What indicator do most states use to determine if a person is intoxicated?

Most states use blood-alcohol level as the primary indicator to determine if a person is legally intoxicated. This measurement provides a quantifiable and objective assessment of how much alcohol is in a person's bloodstream. The legal limit for blood alcohol concentration (BAC) varies by state, but typically, a BAC of 0.08% or higher is considered intoxicated for drivers over the age of 21.

Using blood-alcohol level as a metric is effective because it accounts for the differences in individual tolerance and body composition, which can influence how alcohol affects a person. This standardization helps law enforcement and the judicial system establish clear guidelines for evaluating intoxication and related offenses.

While other indicators such as slurred speech, poor motor coordination, and the number of drinks consumed may suggest intoxication, they are subjective and can vary widely between individuals. Additionally, these factors alone do not provide a clear or reliable measure for legal intoxication, which is why blood-alcohol level is preferred for legal and safety purposes.