What is the typical legal BAC limit for drivers age 21 and over?

• A. 0.00% is illegal
• B. 0.10% or higher is illegal; impairment begins at 0.10
• C. 0.08% or higher is illegal; impairment can begin below this level
• D. 0.08% or higher is illegal; impairment can begin below this level

Answer: (D)

For drivers 21 and over, the standard legal limit is 0.08% BAC. Reaching or exceeding 0.08% makes driving illegal, because at that level your ability to operate a vehicle safely is officially considered impaired. But impairment can begin before hitting 0.08%—many people experience slower reaction times, poorer coordination, and poorer judgment at lower BAC levels. So the statement that 0.08% or higher is illegal, while impairment can begin below this level, captures both the legal threshold and the reality that impairment can occur earlier.