Exactly. Which is why if this goes to trial, any testimony by this officer about the plaintiff's state of intoxication will likely be inadmissable. I know I'd move to have it excluded if I were the prosecutor.
Not true. Testimony would be admissible. If there was no blood test on the woman, the failure to conduct one must be construed in favor of any player who might be indicted.
The officer could still give a description of what he saw -- e.g., how she moved, glassy eyes, slurred speech, odor of alcohol, etc. -- without testifying to the conclusion of intoxication.