I have taken this advice from a very experienced person.
Try as much as possible not to vomit.coz once u do there r very rare chances of the person surviving a severe accident.
if u r lucky to find urself even a bit conscious then take a moment, relax and come back to the real world. have lil water.
Finally Thank God for making you survive ur crash.
(Say all is well )
"But try to avoid vomitting". It can save ur life