Maryland Code, Transportation § 22-227

(a) During the times specified in § 22-201.1 of this subtitle, any lighted lamp or illuminating device on a motor vehicle (other than headlamps, spot lamps, auxiliary lamps, flashing turn signals, emergency vehicle and service vehicle warning lamps, and school vehicle warning lamps) that projects a beam of light of an intensity greater than 300 candlepower shall be so directed that no part of the high-intensity portion of the beam will strike the level of the roadway on which the vehicle stands at a distance of more than 75 feet from the vehicle.

(b) Except as required or permitted in § 22-218 of this subtitle or in the rules governing the operation of emergency vehicles and school vehicles, a person may not drive or move any vehicle or equipment on any highway with any lamp or device on it that displays a red or blue light visible from directly in front of its center.

(c) Flashing lights are prohibited except as required or permitted in the Maryland Vehicle Law.  1

(d) Except as authorized elsewhere in this subtitle, a person may not drive or move any vehicle or equipment on any highway with any lamp or device on it that displays a white light visible directly from its rear.

(e) Except as authorized elsewhere in this subtitle, a person may not drive or move any vehicle or equipment on any highway while the vehicle or equipment displays any flashing light.

(f) All lighting devices and reflectors mounted on the rear of any vehicle shall display or reflect a red color, except the turn signal and hazard warning lamps, which may be red, amber, or yellow, and except that the light illuminating the registration plate shall be white and the light emitted by a backup lamp shall be white.