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 Oregon, it is indeed a criminal offense for a commercial vehicle operator to have a blood alcohol concentration (BAC) of .04 or higher, which is stricter than the .08 BAC limit for non-commercial drivers. This is in accordance with federal regulations that apply to all states. For holders of a Commercial Driver's License (CDL), the consequences of a DUI (Driving Under the Influence) conviction can be severe, especially considering their reliance on their license for employment. Under Oregon law, a first-time DUI conviction for a CDL holder can result in a one-year disqualification from operating a commercial vehicle. If a CDL holder is convicted of a second DUI, either in a commercial or non-commercial vehicle, they face a lifetime disqualification from holding a CDL, which may be reduced to 10 years under certain conditions. These regulations are designed to promote safety on the roads and ensure that commercial vehicle operators adhere to strict standards of sobriety. The relevant laws can be found in Oregon's vehicle or transportation codes.