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: aiam3475OpenMr. John Kime, Century Motor Coach, 59140 County Road 3 South, Elkhart, IN 46517; Mr. John Kime Century Motor Coach 59140 County Road 3 South Elkhart IN 46517; Dear Mr. Kime: This is to follow-up on your phone conversation of September 15, 1981 with Stephen Oesch of my staff concerning the agency's certification requirements for persons who alter certified vehicles. Your specific question was whether an alterer has to certify that the vehicle, as altered, is in compliance with all applicable safety standards affected by the alterations as of the date of the completion of the alterations or as of the date of the manufacture of the original vehicle. As explained below, an alterer may, at his or her option, choose either date.; The agency's certification regulations are set forth in Part 567 *Certification* (49 CFR Part 567), a copy of which is enclosed. Section 567.7 of the regulation applies to persons who alter certified vehicles. Section 567.7 specifies the content of the certification statement that must be affixed to the vehicle by the alterer. The portion of the regulation pertinent to your question is section 567.7(a) which provides that the alterer must state:; >>>'This vehicle was altered by (individual or corporate name) i (month and year in which alterations were completed) and as altered it conforms to all applicable Federal Motor Vehicle Safety Standards affected by the alterations and in effect in (month, year).' The second date shall be no earlier than the manufacturing date of the original vehicle, and no later than the date alterations were completed....<<<; Thus, the regulation allows an alterer the option of choosing eithe the date of original manufacture or the date of completion of the alterations as the date for determining which safety standards apply.; As you requested, I have also enclosed a copy of Standard No. 208 *Occupant Crash Protection*. Section 4.2.2 specifies the requirements applicable to trucks and multipurpose passenger vehicles with a gross vehicle weight rating of 10,000 pounds or less manufactured on or after January 1, 1976.; If you have any further questions, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1448OpenMr. M. Rein,Staff Engineer,Office of O. Weinreich,Director of Engineering,BMW of North America, Inc.,120 Pleasant Avenue,Upper Saddle River, New Jersey 07458; Mr. M. Rein Staff Engineer Office of O. Weinreich Director of Engineering BMW of North America Inc. 120 Pleasant Avenue Upper Saddle River New Jersey 07458; Dear Mr. Rein:#This responds to your March 19, 1974, request fo confirmation that the clamps and check valve that attach a vacuum hose assembly to a brake booster are not subject to Standard No. 106, *Brake hoses*.#A brake hose end fitting is defined as 'a coupler, other than a clamp, designed for attachment to the end of a brake hose.' As described by you, the couplers are the clamps and the check valve is an engine component to which the hose has been attached by the clamp couplers.Therefore your interpretation is correct that the clamps and check valve are not subject to Standard No. 106.#Yours truly,Richard B. Dyson,Assistant Chief Counsel; |
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ID: aiam3025OpenMr. Troy Martin, Chief of Specifications, State Board of Control, 111 East 17th Street, Austin, TX 78711; Mr. Troy Martin Chief of Specifications State Board of Control 111 East 17th Street Austin TX 78711; Dear Mr. Martin: This confirms your May 23, 1979, conversation with Roger Tilton of m staff in which you asked whether it is permissible for vehicles to be modified by the addition of propane gas systems replacing their regular fuel systems.; As Mr. Tilton stated, the National Highway Traffic Safet Administration permits the type of modification mentioned above. If the modification is done to a new vehicle, the person making the modification would be required to attach an alterer's label in accordance with Part 567.7, *Certification*, of our regulations. That label states that the vehicle, *as altered*, continues to comply with all safety standards. The standard that may be affected by such a modification would be Standard No. 301, *Fuel System Integrity*. If used vehicles are being modified, the person modifying the vehicle would not be required to attach a label. However, that person would be responsible for noncompliance with safety standards if he or she knowingly rendered inoperative any element of design installed in or on the vehicle in compliance with a safety standard.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1018OpenMr. W. S. Magenau, President, Chesapeake Marine Products, Route 456, Deale, MD 20751; Mr. W. S. Magenau President Chesapeake Marine Products Route 456 Deale MD 20751; Dear Mr. Magenau: This is in response to your letter of February 5, 1973, in which yo suggested, with reference to a previous interpretation, that boat trailer assemblers be allowed to use the 'altering distributor' certification of 49 CFR S 567.6, rather than certifying the vehicle as the manufacturer under S 567.4.; The altering distributor label was not designed to deal with assembler of vehicles, but with persons who alter vehicles that have already been completed and assembled. A basic prerequisite to its use is that there be a vehicle that already has been certified. I take it that your suggestion really amounts to requiring the supplier of the unassembled parts to certify the vehicle.; We are unwilling to do this on the basis of our present information. I is true that a boat trailer is among the simplest vehicles on the road, but considering vehicles