Wow. That sounds crazy and is pretty much my worse cycling fear (e.g. waking up in a hospital from an accident).
After getting the bike from the police a week later, it turns out the crash was caused when the left blade of front fork of my 2003 Trek suddenly snapped in two.
I've heard of carbon forks failing, but never without some kind of impact.
Have you gone back to the place of the accident and see if there were any road imperfections or potholes you could have hit?