pass. Traffic continued in a two-lane configuration until the second bore (Johnson Tunnel), serving eastbound traffic, was completed on December 23, 1979.

The Eisenhower Tunnel proved popular with motorists who previously had utilized Loveland Pass on U.S. Hwy. 6 or Berthoud Pass on U.S. 40 to cross the Continental Divide west of Denver.  Within five months of the tunnel opening, more than 1 million vehicles had passed through.  Today, the total numbers of vehicles through the Eisenhower Tunnel and its adjacent twin, the Edwin C. Johnson Memorial Tunnel, has exceeded 310 million vehicles and most paramount, without a fatal accident.

“The Eisenhower Tunnel ushered in a new era of accessibility between the two sides of Colorado and changed the way we perceive Colorado, uniting the east and west slopes with a new spirit of common purpose,” said Colorado Department of Transportation (CDOT) Executive Director Don Hunt.  “The tunnels provided reliable customer access that helped lead to development of international-level ski resorts at Keystone, Copper Mountain, Vail, and Beaver Creek, plus major expansion at Breckenridge.  The tunnels’ value in aiding interstate and intrastate commerce through Colorado, as well as economic development, is nearly incalculable.”

CDOT operates the Eisenhower-Johnson Tunnels complex utilizing a group of approximately 50 maintenance professionals who manage a water treatment and sewage facility, monitor all vehicles through the tunnels every hour of every day, perform regular maintenance duties on the tunnels themselves and all of the fans, ducts, and electronics required, and respond to any emergencies that may occur, including an average of 200 stalled vehicles and five vehicle fires per year.

CDOT Region 1 Transportation Director, Tony DeVito, said he hopes Colorado citizens will think more about the tunnels and their value to Colorado during this anniversary year.  “We’ve become used to the tunnels and we don’t give them much thought,” he said.  “My hat is off to all of the designers, engineers, miners, contractors, and workers who built the tunnels and their support complexes in the first place, and to all of the CDOT employees who work so hard every day to ensure that everything at the tunnels is safe and that traffic is moving efficiently.  Those folks can’t control the weather or driver behavior, but they can and do control just about every other aspect of operations there.  Motorists can feel good that our tunnels employees are there watching out for them every day of the year.”

For more information about the Eisenhower/Johnson Memorial Tunnel, visit

Key Eisenhower Tunnel Facts

  • Cost:  $116.9 million westbound; $144.9 million eastbound (In today’s dollars, the cost to build one bore would be $1 to $1.5 billion)
  • Grade: 1.64 %
  • Travel width: 26 feet (two 13’ lanes) each direction
  • Ventilation fans: 16 westbound.  Supply fans (6 active, 2 standby) provide up to 533,000 cubic feet of fresh air per minute.  Exhaust fans (6 active, 2 standby) may pull 542,000 cubic feet per minute.  12 eastbound (downhill grade).  3 exhaust fans and 3 supply fans at each portal.  System is divided at mid-mountain so that half of each tunnel bore is ventilated from each portal.

Each fan is 10 feet, 6 inches in diameter.

  • Highest 24 hour traffic count: 50,918 on August 2, 2009
  • Highest 1 hour traffic count: 4,708 on March 9, 2007
  • Highest 3-day weekend count: 148,300 on August 7-9, 2009