generally, we must consider a vehicle as a functioning whole, not as a group of parts. There may easily be problems caused by the way in which it is assembled, and we do not consider it reasonable to require a manufacturer of parts, against his will, to take responsibility for the final assembly. Although it is conceivable that such a scheme could work with very simple vehicles, it certainly could cause large problems with more complex ones.; We permit the unassembled parts manufacturer to certify if he wishes Furthermore, the person who assembles the vehicle can require a written commercial warranty that the vehicle will conform if properly assembled, which will protect him in certifying the vehicle. I recommend one of these courses of action as a matter of good business practice.; If the unassembled parts manufacturer does certify the package i accordance with S 567.4(g)(1)(ii), then it would be permissible for a distributor to use S 567.6 where he deviates from the certifier's instructions.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0259OpenMr. Louis C. Lundstrom, Director, Automotive Safety Engineering, General Motors Engineering Staff, General Motors Technical Center, Warren, MI 48090; Mr. Louis C. Lundstrom Director Automotive Safety Engineering General Motors Engineering Staff General Motors Technical Center Warren MI 48090; Dear Mr. Lundstrom: This is in reply to your letter to Mr. Toms of October 15, 1970, i which you asked whether General Motors could provide one consumer information document to fleet purchasers of motor vehicles, rather than putting a booklet in each car as is done in the usual case.; The answer is yes. 49 CFR 575.6(a) requires that the information b provided 'to that purchaser', 'at the time a motor vehicle is delivered' to him. It does not require that the information be in the vehicle, or that there be one booklet per vehicle.; We are pleased to be of assistance. Sincerely, Rodolfo A. Diaz, Acting Associate Director, Motor Vehicl Programs; |
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ID: aiam2264OpenMr. G. E. Adams, Technical Manager, Dunlop Limited, Engineering Group, Holbrook Lane Coventry CV6 4AA, England; Mr. G. E. Adams Technical Manager Dunlop Limited Engineering Group Holbrook Lane Coventry CV6 4AA England; Dear Mr. Adams: This is in response to your letter of March 17, 1976, requestin information concerning steps which you, as a manufacturer of wheel equipment which will be offered for importation into the United States, must take in order to comply with all applicable National Highway Traffic Safety Administration regulations.; You should be aware of 49 CFR Part 566, *Manufacturer Identification* and 49 CFR Part 573, *Defect Reports*. In addition, Federal Motor Vehicle Safety Standard No. 119, *New Pneumatic Tires for Vehicles Other Than Passenger Cars*, may be of interest to you. Copies of these rules and an information sheet entitled 'Where to Obtain Federal Motor Vehicle Safety Standards and Regulations' are enclosed for your convenience.; Section 110(e) of the National Traffic and Motor Vehicle Safety Act (1 U.S.C. S 1399(e)) requires every manufacturer who offers a motor vehicle or item of motor vehicle equipment for importation into the United States as his agent, upon whom service of all processes, orders, notices, decisions, and requirements may be made.; The procedural regulations (49 CFR 551.45) for designation of agen pursuant to the Act require that it include:; >>>(1) A certification by its maker that the designation is binding o Dunlop Limited under the laws, corporate by-laws, or other requirements governing the making of the designation at the time and place where it is made,; (2) The full legal name, principal place of business and mailin address of Dunlop Limited,; (3) Trade names or other designations of origin of the products o Dunlop Limited that do not bear its legal name,; (4) A provision that the designation of agent remain in effect unti withdrawn or replaced by Dunlop Limited,; (5) A declaration of acceptance duly signed by the agent appointed which may be an individual, a firm, or a U.S. corporation, and; (6) The full legal name and address of the designated agent.<<< A copy of the procedural regulation for designation of agent i enclosed for your convenience.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam0609OpenMr. Richard F. Hirsch, 762 W. 30 Street, San Pedro, CA 90731; Mr. Richard F. Hirsch 762 W. 30 Street San Pedro CA 90731; Dear Mr. Hirsch: This is in reply to your letter of January 29, 1972, on the subject o test procedures under Standards 207 and 210.; Your questions deal with the general and frequently asked question o whether a manufacturer may devise his own test procedures to determine compliance with a standard. Our answer is that he is free to use whatever method he thinks appropriate to test his product, so long as his method reliably predicts the performance of the product when tested according to the procedures set out in the standard.; In answer to your first question, therefore, if testing of seats in mock up accurately indicates their performance in a vehicle, then mock up testing might be an appropriate test method. Our laboratories will be testing the seats in the vehicle. If a failure occurs, a manufacturer must show that he exercised due care in the development and production of the seat. To do this it will be necessary to show, among other things, that the development tests you conducted were, in fact, equivalent to the test procedures of the standard.; The same comment is appropriate in response to your second question. I you apply force through the seatbelt that approximates