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: nht68-2.6OpenDATE: 05/14/68 FROM: AUTHOR UNAVAILABLE; David A. Fay; NHTSA TO: White Motor Corporation TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of April 16, 1968, to Mr. Lowell K. Bridwell, Administrator, Federal Highway Administration, requesting a clarification of the electrical circuity arrangements that may be used to meet the requirements of paragraph S3.4.3 of Motor Vehicle Safety Standard No. 108. Truck-tractors wired in accordance with your customers' orders stating, "the brown trailer circuit shall be connected to the headlamp switch and the black trailer circuit shall be energized through a seperate switch," will meet the requirements of paragraph 53.4.3, provided the trailer circuits conform to SAE Standard J560a. With this circuitry, your responsibility as a truck-tractor manufacturer would be fulfilled, regardless of the number of trailers that are towed by the truck-tractor. Thank you for writing. |
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ID: nht68-3.39OpenDATE: 07/09/68 FROM: AUTHOR UNAVAILABLE; Robert M. O'Mahoney; NHTSA TO: Mr. Philips B. Boyer TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of June 24 to the Department of Transportation asking if manufacturers of motor homes are "required to equip the seats in such units with seat belts." The self-propelled motor home is classified as a "multipurpose passenger vehicle" for purpose of the Federal motor vehicle safety standards. Currently seat belt installations and seat belt assembly anchorages are not required for multipurpose passenger vehicles, but if a seat belt assembly is(Illegible Word) by the vehicle manufacturer it must meet the requirement of Federal standard No. 209. On October 14, 1967 the Federal Highway Administrator established dockets to receive comments on possible requirements for seat belt installations and seat belt assembly anchorages in multipurpose passenger vehicles. These comments are now under evaluation. |
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ID: nht68-4.14OpenDATE: 09/11/68 FROM: AUTHOR UNAVAILABLE; Robert M. O'Mahoney; NHTSA TO: Meyer Products, Inc. TITLE: FMVSS INTERPRETATION TEXT: I regret the delay in responding to your letter of April 23, in which you provided certain certification information and details on your wheeled spreaders. The wheeled spreaders attached to a towing vehicle are considered motor vehicles under the National Traffic and Motor Vehicle Safety Act of 1966, and have been categorized as "trailers". Federal Motor Vehicle Safety Standard No. 108 is currently the only Standard applicable to trailers, specifically those 80 inches and more in overall width. This Standard will also apply to trailers of lesserwidth manufactured after December 31, 1968. Accordingly Meyer Products is required to certify compliance in accordance with section 114 of the Act. I enclose for your guidance copies of the Act, Federal Standard No. 108, and the certification Notice currently in effect. |
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ID: nht70-2.29OpenDATE: 10/07/70 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Automobili Lamborghini TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of September 23 informing us of Lamborghini's continued progress towards compliance with Federal motor vehicle safety standards. I want to remind you that Standard No. 211 precludes the use of wheel nuts, wheel discs, and hub caps that incorporate winged projections, such as the one shown in the(Illegible Word) photograph which I enclose. We have seen several(Illegible Word) manufactured in 1969 with wheels identical to this one, and were informed in one instance that the winged projections had been shipped from Italy with the car. Such a shipment violates the spirit, if not the letter, of Standard No. 211. There is no charge for the "Program Plan for Motor Vehicle Safety Standards", enclosed at your request. |
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ID: nht70-2.37OpenDATE: 12/02/70 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Charles O. Verrill, Esq. TITLE: FMVSS INTERPRETATION TEXT: In your letter of November 16 you inquire whether the Bureau's interpretation of "overall width" (49 CFR @ 571.21, with reference to Federal Motor Vehicle Safety Standard No. 108) can "embrace the situation where the entire lighting assembly, including the taillamps, stop lamps, and back-up lamps, as well as signal lamps, add to the dimension of the vehicle". Since "overall width" means "the nominal design dimension of the widest part of the vehicle exclusive of signal lamps [and] marker lamps . . . .", the Bureau concurs in your requested interpretation. Taillamps, stop lamps, and back-up lamps are "signal" lamps, and their combined mounting in a fixture which may extend beyond the widest part of a boat trailer does not result in a corresponding increase in the "overall width" of the trailer. |
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ID: nht71-2.18OpenDATE: 03/23/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Hankscraft Company TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 4, 1971, in which you asked for an opinion as to whether the Hankscraft Child's Auto Safety Harness, Style 705, is a Type 3 seat belt assembly within the scope of Standard No. 209.(Illegible Word) harness sold for automobile use that is advertised as a safety harness(Illegible Words)(Illegible Word) not carefully state that it is not intended to project a child from the efforts of the(Illegible Word) is considered a Type 3 seat belt assembly that must conform to Standard No. 209. Since Hankscraft identifies its product as an "Auto Safety Harness" and states that it will provide "effective restraint . . . with increased safety in all but the most(Illegible Words) us would require the harness in question to conform to Standard No. 209. |
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ID: nht71-2.29OpenDATE: 04/20/71 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Morgan Motor Company TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of March 17, 1971, in which you requested further clarification of the test procedures of the standard on side door strength, Standard No. 214. Your diagram of the Morgan Plus 8 shows a horizontal line drawn across the door 5 inches above the lowest point of the door. This would appear to be an accurate depiction of the location of the lower edge of the loading device as specified in the standard. You express concern that the line is a considerable distance from the ground, but under the requirements of the standard, the height above the lower edge of the door is the relevant height, and not the height above ground. I hope this will help to resolve your questions with respect to Standard No. 214. |
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ID: nht71-5.66OpenDATE: 12/15/71 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Oshkosh Truck Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your telegram of December 9, 1971, in which you asked whether the effective dates of Standards 206, 207, 208, and 210 are postponed to January 1, 1974 for firefighting vehicles as a result of the adoption of the effective date provisions of 49 CFR 571.8 (36 F.R. 13926, July, 28, 1971). Our answer is that since all of the amendments making the listed(Illegible Words) to trucks were issued prior to the September 1, 1971 reference date used in 571.8, these standards are effective on the dates established at the time of their issuance. Versions of Standards 208 and 210 became effective for trucks on July 1, 1971, and amended version of these standards, as well as Standards 205 and 207 become effective January 1, 1972. Sincerely, |
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ID: nht72-1.23OpenDATE: 06/28/72 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Rubber Manufacturers Association TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of June 9, 1972, asking whether the National Traffic and Motor Vehicle Safety Act prompts the various States from enforcing the Vehicle Equipment Safety Commission's Regulation V-1 with respect to passenger car tires. Section 103(d) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1392(d) requires any State law applicable to the same aspect of motor vehicle performance as a Federal motor vehicle safety standard to be identical to the Federal standard. We believe this section, considered in light of Federal Motor Vehicle Safety Standard No. 109, invalidates any State law that requires passenger car tires (except tires procured by a State for its own use) to meet the VESC Regulation V.1, or to be labeled with the V-1 symbol. |
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ID: nht72-1.28OpenDATE: 01/19/72 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: The Kelley-Springfield Tire Company TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of November 18, 1971, concerning the use of the word "fits" in the secondary size stamping on the sidewall of Kelley-Springfield manufactured tires. It is true, as you indicate in your letter, that the NHTSA prefers the use of the word "replaces," as opposed to "fits." This is because the former term is more specific in describing what both terms are intended to indicate, namely, that one tire size designation has superseded another. However, the NHTSA is of the opinion that the term "fits" may presently be used under Standard No. 109 in labeling the primary and alternative size designations, if the tire meets the dimensional and maximum load carrying capacities for both sizes. |
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.