Interpretation ID: 23532.ztv

Mr. Daniel Watt
280 Lindo Court
Unit A
Morgan Hill, CA 95037

Dear Mr. Watt:

This is in reply to your email of August 22, 2001, to Michael Cole of this agency.

You related having seen trucks using light emitting diodes (LEDs) instead of incandescent bulbs for their taillamps, and asked whether "red LEDs installed in place of a bulb [in] a clear taillight meet the color 'red' requirements. Or would that be a non-compliance because the housing was not certified for use with LEDs?"

Under Federal law, lighting equipment on motor vehicles must be designed to comply with 49 CFR 571.108 Standard No. 108, Lamps, Reflective Devices, and Associated Equipment. The manufacturer of the vehicle then certifies that the vehicle complies with all applicable Federal motor vehicle safety standards including Standard No. 108. The original rear lamps on the trucks that you saw were equipped with incandescent bulbs.

Paragraph S5.8.1 of Standard No. 108 specifies that "each lamp, reflective device, or item of associated equipment manufactured to replace any lamps, reflective device, or item of associated equipment on any vehicle to which [Standard No. 108] applies shall be designed to conform to this standard." This means that a replacement item must be designed to conform to the standard in the same manner as the vehicle manufacturer certified compliance with the original equipment installed. A rear replacement lamp equipped with LEDs would not be designed to conform to the standard in the same manner as the original equipment, and would therefore not comply with S5.8.1. Whether it is legal to use replacement equipment such as the LEDs on the public roads is not a matter of Federal law but of State law. We are not conversant with state laws and cannot advise you about this. You might want to contact the California Department of Highway Patrol for its views on this subject.

Substituting LEDs into a lamp that was designed to incorporate incandescent light sources raises safety concerns. An incandescent light source emits light when an electric current passes through a resistant metallic wire (filament). The position and shape of the filament, along with other design elements, define the unique electrical and photometric characteristics of the light source. Lamp designers incorporate these characteristics into the original optical design of the lamp. Thus, substitution of the original light source with one of a different design may negatively impact the photometric performance of a lamp below the minimum required for compliance with Standard No. 108. In addition, other functions required by Standard No. 108 may be affected by substitution of an LED, such as operation of the illuminated turn signal pilot indicator (S5.5.6).

Sincerely,

John Womack
Acting Chief Counsel

ref:108
d.2/4/02