The Eisenhower/Johnson Tunnels are a Colorado wonder that most I-70 motorists probably take for granted, but here are five interesting facts you didn't know about the state's longest tunnels.

The Eisenhower Tunnel was originally called the Straight Creek Tunnel, named for the valley where the west portal is located, but was officially named the Eisenhower Memorial Bore before it opened in 1973. The second tunnel opened in 1979. The twin tunnels span 1.6 miles and are the highest vehicle tunnels in the world at 11,155 feet. Now we call them the Eisenhower/Johnson Memorial Tunnels.

HUGE ELECTRIC BILL

If you thought your utility bill was high, this may give you a new perspective. The monthly electric bill for the tunnels is about $70,000. Think about that the next time you are driving through and see all of those lights whizzing by.

IT TAKES A VILLAGE

Have you ever thought about how many people it takes to keep the tunnels operating on a daily basis? A total of 52 full-time employees are responsible for round the clock television surveillance using 38 monitors, emergency response, tunnel washing, ventilation maintenance, sweeping, snow removal, water treatment, and heavy equipment servicing and repair.

1,300 CARS EVERY HOUR

In 2015, the tunnels saw an average of just over 32,000 vehicles pass through each day. The most traveled month was July with nearly 40,000 vehicles per day, while the least traveled month was April with just over 26,0000 vehicles.

FATAL CONSTRUCTION

The first tunnel, named the Eisenhower Memorial Bore, was finished in 1973 and took five years to complete. The second bore was started in 1975 and took four years to complete, named after Edwin C. Johnson, a past governor, and U.S. Senator. During construction of the first tunnel there were three fatalities, and during the second bore construction, a total of four people were killed.

TUNNEL OF STEEL

While one million cubic yards of material was cleared from each bore, 190,000 cubic yards of concrete was used for the lining of each tunnel. The Eisenhower Tunnel itself contains 10,000 tons of reinforcing steel bars, and over 23,000 tons of steel in the tunnel. More than 1000 workers were employed during construction of the first tunnel working various shifts 24 hours a day six days a week.

[CODOT.GOV]