Time will no doubt tell what caused this terrible tragedy but look everyone, don't forget that the people who decide to undertake, tailgate etc. are just better drivers whose 'superior' skills and cars mean they're capable of such manoeuvres without any problems at all. They don't cause accidents and don't need to take account of anyone else on the road, how they wish to drive or indeed the rules.
I had one such 'superior' driver tailgating me very recently. I was doing 30 on a 40 stretch of 'country' road in the heaviest rain I've seen in ages. I'd left plenty of room in front of me and lowered my speed as the heavens opened but was obviously doing something terribly wrong in the eyes of the 'superior' driver behind me...
Another thing I've noticed recently is the habit of some 'superior' drivers who, at traffic lights when there's even a short queue to turn left, will pull into the turn right lane only to accelerate hard and turn left on the red/amber phase. With all these 'superior' drivers around I'm beginning to think I need to take lessons...