I'm not sure who else here has experience running motorcades in Iraq, but I'll pass on a few points:
1) We NEVER took video of our motorcade operations for the simple reason that videos like this only show a very narrow slice of events, and that slice is never enough to show the totality of circumstances involved in your actions. It can only hurt, never help.
2) There didn't seem to be anything at all random about the shooting in the four strung-together clips I just watched. Individual vehicles were addressed, not whole landscapes or fields of fire. Those vehicles all had something in common: they all approached the motorcade follow car. When I was running motorcade ops and driving the follow car, great pains were taken to ensure that everyone on the road understood that we would not be passed and that a close approach was not allowed. I'm not going to go into methods here, but suffice it to say that everyone driving in our AO knew what three Suburbans in a tight package meant, and knew what the rules of engagement were.
3) In the first segment of the video, notice how the white van is going noticeably faster than the rest of traffic, and is passing everyone else on the road precipitously before being engaged by the follow car gunner. This is what they call "a clue." An Iraqi's vehicle represents a significant percentage of their family's assets and is not hazarded lightly. Also, after a few generations of living in a police state, where state violence is essentially unappealable and random and the upraised nail gets hammered down, people just don't drive that erratically or fast. They tend to stay in their lane and drive with blinders on with their heads down.
The white van also does not start reacting to the incoming fire for about fifteen or eighteen seconds. Another clue. Iraqis are survivors, and can spot a rifle muzzle a long way off when it's trained in their direction. Ignoring incoming full-auto fire is not SOP for Ma and Pa Hadji.
4) In the second segment, with the Mercedes sedan, what appears to be an initial burst of warning fire is again ignored. The second burst is more likely trained into the grille or engine compartment, but the resolution of the video is not good enough to tell. Of course, the most reliable target to stop an oncoming vehicle is the driver's face, but I don't see the windshield coming apart in this clip.
Expensive, late model --reliable-- German sedans were known to be the delivery method of choice for suicide bombers while I was there.
5) In the third segment, notice that a smoke grenade is the first attempt at a warning given. The target vehicle drives straight through the smoke and closes with the follow car when it slows down. At this point a few bursts are fired and the target vehicle swerves to driver's right and stops, at which point the fire ceases.
6) In the final segment, the target vehicle enters the roadway behind the motorcade from an on-ramp --standard practice for suicide bombers and small arms fire ambushes-- and approaches pretty quickly, even though the follow car is stopped. Iraqis generally don't approach stopped traffic at a high rate of speed without ill intent in mind. The initial bursts of fire don't show in the windshield, so they're apparently directed at the engine compartment. As the vehicle fails to react to initial fire, the fire is trained on the windshield. Once the vehicle stops, so does the fire.