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: nht92-2.16OpenDATE: November 20, 1992 FROM: L. Schmidt TO: NHTSA TITLE: None ATTACHMT: Attached to letter dated 5-6-93 from John Womack to L. Schmidt (A41; Std. 301) TEXT: I am writing to obtain some information regarding changing engines in cars -- the questions are. 1. Is there any law that forbids replacing a worn out gas engine in a U.S. or foreign automobile with a diesel engine -- like a 6 cylinder Diesel Cummins engine which is in a Dodge pickup truck? (the 3/4 ton type) 2. If there is a law that forbids that -- does it only apply to the zone in a state where emissions tests are yearly required? Please let me know about this. I was told its possible there is a law on this. I would assume that the GM Diesel engine passenger cars could have engines switched to other better diesel engines if there was a law against switching the other way. Please let me know as we would like to know about this. |
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ID: nht91-6.3OpenDATE: September 18, 1991 FROM: Al Lipinski -- President, Mini-Max TO: Hall, Jackson, Rice -- NATSA (NHTSA), Chief Counsel TITLE: None ATTACHMT: Attached to letter dated 10-23-91 from Paul Jackson Rice to Al Lipinski (A38; Std. 108; Part 567) TEXT: I talked with Steve Kratzke on September 18, 1991 regarding the Dynamic Testing requirements for alterers of certified vehicles. We are a small conversion company of walk in van type light trucks located in Escanaba, MI. Our projected production for 1992 is 75 vehicles. We do not alter anything forward of the B pillar of a certified vehicle, thus the crash protection system installed by the original manufacturer is not disturbed. We afix an additional label stating the vehicle alterations conform to all applicable FMVSS. I would appreciate a letter stating what the dynamic testing requirements are for an alterer of a certified vehicle for my files in case this question arises in the future. |
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ID: 77-1.12OpenTYPE: INTERPRETATION-NHTSA DATE: 01/26/77 FROM: AUTHOR UNAVAILABLE; Frank A. Berndt; NHTSA TO: Nissan Motor Co. Ltd. TITLE: FMVSR INTERPRETATION TEXT: This will confirm your November 11, 1976, telephone conversation with Tad Herlihy of this office, concerning the certification label required by 49 CFR Part 567. On the vehicles in question, the certification labels mistakenly indicated 1977 as the year of manufacture, even though manufacturing was actually completed in 1976. You proposed correcting this error before sale by crossing out the digits "77" and inserting "76" directly below them. The National Highway Traffic Safety Administration has no objection to certification labels that have been corrected in this manner, provided that all other requirements of the certification regulation are also met. |
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ID: nht74-3.44OpenDATE: 05/14/74 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Oshkosh Truck Corporation TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of March 27, 1974, in which you ask whether a final-stage manufacturer who mounts a used body on a new chassis is required to certify the conformity of the completed vehicle in accordance with 49 CFR Parts 567, 568. The answer is yes. A person who mounts a used body on a new chassis is a final-stage manufacturer and is required to certify the conformity of the completed vehicle. The NHTSA has interpreted the Certification requirement as applying to any complete vehicle manufactured using a new incomplete vehicle (chassis) whether or not the body to be installed is new or used. |
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ID: nht68-3.38OpenDATE: 07/08/68 FROM: AUTHOR UNAVAILABLE; Joseph R. O'Gorman; NHTSA TO: Gypsy Campers TITLE: FMVSR INTERPRETATION TEXT: Thank you for your letter of May 29, 1968, in which you state that your camper conversion is not subject to the requirements of the Federal Motor Vehicle Safety Standards. Please note the requirements for glazing in Federal Motor Vehicle Safety Standard No. 205, contained in our letter to you dated May 24, 1968. Should your modification involve installation of glazing, then these requirements would apply. Note also Standards No. 103, 106, 107, 111, and 211, which are applicable to a multi-purpose passenger vehicle. Your conversion of a van to a camper is conversion of a truck to a multi-purpose passenger vehicle, and therefore, requires compliance with applicable standards. |
