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: nht71-2.41OpenDATE: 05/05/71 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Jacob P. Billig, Esq. TITLE: FMVSS INTERPRETATION TEXT: In response to your letter of April 16, 1971, it is our opinion that the placement of the 2 1/4-inch-wide orange reflex reflector striping material on motor vehicles, in the manner shown in Exhibit A of your letter, would not impair the effectiveness of lamps, reflective devices, and associated equipment required by Federal Motor Vehicle Safety Standard No. 108, and would not be prohibited by that standard. |
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ID: nht71-3.29OpenDATE: 07/13/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Volkswagen of America, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your petition for rulemaking of June 28, 1971. You requested that Standard No. 208 be amended to allow the seat belt warning switch to be installed in the buckle instead of the retractor. The action on petitions for reconsideration issued on July 2, 1971, in effect granted your request, allowing the warning shut-off to be keyed to webbing withdrawal or buckle closure. |
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ID: nht71-3.50OpenDATE: 07/27/71 FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA TO: Ichikoh Industries, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your inquiry of July 16, 1971, concerning supplemental mirrors. Federal Motor Vehicle Safety Standard No. 111 does not prohibit the installation of a supplemental outside mirror on the passenger's side. The Standard does stipulate certain field of view requirements for both the inside and driver's outside mirror, but the manufacturer is certainly free to exceed these field of view requirements with additional mirrors. |
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ID: nht71-4.21OpenDATE: 10/15/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Dow Chemical Europe, S.A. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of September 24 to Francis Amstrong regarding the effective date of the new Federal motor vehicle brake fluid standard, No. 116. The effective date of March 1, 1972, means that any vehicle manufactured on or after that date for sale in the United States must be equipped with brake fluid meeting Motor Vehicle Safety Standard No. 116. |
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ID: nht71-4.26OpenDATE: 10/21/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: British Standards Institution TITLE: FMVSS INTERPRETATION TEXT: Your letter of 4 October 1971 encloses drawings of several seat belt buckle installations that show the locations at which you propose to apply the buckle crash forces specified in Standard No. 209. As to each of the buckles depicted, we consider the force lines to be correctly drawn for purposes of the buckle crash test. Please advise us if we can be of further assistance. |
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ID: nht80-3.7OpenDATE: 06/23/80 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Mr. William Tierney TITLE: FMVSS INTERPRETATION TEXT: This is to follow-up on your phone conversation of June 10, 1980, with Stephen Oesch of this office concerning the Federal requirements applicable to the installation of auxiliary fuel tanks in passenger cars. I am enclosing a copy of a letter of interpretation the agency issued last August which discussed the general implication of such installations under Federal law. If after reviewing this material you have any additional questions, please contact Mr. Oesch. |
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ID: nht73-6.24OpenDATE: November 26, 1973 FROM: Robert R. Aronson -- President, Electric Fuel Propulsion Corp. TO: Lawrence Schneider -- Chief Counsel, NHTSA TITLE: None ATTACHMT: Attached to letter dated 12/10/73 from Richard B. Dyson to Robert R. Aronson TEXT: In reference to FMVSS 301, our electric cars are equipped with a 2-quart gasoline tank which powers a Stewart Warner Water Heater for heating and defrosting cars. The location of the gas tank and heater is in the rear of the car. Please let us know if Standard 301 applies to this gas tank. |
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ID: nht78-3.30OpenDATE: 12/13/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Cars & Concepts, Inc. TITLE: FMVSS INTERPRETATION TEXT: This responds to your December 4, 1978, letter concerning the applicability of Safety Standard No. 205, Glazing Materials, to applied windshield tint bands. I am enclosing copies of two previous letters of interpretation by the agency regarding polyester films that appear to be similar to the product you describe. I think these letters will answer all of your questions. If not, please contact Hugh Oates of my office at 202-426-2992. |
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ID: nht76-1.12OpenDATE: 01/06/76 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Nissan Motor Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This responds to Nissan's December 12, 1975, question whether a manufacturer may comply with the requirement of Standard No. 105-75, Hydraulic Brake Systems, for "a lens labeled in letters" (S5.3.5) by means of painting or otherwise printing the required label directly onto the lens. The answer to your question is yes. Section S5.3.5's requirement for "a lens labeled in letters" permits labeling by means of printing directly on the lens itself. |
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ID: nht69-2.32OpenDATE: 12/09/69 FROM: AUTHOR UNAVAILABLE; C. A. Baker; NHTSA TO: Commonwealth of Pennsylvania TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of November 10, 1969, to the Federal Highway Administration concerning flashing side marker lamps. Paragraph S3.5 of Federal Motor Vehicle Safety Standard No. 109 within the flashing of side marker lamps simultaneously with the turn signal lamps on the side to which a turn is contemplated. There is no requirement in Standard No. 109 that these lamps must meet(Illegible Words) "Side Turn Signal Lamps," when used in this manner. |
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.