From the New York State Vehicle and Traffic Law Section 375 (41) 4 a b c
4. Blue light. a. One blue light may be affixed to any motor vehicle owned by a volunteer member of a fire department or on a motor vehicle owned by a member of such person's family residing in the same household or by a business enterprise in which such person has a proprietary interest or by which he or she is employed, provided such volunteer firefighter has been authorized in writing to so affix a blue light by the chief of the fire department or company of which he or she is a member, which authorization shall be subject to revocation at any time by the chief who issued the same or his or her successor in office. Such blue light may be displayed exclusively by such volunteer firefighter on such a vehicle only when engaged in an emergency operation. The use of blue lights on vehicles shall be restricted for use only by a volunteer firefighter except as otherwise provided for in subparagraph b of this paragraph.
b. In addition to the red and white lights authorized to be displayed pursuant to paragraph two of this subdivision, one or more blue lights or combination blue and red lights or combination blue, red and white lights may be affixed to a police vehicle, fire vehicle, ambulance, emergency ambulance service vehicle, and county emergency medical services vehicle provided that such blue light or lights shall be displayed on a police vehicle, fire vehicle, ambulance, emergency ambulance service vehicle, and county emergency medical services vehicle for rear projection only. In the event that the trunk or rear gate of a police vehicle, fire vehicle, ambulance, emergency ambulance service vehicle, and county emergency medical services vehicle obstructs or diminishes the visibility of other emergency lighting on such vehicles, a blue light may be affixed to and displayed from the trunk, rear gate or interior of such vehicles. Such lights may be displayed on a police vehicle, fire vehicle, ambulance, emergency ambulance service vehicle, and county emergency medical services vehicle when such vehicles are engaged in an emergency operation. Nothing contained in this subparagraph shall be deemed to authorize the use of blue lights on police vehicles, fire vehicles, ambulances, emergency ambulance service vehicles, and county emergency medical services vehicles unless such vehicles also display one or more red or combination red and white lights as otherwise authorized in this subdivision.
c. The commissioner is authorized to promulgate rules and regulations relating to the use, placement, power and display of blue lights on a police vehicle and fire vehicle.
