Final answer:
The legal blood alcohol content limit for drivers above the age of 21 in the U.S. is 0.08%. Factors such as metabolism can affect one's BAC level, but the legal limit remains as a benchmark for DUI offenses.
Step-by-step explanation:
The legal limit of blood alcohol content (BAC) for a driver above 21 years of age in the United States is 0.08%. Driving with a BAC at or above this limit is considered illegal and may result in a charge of Driving Under the Influence (DUI). The body metabolizes alcohol at a consistent rate, but it's important to note that factors such as weight, sex, and individual metabolism can affect BAC levels. Therefore, while one may not necessarily feel intoxicated, they could still be legally impaired. Always practicing responsible drinking habits, understanding the effects of alcohol on the body, and recognizing the legal implications are key to safety on the road.