
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: nht78-1.35OpenDATE: 05/11/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Dr. Arthur Yeager TITLE: FMVSS INTERPRETATION TEXT: This responds to your telephone request of March 24, 1978, asking whether the seats in school buses are sufficiently strong to allow the installation of seat belts. You stated that some manufacturers are indicating that they cannot install seat belts because the floors of larger school buses cannot withstand the forces generated by seat belts. As you indicated, Notice 5 of Docket 73-3 stated that school bus seats should be strong enough to withstand the forces seat belts would impose upon them. This statement was based upon the fact that the seats would be designed to comply with the other force requirements of the standard which would increase the strength of the seats making them capable of withstanding seat belt loads. At the time of that notice, there were special seat belt requirements for seat belts in school buses in the then proposed Standard No. 222. These seat belt requirements would have mandated lower belt load requirements than those found in Standard No. 210 which currently applies to school buses (under 10,000 pounds GVWR). The seats in larger school buses should be sufficiently strong to withstand the former proposed force requirements of Standard No. 222, but they might be incapable of withstanding the belt load requirements of Standard No. 210. Manufacturers who indicate that the seats or floors of larger buses are not strong enough to install seat belts probably misunderstood the belt requirements for large buses. Seat belts can be installed for passenger seats in larger school buses without complying with any existing seat belt requirements. Seat belts for passenger seats are not required, for example, to comply with Standard No. 210. Therefore, a State would be permitted to establish their own acceptable belt load requirements for these seat belts in large school buses. The National Highway Traffic Safety Administration suggests that States adopt the belt load requirements previously proposed for Standard No. 222. School bus seats currently in production should be sufficiently strong to withstand the former proposed belt load requirements. |
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ID: nht78-1.36OpenDATE: 05/11/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Blue Bird Body Company TITLE: FMVSS INTERPRETATION TEXT: This responds to your February 9, 1978, letter asking how to measure the head form contact area in Standard No. 222, School Bus Passenger Seating and Crash Protection. In your first paragraph, you indicate that the National Highway Traffic Safety Administration (NHTSA) has allowed the knee form contact area measurement to be undertaken on or within a line 1 1/2 inches from the edge of the leg protection zone to ensure that the knee form will contact the entire surface. You ask that a similar line be established for the head protection zone contact areas. As you know, the head form contact area requirements apply to more areas than do the knee form contact area requirements. The knee form contact area requirements apply only to seat backs and the backs of restraining barriers. The head form contact area, on the other hand, includes anything falling within a specified zone which might include the sides or tops of seats. Therefore, it is impossible to create fictional lines around the outer edges of objects that fall within the head protection zone for purposes of testing the compliance of those objects with the requirements. The agency notes further that it never stated that it would test knee form contact area on or inside a line 1 1/2 inches from the edge of a seat back or restraining barrier. The agency did state that it would test in a manner that "provides opportunity for the knee form to contact with the seat back or restraining barrier to the fullest extent possible." That interpretation can also be applied to the head form contact area requirements. SINCERELY, BLUE BIRD BODY COMPANY February 9, 1978 Joseph J. Levin Chief Counsel National Highway Traffic Safety Administration Dear Mr. Levin: Reference: 1. W. G. Milby to Frank Berndt, December 20, 1976 2. Frank Berndt to W. G. Milby, February 23, 1977, N 40-30 Reference number 1 requests an interpretation that the centerline of the knee impact tests of FMVSS 222 only be required on or inside of a line 1 1/2" (same as knee form radius) from the edge of the leg protection zone. The reason for the request was to insure that it is physically possible to obtain the required contact area and to insure that enough padding of the correct composition is available for the knee form to contact. Reference number 2 grants the request of reference number 1. The purpose of this letter is to confirm our assumption that the same reasoning should be applicable to the head protection zone. Thank you for your early response. W. G. Milby Manager, Engineering Services |
