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: aiam3599OpenMr. Robert P. Donley, President, Weldon Incorporated, 2000 South High Street, Columbus, OH 43207; Mr. Robert P. Donley President Weldon Incorporated 2000 South High Street Columbus OH 43207; Dear Mr. Donley: This is in reply to your letter of December 10, 1981, regardin continuing compliance of lighting equipment after repairs.; You have asked the following questions: '1. If the original lens is replaced during a field repair by one no manufactured by the original manufacturer, would the lamp's original certification with FMVSS 108 be nullified?'; Repair of a vehicle in service is irrelevant to its certification Certification is the assurance given by the manufacturer to distributors, dealers, and purchasers, that Federal standards are met by his product upon its sale when new. There is no requirement that the certification be valid for the life of the product.; '2. Must a lamp in use remain in conformance with FMVSS 108 after suc repair is made?'; This is a good question, and the answer is no. When repairs ar necessary there is no Federal legal requirement that the lamp remain in conformance afterwards. However, manufacturers, distributors, dealers, and motor vehicle repair businesses may not alter fully functional lamps in a manner that renders them nonconforming, or substitute nonconforming equipment. This prohibition does not apply to the vehicle owner, his modifications are subject only to State and local restrictions.; '3. If the lamp must remain in conformance with FMVSS 108 after suc repair is made, who is responsible for certifying same?'; As I stated earlier, repairs of used vehicles and equipment are no subject to conformance or certification. However, if a lamp is replaced in its entirety, the manufacturer of the replacement lamp is responsible for certifying conformity to Standard No. 108 because that standard covers replacement equipment of the types you mentioned ('e.g., stop lamp, turn signal lamp, school bus warning lamp, marker lamp').; I hope this answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4749OpenMr. Douglas Mayes President Creative Products, Inc. Number One Carissa Littleton, CO 80127; Mr. Douglas Mayes President Creative Products Inc. Number One Carissa Littleton CO 80127; "Dear Mr. Mayes: This responds to your letter asking questions i relation to your product called 'gyroscopic wheel covers.' We apologize for the delay in our response. According to your letter and accompanying information, you claim that use of 'gyroscopic wheel covers' can reduce stopping distance. You stated that Dr. Carl Clark of this agency suggested that you request this office to provide a letter specifically outlining the requirements of the agency's braking test, and a list of the various testing facilities used by the agency when testing a product for this purpose. You then asked for a letter stating the 'stopping distance test guidelines' of Safety Standard No. l05, Hydraulic Brake Systems,' and a list of laboratories acceptable to DOT that could be used to test your product. You also asked whether an SAE standard is a proper example of a stopping distance test. You stated that it is your intention to use these testing standards and one of the acceptable laboratories so as to properly document your product's test results in compliance with the DOT testing standards. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its products meet applicable standards. Safety Standard No. l05, Hydraulic Brake Systems, applies to passenger cars and other motor vehicles. The standard specifies, among other things, a number of stopping distance tests that each motor vehicle must meet. I have enclosed a copy of the standard for your information. I note that Standard No. l05 was not designed for the purpose of evaluating whether a product such as yours can improve stopping distance. We are unable to offer an opinion as to the appropriateness of using Standard No. l05's stopping distance tests for that purpose, or how such a test program would best be carried out. This agency does not provide recommendations or endorsements for particular testing laboratories. I have, however, enclosed a list of the independent laboratories conducting compliance tests for NHTSA's Office of Vehicle Safety Compliance during the current fiscal year. I have also enclosed a copy of an information sheet we have prepared which provides information for new manufacturers of motor vehicles and motor vehicle equipment. I hope this information is helpful. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam3576OpenMr. Arnold P. Fuchs, 68 Roslyn Road, Grosse Pointe Shores, MI 48236; Mr. Arnold P. Fuchs 68 Roslyn Road Grosse Pointe Shores MI 48236; Dear Mr. Fuchs: This letter is to confirm your view, expressed in a telephone call wit Edward Glancy of this office, that the requirements of Standard No. 206, *Door Locks and Door Retention Components*, are not applicable to a replacement latch for a truck built in 1969.; The requirements of Standard No. 206 are applicable to passenger cars multipurpose passenger vehicles and trucks. See S2 of that Standard. However, its requirements are not applicable to replacement parts for installation in used vehicles of these types.; Further, the 'render inoperative' provisions of the National Traffi and Motor Vehicle Safety Act are not relevant to the installation of such a latch. Under section 108(a)(2)(A) of that Act, a business such as a garage must make sure that it does not knowingly render inoperative the compliance of a vehicle with any applicable safety standard. With respect to a 1969 truck and Standard No. 206, there is no compliance which could be rendered inoperative since the Standard was never applicable to that truck. That Standard applies only to trucks manufactured on or after January 1, 1972.; I would note that even in the absence of an applicable safety standard the defect provisions of the Act may be applicable. Sections 151 *et seq*. of the Act provide that manufacturers of motor vehicles and motor vehicle equipment must notify owners of vehicles and equipment with safety-related defects and remedy those defects free of charge.