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: aiam0628OpenG. E. Masters, General Manager, U. M. Electrical Distributors Ltd., UMED, Beaumont Road, Banbury, Oxon, ENGLAND; G. E. Masters General Manager U. M. Electrical Distributors Ltd. UMED Beaumont Road Banbury Oxon ENGLAND; Dear Mr. Masters: This is in response to your letter of March 6, 1972, concerning warnin buzzers for the automobile industry.; The National Highway Traffic Safety Administration has issued tw safety standards which specify warning requirements. These requirements are given in Paragraph S4.4 of Standard 114 and Paragraph S7.3.1 of Standard 208. A copy of these two standards are enclosed for your review and further information.; You will note that these standards do not stipulate minimu requirements for the warning devices, and, at the present time, we have no plans to specify such requirements. The data sheet, however, which you enclosed will be useful to us should we specify such requirements in future amendments to these standards.; We appreciate your writing to us, and if we can be of any furthe service, please let us know.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam4897OpenMrs. Debby Funk R.R. #1, Box 41A Shirley, IL 61772; Mrs. Debby Funk R.R. #1 Box 41A Shirley IL 61772; Dear Mrs. Funk: This responds to your letter of July 5, l99l, as followup to my letter of June 25. You have asked whether 'it would be illegal for the owner of a vehicle that has a center highmounted stop lamp to install an additional rear window brake light? (anywhere in the back window?)' The answer is that it would not be illegal under Federal law for a vehicle owner to install an additional stop lamp anywhere in the back window, providing that all modifications were performed by the owner. However, the legality of the modification would still be subject to State law. You have also asked 'What is F.M.V.S.S. 108?' That is Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment. It can be found in Title 49 Code of Federal Regulations, as Section 571.108. If you have further questions, please don't hesitate to write. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam0508OpenMr. Vic Trahd, Import-Export, 7308 Hinds Avenue, #4, North Hollywood, CA, 91605; Mr. Vic Trahd Import-Export 7308 Hinds Avenue #4 North Hollywood CA 91605; Dear Mr. Trahd: This is in replay to your letter of November 20, 1971, to Mr. Frankly 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 us of it is, however, subject to the regulations of the individual States.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam1688OpenMr. Bob Nottingham, Silver Eagle Manufacturing Company, 10505 N.E. 2nd Ave., Portland, OR 97211; Mr. Bob Nottingham Silver Eagle Manufacturing Company 10505 N.E. 2nd Ave. Portland OR 97211; Dear Mr. Nottingham: This responds to your November 8, 1974, question whether permanently-attached steerable axle on a trailer is required to meet the parking brake requirements for trailer converter dollies or those for all other vehicles.; In answer to your question, the permanently-attached steerable axle yo describe is not a separate vehicle which would qualify as a trailer converter dolly. Therefore the axle is simply part of a trailer which must meet the parking brake requirements of either S5.6.1 or S5.6.2. Neither of these options specifies that there be parking brakes on steerable axles, although in satisfaction of S5.6.2 (grade holding), the manufacturer could utilize parking brakes on the steerable axle.; I would like to add that, although S5.8 does not presently specif emergency braking capability for steerable axles on trailers, we intend to issue a proposal in the near future to require such performance on these axles. Your redesign plans may wish to take this upcoming proposal into consideration.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam2909OpenMr. Brian Gill, American Honda Motor Co., Inc., P.O. Box 50, Gardena, California 90247; Mr. Brian Gill American Honda Motor Co. Inc. P.O. Box 50 Gardena California 90247; Dear Mr. Gill: This is in response to your letters of October 9, 1978, and October 20 1978, concerning Federal Motor Vehicle Safety Standard No. 115, *Vehicle identification number*.; Since the agency was considering petition for reconsideration when you letter was received, we concluded that it would be more helpful to respond to your letter after the revised standard was issued. A copy of a notice of the amendments to the standard and a copy of a notice of proposed rulemaking to further amend the standard are enclosed.; The type face shown in the attachment to your letter of October 9 1978, meets the requirements of S4.3.1. Since the standard does not specify a location for the placement of the VIN on motorcycles, it may be stamped on the certification label. However, Honda should also consider stamping the VIN on the cycle frame as well, to aid in recovery if the motorcycle is stolen.