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ID: nht78-1.37OpenDATE: 01/26/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Sheller-Globe Corporation TITLE: FMVSS INTERPRETATION TEXT: This responds to your December 6, 1977, letter asking which portions of the roof and sidewall structure of your small bus must comply with the head impact requirements of Standard No. 222, School Bus Passenger Seating and Crash Protection. In accordance with the head impact zone requirements outlined in paragraph S5.3.1.1 of the standard, the National Highway Traffic Safety Administration has determined that those portions of your bus constituting the bus sidewall and window structure are not required to comply with the head impact requirements. Only those portions of your bus which constitute part of the roof structure are included within the head impact zone requirements. We have marked in yellow on the enclosed drawing those areas that must comply with the head impact requirements. SINCERELY, SHELLER-GLOBE CORPORATION Vehicle Planning and Development Center December 6, 1977 National Highway Traffic Safety Administration Attention: Chief Counsel, Frank A. Berndt Gentlemen: Reference is made to S.5.3.1.1. of FMVSS 222 - School Bus Seating and Crash Protection, which states the bus sidewall, window, or door structure are not included in the impact zone. Our question is, what all do you consider as window structure and if a side body pillar and the structure over the top of the window assembly to which the window is mounted, are also not included in the impact zone? The pillar and structure in question are marked in red for the Dodge and blue for a Chevrolet on drawing #K-4300021. It would be appreciated if you would indicate on the extra copy of the drawing area needing or not needing to be included in the impact zone. R. M. Premo - Director Vehicle Safety Activities |
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ID: nht78-1.38OpenDATE: 04/25/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Wayne Corporation TITLE: FMVSS INTERPRETATION TEXT: This responds to your February 28, 1978, letter asking whether portions of your van-type school bus have to comply with the head protection zone requirements of Standard No. 222, School Bus Passenger Seating and Crash Protection. You enclosed pictures showing portions of the bus designated in pink and yellow and question the standard's applicability to them. The head protection zone requirements do not apply to portions of the school bus that are considered part of the bus sidewall. The National Highway Traffic Safety Administration considers the sidewall to include those surfaces that run parallel to the outboard edge of a forward facing seat. Accordingly, the portions of your bus designated in yellow in the pictures need not comply with the requirements since they are part of the bus sidewall structure. The pink portions of your photographs represent part of the bus structure that is perpendicular to the bus sidewall. The NHTSA does not consider them to be part of the bus sidewall structure. Therefore, since they fall within the head protection zone they must comply with all of the requirements applicable to that zone. Sincerely, ATTACH. PHOTO A VIEW LOOKING FORWARD TOWARD RIGHT-HAND FRONT SERVICE DOOR. (Graphics omitted) PHOTO B VIEW LOOKING FORWARD TOWARD LEFT-HAND FRONT DRIVER'S AREA. (Graphics omitted) Wayne Corporation February 28, 1978 Office of Chief Counsel National Highway Traffic Safety Administration Dear Sir: This inquiry concerns Federal Motor Vehicle Safety Standard 222, School Bus Passenger Seating and Crash Protection. The enclosed photographs marked and labeled as follows: Photo A - View looking forward toward right-hand front service door, and Photo B - View looking forward toward left-hand front driver's area, show interior views of the Wayne Busette school bus described in the enclosed Wayne Busette specification sheet. The interior surfaces of the bus colored pink and yellow in Photos A and B fall within the head protection zone defined in FMVSS 222, S5.3.1.1. For purposes of clarity, the front row of passenger seats had been removed before the pictures were taken. Please advise whether or not the areas colored pink and yellow in Photos A and B are subject to the requirements of FMVSS 222, S5.3.1.2, Head Form Impact Requirements, and S.5.3.1.3, Head Form Force Distribution. In responding to this inquiry, we ask that consideration be given to the first paragraph of S5.3.1.1, "The head protection zones in each vehicle are the spaces in front of each school bus passenger seat which are not occupied by bus sidewall, window, or door structure and which . . . ." Wayne believes that while the pink and yellow colored areas are located in front of a passenger seat, these surfaces should be classified as part of the bus sidewall, window, and door structure and, therefore, are excluded from the requirements of S5.3.1.2 and S5.3.1.3. Your prompt attention and early reply to this inquiry would be greatly appreciated. Sincerely yours, Robert B. Kurre Director of Engineering [Enclosures Omitted] |
