A cavalcade of US federal marshals accompanied a truck that reportedly was carrying a nuclear missile. They appeared to be taking all possible safety precautions, including armored vehicles with machine guns on the ground and several helicopters in the air.
(Warning: strong language!)
While the motorcade was passing a driver taking the video, one of the armored vehicles hit the rear end of the truck it was escorting.
The video shows that the feds made the rest of the traffic pull over and clear the way, and also demanded that the person taking the video not film the convoy. He protested.
After the rear-end incident, the convoy continued on as if nothing had happened.