A person’s blood alcohol concentration (BAC) is a key factor when determining whether they are driving under the influence. BACs of .08% or greater will lead to an arrest, but it is important to understand that you feel the effects of inebriation well before you reach this stage. Here is how BAC corresponds to the number of drinks and your level of impairment.
Understanding the standard drink size
Not everyone gets drunk at the same rate. For example, a person who is substantially larger would naturally take longer to become impaired. Additionally, certain types of alcohol are stronger than others, which also has an impact on BAC. That is why standard drink sizes differ depending on what you are drinking.
Because beer has 5% alcohol content, 12-ounces is considered a standard drink. Conversely, a shot of liquor has 40% alcohol content, so a standard drink size is much smaller at 1.5-ounces. Wine has 12% alcohol content, so a standard glass of wine is about 5-ounces.
BAC vs. number of drinks
After your first two drinks, your BAC will about .02%. While this is well under the legal limit, you will experience things like loss of judgment, an inability to multi-task, and problems with visual functioning. If you have two more drinks, your BAC will be .08%. At this point, reaction time, hand-eye coordination, and reasoning will all be impaired.
Three more drinks and your BAC will be .15%. It is extremely dangerous to drive after this many drinks, as you will experience substantial impairment that could jeopardize your safety and the safety of others. You will have less control over your muscles, your balance will be compromised, and it will be increasingly difficult to pay attention to the road.