The United States has more than 500 tunnels and over 300 of those are on highways. Given the dramatic geographical features of our country, tunnels are essential to mobility.
That freedom to move across the continent would vanish without proper maintenance of tunnels.
California has the most tunnels with 101, and Alaska’s Anton Anderson Memorial Tunnel is the longest in North America at 2.5 miles.
But to appreciate what goes into tunnel maintenance, let’s examine the highest public trafficked tunnel in the country — the Eisenhower-Edwin C. Johnson Memorial tunnel in Colorado.
Located approximately 60 miles west of Denver, the tunnel sits 11,112 feet above sea level and stretches 1.7 miles beneath the continental divide. When it opened in 1979, it was the highest vehicular tunnel in the world.
The Eisenhower tunnel transports westbound travelers, the Johnson tunnel carries the eastbound lanes, and each is sloped with a 1.64% grade.
An average of 35,422 vehicles pass through it each day, and in the five minutes it takes to reach to the other side, most drivers probably don’t consider the large, dedicated team of workers who are responsible for the extensive maintenance of the tunnel.
Michael Martinez, Labor, Trades and Crafts (LTC) Operations Manager Ops 1 of the Colorado Department of Transportation (CDOT), manages a team of 40 employees who oversee the tunnels’ upkeep.
“We all have different jobs at this tunnel,” Martinez said. “Electricians, tunnel mechanics, even a dedicated fire department. And then we have a new headquarters up here for our administrative staff.”
This is a world motorists don’t see. And if Martinez’s team do their job properly, drivers don’t notice much about the parts of the tunnel that are visible. Excavated height for the tunnels is 48 feet with a width of 40 feet. The ducts are located above a suspended ceiling, and drainage is provided below the roadway surface, making it so the driver only sees 16 feet of the roadway to the suspended ceiling.
The upkeep of the tunnel happens on a continual basis, with some tasks needing to be completed every day, some annually, and always with safety for workers and motorists top of mind.
Richard Roybal, Electrical Trades III (ETIII) of CDOT, said the team’s hard work is a labor of love meant to preserve the historic tunnel.
“We know the quality and the effort that it takes to make something work well and we’re trying to cultivate that here,” Roybal said. “Because [the tunnel] is historical, it's something that we're proud of and we want to make it last for a very long time. We're putting our whole hearts into this. Anything we could add, anything that we could do to make it better, we want to do.”
Each day, Roybal manages a group of four people who perform maintenance on “pretty much anything that moves in the tunnel.”
“If it's a door, a fan, a fire alarm system, or changing breakers or anything that breaks overnight we come in ready to fix what we need to,” Roybal said. “Right now, we’re in more of a reactive state. We’re working on a preventative maintenance (PM) program that will have us making sure equipment like the fans and alarm systems are checked every month. We’re trying to be more proactive.”
The proactive approach includes keeping the roads and walls clean and clear of debris. This isn’t done overnight; it’s an extensive process that can take over two weeks.
“Three times a year, we use a tanker with a spray system located at the rear of the tanker that washes the walls and road,” said Martinez. “We first go in with a team of tunnel mechanics and master electricians and change out burnt bulbs and ballasts.”
After that, the tunnel maintenance crew pulls up drain covers of all drains. Another crew operates follows behind them a vac-truck. They clean out clean out the gutters from any road grime or debris that may be built up inside those drains, according to Martinez. Once this is done, the team of sweepers will come through and pick up the debris and dirt in the roadway and gutters.
“The next pass has a detergent we use to help clean the tiles on the wall and give them a sheen,” Martinez said. “The final pass cleans off any remaining grime from the walls, ceiling, and roads.”
The 5,600 lights illuminating the entire length of the tunnel requires consistent attention, as well.
“The main thing that keeps the motorists safe is the lighting in the tunnel,” said Roybal. “We change the bulbs and the guts of the fixtures every year. So, it’s almost every six months that we're in there working on lights.
Roybal said the maintenance team is working on a new lighting project that will help CDOT control the lasts as motorists approach the tunnel. The project should be completed by the end of summer.
Within the next few years, Martinez said all the existing lights will be replaced by modern LED lights, which will result in energy and cost savings.
Technology Drives Maintenance Efficiency
The team has also employed and began planning processes for various technologies to aid them in their maintenance efforts.
Their control room, which houses traffic and tunnel operations, has recently been relocated to a renovated administrative building that will enable real-time, automatic monitoring.
“What we're trying to focus on is redundancy—the backups to the backups,” said Roybal. “With this new building, we have a backup. So, if the control room caught fire, we now have a backup to control these cameras and run the tunnel.”
The maintenance team’s systems also will be backed up with the help of new uninterruptible power supplies. Roybal said the team has pushed hard for technology that gives them more automatic control.
“Our SCADA (Supervisory Control and Data Acquisition) systems are all going automatic so that we have real time data that we're gathering to help us keep on top of repairs that need to be addressed,” Roybal said.
Ongoing plans to upgrade to digital cameras in the coming years also will assist in the monitoring of the tunnel and its traffic, according to Martinez.
“We’re currently running on analog [cameras] that are fuzzy,” he said. “The new digital cameras that we have provide panoramic zoom and give us a clearer picture of what's going on in our control room whether that’s with a fire or a car breaking down.”
The cameras also provide more information like license plates or how many people are in the tunnel at any given time.
A new Advanced Traffic Management System (ATMS) will be installed so the public will be able to view what the maintenance crew sees.
“They won't be able to make any changes to our operations, but they'll be able to see what's going on and where the money's being spent,” Roybal said. “On our side, CDOT workers will also be able to see things like the fan control room in real-time to know what’s happening in the tunnel.”
Connecting Communities
The engineers who designed the Eisenhower-Johnson tunnels identified the need to connect the divided Clear Creek and Summit counties.
The continental divide, a line of granite that snakes north to south through Colorado, physically and economically separated the Western Slope from the Eastern Plains. Although travel over the state's mountain passes was possible, it was often difficult and dangerous.
The need for a tunnel under the Continental Divide dates to 1867, when W.A. Loveland wanted to build a railroad tunnel. However, the project was too extensive for early engineers, so Loveland opted to build over the divider.
The idea of tunneling under the Divide was resurrected in the early 1940's, but it was not until the 1960's that adequate technology and funding existed to make the construction of a tunnel a reality. In 1964, a pilot bore was started where the Johnson tunnel (south bore) is now; it was holed through on Dec. 3, 1964.
Construction on the Eisenhower tunnel started March 15, 1968. At the height of construction, as many as 1,140 people were employed in three shifts, 24 hours a day, six days a week. It opened on March 8, 1973, with a cost of $116.9 million, and 2.2 million vehicles went through that year.
Construction on the Edwin C. Johnson tunnel started in 1975. Serving eastbound traffic, it opened on Dec. 23, 1979, with a cost of $144.9 million.
From March 8, 1973, through Feb. 27, 2023, more than 434,000,000 vehicles have traveled through the tunnels.
There “has never been a traffic fatality within the tunnels,” Martinez said. “We’ve had fires, but never a fatality.” RB
