If the police charge you with drunk driving, they will probably base the charge on the findings of a Breathalyzer test. If they can show you tested over the limit, it is much more likely that a court will uphold the charge than if it is merely based on the officer’s observations about how you were driving.
You might think that once you know what the legal limit is, you can work backward and calculate how much you can safely drink. Many people have ended up with DWI charges because they tried to do this but got it wrong, so it’s risky to even attempt it.
That said, sometimes you have a drink before realizing you need to drive later. Here are two things that could help you try and gauge whether you can or not.
What you drank
Some drinks are stronger than others. Some glasses hold more than others. Even drinks in the same category can vary wildly in their alcohol content.
How long ago you drank
There is a big difference between drinking three beers in the hour before you get into the car and having drunk them several hours before. Your body can get reduce your blood alcohol content (BAC) by about 0.015 per hour. That’s based on an average man, and all sorts of things could reduce it for you, so do not rely on it.
Breathalyzer readings are sometimes mistaken. So just because the machine says you are over the limit does not mean you should accept you are. There is always a chance to contest DWI charges.