NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
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NHTSA's Interpretation Files Search
| Interpretations | Date |
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ID: 14387.ztvOpen Mr. Tadashi Suzuki Dear Mr. Suzuki: This responds to your letter of March 14,1997, asking for an interpretation of paragraphs 7.5(d)(1) and (e)(1) of Federal Motor Vehicle Safety Standard No. 108. Pargraph S7.5(d)(1) applies to headlamps equipped with dual filament replaceable light sources and requires that "Headlamps designed to conform to the external aiming requirements of S7.8.5.1 shall have no mechanism that allows adjustment of an individual light source, or, if there are two light sources, independent adjustments of each reflector." Paragraph S7.5(e)(1) applies to a headlamp system equipped with any combination of replaceable light sources except those specified in S7.5(d), and requires that "Headlamps designed to conform to the external aim requirements of S7.8.5.1 shall have no mechanism that allows adjustment of an individual light source, or, if there are two replaceable light sources, independent adjustments of each reflector." You have enclosed a sketch of two headlamp designs, called "Example 1" and "Example 2." You believe that "Example 1" can meet both requirements and that "Example 2" cannot due to the independent adjustment of the two reflectors. You ask whether or not your interpretation is correct. "Example 1" depicts a headlamp with two light sources (Type HB3 and Type HB4), and "Reflector" (Upper Beam & Lower Beam)" joined at the center, and a vehicle headlamp aiming device (VHAD) identified as "VHAD (Upper Beam & Lower Beam)". As noted above, S7.5(d)(1) applies to headlamps with dual filament replaceable light sources. Type HB3 and Type HB4 are single filament replaceable light sources. Therefore, S7.5(d)(1) does not apply to your "Example 1" headlamp design. Additionally, because "Example 1" has a VHAD, paragraph S7.5(d)(1) does not apply, being intended for externally-aimed headlamps. For the same reason, it does not need to comply with S7.5(e)(1). "Example 2" depicts a headlamp with two light sources (Type HB3 and Type HB4), and with two separate reflectors. One light source is identified as "Upper Beam" and the other as "Lower Beam." Each light source has its own VHAD. As with "Example 1", paragraph S7.5(d)(1) does not apply to this headlamp design because it incorporates single filament light sources. Also, as with "Example 1", paragraph S7.5(e)(1) does not apply. In summary, neither S7.5(d)(1) nor S7.5(e)(1) apply to the examples. Because both Examples appear to be equipped with "on-vehicle aiming" (see paragraph S7.8.5.2), either Example would appear to comply with the relevant provisions of S7.5(e). If you have further questions on this letter, you may FAX Taylor Vinson of this Office (202-366-3820). Sincerely, John Womack Acting Chief Counsel ref:108 d:4/25/97 |
1997 |
ID: 86-1.27OpenTYPE: INTERPRETATION-NHTSA DATE: 02/10/86 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: M. Iwase -- Manager, Technical Administration Dept., Koito Mfg. Co. Ltd. TITLE: FMVSS INTERPRETATION TEXT: Mr. M. Iwase Manager, Technical Administration Dept. Koito Mfg. Co. Ltd. Shizuoka Works 500 Kitawaki Shimizu-shi, Shizuoka-ken JAPAN
This is in reply to your letter of August 30, 1985, to Jere Medlin, Office of Rulemaking, asking for an interpretation of the recent amendment to Motor Vehicle Safety Standard No. 108 allowing motorcycles to be equipped with modulating headlamp systems. In your first question, you asked for confirmation of your understanding of the modulation cycle and maximum power. We confirm that your interpretation is correct. Please note that the value of A on the modulation cycle of your diagram may be equal to or less than the value of D. However, the requirement relates to C/D rather than C/A, and it is the value of C/D that must be at least 0.17. With reference to the electrical wiring diagram that you provided, you have asked whether the voltage drop maximum of 0.45 volt in S4.6.1(g) applies to condition (a) (when the modulator switch is "on") or condition (b) (when the modulator switch is "off"). The maximum voltage drop applies to both conditions (a) and (b), i.e., when the modulator is operating and when the headlamp is on. Paragraph S4.6.1(g) states "When tested in accordance with the test profile shown in Figure 9, the voltage drop across the modulator when the lamp is on at all test conditions ....shall not be greater than .45 volt." This not only includes the period of time when the modulator is operating, but also the period when the headlamp is on without the modulator. Paragraph S4.6.1(e) requires that both the upper and lower beams remain operable in the event of a modulator failure, and thus the agency views headlamp operation without modulator as one of the test conditions included in the term "test conditions" in S4.6.1(g). We would like to comment further that when the modulator is turned on, during the test profile of Figure 9, it should be activated when the headlamp is on, since most manufacturers of motorcycles wire their vehicles so that the headlamp is on when the ignition switch is on.
