The Prosecutor may believe that he/she can prove that you were operating the vehicle within 2 hours of when the officer made the arrest. Obviously, a prosecutor can charge a person with whatever they want. Next they must prove (beyond a reasonable doubt) that you committed the crime.
Driving under the influence.
(1) A person is guilty of driving while under the influence of intoxicating liquor or any drug if the person drives a vehicle within this state:
(a) And the person has, within two hours after driving, an alcohol concentration of 0.08 or higher as shown by analysis of the person's breath or blood made under RCW 46.61.506; or
Different states have different definitions of what constitutes "driving" or being "in actual physical control" of a vehicle. However, it's my experience that there are very few juries who would convict on the fact situation that you have submitted, no matter what the law says.
There is a possibility that you can be charged with being in actual physical control of a motor vehicle while under the influence, which is similar to DUI (carries the same penalties, etc) - or if they believe they can prove you drove a motor vehicle within 2 hours with that BAC level, they can certainly charge it.
Whether they can prove it or not, that's a different question.
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