Should I go to trial if I am being charged for a DUI when my BAC was .05 but the cop thinks I was stoned at the time?

Well either you go to trial or take the deal. It is your call.

In Michigan any amount of an illegal controlled substance and combination of alcohol can lead to a charge of impaired driving or OWI(OUID) Operating under the influence of drugs. This normally requires a forensic blood or urine test to show the presence of drugs. A .05 BAC without more is insufficient to provide OWI (DUI) and even an impaired driving charge.

You should be talking to your attorney about this, since your attorney knows more about your case than anyone on this forum.

I would have to see the police report and the Commonwealth's evidence against you before I would advise whether or not to go to trial. However, a BT of .05% is below the legal limit. You shouldn't even be charged with OUI alcohol with that reading. OUI Drugs are very hard cases to prove on the part of the Commonwealth since there are no standards that show how much marijuana is required to impair your driving. There is no .08% standard like with alcohol to measure you against. I would definitely have a consultation with another attorney. If you can afford private counsel, you should get a copy of your police report and make an appointment with a good OUI lawyer. I don't think I have ever pled an OUI drugs. The cases are just too hard for the DA to prove. All that I say applies only to Massachusetts. If you are from another state, disregard anything said here and consult an attorney in the state where you are charged. In MA, there is barely any difference between the sentence from a plea and a Guilty at trial for an OUI, which further causes me to lean towards trial in cases that are close calls. I am not even sure if your case is a close call. I don't know what type of "expert" your lawyer spoke to but I would want to know their credentials before taking their advice. Until the Commonwealth comes up with standards that show, through scientific analysis, what it takes to "impair" one's ability to drive from smoking pot, I would be inclined to try OUI drug cases. It sounds like they don't know how much you smoked, when you smoked, how strong the marijuana was or your tolerance to marijuana. Without being able to identify all or at least most of those issues, it seems like a lot of reasonable doubt to me.

It depends what kind of deal they are offering. Drug DUIs are very difficult to prove, and a reduction, at a minimum, should be your goal.