Final answer:
The legal BAC limit for drivers under the age of 21 in the U.S. is 0.02%. This lower limit aims to discourage underage drinking and driving, keeping in mind that alcohol impairs driving abilities. Tolerance to alcohol and metabolism rates can vary, thus enforcement of this low BAC is crucial for safety.Option 1 is the correct answer.
Step-by-step explanation:
The legal limit of blood alcohol content (BAC) for drivers under the age of 21 in the United States is 0.02%. This is significantly lower than the standard legal limit for adults 21 and over, which is set at 0.08%. The reason for the lower BAC limit for underage drivers is due to the National Minimum Drinking Age Act of 1984, which aimed to reduce alcohol consumption among minors and the associated risks, particularly while driving. Despite the metabolism rate of alcohol (about 3.3 mmol/L or 15 mg/dL per hour), for safety reasons, the limit is kept low to discourage any alcohol consumption before driving.
The enforcement of this limit is critical to public safety, as alcohol can significantly impair driving abilities. Diagnosis of intoxication is often based on physical examination and can be verified with a breathalyzer test, which measures the ethanol concentration in breath, correlated to BAC. It is also important to note that tolerance and alcohol metabolism can vary among individuals, and some may feel the effects of alcohol with even lower levels of BAC.