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 Minnesota, it is indeed a criminal offense for a commercial vehicle operator to have a blood alcohol concentration (BAC) of .04 or more, which is stricter than the .08 BAC limit for non-commercial drivers. This is in accordance with Minnesota Statute 169A.20, which governs driving while impaired (DWI) offenses. For holders of a Commercial Driver's License (CDL), the consequences of a DWI conviction can be particularly severe. A first-time DWI offense while operating any vehicle can result in a one-year disqualification of the CDL. If the offense involves hazardous materials transportation, the disqualification period is three years. A second DWI conviction, under Minnesota Statute 171.165, can lead to a lifetime disqualification, which may be reduced to 10 years under certain conditions. These penalties reflect the high standards of safety expected from commercial drivers, given the potential risks associated with commercial vehicle operation.