
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: nht71-2.9OpenDATE: 02/18/71 FROM: AUTHOR UNAVAILABLE; Rodolfo A. Diaz; NHTSA TO: Bandag Incorporated TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter to Mr. Hartman concerning the tire identification and record keeping regulation (49 CFR Part 574) requesting that you be allowed to code by pressure chamber rather than by matrix. Since the pressure chamber is used by Bandag to serve a purpose similar to the purpose served by the matrix in hot processing of retreaded tires, you may assign(Illegible Word) numbers to your pressure chambers and use this code number in place of the matrix code number required by Part 574. |
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ID: nht71-3.1OpenDATE: 05/14/71 FROM: AUTHOR UNAVAILABLE; Douglas W. Toms; NHTSA TO: Mrs. Barbara G. Rothschild TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of April 28, 1971, in which you asked whether modifications to a "forced-action" belt could make it into a system that would satisfy the passive restraint requirements of Standard No. 208. Although we cannot at this time comment on the changes to which you refer, a passive belt system can be used to satisfy the requirement that protection be provided by means that require no action by vehicle occupants. As you requested, we have enclosed copies of the Standard as published March 10, 1971. |
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ID: nht71-3.10OpenDATE: 05/27/71 FROM: AUTHOR UNAVAILABLE; R. L. Carter; NHTSA TO: Ideal Corporation TITLE: FMVSS INTERPRETATION TEXT: In your letter of May 4, 1971, to Francis Armstrong you request permission to conduct testing of turn signal and hazard warning signal flashers pursuant to SAE Standard J823b, "Flasher Test Equipment," April 1963. Federal Motor Vehicle Safety Standard No. 108 incorporates by reference SAE Standard J590b, "Automotive Turn Signal Flashers," October 1965, and SAE Recommended Practice J945, "Vehicular Hazard Warning Signal Flasher," February 1966, both of which specify test circuitry and equipment according to "SAE J823." It is my understanding that the major difference between J823 and J823b, which becomes the appropriate sub-referenced standard on January 1, 1972, is the specification in the latter that "The required voltage tests [for variable-load flashers] with maximum bulb load shall be conducted without readjusting each corresponding power supply voltage, previously set with minimum bulb load." It appears that J823 was written before variable load flashers were in general use and that this is the reason for omission of this specification from J823. Since J823b includes all the requirements of the presently referenced SAE standard, you may proceed to implement it immediately. |
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ID: nht71-3.11OpenDATE: 06/01/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: The General Tire & Rubber Company TITLE: FMVSR INTERPRETATION TEXT: This is in response to your letter of May 17, 1971, concerning the applicability of the Tire Identification and Record keeping Regulation (49 C.F.R. 574) to trailers as expressed in our letter of March 18, 1971, to Mr. Charles O. Verrill. As you mentional in your letter, under the regulation, a vehicle dealer has the responsibilities of a tire dealer if he adds or changes the tires on a vehicle he sells. This was considered appropriate because the manufacturer has little, if any, control over which tires go on which vehicles if the tires are shipped separately. In such a case, the vehicle dealer will be mounting the tires and therefore it is logical that he record the name and address of the first purchaser along with the identification number of the tires mounted on the vehicle and forward this information to the tire manufacturer. The Tire Identification and Record Keeping Regulation and the Certification Regulation for Vehicles Manufactured in Two or More Stages are two completely different regulatory matters. The factors which dictate the related responsibilities of the incomplete vehicle manufacturer and the final-stage manufacturer for purposes of certification are not necessarily relevant to the tire identification regulations. |
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ID: nht71-3.12OpenDATE: 06/02/71 FROM: L. R. SCHNEIDER -- NHTSA; SIGNATURE BY DAVID SCHMELTZER TO: Truck Trailer Manufacturers Association TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of May 28, 1972, requesting clarification of whether a vehicle manufacturer, under 574.10 of the Tire Identification and Record Keeping regulation, may designate someone to maintain the records for his. This letter is to confirm that motor vehicle manufacturers may assign a designee for the record keeping requirements of Part 574. |
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ID: nht71-3.13OpenDATE: 06/02/71 FROM: L. R. SCHNEIDER -- NHTSA; SIGNATURE BY DAVID SCHMELTZER TO: Long Mile Rubber Company TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter to Mr. Van Orden dated May 20, 1971. Tires retreaded prior to the effective date of the retread standard (January 1, 1972) are not permitted to contain the DOT symbol on the tire. If you have marked your matrices with the symbol, I suggest you buff the letters off the tire after it is retreaded, or remove the symbol from the matrix, or fill in that portion of the matrix. The retreading of tires without the DOT markings before the effective date of the standard is permissible. |
