The 2008 movie “City of Ember” is about an underground city that flourished for years until its electric generator began to fail. On the U.S. interstate system there is what amounts to a self-sufficient underground city that continues to flourish and has ample generator and backup generation capacity to continue for years to come. An impressive engineering feat, the Eisenhower Memorial Tunnel on Interstate 70 is fully equipped to do just about anything you can imagine, including allowing for an easy flow of traffic through the Rocky Mountains. It is essentially an underground city itself.

Located approximately 60 miles west of Denver, the Eisenhower Memorial Tunnel is the highest vehicular tunnel in the world. According to the Colorado Department of Transportation (CDOT) Web site, the tunnel reaches an elevation of 11,013 feet at the east portal and 11,158 at the west portal. The tunnel has an average elevation of 11,112 feet and traverses through the Continental Divide (which separates two watersheds), has entrances in two counties and is entirely within the Arapaho National Forest.

Mike Salamon, CDOT tunnel superintendent, suggests the benefits of the tunnel to the trucking industry are immense, not only in time saved, but in safety and miles too. “From a trucker’s perspective, the access to the Eisenhower Memorial Tunnel cuts off about 30 to 45 minutes of drive time over Loveland Pass,” says Salamon. Loveland Pass is the “old route” a driver would take if he or she wanted to cross the Rocky Mountains from Denver heading west. “Loveland Pass is a difficult drive with hair-pin turns and you have to climb an extra thousand feet in elevation,” explains Salamon. Of course, with a 1,000-foot climb there is also an extra 1,000-foot descent. “The tunnel is simply a friendlier drive,” says Salamon.

The CDOT Web site offers many specifics about how this is so. For example, “the average grade of both tunnels is 1.64 percent rising toward the west. The westbound tunnel curves slightly to the left about midway into the mountain.” There are steep approach grades, however, with grades of seven percent on the west approach and six percent on the east approach (A grade is measured according to the number of feet one ascends or descends per 100 feet traveled).

In addition, these tunnels of 1.693 and 1.697 miles are very well lit, adding to the safety of the system. “The tunnels are lit with new fluorescent lighting, so there are no issues with lack of light,” says Salamon. In fact, the lighting in the tunnels rarely is consistent. “Light levels are automatically controlled and adjust to the temperature and outside light levels. This just adds an additional element of safety by not having the driver’s eyes have to adjust too much,” says Salamon.

In addition, the width in both bores provides two traffic lanes of 13 feet each, providing a total travel width of 26 feet. “Safety is the priority in the tunnels, and these are well designed to provide just that,” says Salamon.

The tunnels are so well equipped for safety that one might think that they could be a self-sufficient city – and they probably could. With 52 full-time employees, the tunnels are staffed 24 hours per day, 365 days per year. “It is all in the interest of safety and security. We have surveillance video monitors every 800 feet, with a total of 150 surveillance video cameras around the approaches and the structure itself,” says Salamon.

The safety record of the tunnels speaks for itself. In 35 years, 265 million vehicles have traveled through the tunnels. “We have never experienced a fatality inside the tunnels,” Salamon states proudly. “It’s really not luck … it’s the result of our commitment to safety. With intense surveillance and staffing we are able to respond to any situation immediately, lessening the chances of fatalities or other serious issues.”

An example of how CDOT can respond to issues in the tunnels is their use of wreckers. The tunnels have two wreckers on the facility at all times and are immediately available when something occurs. “Any time a vehicle stalls or experiences difficulties we respond immediately and remove it instantly,” says Salamon. The tunnels see 400-500 emergency wrecker runs per year, so these wreckers do remain busy. “If you think about it, that is potentially 400-500 accidents that could occur if we did not staff the facility and have the wreckers on site,” explains Salamon.

Most of the wrecker runs come on hot days. “It is hard on vehicles to climb the 7 percent grade and reach 11,000 feet. We see a lot of vapor locks and catalytic converter issues,” says Salamon. On the warm days, Salamon says that they might see as many as 13 vehicles shut down in an hour. “It becomes very busy,” says Salamon.

With the tunnels being so integral to the trucking industry it is also important to understand that any tunnel has a natural height restriction and these tunnels are no different. The vertical clearance in the tunnels, as of 2008, is 13 feet 11 inches. It was 13 feet 6 inches before that, but they have installed new, smaller message boards allowing for more clearance. The tunnels monitor the height requirements with sensors. “There is always someone staffing the portals and monitoring the sensors. If an over-height vehicles tries to enter the tunnel, traffic lights signal, alarms go off and sensors go off. The staff will then go to the vehicle and physically measure the truck to determine if they can have access,” explains Salamon.

