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: nht69-1.3OpenDATE: 06/02/69 FROM: AUTHOR UNAVAILABLE; Robert Brenner; NHTSA TO: Hon. Jacob K. Javita -- U.S. Senate COPYEE: Mr. Delve; Mr. O'Mahoney TITLE: FMVSS INTERPRETATION TEXT: This is in further reply to your transmittal memorandum and attached letter from Mr. Robert W. Muller, New York, New York, inquiring about consumer information on passenger car tires. The Department of Transportation does not presently have a publication which would guide the consumer in selecting tires most suitable to his needs. To provide the consumer with an indication of the performance characteristics of tires, the Federal Highway Administration is obtaining research data and has established Docket 25, Uniform Tire Quality Grading System - Passenger Cars. A copy of the notice from the Federal Register is enclosed. As soon as a meaningful system of tire quality grading can be developed to assist the public, it will be made available. Enclosure |
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ID: nht69-1.49OpenDATE: 04/10/69 FROM: AUTHOR UNAVAILABLE; Charles A. Baker; NHTSA TO: Department of California Highway Patrol TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of January 24, 1969, to Dr. William Haddon, Jr., former Director, National Highway Safety Bureau, concerning the installation of front identification lamps on various vehicles manufactured in more than one stage. Motor Vehicle Safety Standard No. 108 specifies that multipurpose passenger vehicles, trucks, truck tractors, and buses of 80 inches or more in overall width shall be equipped with three identification lamps on the front of the completed vehicle. This standard is applicable to the completed vehicle and it is the responsibility of the final assembler to certify that such vehicle conforms to the standard. A manufacturer of a chassis-cab is not required to mount identification lamps on the chassis-cab. However, if he does so, the manufacturer who adds a body to the chassis-cab is not required to add identification lamps to the front of the body. |
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ID: nht69-1.9OpenDATE: 02/01/69 EST FROM: AUTHOR UNAVAILABLE; Charles A. Baker; NHTSA TO: Hucck and Company TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of February 11, 1969, to Mr. David A. Fay, concerning your request for an interpretation on Standard No. 108. Subsection (d) of Section 103 of the National Traffic and Motor Vehicle Safety Act of 1966 states "Whenever a Federal Motor vehicle safety standard established under this title is in effect, no State or political subdivision of a State shall have any authority either to establish, or to continue in effect with respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the name aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard . . ." Since Federal Motor Vehicle Safety Standard No. 108 is now in effect, and permits red or amber rear turn signal lamps, the States cannot restrict these lamps to be red only. |
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ID: nht69-2.20OpenDATE: 11/24/69 FROM: R. H. COMPTON -- DIR., OFC. OF STANDARDS ON ACCIDENT AVOIDANCE, MVS PS, NHTSA; SIGNATURE BY C. A. BAKER TO: Gumifabriken Gislaved Aktiebolag TITLE: FMVSS INTERPRETATION TEXT: In response to your letter of November 3, 1969, the Department of Transportation hereby assigns number 210 to the Gumifabriken Gislaved Aktiebolag, Gislaved, Sweden, as its approved code mark. The approved code mark is for use in identifying the tire manufacturer in accordance with S4.3 of Federal Motor Vehicle Safety Standard No. 109 and the National Traffic and Motor Vehicle Safety Act of 1966 (15 USC 1421 (1)). Your attention is directed to the requirement for designation of an agent in accordance with the National Traffic and Motor Vehicle Safety Act of 1966, Subsection (110(e)). This requirement is implemented by our "General Procedural Rules, Subpart D - Service of Process; Agents. As requested, I have enclosed a copy of the Federal Motor Vehicle Safety Standards No. 109 and No. 110 with amendments. |
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ID: nht69-2.4OpenDATE: 02/12/69 FROM: AUTHOR UNAVAILABLE; Charles A. Baker; NHTSA TO: Scientific Brake & Equipment Company TITLE: FMVSS INTERPRETATION TEXT: Your letter of November 11, 1968, to Mr. Barkley Sweet, Truck Body and Equipment Association, concerning lighting for trucks equipped with snow plow blades, has been hand-carried by him to this Bureau for consideration and reply. Federal Motor Vehicle Safety Standard No. 108 requires that all trucks be equipped with headlamps mounted at a height above the road surface not more than 54 inches. To effectively illuminate the road when its snow plow is in use, a truck often runt be equipped with additional headlamps at a height greater than 54 inches, and you are correct in installing these lights for dealers and purchasers. With respect to the several specific questions listed on page 2 of your letter, I would point out that local and State regulations should be reviewed for possible requirements relating to the additional lamps used on trucks operating as snow-plowing vehicles. |
