Blood alcohol concentration (BAC) is a measurement used to determine whether a person is operating a vehicle over the legal limit, which is.08%. Every drink a person has causes more impairment and brings you closer to the legal limit, at which point you can be charged with a DUI. The Centers for Disease Control and Prevention explains how each drink affects your brain and body.

Three drinks

Three standard drinks result in a BAC of .05%. At this point, people find it hard to follow moving objects with their eyes and will likely experience some loss of coordination. This is often exhibited by problems steering and diminished response to unexpected occurrences on the road, such as a wild animal crossing your path or a stopped vehicle. Judgment will also be impacted, which makes it difficult to operate a vehicle safely.

Four drinks

Just one more drink causes a BAC of .08%, which makes it illegal for a person to be behind the wheel. Impairment becomes more pronounced, with problems with short-term memory, trouble concentrating, and trouble with perception. Muscle coordination also begins to break down after four drinks.

Seven drinks

On drink seven BAC can be as high as .15%. Driving ability is severely limited after seven drinks, and loss of muscle control, inattention to driving, and vomiting are also quite likely to occur. Information processing is also seriously impaired when BAC is this high. Keep in mind that standard drink sizes change depending on the potency of the alcoholic beverage you’re drinking. Also, people with a lower body mass may get drunker more quickly.