Final answer:
Even at BAC levels as low as 0.03-0.04%, drivers may experience reduced visual acuity, slower reaction times, reduced coordination, and diminished judgment. The Field Sobriety Test assesses these impairments, which involve the cerebellum, a brain region sensitive to alcohol.
Step-by-step explanation:
With BAC levels as low as 0.03-0.04%, research has shown that even small amounts of alcohol can have an effect on driving skills. These levels are below the legal intoxication level in the United States, which is 0.08%, but can still lead to impairments. At these low BAC levels, drivers may experience a decrease in visual acuity, slower reaction times, reduced coordination, and diminished judgment.
The Field Sobriety Test (FST) is commonly used by law enforcement to assess these impairments. Because the cerebellum is sensitive to ethanol, an active component of alcohol, it affects coordinated movements and balance, both crucial for safe driving. It's important to understand that these effects can start with very low levels of alcohol consumption and can worsen rapidly as BAC increases.