Maryland Transportation Section 16-813

      (a)      An individual may not drive, operate, or be in physical control of a commercial motor vehicle while the individual has any alcohol concentration in the individual's blood or breath.

      (b)      A person who drives, operates, or is in physical control of a commercial motor vehicle while having alcohol in the person's system or who, subject to § 16-205.1 of this title, refuses to take a chemical test to determine the alcohol concentration, shall be placed out-of-service for the 24-hour period immediately following the time the police officer or employer detects alcohol in the driver's blood or breath.