What is the maximum blood alcohol concentration (BAC) allowed for a CDL driver operating a commercial vehicle?

Answer: B — 0.04%

The maximum blood alcohol concentration (BAC) allowed for a CDL driver operating a commercial vehicle is 0.04%. This limit is set by federal regulations to ensure safety on the roads, recognizing that commercial drivers are responsible for larger, potentially more dangerous vehicles and may be carrying passengers or hazardous materials. At this BAC level, drivers are considered legally impaired, and operating a vehicle while impaired greatly increases the risk of accidents. The lower permissible level for commercial drivers, compared to the general limit of 0.08% for non-commercial drivers, reflects the heightened responsibility that comes with driving a commercial vehicle. Therefore, maintaining a BAC below 0.04% is critical for the safety of the driver, passengers, and other road users.