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.”
Search Tool
NHTSA's Interpretation Files Search
| Interpretations | Date |
|---|---|
ID: 1985-01.30OpenTYPE: INTERPRETATION-NHTSA DATE: 02/12/85 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Addressee not given TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of August 30, 1984, (not received until 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 not 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 any 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 the 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 the 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 submitted 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. |
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ID: nht80-3.15OpenDATE: 07/07/80 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: BMW of North America, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of June 9, 1980, asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108 with respect to the spacing required between headlamps and turn signal lamps on motorcycles. You cited Table IV of Standard No. 108 which requires that the "minimum edge to edge separation distance between [turn signal] lamp and [headlamp] is 4 inches." You also cited paragraph 4.2 of the referenced SAE standard on turn signal lamps, J588e, which mandates that "the optical axis (filament center) of the front turn signal shall be at least 4 inches from the inside diameter of the retaining ring of the headlamp unit providing the lower beam." Finally, you have cited an agency interpretation of November 5, 1979, to Bajaj Auto Limited as support that the provisions of 4.2 prevail, and you asked for confirmation of this opinion. The Bajaj letter does not provide the support you seek. The interpretation it provides is that the separation distance must be not less than the minimum under all motorcycle operating conditions. We view Table IV as controlling in this instance as it contains a specific locational requirement for motorcycles. Since that specific requirement is lacking in Table IV for other motor vehicle, paragraph 4.2 of J588e would then apply with respect to separation distance for lamps on passenger cars, trucks, buses, and multipurpose passenger vehicles. SINCERELY, BMW OF NORTH AMERICA, INC. June 9, 1980 Chief Counsel National Highway Traffic Safety Administration U.S. Department of Transportation RE: Request for Interpretation FMVSS 108, Lamps, Reflective Devices, and Associated Equipment Dear Sir We request interpretation of the interlamp spacing requirements specified for motorcycles in Table IV of FMVSS 108. A four-inch spacing is required between turn signal lamps and the edge of the headlamp in front, and between turn signal lamps in the rear. However, while subject table uses the words, "edge to edge", SAE J588e, referenced in Table III, specifies measuring turn signal distance from the filament center. Acceptance of the filament center of a turn signal lamp as the measuring point is underscored by your letter of November 5, 1979 to Mr. Keshav of Bajaj Auto Limited. A closely related question concerns the method of measurement, i.e., whether the required four-inch separation dimension is a physical measurement between lamps or a distance between lamp projections. This is questioned because the measurement method is not specified in Table IV, and because S4.3.1.1 of the standard, and section 4.3 of SAE J588e otherwise require unobstructed photometric compliance. In view of the above, we interpret the standard to mean that the four-inch dimension is a physical measurement to a turn signal's filament. We would appreciate receiving your interpretation as soon as convenient. Karl-Heinz Ziwica, Manager Safety & Emission Control Engineering |
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ID: nht71-1.42OpenDATE: 07/22/71 FROM: E. T. DRIVER -- NHTSA OFFICE OF OPERATING SYSTEMS MOTOR VEHICLE PROGRAMS TO: LOUIS C. LUNDSTROM -- DIRECTOR, AUTOMOTIVE SAFETY ENGINEERING GENERAL MOTORS ENVIRONMENTAL STAFF TITLE: NONE TEXT: Dear Mr. Lundstrom: This is in reply to your letter of July 12, 1971, to Mr. Douglas W. Toms, Acting Administrator, concerning replacement equipment covered in FMVSS No. 108, effective January 1, 1972. The requirements for original and replacement equipment in FMVSS No. 108 cover those items listed in Tables I and III, namely: Headlamps Turn signal operating units Tail lamps Turn signal flashers Stop lamps Vehicular hazard warning signal License plate lamps operating units Reflex reflectors Vehicular hazard warning signal Parking lamps flashers Side marker lamps Identification lamps Backup lamps Clearance lamps Turn signal lamps Intermediate side marker lamps Intermediate reflex reflectors In addition the requirements cover the following items specified in the text of the standard: School bus warning lamps Headlamp beam switching devices Headlamp upper beam indicator lamps Turn signal pilot indicator lamps Hazard warning signal pilot indicator lamps Plastic lenses Sincerely, |
