The small appears to be blaming the black car but it’s the white car that attempts to overtake the van obviously without looking in the mirrors hitting the black car and causing the crash, whose fault was it?
Mr/Mrs N. ervous gets too close to a slow vehicle in front of them, they keep looking for a decent stretch of clear road so they can overtake (missing about half a dozen opportunities) They get that focussed on waiting for the worlds longest bit of straight road with no oncoming vehicles that they forget to look behind them when making their move and unfortunately on this occasion ... BOOM!
IMO it should depend on the speed involved. If all at driving at normal speed then the white car should have noticed that it wasn't safe to pull out. But if the black car was charging down like a maniac it can be argued that it would have seemed far enough away to not be considered a danger, and that it's excess speed, resulting in it reaching the others, was the cause.
OG, if the black car was travelling at an excessive speed surely the driver of the white car would have noticed how fast he was approaching, if he had use his mirrors.
If you had looked in the mirror, the speed of the black car would be irrelevant ... it was already in the lane it needed to be to overtake, so any sensible/good/alert/half-decent driver would not have pulled out.