ID: 571-108 -- LED headlamps motorcycles -- Stanley Electric Co. -- 11-006845

ID: aiam4443

Dear Mr. Maeda: This is in reply to your letter of June 30, 1987 asking for an interpretation of paragraph S4.1.1.36(b)(3) of Motor Vehicle Safety Standard No. 108. That paragraph specifies in pertinent part that a replaceable bulb headlamp shall be designed to conform to Section 6.1-Aiming Adjustment Test, of SAE Standard J580 AUG79 Sealed Beam Headlamp Assembly. Section 6.1.1 states that 'when the headlamp assembly is tested in the laboratory, a minimum aiming adjustment of +/-4 deg. shall be provided in both the vertical and horizontal planes.' You have asked whether the aiming adjustment is to be achieved by the headlamp assembly, or by both the headlamp assembly 'and by the headlamp when it is mounted on the vehicle.' SAE J580 applies to the design of headlamp assemblies, including the functional parts other than the headlamps, such as aiming and mounting mechanisms and hardware. The assembly may include one or more headlamps. Although the headlamp assembly is tested in the laboratory, its design must be identical to the headlamp assembly used on the vehicle. Thus, if the aiming adjustment requirement is met by the headlamp assembly in the laboratory, it should also be met when the assembly is installed on the vehicle. An individual headlamp installed on the vehicle need not meet the aiming adjustment test unless that headlamp is part of a headlamp assembly comprising only one headlamp. I hope that this answers your question. Sincerely, Erika Z. Jones Chief Counsel;

ID: aiam5357

"Dear Mr. Shetler: This is in reply to your letter of February 7, 1994 to the Associate Administrator for Enforcement requesting an interpretation of Federal Motor Vehicle Safety Standard No. 108. So that we may serve you better in the future, please note that the Office of Chief Counsel is the one to which requests for interpretations should be addressed. You have asked whether the 'proposed application of a projector beam headlamp to a motorcycle' will meet the requirements of Standard No. 108. In this headlamp 'the projector beam (lower beam) is located on the left side and the high beam is on the right side.' You continue by saying that 'the outer lens of the headlamp assembly is symmetrically positioned about the vertical centerline,' and you ask whether the headlamp complies with the requirements of Table IV of Standard No. 108. Table III of Standard No. 108 requires a motorcycle to have at least one headlamp. Table IV requires the headlamp to be located 'on the vertical centerline, except that if two are used they shall be symmetrically disposed about the vertical centerline.' The device you describe contains the upper and lower beams in one housing and hence is a single headlamp. Although your projector beam headlamp would be mounted literally on the vertical centerline, the beams provided by the headlamp are located on either side of the centerline and are therefore asymmetrical in relation to the centerline of the motorcycle when either beam is activated. A redesign of the lamp so that its vertical centerline becomes its horizontal centerline and Line A becomes the vertical centerline would be a configuration that meets Table IV since both beams of the single headlamp would then be located on the vertical centerline. SAE J584 does not specify the location of one beam in relation to the other for dual beam motorcycle headlamps, i.e. whether one beam is to be mounted above or below the other. Your second question concerns an interpretation of S5.1.1.23. This paragraph provides an alternative for motorcycles to the headlamps specified by Table III, and allows a motorcycle to be equipped with 'one half of any headlighting system specified in S7 which provides both a full upper beam and full lower beam, and where more than one lamp must be used, the lamps shall be mounted vertically, with the lower beam as high as practicable.' You have asked whether this means that your proposed headlamp 'shall be mounted on the upper half and the high beam shall be on the lower half when using one half of any headlighting system specified in S7,' or 'is our proposed layout in the attachment acceptable?' As I have explained, your proposed layout in the attachment is not acceptable under Table IV without reorientation. The headlighting systems specified in S7 are those intended for four-wheeled motor vehicles (other than trailers). As we understand it, your proposed headlamp has been developed as a headlamp system for motorcycles and not as half of a headlamp system for vehicles other than motorcycles. Because motorcycle photometrics differ from those for vehicle other than motorcycles, your proposed headlamp could not be half of a system specified in S7 which may be used on motorcycles as an alternative to the headlamps specified by Table III. Sincerely, John Womack Acting Chief Counsel";

