National Nuclear Security Administration Office of Secure Transportation

The https://en.wikipedia.org/wiki/U.S._Department_of_Energy/http's Office of Secure Transportation (OST) provides safe and secure transportation of nuclear weapons and components and special nuclear materials, and conducts other missions supporting the national security of the https://en.wikipedia.org/wiki/United_States_of_America.
https://en.wikipedia.org/wiki/Office_of_Secure_Transportatio

OST-https://en.wikipedia.org/wiki/Classified_information shipments are now conducted in a low profile (no uniforms are worn by agents or signage posted on vehicles), no-notice manner to ensure the security and safety of the cargo. The personnel who operate the transportation vehicles and the escort vehicles are federal agents. The OST annual budget is about $250 million.

The OST is in charge of the nation's nuclear shipments including nuclear weapons maintenance transportation to and from DOE facilities, fissile material transport, nuclear reactor fuel shipments, and other classified shipments.

OST crews are federal agents with advanced defense weapons and communications systems.
As of 2012, OST employed about 350 couriers. It seeks to hire military veterans, particularly ex-special-operations forces. Besides dealing with "irregular hours, personal risks, and exposure to inclement weather," agents "may be called upon to use deadly force if necessary to prevent the theft, sabotage or takeover of protected materials by unauthorized persons."



The Safe Secure Trailer (SST) and Safegaurds Transporter (SGT)
The most advanced and secure transportation semi truck on the road today. SSTs, SGTs and escort vehicles are heavily armored with advanced classified defensive weapons and communications systems.




George Knapp (Yes, the reporter from Nevada who chases UFOs and aliens at Area 51 and broke the Bob Lazar story) thought these guys were M.I.B.s (Yup, Men in Black)