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ID: nht71-3.15OpenDATE: 06/08/71 FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA TO: Mercedes-Benz of North America, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your May 21, 1971, letter to Mr. H. H. Wallace to determine whether Dunlop is in compliance as to the use of spaces in the tire identification number. There are no objections to the spaces between the different parts of the number. However, the photograph illustrates other problem, that of a dual size marked tire. Dual size marked tires are not permissible. The tire can be labeled as one size tire with the indication that it replaces another size tire. For example, 205R14 replaces ER70-14. The General Secretary of ETRTO has been advised of the "dual marked" tire usage. |
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ID: nht68-2.14OpenDATE: 07/03/68 FROM: AUTHOR UNAVAILABLE; David A. Fay; NHTSA TO: Ideal Manufacturing Company TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of June 10, 1968, to Mr. J. O'Gorman of this Bureau, concerning the requirements for side reflex reflectors as specified in Federal Motor Vehicle Safety Standard No. 108. As noted in your letter, paragraph S3.1.1.6 of Standard No. 108, effective January 1, 1969, permits until January 1, 1970, the use of two side reflex reflectors on each side of vehicles that are less than 80 inches in overall width. On and after January 1, 1970, Standard No. 108 requires that these vehicles be equipped on each side with two side reflex reflectors and two side marker lamps. Thank you for writing. |
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ID: nht92-8.8OpenDATE: April 1, 1992 FROM: Charles Chun -- General Manager, Kia Motors TO: Paul Jackson Rice -- Chief Counsel, NHTSA TITLE: Re: S5. Dynamic Performance Requirements in FMVSS 214 - Side Impact Protection ATTACHMT: Attached to letter dated 5/22/92 from Paul J. Rice to Charles Chun (A39; Std. 214) TEXT: We would like to make clear the Manufactured Date in the captioned regulation. A) What does Manufactured Date exactly mean? Does it mean whether production date at Kia factory in Korea or the date of U.S Customs clearance ? B) Does it mean that Manufactured Date has the same meaning with the same Model Year? Appreciated your authoritative interpretation. Thank you. |
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ID: nht73-3.30OpenDATE: 02/20/73 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Canadian Pittsburgh Industries, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of December 22, 1972, which was forwarded to us by the Department of Transport of Canada, requesting assignment of a manufacturer's code number for glazing materials you manufacturer. In your letter you indicate that the glazing in question is purchased in stock sheets, and then out to the customer's requirements. The assignment of Code number is limited to what NHTSA has called "prime glazing material manufacturers" and this group includes only those who "fabricate, lauinate, or tamper the glazing material." As your function appears to be only that of cutting the material to size, we would not consider you, at least with respect to this material, to be a prime glazing material manufacturer. Consequently, a code number assignment would be improper. The labeling requirements which you would be subject to, if this glazing as cut by you is to be imported into the United States, are those requirements specified in S6.4 and S6.5 of Motor Vehicle Safety Standard No. 203, copy enclosed. |
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ID: nht94-4.4OpenTYPE: INTERPRETATION-NHTSA DATE: August 18, 1994 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Richard J Quigley TITLE: None ATTACHMT: Attachment dated 8/1/94: Fax from Richard Quigley to John Womack TEXT: This responds to your request for reconsideration of our July 15, 1994 interpretation letter on Standard No. 218, Motorcycle helmets. In that letter, we stated that a drawing you provided would not meet the requirement in S5.6.1(e) of the standard that m otorcycle helmets be labeled with the symbol DOT. You enclosed a new drawing and ask whether it meets S5.6.1(e). The answer is no. The new version of the drawing consists of three figures that you believe constitute the symbol "DOT." Your new drawing continues to incorporate a corporate logo in lieu of the letter "O." As explained in our July 15, 1994 letter, because the symbol DOT constitutes the manufacturer's certification that the helmet conforms to Standard No. 218, there must be no ambiguity in the symbol. Using the corporate logo in lieu of the letter "O" introduces ambiguity as to whether the manufacturer has certified the helmet. Thus, the new version of the drawing you provided does not meet S5.6.1(e) of Standard No. 218. I hope this answers your question. |
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.