There are plenty of crashes in road races too. It's not the course, its just racing. A bunch of strong, aggressive guys trying to win a race. Sometimes it results in crashes.
Our most dangerous race around here (in my opinion, of course) is actually on the Portland International Raceway circuit. Wide open, car race (read: gentle) corners, glassy smooth pavement, 2 mile circuit... you wouldn't think that it'd be dangerous at all. But the open course promotes risk taking, and there have been some pretty horrific crashes out there.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --
the tiniest sprinter