Driving under the influence (DUI) under Florida Statute § 316.193 means driving or being in actual physical control of a vehicle while impaired by alcohol, drugs, or both, or with a breath/blood alcohol level of 0.08 or higher. A first DUI carries fines from $500 to $1,000, up to six months in jail, a 180-day license revocation, and mandatory ignition interlock in some cases; enhanced penalties apply for high breath results, minors in the vehicle, or prior convictions. Defenses attack the traffic stop, field sobriety exercises, breath-test machine maintenance records, and observed impairment.