ID: aiam4271

Dear Mr. Burman: This is in reply to your letter of January 9, 1987, asking for a interpretation of 49 CFR 571.108 Motor Vehicle Safety Standard No. 108 *Lamps, Reflective Devices, and Associated Equipment*. Your client wishes to import, market, distribute and sell a 'clear, plastic headlamp cover...for all makes of cars manufactured in or imported to the United States.' The stated safety purpose of the headlamp cover is 'to protect the glass headlamps on automobiles from breaking.'; three methods of distribution are contemplated: direct sale by you client, sale through auto parts distribution centers, and sale as optional but uninstalled equipment at the time of the vehicle's original sale (the cover in its wrapping would be in the vehicle trunk). You state that the headlamp cover is not intended to be installed by your client, or its distributors and dealers, but will be accompanied by instructions so that the vehicle owner may install it. Warnings will be provided 'about minimum Federal photometric requirements'. You wish to know whether the headlamp cover is subject to Standard No. 108 or any other Federal regulation and, if so, the effect and impact of such regulation.; A plastic headlamp cover is 'motor vehicle equipment', defined i pertinent part by Section 102(4) of the National Traffic and Motor Vehicle Safety Act (15 USC 1391(4)) as 'any...accessory, or addition to the motor vehicle....' Its importer is a 'manufacturer', defined in pertinent part by Section 102(5) of the Act as 'any person importing...motor vehicle equipment for resale'. As a manufacturer of motor vehicle equipment your client has the responsibility imposed by Section 151 *et seq* of the Act to notify and remedy in the event that either it or this agency determines that a safety related defect exists in the product, or that it fails to comply with all applicable Federal motor vehicle safety standards. You have already noted that headlamp covers are not 'a regulated safety device' under Standard No. 108. A 'defect' under Section 102(11) includes ' any defect in performance, construction, components, or materials'. Under the best of circumstances a plastic cover when new will reduce light output of a headlamp beneath its designer's intent, whether or not the output falls below the floor established by Standard No. 108 as a *minimum* for headlamp performance. In service, a plastic headlamp cover may contain condensation under certain climatic conditions, or grow increasingly opaque through exposure to ultraviolet rays or other atmospheric components, either of which would further affect the design performance of the headlamp. A conclusion could be reached that such a cover contained a safety related defect and that its importer should notify all purchasers and remedy according to the Act.; Safety problems associated with headlamp covers led to thei prohibition when the headlamp is in use, initially under SAE J580 for sealed beam headlamps and later by its incorporation into Standard No. 108, for both sealed beam and replaceable bulb headlamps. The specific prohibition of J580 is why passenger cars are not manufactured with original equipment headlamp covers. Under Section 108(a)(1)(A) of the Act, if a dealer sells a noncomplying motor vehicle, he is in violation of the Act, and may be subject to civil penalties for it. These penalties, under Section 109, range up to $1000 for a single violation, with a cumulative total of $800,000 for a related series of violations. If a dealer at time of sale provides the means through which a new car meeting all Federal safety standards may be rendered noncompliant immediately after its delivery, we would regard that as tantamount to his having sold a noncomplying motor vehicle in violation of the Act.; Although there is no Federal prohibition against a vehicle owne installing and using headlamp covers, there may nonetheless be local laws covering the sale and use of this equipment. We offer no views of your client's potential exposure under common law, in such situations as use of a deteriorated cover, or when used with a substandard replacement headlamp, except to note that photometric 'warnings' may serve no defensive purpose. Photometric values at the individual test points are judged under laboratory conditions. Service facilities do not contain equipment by which on-vehicle compliance of the headlamp can be judged, and the eye is a subjective and unreliable source to discriminate between complying and noncomplying levels of light output.; I hope that this answers your questions. Sincerely, Erika Z. Jones, Chief Counsel

ID: 571.108--NCC-230201-001 LED Headlights_ M. Baker

February 13, 2024

Mr. Mark Baker, B.S.E.E. Soft Lights

9450 SW Gemini Drive PMB 44671

Beaverton, OR 97008

mbaker@softlights.org

Dear Mr. Baker:

This responds to your letter and email dated June 27, 2021 and October 31, 2021, respectively, regarding the legal status and safety of motor vehicle headlamps that use light-emitting diode (LED) technology as the light source. Please note that our answer below is based on our understanding of the specific information provided in your letter and email.

