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: nht73-1.38OpenDATE: NOVEMBER 23, 1973 FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA TO: Mr. James C. Martin TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of November 9 to the U. S. Department of Transportation concerning the operation of 4-way flashers and brake lights on a 1972 Toyota. Since there is no requirement that the hazard warning signal (4-way flashers) be capable of operating independently of the stop signal, it is permissible for the stop signal to override the hazard warning signal. In fact, these signals on most passenger cars and multipurpose passenger vehicles manufactured in the United States operate similarly. |
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ID: nht73-2.36OpenDATE: 08/31/73 FROM: R. B. DYSON -- ACTING CHIEF COUNSEL, NHTSA; SIGNATURE BY DAVID SCHMELTZER TO: New York State Police TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter on August 20, 1973, asking that law enforcement vehicles be excluded from a Federal prohibition against headlight flashers. There is no such prohibition. While paragraph S4.6(b) of Federal Motor Vehicle Safety Standard No. 108 requires headlamps to be steady-burning in use, it also specifically states that "means may be provided to flash [automatically] headlamps . . . for signalling purposes." Therefore, manufacturers are not prohibited from equipping vehicles with headlamp flasher units upon customer request. |
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ID: nht75-1.20OpenDATE: 08/21/75 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Toyoda Gosei Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: Please forgive the delay in responding to your letter of April 25, 1975, which questioned our interpretation of March 13, 1975, of the adhesion requirement of S7.3.7 of Federal Motor Vehicle Safety Standard No. 106-74, Brake Hoses. Our interpretation was that the requirement applies to each pair of adjacent layers of a brake hose. Multilayer hose manufactured in the United States and Europe is in fact made with bonding between all pairs of adjacent layers. There is no change in our interpretation. |
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ID: nht75-2.13OpenDATE: 06/04/75 FROM: AUTHOR UNAVAILABLE; James C. Schultz; NHTSA TO: Volvo of America TITLE: FMVSS INTERPRETATION TEXT: Please forgive the delay in responding to your letter of March 24, 1975, requesting an interpretation of Federal Motor Vehicle Safety Standard No. 110, Tire Selection and Rims -- Passenger Cars. You have inquired whether the placard required by S4.3 of the standard may display information in addition to the items specified in S4.3(a) through (d). The NHTSA has no objection to such placarding, provided that the additional information is set apart from, not placed among, the required items. |
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ID: nht94-1.8OpenTYPE: Interpretation-NHTSA DATE: January 5, 1994 FROM: Stephen M. Monseu -- General Manager, Schroth Restraint Systems Corp. TO: Mary Versailles -- NHTSA TITLE: None ATTACHMT: Attached to letter dated 3/21/94 from John Womack to Wolf Ebel (A42; Redbook; Std. 208) TEXT: I would like to add one more request for response in addition to my previous letter. If one of our belt systems were installed as original equipment would they meet the provisions of FMVSS 208 and what would we have to do to remain in compliance? Your response will be greatly appreciated. |
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ID: nht69-1.28OpenDATE: 02/03/69 FROM: AUTHOR UNAVAILABLE; C. A. Baker; NHTSA TO: Toyota Motor Company, Ltd TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of December 4, 1968, to Mr. Eugene Laskin regarding Motor Vehicle Safety Standard No. 111 on rearview mirrors. Your interpretation and enclosed figure 1 are not entirely correct. The 35 foot distance is measured horizontally, not at an angle. The plane must be tangent to the vehicle -- not tangent to the mirror. The measurement is made at the road surface 35 feet to the rear of the projected eye position and 8 feet outward from this plane. |
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ID: nht68-3.22OpenDATE: 04/06/68 FROM: ROGER H. COMPTON -- NHTSA; SIGNATURE BY DAVID A. FAY TO: Green and Green Manufacturing Company TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of February 19, 1968, to Secretary Boyd, concerning the location of rear identification lamps on best trailers. Standard No. 108 permits rear identification lasts to be mounted at optional heights. Therefore, lamps mounted on extension brackets or add-on(Illegible Words) would be permissible. We would also point out that rear identification lamps are required only on those trailers that are 80 or more inches in overall width. Thank you for writing. |
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ID: nht71-2.31OpenDATE: 04/28/71 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Toyota Motor Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is to conform your understanding that the DOT symbol, which represents the tire manufacturer's certification that the tire complies with the passenger car tire standard, is required on tires installed on multipurpose passenger vehicles, if such tires are originally designed and have passenger car tire size designations. However, since Standard No. 110 does not, at the present time, apply to multipurpose passenger vehicles, the responsibility for assuring that these tires contain the DOT symbol is limited to the tire manufacturer. |
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ID: nht72-1.9OpenDATE: 11/06/72 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Paul Utans TITLE: FMVSS INTERPRETATION TEXT: In your letter of October 9, 1972, you enclosed a master brake cylinder cover ("Exhibit A"), and a reservoir label ("Exhibit B"), both produced by Alfred Teves, and asked our views as to their conformity with the lettering size and contrast requirements of paragraph S3.4.3 of Motor Vehicle Safety Standard No. 105a. These sample items appear to conform to the lettering requirements, with the exception that the cylinder cover of Exhibit A is the same color as the raised lettering, and does not provide a contrasting background as required by the standard. |
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ID: nht72-2.41OpenDATE: 02/28/72 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Dayton Steel Foundry Company TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 2, 1972, in which you asked whether the temperature range specified in S6.2.6 of Motor Vehicle Safety Standard No. 121 was an initial temperature range or a range applicable throughout the stop. In the new issuance of the standard, published in the February 24, 1972, issue of the Federal Register, the section has been amended to make it clear that the range is the range of initial brake temperature on each stop. |
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.