A variety of factors can influence a person’s blood alcohol content level (BAC), including gender, weight, body fat percentage, number of drinks and duration of drinking. However, most scientific blood alcohol calculators indicate that a normal adult, consuming a single drink, will not yield a BAC of .08 or higher. As an example, a 95-pound supermodel, who throws back a shot of whisky, then immediately hops in her convertible, would likely have a BAC of only around .05.

In other words, mystery solved; a person cannot drive drunk if he or she consumed only one drink, right? Not so fast. The .08 BAC standard only applies for regular drivers age 21 or older. For commercial (truck) drivers, the number is .04. For drivers age 20 and younger, the legal BAC limit shrinks to only .02. Even if you weigh 180 pounds, a single drink is likely enough to push your BAC above .02.

What’s more, a person’s BAC is not a hard-and-fast number based solely on gender, weight and number of drinks consumed. Other factors can raise your BAC above the normal levels. These factors may include consuming medications, or not having eaten for several hours.

A driver’s BAC is not, however, the sole determining factor with regard to DUI. Florida, like many states, has a two-pronged drunk driving statute. Florida Statutes, Section 316.193 (a) says that a person is guilty of DUI if he or she is “under the influence” of alcohol or drugs, and is “affected to the extent that the person’s normal faculties are impaired.” Put another way, if you have consumed any alcohol at all, and if the state can prove that the alcohol has influenced you to the point that it diminished your normal driving faculties, then you can be convicted of DUI.

Instead of simply establishing what your BAC was at the time the officer stopped you, Subsection (a) focuses more on how you were driving when the officer observed you. At trial, a prosecutor would not focus on evidence relating to BAC but rather on evidence relating to the driver’s behavior at the time. This evidence would include proof of alcohol consumption and evidence relating to the driver’s erratic or unsafe driving at the time of arrest. The arresting officer would likely testify regarding the specific aspects of the accused’s driving that led him or her to stop the driver. Additional evidence might relate to the driver’s performance on field sobriety tests, such as the “walk and turn” or “one leg stand” tests.

In that situation, if the jury concludes that the state has proven that the driver consumed alcohol (of any volume) and drove in an impaired fashion, then the driver may technically be convicted of DUI, even if the driver consumed only one drink.

In sum, the only truly “safe” number of drinks one may consumer before driving, in order to avoid risking a DUI, is zero. However, it is important to protect your rights if you are arrested for drunk driving, no matter what your BAC. Authorities sometimes get it wrong, and the consequences of a DUI conviction are far too high not to ensure your legal rights are not protected every step of the way.