Maryland Transportation Section 21-1105

      (a)      A person may not open the door of a motor vehicle on any side available to moving traffic unless:

            (1)      It is reasonably safe to do so; and

            (2)      It can be done without interfering with the movement of other traffic.

      (b)      A person may not leave a door open on any side of a vehicle available to moving traffic for any period longer than necessary to load or unload passengers.