This chapter pertains to the nature, display, color, minimum performance standards and configuration of flashing or revolving lights that are permissible for display by emergency and authorized vehicles.

 The following words and terms, when used in this chapter, have the following meanings, unless the context clearly indicates otherwise:

   Authorized vehicle�The term as defined in 75 Pa.C.S. §  102 (relating to definitions).

   Emergency vehicle�The term as defined in 75 Pa.C.S. §  102.

   Flash�An intermittent burst of light.

   Flash rate�The rate of flash, revolution or oscillation per minute of a single light, when that light is observed from a fixed position.

   Flashing headlamp system�A system designed to automatically flash the high intensity�high beam�portion of the headlamps of a vehicle in either an alternate or simultaneous flash. The system shall be designed so that activation of the high intensity�high beam�portion of the standard headlamp system overrides the flashing headlamp system.

   Flashing light�A light designed to flash by current interruption, oscillation of the lamp or current, or by revolution of the lamp.

   Hazard warning system�Driver-controlled flashing front and rear lights used to warn approaching motorists when a vehicle is broken down or is traveling at a slow speed.

   Intersection light�A flashing red light device, mounted on the upper portion of each front fender of an emergency vehicle, and used as a part of the flashing or revolving light system to enhance the visibility of an emergency vehicle as it approaches or travels through an intersection.

   Light activation indicator�An audible signal or an illuminated switch or pilot light which provides the driver of an emergency or authorized vehicle with a clearly audible or visible and continual indicator that a flashing or revolving light, flashing headlamp system, traffic control emergency directional light, or authorized nonflashing or nonrevolving light is activated.

   Light-bar assembly�A device designed and constructed to provide and display more than one steady burning, flashing or revolving beam of light.

   Oscillation�ovement back and forth between two points, including the alternation between the maximum and minimum voltage.

   Revolving light�A light designed to give the appearance of flashing by its rotation around a fixed axis through a 360° arc, on a horizontal plane.

   Single light�A device containing one or more lenses, lamps or bulbs which are designed to produce, when viewed from a fixed position or point, the appearance of one flashing or revolving beam of light.

   Traffic control emergency directional light assembly�A device electronically designed to display amber or yellow warning signal lights in a distinctive motion-lighting pattern�arrow left, arrow right, center out or alternately flashing�to warn motorists that they are approaching a hazard or to direct them around an impending hazard.

 (a)  Color. White, clear, red, blue, amber or yellow are the only colors permitted for use in flashing or revolving lights.

   (1)  Chromaticity coordinates. A flashing or revolving light shall comply with the Chromaticity Coordinates, CIE 1931, Standard Colorimetric System as provided in SAE Standard J578d, Color Specification for Electrical Signal Lighting Devices, September 1978. This requirement does not apply to flashing headlamp systems.

   (2)  Red lights. A vehicle may display red lights as follows:

     (i)   Under 75 Pa.C.S. §  4571 (relating to visual and audible signals on emergency vehicles), an emergency vehicle, as defined in 75 Pa.C.S. §  102 (relating to definitions), shall be equipped with one or more flashing or revolving red lights.

     (ii)   Under 75 Pa.C.S. §  4571, Pennsylvania Public Utility Commission vehicles used for the enforcement of 66 Pa.C.S. Chapters 23 and 25 (relating to common carriers; and contract carrier by motor vehicle and broker) may be equipped with flashing or revolving red lights.

   (3)  Blue lights. Under 75 Pa.C.S. §  4572(a) (relating to visual signals on authorized vehicles), ambulance personnel, owners and handlers of dogs used in tracking humans, and volunteer firefighters may each equip one personal vehicle with no more than two flashing or revolving blue lights or one light-bar assembly containing no more than two blue lights. Only blue lights may be used on the light-bar assembly. See Figure 3.1.

   (4)  Combination red-and-blue lights. Under 75 Pa.C.S. §  4571(b), police, sheriff, coroner, medical examiner or fire police vehicles may be equipped with flashing or revolving blue lights in addition to red lights�combination red-and-blue lights. The privately-owned vehicles of a police chief, assistant police chief, fire police captain and fire police lieutenant shall be equipped under paragraph (2).

   (5)  Yellow or amber lights. A vehicle may display yellow or amber lights as follows:

     (i)   Under 75 Pa.C.S. §  4572(b), an authorized vehicle as defined in 75 Pa.C.S. §  102 and designated in Chapter 15 (relating to authorized vehicles and special operating privileges) may be equipped with no more than two flashing or revolving yellow or amber lights or one light-bar assembly containing no more than two yellow or amber lights. Only yellow or amber lights may be used on the light-bar assembly.

     (ii) Emergency vehicles may be equipped with no more than two yellow or amber lights, in addition to one traffic control emergency directional light assembly.

   (6)  White or clear lights. In addition to flashing or revolving red or combination red-and-blue lights, an emergency vehicle may be equipped with a flashing headlamp system and no more than one flashing or revolving white or clear light, except that an emergency vehicle may be equipped with a light-bar assembly containing no more than two flashing or revolving white or clear lights.

     (i)   Flashing or revolving white or clear lights and flashing headlamp systems may only be used in conjunction with the flashing or revolving red or combination red-and-blue lights. Flashing or revolving white or clear lights and flashing headlamp systems that are not used in conjunction with flashing or revolving red or combination red-and-blue lights do not constitute visual signals under 75 Pa.C.S. § §  3325 and 4571 (relating to duty of driver on approach of emergency vehicle; and visual and audible signals on emergency vehicles).

     (ii)   Flashing headlamp systems are to be used under 75 Pa.C.S. §  4306 (relating to use of multiple-beam road lighting equipment).

