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: aiam0129OpenMr. G. Greig, Brixtax(London) Limited, Proctor Works Chertsey Road, Byfleet (Weybridge), Surrey, England; Mr. G. Greig Brixtax(London) Limited Proctor Works Chertsey Road Byfleet (Weybridge) Surrey England; Dear Mr. Greig: This is in reply to your letter of December 9, 1968, in which yo inquire about the certification responsibilities of equipment manufacturers under the National Traffic and Motor Vehicle Safety Act of 1966.; You state that it is your understanding that a vehicle manufacturer ha the responsibility to certify the entire vehicle, including equipment that is produced by other manufacturers and covered by Federal safety standards, as complying with the applicable standards, and that the basis on which that manufacturer satisfies himself that equipment from suppliers conforms to the standards is a matter of his own discretion. I consider that statement to be essentially correct, with the caveat that the manufacturer must be able to show, under S 108(b)(2) of the Act, that 'he did not have reason to know in the exercise of due care' that any included equipment was nonconforming. What constitutes 'due care' must be determined in light of all the circumstances of a particular case. You are also correct in your understanding that approval by the States has no relevance to the question of compliance with this Federal law.; Finally regardless of certification requirements all equipment mus conform to applicable standards, and certification by the equipment manufacturer is required if the equipment is ultimately sold in the aftermarket.; I am pleased to be of assistance. Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel for Regulations |
|
ID: aiam3345OpenMr. Bruce Henderson, Automobile Importers of America, Inc., 1735 Jefferson Davis Highway, Suite 1002, Arlington, Virginia 22202; Mr. Bruce Henderson Automobile Importers of America Inc. 1735 Jefferson Davis Highway Suite 1002 Arlington Virginia 22202; Dear Mr. Henderson: This responds to your September 4, 1980 letter to this office in whic you requested confirmation that a certain tire size was listed for use with a particular rim size in a tire publication recognized by this agency for purposes of Standard 110. Page 1-11 of the 1980 Yearbook of the Tire & Rim Association lists a 5 1/2 inch rim as appropriate for use with 185/70R14 tires. Thus, use of the 5 1/2 inch rims with that size tire would satisfy the requirements of paragraph S4.4.1(a) of Standard 110.; If you have any further questions or concerns regarding this matter feel free to contact Stephen Kratzke of my staff.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam2661OpenMr. Robert H. J. Loftus, McCandlish, Lillard, Bauknight, Church & Best, 4069 Chain Bridge Road, Fairfax, VA 22030; Mr. Robert H. J. Loftus McCandlish Lillard Bauknight Church & Best 4069 Chain Bridge Road Fairfax VA 22030; Dear Mr. Loftus: This responds to your August 4, 1977, letter asking whether th remanufacture of a school bus using a new chassis and an old school bus body constitutes the manufacture of a new school bus subject to the new Federal school bus safety standards.; The National Highway Traffic Safety Administration has determined tha the manufacture of a vehicle using a new chassis and an old body is the manufacture of a new vehicle. (Part 571.7, Title 49, Code of Federal Regulations.) In this regulation the agency indicated that the only time that the remanufacture of a vehicle would be exempted from compliance with the new safety standards is when an old chassis is combined with a new body. In those situations, the vehicle is considered a used vehicle not subject to the standards.; In the case to which you refer, the combination of a new chassis and a old school bus body would require that you modify the bus body to comply with all of the Federal school bus safety standards in effect on the date of your manufacture of the new bus.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
|
ID: aiam1606OpenMr. Norman E. Salzman, General Manager, The Fairmount Press, P.O. Box 3, Bronx, NY 10453; Mr. Norman E. Salzman General Manager The Fairmount Press P.O. Box 3 Bronx NY 10453; Dear Mr. Salzman: This is in response to your letter of August 19, 1974, inquiring as t the compliance of your MVF odometer disclosure form with the Federal odometer requirements.; The MVF form enclosed in your letter fails to comply with ou regulation in several respects. The statement referring to the mileage indicated on the odometer at the time of the vehicle's transfer must be phrased to indicate that the disclosure document was executed at the time of the vehicle's transfer, not at some later time. In addition, the statement must be written in such a manner that it is clear it is to be completed by the transferor alone. To satisfy these criteria the statement should read; >>>'I, * *, state that the odometer mileage indicated on the vehicl described above, at the time of transfer to * * is as follows:'<<<; Instructions are necessary on your form to ensure that the sectio specified for the disclosure of mileage is completed in a consistent manner by all persons. This can be accomplished by inserting the following statement above the lines provided for stating the vehicle's mileage:; >>>'(Complete line 1, and where applicable, complete line 2 and chec line 3.)'<<<; We urge you to reprint your disclosure forms to reflect the change suggested above as they are not currently in compliance with Federal odometer requirements.; Your interest is appreciated. Yours truly, Richard B. Dyson, Acting Chief Counsel |
