Maryland Transportation Section 22-405.5
§ 22-405.5.
  (a)   A person may not sell or offer for sale, at the point of final retail sale to the consumer, an unsafe tire, for use on a highway, that does not meet or exceed the requirements set forth in subsection (b) of this section or in regulations promulgated under § 22-405(c) of this article.
  (b)   A tire shall be considered unsafe if it:
    (1)   Has tread wear indicators and the tire is worn to the point that the tread wear indicators are flush with the tread at any place on the tire;
    (2)   Does not have tread wear indicators and the tire is worn so that less than 2/32 of an inch tread remains when measured in any groove at three locations spaced approximately equally around the outside of the tire; provided that motorcycle tires shall be allowed to be worn down to 1/32 of an inch, if measured under this paragraph;
    (3)   Has a worn spot that exposes the cord through the tread;
    (4)   Has tread cuts, snags, or sidewall cracks in any direction which are deep enough to expose body cords;
    (5)   Has visible bumps, bulges, or knots indicating partial failure or separation of the tire structure;
    (6)   Has unrepaired fabric breaks or the sidewall has damaged body cords;
    (7)   Has been regrooved or recut except as authorized in § 22-405.1; or
    (8)   Is marked:
      (i)   For farm use only;
      (ii)   For off-highway use only; or
      (iii)   For racing use only.
  (c)   A tire failing to meet the requirements of subsection (b) of this section may be sold for off-highway use only if the tire has permanently inscribed on its sidewall the letters "OH" at least 3/4 of an inch in height.