Maryland Transportation Section 21-1101

      (a)      Except as provided in subsection (c) of this section, a person driving or otherwise in charge of a motor vehicle may not leave it unattended until the engine is stopped, the ignition locked, the key removed, and the brake effectively set.

      (b)      A person driving or otherwise in charge of a motor vehicle may not leave the motor vehicle unattended until, if the vehicle is on a grade, the front wheels are turned to the curb or side of the highway.

      (c)      When a cat or dog is left in the unattended vehicle of an on-duty law enforcement officer or an animal control officer, the provisions of subsection (a) of this section do not apply to the law enforcement officer or the animal control officer.