Your next question concerns the acceptability of three types of modulator switch systems which you have diagrammed. All your designs appear consistent with the requirements of Standard No. 108. The modulator must be capable of being switched out of the circuit if it fails, in which case upper and lower beams could be used im a steady-burning mode. This does not necessarily mean another switch, other than the Hi-low beam switch, however.
In response to your final question, you may write Herbert Thrower, Jr., President, Dotech Inc., P.O. Box 3322, Charlotte, N.C. 28210. Sincerely,
Erika Z. Jones Chief Counsel
SUBJECT: ACTION: Request for Interpretation of Motorcycle Modulating Headlamp Requirements (FMVSS No. 108) by Koito
FROM: Barry Felrice Associate Administrator for Rulemaking
TO: Jeffrey Miller Chief Counsel
Rulemaking received the attached request for an engineering interpretation of the intent of certain requirements for motorcycle headlamp modulators.
Herein is the engineering interpretation of the requirements in question. Please prepare the official response to Koito based on this information.
In response to question 1:
1. Yes, 0.21 y 0.30 sec., as suggested by koito, is correct. 2. Yes, x/y = 50 to 70%, as suggested by Koito, is correct. 3. The value of A may be equal to or less than the value of D. However, the requirement relates to C/D rather than C/A. It is the value of C/O that must be at least 0.17.
In response to question 2:
The intent of the requirement in S4.6.1 is to assure that less than 0.45 volts is lost as a result of the addition to a headlamp circuit for the purpose of modulating the headlamp. The 0.45 volts is for night operation condition of the headlamp (i.e. condition "b" in Koito's letter). In response to question 3.
We do not approve designs, but offer the following comments on the intent of the rule. The modulator should be capable of being switched out of the circuit if it fails, in which case upper and lower beams could be used in a steady burning mode. This does not necessarily mean another switch, other than the Hi-low beam switch, however. All your designs appear to be consistent with the requirements of the standard, however some appear more desirable, based on number of switches, case of use, etc., than others. In response to your request for the address of Dotech, a modulator manufacturer, the following information is furnished: Mr. Herbert Thrower, Jr.. President Dotech Inc. P.O. Box 3322 306 Clanton Road Charlotte, N.C. 28210 Tel. No. (704) 523-6727
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ID: Shih.3OpenMr. Simon S. Shih Dear Mr. Shih: This responds to your e-mail, in which you seek clarification regarding the legality of high intensity discharge (HID) headlamp conversion sets, specifically whether it is legal to manufacture or sell sets of HID headlamps to replace original equipment halogen headlamp sets. We are pleased to have the opportunity to answer your questions related to Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, Reflective Devices and Associated Equipment. By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue FMVSSs that set performance requirements for new motor vehicles and items of motor vehicle equipment. As a preliminary matter, we would clarify that we have no authority either to approve or disapprove motor vehicles or items of motor vehicle equipment. We do advise correspondents of the relationship of their products to applicable FMVSSs and other regulations that we administer. If a product is covered by one or more of our safety standards, its manufacturer must certify compliance of the product with all applicable FMVSSs prior to its importation or offering such product for sale. The symbol "DOT" on replacement lighting equipment is often mistaken for "DOT approval" of the equipment, but, in fact, it reflects the manufacturers own certification of compliance. We believe that your questions are addressed by our March 13, 2003, letter of interpretation to Mr. Galen Chen (see enclosure). In that letter, we interpreted FMVSS No. 108 as requiring headlamps manufactured to replace original equipment headlamps to comply with all applicable photometry requirements using the replaceable light sources intended for use in the headlighting system on the vehicle for which the replacement headlamp is intended. Unlike other lamps, FMVSS No. 108 specifically regulates headlighting systems, including their light sources (see S7.1, S7.5, and S7.7). We adhered to this