The weak beams from our cellphone flashlights do little to dispel the darkness that stretches uninterrupted for 1.7 miles. “I don’t go in here alone,” says Paul Fox, Colorado Department of Transportation (CDOT) region one tunnel program manager and my guide to the Eisenhower-Johnson Memorial Tunnels (EJMT) on this warm March day. He doesn’t seem to be joking. With no traffic flowing through the tunnels, it’s completely dark and eerily silent. I’m not sure why Fox didn’t bring real flashlights, and although we’re only a few hundred yards into one of the plenums—the access corridors that live above and stretch the length of the two vehicle tunnels—if our phones were to die, I doubt we’d make it back to the East Portal before sensory deprivation hallucinations set in.

Normally, there’d be ample light in the plenum, but the tunnel complex is undergoing a $71 million upgrade and repair project, the biggest since it was completed in the 1970s. Back at the East Portal structure, the EJMT’s head electrician, Richard Roybal, and his crew are paired up with a team of preventive maintenance technicians to install an uninterruptible power supply system, and they’ve shut off the electricity the same way you’d flip your home’s circuit breaker before installing a light fixture. The outage—and the traffic jam it creates—shouldn’t last more than 30 minutes, but Fox is eager to show me the plenum to illustrate a point: The tunnels aren’t some static structure. They’re alive.

“This mountain changes every day. Everything changes year to year, season to season,” says Fox, a stout man with a trim goatee and an easy laugh. “But you can’t change it in any way. You just have to work with it.”

Then, as if to prove him right, a CDOT communications manager calls Fox, but the cell reception is so poor the connection doesn’t go through. At nearly the same time, Stacia Sellers, another CDOT communications manager who’s organized this excursion, gets a text from Denver7 News asking why the tunnels are shut down. Short traffic holds such as the one they’ve enacted today are common enough that Fox usually doesn’t even notify his bosses about them, much less the media. To get a text now probably means something has gone wrong at the East Portal. We won’t know until we get back to the light.

Man standing behind silver pipes
Paul Fox, the CDOT deputy superintendent in charge of the Eisenhower-Johnson Memorial Tunnels, stands in front of one of 16 multistory fans that can be used to expel carbon monoxide and other noxious gasses from the tunnels and help contain any vehicle fires. Photo by Daniel J. Brenner

The attention Fox is about to get is a perfect illustration of what researchers refer to as the invisibility of infrastructure. It’s only when infrastructure breaks, whether it’s a closed tunnel, a broken cell phone tower, or a delayed train, that the public seems to notice it exists. “Unfortunately, we usually take for granted when things work, and we don’t value maintenance as much as we probably should,” says Cristina Torres-Machi, an assistant professor of civil engineering at the University of Colorado Boulder. “But we also do that in our daily life. We only remember how good the dishwasher is when it’s not working.”

With America’s golden era of infrastructure construction behind us—a period which arguably began with New Deal public works projects in the 1930s and ended with the completion of President Dwight D. Eisenhower’s Interstate Highway System in 1992 just down the road in Glenwood Canyon—there’s been a shift in both academic thought and in practice at various levels of government to elevate infrastructure maintenance in the national consciousness, lest it arrive unbidden. In the Centennial State, there’s no better embodiment of this shift than the EJMT. It cost $262 million to build both bores between 1968 and 1979, or the equivalent of about $1.2 billion today. But calculating the cost of adding a third tunnel bore—something CDOT has identified as essential for alleviating congestion on the I-70 mountain corridor—isn’t as simple as adjusting for inflation. Modern environmental protections, safety standards, and construction techniques all drive up the costs of these massive projects, a serious problem considering the agency’s 2024–’25 budget is only $1.7 billion. When I ask how much a third bore would cost, Fox jokingly throws out a figure: $300 billion. Bob Fifer, CDOT’s deputy director of operations, echoes the sentiment.

“A third tunnel would be a major lift, a major cost escalation,” he says. “I can’t see that happening.”

The inability to green-light ambitious infrastructure projects is happening all over the country. Most of President Joe Biden’s lauded $1.2 trillion Infrastructure Investment and Jobs Act, for example, will go toward repairing or upgrading existing infrastructure instead of funding new projects on the scale of the EJMT. Even that $1.2 trillion is half of what the American Society of Civil Engineers estimates the United States would need to invest over the next decade to simply maintain its ports, electrical grids, bridges, and transportation networks in a “state of good repair.” “There is something kind of nostalgic [about the EJMT]—that they could gather the will and the funding and the common commitment to build these kinds of incredible engineering marvels,” says Steven Jackson, a Cornell University professor whose areas of study include the maintenance of infrastructure systems. “There’s some question if we even remember how to do that or know how to do it together anymore.”

