A very interesting post Eric, something I'd been wondering about, especially as Marco points out, this is the worst ever year for fatalities. If you consider that most of the riders who died this year were older, more experienced guys, that it was predominantly not towards the end of races, age and tiredness is unlikely to be a factor. While we rarely hear all the circumstances it seems to me the events this year were for largely random reasons, making it hard to suggest any realistic way to prevent the crashes. However I do believe increased use of air fencing could have at least mitigated the effects in most of them.