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 |
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ID: nht71-5.60OpenDATE: 09/14/71 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Cabot Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letters of March 10 and July 1, 1971, requesting an exemption from Motor Vehicle Safety Standard No. 117 for experimental tires that you manufacture by buffing off the tread of new tires and then recapping the tires with different compounds. You state that you use these tires for testing carbon blacks by testing the tires on the public highways and on private test tracks. We do not consider tires manufactured by the method you describe to be retreaded tires within the scope of Standard No. 117 because they are not manufactured from used tires. However, we do consider them to be new pneumatic tires, and subject to the requirements of Motor Vehicle Safety Standard No. 109. We regret that an earlier letter to you of April 7, 1971, may have been misleading in that regard. Section 108(a)(1) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. @ 1397(a)(1)) provides that no person shall -- "manufacture for sale, sell, offer for sale, or introduce or deliver for introduction in interstate commerce . . . any motor vehicle or item of motor vehicle equipment manufactured on or after the date any applicable Federal motor vehicle safety standard takes effect . . . unless it is in conformity with such standard." We consider the testing of these tires on the public roads to be an introduction of them in interstate commerce, and prohibited by section 108(a)(1) unless the tires conform to Standard No. 109. The tires need not be manufactured for sale to the general public in order for violations of section 108(a)(1) to occur. However, if the testing of these tires is confined to the laboratory or to private roads, the prohibition of the section 108(a)(1) will not apply to them. A copy of the Act and Motor Vehicle Safety Standard No. 109 is enclosed for your information. Enclosures |
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ID: nht71-5.61OpenDATE: 09/15/71 FROM: AUTHOR UNAVAILABLE; C. A. Baker for E. T. Driver; NHTSA TO: E. R. Buske Mfg. Co., Inc. TITLE: FMVSS INTERPRETATION TEXT: Your letter of September 3, 1971, to the Bureau of Motor Carrier Safety concerning the mounting of lamps on a body backplate has been referred to this Office for consideration and reply. Federal Motor Vehicle Safety Standard No. 108 requires that lamps meet the applicable SAE Standards (including the photometric specifications) when tested as mounted on the vehicle. (See SAE J575c, Paragraph J.) The maximum angle from a line perpendicular to the longitudinal centerline of the vehicle that a lamp can be mounted and meet the applicable requirements depends upon the design and configuration of the lamp. We therefore recommend that you contact the manufacturer of your lamps for this maximum angle information. |
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ID: nht71-5.62OpenDATE: 11/11/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Tire Review TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of August 10 and October 6, 1971, concerning the size requirements for retreaded tires as specified in Federal Motor Vehicle Safety Standard No. 117. Your letter of August 10 enclosed a draft article that you requested we examine. I have enclosed a copy of the Administration's action on the petitions for reconsideration that were received in response to the standard as published April 17, 1971 (36 F.S. 7315). This action amends the size requirements of 25.12 of the standard by allowing a minus 3 per cent deviation from the section width specified in Table 1 of Appendix A of Standard No. 109 in addition to the plus 10 per cent deviation previously allowed. With reference to your draft article, its discussion of the size requirements, apart from the changes made by the amendments, is accurate. The copies of Appendix A or Standard No. 109 that you were furnished on August 20 have been supplemented, and a copy of the additional material is also enclosed. WE ARE PLEASED TO BE OF ASSISTANCE. ENCLS. |
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ID: nht72-3.48OpenDATE: 10/18/72 FROM: AUTHOR UNAVAILABLE; Robert L. Carter; NHTSA TO: Mr. Charles E. West TITLE: FMVSS INTERPRETATION TEXT: Your letter of September 18, 1972, to Senator Warren G. Magnuson, Chairman, Committee on (Illegible Words) your automatic seat belt system has been referred to this office for reply. Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection, (copy enclosed) requires complete passive restraint systems in cars manufactured after August 15, 1973. This standard, as well as most of our standards, is written in performance terms and does not require the use of any specific device. Manufacturers are free to employ any system that will meet the requirements of the standard without any voluntary section on the part of the occupant, such as fastening a seat belt. The National Highway Traffic Safety Administration is not generally engaged in hardware development, but rather, directs its research efforts toward the development of technical data to form the basis for motor vehicle safety performance standards. Perhaps you might care to contact vehicle manufacturers to see if they would be interested in your automatic belt system. I am placing a copy of your letter in our Public Docket No. 69-7, which contains information relative to occupant restraint systems. We appreciated receiving the description of your system and your interest in motor vehicle safety. |
