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
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ID: aiam2358OpenMr. J. W. Lawrence, Manager, Safety and Environmental Engineering, White Motor Corporation, P.O. Box 91500, Cleveland, OH 44101; Mr. J. W. Lawrence Manager Safety and Environmental Engineering White Motor Corporation P.O. Box 91500 Cleveland OH 44101; Dear Mr. Lawrence: This responds to White Motor Corporation's April 26, 1976, questio whether S5.3.3 and S5.3.4 of Standard No. 121, *Air Brake Systems*, require minimum brake chamber air pressures of 60 psi and 95 psi, respectively, or whether these air pressures are included in the sections only as 'bench marks' on which to base specifications for minimum actuation and release timing in brake systems. Section S5.3.3 specifies in part:; >>>. . .With an initial service reservoir system air pressure of 10 psi, the air pressure in each brake chamber shall, when measured from the first movement of the service brake control, reach 60 psi in not more than 0.45 seconds. . . .<<<; Your understanding that S5.3.3 and S5.3.4 only specify the ai pressures of 60 psi and 95 psi as the basis for timing requirements is correct. Neither value is intended as a requirement that the vehicle be designed to provide a certain level of brake chamber air pressure. The values were based on an understanding of the typical configuration of existing air brake systems at the time the final rule was issued.; In response to your request for interpretation of these sections i view of White's intent to use a lower air pressure than was commonly used in the past, the agency will utilize the stated 60-psi value or a value that is 70 percent of a maximum air pressure (measured by the NHTSA at the brake chamber), whichever is lower. In the case of release, the stated 95-psi value or the value that represents maximum air pressure (measured by the NHTSA at the brake chamber), whichever is lower, will be used. For purposes of this determination, the maximum air pressure in the brake chamber is that obtainable with full brake application when the pressure in the service reservoir is at 100 psi. Use of the maximum air pressure application timing would be unreasonable because of the decreased rate of air pressure build-up that occurs as the brake chambers reach maximum pressure.; The agency will issue an interpretive amendment to S5.3.3 and S5.3.4 t reflect this interpretation.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam0365OpenMr. A. J. Holland, Triplex Safety Glass Co. Ltd., King's North Birmingham B38 8SR, England; Mr. A. J. Holland Triplex Safety Glass Co. Ltd. King's North Birmingham B38 8SR England; Dear Mr. Holland: This is in reply to your letter of May 28, 1971, concerning the markin requirements in the proposed amendment to Standard No. 205, 'Glazing Materials' (Docket No. 71-1, Notice 1). These requirements are only proposed at present, as is their effective date, and do not represent the agency's final decision on the matter. If the agency determines to amend the standard, and before any compliance with new requirements is required, a 'final rule' will be issued that is based on the proposed rule but may differ in some respects from it. The final rule will specify an effective date for these new requirements which, in this instance, will probably be later than the effective date proposed.; You ask whether the effective date of the proposed standard would appl to the manufacture of the glazing, or to the fitting of the material into the vehicle. Standard No. 205 applies to 'glazing materials for use in passenger cars, multipurpose passenger vehicles, motorcycles, trucks and buses', and the effective date of any amendment to this standard refers to the date of manufacture of the glazing material, and not to its fitting into the vehicle.; Your second question, whether we will accept your marking without hyphen between the 'DOT' symbol and your code mark, has been answered in our letter to you of May 26, 1971.; I hope this clarifies the situation. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam5167OpenMr. John B. White Industry Standards & Government Regulations Michelin Post Office Box 2501 Greenville, SC 29602; Mr. John B. White Industry Standards & Government Regulations Michelin Post Office Box 2501 Greenville SC 29602; "Dear Mr. White: This responds to your letter asking the Nationa Highway Traffic Safety Administration (NHTSA) to clarify our certification procedures for the information of some of your customers. Specifically, you stated that some customers believe that you are required to test your tires for compliance with the Federal motor vehicle safety standards (FMVSS) and the Uniform Tire Quality Grading Standards (UTQGS), and that this agency then certifies your tires after reviewing and evaluating your test results. Those impressions are incorrect. All new tires sold in the United States for use on passenger cars must be certified by the manufacturer as complying with FMVSS 109, New pneumatic tires, found at 49 CFR 571.109, while all new tires sold for use on motor vehicles other than passenger cars must be certified as complying with FMVSS 119, New pneumatic tires for vehicles other than passenger cars, found at 49 CFR 571.119. The National Traffic and Motor Vehicle Safety Act, 15 U.S.C. 1381, et seq. (Safety Act) establishes a self-certification procedure applicable to new motor vehicles and new items of motor vehicle equipment, which includes tires. This means that the tire manufacturer, and not a governmental agency such as NHTSA, certifies that its tires comply with applicable FMVSSs. Each new tire must be certified as meeting the applicable FMVSSs regardless of whether the tire meets an equal or higher standard in another