interpretation in a recent interpretation to Calcoast-ITL (69 FR 60464 (Oct. 8, 2004))(see enclosure). Because replaceable light sources are, by regulation, designed to be non-interchangeable, it would not be possible for an HID headlamp conversion set to meet the standards photometry requirements for an original equipment headlamp system using a halogen light source, so the replacement lamps could not be sold for this purpose. Furthermore, a headlamp dealer or motor vehicle repair business could not remove the original halogen headlamps and install HID replacement headlamps without violating 49 U.S.C. 30122. That section prohibits manufacturers, distributors, dealers, and motor vehicle repair businesses from making inoperative equipment installed in accordance with a Federal motor vehicle safety standard. We cannot comment on the specific replacement lighting products that you mentioned because we do not have sufficient information on them. Finally, in a subsequent e-mail, you asked whether our regulations require HID lighting systems to include "auto-leveling" and washing systems, similar to those incorporated in vehicles sold in Europe. The answer is no. FMVSS No. 108 does specify aimability performance requirements under paragraph S7.8 of the standard, but that paragraph does not require an "auto-leveling" capability. The standard also does not contain any requirement for a headlamp washing system. s it may be of interest to you, we also have enclosed a copy of our November 18, 2002, letter of interpretation to Mr. Jeff Deetz, which relates to kits that substitute the type of light source in existing headlamps. I hope you find this information useful. If you have further questions, please feel free to contact Eric Stas of my staff at this address or by telephone at (202) 366-2992. Sincerely, Jacqueline Glassman nclosures |
2004 |
ID: 1984-3.33OpenTYPE: INTERPRETATION-NHTSA DATE: 10/29/84 FROM: FRED W. BOWDITCH -- MVMA TECHNICAL AFFAIRS DIVISION TO: DIANE K. STEED -- ADMINISTRATOR NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 03/14/85 EST, FROM BARRY FELRICE TO FRED W. BOWDITCH, REDBOOK A27, STANDARD 108 TEXT: Dear Miss Steed: The Motor Vehicle Manufacturers Association of the United States, Inc. (MVMA) * files this petition under 49 CFR Part 552 requesting amendment of Federal Motor Vehicle Safety Standard No. 108. * MVMA members are AM General Corporation, American Motors Corporation, Chrysler Corporation, Ford Motor Company, General Motors Corporation, International Harvester Company, M.A.N. Truck and Bus Corporation, PACCAR Inc., Volkswagen of America, Inc. and Volvo North America Corporation. MVMA requests removal from section 4.1.1.36(a)(2) of the limitation requiring the three aiming pads to be located on the exterior face of the headlamp lens. So long as the aiming pads are accessible to the adjustable legs of the aimer locating plates described in Figure 9, there is no motor vehicle safety need to limit pad placement to the face of the lens. Adoption of this requested amendment would remove an unwarranted design restriction. By allowing the aiming pads to be located on a part of the headlamp other than the lens, e.g., the mounting flange at the lens-reflector joint, such amendment would facilitate, for example, the design of lower profile replaceable bulb headlamps. Use of such headlamps could enhance the aerodynamic properties of future vehicle designs. Accordingly, we request substitution of the following text for the current section 4.1.1.36(a)(2): "S4.1.1.36(a)(2) Each replaceable bulb headlamp shall have three pads on the front surface of the lamp which form an aiming plane for mechanically adjusting and inspecting headlamp aim. In the front view of the lamp taken in a plane perpendicular to the longitudinal axis of the vehicle, the three pads shall be positioned to match corresponding locations, for either Group I or Group II, that are specified in Figure 9 (front view) for the adjustable legs of the locating plate. The pads shall be designed to permit use of a mechanical aimer conforming to SAE Standard J602 October 1980 "Headlamp Aiming Device for Mechanically Aimable Sealed Beam Headlamp Units", together with an adjustable locating plate described in Figure 9, to check the aim of the Headlamp. Group I aiming pad locations are those prescribed for the 2B1 sealed beam headlamp unit and Group II aiming pad locations are those prescribed for 1A1/2A1 sealed beam headlamp units. Each lens face shall have molded into it the settings, appropriate for that headlamp, of the lengths of the three legs of the adjustable locating plate. Each setting is to be located adjacent to the aiming pad to which it applies. The molded characters specifying the settings shall have a minimum height of 4mm". If you would like to discuss this petition further, please call on us. Very truly yours, |
