Final answer:
The legal BAC limit for individuals over 21 in Alabama is 0.08%. This threshold is standardized in most states as a result of federals laws relating to highway funding and the minimum drinking age.
Step-by-step explanation:
The legal limit of BAC (Blood Alcohol Concentration) for someone OVER 21 in the state of Alabama is 0.08%. This limit is consistent across most US states due to the influence of the National Minimum Drinking Age Act of 1984, which tied federal highway funds to states maintaining a minimum drinking age of twenty-one.
It's important to understand that different BAC levels can have various effects on the body, and the way alcohol affects each individual can vary considerably depending on factors such as age, sex, and health condition. For safe and legal driving in Alabama, and the wider United States, it's crucial for those over the age of 21 to be aware of this limit and to ensure they do not exceed it when behind the wheel.