country. The UTQGS are set forth in 49 CFR 575.104. Those standards do not require certification in the same manner as the FMVSSs. The UTQGS require that manufacturers mold onto or into the sidewalls of their tires the comparative ratings of those tires for treadwear, traction, and temperature resistance for the use and benefit of consumers. Again, that is the manufacturers' responsibility and NHTSA neither reviews nor approves the ratings prior to their assignments by the manufacturers. Neither the Safety Act nor NHTSA standards and regulations require that a manufacturer base its certifications on any specific tests, any number of specified tests or, for that matter, any tests at all. A manufacturer is only required to exercise due care in certifying its tires. It is the responsibility of each tire manufacturer to determine initially what test results, computer simulations, engineering analyses, or other information it needs to enable it to certify that its tires comply with applicable Federal safety standards. Once a manufacturer has determined that its tires meet all applicable Federal safety standards, it certifies such compliance by molding the letters 'DOT' onto at least one sidewall of each certified tire. If manufacturers conduct any tests, they are not required by Federal law or regulation to release their test results to the public. This agency does not perform any pre-sale testing, approval, or certification of tires, whether of foreign or domestic manufacture, before introduction into the U. S. retail market. Similarly, NHTSA does not approve or certify manufacturers' test results. Rather, NHTSA randomly tests certified tires to determine whether the tires do, in fact, comply with applicable standards. For such enforcement checks, NHTSA purchases tires 'off the shelf' from retail tire dealers and tests those tires according to the procedures specified in the standards. If the tires pass the tests, no further action is taken. If they fail the tests and are determined not to comply with any applicable standard or standards, the manufacturer is responsible for recalling the tires and remedying the noncompliance without charge to the consumer. Government compliance test results are available to the public upon request from the NHTSA Technical Reference Division (NAD 52), 400 Seventh Street SW, Room 5108, Washington, D.C. 20590, (202) 366-2768. I hope this information will assist you in clarifying tire certification requirements to the satisfaction of your customers. If you have any further questions or desire further clarification, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam1827OpenHonorable Robert H. Mollohan, House of Representatives, Washington, DC 20515; Honorable Robert H. Mollohan House of Representatives Washington DC 20515; Dear Mr. Mollohan: This is in response to your letter of February 19, 1975, requestin information concerning correspondence from one of your constituents, Mr. Charles E. Allard, criticizing the recent proposal to reduce the performance requirements of the Federal bumper standard.; The proposal was based primarily on the results of two agency sponsore studies which indicated that the cost and weight of many current production bumpers, in light of inflation and fuel shortages, made the bumpers no longer cost-beneficial. Information presented at public hearings on the bumper notice and comments submitted to the docket in response to the proposal have brought to light additional data. The NHTSA has carefully examined all of this evidence and reviewed its studies in light of the new information. As a result, the agency has concluded that the 5-mph protection level should not be reduced. This decision is contained in a Federal Register notice that was issued on March 7, 1975 (Docket No. 74-11, Notice 7, Docket No. 73-19, Notice 6).; I would like to point out that the bumper standard, as it currentl exists, has no direct effect on occupant safety in collisions. The safety benefits of the standard relate to the prevention of damage to safety-related components such as headlamps, fuel and cooling systems, and exhaust systems. It is the after-crash dangers that would exist if a vehicle were driven with any of the specified vehicle systems inoperative that the standard focuses on. Therefore, a reduction in the performance requirements would not expose occupants to greater hazards during a collision itself.; We appreciate your interest and that of Mr. Allard. Sincerely, William T. Coleman, Jr. |
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ID: aiam2708OpenMrs. Edward Foster, Route #1, Box 416, Cleveland, NC 27013; Mrs. Edward Foster Route #1 Box 416 Cleveland NC 27013; Dear Mrs. Foster: Your recent letter to President Carter concerning the installation of bench seat in a cargo van was forwarded to the National Highway Traffic Safety Administration for reply. You were apparently told by your local Ford dealer that Federal law prohibits the installation of a seat in the cargo area of a van vehicle.; The Ford dealer's representation to you was incorrect. There is n Federal law that precludes installation of a seat such as your letter describes, although, depending on the time and manner of the installation, the seat might be subject to Federal safety standards.; If the vehicle manufacturer (Ford) or your dealer installs the sea prior to the time you take possession of the vehicle, either will have to certify that the vehicle, including the seat, is in compliance with all applicable safety standards, as provided in the National Traffic and Motor Vehicle Safety Act, as amended (15 U.S.C. 1381 *et seq*.). Specifically, the installation of the seat would require compliance with Safety Standard No. 207, *Seating Systems*, Safety Standard No. 208, *Occupant Crash