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ID: nht92-7.12OpenDATE: May 6, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Shigeyoshi Aihara -- Manager, Information Services, Ichikoh America, Inc. TITLE: None ATTACHMT: Attached to letter dated 3/16/92 from Shigeyoshi Aihara to Paul J. Rice (OCC 7113) TEXT: This responds to your letter of March 16, 1992, requesting an interpretation of the applicability of the fogging 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 temperature 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 in 1983. 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 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. |
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ID: aiam3890OpenConfidential; Confidential; Dear Mr. Confidential: This is in reply to your letter of August 30, 1984, (not received unti October 17, 1984) with respect to questions of compliance of lighting and bumper requirements on a vehicle equipped with a variable height control system.; Standard No. 108 requires that the center of a headlamp lens be no less than 22 inches from the road surface. You stated that this minimum might not be met with respect to certain headlamp configurations when the ignition is off, and the hydraulic pressure in the height control system relaxes, a period of approximately three hours. You believe that compliance with the mounting height requirement should be judged 'with the ignition switch in only the 'on' position,' the apparent point at which the height control system begins to operate.; We believe that the minimum height requirement should be met for an lamp at any time in which it is operated for its intended purpose. Since vehicles at rest do not require use of headlamps, the minimum height would be measured at the point after the ignition is on and when the car begins to travel (your letter implies that the time lag between turning on the ignition and restoration of a complying mounting height is a matter of seconds). On the other hand, the hazard warning signal lamps are frequently operated when the vehicle is stopped, and therefore the minimum mounting height of turn signal lamps, through which they operate, must be met with the ignition off, even if the system requires three hours to deplete itself and lower the vehicle to its minimum height.; We also call to your attention paragraph S4.1.3 which forbids th installation of motor vehicle equipment which impairs the effectiveness of lighting equipment required by the standard, and ask that you consider whether a height control system would change vehicle height, pitch, roll, etc., in response to some external or internal condition, in a manner which would affect the performance of headlamps and other lighting equipment.; You have also asked, in essence, which conditions of operation of th system are appropriate for the pendulum and barrier impact tests of the bumper standard, 49 CFR Part 581. Under Sec. 581.5(c), the suspension system is to remain in adjustment and operate in the normal manner, under Sec. 581.6(c) the engine is operating at idling speed. In our opinion, the vehicle is required to meet the pendulum test of Part 581 in any vehicle use scenario in which the system operates, and the barrier test of Part 581 when the engine is idling.; Finally, you requested confidentiality for all information submitte which pertains to the variable height control system. After carefully reviewing the documents, I have determined that your request should be granted. The release of these documents could cause substantial injury to the competitive position of your company. Therefore, I am withholding from the public your letter which contains a detailed description of the variable height control system currently under consideration. I am also deleting all references to the company name. I will instruct all agency personnel having access to this information to accord it confidential treatment.; I hope that this answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: 07-003545asOpenMr. Kiminori Hyodo Deputy General Manager, Regulation & Certification Koito Manufacturing