You ask about the “legality of LED headlights.” You state your belief that Federal Motor Vehicle Safety Standard (FMVSS) No. 108 does not regulate “peak luminance, absolute spectral power distribution or flicker” and that the standard “only applies to spherical emitters such as tungsten- filament and gas-discharge and is not applicable to non-uniform luminance flat-source emitters such as LED chips.” You ask whether it is “NHTSA’s position that FMVSS No. 108 is only applicable to uniform luminance emitters which can be regulated by setting maximums for luminous intensity without the need of setting peak luminance maximums” and whether “NHTSA [has] approved the use of spatially heterogeneous visible radiation for use as the light source used in vehicle headlights.” You state your concerns about adverse health impacts due to the performance characteristics of LEDs, such as high peak luminance, high-color temperature, high-energy blue wavelength light, and flicker. You request NHTSA’s opinion about the “sufficiency” of FMVSS No. 108 regarding these health concerns.

We understand you to use “uniform luminance emitters” to refer to filament (halogen/tungsten) and high-intensity discharge (HID) light sources, and “non-uniform” or “heterogenous emitter” to refer to LED light sources. We therefore understand you to be asking whether LEDs are legal as a light source in motor vehicle headlamps under FMVSS No. 108, and, if they are legal, what is NHTSA’s position on the safety of LED light sources in headlamps with respect to “eye safety, mental safety, and visual performance.”

Background

NHTSA is authorized by the National Traffic and Motor Vehicle Safety Act (Safety Act, 49 U.S.C. Chapter 301) to issue FMVSS that set performance requirements for new motor vehicles and new items of motor vehicle equipment. The Safety Act requires manufacturers to self-certify that their vehicles and equipment conform to all applicable FMVSS in effect on the date of manufacture. NHTSA also investigates safety-related defects.

FMVSS No. 108, “Lamps, reflective devices, and associated equipment,” applies to “[p]assenger cars, multipurpose passenger vehicles, trucks, buses, trailers (except pole trailers and trailer converter dollies), and motorcycles” and covers, among other things, “original and replacement lamps, reflective devices, and associated equipment” for motor vehicles. The standard specifies performance requirements for headlamps. The most common types of headlamps are integral beam (S10.14) and replaceable bulb (S10.15, S11) headlamps.

NHTSA has stated that LED light sources are permitted as part of an integral beam headlamp if they are wired in series such that a failure of one LED would cause all the LEDs to cease functioning, and they otherwise comply with all relevant FMVSS.1 Paragraph S4 of FMVSS

No. 108 defines an integral beam headlamp as “a headlamp … comprising an integral and indivisible optical assembly including lens, reflector, and light source, except that a headlamp conforming to paragraph S10.18.8 or paragraph S10.18.9 may have a lens designed to be replaceable.” The standard does not contain performance requirements for a light source that is part of an integral beam headlamp, but instead specifies performance requirements for the complete headlamp. These include (among other things) photometry, through minimum and maximum candela at specified test points,2 color, which must remain within specified boundaries,3 and that the headlamp be steady burning.4

While LED light sources that are part of an integral beam headlamp are permitted as noted above, no LED light source is currently permitted to be used in a replaceable bulb headlamp. FMVSS No. 108 contains specific requirements for the replaceable light sources (i.e., bulbs) used in replaceable bulb headlamps. These requirements are intended to support light source interchangeability. Paragraph S11 of the standard requires that “[e]ach replaceable light source must be designed to conform to the dimensions and electrical specifications furnished with respect to it pursuant to part 564 of this chapter[.]”5 Part 564 requires that replaceable bulb manufacturers submit to NHTSA for review and acceptance various design specifications for the bulb. If accepted, this design information is then placed in a publicly available docket to facilitate the manufacture and use of those light sources. As of the date of this letter, no submission that includes LEDs as the light source for a replaceable bulb headlamp has been listed in the docket. Therefore, no LED replaceable light source may be used in a replaceable bulb headlamp.

