Specifically, state troopers are supposed to be ensuring that no one obstructs traffic on Redwood Road, said the superintendent of the Utah Highway Patrol, Col. Daniel Fuhr.
"It's not security on the interior of the property," Fuhr said.
The NSA issued a statement Wednesday saying no one incident precipitated the contract with the UHP.
"The National Security Agency takes responsible measures to ensure the security of our workforce," the statement said. "Operating cooperatively with local law enforcement where our facilities are located is an absolute priority to ensure safety for the community as well.
"NSA routinely partners with federal, state and local emergency responders at domestic locations," the statement added. "For a variety of operational security reasons, NSA does not disclose the full range of these relationships."
Fuhr said a trooper is stationed at the Utah Data Center at all times.
The NSA is paying overtime rates — about $50 an hour — to UHP and troopers who are otherwise off-duty from their state jobs.
Most of that money goes to the trooper, but UHP keeps some to cover administrative costs, Fuhr said. The NSA also is paying mileage on the UHP vehicles.
The Utah Data Center is a massive storage facility for digital information collected by the NSA. The agency had said it would be operational in fall 2013, but has refused to provide any updates on its status.
As have all NSA facilities and programs, the Utah Data Center has come under scrutiny since spring 2013 when then-government contractor Edward Snowden provided journalists with files detailing NSA workings. The files disclosed the mass gathering of America phone and Internet records as well as foreign spy programs.
In Utah, an organization called Restore the Fourth has led protests against the NSA and the Utah Data Center. Redwood Road is also State Road 92, and Restore the Fourth adopted the stretch of road outside the data center. The group has picked up litter while carrying protest signs.
Lorina Potter, a representative of Restore the Fourth, said she has never noticed any state troopers at the data center. Restore the Fourth — whose name is a reference to the Constitution's Fourth Amendment, which bars unreasonable searches — picked up trash on Redwood Road on Independence Day and did not encounter any troopers.
Potter questioned why the NSA needs to spend the money on the troopers.
"I guess it's a preventive measure for something that there's never even been a hint of need for," Potter said. "It's like over-preparation."