Co., Ltd. 4-8-3, Takanawa Minato-Ku Tokyo Japan Dear Mr. Hyodo: This responds to your letter, in which you ask about the relative location of the lower and upper beam light sources under Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, Reflective Devices, and Associated Equipment. Specifically, you ask if the optical axis, as defined by the manufacturer, can be used to determine the relative location of the lower beam light source to that of the upper beam headlamp. As discussed below, our answer is yes. It is our opinion that for purposes of visual/optically aimed headlamps, the point where the optical axis intersects the lens of the headlamp (as determined by the manufacturer) is the reference point used for purposes of determining the relative location of the beams. By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue FMVSSs that set performance requirements for new motor vehicles and items of motor vehicle equipment (see 49 U.S.C. Chapter 301). NHTSA does not provide approvals of motor vehicles or motor vehicle equipment. Instead, manufacturers are required to self-certify that their products conform to all applicable safety standards that are in effect on the date of manufacture. NHTSA selects a sampling of new vehicles and equipment each year to determine their compliance with applicable FMVSSs. If our testing or examination reveals an apparent noncompliance, we may require the manufacturer to remedy the noncompliance, and may initiate an enforcement proceeding if necessary to ensure that the manufacturer takes appropriate action. The relative locations of lower and upper beam headlamps is governed under paragraphs S7.4(b) and S7.5(d)(2) of FMVSS No. 108. These paragraphs read, respectively: S7.4 * * * (b) The lower and upper beams shall be provided only as follows where each headlamp contains two light sources: (1) The lower beam shall be provided either by the most outboard light source (or the uppermost if arranged vertically), or by all light sources. (2) The upper beam shall be provided either by the most inboard light source (or the lowermost if arranged vertically), or by all light sources. * * * * S7.5(d) For a headlamp equipped with dual filament replaceable light sources, the following requirements apply: * * * * (2) The lower and upper beams of a headlamp system consisting of two lamps, each containing either one or two replaceable light sources, shall be provided as follows: (i) The lower beam shall be provided in one of the following ways: (A) By the outboard light source (or upper one if arranged vertically) designed to conform to: (1) The lower beam requirements of Figure 27-1 or Figure 27-2, or Figure 17-1 or Figure 17-2, if the light sources in the headlamp system are any combination of dual filament replaceable light sources other than Type HB2; or (2) The lower beam requirements of Figure 17-1 or Figure 17-2, if the light sources are Type HB2, or any dual filament replaceable light sources that include Type HB2; or (B) By both light sources in the headlamp, designed to conform to the lower beam requirements specified above. (ii) The upper beam shall be provided in one of the following ways: (A) By the inboard light source (or the lower one if arranged vertically) designed to conform to: (1) The upper beam requirements of Figure 27-1 or Figure 27-2, or Figure 17-1 or Figure 17-2, if the light sources in the headlamp system are any combination of dual filament replaceable light sources other than Type HB2; or (2) The upper beam requirements of Figure 17-1 or Figure 17-2, if the light sources are Type HB2, or any dual filament replaceable light sources that include Type HB2; or (B) By both light sources in the headlamp, designed to conform to the upper beam requirements specified above. We note that the specifications described in paragraphs S7.4(b) and S7.5(d)(2) were originally adopted in the 1970s to apply to four-lamp sealed beam headlighting systems in which each lamp was identical in size and contained only a single light source. When the lamps were mounted horizontally, side by side with identical horizontal centerlines, the outboard lamps were required to be the ones providing the lower beam, which also served to mark the width of the vehicle. When the lamps were mounted vertically, one atop the other with identical vertical centerlines, the lower beam continued to mark the width of the vehicle, but it was required to be the uppermost headlamp in order to provide a greater seeing distance. This established the location priority for the lower beam, that it be the outermost beam, and uppermost beam if the vertical axes of the lamps coincided. As you are aware, in our previous letter of interpretation to you, we stated that manufacturers could use their discretion when specifying the location of the optical axis. We noted that for visual/optically aimed headlamps, the term optical axis as used in FMVSS No. 108 refers to the reference axis (a.k.a. mechanical axis) of the headlamp.