Discussion

Pursuant to FMVSS No. 108, paragraphs S4 and S10.14, LEDs are allowed to be used as a light source in integral beam headlamps as long as the headlamp conforms to all applicable headlamp requirements in FMVSS No. 108. However, LEDs are not currently permitted in a replaceable bulb headlamp. Nevertheless, illegal LED headlamp replaceable light sources may be available for purchase on the internet, and although these lights do not conform to the requirements of FMVSS No. 108, some consumers purchase and install these LED light sources in their replaceable bulb headlamps. While NHTSA regulates the manufacture and sale of light sources, it generally does not regulate the modifications individuals make to their own vehicles. It is therefore left to State law to address installation of an LED replaceable light source in a headlamp.

FMVSS No. 108 does not directly regulate what you describe as peak luminance as measured in nits or the spectral power distribution of the headlamp light source. However, this is indirectly regulated through the headlamp performance requirements, such as the photometry and chromaticity requirements. Additionally, flicker is regulated through the requirement that lower beam headlamps be steady burning. We also note that, although FMVSS No. 108 requires that the light emitted by headlamps be white, the permissible boundary of white includes colors that may be perceived by the human eye as white with a yellow tint and white with a blue tint.6

In your communications, you raise concerns about the health impacts of LED headlamps. We are aware of concerns raised about possible adverse effects of certain LED devices, particularly as used in street lighting that emits excess blue light.7 NHTSA’s focus is on automotive safety, but the agency recognizes that separate expertise resides in sister agencies that are health-focused, such as the Food and Drug Administration.

I hope this information is helpful. If you have any further questions, please feel free to contact Eli Wachtel of my staff at this address or at (202) 366-2992.

Sincerely,
 

John Donaldson
Acting Chief Counsel

1 Letter from Stephen Wood, Acting Chief Counsel, NHTSA, to Takayuki Amma, Manager, Koito Manufacturing Co. (Dec. 21, 2005). Letter from O. Kevin Vincent, Chief Counsel, NHTSA, to Junichi Hasegawa, Stanley Electric Co. (Apr. 8, 2013). Interpretation letters are available on NHTSA’s online interpretations database at https://www.nhtsa.gov/nhtsa-interpretation-file-search.

2 Photometry requirements for headlamp systems can be found in FMVSS No. 108, Tables XVIII and XIX.

3 See FMVSS No. 108, Table I-a (headlamp color). Chromaticity requirements are pursuant to FMVSS No. 108 S14.4.

4See FMVSS No. 108 Tables I-(a and c). NHTSA has stated that “steady burning” means “light that is essentially unvarying in intensity.” See Letter from Frank Berndt, Chief Counsel, NHTSA, to United Sidecar Association, Inc. (Feb. 9, 1982). A device may fail to meet this requirement where the driver “would not see a signal that was consistent or reliable in its meaning.” See Letter from Paul Jackson Rice, Chief Counsel, NHTSA, to Bob Abernathy, Idea’s Inc. (Sept. 7, 1990) (applying steady burning in a taillamps context). In the context of a modulating motorcycle headlamp, we have stated that “there is no failure to conform if the modulating light from the lamp is perceived to be a steady beam.” Letter from John Womack, Acting Chief Counsel, NHTSA, to Joe De Sousa (March 10, 1994).

5 See Letter from John Womack, Acting Chief Counsel, NHTSA, to Nancy Tavarez, Beitrix Industries (Aug. 30, 1995) (clarifying application of Part 564 to replaceable headlamp bulbs).

6 Letter from Frank Seales, Jr., Chief Counsel, NHTSA, to Richard Hodson, (July 4, 2000) (stating that “SAE J578c defines white by blue, yellow, green, red, and purple boundaries within a chromaticity diagram. Thus, it is possible to design a headlamp that emits a light that approaches the blue boundary and is perceived as having a blue tint but which nevertheless remains within the boundaries that define "white." These headlamps would comply with the color requirements of Standard No. 108.”).

7 See “AMA adopts guidance to reduce harm from high intensity street lights,” American Medical Association, June 14, 2016, available at https://www.ama-assn.org/press-center/press-releases/ama-adopts-guidance-reduce-harm-high- intensity-street-lights.