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ID: 1985-01.49OpenTYPE: INTERPRETATION-NHTSA DATE: 03/15/85 FROM: AUTHOR UNAVAILABLE; Jeffrey R. Miller; NHTSA TO: Mr. M. Iwase TITLE: FMVSS INTERPRETATION TEXT:
March 15, 1985 Mr. M. Iwase Manager, Technical Administration Dept. Koito Manufacturing Co., Ltd. Shizuoka Works 500, Kitawaki Shimizu-shi, Shizuoka-ken Japan Dear Mr. Iwase: This is in reply to your letter of February 1, 1985, with reference to the compliance with Motor Vehicle Safety Standard No. 108 of a proposed motorcycle headlamp design. In the design shown in your letter a single housing would contain two dual-filament bulbs, each with an independently aimed reflector. You have stated that the headlamp can comply with the photometric requirements of Sae J584 when either compartment is lit, and that the assembly will meet all other requirements of J584. A dual bulb arrangement in a single housing is considered a single headlamp, and therefore its compliance will be judged when both compartments are lit to provide either the upper or lower beam. Assuming that when both compartments are lit the combined candlepower at individual test points does not exceed the maxima imposed by J584 for those test points, your design appears to comply with Standard No. 108. Sincerely, Original Signed By Jeffrey R. Miller Chief Counsel |
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ID: aiam4843OpenMr. Delbert N. Pier Legislation and Compliance Coordinator Hyundai America Technical Center, Inc. 5075 Venture Drive Ann Arbor, MI 48108; Mr. Delbert N. Pier Legislation and Compliance Coordinator Hyundai America Technical Center Inc. 5075 Venture Drive Ann Arbor MI 48108; Dear Mr. Pier: This is in reply to your letter of February 11, l99l asking for an interpretation of Motor Vehicle Safety Standard No. 108. With respect to a contemplated headlamp design using a standardized replaceable light source, you have asked 'whether the bulb fixture can be rotated approximately 11 degrees', and have informed us that this will not change the 'constants . . . or the relationship of the terminals to the constants.' Standard No. 108 does not specify the orientation of replaceable light sources in headlamps, the socket in the reflector may be in any orientation. In the configuration you present, for the bulb assembly, the terminals appear to remain perpendicular to the base and parallel within plus or minus 1.5 degrees as required in Figure 3-3. The rotation of the socket (in the reflector) of Figure 3-7, is not regulated and, therefore, is acceptable under Standard No. 108. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: nht90-4.94OpenTYPE: Interpretation-NHTSA DATE: December 24, 1990 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Herr T. Spingler TITLE: None TEXT: This is in reply to your FAX of July 19, 1990, to Richard Van Iderstine of this agency asking for confirmation of an oral interpretation provided you by Jere Medlin, Office of Rulemaking, with respect to replaceable bulb headlamps. Motor Vehicle Safety Standard No. 108, Lamps, Reflective Devices, and Associated Equipment, defines (section S3) a replaceable bulb headlamp as "a headlamp comprising a bonded lens and reflector assembly and one or two standardized replaceable light sour ces." In Europe you fix the lens to the reflector assembly with a rubber seal and clips. For the U.S. market you propose to add "silicone-glue at four places between lens and housing to prevent removal of the lens." Mr. Medlin informed you that this w ould be a "bonded lens and reflector assembly." The standard does not define "bonded", but the intent of the definition is that, once the lens is joined to the reflector assembly, it shall not be separable. Any method of adhesion that accomplishes this would be a sufficient bond for purposes of the d efinition. If the application of silicone glue at four places between the lens and the reflector assembly is sufficient to prevent manual separation of the lens from the assembly, then it would be a sufficient bond. I hope that this answers your question. |
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ID: 11435ZTVOpen Herr Tilman Spingler FAX 49-7121-35-1792 Dear Herr Spingler: We have received your FAX of December 18, 1995, asking whether it is permissible under Motor Vehicle Safety Standard No. 108 "to achieve both high- and lowbeam of a headlamp with only one single light source?" If the answer is yes, you would like to know which photometric requirements are applicable, saying that, in any event, it will meet the photometric requirements of any beam in which it is operated. Use of a single light source (which we interpret to mean a single replaceable light source with a single filament) to provide both beams is not prohibited. While not specifically identified, it is permissible in either integral beam headlighting systems specified in paragraph S7.4 of Standard No. 108 or replaceable bulb headlighting systems of S7.5. Each such headlamp in a two-headlamp system is required by S7.4(a)(2) to be designed to conform to the photometrics of Figure 17A or Figure 27 for integral beam systems, or either Figure 17A or Figure 27 for replaceable bulb systems, depending on the type of light source used. If this is a new type of replaceable light source, the relevant information required by Part 564 for such light sources would need to be submitted in advance of its use, in accordance with that regulation. If you have any questions, you may refer them to Taylor Vinson of this Office. Sincerely,
