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: aiam0095OpenMr. Warren M. Heath, Commander, Engineering Section, Department of California Highway Patrol, P.O. Box 898, Sacramento, CA 95804; Mr. Warren M. Heath Commander Engineering Section Department of California Highway Patrol P.O. Box 898 Sacramento CA 95804; Dear Mr. Heath: Thank you for your letter of July 1, 1968, to Mr. George C. Nield concerning a clarification of paragraph S 3.4.3 of Federal Motor Vehicle Safety Standard No. 108.; Paragraph S 3.4.3 specifies that, as a minimum, the taillamps shall b illuminated when the headlamps are illuminated, except when the headlamps are being flashed. The phrase 'except when the headlamps are being flashed', permits the vehicle manufacturer to use a separate switch or flasher for illuminating the headlamps only when it would not be appropriate or in the interest of safety to simultaneously illuminate the taillamps and headlamps. In addition to the examples cited in your letter, such devices could also be used for flashing the headlamps on public transit vehicles to indicate an emergency situation.; Since the subject matter of S 3.4.3 is taillamps and since Federa Standard No. 108 is otherwise silent as to headlamp flashing, this matter appears to be within the purview of the California vehicle code.; Thank you for your continued interest in the motor vehicle safet standards.; Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam4620OpenMs. Gay M. Arthur 20096 Park Hill Dr. Barrington, IL 60010; Ms. Gay M. Arthur 20096 Park Hill Dr. Barrington IL 60010; Dear Ms Arthur: This is in reply to your letter to Taylor Vinson o this Office. You have asked if 'detachable, lighted novelty items are legally allowable on passenger cars,' specifically 'for the exterior roof.' You appear to have in mind an item of aftermarket equipment, that is to say, an item which is not original equipment on a car, but one that the vehicle owner purchases during the course of his ownership. There is no restriction under Federal law as to roof-mounted novelty items if they are installed by the vehicle owner. If they are installed by a manufacturer, distributor, dealer, or motor vehicle repair business, they are permissible as long as they do not render inoperative, in whole or in part, equipment that is installed pursuant to a Federal motor vehicle safety standard. For example, if installation of the novelty light affected the wiring and hence the performance of lighting equipment installed on the vehicle by its manufacturer, that would be a 'rendering inoperative' within the meaning of the prohibition. Use of the novelty light would be determined by the laws of a State in which it is operated. We are unable to advise you on State laws, and suggest that, for further information, you consult the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, VA 22203. Sincerely, Stephen P. Wood Acting Chief Counsel; |
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ID: aiam0440OpenMr. J. Wuddel, Ing., Westfalische Metall Industrie KG, Hueck & Co., 4780 Lippstadt, Postfach 604, West Germany; Mr. J. Wuddel Ing. Westfalische Metall Industrie KG Hueck & Co. 4780 Lippstadt Postfach 604 West Germany; Dear Mr. Wuddel: This is in reply to your letter of August 20, 1970, concerning Moto Vehicle Safety Standard No. 302 (Docket 3-3, Notice 4) 'Flammability of Interior Materials.' You ask whether 'plastic materials such as those covering control lamps, for the control lamps themselves, for the control knobs and for the interior lights must also meet the same requirements.' The components you list are not specifically enumerated in S4.1 of the standard, and are not required to meet the standard's burn- rate requirements unless they are 'any other interior materials. . . that are designed to absorb energy on contact by occupants in the event of a crash.' (See the last sentence of S4.1, copy enclosed) This will depend on the particular configuration of the vehicle in question, and the manufacturer must determine, based on the design of his vehicle, whether the components you describe fall within the quoted language.; In answer to your second question, the NHTSA neither requires no provides prior approvals for motor vehicles or motor vehicle components. Questions concerning these approvals should be directed to the jurisdiction, such as the State of California, which you mention, that is involved.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam5583OpenMr. Douglas Helbig Vice President Spencer Testing Services P.O. Box 429 Spencer, WV 25276; Mr. Douglas Helbig Vice President Spencer Testing Services P.O. Box 429 Spencer WV 25276; Dear Mr. Helbig: It has come to my attention that Spencer Testin Services is advertising its inspection procedure as 'NHTSA approved.' This representation is incorrect. NHTSA has not approved this or any other inspection procedure. Therefore, I must insist that this language be immediately removed from the advertisement and that you refrain from making such representations in any other format. Please send me a copy of the corrected advertisement without reference to the inspection procedure being NHTSA approved. Thank you for your immediate attention to this matter. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam1315OpenHonorable Jack Edwards, House of Representatives, Washington, DC 20515; Honorable Jack Edwards House of Representatives Washington DC 20515; Dear Mr. Edwards: Your request for information on the Federal Odometer Disclosur regulation on behalf of Mr. Charles J. Fleming has been referred to me for reply.; I am enclosing a copy of the regulation which includes an example of a acceptable format. Other formats are acceptable if all the required information is included.; We are unable to advise Mr. Fleming about the effect of a particula typographical error without knowing its nature, but as a general matter a typographical error would not give rise to liability unless it were deceptive in a way which misleads a purchaser.