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ID: nht78-1.39OpenDATE: 06/16/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Blue Bird Body Company TITLE: FMVSS INTERPRETATION TEXT: This responds to your April 24, 1978, letter asking two questions concerning Standard No. 222, School Bus Passenger Seating and Crash Protection. In your first question, you ask what the National Highway Traffic Safety Administration (NHTSA) means by the phrase "seat components shall not separate at any attachment point." This phrase is found in the forward and rearward loading performance tests. You suggest that the NHTSA interpret this to mean a complete separation of a seat component from another component. The NHTSA disagrees with this suggestion. The standard as written clearly indicates that the agency has intended that seat components remain connected at all attachment points during testing. If the agency had intended a complete separation of seating components to be the test for separation, it would have used that language in the drafting of the regulation. Therefore, the agency declines to adopt the interpretation that you suggest and will require the seat to remain attached at all attachment points during testing. Your second suggestion concerns a possible problem in the computation of loads during rearward testing. You state that occasionally the loading bar will become buried in the upholstery material and, therefore, distort the actual seat loads. The NHTSA has not noted the phenomenon to which you refer. However, if it were to occur in compliance testing the agency would be certain to factor out any aberrations in the test results that occurred owing to this loading bar problem. SINCERELY, April 24, 1978 Joseph J. Levin Chief Counsel National Highway Traffic Safety Administration Dear Mr. Levin: The purpose of this letter is to seek a clarifying interpretation on two issues relating to FMVSS 222. 1. S 5.1.3 (e) and S 5.1.4 (e) state that during the forward and rearward performance tests respectively that "seat components shall not separate at any attachment point." It has been brought to my attention that this phrase is subject to extreme interpretation which we don't believe National Highway Traffic Safety Administration intended. For example, if 1 out of 100 spotwelds attaching a seatback panel to the frame failed, creating a local separation, would this be considered a non compliance per S 5.1.3 (e) or S 5.1.4 (e)? We have not used this interpretation. The reasoning for this is that the seat component (back panel) has not separated from the frame. This is only one example. The same problem occurs in attaching the seat riser to the main frame etc., etc. Without a clear cut definition of "separate" it is impossible to deal with this phrase. For example, would a torn bracket at a bolt attachment point be a separation? If so, how long must the tear be? Therefore, we believe the only workable interpretation of S 5.1.3 (e) and S 5.1.4 (e) is to define "separate" as complete separation of one seat component from another; i.e. separation of the seat foot from the riser from the main frame etc. We solicit your concurrence with this interpretation. 2. The second item deals with S 5.1.4 Seat performance rearward and S 6.5 loading bar. S 6.5 requires the loading bar to be 4" narrower than the seat width to insure that panel type members are secured in a manner adequate to transmit loads to main seat frame members. We agree with this philosophy. However, in our testing and development program we have noted an intermitent problem which is directly related to the "narrow" load bar but does not affect seat performance in any way. The problem is that occasionally the "narrow" load bar will bury itself in the upholstery, padding, and sheet metal and hang up. When this occurs, the load bar begins pulling the seat back in tension creating high apparent loads rather than sliding along the upholstery and only sensing seat back bending loads. Because these tension loads build rapidly, (and exceed 2200 pounds) this phenomenon could be misinterpreted as a seat back which is too rigid. This phenomenon is intermitent and not always repeatable. It occurs on different seat designs and appears to be related to parameters difficult to define such as padding thickness, the hardness of the loading bar spherical ends, and the coefficient of friction of the upholstery. One possible solution, if this should occur during compliance testing, is to use the test results from the "narrow" bar test to prove the integrity of the panel to frame attachment and use a wider bar to get true results of seat back performance. The purpose of this discussion is to go on record as acknowledging this phenomenon and seek confirmation from National Highway Traffic Safety Administration that this would not be judged a non compliance if encountered during compliance testing. We look forward to your early response on these issues. W. G. Milby Manager, Engineering Services |