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2445OpenMr. David Edmonson, Chief Engineer, HM Vehicles, 6276 Greenleaf Tr., Apple Valley, MN 55124; Mr. David Edmonson Chief Engineer HM Vehicles 6276 Greenleaf Tr. Apple Valley MN 55124; Dear Mr. Edmonson: This is in reply to your letter of October 15, 1976, to Secretar Coleman asking for copies of our regulations that would apply to a small vehicle, apparently three-wheeled, which you intend to manufacture in limited numbers.; I enclose a copy of an information sheet that tells where you ma obtain copies of the Federal motor vehicle safety standards that apply to motor vehicles, and of the regulations that apply to manufacturers. I also enclose a copy of the National Traffic and Motor Vehicle Safety Act of 1966, the authority for the safety standards and regulations. If you have any questions after reviewing these materials, I will be happy to answer them for you.; Three-wheeled vehicles are classified, and will be for the foreseeabl future, as 'motorcycles.' A proposed redefinition which would have removed enclosed three-wheeled vehicles from the definition is in abeyance and consideration is being given, as you suggested, to establishing standards appropriate for all lightweight motor vehicles.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam1286OpenMr. Jordan J. Pokrinchak, President, Jordan Research Corporation, 179 Rennell Driver, Southport, CT 06490; Mr. Jordan J. Pokrinchak President Jordan Research Corporation 179 Rennell Driver Southport CT 06490; Dear Mr. Pokrinchak: This is in reply to your letter of September 18, 1973 asking for a interpretation of Standard No. 108. You understand that 'the stop lamps must light when applying the automobile brakes and/or when applying the trailer brakes individually.' You tell us of a product that gives a driver 'manual control of the trailer brakes [but] does not light the stop lamps in this mode.'; Paragraph S4.5.4 of Standard No. 108 requires that 'the stop lamps o each vehicle shall be activated upon application of the service brakes.' This section of Standard No. 108 requires that stop lamps on new motor vehicles be wired in this manner. The standard does not apply after the vehicle is purchased, and thus does not prohibit a vehicle owner from modifying the wiring of his vehicle by adding the Electronic Trailer Brake Control. Such an addition, however, might be precluded under State law.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2096OpenJ.W. Boyd, Manager, Government & Industry Technical Relations, Dunlop Tire and Rubber Corporation, Box 1109, Buffalo, NY 14240; J.W. Boyd Manager Government & Industry Technical Relations Dunlop Tire and Rubber Corporation Box 1109 Buffalo NY 14240; Dear Mr. Boyd: Thank you for your letter of July 8, 1975, to Ed Wallace of our Tir Division, enclosing a letter from Mr. W. Preuss of Dunlop Germany, concerning the allocation, between vehicle manufacturers and tire manufacturers, of responsibility for the safety of original equipment tires.; Section 159 of the National Traffic and Motor Vehicle Safety Act o 1966, as amended by the Motor Vehicle and Schoolbus Safety Amendments of 1974, specifies that, except as otherwise provided in regulations of this agency, a defect in or noncompliance of an original equipment tire shall be the responsibility of the vehicle manufacturer. The NHTSA has recently granted the petitions of the Motor Vehicle Manufacturers Association, General Motors, and the European Tyre and Rim Technical Organisation for a reallocation of this responsibility. We expect to issue a notice of proposed rulemaking on this subject in the near future.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1995OpenMr. James E. Johnson, Chief Engineer, Construction Machinery Company, P.O. Box 120, Waterloo, IA 50704; Mr. James E. Johnson Chief Engineer Construction Machinery Company P.O. Box 120 Waterloo IA 50704; Dear Mr Johnson: This responds to your June 18, 1975, question whether a system whic pressurizes a water tank on a concrete mixer by means of air from the truck's air brake system would violate the requirements of Standard No. 121, *Air brake systems*.; The answer to your question is no. Standard No. 121 does not contain prohibition on the use of air pressure from the air brake system for powering auxiliary devices. The vehicle must of course conform to Standard No. 121 following installation of the device if the installation occurs prior to the first purchase in good faith for purposes other than resale.; Although not a requirement of the standard, the National Highwa Traffic Safety Administration does consider it appropriate that a pressure protection valve be placed in the line to the auxiliary device so that a rupture of an auxiliary line does not cause depletion of air pressure in the brake system.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2018OpenMr. Robert J. Ostrander, Dana Corporation, Tech. Center, 8000 Yankee Road, Ottawa Lake, MI 49267; Mr. Robert J. Ostrander Dana Corporation Tech. Center 8000 Yankee Road Ottawa Lake MI 49267; Dear Mr. Ostrander: This responds to Dana Corporation's July 11, 1975, question whether system which controls a truck engine throttle from a remote location by means of compressed air from the truck's brake system would violate the requirements of Standard No. 121, *Air brake systems*.; The answer to your question is no. Standard No. 121 does not contain prohibition on the use of air pressure from the air brake system for powering auxiliary devices. The vehicle must of course conform to Standard No. 121 following installation of the device, if the installation occurs prior to the first purchase in good faith for purposes other than resale. For example, the compressor build-up pressure would still be required to meet S5.1 of the standard.; Although not a requirement of the standard, the NHTSA does consider i appropriate that a pressure protective valve be placed in the line to the auxiliary device so that a rupture of an auxiliary line does not cause depletion of air pressure in the brake system.; Sincerely, Frank Berndt, Acting 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.