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Eisenhower Tunnel celebration
Driving 1970s cars through the Eisenhower Tunnel was part of the 50th anniversary event Wednesday. (Hugh Carey, The Colorado Sun)

Thousands of vehicles travel through Eisenhower Tunnel on Interstate 70 each day. But on Wednesday, for a brief moment, the traffic stopped to let just three pass: a 1970 Plymouth Fury police cruiser, an antique fire truck, and a MG sports car of a similar vintage.

The procession was part of the Colorado Department of Transportation’s celebration of the Eisenhower Tunnel’s 50th anniversary. 

Since the tunnel opened on March 8, 1973, millions of cars have crossed under the Continental Divide through the passage. When the ribbon was cut on the tunnel, 44.3 feet high and 47.5 feet wide, the $110 million price tag was the most expensive highway project ever embarked on by the U.S. government. Three men died during the five years of construction. 

CDOT Executive Director Shoshana Lew said the Eisenhower Tunnel provided a safe, accessible alternative to driving on riskier mountain passes and changed the character of the state forever.

“For the last five decades, 50 years, the Eisenhower Tunnel has served as a great connector, tying east and west together in Colorado,” she said, speaking to a small crowd at the tunnel’s eastern opening. “It has provided a critical life saving link, moving goods and services, and helped to mark Colorado as a world class mountain destination.”

Live video monitors of Interstate 70 fill the walls of the control room inside the Eisenhower Tunnel on Wednesday. (Hugh Carey, The Colorado Sun)

Many travelers through the tunnel might not realize that it’s more than just a simple passageway through the mountains. Managing the 1.7-mile passage requires a control room, where operators monitor the flow of traffic on walls of screens, a generator room, a sprinkler system, a water treatment system and even a fire truck. 

Jessica Myklebust, CDOT’s Denver metro region director, said the look of the tunnel, through which 524,151 vehicles passed last month, can be deceiving.

“It is an around-the-clock operation with men and women with special technical expertise who keep the tunnel open and safe,” she said. “Since the tunnel opened in 1973, we have not had one fatality in either of the tunnels.”

At 50, there’s a certain historical charm to the look and feel of Eisenhower Tunnel, but it’s also in need of regular maintenance, and maybe a makeover. Much of the equipment inside the tunnel system — like its 600-horsepower industrial fans (all 28 of them) capable of producing hurricane-force winds to clear noxious fumes — is original, or at least old. 

As part of CDOT’s 10 Year Plan for infrastructure investment, the Eisenhower Tunnel, and its eastbound partner, the slightly younger Johnson Tunnel, will have a $150 million update completed by 2024. Some minor work already has been done, but more robust renovation projects, like an automatic de-icing system, are slated to begin soon, CDOT spokesperson Presley Fowler said. However, it’ll still be the tunnel Colorado’s loved for 50 years, she said.


“We don’t want to change the look and the feel of the tunnel,” she said. “That’s really been an important aspect while planning these infrastructure upgrades and repairs — making sure to honor the history.”

For decades, the tunnel has made traveling through the mountains much safer and efficient, CDOT spokeswoman Tamara Rollison said. In her view, Colorado wouldn’t be the state it is today without this critical link through its alpine reaches.

“It’s hard for me to say what it’s going to be like 50 years from now for the tunnel, but it will be here continuing to serve the state, I’m sure of that,” Rollison said. “And it will continue to be a vital connection for years to come.”

While there were empty lanes Wednesday inside the Eisenhower Tunnel, nearly 13 million vehicles passed through the tunnels last year in both directions, according to CDOT. (Hugh Carey, The Colorado Sun)

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