the combined forces of the belt anchorage test and seat anchorage test, you should take care to be sure that the test is, in fact, equivalent to a test in which the anchorages are tested simultaneously in the manner specified in Standards 207 and 210.; Your third question is whether the test must be conducted wit seatbelts and body locks, and if so, whether this would not be a redundant test of the seatbelt that is already required to conform to Standard 209. Although the response given to your first two questions is also appropriate for the third, there are practical reasons for using the vehicle's belts in the test. If the belt breaks, for example, it may be that your client would want to re-examine the sufficiency of the belt. Under Standard 208, the vehicle manufacturer is required to install a belt that conforms to Standard 209. If the belt fails in our testing under Standard 209, the vehicle manufacturer will have to show that he exercised due care in determining that the belt conformed to the standard. Using the belt in testing for Standard 210 is one way of detecting potentially serious belt problems.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2634OpenMr. Paul F. Bennett, Chief Engineer, Utility Trailer Manufacturing Co., P.O. Box 1299, City of Industry, California 91744; Mr. Paul F. Bennett Chief Engineer Utility Trailer Manufacturing Co. P.O. Box 1299 City of Industry California 91744; Dear Mr. Bennett: This responds to your May 20, 1977, letter asking whether your propose certification labels comply with the requirements of Part 567, *Certification*.; The National Highway Traffic Safety Administration (NHTSA) does no issue advance approval of compliance with Federal safety standards or regulations. We will, however, issue an opinion of whether your labels appear to comply with the regulations. The labels you submitted appear to comply with all but one of the requirements of Part 567 and Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. On your certification labels, you list the symbol 'W/' before the rim information. This symbol should be dropped from the label. Further the rim size designation should use the symbol 'x' between the diameter and width. Information supplied on a certification label must be provided in the form detailed in Part 567.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3926OpenMr. John L. Strickland, J.S. Welding, Rt. 5 Box 496, Denham Springs, LA 70726; Mr. John L. Strickland J.S. Welding Rt. 5 Box 496 Denham Springs LA 70726; Dear Mr. Strickland: I am responding to your February 20, 1985 request for informatio regarding Federal regulation of trailer manufacturing.; There is no Federal licensing requirement for the manufacture o trailers, which are considered motor vehicles under Federal law. As a manufacturer of a motor vehicle, however, you must submit identification information to the National Highway Traffic Safety Administration under 49 CFR Part 566, *Manufacturer Identification*. You must also certify that each trailer complies with all applicable Federal regulations. The procedure is specified in 49 CFR Part 567.; At this time, the only safety standards applicable to all trailers ar Safety Standard No. 108, *Lamps, reflective devices, and associated equipment*, Safety Standard No. 120, *Tire Selection and rims for motor vehicles other than passenger cars*, and Safety Standard No. 115, *Vehicle Identification Number-Basic Requirements*. The content requirements for the vehicle identification number are found at Part 565. Trailers with certain braking systems also must meet Safety Standard No. 106, *Brake hoses*, Safety Standard No. 116, *Motor vehicle brake fluids*, and Safety Standard No. 121, *Air brake systems*. These standards are found in Part 571 of 49 CFR.; I am enclosing an information sheet that explains how you can obtai copies of these regulations. If you have any further questions, please feel free to contact me.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam2321OpenMr. Donald L. Thompson, Managing Editor, NTDRA Dealer News, 1343 L Street, N.W., Washington, D.C. 20005; Mr. Donald L. Thompson Managing Editor NTDRA Dealer News 1343 L Street N.W. Washington D.C. 20005; Dear Mr. Thompson: I am writing to point out an error in an article that appeared in th May 24-31, 1976, issue of *NTDRA Dealer News* (Vol. XXXIX, No. 15). The article summarized a recent Federal Register notice (41 FR 18659, May 6, 1976, Docket No. 71-19, Notice 4) that delayed certain effective dates of Federal Motor Vehicle Safety Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars.*; The error appears in the paragraph of the article that reads: >>>Section 5.1.1 says that rims used must be those designated by th tire manufacturer. The effective date has been changed from March 1, 1977 to September 1, 1979.<<<; One requirement of S5.1.1 is that a vehicle be equipped with rims tha have been designated by the manufacturer of the vehicle's tires as suitable for use with those tires. The effective date of this requirements was originally established as September 1, 1976, and was not delayed be Notice4. Another requirement of S5.1.1 is that a vehicle be equipped with rims that comply with the standard, i.e., with rims that are marked according to S5.2, *Rim Marking.* Only the effective date of this vehicle requirement was changed from March 1, 1977, to September 1, 1979.; A clarification of these effective dates in a forthcoming issue o *NTDRA Dealer News* would be much appreciated.; Yours truly, Stephen P. Wood, Assistant Chief Counsel |
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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.