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4319OpenMr. Jerome A. Czarnowski, 3746 N. Tripp Avenue, Chicago, IL 60641; Mr. Jerome A. Czarnowski 3746 N. Tripp Avenue Chicago IL 60641; Dear Mr. Czarnowski: In September 1986, you sent information concerning your Emergency Ai Reserve System (EARS) to Dr. Carl Clark of the National Highway Traffic Safety Administration's (NHTSA's) Office of Research and Development. According to your letter, EARS is a separate high-pressure system intended to provide an emergency vehicle with enough air volume and pressure to charge the vehicle's integral system to operating pressure. You stated that the system does not violate the integrity of the vehicle's system, since check-valves, a relief valve and one-way regulator are present.; Later, in February 1987, you asked Dr. Clark for information concernin whether EARS is permitted under Federal Motor Vehicle Safety Standard No. 121, *Air Brake Systems*. This letter responds to that request.; By way of background information, NHTSA does not provide approvals o motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with all applicable standards. The following represents our opinion based on the facts provided in your letter.; NHTSA does not have any specific regulations covering auxiliary device for the quick pressurizing of air brake systems. However, since your device is tied into a vehicle's air brake system, it could affect a vehicle's compliance with Standard No. 121.; If your device is installed as original equipment on a new vehicle, th vehicle manufacturer is required to certify that, with the device installed, the vehicle satisfies the requirements of all applicable safety standards.; One issue we have examined is whether your device is considered a integral part of the brake system in the sense that it would need to comply with certain of Standard No. 121's requirements, e.g., those for reservoir strength. A related issue is whether certain parts of the device are considered brake hose and therefore subject to the requirements of Standard No. 106, *Brake Hoses*.; It is our opinion that your device is not considered part of th braking system, so long as the device is separated from the vehicle's main braking system by a check valve in such a way that the main braking system will not be affected by a leakage failure in the device. Thus, since your letter indicates that such a check valve is provided, your device itself would not be subject to the requirements of Standards No. 106 and 121. This opinion is limited to the specific factual situation raised by your letter. We note that the device is not intended to replace a vehicle's normal braking system but instead to provide auxiliary air pressure for certain emergency situations. We also note that the requirements of Standards No. 106 and 121 were not written to cover the high air pressures used in your system.; If the device is added to a previously certified new motor vehicl prior to its first sale, the person who modifies the vehicle would be an alterer of a previously certified motor vehicle and would be required to certify that, as altered, the vehicle continues to comply with all of the safety standards affected by the alteration.; If the device is installed on a used vehicle by a business such as garage, the installer would not be required to attach a certification label. However, it would have to make sure that it did not knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard. This is required by section 108(a)(20)(A) (sic) of the National Traffic and Motor Vehicle Safety Act.; In response to a request you made to Dr. Clark, Edward Glancy of m staff previously sent a general information sheet to your attorney, Ralph Rath, Esq. The information sheet identifies relevant Federal statutes and NHTSA standards and regulations affecting motor vehicle and motor vehicle equipment manufacturers. We are also sending a copy of this letter to Mr. Rath.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3126OpenMr. G. Frinken, Manager, Automotive Engineering Europe, Uniroyal GmbH, Postfach 410, 5100 Aachen 1, West Germany; Mr. G. Frinken Manager Automotive Engineering Europe Uniroyal GmbH Postfach 410 5100 Aachen 1 West Germany; Dear Mr. Frinken: This is in response to your letter of October 12, 1979, asking whethe the character height of 5/32nds of an inch, stated in the Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104, Figure 1), is considered by the National Highway Traffic Safety Administration (NHTSA) to specify the only acceptable height for UTQG sidewall molding, or whether the agency interprets this measurement as a minimum value.; The specification of 5/32nds of an inch tire sidewall characters wa intended by NHTSA to establish a minimum requirement to assure readability of the UTQG information presented. The agency has no objection to the use of characters of a height greater than 5/32nds of an inch, so long as all characters used to convey UTQG information are of the same height.