   (7)  Steady burning lights. Unauthorized colored, white or clear nonflashing or nonrevolving lights�steady burning lights�may not be used in conjunction with flashing or revolving lights, except for steady burning lights used on emergency vehicles as specified in 75 Pa.C.S. §  4571(a) and (b)(3). These lights, which include flood lights and other steady burning lights, may be used only while the vehicle is stationary, except that a police officer, sheriff or deputy sheriff operating a police or sheriff vehicle may use these lights while the vehicle is in motion, if the lights are used only for the purpose of an emergency, or for the safety of the public or in the enforcement of the law.

   (8)  Other lights. A vehicle, other than those identified in this subsection, may not be equipped with lights or systems identical or similar to those specified by this subsection, except that school buses and urban mass transit buses which will be used for carrying school children may be equipped with flashing lights as permitted by 75 Pa.C.S. § §  4552(b) and 4553(a) (relating to general requirements for school buses; and general requirements for other vehicles transporting school children), and Chapter 15 and Chapter 171 (relating to school buses and school vehicles).

   (9)  Hazard warning systems and turn signals. Hazard warning systems and turn signals are not considered flashing lights for the purposes of this chapter.

 (b)  360° visibility. When flashing or revolving red, blue, yellow or amber lights are mounted on a vehicle, one or more of these lights shall be mounted to provide visibility to vehicles approaching from any direction (360° visibility), regardless of the method of mounting. Emergency vehicles equipped with flashing or revolving red or blue lights mounted on or behind the grille are not exempt from this subsection.

   (1)  When only one light is used to provide 360° visibility, this light shall be in compliance with SAE Standard J845, 360° Emergency Warning Lamps, January 1984.

   (2)  When more than one light is used to provide 360° visibility, the number of lights used may not exceed those specified in 75 Pa.C.S. § §  4571 and 4572.

   (3)  For emergency vehicles, 360° visibility shall be provided by one or more red lights.

   (4)  Vehicles that are equipped with a light-bar assembly are presumed to have met the 360° visibility requirements when the flashing or revolving light configuration is visible to vehicles approaching from any direction.

 (c)  Flash rate. The flash rate, when observed from a fixed position, shall be between 60 and 120 flashes per minute. When the flash rate is produced by the interruption of current, the period of illumination shall be long enough to permit the bulb to come to full brightness.

 (d)  Mounting location. The following applies to mounting locations for flashing or revolving lights:

   (1)  Flashing or revolving lights, excluding flashing headlamp systems, may be permanently mounted on the vehicle or attached to a mounting device, in a workmanlike manner, in the following locations only:

     (i)   On a cab or roof of the vehicle.

     (ii)   No more than 18 inches above the highest fixed point of the vehicle.

     (iii)   On the front of a dump truck bed.

     (iv)   Behind or on the grille of emergency vehicles. A flashing light may not be mounted so that it flashes through the grille, except that no more than two flashing red or blue lights, excluding light-bar assemblies, may be mounted so as to flash through or in front of the grille on emergency vehicles when the vehicle is also equipped with one or more flashing or revolving red lights that meet the 360° visibility requirements of subsection (b).

     (v)   Close to the front upper edge of each front fender of an emergency vehicle and not protruding more than 2 inches from the fender, with respect to intersection lights.

   (2)  Traffic control emergency directional light assemblies shall be rear-facing only and may not interfere with permanently installed lights. These assemblies may be permanently mounted on the vehicle or attached to a mounting device, in a workmanlike manner, in the following locations only:

     (i)   Underneath or behind light-bar assemblies.

     (ii)   On the rear deck, inside or outside of the vehicle.

     (iii)   On the trunk lid.

 (e)  Mounting devices. Flashing or revolving lights, excluding flashing headlamp systems, grille-mounted flashing lights and intersection lights, may be mounted on one of the following devices:

   (1)  A magnetic base.

   (2)  A roof rack, light-bar or other device that is welded or bolted onto the vehicle, or is mounted on the vehicle by using suction cups equipped with nylon or steel straps and clips which hook onto the drip rail or moulding.

   (3)  A self-leveling gimbal device.

   The provisions of this §  173.3 issued under the Vehicle Code, 75 Pa.C.S. § §  4571, 4572 and 6103.

   The provisions of this §  173.3 adopted October 21, 1977, effective October 22, 1977, 7 Pa.B. 3131; amended May 12, 1978, effective May 13, 1978, 8 Pa.B. 1329; amended March 27, 1981, effective March 28, 1981, 11 Pa.B. 1100; amended August 14, 1981, effective August 15, 1981, 11 Pa.B. 2856; amended November 5, 1993, effective November 6, 1993, 23 Pa.B. 5309. Immediately preceding text appears at serial page (132818).

 Wiring shall be permanently installed in the vehicle. Separate fuses shall be utilized for the flashing or revolving light system to prevent failure of the standard lighting equipment of the vehicle if the flashing or revolving lights fail. These requirements do not apply to flashing or revolving lights that are attached to a vehicle with a magnetic base.

 Emergency and authorized vehicles which are equipped with lights or light systems provided for in this chapter shall also be equipped with a light activation indicator which will automatically activate whenever a flashing or revolving light, flashing headlamp system, traffic control emergency directional light or authorized nonflashing or nonrevolving light is engaged.

 A violation of this chapter is a summary offense and subject to sanctions imposed under 75 Pa.C.S. §  6502(b) (relating to summary offenses). Under 75 Pa.C.S. §  6104(c) (relating to administrative duties of department), the Department of Transportation may make necessary and reasonable investigations to procure information required to enforce this chapter.

   The provisions of this §  173.6 adopted November 5, 1993, effective November 6, 1993, 23 Pa.B. 5309.