Chapter 4: DUI / DWI Laws

Driving while intoxicated (DWI) is one of the most dangerous and reckless decisions a person can make. Impaired driving kills thousands of people every year and leads to devastating, life-altering legal and financial consequences for the offender. Understanding Louisiana’s strict DWI laws is critical for your safety, the safety of others, and for passing your knowledge exam, which heavily emphasizes the gravity of this offense.

DUI & Implied Consent

In Louisiana, the offense of operating a vehicle while impaired is known as Driving While Intoxicated (DWI). This is a serious crime with severe penalties. A driver can be arrested for DWI if their ability to operate a vehicle is impaired by alcohol, any controlled dangerous substance (including illegal drugs like marijuana or cocaine), or a combination of substances. This also includes prescription and over-the-counter medications if they cause impairment that affects driving ability.

Blood Alcohol Concentration (BAC) Limits

The primary way intoxication is measured is through Blood Alcohol Concentration (BAC), which is the percentage of alcohol in the bloodstream. Louisiana law establishes “per se” BAC limits, meaning that if a driver’s BAC is at or above these levels, they are considered legally intoxicated without needing any further proof of impairment.

• 21 Years of Age or Older: The legal BAC limit is 0.08%.
• Under 21 Years of Age: Louisiana has a “Zero Tolerance” law. The legal BAC limit is 0.02%. Any measurable amount of alcohol can lead to a DWI charge.
• Commercial Drivers: For drivers operating a commercial vehicle, the legal BAC limit is 0.04%.