When a person is pulled over for drunk driving, they’ll be given a breathalyzer. These devices measure a person’s blood alcohol content (BAC), which must be under the legal limit of .08% when driving. The more drinks you have, the higher your BAC will be and it takes surprisingly few drinks before you start to feel the effects, according to the Centers for Disease Control and Prevention.
To understand how alcohol increases your BAC, you must first know the standard drink sizes. Different types of alcoholic beverages are more or less potent when compared to others. For example, most beer has alcohol content of about 5%, which means that 12-ounces is normally considered a standard drink. Conversely, wine usually has 12% alcohol content, so a standard drink size would be a much smaller 5-ounces. BAC can also be affected by a person’s weight. That means a person who is heavier will take longer to get drunk than a person who weighs less when they’re drinking the same type of alcohol and the same amount.
Three standard drinks will cause BAC of .05% and already physical effects are felt. At this point, you may have difficulty steering, lose coordination, and have a lowered alertness. These effects can be very dangerous when driving, even though you’re technically below the legal limit.
At four drinks, a person usually reaches the legal limit of .08%, at which point concentration, perception, and information processing will be affected. Five drinks brings a person to .10%, while seven drinks usually cause BAC to elevate to .15%. Impairment is pretty severe in this case, as vomiting, loss of muscle control, and loss of balance are all likely to occur.