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ID: nht78-1.4OpenDATE: 12/06/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Saab-Scania of America, Inc. TITLE: FMVSS INTERPRETATION TEXT: NOA-30 Mr. Ralph T. Millet Director, Governmental Relations Saab-Scania of America, Inc. Saab Drive, P. O. Box 697 Orange, Connecticut 06477 Dear Mr. Millet: This is in response to your letter of 25 October 1978 concerning the requirements of S3.3 of Standard No. 201 as it applies to the instrument panel compartment door in the Saab 900. Your specific concern is the portion of S3.3 that provides, "Additionally, any interior compartment door located in an instrument panel or seat back shall remain closed when the instrument panel or seat back is tested in accordance with S3.1 and S3.2." According to your letter, the hinges on the Saab 900 instru- ment panel compartment door are designed to deform to keep the compartment door closed if deformation resulting from the head impact requirements of S3.1 is great enough to open the compartment latch. If the instrument panel compartment door remains closed during the head impact tests of S3.1, the vehicle complies with that aspect of the requirements of S3.3 of Standard No. 201. The standard does not specify that the latch mechanism remain closed, only that the door "shall remain closed." This interpretation should not be construed as an approval of Saab's instrument panel compartment door hinge system. Federal motor vehicle safety standards are written primarily in terms of performance requirements which must be met in specified tests, and a manufacturer is free to use any design it wishes to meet those performance requirements. Thus, this agency does not grant approval of specific systems or components in the vehicle. The manufacturer must exercise due care to assure that its vehicles comply with all applicable safety standards. Please let me know if you have any further questions. Sincerely, Joseph J. Levin, Jr. Chief Counsel Chief Counsel October 25, 1978 Chief Counsel National Highway Traffic Safety Administration U.S. Department of Transportation Washington, D. C. 20590 Subject: Interpretation of Paragraph S3.3 of FMVSS 201 Dear Sir: Paragraph S3.3 of Federl Motor Vehicle Safety Standard #201 states: "Interior compartment doors. Each interior compartment door assembly located in an instrument panel, console assembly, seat back, or side panel adjacent to a designated seating position shall remain closed when tested in accordance with either S3.3.1(a) and S3.3.1(b) or S3.3.1(a) and S3.3.1(c). Additionaly, any interior compartment door located in an instrument panel or seat back shall remain closed when the instrument panel or seat back is tested in accordance with S3.1 and S3.2. All interior compartment door assemblies with a locking device must be tested with the locking device in an unlocked position. When the Saab 900 instrument panel and compartment door is so tested, the compartment door remains in a closed position. However, in certain head form impact directions, it may occur that the latch disengages and no longer keeps the door closed. The only acceptable solution we could find to this problem was to design the hinges of the compartment door so that if the deformation after impact is large enough to open the latch, the hinges will deform in such a way that the door thereby remains closed. We would appreciate your opinion as to whether or not the door remaining closed by the designed locking action of the hinges is considered to be in compliance with Paragraph S3.3 of the Standard. Very truly yours, SAAB-SCANIA OF AMERICA, INC. Ralph T. Millet Director, Governmental Relations RTM:s |
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ID: nht76-5.35OpenDATE: 11/02/76 FROM: AUTHOR UNAVAILABLE; Frank A. Berndt; NHTSA TO: Yokohama Tire Corp. TITLE: FMVSR INTERPRETATION TEXT: I am writing to confirm your October 15,1976, telephone conversation with Mark Schwimmer of this office, concerning the effective dates of the Uniform Tire Quality Grading Standards (UTQGS) (49 CFR Part 575.104). As Mr. Schwimmer explained, (i) the National Highway Traffic Safety Administration has not yet established new effective dates for the UTQGS regulation; (ii) when the new effective dates are established, they will be announced in the Federal Register; and (iii) the interval between the announcement of the effective dates and the dates themselves will be sufficient to allow manufacturers to prepare for compliance with the regulation. For your convenience, an information sheet entitled "Where to Obtain Motor Vehicle Safety Standard and Regulations" is enclosed. |
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ID: nht76-5.36OpenDATE: 05/11/76 FROM: VETTER FOR JAMES B. GREGORY -- NHTSA TO: Ford Motor Company TITLE: FMVSR INTERPRETATION TEXT: I am writing to inform you that the National Highway Traffic Safety Administration (NHTSA) will, for a limited time, refrain from enforcing one portion of 49 CFR Part 575, Consumer Information Regulations. Subpart B of Part 575 specifies certain items of consumer information that apply to motor vehicles and their tires. Section 575.6 in Subpart A requires this information to be delivered to first purchasers (paragraphs (a) and (b)), made available to prospective purchasers (paragraph (c)) and submitted to the NHTSA (paragraph (d)). In particular, @ 575.6(d) requires that: Each manufacturer of motor vehicles . . . shall submit to the Administrator 10 copies of the information specified in Part B of this part that is applicable to the vehicles or tires offered for sale, at least 30 days before that information is first provided for examination by prospective purchasers pursuant to paragraph (c) of this section. I understand that the strike by the United Rubber Workers has, by cutting off the supply of new