Maryland Transportation Section 22-218
(a)   Every emergency vehicle, in addition to any other equipment and distinctive markings required by this subtitle, shall be equipped with a siren, exhaust whistle, or bell capable of giving an audible signal.
(b)   (1)   Every emergency vehicle, in addition to any other equipment and distinctive markings required by the Maryland Vehicle Law, shall be equipped with signal lamps mounted as high as practicable, which shall be capable of displaying to the front and to the rear a flashing red light or lights. These lights shall have sufficient intensity to be visible at 500 feet in normal sunlight.
(2)   Every school vehicle meeting the requirements established by the Administrator shall be equipped with alternately flashing warning lights in accordance with the standards adopted under § 22-228 of this subtitle.
(c)   (1)   A person may not drive or move on any highway any vehicle or equipment that is equipped with or displays any light or signal device designed to emit an oscillating, rotating, blinking, or other type of emission of light, unless designated and authorized by the Administrator as indicated in paragraphs (2) through (10) of this subsection. The provisions of this section do not prohibit the display and use of any lighting device that may be permitted or required elsewhere in the Maryland Vehicle Law.
(2)   Vehicles of the police department and other city, county, State, or federal law enforcement agencies may be equipped with and display red, white, or blue lights or signal devices.
(3)   (i)   Vehicles of city, county, State, or federal fire departments or duly constituted volunteer fire departments or rescue squads, or the Maryland Institute for Emergency Medical Services System, may be equipped with or display red and/or white lights or signal devices.
(ii)   In each volunteer fire company, no more than five of the following officers may have their privately owned vehicles equipped with red lights or signal devices which may be displayed only while on route to or at the scene of an emergency:
1.   The fire chief or the highest ranking fireline officer;
2.   One or more of the assistant chiefs or deputy chiefs, whichever rank is second in command; and
3.   The emergency medical services commander.
(iii)   1.   The fire police of each volunteer fire company may have their privately owned vehicles equipped with red lights or signal devices designed to emit an oscillating, rotating, blinking, or other type of emission of light.
2.   The lights or signal devices may be flashed or oscillated or otherwise used only while the vehicle is at the scene of an accident, flood, or other emergency to which the volunteer fire company is responding.
(4)   Ambulances may be equipped with or display red and/or white lights or signal devices.
(5)   State vehicles used in response to oil or hazardous materials spills may be equipped with or display red and/or white lights or signal devices.
(6)   Service vehicles, rural letter carrier vehicles, slow moving farm vehicles, and tow trucks may be equipped with or display yellow or amber lights or signal devices.
(7)   State vehicles designated for emergency use by the Commissioner of Correction may be equipped with or display red lights or signal devices.
(8)   (i)   Except as provided in subparagraphs (ii) and (iii) of this paragraph, the blue, red, or white lights or signal devices may be flashed or oscillated or otherwise used only while on route to or at the scene of an emergency, and their use does not relieve an emergency vehicle from otherwise giving an audible warning as required elsewhere in the Maryland Vehicle Law.
(ii)   The driver of an emergency vehicle may use flashing lights within 100 feet of the entrance ramp of a fire or rescue station while parking or backing the emergency vehicle.
(iii)   The driver of an emergency vehicle of a fire department or rescue squad shall, at the discretion of the officer in charge, flash or oscillate or otherwise use red and white lights or signal devices while stopped, standing, or parked on the roadway at the scene of an emergency.
(9)   The yellow or amber lights or signal devices permitted on vehicles under paragraph (6) of this subsection may be flashed or oscillated or otherwise used only in the course of official duties, to indicate to the public that the vehicle is a slow moving vehicle or otherwise is impeding traffic.
(10)   (i)   An emergency vehicle of any foreign state may be equipped with any lights or signals:
1.   As provided by this subsection; or
2.   As permitted by the state in which the vehicle is registered.
(ii)   1.   The use of any lights or signals permitted under this paragraph is limited to an emergency vehicle, as defined in § 11-118 of this article, responding to an emergency or pursuing a violator, and equipped with an audible signal as provided in this section.
2.   Foreign vehicles, as defined in § 11-124 of this article, which are privately owned by members of volunteer fire companies, ambulance or rescue squads, fire departments, and law enforcement agencies may be equipped with lights or signals as permitted by the state in which the vehicle is registered, but such lights or signals may be used while the vehicle is in this State only by those personnel and under the circumstances authorized under paragraph (3) of this subsection.
(iii)   In addition to the penalties provided in Title 27 of this article, any person convicted of a violation of this section may have his driving privileges suspended for a period of 30 days, and the registration of the vehicle may be suspended for a period of 30 days, notwithstanding that the owner of the vehicle may not be the operator at the time of the offense, unless the owner proves to the satisfaction of the Administration that he had no control over the use or display of a light or signal device and could not prevent the violation of this section.
(d)   A police vehicle when used as an emergency vehicle may, but need not be, equipped with the flashing red and/or blue lights specified in this section.
(e)   Except as provided in subsection (c)(3) of this section, the flashing lighting described in subsections (b) and (c) of this section may not be used on any vehicle other than an emergency vehicle, service vehicle, or school vehicle.
(f)   The use of the signal equipment described in this section imposes on drivers of other vehicles the obligation to yield the right-of-way and stop as required in Title 21 of this article.
(g)   On taxicabs, the flashing green lights known as emergency hold-up lights may be mounted on the roof or outside rear and front of the vehicle.