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ID: nht72-3.49OpenDATE: 09/05/72 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Volkswagen of America, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of June 26, 1972, on the subject of the conformity of the Volkswagen shoulder belt/knee bar system to the requirement of Standard No. 208. I apologize for our delay. Your first question is whether the system would meet the requirements for a fully passive system under S4.1.2.1 and S4.1.3 if it were adjusted automatically and met the frontal and lateral crash protection requirements if S5.1 and S5.2 and if the vehicle conformed to Standard 216. Our reply is that a passive seat belt system of the type you describe would appear to satisfy the requirements of S4.1.2.1 and S4.1.3. It would also, however, be required to meet the requirements of S4.5.3. We cannot determine from your description whether the system is capable of fitting the range of occupants specified in S7.1, as required by S4.5.3.3. Your second question concerns the possibility that the system could be used, with the shoulder belt either active or passive, to meet the second or third option for passenger cars manufactured between August 15, 1973, and August 15, 1975. You point to two variances between the Volkswagen system and the system contemplated by these options. S4.1.2.2 requires the installation of a Type 1 seat belt, whereas the Volkswagen system contains only a shoulder belt and a knee bar. S4.1.2.3 specifies either a Type 1 or a Type 2 seat belt assembly, neither of which is found in the Volkswagen system. It is our opinion that these variances are such that an amendment of the standard would be required to permit the use of the Volkswagen system under either S4.1.2.2 or S4.1.2.3. With reference to both the passive system discussed in your first question and a petition for rulemaking in connection with your second, we are particularly concerned with the actual crash performance of a single diagonal belt restraint as opposed to the Type 1 or Type 2 belts permitted in Standard No. 208. The injury criteria presently included in Standard No. 208 may not differentiate between restraint systems with good crash force distribution, such as the air cushion, and those such as the single diagonal belt which could poorly distribute loads on real human occupants. Accordingly, we would appreciate your sending us accident data describing experience with the European type single diagonal belt. |
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ID: nht72-3.5OpenDATE: 06/08/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Labelmaster TITLE: FMVSS INTERPRETATION TEXT: In response to your letter of May 11, 1972, submitting sample labels for retreaded tires, the samples which you submit, with the appropriate information properly filled in or clearly indicated by an "X" or other mark, will meet the requirements of S6.2 and S6.3 of Standard No. 117. |
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ID: nht72-3.50OpenDATE: 11/27/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Toyota Motor Sales, U.S.A., Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of October 2, 1972, concerning the requirements applicable to a seat belt installed as part of a restraint system conforming to S4.1.2.3 of Standard 208. You are correct in reading S4.1.2.3 to provide that a seat belt capable of meeting the injury criteria of Standard 208 is not required to meet Standard 209 except as provided in S7.1 and S7.2 of Standard 208. We have under consideration a petition from the Japan Automobile Manufacturers Association to amend Standard 209 to reflect the exemption made in Standard 208. The agency's response to the petition will be issued shortly. |
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ID: nht72-3.6OpenDATE: 02/01/72 FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA TO: Dunlop Limited TITLE: FMVSS INTERPRETATION TEXT: This will acknowledge your letter of January 14, 1972, to Mr. Douglas (Illegible Word), Administrator, National Highway Traffic Safety Administration, concerning the language of S5.1.2 of Federal Motor Vehicle Safety Standard No. 117. We concur with your comments that taken literally, the tolerance of -9% and -10% for the section width could be misinterpreted. We are placing your comments into the Docket and and editorial revision will be considered in future amendments to the standard. |
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ID: nht72-3.7OpenDATE: 11/14/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Nissan Motor Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of September 13, 1972, on the subject of S3.5.1(b) of Motor Vehicle Safety Standard No. 201. The terms "energy absorbing material" and "rigid material", as used in Standard 201, are not rigorously defined. According to your letter, the material used in the arm rest can be depressed to within 1.25 inches of the test surface by an evenly distributed force that does not exceed 100 pounds per square inch. This force does not appear to be excessive, and we would therefore consider the material to be "energy absorbing material". The "rigid material" with which contact is prohibited at distances greater than 1.25 inches from the test surface would include such components as brackets, channels and braces, most of which are commonly metallic. We do not rule out the possibility that in some instances a metallic component may be used expressly to absorb energy, but in the usual case a metallic part would be considered "rigid material" and contact with it would result in violation of S3.5.1(b). TRULY YOURS, NISSAN MOTOR CO., LTD. September 13, 1972 Lawrence R. Schneider National Highway Traffic Safety Administration Dear Mr. Schneider: Subject: Interpretation of MVSS 201; Occupant Protection In Interior Impact This is to ask your interpretation of MVSS 201; S3.5.1(b) (armrests) which states, "It shall be constructed with energy absorbing material* that deflect or collaspses to within 1.25 inches of . . .without permitting contact with any rigid material. '* is not distinguishable, therefore the following is our own interpretation: a) If the surface pressure which is calculated from the load equivalent to deflection 1.25 inches on the load-deflection curve measured during the test as shown in Figure 1, is not more than 100 pounds per square inch, we consider the tested material as the energy absorbing material. b) We consider metalic material as rigid material. If you feel you could improve upon the above, your prompt reply would be greatly appreciated. * The underscoring is for your personal reference. Tatsuo Kato Engineering Representative Liaison Office in USA [GRAPHICS OMITTED] |
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ID: nht72-3.8OpenDATE: 05/10/72 FROM: AUTHOR UNAVAILABLE; John Womack; NHTSA TO: Dockets TITLE: FMVSS INTERPRETATION |
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.