Jackson agrees with Fox and Fifer that escalating expenses are a major reason grand public works like the EJMT aren’t often attempted anymore, but he also believes there could be a deeper, societal issue at play. “[Back then], there was a notion of government being a conduit for collective purpose that could gather and channel resources for projects like the tunnels, but it’s harder to see in our current moment,” he says. “The tunnels almost feel like relics of a bygone bipartisan world.”

All of this leaves CDOT with one option: make do with what it already has. For years, though, it wasn’t even really able to do that.

2 men and machinery
Laborers with ECI Site Construction Management Ethan Moshier and Ethan Pearson use machinery to fill cavities in mountain rock with concrete to prevent mineral water from leaking through the plenum and into the tunnel. Photo by Daniel J. Brenner

In 2021, CDOT had $150 million worth of repairs it needed to make on the tunnel complex, an impossible task given CDOT’s annual $10 million repair budget for the 22 tunnels it manages. “It just keeps getting exponentially worse,” then EJMT resident engineer Neal Retzer told the Denver Post at the time. In response, the state Legislature tapped into the $188 million set aside by 2017’s Sustainability of Rural Colorado Act and passed Senate Bill 21-260 to create a new, long-term source of funding for CDOT by reorganizing the existing Bridge Enterprise into the Statewide Bridge and Tunnel Enterprise and expanding its funding through fees, such as one on retail deliveries like takeout orders.

The American Society of Civil Engineers has found that failing to maintain our infrastructure could cost the country’s GDP $10 trillion over the next two decades. “The rule of thumb is that it usually costs 10 times more to rehabilitate [infrastructure] when the condition is very poor compared to preservation,” says CU Boulder’s Torres-Machi. CDOT has done its own estimates and found that every $4 spent on proactive resilience measures saves $25 on future repairs. Those numbers are compelling; however, it is important to keep in mind that for every hour the tunnels are closed to traffic for repairs, nearby mountain towns lose $1.6 million in economic impact.

The ongoing $71 million project includes: $8.5 million to install electronic messaging signs and replace the aging analog cameras used to monitor traffic; $8 million to repair guardrails, install a retaining wall, and perform miscellaneous repairs around the tunnel complex itself; and $28 million to revamp the tunnels’ plumbing to prevent pipes from freezing and to improve first responders’ access to fire hose connections. Roughly $25 million has been earmarked to battle the Ice Monster.

If you’ve ever driven through the tunnels in the winter, you’ve likely seen the Ice Monster. This not-so-mythical beast usually forms just inside the tunnel mouths when water seeps through the mountain rock and permeates the EJMT’s broken waterproof liners, where it collects in the plenums, freezes, and slowly gathers on the roadways below, forming Lilliputian glaciers. Every time maintenance staff patches a hole to stop a leak, the water finds another way in.

Left unchecked, the Ice Monster would block tunnel traffic in a matter of hours, so Fox’s staff is constantly scraping it off the asphalt with heavy machinery. If the contractor CDOT has hired for the project can just shepherd the leak away from the tunnel entrances and into the interior, where the temperature is warm enough that the water won’t freeze, Fox will be happy. But nothing is that simple. Before repairs could begin on the liner, for example, the contractor had to suspend a walkway from each plenum’s arched concrete ceiling because the floor—which is also the roof of the vehicle tunnel below—isn’t strong enough to support the equipment the job requires.

The plenum’s original floor isn’t strong enough to support the Ice Monster, either. During our tour, Fox stops us in the dark and swings his phone’s flashlight over the edge of the ad hoc gangplank. Caught in the beam, a pseudo-stalagmite reaches up from the floor for a few feet before latching onto the wall like ivy. The high-alpine water is so pure that the pillar is perfectly clear. You could make craft cocktail ice cubes with it.

