

March 8 marks 50 years since a 1.7-mile tunnel opened and connected Colorado east to west beneath the Continental Divide β a feat so spectacular it's easy to forget what it took to become a reality.
Driving the news: The first tunnel, now the westbound side and named for former President Eisenhower, opened March 8, 1973, amid huge fanfare that drew hundreds to the ceremony.
- The second bore, named for former Colorado governor and U.S. Senator Edwin Johnson and now the eastbound route, came six and a half years later.
- Before then, travelers took dangerous turns on U.S. 6 over Loveland Pass or U.S. 40 over Berthoud Pass to reach the Western Slope.
What they're saying: "There was a lot of blood, sweat and tears to get that tunnel open," Tamara Rollison at the Colorado Department of Transportation tells Axios Denver.
Why it matters: Now known as the Eisenhower-Johnson Memorial Tunnel, the Interstate 70 route serves as the lifeblood of the state's economy β and a chokepoint that makes it the bane of every traveler.
- Since it opened, roughly 434 million vehicles have traveled through the tunnels β an average of 35,427 a day in 2022.
- And even in 2007, its economic impact approached $1 billion.
Flashback: The project actually started 50 years prior to its completion with a "pioneer" tunnel under Loveland pass in 1941 and an exploratory drilling bore that began at the current site in 1963.
What's next: The tunnel is aging and requires $150 million in infrastructure upgrades, mostly in modernizing operations motorists don't see, state transportation officials say. So far, only $50 million has been allocated.
- The most visible project is the building of a massive new operations center on the west side of the tunnel.
Photo gallery: The history of the Eisenhower tunnel at 50 years

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