That video really makes me miss driving on the autobahn.
If you see a white cloud of smoke shoot straight up, hundreds of feet into to the air in an instant, you know someone up ahead just put on their brakes hard and it's time to slow down. It was usually caused by eastern european truck drivers that would get into the left lane to pass even slower trucks on tiny little hills.
It looked like that guy waited too long to brake when the left lane became clogged and that he was going to crash into them, but the video cuts out and starts again later. He probably braked so hard the cameraman accidentally clicked the off switch. I'd pull over and clean the windshield long before letting it get as dirty as he did. You need an extra clear view of the road at those speeds.