If the police were not involved, the likelihood of you being charged with a DUI is minimal. The prosecution would need to have proof beyond a reasonable doubt that you were under the influence at the time of the collision. Without a chemical test, they can't establish that you were under the influence. Well... I suppose they could try if they wanted to call as witnesses people who saw you drinking, establish how much you were drinking over what period of time, then try to get a criminalist to testify what blood alcohol level they would expect you to be based on how much the witnesses saw you drinking and your body weight...

It's theoretically possible, but unlikely.

I agree with Mr. Dane that it's unlikely, but you should still be very careful about what you do from here on out.

DUI with injury under Vehicle Code 23153(a) is a felony. The prosecution wouldn't have to prove that you had a certain blood alcohol level, only that you had consumed alcohol to such a degree that you were incapable of driving a car safely.

If witnesses said you smelled of booze, and were slurring your words and stumbling all over the place, that would be enough to charge you with felony DUI, although a jury might not convict you.

If contacted by the police, you should tell them you will not talk to them without an attorney... then stick to it, whatever they say. In addition, don't talk to anyone else but a lawyer about what happened, because your statements to others could also be used against you.

Can you? Of course; the 'can' do anything. Could you be convicted on that evidence is the question for the DA to assess. If you are charged, feel free to contact me if serious about fighting it.