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: nht71-5.14OpenDATE: 12/06/71 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Seats, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of October 4, 1971, in which you asked our opinion as to whether Standard No. 207 permits a suspension type truck seat with fore and aft adjustment to be equipped with seat belt type webbing from the seat to the floor. It is our position that such webbing may be used to provide the strength required by Standard No. 207 and that a seat so equipped must conform to S4.2(c) of the standard (unless, as seems unlikely, the occupant's seat belt is anchored to the floor and not to the seat). Instructions for the adjustment of the seat to floor webbing are essential to the safe operation of such a system, however, and should be provided. I apologize for any inconvenience that our delayed response may have caused you. |
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ID: nht71-5.17OpenDATE: 12/09/71 FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA TO: Import-Export TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of November 20, 1971, to Mr. Franklyn Bergsman, National Highway Traffic Safety Administration, concerning your "Flash Mirrors." As described in the documents you furnished to us, your "Flash Mirror" does not appear to impair the effectiveness of the required lighting equipment. If this is indeed the case, the use of your "Flash Mirrors" as original vehicle equipment is not prohibited by the Federal Motor Vehicle Safety Standard No. 108. Nor is there a Federal prohibition against sale of your device in the aftermarket; Standard No. 108 covers only specified replacement lighting equipment for vehicles manufactured on or after January 1, 1972. Since your product is not regulated by Standard 108, the sale and use of it is, however, subject to the regulations of the individual States. |
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ID: nht71-5.28OpenDATE: 12/23/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Volkswagen of America, Inc. TITLE: FMVSS INTERPRETATION TEXT: Your letter of July 2, 1971, points out an apparent conflict within the upper torso seat belt anchorage location requirement of standard No. 210. The conflict is between the provision of S4.3.2 that the range of permissible locations is established with the seat back in its most upright position and the provision that the 2 dimensional manikin shall have its "H" point on the seating reference point. The manikin's "H" point may not be capable of being positioned on the seating reference point if the manufacturer has used a "nominal design riding position" other than the "most upright position" in establishing the seating reference point. We agree that the conflict exists and intend to eliminate it by appropriate amendment in the Federal Register. We will advise you upon issuance of the amendment. |
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ID: nht72-4.1OpenDATE: 08/31/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: General Motors Technical Center TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of August 21, 1972, on the subject of the operation of the seat belt warning system when the vehicle is in one of the free start modes allowed by S7.4.3 and S7.4.4 of Standard No. 208. You are correct in your understanding that S7.3.5.4 does not require the warning to operate when the ignition switch is in the "start" position if the conditions described in S7.4.3 and S7.4.4 exist. Under those conditions, the interlock system continues to act as if the operation of the belt systems had not been followed by their release. By the same logic, the warning system activation required by S7.3.5.4 is in abeyance until the ending of the free start conditions. |
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ID: nht72-4.15OpenDATE: 07/05/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Nissan Motor Co. Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of June 20, 1972, on the subject of the options which may be included in the unloaded vehicle weight of a passenger car under S8.1.1 of Standard 208. The definition of "unloaded vehicle weight" is intended to include a vehicle equipped with any combination of optional items that are installed by the factory or by the dealer with the factory's authorization. The weight of equipment installed by the dealer without authorization by the manufacturer would not be includable. To answer your question by use of your example, you must concern yourself with both factory optional air conditioning and with dealer optional air conditioning that is authorized by the factory. |
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ID: nht72-4.17OpenDATE: 02/01/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Borg-Warner Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your request of January 18, 1972, for a letter confirming the written interpretation of Standard 209 concerning automatic locking retractors given to Toyota on November 10, 1971. We understand from your letter that the "Borg-Warner Maji-Buckle" is identical to the combination buckle and retractor shown us by Toyota. A seat belt with the Maji-Buckle" is, therefore, considered to be equipped with an automatic locking retractor. A retractor is classified according to its operation, not its design, and the "Maji-Buckle" operates in the manner prescribed by Standard 209 for automatic locking retractors. The comments made to Toyota concerning the test required by S5.3(a)(6) also apply to the "Maji-Buckle." Please advise us if we can be of further assistance. |
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ID: nht72-4.3OpenDATE: 09/20/72 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Docket 69-7 TITLE: FMVSS INTERPRETATION TEXT: SUBJECT: Interpretation of Dummy Placement for Crash Test Requirements of S4.1.2.3.1(d) and (e). A Ford Motor Company representative has informally noted that Docket 69-7, Notice 16, published February 24, 1972, does not clearly indicate whether, in S4.1.2.3.1(d) and (e), three dummies are simultaneously placed in all front seating positions for a single crash test, or whether two separate crashes are conducted, with two dummies in the outboard front seats for a S4.1.2.3.1(d) crash and a single dummy in the center front seat for a S4.1.2.3.1(e) crash. Although a manufacturer may choose, for reasons of convenience, to conduct a combined crash test or individual crash tests for S4.1.2.3.1(d) and (e), the test intended by S4.1.2.3.1 is a combined test and the NHTSA will therefore conduct its compliance tests with dummies simultaneously placed in all front seating positions. |
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ID: nht73-3.41OpenDATE: 03/08/73 FROM: AUTHOR UNAVAILABLE; Robert L. Carter; NHTSA TO: Mrs. Gussie Peer TITLE: FMVSS INTERPRETATION TEXT: Your recent letter to the National Transportation Safety Board concerning bus window glass has been referred to me for reply. Safety glazing in buses is regulated by Federal Motor Vehicle Safety Standard No. 205. In general, the windows in the vicinity of passengers may be either laminated safety glass or tempered safety glass, or rigid plastics, if the windows are readily removable. Hence, the Federal standard does not prohibit manufacturers from using glazing materials that perform as you suggest. In the past few years, manufacturers have expressed interest in providing passengers with protection from missiles thrown at buses. I expect to see an increase in the use of materials that conform with your suggestion. I am enclosing a summary of the Federal Motor Vehicle Safety Standards for your information. |
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ID: nht73-4.39OpenDATE: 07/30/73 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Mr. Barry Kulik TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 18, 1973, concerning the method of testing the sensitivity of seat sensors under sections S7.3 and S7.4 of Federal Motor Vehicle Safety Standard No. 208. The relevant characteristics of the "person" referred to in these sections are found in the weight and dimension table of Section S7.1.3 of the standard. Our testing laboratory will, in all likelihood, be using test dummies purchased from the various commercial dummy manufacturers, whose weights and dimensions conform to S7.1.3 of the standard. Human volunteers could be used, but the dimensional controls are difficult to maintain and we do not regard liver persons as a practical means of testing sensors under the standard. |
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ID: nht73-4.8OpenDATE: 04/11/73 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Fiat Motor Company, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 22, 1973, requesting confirmation of your understanding that automobile manufacturers may continue to use glazing materials manufactured before April 1, 1973, that do not conform to the recent amendment to Standard No. 205, "Glazing Materials", effective on that date, in motor vehicles manufactured after that date. Standard No. 205, an "equipment standard", applies to glazing materials for use in motor vehicles. It does not apply directly to vehicles in which such materials are used. As a consequence, a vehicle manufacturer may use glazing materials that do not conform to Standard No. 205 as it exists on the date the vehicle is manufactured. The glazing material must, however, conform to the standard as it exists on the date that the material is manufactured. |
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.