What is the difference between a accident and semi accident?

Other answer:

arezoye:
Never heard of a semi-accident (unless you run into a semi truck). Either it is an accident or a near miss.
STEPHEN:
There's no such thing as a "semi accident". There's either an accident or there isn't.
Obi Wan Knievel:
The only possible difference would be when an 18 wheeler is involved. Semi is another term for the tractor-trailer configuration.
Dan:
You wouldn't ask that if you've ever been in an accident with a semi.
Entidtil:
There is no such thing as a "semi accident" unless you mean an accident with a "semi-truck"?
Timbo is here:
One involve a semi and the other one might or might not involve a semi
Percyqted:
That's like being a little bit pregnant.
hello:
One go boom and one go squish