If a police officer asks a driver "Have you been drinking?", then the driver should either plead the fifth (and not answer the question), or answer the question truthfully. Let's assume the driver only answers yes or no for the moment, without divulging further details. Is there a legal definition or understanding which determines whether the driver answered truthfully? Is the question essentially equivalent to "Do you think you currently have any measurable blood alcohol level?"
Words and sentences have their ordinary meaning, unless a special meaning has been assigned by the legislature or (sort of) by the courts. The legislature may therefore specifically define "deadly weapon" to not include a knife with a 2 inch blade; or it might so define a short blade knife as a "deadly weapon". This expression has no special meaning, therefore it literally means what you think it means. It is used to get detainees to contribute to probable cause, at least in the case of traffic stops. Similarly, the statement "it would help me a lot if I could look in your trunk" is simply a statement of personal opinion and does not require any response by you, nevertheless the expression is used to get people to voluntarily expose the illegal goods in their trunk.
The question is, grammatically speaking, quite vague, so if for some reason you say "no" and they still arrest you (beer breath? whatever their reason), the question is whether you willfully uttered an untruth. It would be incumbent on you (via your lawyer) to present the meaning that you had assumed at the time. If you assumed that the question was, literally, "have you consumed any amount of alcohol in the last 2 hours?" and you had a half glass of wine two hours ago, you lied. If you assumed that the question was "have you consumed enough alcohol that you are now over the legal limit", then you didn't lie.
The interpretation "any measurable blood alcohol level" is highly implausible, since one might measure .001% blood alcohol – it's not a crime to have measurable blood alcohol. The officer's intention is to get probably cause, and the detainee's interpretive strategy should be related to the legitimate interests of police officers in detaining drivers – about levels of alcohol consumption that constitute legally-impaired driving.
Have you been drinking means have you consumed any alcohol when you take it in a literal sense. Now to be a bit pedantic, you will have to excuse me because of the nature of the question.. they should ask "Have you been drinking any alcohol in the last 24 hours" if being literal, but that is not critical as it can be assumed the driver understands it is regarding alcohol, but this is not as literal as it seems. This is because:
The officer will run tests to see if the driver is above or below the limit regardless of the response. If the driver says yes, but less than the legal limit then the officer still has to check the level of alcohol so it is actually just a yes or no question that has the same outcome. They would have seen something to want to pull over the driver to begin with.
I don't recall a case where saying yes has reduced a penalty for a drunk driver, this is because when the officer says "Have you been drinking", it is as good as saying "I suspect you have been drinking and we are going to have to run some tests". most of the time.
To summarise : Have you been drinking? and Have you been drinking any alcohol in the last 24 hours? are almost interchangeable in these scenarios even though they have different literal meanings, but logically they mean the same thing and the officer might as well open with "I suspect you have been drinking and we are going to have to run some tests".
I think this is more a question about English than Law though. There is no special meaning legally that is any different from laymen's terms.
Typically, the cop pulling you over is detaining you, which means they have a reasonable suspicion that a crime has been committed and is investigating. While you cannot leave the scene until the investigation is resolved, you do not have to answer any questions posed to you (save for providing identification) though statements against your interests, if made, can be used against you in the court of law (Cop: Sir, have you been drinking? Driver: Which one of you wants to know hic? are not in your interests).
It can be debatable if they can even use the statements against you in court because of Miranda rules, but there's probably a legal excuse to get them admitted. Really, the purpose of asking is many people (especially drunks. As Ron White recalled from a time he got drunk and police became involved "I had the right to remain silent, but I did not have the ability") would rather verbally defend themselves against the accusation and volunteer information. It could be "I had a glass of wine with dinner before going to see a 2 hour 45 minute (with previews) film and then drove home after we had ice cream and discussed the terrible film for another 45 minutes" or "I'm not as think as you drunk I am." In the later case, it might explain a BAC higher than 0 but less than the legal limit... as an adult would have probably metabolized the alcohol to a safe to drive BAC by that time. In the former, you'll surely be asked to step out of the car, sir.
As Admiral Ackbar so famously said. It is a trap. You have the right to remain silent. If you use this right when dealing with police your chance at a better outcome improves drastically.
Dont speak to them. They are not your friends. You are not obligated to tell them anything. In fact you have the right not to say anything.
Nothing good can come from talking with them and no inference of your guilt can be made from you exercise your right to keep you trap shut.
What the miranda rights conveniently omits is that what you say can be used against you but nothing you say in an interrogation can be used in your defense.
There is literarly no way in which speaking to police in any way further than providing them with an alibi is in your own personal best interest.