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50 years connecting the west and east: A history of Colorado's Eisenhower-Johnson Memorial Tunnel

Posted: 4:51 PM, Mar 07, 2023
Updated: 2023-03-08 13:27:15-05

Fifty years ago, a tunnel that had been bored into the Continental Divide in Colorado opened to the public, connecting the east and west in a new way.

The Eisenhower-Johnson Memorial Tunnel established a route for people to travel to Clear Creek County and Summit County, which divide the tunnel. Drivers previously had to head over Loveland Pass to reach the other side of the divide. The tunnel not only saved them the trip over the pass, but also 9.1 miles, according to the Colorado Department of Transportation (CDOT).

"It's a connector between the eastern part of the state and the western part of the state and the 50-year birthday is a big deal because that tunnel has significance not only for state transportation history, but also nationally, as part of the Interstate Highway System," said Lisa Schoch, cultural resources section manager and senior historian at CDOT headquarters.


She said as one of the CDOT historians, it's the biggest thing the department has ever built.

"You're at high elevation, building in a really pretty difficult and rigorous environment, right?" she said. "You're (at) 11,000 feet trying to mine this tunnel that's over a mile long through the Continental Divide, which is mostly granite."

    Today, more than 30 employees work at the tunnel performing duties that range from emergency response and ventilation work, to snow removal and operation surveillance.

    The Eisenhower Tunnel, which today transports only westbound travelers, opened on March 8, 1973 with two lanes of traffic moving in both directions. This came in the wake of five years of planning, designing and construction. The Johnson Tunnel, which is now home to the eastbound lanes, wouldn't open until Dec. 21, 1979. It was completed in four years.

    Fifty years later, the tunnels see an average of more than 36,000 vehicles each day, as of January 2023.

    Let's take a look at the history of the Eisenhower-Johnson Memorial Tunnel and its impact in Colorado and beyond.

    May 1943 | A pioneer bore was completed under Loveland Pass to see what sort of geologic conditions were under the ground. The Department of Highways advertised for bids on a vehicular tunnel at the site. But it only received one bid, which was not formally considered.

    1956 | Bids opened for two tunnel projects. One was for Straight Creek and the other was for Berthoud Pass. Only one bid was received for each. No contract was awarded.

    March 1960 | A report submitted to the Department of Highways from an engineering firm said Straight Creek was the best of eight possible interstate routes between Empire Junction and Dotsero. The report came from E. Lionel Pavlo in New York City.

    Oct. 3, 1967 | The call for bids for the Eisenhower Tunnel — which was called the Straight Creek Tunnel at the time — opened. It was the fourth bid request for a highway tunnel under the Continental Divide. The prime contractor chosen was the four-company joint venture Straight Creek Constructors, which was responsible for about 7/10 of the project. Their bid of $54 million was accepted. The Division of Highway had an estimate of $42 million.

    March 15, 1968 | Construction on the westbound bore began. This would later become the Eisenhower Tunnel.

    April 7, 1972 | The tunnel was officially named after the late President Dwight D. Eisenhower.

    July 1972 | The Colorado Division of Highways began to develop a design for an eastbound tunnel, which would later go on to be named the Johnson Tunnel.

    November 1972 | The sexual discrimination lawsuit that Janet Bonnema, a female technician who wanted to work on the tunnel, filed earlier in the year was settled and did not go to court. She won that battle in November 1972, when Colorado voters decided to amend the state constitution to guarantee equal rights for women. Afterward, she went to work in the tunnel, much to the dismay of many male coworkers.

    March 8, 1973 | The Eisenhower Memorial Tunnel was dedicated and opened to the public. Federal funds covered about 92% of the $108 million cost.

    March 19, 1974 | Almost 3 million cars had used the Eisenhower Memorial Tunnel in its first year open, as reported by the Golden Transcript. This was above what was expected. Daily amounts were roughly 8,1000.

    April 19, 1974 | An investigation of carbon monoxide levels in the Eisenhower Memorial Tunnel prompted the Colorado Department of Health to ask the transportation department to improve the tunnel's ventilation system, as reported by The Vail Trail.

    May 1, 1975 | The Division of Highways began to advertise for bids to be opened the following June on the first of five stage construction contracts for the second bore. They included:

    1. Mechanical/electrical work to cover the south tunnel ventilation fans
    2. Fan control system
    3. Standby generator at the west portal
    4. Propane standby systems at both portals
    5. East portal passenger elevator

    Aug. 11, 1975 | The contract for the Johnson Tunnel was awarded to Kiewit/Brown and Root at the bid price of $102.8 million. The Division of Highway had estimated the project to total $110 million.

    Aug. 18, 1975 | Construction on the Johnson Bore began.

    November 1975 | Actual mining started on the Johnson Bore.

    April 2, 1976 | According to The Vail Trail, on its third birthday, the Eisenhower Memorial Tunnel had seen almost 10 million vehicles.

    January 1978 | Colorado's 51st General Assembly passed a resolution requesting that the Highway Commission name the second bore after Edwin C. Johnson, who was a Colorado governor and US senator. Johnson was a big supporter of an interstate highway across Colorado.

    Dec. 21, 1979 | The Johnson Tunnel opened. It was named after the former Gov. Johnson. During both bores' construction, about one million cubic yards of rock, debris and other material was cleared from each one. In total, seven men had died working on the two tunnels.

    December 1979 | When the tunnel opened, it wasn't only the highest vehicular tunnel in the country, but also the highest in the world (though this claim to fame no longer stands).

    Jan. 9, 1988 | A state task force began to study a proposal to convert the two-lane traffic tunnels to three lanes in each bore of the tunnels to reduce traffic congestion, the Aspen Daily News reported.

    March 8, 2023 | The Eisenhower Tunnel is celebrating "Connecting Colorado for 50 years" with the 50th anniversary of the Eisenhower Tunnel opening to the public. Looking ahead, there are multiple repairs and upgrades expected at the Eisenhower Johnson Memorial Tunnel in 2023 and 2024.