Re: How do go from 120 on the freeway, spin a couple of times and then stop!
what tyre pressures were you running and how often did you check them?
most sudden tyre failures like the one you describe are caused by internal heat build up.
if it's been pierced by something, you'll normally have a fairly controlled deflation.
blowouts usually come from the heat caused by steel belts rubbing together, due to underinflation. it could even be that a slow leak has inadvertently left you with less pressure than you thought.
when the pressure goes down, the heat goes up, then bang.