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ID: nht71-3.14OpenDATE: 06/02/71 FROM: L. R. SCHNEIDER -- ACTING CHIEF COUNSEL, NHTSA; SIGNATURE BY RICHARD B. DYSON TO: Recreational Vehicle Institute Inc. TITLE: FMVSR INTERPRETATION TEXT: This is in response to your letter of May 18, 1971, with which you enclosed eleven questions that time precluded answering at the recent Recreational Vehicle Institute symposium. Some of the questions are really comments or expressions of opinion, and the answer must be of the same nature. 1. Where does the manufacturer's responsibility start and end, and where does the sub-contractor's or supplier's responsibility start and end? This question must obviously be answered in general terms. The primary thrust of the National Traffic and Motor Vehicle Safety Act is the regulation of manufacturers. Under the statutory scheme set up by Congress and the standards and regulations that we have issued, the "manufacturer" is viewed as the final producer of a particular product -- either a completed vehicle or a defined type of motor vehicle equipment. Although we recognize that in virtually all types of manufacturing there is actually a multiple chain of production from basic raw materials to final product, it is necessary for our purposes to fix legal responsibility on the final "assembler"; our legal system offers ample ways in which the final manufacturer can and does share some of the responsibility with his suppliers, primarily through the system of contracts and warranties that is basic to all commercial activities. Thus, where a standard is concerned, we look to the final manufacturer for compliance purposes. His responsibilities are, of course, modified by the possibility of a due care defense, whether or not supplied products are involved. There are some exceptions: for example, the Vehicles Manufactured in Two or More Stages regulation creates some limited responsibilities on the manufacturers of "incomplete vehicles"; and the responsibility for safety-related defects extends to all manufacturers of motor vehicle equipment, whether or not covered by a standard. 2. Are RV manufacturers required to provide more proof of compliance than the compliance nameplate. There is no requirement that manufacturers "provide proof of compliance", beyond the certification label, as a routine matter (the sense in which the question was probably intended). If the NHTSA discovers evidence of noncompliance with the standards, by testing or otherwise, it normally asks the manufacturer to provide the test results or other information or data that formed the basis for his certification that the product conformed to the particular standard in question. This is a normal function of the administrative process whereby the agency gathers all available information in the course of deciding whether and how to proceed in an enforcement action. Obviously, it is in the manufacturer's interest to maintain carefully the records of testing and other data upon which he bases his certification. 3. Are defect reports required relative to plumbing or electrical defects which are functional defects but could in some cases have safety implications? Who makes the decision concerning the safety implication? Defect reports and appropriate notification action are required in the case of any defects determined to be safety-related. These would include defects in the plumbing or electrical systems, as in any other system of the vehicle. Section 113 of the Act requires the vehicle manufacturer to make this determination and take appropriate action on his own initiative. The NHTSA also has the authority to make an independent determination on the question, under procedures that afford the manufacturer the opportunity to present his own evidence. 4. Is there a statutory requirement that rulings and standards in fact be reasonable, and in fact reduce some known hazard? If so, how do you establish the fact that a particular hazard is real, does exist and the proposed standards will reduce such hazards? The act requires that a standard "shall be practicable, shall meet the need for motor vehicle safety, and shall be stated in objective terms," and also that it be "reasonable, practicable and appropriate for the particular type of motor vehicle or item of motor vehicle equipment for which it is prescribed." The NHTSA devotes a great deal of effort to establishing that hazards are "real", and that a standard "will reduce such hazard". The effort is multifaceted, and includes analysis of known accident data, existing research data, research studies and tests funded and managed by NHTSA, information gathered from industry and other sources, and the knowledge and expertise of NHTSA technical personnel. 5. What will be the NHTSA's view in regard to a motor home that exceeds the chassis manufacturer's GVWR? Under the new certification regulations scheduled to come into effect January 1, 1972, the final-stage manufacturer will have the responsibility for establishing the GVWR of his vehicle, and there are no inherent restrictions on the value that he establishes. It is anticipated that the standards will base many of the performance requirements on the GVWR and GAWR of the vehicle, and it may often be to the final-stage manufacturer's advantage to remain within the incomplete vehicle manufacturer's recommended values in order to take full advantage of the protections provided by the regulation on Vehicles Manufacturered in Two or More Stages. 6. Mr. Wood's talk mentioned that "some trailers" might be included in the definition of passenger motor vehicle" in S. 976, the "Hart Bill". What trailers are "some trailers"? Our opinion on the meaning of terms in bills before Congress can only be speculative, and the terms in question may be changed if and when the bill is enacted, or clarified by the legislative history. "Motor vehicles" under the present National Traffic and Motor Vehicle Safety Act clearly include trailers. We are not sure whether or not the reference in the definition ("any motor vehicle manufactured primarily for the transportation of its operator and passengers upon the public streets, roads, and highways") to "its operator" is intended to exclude trailers. 7. Do you think that the NHTSA should use "due care" before proposing a standard to be reasonably certain that there exists correlation between a small-scale test and realistic tests -- which are preferably large scale? The answer to question 4, includes the statutory criteria under which the NHTSA operates in issuing standards and regulations. The validity of test procedures is one of the basic issues that must be taken into account by the NHTSA in the issuance of any regulation. 