Your Blood Alcohol Concentration may play a very big role in a DUI arrest. If you're over the legal limit of 0.08% BAC, the law assumes that the alcohol impaired your ability to drive.
However, drinking does not impact everyone in the same way. You have to take all sorts of factors into account, such as how much food you ate or how often you drink. You could have the same amount of drinks as a friend and your BAC could exceed the limit, even when theirs does not. Don't ever assume it's identical.
Time and weight
Two of the biggest factors to consider are the amount of time after a drink and your body weight as you drink. The more you weigh, the less one drink is going to raise your BAC.
For instance, after one hour of drinking, a 100-pound person who had just one drink would have a BAC of 0.021. A 200-pound person, on the other hand, would have a BAC of just 0.002. Neither person breaks the legal limit, but the smaller person is about a quarter of the way there, while the heavier person barely moves the needle.
Let's compare the two if they each had three drinks in that hour, rather than one. This is when you start getting into potential legal trouble -- though you can get a DUI even under the legal limit.
The 100-pound person, with three drinks, would have a BAC of 0.095. They are now just over the legal limit. If they get pulled over and take a breath test, that's enough evidence for an arrest on the spot.
The 200-pound person, though, who also had three drinks over an hour, would have a BAC of 0.038. They are about halfway to the legal limit. They could still get a DUI if the police can show that the alcohol impaired their driving, but they will not get it just because of breaking the limit on a breath test.
This is why you can never assume that the alcohol is the same for you as it is for anyone else. Peer pressure sometimes plays a role. Say you go out with friends who are all larger than you. They may pressure you into having an extra drink, wrongly assuming that it won't be a problem because the alcohol isn't hitting them too hard, when you actually feel far more drunk -- even after fewer drinks.
After an arrest
In any case, if you get arrested on DUI charges, it is important to start thinking about your legal defense options. Remember that these charges can have a drastic impact on your future and you need to know what steps to take.