Not all that long ago (okay, about 15 years ago) I was on foot patrol, uniformed, fully visible, police high viz jacket and all that, when I saw a car just like that one start to move off from a parked position, driving towards me. All windows were fully iced up, snow on the screen, just a tiny letterbox attempt had been made to clear a peephole. It was the worst one I'd ever come across, easily.
I stood and made the "palm up" stop signal, but there was no sign of him slowing... I (possibly foolishly) stepped into the road partly and made myself as much in his eyeline as I could, but still he kept going. As he went by, I slapped my hand on the side of the car. He stopped.
Before I could even go into the spiel of "Good morning sir, do you know why I've stopped you" etc, knucklehead gets out and wants to get into a fight wanting to know if it was me that had "slapped his car". Hadn't dawned on him that it was probably quite bad that the first time he'd noticed me was when he'd got out of the car to see what the noise was.
Sadly there's no intelligence / common sense requirement to drive a 2 ton box of kinetic energy and there are some real mouth breathers out there.