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ID: nht70-1.12OpenDATE: 10/29/70 FROM: AUTHOR UNAVAILABLE; R. H. Compton; NHTSA TO: Atlas Supply Company TITLE: FMVSS INTERPRETATION TEXT: Reference is made to your letter of October 8, 1970, requesting an increase in the maximum permissable overall width of the "78" series belted bias passenger car tires covered by Table I-J, Appendix A, of MVSS 109. The dimensional requirements specified in MVSS 109 for passenger car tires are the result of a rule making action in which the tire industry and other interested persons participated. Tire section width and overall width were permitted to exceed the specified section width dimensions by 7% to accommodate differences in manufacturing tolerances, design practice, tire growth patterns when inflated, and to provide for sidewall decorations and protective ribs. The allowance of 7% is considered the maximum desirable for dimensional uniformity and interchangeability among tires of the same size produced by different manufacturers. For this reason, we cannot give favourable consideration to your request at this time. |
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ID: nht70-1.16OpenDATE: 08/01/70 EST FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Transelex Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of August 5 discussing your "new type of warning beacon' for use on emergency vehicles. The photometric test action of SAE Recommended Practice J845,(Illegible Words) Emergency Warning Lamp refers to both "lamps flashed by rotation or oscillation" and lamps flashed by current interruption". The letter phrase appears to cover the Transelex lamp as you have described it, and we interpret J845 as applicable. Our interpretation would seem to answer your question on AAMVA approval. Current Federal lighting requirements do not cover warning lamps, and even if they did, no Department of Transportation approval would be required. Under the National Traffic and Motor Vehicle Safety Act of 1966 it is the manufacturer of motor vehicles or equipment to which a standard applies who certifies compliance with that standard. Sincerely, |
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ID: nht70-2.2OpenDATE: 04/09/70 FROM: AUTHOR UNAVAILABLE; R. A. Diaz; NHTSA TO: Toyo Kogyo Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of March 2, 1979, to Mr. Clue D. Ferguson, concerning an interpretation of Federal Motor Vehicle Safety Standard No. 111. In your letter you indicated that the mirror, as mounted in the vehicle, cannot be hit at a 45 degrees angle by a 6.5 inch head form because of the geometric arrangement in your automobile. In this case we would accept the maximum(Illegible Words) Form. We must point out, however, that the test also includes any other angle from the one you describe down to a 45 degrees angle under this horizontal(Illegible Word) S3.1.2.3 of standard No. 111). Please note that this interpretation is intended to provide(Illegible Line)(Illegible Line)(Illegible Words) a given item of equipment meets applicable Federal motor vehicle safety standards and he must certify to that effect. |
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ID: nht68-1.42OpenDATE: 05/28/68 FROM: AUTHOR UNAVAILABLE; J. R. O'Gorman; NHTSA TO: Minnesota Automotive, Inc. TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of April 1, 1968, to the Motor Vehicle Safety Performance Service, concerning compliance with the Federal Motor Vehicle Safety Standard No. 105. Basically, when a car dealer modifies a conforming vehicle, he then assumes responsibility for the vehicle's compliance to all applicable standards if that vehicle is distributed to a purchaser for purposes other than resale. Specifically, if a car dealer installs the Model 7900 Driver Training Brake on a conforming vehicle that he sells, than compliance to the Federal Motor Vehicle Safety Standard No. 105, as well as other applicable standards, is required. In the case where the dealer owns and loans the vehicle with the installed Model 7900, we would hope that he would again comply. The enclosed literature may be of additional assistance to you in response to your inquiry. |
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ID: nht68-2.11OpenDATE: 05/27/68 FROM: AUTHOR UNAVAILABLE; David A. Fay; NHTSA TO: FWD Corporation TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of January 11, 1968, Dr. William Haddon, Jr., concerning the location of headlamps on vehicles which are used for snow plow service. I regret that a clerical error resulted in this late reply to your inquiry. Snow plows are motor vehicles and subject to regulatory actions as established by the National Traffic and Motor Vehicle Safety Act of 1966. Motor Vehicle Safety Standard No. 108 requires that vehicles to which the standard is applicable be equipped with headlamps that are located not less than 24 inches nor more than 54 inches above the road surface (see Table II of the standard). This requirement does not prohibit the use of additions) headlamps located at greater heights as illustrated by the photographs enclosed with your referenced letter. Thank you for writing. |
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.