To me the biggest issue is that there doesn't seem to have been any braking attempt, even at very close distance. Even if it was imperfect or hard to see at a d

To me the biggest issue is that there doesn't seem to have been any braking attempt, even at very close distance. Even if it was imperfect or hard to see at a distance, I would expect to see the 75mph reduced even slightly before impact. Every speed reduction is a statistical increase in surviving a crash.