Below the frozen pillar, more ice spreads in all directions around a drain that leads down into the vehicle tunnel. To keep it clear, and the ice to a minimum, there is a mobile heater nearby. “We shut it off yesterday, and the drain’s already frozen over,” Fox says as he inspects the area. When it’s running, though, the heater seems to do the trick so at least the floor won’t buckle—or worse, collapse into the tunnel below.

man in front of video screens
Bob Fifer, CDOT’s deputy director of operations, stands in front of the two-story-tall digital video screen in the new operations center. Photo by Daniel J. Brenner

Earlier in January, Fifer is like a proud parent as he shows off CDOT’s new tunnel command center, located inside a previously mothballed engineering building outside the West Portal. The renovation is part of a separate but concurrent project to improve traffic flow and working conditions at the complex. Although the building isn’t open yet, it already sports beds with hospital-style curtains, showers, and a break room for when the staff pulls 15-hour shifts to keep the tunnels open during snowstorms. One room over, the new command center has a two-story-tall video screen that fills an entire wall.

When the building officially opens this fall, the staff will use it to monitor new cameras for anything that could slow down traffic, including oversize loads, stuck cars, vehicle fires, and medical emergencies. They’ll also be able to reconfigure the screens on the fly so they can patch into emergency CDOT video calls during blizzards, watch weather radar, and scan traffic maps.

“We’re going from 20-year-old, fuzzy TVs to a system where we can look almost a mile away and read a license plate,” Fifer says. Visually, the entire building is a 180 from the current windowless command center located in the tunnels’ East Portal, where the exposed concrete, clunky physical switches, and analog dials give off Cold War missile bunker vibes. The new desks even have built-in hand warmers. “Our employees up here have a hard job,” Fifer says, “and we need to make sure we’re paying attention to their needs.”

The staff would have already finished moving into its new digs by the time of my January tour if it weren’t for one problem: They can’t figure out how to integrate the existing overheight detection system, a laser that’s triggered when a passing semitruck exceeds the tunnels’ height restrictions, with the new command center’s fiber-optic nervous system. “It’s so old,” Fifer says, “that it’s like trying to get something from a telephone in the 1960s onto the smartphone in your hand.”

Integrating the old and new isn’t just a physical problem; it’s a personnel one, too. Gone are the hammer slingers who were experts in hitting heavy things with other heavy things to get them to work again. At facilities as complex as this, everyone also needs to be digitally savvy, and that change comes with a new name. They’re no longer simply maintenance workers. They’re maintainers. “It is becoming more of a technical job,” Fox says. “Everybody’s born with a cell phone in their hand…so if we’re not willing to change, we’re going to be left behind.”

That moniker comes with better pay in recognition of the skills the tunnels require, something academics who study infrastructure maintenance have long advocated for. Studies have shown that maintenance work is often a form of invisible labor. The work is underappreciated and thus undervalued, undercompensated, and often performed by marginalized groups.

Today, the tunnels are fully staffed for the first time since at least 2018. “I was only running three people a shift for a while,” Fox says. “We were really close to where I had to put the ‘Closed’ sign up.” It was by convincing his superiors that the tunnels needed more maintainers lest all the repairs and upgrades they’ve funded “fall back into the hole as soon as they’re done” that Fox was able to start filling out his ranks. Now,
he has enough employees to staff a dozen or more for each shift.

Woman with orange truck measuring pole
Emily Johnson holds a tool used to measure the height of trucks driving through the tunnel. Photo by Daniel J. Brenner

One of those workers is Emily Johnson, a Georgetown resident who’s one of a few recent hires Fox has made from nearby ski resorts. Before working for CDOT, Johnson was tuning boards at Loveland Ski Area’s ski shop; now, she operates heavy equipment and gets a steady, year-round paycheck.

Although it’s mid-March, it’s warm enough that, despite the 11,013 feet of elevation, we can chat through the window of her work truck as she waits to pull over any vehicle that trips the over height detector before it can head into the tunnels. “It definitely beats sitting at a desk,” she says. When I ask her about the culture at her new workplace, she looks away for a moment as if deciding how best to phrase her response. “I will say I am the only female up here, and everyone has been awesome about that,” she says. “It’s the first time in a male-dominated industry where I haven’t had anyone talk down to me like I can’t do my job.”

It’s not until Fox and I return to the East Portal after our tour that we learn why his bosses were calling. The simple explanation is that the power wouldn’t come back on. The complex explanation is that the new supervisory control and data acquisition system acts, in part, as an interface between the tunnels’ decades-old electrical systems and the new ones CDOT has installed. Right now, it’s not interfacing.

This has happened before. In those cases, a straightforward reboot was all it took to get back online, but by the time we arrive, Roybal’s team has already tried that without success. Now, they’re diagnosing the problem by methodically flipping dozens of switches and breakers around the massive electrical room.