|
ID: aiam0745OpenMr. Stan Haransky, Associate Director, Truck Body and Equipment Association, Inc., 5530 Wisconsin Avenue, Suite 1120, Washington, DC 20015; Mr. Stan Haransky Associate Director Truck Body and Equipment Association Inc. 5530 Wisconsin Avenue Suite 1120 Washington DC 20015; Dear Mr. Haransky: This is in reply to your letter of May 30, 1972, forwarding to u correspondence you received from Mr. Calvin D. Kunkle of FMC Corporation. Mr. Kunkle's question, as explained in a telephone conversation we had with him on June 16, 1972, is whether building vehicles whose actual loaded weight exceeds the gross vehicle weight rating of the chassis violates Federal law. Mr. Kunkle stated that he believed certain manufacturers of fire-fighting vehicles were presently doing that.; If the loaded weight is clearly inconsistent with the definitions o GVWR and GAWR as specified in 49 CFR 571.3, the manufacturer will be in violation of the Certification regulations, (49 CFR Part 567) and may be subject to civil penalties. Also, if the loaded weight of the completed vehicle or the weight imposed on any of its axle systems exceeds the stated ratings, the vehicle might be found by NHTSA to contain a safety-related defect. In such a case, the manufacturer is required to mail notification of the defect to all the purchasers. In addressing whether such a safety defect exists, the NHTSA considers the situation as a whole, including such factors as the manufacturer's ratings, and the true capacity of the vehicle.; We advised Mr. Kunkle during our conversation that if he will furnis to NHTSA the names of companies he suspects are involved in this practice, we will take action to bring them into conformity with the requirements.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam3075OpenMr. Robert J. Crail, Director of Engineering, The Berg Manufacturing Company, P.O. Box 368, Iola, KS 66749; Mr. Robert J. Crail Director of Engineering The Berg Manufacturing Company P.O. Box 368 Iola KS 66749; Dear Mr. Crail: This responds to your June 28, 1979, letter asking several question about the compliance of your trailers with Standard No. 121, *Air Brake Systems*.; You first ask whether section S5.6.3 allows the use of service air t apply the parking brakes as long as a source of energy to apply the parking brakes is available at all times and is unaffected by any single failure in the service brake system. The answer to this question is yes. On August 9, 1979, the agency published in the Federal Register a notice amending section S5.6.3 of the standard to permit the type of parking brake system that you outlined in your letter.; In your second question, you ask whether your braking system complie with section S5.2.1.1. That section requires that a reservoir be provided that is capable of releasing the vehicle's parking brakes and that is unaffected by the loss of pressure in the service brake system. Your trailer has a tank and valve for each axle. You state that in the event of a service system failure including a failure of one of the tanks, that a reservoir is available such that when the supply line is pressurized to 55 psi, the vehicle's parking brakes will release. Assuming that your system operates as you have detailed in your letter, the agency concludes that it complies with S5.2.1.1 of the standard.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam1865OpenMr. A.F. Bleiweiss, P.Eng., Vice President, Dominion Auto, Accessories Limited, 420 Keele Street, Toronto 9, Canada; Mr. A.F. Bleiweiss P.Eng. Vice President Dominion Auto Accessories Limited 420 Keele Street Toronto 9 Canada; Dear Mr. Bleiweiss: This is in response to your letter of March 29, 1975, inquiring as t the permissibility of selling your 'Panamirror' in the United States as aftermarket equipment.; Motor Vehicle Safety Standard No. 111, *Rearview Mirrors*, Provide minimum performance requirements for rearview mirrors on passenger cars and multipurpose passenger vehicles. According to the standard, the inside rearview mirror must furnish the driver with a specified field of view to the rear of substantially unit magnification. Any vehicle manufactured for sale, sold, or introduced into interstate commerce must be equipped with an inside rearview mirror that meets the designated level of performance. It appears that the 