The car that hit the truck actually bumped it first, and then it looks like the driver panicked, or something broke, and the car turned right into the truck's front wheel. It may have been a tire blowout that sent the car out of control to begin with. It's hard to tell. But look at the very beginning of the accident, and you will see the car just graze the truck near the trucks back wheels, before swerving to the right, and then back into the truck.
My best guess is that the car had a blowout, swerved into the truck, the car driver slammed on his brakes, and physics took over. NEVER slam on the brakes with a blowout. Your car will do just what that car did.
There is a small silver-looking SUV that basically goes right under the airborne truck just after it goes over the wall. THAT driver was quite possibly the luckiest person on the planet that day.
CD