Despite the ticked-off motorists being held at the tunnel entrances because CDOT can’t risk letting them into a tar-black tunnel, everyone is calm. “There’s no need to freak out. The bosses do, but we don’t. During our car fires, during our accidents, it’s like, ‘It happened. We’re just here to clean it up. Just take it step by step,’  ” Fox says after getting off a call explaining the situation to headquarters in Denver. Then he points at Roybal and says, “But if he gets excited, then I’ll get excited.”

Man leaning on yellow railing
Richard Roybal stands in front of the new breaker system. Photo by Daniel J. Brenner

When the tunnels were short-staffed a few years ago, Fox was the one throwing breaker switches (the electricians have “Paul-proofed” the complex electrical system by placing color-coded magnets on the equipment to indicate which switches should be thrown in what order), but with pilot trucks beginning to shuttle drivers through the blacked-out tunnels at a safe pace, there’s little for him to do. So he continues our tour.

The East Portal’s interior is dominated by 16 multistory, apartment-size fans, which, together with their twins in the West Portal structure, expel carbon monoxide and other noxious gasses from the tunnels and help contain any vehicle fires. Tunnel fires are rare, but conflagrations happen about four times a week in the complex’s parking lots during the summer, when cars and trucks tend to overheat. The tunnels are so far from civilization, especially if traffic is backed up, that it might take an hour for help to arrive. That’s why EJMT staffers are cross-trained as firefighters and operate their own small fleet of fire trucks.

The ability to fight blazes is just one example of the wide skill set these workers need to have to—sometimes literally—keep the lights on. Because the tunnels are so old, replacement parts can be difficult to source. For a long time, tunnel staffers would build their own in the on-site machine shop to keep critical systems functioning, Fifer says.

Since Fox has taken over, however, he’s moved away from that practice. “We should have never been making our own,” he says. “We should always use something that we have a warranty for. Something that has a patent so it is proven to work.” This can make finding parts challenging, but it means things should break less frequently. That’s a good thing. When one piece of equipment malfunctions, it puts more strain on the other systems, which are equally as old and fragile.

Fox points out one of the massive fans linked to the south tunnel bore. “Eighteen months ago, right there, the motor bearings grenaded on us,” he says. “The bearing cap weighs 225 pounds, so when it exploded, it was all over the place. It was making so much noise because you’ve got a 600-horsepower motor that doesn’t care what’s in its way.” It took two weeks to repair the damage and would have taken longer if they hadn’t had a few spare bearings in storage. Luckily, the explosion didn’t affect the fan’s massive drive belt. They don’t make those anymore.

When I ask what would’ve happened if they couldn’t fix the fan, Fox shrugs. The original builders concreted over the doors to build the complex’s waste water treatment plant, leaving Fox with no way to get the old fans out or new fans in. It’s not the first time the builders have made life hard on those who came later. During construction, they’d frequently had to reroute water pipes and cables as they went, and those changes often went undocumented in the blueprints.

The discrepancies between the blueprints and reality can be so bad that in the May/June 2020 issue of TR News, the Transportation Research Board’s trade magazine, former EJMT chief engineer Stephen Harelson wrote that one unofficial job at the tunnels was “water witch,” a maintainer who used a bent welding stick turned divining rod to locate water lines hidden behind the concrete. Fox has never heard of this—maybe due to turnover, maybe because it’s a tall tale, or maybe because the staff is too afraid to loop in its by-the-book boss. “I’m a guy that follows policy and procedures,” he says, “but just because something was always done a certain way doesn’t mean it has to be done that way.”

There’s sure to be more evaluation of the maintenance processes. With no plans for replacing or rebuilding the tunnels, upkeep will only become trickier and more taxing as they age and Colorado’s population and tourism industry continue to grow. And as traffic congestion increases, there’s some question of what that means for the tunnels as the linchpin that helped unify Colorado by allowing for easy ground transportation across the Continental Divide. Eventually, we could see that geographic division become more prominent once again. “These are symptoms of success,” says Cornell’s Jackson. “This wouldn’t be a problem if the tunnels didn’t work so effectively. If they hadn’t done so well at making economic life and social life and human life move across this divide, they would be just fine.”

After about an hour, the lights finally come back on. There isn’t any aha moment. Diligence and methodology finally get the intergenerational hardware and software to communicate. Now that everything’s working, the local news has moved on, the traffic jam has cleared, and skiers and truckers are speeding through the tunnels without really noticing them. They’ve become invisible once again.

This article was originally published in 5280 July 2024.
Nicholas Hunt
Nicholas Hunt
Nicholas writes and edits the Compass, Adventure, and Culture sections of 5280 and writes for