Protection*, and Safety Standard No. 210, *Seat Belt Anchorages*. If done by your dealer, he would be required to attach a label or tag to the vehicle certifying that, as altered, the vehicle was in compliance with all safety standards, including the three just mentioned (49 CFR 567.7).; If you first take possession of the vehicle, you or your dealer ma then install an additional seat without certifying compliance with Federal safety standards (15 U.S.C 1397). Your dealer would, however, be subject to section 108(a)(2)(A) of the Vehicle Safety Act, which provides that no manufacturer, distributor, dealer or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle in compliance with an applicable Federal motor vehicle safety standard. This means that the dealer would not be permitted to destroy the vehicle's conformity to any safety standard by his installation of the additional seat. We do strongly recommend that, for the safety of your child, you assure the seat and safety belts conform to the minimum performance requirements of our safety standards.; Perhaps it is the policy of Ford Motor Company and its dealers not t install additional seats in cargo vans because of the responsibilities mentioned above. The policy is not, however, a Federal law. I suggest you show this letter to your local dealer.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0735OpenMr. Thomas S. Pieratt, Jr., Executive Secretary, Truck Equipment & Body Distributors Association, 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Jr. Executive Secretary Truck Equipment & Body Distributors Association 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in response to your letter of May 9, 1972, in which you aske several questions concerning certification of multistage vehicles.; Your first set of questions concerned the 'altering distributor' labe of S 567.6. In the course of administering this regulation, we have come to regard this as an 'optional' label--one that is not absolutely required in any situation. If a person altering a completed vehicle does not make changes significant enough to make him a remanufacturer who recertifies the vehicle as a manufacturer, he may satisfy the requirements by allowing the existing label to remain in place. In the four examples that you provided in paragraph 2 of your letter, we would consider the first two examples (bumper and tail gate loader) to be marginal ones in which we would probably accept a good-faith determination either way by the person making the alterations, while the last two (brake fluid and fenders) appear to be minor enough that no recertification would be necessary. This also answers your last question.; (Paragraph 4) You are right in suggesting that once a vehicle purchase takes possession of the vehicle, the standards and regulations no longer apply.; (Paragraph 5) It is true that if a person manufactures a vehicle an uses it himself, it must still conform when he sells it at a later time. To hold otherwise could create a loophole, whereby a manufacturer could make nominal use of his vehicles before selling them.; (Paragraph 6) The passage of the article on my discussion mentionin 'liability' dealt with a question on remanufactured vehicles. I don't have a transcript, but it looks as though he was quoting a couple of sentences out of context (although the article was generally good reporting). I was making the point that there could be a level of 'rebuilding' a vehicle where the work done, the parts replaced, are so extensive that we would consider it to be manufacturing. It would be an unusual situation. I was indeed referring to compliance with the standards and regulations, not product liability.; Your discussion of installation of third axles seems to reflect proper understanding of our rules.; With reference to your question in paragraph 8 about the period of tim a vehicle must be held by a customer before he can have non-standard alterations made in it, there is no set period of time. After he has 'purchased' it, he can have done with it what he wants. However, the Vehicle Safety Act S 108(b)(1), does have one important phrase on that subject: 'in good faith.' If we found that a dealer or distributor were using the first-purchase clause as a ruse to do things that the standards and regulations would not otherwise allow, we would probably do everything we could to stop it--to show that it was not in good faith.; I am glad to be of help to you and your members. I hope, however, tha you will limit your questions to situations that have actually arisen, since we do not have the resources to grapple with hypothetical questions.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5537OpenMr. Valter Sforca 84 Thomas Street Newark, NJ 07114; Mr. Valter Sforca 84 Thomas Street Newark NJ 07114; Dear Mr. Sforca: This is in reply to your letter of April 20, 1995 asking if there is a regulation that applies to the importation of an 'air equalizer for tire pressure.' Although you have not described your device, there are no Federal motor vehicle safety standards that apply to equipment installed in motor vehicles that regulate the air pressure of tires. If you are asked by the U.S. Customs Service to execute an HS-7 Declaration Form at the port of entry, you may check Box 1, declaring that the equipment was manufactured on a date when no applicable Federal motor vehicle safety standard was in effect. Because this device is motor vehicle equipment, and because you apparently would be its importer, you would be responsible for notifying buyers and recalling it if either you or we decided that it contained a safety related defect. We don't understand your phrase 'the system have a safety valve for the air brakes the truck, for a properly stop'. However, if the 'air equalizer' is installed by a manufacturer, distributor, dealer, or motor vehicle repair business, that person must not knowingly make inoperative any part of a truck's air brake system by installing the air equalizer. I am enclosing a copy of a letter concerning what appears to be a similar device, which will explain this more fully. If you have any further questions, you may refer them to Taylor Vinson of this Office, with whom you spoke previously (202-366-5263). Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam3230OpenMr. Raymond J. Salehar, Highway Safety Engineer, Motor Vehicle Administration, Maryland Department of Transportation, 6601 Ritchie Highway NE, Glen Burnie, MD 21062; Mr. Raymond J. Salehar Highway Safety Engineer Motor Vehicle Administration Maryland Department of Transportation 6601 Ritchie Highway NE Glen Burnie MD 21062; Dear Mr. Salehar: This responds to your February 8, 1980, letter asking whether it i permissible for a State to transport children to and from school on regular city transit buses. The answer to your question is yes, if the buses are on their scheduled transit routes and are transporting both school children and adults.; The National Highway Traffic Safety Administration has defined schoo bus in a way that allows buses sold for use as common carriers in urban transportation to transport school children without complying with school bus standards. This definition is located in Title 49 of the Code of Federal Regulations, Part 571.3. The agency permitted this exemption from the school bus safety standards in acknowledgment of the high costs involved in maintaining dual fleets of buses, one for school children and one for adults. Accordingly, the agency permitted cities with operating bus lines to transport children on those city buses. The agency also believes that joint bus fleets can help to conserve fuel.; The agency has made one restriction on the use of city buses t transport school children. The buses must be operating on their regular passenger routes and schedules and must not be operating on special school bus routes. Any vehicle that is operating exclusively as a school bus should be constructed in accordance with the school bus safety standards.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3660OpenMr. Gonzalie Rivers, Director, Vehicle Registration Section, Division of Motor Vehicles, 1100 New Bern Avenue, Raleigh, NC 27697; Mr. Gonzalie Rivers Director Vehicle Registration Section Division of Motor Vehicles 1100 New Bern Avenue Raleigh NC 27697; Dear Mr. Rivers: This is in response to your letter of January 24, 1983 requesting tha North Carolina be granted an exemption from the requirements of the Federal Odometer Disclosure law and its accompanying regulation. Your request is denied.; The proposed North Carolina title and transfer document does no conform with the regulation's requirements. If you wish to use the title in lieu of a separate Federal odometer statement, the transferee's (purchaser's) signature must appear on the title and transfer document. The Agency considers this signature to be essential because it is an acknowledgment that the purchaser was aware of the mileage. The purchaser, when he signs the document, is prevented from later alleging that he was not informed of the mileage or that the mileage was different from that appearing on the title. If this signature is added, the North Carolina title will satisfy the Federal odometer disclosure statement requirements.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2972OpenMr. Bruno Porrati, President, Vespa of America Corporation, 355 Valley Drive, Brisbane, CA 94005; Mr. Bruno Porrati President Vespa of America Corporation 355 Valley Drive Brisbane CA 94005; Dear Mr. Porrati: We have received your letter of January 22, 1979, petitioning for determination that a possible noncompliance with Federal Motor Vehicle Safety Standard No. 108 is inconsequential as it relates to motor vehicle safety.; This is to inform you that upon review of Mr. Levin's letter to you o March 14, 1978, and examination of the turn signal system employed on Vespa motor scooters, we have determined that there is no failure to comply with the standard and your petition is moot.; Vespa brought to our attention the fact that S4.5.6 of Standard No. 10 requires each vehicle equipped with a turn signal operating unit to have an illuminated pilot indicator but SAE Standard J488e, incorporated by reference, requires it only if turn signal lamps are not readily visible to the driver. Mr. Levin informed Vespa that, if all turn signal lamps were readily visible to the driver, no pilot indicator was necessary. Mr. Levin continued by saying:; >>>'If the driver must turn his head to the rear to check the operatio of turn signal lamps, then those lamps are not 'readily visible to the driver' and a turn signal indicator must be provided.'<<<; You have now informed us that you believe the turn signal system o Vespa motor scooter manufactured between March 1975 and the latter part of 1977 'are the functional equivalent of turn signal indicators', specifically; >>>'The turn signal systems ... are designed so that in the event of failure of either rear turn signal lamp, the appropriate front turn signal lamp will flash at three times the normal rate. As the front turn signal lamps and their flash rates are readily visible at all times to the operator, any turn signal malfunction will be readily apparent to the operator.'<<<; We agree with your conclusion. The rapid flash rate will indicate th presence of a problem in either the front or rear turn signal system and the equivalent of a turn signal indicator appears to have been provided.; Sincerely, Frank Berndt, Acting 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.