As a responsible adult, you likely choose one friend or family member as a designated driver when your group goes out. With this safety precaution taken, everyone (with the exception of the designated driver) can enjoy a beer or glass of wine without having to worry about how they will get home. Or do they?

According to a recent article in The New York Times, many designated drivers do not refrain from drinking.

The article cites a study done by University of Florida researchers. These researchers interviewed and did breath tests on more than 1,000 people after they left bars in a Florida city. Of the 1,000 interviewed, 165 identified themselves as the person chosen as the “designated driver,” or the person designated to refrain from drinking in order to safely drive the group home later that night. These tests were done six times over three months.

The results of the survey were rather surprising, as one would expect the BAC of designated drivers to be zero. Though 65 percent of the designated drivers showed no blood alcohol content, 17 percent had a BAC of 0.02 to 0.049, and 18 percent had a BAC of 0.5 or higher.

The study did show that the majority of designated drivers did not consume any alcohol, which is heartening. However, the study’s lead author opined, “The most practical recommendation is that if you drive, you shouldn’t drink at all.”

It’s important to note that the study did not take a representative sample of the U.S. population (those surveyed were around age 28 and of similar ethnicity), so the results can’t be generalized.

Nonetheless, there is an important takeaway from this study: if you plan to drink, choose a designated driver. And if you are a designated driver, make sure that you do not drink at all. Your safety and the safety of your passengers depend on your sobriety.