You didn’t want to put anyone in danger. You didn’t want to get a DUI. After you went out with friends, you decided not to drive. You stayed the night at a friend’s house, woke up on the couch and only then got in your car. You had to go to work, after all.

You may feel like you did everything right, and you certainly had the best of intentions, but you do need to know that your blood alcohol concentration (BAC) could still be over the legal limit. If it is, you could get a DUI the day after drinking. Just because you went to sleep on that couch for a little while does not mean you’re in the clear.

What you need to remember is that your BAC needs time to fall from wherever it was last night. Time is the only thing that makes it drop. The fall is slow: about .02% per hour.

Nothing changes that decline after the fact. Go ahead and drink coffee or take a shower. These are common ways people think that they can sober up. They don’t work. They may help you feel awake and alert, and you may think you’re getting sober. From a scientific perspective, though, you’re not.

That’s not to say that nothing impacts BAC. Things like height, weight, gender, eating habits and much more can determine how long it takes you to get drunk or how high your BAC climbs per drink. Everyone is unique. But nothing changes how fast it falls after the fact.

Did you get arrested on DUI charges? You need to know what legal options you have moving forward.