>>Who drives into a concrete barrier or the middle of a tractor trailer truck?

I have seen a drunk driver do exactly that.

Someone who falls asleep might also do that.

[edit] Come to think of it, I have almost caused an accident a decade ago. I was momentarily distracted as I turned to talk to my passenger. I was able to brake in time, as a car in front of me had suddenly stopped. Nevertheless, it was only a matter of maybe one second to avoid running into the other car. Me-a-decade ago might been in a similar accident.