Samuel J. Dubbin Chief Counsel ref:108 d:1/29/96 |
1996 |
ID: nht90-3.44OpenTYPE: Interpretation-NHTSA DATE: August 2, 1990 FROM: Paul Jackson Rice, NHTSA TO: T. Spingler, Robert Bosch GmbH TITLE: None ATTACHMT: Letter dated 7-19-90 to R. v. Iderstine from T. Spingler; (OCC 5014) TEXT: This is in reply to your FAX of July 19, 1990, to Richard Van Iderstine of this agency asking for confirmation of an oral interpretation provided you by Jere Medlin, Office of Rulemaking, with respect to replaceable bulb headlamps. Motor Vehicle Safety Standard No. 108, Lamps, Reflective Devices, and Associated Equipment, defines (section S3) a replaceable bulb headlamp as "a headlamp comprising a bonded lens and reflector assembly and one or two standardized replaceable light sour ces." In Europe you fix the lens to the reflector assembly with a rubber seal and clips. For the U.S. market you propose to add "silicone-glue at four places between lens and housing to prevent removal of the lens." Mr. Medlin informed you that this w ould be a "bonded lens and reflector assembly." The standard does not define "bonded", but the intent of the definition is that, once the lens is joined to the reflector assembly, it shall not be separable. Any method of adhesion that accomplishes this would be a sufficient bond for purposes of the d efinition. If the application of silicone glue at four places between the lens and the reflector assembly is sufficient to prevent manual separation of the lens from the assembly, then it would be a sufficient bond. I hope that this answers your question. |
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ID: 2778yOpen Herr T. Spingler FAX 07121/35-1792 Dear Herr Spingler: This is in reply to your FAX of July l9, l990, to Richard Van Iderstine of this agency asking for confirmation of an oral interpretation provided you by Jere Medlin, Office of Rulemaking, with respect to replaceable bulb headlamps. Motor Vehicle Safety Standard No. l08, Lamps, Reflective Devices, and Associated Equipment, defines (section S3) a replaceable bulb headlamp as "a headlamp comprising a bonded lens and reflector assembly and one or two standardized replaceable light sources." In Europe you fix the lens to the reflector assembly with a rubber seal and clips. For the U.S. market you propose to add "silicone-glue at four places between lens and housing to prevent removal of the lens." Mr. Medlin informed you that this would be a "bonded lens and reflector assembly." The standard does not define "bonded", but the intent of the definition is that, once the lens is joined to the reflector assembly, it shall not be separable. Any method of adhesion that accomplishes this would be a sufficient bond for purposes of the definition. If the application of silicone glue at four places between the lens and the reflector assembly is sufficient to prevent manual separation of the lens from the assembly, then it would be a sufficient bond. I hope that this answers your question. Sincerely,,
Paul Jackson Rice Chief Counsel ref:l08 d:l2/24/90 |
1990 |
ID: 2632yOpen Mr. Herr T. Spingler FAX 07121/35-1792 Dear Herr Spingler: This is in reply to your FAX of July l9, l990, to Richard Van Iderstine of this agency asking for confirmation of an oral interpretation provided you by Jere Medlin, Office of Rulemaking, with respect to replaceable bulb headlamps. Motor Vehicle Safety Standard No. l08, Lamps, Reflective Devices, and Associated Equipment, defines (section S3) a replaceable bulb headlamp as "a headlamp comprising a bonded lens and reflector assembly and one or two standardized replaceable light sources." In Europe you fix the lens to the reflector assembly with a rubber seal and clips. For the U.S. market you propose to add "silicone-glue at four places between lens and housing to prevent removal of the lens." Mr. Medlin informed you that this would be a "bonded lens and reflector assembly." The standard does not define "bonded", but the intent of the definition is that, once the lens is joined to the reflector assembly, it shall not be separable. Any method of adhesion that accomplishes this would be a sufficient bond for purposes of the definition. If the application of silicone glue at four places between the lens and the reflector assembly is sufficient to prevent manual separation of the lens from the assembly, then it would be a sufficient bond. I hope that this answers your question. Sincerely,,
Paul Jackson Rice Chief Counsel ref:l08 d:8/2/90 |
1990 |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.