Interesting story. I may be wrong about this, but at some point last year I read that Earnhardt's fatal accident was the last time a NASCAR driver was even taken away from a Nextel Cup race in an ambulance.
In a race yes, but there have been at least three times during practices that I know of. Andy Petty (died), Steve Park, and the name escapes me, the guy who drove the Army car before Nemecheck, also another head injury.