'Panamirror' would not satisfy the requirements of the provision, because it is convex in structure and therefore would not provide a view of substantially unit magnification.; If the mirror were installed on a vehicle as aftermarket equipmen (after the vehicle's first purchase for purposes other than resale) in such a way as to render inoperative the inside rearview mirror, section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (Pub. L. 89-563) as amended (Pub. L. 93-492) would apply where the installation was accomplished by a manufacturer, distributer, dealer, or motor vehicle repair business. The section prohibits the named parties from knowingly rendering inoperative a system installed in compliance with an applicable motor vehicle safety standard.; Yours truly, James C. Schultz, Chief Counsel |
|
ID: aiam3561OpenMr. J. F. Walkup, Project Analyst, Research & Development Center, Reeves Brothers, Inc., Post Office Box 26596, Charlotte, NC 28213; Mr. J. F. Walkup Project Analyst Research & Development Center Reeves Brothers Inc. Post Office Box 26596 Charlotte NC 28213; Dear Mr. Walkup: This responds to your April 6, 1982, letter asking whether the agency' standard No. 302, *Flammability of Interior Materials*, applies to after-market equipment. The answer to your question is no.; Standard No. 302 is a vehicle standard and as such applies to complete vehicles. No vehicle can be manufactured unless the materials used in it comply with the requirements of the standard. The standard does not apply, however, to items of equipment in the after market. You should be aware that while you would not be prohibited from manufacturing after-market equipment that does not comply with the standard, a manufacturer, repair business or dealer would be prohibited from installing such noncomplying equipment if the installation would have the effect of rendering inoperative the compliance of the vehicle with the safety standard. Nothing prevents a vehicle owner, however, from installing noncomplying equipment in his own vehicle.; I trust that this responds to your question. Please contact me if I ca be of further assistance.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam0611OpenMr. K. Krueger, Technical Development, Liaison Engineer, Volkswagen of America, Inc., Englewood Cliffs, NJ, 07632; Mr. K. Krueger Technical Development Liaison Engineer Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Krueger: This is in reply to your letter of December 6, 1971, in which you as several questions regarding the test procedures of Standard No. 302, 'Flammability of Interior Materials,' and list certain components asking whether they are subject to the standard. While we indicated to you in our letter of February 17, 1972, that we are considering amendments to the standard which affect the questions you raise, we are responding, because of the limited time remaining before the standard becomes effective, to your questions based on the standard as presently written, indicating where appropriate, those areas where modifications may be made.; The three questions you raise regarding the test procedures of th standard are restated in part below, followed by our response.; >>>1. How is a part whose largest dimension is less than one inch an which is subject to the requirements of S4.1 to be tested under S5? You state that many small parts of Volkswagens would fall through the wire grid if required to be tested.; If a component fits the criteria of S4.1, it is required to meet th standard's requirements regardless of its size. In testing, however, manufacturers are not required to follow the procedures set forth in the standard, but may modify those procedures as long as results obtained can be correlated sufficiently that the manufacturer can show he exercised due care in attempting to meet the requirements. In the case of components that are too small to be supported by the wire grids, we believe manufacturers would be free to space the wire grids so that, at the very least, the component can be supported, and still avail themselves of a due care defense. One other alternative, although not as easily correlated to the standard, would be to test samples of the material of which the component is manufactured in sizes large enough to be supported by the test device as described in the standard.; 1(a). If the specimen held in the frame offers less than 1.5 inches o material from its open end to its clamped end, does it have to be tested under MVSS 302?; The answer to this question is similar to the one above. There is n exemption for small components in the standard. However, minor modifications to the test procedure may be made without jeopardizing the ability of a manufacturer to demonstrate, should the need arise, that he has exercised due care. In this case, we believe that a manufacturer could begin timing before the flame had traveled 1.5 inches, or again, could test larger samples of the material of which the component is made.; 1.