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: aiam0330OpenDavid A. Phelps, Jr., Group Supervisor, Engineering Services, Blue Bird Body Company, Fort Valley, GA 31030; David A. Phelps Jr. Group Supervisor Engineering Services Blue Bird Body Company Fort Valley GA 31030; Dear Mr. Phelps: This is in reply to your letter of April 22, 1971, to Mr. Carte concerning section 574.10 of Part 574 - Tire Identification and Record Keeping, as it applies to tires on a chassis for which you sell and mount the body.; In cases where the chassis are manufactured and sold with tires by th chassis manufacturer or chassis dealer, it would be permissible for the manufacturer of the chassis to maintain the record of tires on the chassis, and the name of the user of the chassis, and notify the user in the event a defect notification is required.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam0118OpenMr. Max Walter, Citroen Cars Corporation, 415-421 Third Avenue, Brooklyn, NY 11215; Mr. Max Walter Citroen Cars Corporation 415-421 Third Avenue Brooklyn NY 11215; Dear Mr. Walter: By your letter of October 8, 1968 you ask if the glazing material i the rear window of passenger cars can be 4 millimeters thick and be in compliance with Federal Motor Vehicle Standard No. 205, Glazing Materials - Passenger Cars, Multipurpose Passenger Vehicles, Motorcycles, Trucks, and Buses.; Standard No. 205 requires that glazing materials conform to the AS Standard Z26.1-1966. The ASA standard Z26.1- 1966 does not set forth how thick glazing material must be but requires the glass used to meet certain tests, depending on the type of vehicle the glass is being used in and the location of the glass in that vehicle.; Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel for Regulations |
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ID: aiam0689OpenMrs. Janet P. Lannan, Office Manager, Coirtex, 4535 North Ravenswood Avenue, Chicago, IL, 60640; Mrs. Janet P. Lannan Office Manager Coirtex 4535 North Ravenswood Avenue Chicago IL 60640; Dear Mrs. Lannan: This is in reply to your letter of April 19, 1972, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials' to 'coco fibre' floor mats which you supply to distributors who resell them to dealers for optional placement in cars.; Standard No. 302 does not apply to floor coverings that are no provided with the vehicle by its manufacturer. Consequently, aftermarket floor mats are not subject to its requirements.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2712OpenDirector, Office of Standards Enforcement; Director Office of Standards Enforcement; I have received your November 8, 1977, memorandum questioning th applicability of the performance requirements in Section S5.4 of Standard No. 217 to knock-out rear windows. You suggest that these requirements may apply only to push-out windows, not knock- out windows.; It is our interpretation that the requirements of the standard apply t both push-out and knock-out windows. We realize that this may create some difficulty for purposes of conducting compliance testing since knock-out windows must be reinstalled in order to conduct subsequent tests upon them. Nonetheless, the window should be required to comply with the standard.; Joseph J. Levin, Jr. |
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ID: aiam2208OpenMr. J. Trimble, Secretary General, European Tyre and Rim Technical Organisation, Avenue Brugmann, 32 Bte 2, 1060 Bruxelles, Belgium; Mr. J. Trimble Secretary General European Tyre and Rim Technical Organisation Avenue Brugmann 32 Bte 2 1060 Bruxelles Belgium; Dear Mr. Trimble: This is in response to your letter of January 26, 1976, which inquire about the status of the E.T.R.T.O. petition for an amendment of Federal Motor Vehicle Safety Standard No. 119, *New Pneumatic Tires for Vehicles Other Than Passenger Cars*, concerning tires for low-power motorcycles with restricted speed capability.; We expect to issue a Federal Register notice on this subject in th near future.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3309OpenMr. Bart Achille, National Sales Manager, American Moped Associates, 1852 Langley Avenue, Irvine, California 92714; Mr. Bart Achille National Sales Manager American Moped Associates 1852 Langley Avenue Irvine California 92714; Dear Mr. Achille: This is in reply to your letter of June 11, 1980, asking whether push-in type supplement engine stop switch is permissible under Federal Motor Vehicle Safety Standard No. 123, *Motorcycle Controls and Displays*.; Table 1 of Standard No. 123 does not specify the method of operation o the supplement engine stop control and, as you correctly guessed, your planned switch is therefore not prohibited. In accordance with the standard, however, it must be located on the right handlebar.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3439OpenMr. Carol Fitzjohn, Quality Control Manager, C.J.B. Industries, Inc.,P. O. Box 779, Chanute, Kansas 66720; Mr. Carol Fitzjohn Quality Control Manager C.J.B. Industries Inc. P. O. Box 779 Chanute Kansas 66720; Dear Mr. Fitzjohn: This responds to your June 2, 1981, letter asking about th requirements for reservoir tanks for air brake systems. In particular, you ask whether section S5.1.2.2 and S5.2.1.3 are the only Federal requirements applicable to the manufacture of the reservoirs.; The two sections that you referenced in your letter are the onl sections specifying requirements for the construction of reservoirs for air brake systems. For additional guidance in the construction of reservoir, you should refer to SAE standard J10b titled 'Automotive and Off Highway Air Brake Reservoir Performance and Identification Requirements.' This standard will provide you with the prevailing industry practice in the construction of reservoirs.; You should be aware that you would be responsible under the Nationa Traffic and Motor Vehicle Safety Act if there were any defect relating to motor vehicle safety in your product.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0268OpenCharles O. Verrill, Jr., Esq., Messrs. Patton, Blow, Verrill, Brand & Boggs, 1200 17th Street, N.W., Washington, DC 20036; Charles O. Verrill Jr. Esq. Messrs. Patton Blow Verrill Brand & Boggs 1200 17th Street N.W. Washington DC 20036; Dear Mr. Verrill: In your letter of November 16 you inquire whether the Bureau' interpretation of 'overall width' (49 CFR S 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 wides 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.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam1398OpenMr. Thomas S. Pieratt, Jr., Executive Secretary, Truck Equipment & Body Distributors Assoc., 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Jr. Executive Secretary Truck Equipment & Body Distributors Assoc. 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in response to your letter of January 30, 1974, requestin information concerning whether or not a certification label is required to be furnished by one who installs a snow plow on a completed vehicle prior to the first purchase of the vehicle for purposes other than resale.; An additional certification label is required when a vehicle is altere by the addition of parts that are not readily attachable components. Whether or not the snow plow is a readily attachable item depends in large part on the manufacturer's intent in designing the vehicle.; If the addition of the snow plow necessitated a change in the weigh ratings of the vehicle, there would be an obligation of the alterer's part to attach an additional certification label in accordance with 49 CFR 567.7.; Thank you for your inquiry. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2185OpenMr. Roger R. King, King Company Inc., 4308 Stewart Avenue, Wausau, WI 54401; Mr. Roger R. King King Company Inc. 4308 Stewart Avenue Wausau WI 54401; Dear Mr. King: This is in response to your letter of November 19, 1975, concernin tire registration numbers, and in confirmation of your telephone conversation with Mr. Schwartz of this office.; Thank you for your suggestion that the tire identification numbe appear on both sidewalls of tires which are delivered already mounted on a vehicle. It is being reviewed by our technical staff, and we will advise you by letter of our decision in this matter.; In answer to your question concerning the types of vehicles covered b the term 'motor vehicle,' 'motor vehicle' is defined in the National Traffic and Motor Vehicle Safety Act of 1966 as 'any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails.'; Yours truly, 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.