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 Pennsylvania, 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. For holders of a Commercial Driver's License (CDL), the consequences of a DUI/DWI are particularly severe. Under Pennsylvania law, a first-time DUI offense for a CDL holder can result in a one-year suspension of their CDL. If the CDL holder commits a second DUI/DWI, they face a lifetime disqualification from holding a CDL, with the possibility of reinstatement after 10 years under certain conditions. These regulations are designed to ensure the safety of the roads and reflect the higher standards of professionalism expected from commercial drivers. The relevant laws can be found in the Pennsylvania Vehicle Code, specifically in Title 75 of the Pennsylvania Consolidated Statutes.