Another safety aspect of the tunnels is that they basically have their own fire department on location. The tunnels are quite a distance from any town, so response times would be slow if there were a need for a fire truck. “We have our own fire truck on site that has a water cannon and foam capabilities,” says Salamon. The tunnels also have fire hydrants every 250 feet through the tunnels and they have their own 120,000-gallon underground reservoir.

As it turns out, the fire truck has come in handy on more than one occasion. “Vehicles do catch on fire, and they are just as likely to catch fire in the tunnels as they are elsewhere, so we need to be prepared,” says Salamon. He says more than one motor home has gone up in flames, largely due to the propane tanks. “In fact, the longest closure we have had in the tunnels was due to one of the motor home fires, and that closure lasted eight hours,” says Salamon.

The tunnels have also seen fires as the result of ski bus fires, but perhaps the scariest instance was when a vehicle loaded with guns caught fire. “We had a vehicle catch fire in the tunnels once, and the trunk was filled with ammunition and guns. The ammunition was going off when the guys were in there putting out the fire. This is certainly something we want to avoid in the future if we can,” says Salamon.

From a trucking industry perspective, hazardous material loads are generally not allowed in the tunnels. “We restrict hazmat loads from accessing the tunnels, unless the alternate route is closed,” explains Salamon. If the alternate route is closed, the tunnel operators will allow hazmat loads through the tunnels once per hour, at the top of the hour. “It’s all in the name of safety,” says Salamon.

Other safety measures in and around the tunnel are also readily apparent to the traveler. Message boards are located every 800 feet to advise motorists of weather conditions outside the tunnel, upcoming accidents or delays or any other item that needs to be communicated. Also, during the winter, vehicles are required to have chains and there are specified areas along the corridor (but not in the tunnels) where drivers can chain up.

It should not be surprising that in addition to these incredible safety measures, with the steep grades, there is a concern of runaway trucks. As a result, there are two runaway truck ramps on the westbound side.

In addition to safety measures, there are other impressive aspects of the tunnels. Like the city of Ember, the tunnels have their own electric generation facility. The tunnels require 24,000 volts of electricity to be powered. “We have two feeders, one on each side of the Continental Divide, so should always have electricity,” says Salamon. If one feeder line goes down, the other will power the facility. The tunnel’s electric grid requires the employment of electrical engineers and linemen too.

As previously alluded to, the tunnels are self-sufficient in their water supply. This, however, requires that the tunnels have a water treatment plant in addition to the reservoir itself. “The water needs to be treated due to creek drainage and the requirements of the Environmental Protection Agency,” explains Salamon.

The self-sufficient nature of the tunnels is impressive, but a facility of this size requires substantial maintenance as well. There are, of course, the necessary repairs to the roads and structure itself, but one bit of maintenance that many might not be aware of is the cleaning of the tunnels. “We wash the tunnels, including the walls, twice per year,” says Salamon. The cleaning generally takes place around Memorial Day and Labor Day. They wash the tunnels with 180-degree water, biodegradable soap and an impressive brush system that cleans the walls.

The tunnels, newly cleaned or not, also serve as a mountain traffic operation center. “From the operations facility we are able to dispatch to surrounding areas, including police, snow plows and other necessary or emergency equipment,” explains Salamon.

The tunnels also serve as a traffic control point for the I-70 corridor. “Any time an accident occurs along this corridor we are instrumental in traffic maintenance. If we need to, we can shut down traffic either way for safety or other reasons,” says Salamon. The tunnels have the capability as well to run as a two-lane road on one side. This basically allows for an extra lane of traffic going in one direction.

“We have only done that once in recent times, and that was due to high traffic volumes,” says Salamon. In the 1990s CDOT did this on a regular basis during ski season. “Basically we would have three lanes open in the heavy direction, and then they would reverse that when the heavy direction changed back. But traffic has increased so much that it has become too busy, both ways, for us to do this,” says Salamon.

The tunnels are an engineering feat that is largely underappreciated by those who travel through them today. Occasionally the tunnels have seen dogs run through them and deer get in them, and birds are always in there. “Really, the tunnels are self-sufficient facilities that experience the same things most highways do, but they are a far more complex system than most people realize,” suggests Salamon.

“The tunnels are more than just a hole through the mountain you have to go through, they are truly something to be enjoyed,” says Salamon. “As you travel through, be careful, enjoy, and be cognizant of the downhill grades after the tunnel.” Be mindful of the elements, too. “It might be sunny on one side and a blizzard on the other,” jokes Salamon.

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July 1st, 2009 | Category: Featured
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