Final answer:
BAC stands for Blood Alcohol Concentration, which is the measure of alcohol in a person's bloodstream used to determine legal impairment in DUI cases, typically tested by a Breathalyzer or blood test.
Step-by-step explanation:
In the context of law enforcement and driving under the influence, the initials BAC stand for Blood Alcohol Concentration. This is a measure of the amount of alcohol present in a person’s bloodstream and is typically expressed as a percentage by volume. For example, a BAC of 0.08% means that there are 0.08 grams of alcohol per 100 mL of blood. In many jurisdictions, a person is considered legally impaired with a BAC of 0.08% or higher. The Breathalyzer is a widely used device to estimate a person's BAC by measuring the amount of alcohol in their breath. Factors such as age, sex, body weight, and individual metabolism can affect a person's BAC, making its effects differ widely between individuals.
Field Sobriety Tests (FST) are also used to determine if a driver is under the influence, and these tests often rely on the assessment of physical coordination and balance, as alcohol notably affects the cerebellum, which is essential for these functions. While BAC levels can be determined through both blood and breath testing, BAC provides a more direct and quantifiable measure of intoxication, and as such, it's commonly used by law enforcement agencies to enforce DUI laws.