[1] We said that because we believe, given the asymmetric nature of modern headlighting systems, the output of a lamp comprised of multiple sources is not in a pre-defined position (such as at the geometric center of the lens), as it is with symmetrical lamps such as turn signals. In these cases, the manufacturer is the entity best positioned to locate the reference axis from which photometric output of the the beam will be measured. NHTSA stated that it will use that reference axis when doing its own testing. For similar reasons, with these kinds of lamps, we believe that the same reference axis (i.e., the optical axis) that is used to align the beam when measuring the photometric output of the lamp is also useful for determining the reference point for the physical location of the lens. As stated above, the purpose of the specifications at issue is to establish the location priority of the lower beam. The optical axis, as defined by the manufacturer, is already used to determine the optical center of the light beam produced. Therefore, as long as the reference axis of the lower beam headlamp is located farther outboard than the reference axis of the upper beam (or uppermost if arranged vertically), such alignment would be permissible under Standard No. 108. If you have any further questions, please contact Ari Scott of my staff at (202) 366-2992. Sincerely yours, Anthony M. Cooke Chief Counsel ref:108 d.11/21/07 |
2007 |
ID: aiam3139OpenMr. M. S. Keshav, Manager - Research & Development, Bajaj Auto Limited, Bombay Poona Road, Akurdi - Poona - 411 035, India; Mr. M. S. Keshav Manager - Research & Development Bajaj Auto Limited Bombay Poona Road Akurdi - Poona - 411 035 India; Dear Mr. Keshav: This is in reply to your letter of September 2, 1979, to Franci Armstrong asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108. SAE Standard J588e August 1970 is the referenced standard for turn signal lamps. Paragraph 4.2 of J588e requires that as mounted on the vehicle 'The optical axis (filament center) of the front turn signal lamp shall be at least 4 inches from the inside diameter of the retaining ring of the headlamp unit providing the lower beam'. You mentioned that on some motorcycles sold in the United States this requirement is satisfied only with the handlebar in the straight ahead position but not when turned to the full lock position. You asked whether this complies with Standard No. 108.; Table IV specifies that the minimum edge to edge separation between th headlamp and turn signal lamp on motorcycles is 4 inches. Most manufacturers have interpreted this requirement to mean that the separation is permanent, and have supplied turn signals that are mounted stationary with the headlamp, and that turn with it so that the separation distance is maintained. Therefore, the configuration you describe would not comply with Standard No. 108 because Federal requirements for location and mounting of lighting equipment are intended to apply to a vehicle under all its operating conditions.; Sincerely, Frank Berndt, Chief Counsel |
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ID: 19699.ztvOpenMr. Tadashi Suzuki Re: Motorcycle Headlamp Arrangement Dear Mr. Suzuki: This is in reply to your letter of March 10, 1999, pointing out an inconsistency between our letter to you of February 22, 1999, and preamble language to a 1996 amendment of Federal Motor Vehicle Safety Standard No. 108. The issue is the measurement of photometrics in two-lamp motorcycle headlamp systems: whether the photometric performance of Figure 32 is applied to each headlamp, or to the combined output of both headlamps. Our first interpretation on this subject was provided to M. Iwase of Koito Manufacturing Co., who asked us about the measurement of photometrics in a two-lamp motorcycle headlamp system. We informed Mr. Iwase on November 29, 1985, that:
We confirmed this interpretation in the preamble of the 1996 amendment to Standard No. 108 adopting a new photometric standard for motorcycle headlamps (61 FR 45359). There we said that:
However, our letter of February 22 informed you that "a [motorcycle headlamp] system of the type described in subparagraph (b) of S7.9.6.2 [a two-lamp system] is not intended to have twice the light output of systems described in S7.9.6.2(a) or S7.9.6.2(c)," which you interpret as contrary to our previous interpretations. You ask that we seek public comment if it is our intent to adopt "one photometric performance for each motorcycle." We appreciate your calling this matter to our attention. We agree that our interpretation is incorrect and withdraw that portion of our letter of February 22 that is inconsistent with prior interpretations. A conflict appears to arise in the context of a motorcycle headlamp system permitted by S7.9.6.2(b), a two-lamp system in which each lamp contains an upper beam light source, or each lamp contains a lower beam light source. This system could produce total beam photometrics of twice the light output of a single beam system (S7.9.6.2(a)or S7.9.6.2(c)). The edges of luminous lens areas of headlamps meeting S7.9.6.2(b) must be no more than 8 inches apart when they are mounted horizontally, and our remarks in our letter of February 22 reflected our concern that this may be an insufficient distance to prevent glare arising from two beams, especially from the lower beam when other drivers are in close proximity. If you intend to produce a two-headlamp system with two full-intensity upper or lower beams, please keep in mind our safety concerns about glare. We intend to study this question in the coming months as part of a petition from the Japanese Automotive Parts Industry Association, and would appreciate any data you may have on this subject. Sincerely, |
1999 |
ID: 19843.ztvOpenMr. Masao Muraoka Re: Motorcycle Headlamp Photometry Dear Mr. Muraoka: This is in reply to your letter of April 6, 1999, pointing out an inconsistency between our letter to Stanley Electric Co. of February 22, 1999, and preamble language to a 1996 amendment of Federal Motor Vehicle Safety Standard No. 108. The issue is the measurement of photometrics in two-lamp motorcycle headlamp systems: whether the photometric performance of Figure 32 is applied to each headlamp, or to the combined maxima of both headlamps. Our first interpretation on this subject was provided to M. Iwase of your company, who asked us about the measurement of photometrics in a two-lamp motorcycle headlamp system. We informed Mr. Iwase on November 29, 1985, that:
We confirmed this interpretation in the preamble of the 1996 amendment to Standard No. 108 adopting a new photometric standard for motorcycle headlamps (61 FR 45359). There we said that:
However, our letter of February 22 informed Stanley Electric that "a [motorcycle headlamp] system of the type described in subparagraph (b) of S7.9.6.2 [a two-lamp system] is not intended to have twice the light output of systems described in S7.9.6.2(a) or S7.9.6.2(c)," which you interpret as contrary to our previous interpretations. You ask that we seek public comment if it is our intent to adopt "one photometric performance for each motorcycle." We appreciate your calling this matter to our attention. We agree that our interpretation is incorrect and withdraw that portion of our letter of February 22 that is inconsistent with prior interpretations. A conflict appears to arise in the context of a motorcycle headlamp system permitted by S7.9.6.2(b), a two-lamp system in which each lamp contains an upper beam light source, or each lamp contains a lower beam light source. This system could produce total beam photometrics of twice the light output of a single beam system (S7.9.6.2(a)or S7.9.6.2(c)). The edges of luminous lens areas of headlamps meeting S7.9.6.2(b) must be no more than 8 inches apart when they are mounted horizontally, and our remarks in our letter of February 22 reflected our concern that this may be an insufficient distance to prevent glare arising from two beams, especially from the lower beam when other drivers are in close proximity. If you intend to produce a two-headlamp system with two full-intensity upper or lower beams, please keep in mind our safety concerns about glare. We intend to study this question in the coming months as part of a petition from the Japanese Automotive Parts Industry Association, and would appreciate any data you may have on this subject. Sincerely, |
1999 |
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