I must say it always struck me as one of the more dangerous forms of racing. It's like the worst of bike-racing and single-seater racing combined, with none of the safest elements of either. One one hand there's nothing protecting you at proper race car speeds, and on the other you can't get off it easily if things go wrong.
I digress, of course they all know the risks far better than I do.
Always a shame when someone dies doing something they love, and as xaotik said, the person that hit him will live with that for the rest of his life, it doesn't matter whether he could have done anything about it or not.