tires, created an emergency situation within the motor vehicle industry, making it difficult for a manufacturer to know more than several days before it completes a vehicle which tires will be available for installation on the vehicle. I understand further that the provision of such information to the NHTSA 30 days before it is made available to prospective purchasers has become virtually impossible. In view of the impracticability under the current circumstances of the 30-day-notice requirement, the NHTSA has concluded that enforcement of the requirement at this time is inappropriate. Accordingly, with respect to vehicles offered for sale during the strike and the 60-day period following its settlement, the NHTSA will refrain from enforcing the 30-day-notice requirement in @ 575.6(d). Submittals of information to the agency must continue to be made, however, not later than the time the information is made available to prospective purchasers. With respect to vehicles that will be offered for sale at the expiration of the 60-day period, the NHTSA expects to begin receiving submittals after the thirtieth day following settlement of the strike. Please note that the requirements of paragraphs (a), (b), and (c) of @ 575.6, as well as Federal Motor Vehicle Safety Standard No. 110, Tire Selection and Rims -- Passenger Cars, are not affected by this letter. |
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ID: nht76-5.37OpenDATE: 03/03/76 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Hogan & Hartson TITLE: FMVSR INTERPRETATION TEXT: I am writing in response to your letter of December 5, 1975, and your subsequent conversation with Mark Schwimmer of this office, concerning a vehicle manufacturer's duty to provide consumer information pursuant to 49 CFR 575.104, Uniform Tire Quality Grading Standards. Your letter included a sample information sheet for the model 240D with Dunlop 185 SR 14 tires. For that model equipped with those tires, the format of the sheet would meet the requirements of @ 575.104(d)(1)(iii) for information to be furnished to the first purchaser of a new motor vehicle. Similarly, if the vehicle is offered for sale only with those tires, the format would meet the requirements of @ 575.104(d)(1)(iii) for information to be furnished to prospective purchasers. Please note that the stay of this regulation, issued last August by the U.S. Court of Appeals for the Sixth Circuit, is still in effect. |
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ID: nht76-5.38OpenDATE: 05/20/76 FROM: AUTHOR UNAVAILABLE; John Womack; NHTSA TO: Earl M. Hoosline TITLE: FMVSR INTERPRETATION TEXT: This is in response to your letter of April 11, 1976, requesting information concerning your daughter's purchase of a 1972 Plymouth whose odometer was allegedly rolled back. The Motor Vehicle Information and Cost Savings Act (Pub. L. 92-513) prohibits alteration of the mileage indicated on an odometer and requires that a written disclosure of a vehicle's mileage be provided by the seller to the purchaser at the time the ownership of a vehicle is transferred. If the correct mileage is unknown, however, the Act requires a statement to that effect to be furnished in written form to the buyer. There is no requirement that these disclosure statements be retained by either the transferor or the transferee. Violation of any of the above requirements may subject the violator to civil liability where his actions were intended to defraud the purchaser. The Act makes available to the buyer a remedy in the amount of $ 1,500 or treble damages, whichever is greater. To obtain this remedy, section 409 of the Act provides that a private civil action be instituted in State or Federal court. If a vehicle has traveled over 100,000 miles and this is not reflected on the odometer, the odometer disclosure statement should indicate that the mileage registered on the odometer does not reflect the true number of miles the vehicle has driven. If the suggested Federal form is used in making the disclosure, the following statement should be checked: "I further state that the actual mileage differs from the odometer reading for reasons other than odometer calibration error and that the actual mileage is unknown." However, since the actual mileage would be known in the case where the odometer had simply passed the 100,000 mark, the seller should state what the actual mileage is. For your information, I am forwarding copies of the relevant portions of the Act and the disclosure requirements, in addition to the consumer information pamphlet on odometers. SINCERELY, DEAR SIRS: Legal April, 11, 1976 Would like a little information on odometer tampering law: Daughter bought a 197 plymouth (SECOND HAND) actual miles on odometer card 45,800 miles. Drove 2000 miles and had to have over hauled mechanic stated the car had much over the named mileage how far back does odometer check have to be kept -- my understand, was owned & sold by at least two dealers before us. If the car has gone over the 100, thousand mark does that all have to be shown on paper, please let me know by returned mail if any information would be helpful to me & others Thank you Earl M. Hoosline |
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.