(b). If a small specimen held in the frame offers less than 2 inche of material for progression of the flame after timing has begun, and if the material stops burning before it has burned for 60 seconds from the start of timing, does it meet the requirements of S4.3?; The provisions of S4.3 that you refer to are intended to reflect th performance of samples described in the test procedures of S5. These requirements are intended to provide an exemption for self-extinguishing materials, and not to exempt small samples that are consumed by fire before two minutes elapse. The standard establishes burn-rate requirements, and manufacturers should keep this in mind in determining whether particular components comply. If your component is such that it is consumed by fire because of its size before the two-minute period, then we would expect modifications to the procedure, of a nature described above, to be made in order that a determination of the burn rate of the material is obtained.; 2. 'We do not understand the applicability requirements of S4.1 specifically the latter part of the paragraph which states, ' . . ., and any other interior materials, including padding and crash-deployed elements, that are designed to absorb energy on contact by occupants in the event of a crash.'' You then list certain components and ask whether they fall within the quoted language.; This provision is presently under review by NHTSA, and may be modifie in the amendment to be published in the near future. Any such change may also affect the problems you appear to have in testing very small components, as indicated by your previous questions. However, as presently written, the phrase refers to those components which are in fact designed to be energy absorbing. This determination must be made by the manufacturer, based upon the design of his vehicles. It does not appear to us that any of the components you list would necessarily fall within the quoted language.; The list you provide includes numerous gaskets, or gasket-typ components such as (a) windshield gasket, (b) side door insulating rubber, (c) door gaskets, (h) rubber boots at base of gear shift and hand brake levers, (l) gaskets for sliding sun roof, and (m) gasket between steering column and firewall. If these items are not within the above-quoted language of S4.1, we would not consider them to be covered by any other language of that paragraph.; With reference to the open truck compartments in Type 2, Type 3, an Type 411 vehicles (your paragraph (d)), we consider areas in passenger vehicles where occupants can ride, such as the rear of station wagons, to be within the occupant compartment, and the components listed in S4.1 that appear in these areas must meet the requirements.; With reference to paragraph (e), we would consider the battery cover if it is part of the floor, to be a floor covering within S4.1 However, we do not consider electric cables (f) to be within any of the enumerated items of S4.1. In addition, the brake fluid reservoir (g) would only be included if it is within the 'any other interior materials . . .' language of S4.1.<<<; Sincerely, Lawrence R. Schneider, Chief Counsel |
|
ID: aiam0825OpenMr. Steven M. Sharp, Managing Director, Intercontinental Equipment Corp., 5383 Overland Avenue, San Diego, CA 92123; Mr. Steven M. Sharp Managing Director Intercontinental Equipment Corp. 5383 Overland Avenue San Diego CA 92123; Dear Mr. Sharp: This is in response to your letter of July 27, 1972, in which you rais several questions concerning Part 566, Manufacturer Identification, Part 567, Certification, and Part 568, Vehicles Manufactured in Two or More Stages. You state that Intercontinental Equipment Corp. (I.E.C.) is the United States importer and distributer of certain vehicles manufactured by Suzuki Motor Co., Ltd. in Japan. You also state that I.E.C. has contracted with Yachiyoda Sangyo Co., Ltd. of Tokyo to acquire vehicles from Suzuki, remove non-complying equipment, install approved devices, and affix necessary labels of conformity and arrange for shipment.; The answers to your questions are as follows 1. You ask whether the I.E.C. contract with Yachiyoda changes th status of Suzuki as manufacturer and I.E.C. as importer. It does not change the status with respect to our manufacturer identification and certification regulations.; 2. You inquire as to the classification of Suzuki and Yachiyoda unde Part 568, Vehicles Manufactured in Two or More Stages. Since Suzuki manufactures a completed vehicle, Yachiyoda is not considered a manufacturer under NHTSA regulations and is not required by the NHTSA to submit manufacturer identification or certification information.; 3. You ask whether the label of conformity (Label 2) which you propose to have affixed to the vehicles is acceptable. Th NHTSA finds it acceptable.; I enclose copies of Parts 566, 567, and 568 for your information. Sincerely, Richard B. Dyson, Assistant 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.