In many states it is a criminal offense (DUI/DWI) to operate a commercial vehicle with a blood alcohol concentration of .04 or more—which is half of the BAC usually required to commit the DUI/DWI offense while driving a non-commercial vehicle. Because most holders of commercial driver’s licenses (CDLs) depend on their license to earn a living, the consequences of a DUI/DWI conviction for a CDL holder—including a conviction while operating a non-commercial vehicle—are serious.

Laws vary from state to state but a CDL holder’s license may be suspended for one year for the first offense, and with a second DUI/DWI conviction the CDL holder may be permanently disqualified from holding a CDL.

These laws are generally located in a state’s statutes—often in the vehicle code, motor vehicle code, or transportation code.

In Florida, it is indeed a criminal offense for a commercial vehicle operator to have a blood alcohol concentration (BAC) of .04 or higher, which is half the BAC limit of .08 for drivers of non-commercial vehicles. For holders of a Commercial Driver's License (CDL), the consequences of a DUI (Driving Under the Influence) conviction can be particularly severe, given their reliance on their license for employment. Under Florida law, a first-time DUI offense for a CDL holder can result in a one-year suspension of their CDL. If a CDL holder is convicted of a second DUI, they face permanent disqualification from holding a CDL. These regulations are part of Florida's statutes, which can be found in the state's vehicle or transportation codes.