ID: aiam5614

"Re: Headlamp System Containing Fog Lamp Dear Mr. Matsui: This replie to your letter of August 11, 1995, with reference to possible headlamp systems that produce a fog lamp beam, as well as upper and lower beams. According to your letter, 'the fog lamp is reciprocally incorporated with the high beam headlamp, using one dual-filament bulb (ex., HB2). The high beam and the fog lamp will not be lit simultaneously.' You refer to paragraph S5.1.3 of Federal Motor Vehicle Safety Standard No. 108 and conclude that 'such a combination will not impair the effectiveness of the headlamp.' We agree, with respect to the headlamp itself, that a fog lamp operating simultaneously with the lower beam will not impair the effectiveness of the lower beam's photometrics and ability to illuminate the roadway. We view this as a supplement to the lower beam. However, under S5.1.3, the question is whether the fog lamp, either operating alone or when the lower beam headlamp is activated, will impair the effectiveness of any front lighting equipment that is required by Standard No. 108. The responsibility for the determination of compliance with S5.1.3 is not Stanley's, but that of the manufacturer of the vehicle in which the combination headlamp is installed, who must certify that its vehicle meets all applicable U.S. Federal motor vehicle safety standards. The other front lighting equipment required by Standard No. 108 consists of parking lamps and turn signal lamps. The amber parking lamps serve to mark a vehicle, a function incidentally served by white fog lamps. Thus we do not believe that the Stanley headlamp would impair the effectiveness of parking lamps in any position in which the headlamp may be installed on the front of a vehicle. The situation differs with respect to turn signal lamps. A vehicle manufacturer must take care to ensure that a vehicle on which the combination headlamp is installed conforms to the requirements of Standard No. 108 and to paragraph 5.1.5.4 of SAE Standards J588 NOV84 or J1395 APR85, the two turn signal standards incorporated by reference in Standard No. 108. Paragraph 5.1.5.4 treats the relationship between luminous intensity and photometrics 'where the front turn signal is mounted in close proximity to the low beam headlamp or any additional lamp used to supplement or used in lieu of the low beam, such as an auxiliary low beam or fog lamp.' It does this by establishing luminous intensity multipliers based upon the distance that separates the lamps. For example, if the space between the front turn signal and the lighted edge of the fog lamp is 75 mm to less than 100 mm, the photometric requirements for a front turn signal lamp are 1.5 times more than those required when the spacing is 100 mm or more (Paragraph S5.3.1.7 of Standard No. 108 requires the multiplier at this distance to be 2.5 when the lamp is a lower beam headlamp rather than a fog lamp). Finally, as a cautionary note, we believe that Stanley should evaluate the glare potential of the headlamp when the fog lamp and lower beam are operating simultaneously, as it is important to safety that oncoming drivers not be distracted or discomforted in the operation of their vehicles. If you have any further questions, you may refer them to Taylor Vinson of this Office (phone: 202-366-5263). Sincerely, John Womack Acting Chief Counsel";

ID: aiam4717

"Dear Mr. Rogers: This is in reply to your letter asking fo confirmation that an interpretation of a notice of proposed rulemaking remains in effect with respect to the final rule based upon that proposal. I regret the delay in responding. Specifically, you reference an interpretation dated September 12, l988, that this Office provided Koito Corporation, informing it that each of the two Vehicle Headlamp Aiming Device (VHAD) designs depicted 'complies with the intent of S7.7.5.2' of Standard No. l08. The second design consisted of a detachable spirit level that would be inserted in the bulb socket for the purpose of aiming the headlamp. We informed Koito that 'under subsection (b)(7) photometric testing is provided for 'the VHAD and headlamp assembly (if the headlamp is separable or intended to be used with the VHAD)', and that this meant that the VHAD may be integral with the headlamp assembly or separate from it. However, we also cautioned that our comments were based upon the proposal, and could change with the issuance of the final rule. You have commented that the final rule was the same with respect to the pertinent VHAD wording. This is not entirely true. The final rule (paragraph S7.7.5.2(b)(vii)) omitted the parenthetical phrase '(if the headlamp is separable or intended to be used with the VHAD)'. You also noted that paragraph S7.7.5.2(c)(l) of the final rule defines a headlamp assembly as '(the headlamp(s) and the integral or separate VHAD mechanism)'. The intent of this language is to specify a VHAD that is a permanent part of the headlamp, and hence integral, or to have a separate VHAD that is part of the mounting mechanism. It was not meant as permitting a VHAD that could be physically separated from headlamp or the mounting mechanism. Thus, in our view and upon our further consideration of the matter, a detachable VHAD does not meet the 'intent' of the final rule. This means that the spirit level design described in your letter, which is not integral to the headlamp or mounting mechanism, is not permissible. We shall provide Koito with a copy of this letter. Sincerely, Stephen P. Wood Acting Chief Counsel";

