You are looking at the map of the routes followed by the nuclear trucks—plain-looking, high-tech trailers that travel America's busiest highways carrying nuclear bombs, material for atomic weapons, radioactive metals and nuclear fuel for the US Navy.
All this nuclear material is transported "from a variety of labs, reactors and military bases, to the nation's Pantex bomb-assembly plant in Amarillo, Texas, to the Savannah River facility" by trucks that look like any other from the outside.
Called Armored Tractors (ATs), these 18-wheelers are heavily shielded, continuously tracked, and loaded with security measures. Nothing differentiates them from other commercial trucks save for a few antennas and their special architecture. That and a "US GOVERNMENT" license plate. And the fact that they're loaded with stuff capable of destroying a few cities, for course.
But don't worry. The DoE's Office of Secure Transportation is taking good care that nothing happens to all these nuclear trucks constantly on the move. The fleet is operated by 600 special agents from the Department of Energy with a $250 million a year budget.
Check out the original article at Mother Jones. It's fascinating—and somehow terrifying—that this happens every single day without anybody noticing. [Mother Jones and Sandia National Labs via Public Intelligence]