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 North Carolina, it is indeed a criminal offense for a commercial vehicle operator to have a blood alcohol concentration (BAC) of .04 or more, which is indeed half the BAC limit for drivers of non-commercial vehicles. For holders of a Commercial Driver's License (CDL), the consequences of a DUI/DWI are particularly severe due to their reliance on their license for employment. Under North Carolina law, a first offense DUI/DWI can result in a one-year suspension of the CDL. If a CDL holder commits a second DUI/DWI, they face the possibility of being permanently disqualified from holding a CDL. These regulations are designed to promote safety on the roads and ensure that commercial vehicle operators adhere to stricter standards due to the potential risks associated with the operation of larger vehicles. The relevant laws can be found in the state's General Statutes, specifically within the chapters dealing with motor vehicles and transportation.