I know the goal is to be less drunk - not more. However, most people end up hurting themselves when they think they are helping. Let's face it - it's human nature to try to put yourself in the best possible light. That's especially true when you've been stopped by police; no one says I know I was going really fast - I was just hoping I wouldn't get caught. Instead you say I didn't notice, or I didn't see the sign.
There are two questions the police always asked when they suspect you have been driving while intoxicated. The first is how much you've had to drink. Having looked at hundreds - if not thousands of offense reports I can tell you that everyone who goes out has 2 drinks - its amazing that bars can actually make a profit. No one ever says one - I guess it just doesn't sound believable (especially if you've had 10).
The second question is what gets you in trouble. The officer asks you when you had your last drink. Again, the most common answer you get is a couple of hours ago; which can come back to bite you in the you know where.
This all is premised on taking a blood or breath test and getting a result. Let's say you take the breath test, and it comes back as .12 - over the legal limit of .08. If you go to trial, the State's expert will perform what is called a "retrograde extrapolation". That means they take your test result, and extrapolate back to the time you were driving.
Retrograde extrapolation is based on the general assumptions about how your body processes alcohol. The general rule is that you process the equvalent of one drink every hour. So theoretically, if you only have one drink an hour, you're blood level will stay near .00. Once you stop drinking your body continues processing alcohol. If you are still in the absorption phase - which means your body is still absorbing alcohol - your blood alcohol level is increase. That means that if you are pulled over coming out of a bar where you just finished drinking, your blood alcohol result is probably going to be higher than it was when you were pulled over - because you are still absorbing all the alcohol you consumed at the bar.
The flip side of that is that if you are what is called the elimination phase, your blood alcohol level is declining. This is where the time hurts you - and this one time where the police will take what you say as the gospel truth. If your last drink was two hours ago, your blood alcohol level is steadily declining. That means that if you are tested an hour after you are stopped, it will be lower than when you were driving. So even though your test result is .12 they may say you you were higher at the time of driving - maybe .15 or .16 - which makes you more drunk.
The end result is that instead of making yourself look better you make yourself look worse. The best course of action is to keep your mouth shut. They aren't going to believe you anyway - except of course when it comes to extrapolating your test results.