Chapter 4: DUI / DWI Laws

Driving under the influence of alcohol or drugs is one of the most dangerous decisions a driver can make, leading to thousands of preventable deaths and injuries each year. South Carolina has strict laws and severe penalties to combat impaired driving, and understanding them is a non-negotiable part of being a responsible driver. This knowledge is critical for passing your license exam and, more importantly, for making choices that protect your life, your future, and the lives of everyone else on the road.

DUI & Implied Consent

In South Carolina, it is illegal to operate a motor vehicle while under the influence of alcohol, drugs (including prescription and over-the-counter medications), or a combination of substances to the extent that your faculties to drive are materially and appreciably impaired. The state has two primary offenses: Driving Under the Influence (DUI) and Driving with an Unlawful Alcohol Concentration (DUAC).

• DUI: This charge requires the prosecution to prove that a driver’s ability to operate a vehicle was significantly impaired by a substance.
• DUAC: This is a “per se” offense, meaning the prosecution only needs to prove that the driver’s Blood Alcohol Concentration (BAC) was at or above the legal limit. No further proof of impairment is necessary for a conviction.

Blood Alcohol Concentration (BAC) Limits

BAC is the percentage of alcohol in a person’s bloodstream. The legal limits are set by law and vary by age and license type.

• 21 or Older: It is illegal to drive with a BAC of 0.08% or higher.
• Under 21 (Zero Tolerance Law): It is illegal for a person under the age of 21 to drive with a BAC of 0.02% or higher. This low threshold means that even one drink can put a young driver over the legal limit.
• Commercial Drivers (CDL): It is illegal to operate a commercial vehicle with a BAC of 0.04% or higher.