8. When a proposal or rule is issued, have the test procedures been proven by the government? If not, how can "doubted" results be correlated by the NHTSA test facilities? How do you compare results as related to test equipment? In terms of the broad generalities of the question and the scope of this letter, little more can be said in addition to the answers to question 4 and 7. The agency must make every reasonable effort to assure that the standards meet the statutory criteria, and are the best way of dealing with the safety problems involved. 9. What are the present tie down angle(Illegible Word) for seat belts and are there any exceptions? The requirements for seat belt installations are contained in the published standards, and we request that persons concerned with requirements such as those mentioned first examine the standards as they relate to his particular case. We will be pleased to answer questions related to specific requirements of the standards, either by letter or in person. 10. It would seem that the standards and due care testing lead to a concentration of the industry into a few major companies. Is NHTSA concerned about this effect and is it willing to see it happen in order to accomplish NHTSA's goal? The economic impact of the standards is one of the main concerns of the NHTSA in its rulemaking activity; it is part of the determination of "practicability" required by the Act. Mr. Toms devoted a major part of his address at the banquet (after the question was asked) to this problem, and his remarks probably contain the most complete discussion on the subject that we can offer. 11. Which, if any, of the speakers has had personal experience vacationing in a recreational vehicle? The speakers, and other personnel of the NHTSA, have the responsibility to discharge their functions as objectively and fairly as possible, unbiased by their "personal experiences", vacationing or otherwise. We hope and intend that the motor vehicle safety program will, to the greatest extent possible, enable the public to have safe and enjoyable vacation experiences with your members' products. |
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ID: nht71-3.15OpenDATE: 06/08/71 FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA TO: Mercedes-Benz of North America, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your May 21, 1971, letter to Mr. H. H. Wallace to determine whether Dunlop is in compliance as to the use of spaces in the tire identification number. There are no objections to the spaces between the different parts of the number. However, the photograph illustrates other problem, that of a dual size marked tire. Dual size marked tires are not permissible. The tire can be labeled as one size tire with the indication that it replaces another size tire. For example, 205R14 replaces ER70-14. The General Secretary of ETRTO has been advised of the "dual marked" tire usage. |
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ID: nht71-3.16OpenDATE: 06/08/71 FROM: L. R. SCHNEIDER -- ACTING CHIEF COUNSEL, NHTSA; SIGNATURE BY DAVID SCHMELTZER TO: Blue Bird Body Company TITLE: FMVSR INTERPRETATION TEXT: This letter is to further clarify an interpretation contained in our letter of Nov. 6, 1971, concerning the Tire Identification and Record Keeping Regulation. We wish to make it clear that although the final-stage manufacturer may designate someone to maintain the records required under section 574.10 of the Tire Identification and Record Keeping Regulation, the legal responsibility for maintaining the records remains with the final-stage manufacturer. However, the incomplete vehicle manufacturer, or any intermediate vehicle manufacturer, may assume "legal responsibility for all duties and liabilities imposed on manufacturers by (the Act) with respect to the vehicle as finally manufactured . . ." (49 C.F.R. 568.7). In such a case, the responsibilities for maintaining the records required by the Act and the Tire Identification and Record Keeping Regulation will be assumed by the incomplete vehicle manufacturer, or any intermediate manufacturer, and the final-stage manufacturer will be relieved of all liability for maintaining the records. We would also point out that the Tire Identification and Record Keeping Regulation was not meant to preclude the use of multiple designees for the maintenance of the required records. See the enclosed interpretation issued on May 28, 1971 (36 F.C. 9780). |
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ID: nht71-3.17OpenDATE: 06/08/71 FROM: L. R. SCHNEIDER -- ACTING CHIEF COUNSEL, NHTSA; SIGNATURE BY DAVID SCHMELTZER TO: British Leyland Motors Inc. TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of May 20, 1970, requesting an interpretation of the Tire Identification and Record Keeping Regulation (49 C.F.R. 574). The proposals you described in your letter, paragraphs 1 and 2, will certainly meet the minimum requirements of the regulation and are perfectly acceptable. The regulation requires that a record be kept of the type of tire shipped on or in the vehicle. It does not require that the individual tire identification number be(Illegible Word) with the name and address of the purchaser. If a vehicle dealer sells a vehicle equipped with tires which were not shipped on or in the vehicle, the vehicle dealer is considered a tire dealer under section 574.9(b) and as such, he is required to record the name and address of the first purchaser along with the tire identification number, and forward this information to the tire manufacturer. However, the tire manufacturer may designate someone else to maintain the required records by section 574.7. Therefore, it would be acceptable to have your vehicle dealers forward the required information to you instead of to the tire manufacturer, if the tire manufacturer designates you to maintain the records of tires installed on your vehicles. If we can be of any further assistance, please feel free to write. |
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.