MD TRANSPORTATION CODE § 21-402 (2010) is Maryland's left turn law:
§ 21-402. Vehicle turning left or making U-turn
(a) Turning left. - If the driver of a vehicle intends to turn to the left in an intersection or into an alley or a private road or driveway, the driver shall yield the right-of-way to any other vehicle that is approaching from the opposite direction and is in the intersection or so near to it as to be an immediate danger.
(b) U-turn. - If the driver of a vehicle intends to turn to go in the opposite direction, the driver shall yield the right-of-way to any approaching vehicle that is so near as to be an immediate danger.