If you’re pulled over under the suspicion of drunk driving, a breathalyzer will most likely be administered. Breathalyzers measures your blood alcohol content (BAC) to determine whether you’re over the legal driving limit of .08%. The Centers for Disease Control and Prevention explains how BAC correlates to your level of inebriation.
Standard drink sizes typically depend on what you’re drinking and how potent it is. Standard sizes for wine and liquor are smaller because those types of alcohol are more potent. For example, 12-ounces of beer is one standard drink, as is 5-ounces of wine because wine has a higher alcohol content than beer. Each standard-sized drink you consume increases your BAC. Additionally, you begin to feel effects from the alcohol well before you reach the legal limit.
When your BAC is .02%, which typically occurs after two standard drinks, you’ll experience a feeling of relaxation and a slightly elevated mood. You’ll also find difficulty multitasking, which is an important ability to have when operating a vehicle. Another drink and your BAC will have reached .05%. Muscle control, judgment, and coordination will all be impaired at this point. With one more drink, you’ll have reached the legal limit of .08%.
Along with the above impairments, by .08% you’ll also experience loss of short-term memory, an inability to regulate your speed, and problems perceiving the world around you. Seven drinks means a .15% BAC, at which point significant impairments are known to occur. While the above guide is largely considered accurate, factors like weight and gender can also have an impact on BAC. It’s also possible to have a false positive reading if breathalyzers are improperly maintained or calibrated.