ID: aiam4617

"Dear Mr. Grandy: This is in reply to your recent letter to th Administrator Designate, Jerry Curry, on behalf of your constituent Daniel Weichmann, Jr., of Hampton. You enclosed a copy of Mr. Weichmann's letter to this agency with respect to headlamp covers which, regrettably, we have been remiss in answering. You asked that we review this matter and that you be provided a copy of our response. We are pleased to reply directly to you, with a copy to Mr. Weichmann so that he may be apprised immediately of our views. Mr. Weichmann was advised by the Iowa Department of Transportation on October 10, 1988, that 'The department specifically does not approve head lamp covers', because Iowa has adopted 'Federal standards on equipment approval'. Consequently, 'If the headlamp covers in question meet the Federal Standards they would qualify under Iowa law.' Thus, Mr. Weichmann asked us whether headlamp covers are approved by this agency. Headlamp covers are not permissible as items of original motor vehicle equipment. Paragraph S7.7.5 of Federal Motor Vehicle Safety Standard No. l08 Lamps, Reflective Devices, and Associated Equipment, in pertinent part, states that when headlamps are operated they 'shall not have any styling ornament or other feature, such as a translucent cover or grill, in front of the lens.' Although Standard No. l08 was only recently amended to state this prohibition expressly (I enclose a copy of the amended standard), the prohibition has existed since January l968 through the incorporation by reference in Standard No. l08 of an SAE headlamp Standard, J580b, which contained the identical language. The safety reason for the prohibition is the reduced effectiveness of a headlamp beam when it must pass through an extra layer of glazing, particularly if that glazing is tinted, yellowed, or cracked, or if moisture has condensed on the inside of the cover. Thus, headlamp covers are also implicitly prohibited by paragraph S5.1.3 of Standard No. l08 which forbids the installation of optional original equipment that impairs the effectiveness of lighting equipment, such as headlamps, that are required by Standard No. l08. The Iowa DOT's views are consistent with the provisions of the National Traffic and Motor Vehicle Safety Act which permit States to enact State motor vehicle safety standards applicable to new vehicles provided that they are identical to Federal ones covering the same aspect of performance. Although the Federal standards do not regulate operation of a vehicle after it is sold, and hence could not prohibit a vehicle owner in Iowa from installing headlamp covers and operating his vehicle with them, Iowa's enforcement of a headlamp cover prohibition for vehicles in use would be consistent with its prohibition of them as original vehicle equipment. However, we cannot interpret Iowa law, and reach no conclusion as to whether its statutes or regulations have that effect. Should either you or Mr. Weichmann have further questions, we shall be pleased to answer them. Sincerely, Jeffrey R. Miller Acting Administrator Enclosure cc: Daniel Weichmann, Jr. The Honorable Fred Grandy Mason City IA /";

