Md. Code, Transportation § 14–101

(a) This title does not apply to the following:

(1) A vehicle moved only by human or animal power; or

(2) A self-propelled invalid:

(i) Wheelchair; or

(ii) Tricycle.

(b) This title does not apply to the following unless a certificate of title has been issued for them under Title 13 of this article:

(1) Any farm equipment; or

(2) Any special mobile equipment.