What is the significance of the legal BAC limit for drivers over 21?

• A. A BAC exceeding 0.08 is allowed
• B. A BAC exceeding 0.08 has no legal consequences
• C. A driver over 21 with BAC > 0.08 is charged with DWI
• D. A BAC exceeding 0.08 only affects commercial drivers

Answer: (C)

The main idea here is that 0.08% BAC is the legal impairment threshold for drivers over 21. When a person’s blood alcohol concentration rises above this level, driving is treated as impaired by the law, and the driver can be charged with DWI (Driving While Intoxicated) or DUI, depending on the jurisdiction. This threshold isn’t about how drunk someone feels; it’s a measurable standard prosecutors and courts use to determine criminal liability for impaired driving. The significance is practical: it guides enforcement, informs penalties such as fines, license suspension, or jail time, and reinforces the safety message that operating a vehicle with this level of alcohol in the bloodstream is illegal.

The other statements don’t fit because the limit isn’t something that allows driving, and there are consequences for exceeding it. It’s not exclusive to commercial drivers—non-commercial drivers over 21 are also held to this limit (and commercial drivers often have a different, lower standard).