ID: aiam2897

Dear Mr. Eguchi: This is in reply to your letter of September 22, 1978, to Bill Eason o our Office of Rulemaking asking several questions about motor vehicle headlamps and the amendment to Motor Vehicle Safety Standard No. 108 issued on July 27, 1978.; Your questions and our answers are: 1. Ichikoh headlamps are designed to comply with SAE Standard J579 with maximum candela not exceeding 37,500. Does the amendment allow Ichikoh to place 'DOT' and the new designation code on the lens of each headlight?; Ichikoh's practice reflects compliance with the option afforded b S4.1.1.33 until July 27, 1978. The deletion of candlepower permitted by J579c but does not require it. Thus, Ichikoh may continue its existing practice under the amendment. One purpose of the marking code, however, is to enable a consumer to replace original equipment headlamps with lamps of compatible photometric output. Currently, S4.1.1.21 as amended requires the lens of each Ichikoh headlamp designed to conform to J579c to be marked with the new code on and after July 1, 1979. Obviously such a marking will be misleading if, even though designed to conform to J579c, a headlamp's maximum candela does not exceed 37,500. Accordingly, we are reviewing this problem with the idea of proposing rulemaking that would delete the code requirement for all headlamps whose maximum candela does not exceed 37,500. We do not anticipate a change in the requirement of S4.1.1.21 that the lens of each J579c headlamp be marked with the 'DOT' symbol since Ichikoh headlamps comply with J579c, even if they do not take advantage of the now-permissible maximum.; 2. With reference to your quality control system, will the headlamp 'be allowed to exceed 37,500 cd without any modification of the light source (filament) and wattage?'; I am not quite sure what you mean. If you are asking whether Ichiko may relax quality control so that an occasional headlamp may exceed 37,500 cd, the answer is yes. Headlamps designed to J579c are not restricted to the maximum imposed by J579a.; 3. You ask our comments on possible mismatch of headlamps on the sam vehicle, i.e., one low intensity headlamp and one high intensity headlamp.; NHTSA is concerned about this possibility and, as indicated in reply t your first question, is considering rulemaking to delete the code requirement for low intensity J579c headlamps. Your second question, however, does raise the issue of identification of headlamps whose candela may exceed 37,500 but whose maxima are far less than 75,000. We shall also consider this issue and may issue a consumer bulletin advocating replacement of headlamps in pairs to help resolve this potential problem.; 4. You ask whether NHTSA intends to adopt the concept of ECE Regulatio No. 20 in the near future. This Regulation requires a mark on a headlamp lens indicating candlepower grade.; The NHTSA does not plan to adopt the requirements of Regulation No. 2 because this regulation is in essence an indicator of quality control.; I hope this answers your questions. Sincerely, Joseph J. Levin, Jr., Chief Counsel

ID: aiam4993

Dear Mr. Aihara: This responds to your letter of March 16, 1992 requesting an interpretation of the applicability of the moisture prohibition of S7.4(i)(6) of Federal Motor Vehicle Safety Standard No. 108. Initially, we would like to call your attention to the fact that S7.4(i)(6), which you quoted in its entirety, was amended on March 11, 1991, to delete the requirement that a headlamp meet the photometric requirements after a humidity test. S7.4(i)(6) now states in pertinent part that, after a humidity test conducted in accordance with S8.7, 'the inside of the headlamp shall show no evidence of delamination or moisture, fogging or condensation visible without magnification.' You have attached a drawing of a vented headlamp with an onboard aiming system. The headlamp is available with two different types of bubble indicators. Your first question is: 'After the humidity test, both types . . . show the fogging in the location as shown in attached sketches. But, this fogging is gone at normal temperature. * * * Is such fogging acceptable after the humidity test?' Your second question is whether ''the inside of the housing' means the lens and reflector portions' or 'the entire inside portion of headlamps?' The humidity test was adopted for replaceable bulb headlamps in l983. Allowing humidity or water in headlamps causes slow degradation of the reflector over the long term. The presence of humidity results in spots on the reflector and lens, and eventual photometric failure. The humidity test is designed to assure that the vents in vented headlamps eliminate moisture in the headlamp when exposed to air flow with the headlamps off, thus assuring adequate performance in long term use. The provision for onboard headlamp aiming devices was not adopted until 1989, and, with respect to replaceable bulb headlamps, did not specify that they be located within the headlamp. From the foregoing, it is evident that the humidity test for replaceable bulb headlamps was not adopted to address a problem inherent in the exposure of onboard aiming devices to moisture. These devices were not in use at the time the humidity test was added to Standard No. 108, and they do not contribute directly to the photometric performance of the headlamp. From the diagram you enclosed, the aiming device appears located behind the reflector. It is not possible to determine from your letter whether moisture forms on the exterior or the interior of the aiming device. Although S7.4(i)(6) prohibits moisture 'inside the headlamp' and the aiming device is located inside the headlamp, we would not read the prohibition as extending to the aiming device if the moisture occurs inside that device. Even if the moisture occurs on the exterior of the aiming device, it does not affect the photometric properties of the headlamp. The agency does not wish to impose inadvertent design restrictions that are not directed towards safety, and therefore regards any moisture that may occur on the exterior of the aiming device as outside the prohibition of S7.4(i)(6). This interpretation, however, is limited to the specific design that you have presented. Sincerely, Paul Jackson Rice Chief Counsel;