In North Carolina, a person can be convicted of driving while impaired (DWI) if their blood alcohol concentration (BAC) is .08% or higher or if they are under the influence of alcohol or drugs. A DWI is a drunk driving conviction is above the state legal alcohol limit, rendering the driver legally impaired. Legal limit in North Carolina: Standard, non-commercial drivers: .08% BAC Commercial drivers: .04% BAC Drivers under 21: 0.0% BAC (zero tolerance) Penalties, Fines, & Suspension North Carolina DUI & DWI Penalties, Fines,