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3683OpenMr. Richard H. Attenhofer, Technical Manager, O.E., Dunlop Tire Company, Box 1109, Buffalo, NY 14240; Mr. Richard H. Attenhofer Technical Manager O.E. Dunlop Tire Company Box 1109 Buffalo NY 14240; Dear Attenhofer: This responds to your recent letter to Mr. Kratzke of my staff requesting an interpretation of 49 CFR Part 574, *Tire Identification and Recordkeeping*. Specifically, you asked if Dunlop could use a print type called OCR-A for the DOT symbol and the tire identification number.; Note 1 to Figure 1 of Part 574 specifies only four different prin types which may be used for the DOT symbol and identification number, none of which are OCR-A. However, Note 4 to Figure 1 states that other print type will be permitted if approved by this agency. We have examined the print type shown in the diagram attached to your letter and have no objections to your company printing the required information in OCR-A type.; In the final rule establishing Part 574 (35 FR 17257, November 10 1970), the agency explained that the reason for specifying only four print types which would be acceptable without advance agency approval was to ensure that the information would be easily readable by all persons. The OCR-A print type shown in the diagram attached to your letter is easily readable and thus satisfies our concerns in that regard. Accordingly, that print type is hereby approved.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3682OpenMr. Richard H. Attenhofer, Technical Manager, O.E., Dunlop Tire Company, Box 1109, Buffalo, NY 14240; Mr. Richard H. Attenhofer Technical Manager O.E. Dunlop Tire Company Box 1109 Buffalo NY 14240; Dear Attenhofer: This responds to your recent letter to Mr. Kratzke of my staff requesting an interpretation of 49 CFR Part 574, *Tire Identification and Recordkeeping*. Specifically, you asked if Dunlop could use a print type called OCR-A for the DOT symbol and the tire identification number.; Note 1 to Figure 1 of Part 574 specifies only four different prin types which may be used for the DOT symbol and identification number, none of which are OCR-A. However, Note 4 to Figure 1 states that other print type will be permitted if approved by this agency. We have examined the print type shown in the diagram attached to your letter and have no objections to your company printing the required information in OCR-A type.; In the final rule establishing Part 574 (35 FR 17257, November 10 1970), the agency explained that the reason for specifying only four print types which would be acceptable without advance agency approval was to ensure that the information would be easily readable by all persons. The OCR-A print type shown in the diagram attached to your letter is easily readable and thus satisfies our concerns in that regard. Accordingly, that print type is hereby approved.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1293OpenL.E. Haight, Esq., Attorney at Law, 805 Idaho Street, P.O. Box 2777, Boise, ID 83701; L.E. Haight Esq. Attorney at Law 805 Idaho Street P.O. Box 2777 Boise ID 83701; Dear Mr. Haight: This is in reply to your letter of September 21, 1973, concerning you desire to disconnect the interlock system on your new car.; The dealer who sold you the car was required to have the interloc working at the time of sale, pursuant to section 108(a)(1) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(1)). However, section 108(b)(1) of the Act (15 U.S.C. 1397(b)(1)), provides that the requirements of 108(a)(1) do not apply after the first purchase of the vehicle for purposes other than resale. As a purchaser who intends to use the vehicle, you are therefore not subject to the requirements of the Act and may disconnect the interlock.; Despite the absence of legal sanctions for disconnecting the interlock we would hope that you could find a way to adjust the belt so that it could be worn without aggravating your bursitis. The physical sanctions for an unbelted person in a crash can be serious indeed.; Sincerely, Richard B. Dyson |
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ID: aiam0854OpenMr. E. M. Anderson, Vice President, Ingram Manufacturing Co., P.O. Box 2020, San Antonio, TX 78297; Mr. E. M. Anderson Vice President Ingram Manufacturing Co. P.O. Box 2020 San Antonio TX 78297; Dear Mr. Anderson: I apologize for the delay in answering your letter regarding Part 566 Manufacturer Identification. You describe the vehicles you manufacture and ask whether you are a manufacturer within the meaning of the regulation and therefore required to submit information regarding your products.; Part 566 applies to manufacturers of motor vehicles and motor vehicl equipment to which a motor vehicle safety standard applies. 'Motor vehicle' is defined in the National Traffic and Motor Vehicle Safety Act as 'any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highway'. Since the portable tandem rollers you describe appear to be manufactured for construction or farm use you are not considered a manufacturer of motor vehicles and are not covered by Part 566. Therefore you are not required to submit information under that regulation. For similar reasons you are not covered by the certification requirements of Part 567 and 568 which you also mentioned.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0855OpenMr. E. M. Anderson, Vice President, Ingram Manufacturing Co., P.O. Box 2020, San Antonio, TX 78297; Mr. E. M. Anderson Vice President Ingram Manufacturing Co. P.O. Box 2020 San Antonio TX 78297; Dear Mr. Anderson: I apologize for the delay in answering your letter regarding Part 566 Manufacturer Identification. You describe the vehicles you manufacture and ask whether you are a manufacturer within the meaning of the regulation and therefore required to submit information regarding your products.; Part 566 applies to manufacturers of motor vehicles and motor vehicl equipment to which a motor vehicle safety standard applies. 'Motor vehicle' is defined in the National Traffic and Motor Vehicle Safety Act as 'any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highway'. Since the portable tandem rollers you describe appear to be manufactured for construction or farm use you are not considered a manufacturer of motor vehicles and are not covered by Part 566. Therefore you are not required to submit information under that regulation. For similar reasons you are not covered by the certification requirements of Part 567 and 568 which you also mentioned.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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.