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5158OpenMr. Scott R. Dennison Vice-President - Production Excalibur Automobile Corporation 1735 South 108th Street Milwaukee, WI 53214; Mr. Scott R. Dennison Vice-President - Production Excalibur Automobile Corporation 1735 South 108th Street Milwaukee WI 53214; Dear Mr. Dennison: Robert Hellmuth, Director of the Office of Vehicl Safety Compliance, has asked us to respond to your FAX of March 12, 1993. You offer your input and assistance 'regarding the alleged debate over the treatment of vehicles replicating pre-safety standard vehicle designs and their compliance with current Federal Motor Vehicle Safety Standards.' We are unsure what you mean by 'debate.' Under the National Traffic and Motor Vehicle Safety Act, all new motor vehicles, including replica vehicles, must conform to the Safety Standards unless exempted by the Administrator from one or more of those standards pursuant to 49 CFR Part 555. This regulation has been in effect since l972, and is intended to assist temporarily those manufacturers whose products may differ from those of conventional motor vehicles. I should note that the predecessor owners of Excalibur have been able to certify compliance of this replica vehicle since 1972 with all Safety Standards without seeking a temporary exemption from them. However, the Safety Standards do not cover a vehicle in use. Occasionally, situations arise in which a vehicle is newly manufactured, but contains a substantial number of parts from a vehicle previously in use. In these instances the question arises whether the vehicle may be considered 'new' and required to comply with the Safety Standards, or one that may be regarded as having been a vehicle in use for which compliance is not required. Perhaps this is the 'debate' to which you refer. We handle these situations according to the facts of each. If you wish to offer further comments, we would be pleased to consider them. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam2367OpenMr. Thomas S. Pieratt, Executive Director, Truck Equipment & Body Distributors Association, 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Executive Director Truck Equipment & Body Distributors Association 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This responds to your July 28, 1976, request for confirmation that boat-carrying trailer which has a primary cargo-carrying surface less than 40 inches from the ground qualifies as a 'Heavy hauler trailer', and that such trailers are not required to meet the requirements of Standard No. 121, *Air Brake Systems*, until September 1, 1977.; 'Heavy hauler trailer' is defined in the standard as follows: >>>'Heavy hauler trailer' means a trailer with one or more of th following characteristics:; (1) Its brake lines are designed to adapt to separation or extension o the vehicle frame, or; (2) Its body consists only of a platform whose primary cargo-carryin surface is not more than 40 inches above the ground in an unloaded condition, except that it may include sides that are designed to be easily removable and a permanent 'front-end structure' as that term is used in S 393.106 of this title.<<<; The boat-carrying trailer which you describe as having a bed height o 18 3/4 inches would qualify for exemption until September 1, 1977.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam5508OpenMr. Takashi Tohse Quality Assurance Group Fabricated Glass General Division Asahi Glass Company 2-1-2 Marunouchi Chiyoda-ku, Tokyo 100 Japan; Mr. Takashi Tohse Quality Assurance Group Fabricated Glass General Division Asahi Glass Company 2-1-2 Marunouchi Chiyoda-ku Tokyo 100 Japan; "Dear Mr. Tohse: This responds to your inquiry about whether variou ways of marking your automotive glazing comply with the marking requirements in Federal Motor Vehicle Safety Standard No. 205, Glazing Materials. Specifically, you ask the agency to assess the merits of what you refer to as 'plural company Ids' in your logo mark. By 'plural company Ids,' we assume you mean more than one distinctive designation or trademark. We also assume that you are a 'prime glazing material manufacturer' which the Standard defines as 'one who fabricates, laminates, or tempers the glazing material.' Under Standard No. 205, a replacement windshield is required to be marked with information that includes the prime glazing manufacturer's 'distinctive designation or trademark' and a manufacturer's code mark assigned by this agency. See, S6.1 and S6.2. You first ask, 'Can a manufacturer use different kinds of Ids for different grades of products?' The answer to this question is yes. We understand that what you refer to as 'Ids' is the manufacturer's distinctive designation or trademark. As long as an item of glazing has a manufacturer's distinctive designation or trademark, a manufacturer would comply with this requirement. The Standard does not prohibit a manufacturer from varying this distinctive designation or trademark among its different grades. (We note that each of your products would be marked with the same manufacturer's code mark that is assigned by NHTSA. This code mark will help NHTSA identify the manufacturer of the glazing material for purposes of defect and noncompliance recall campaigns.) Your second question asks 'Can a manufacturer used the same distinctive designation or trademark for two different companies?' The answer is yes. The requirements do not prohibit two companies from sharing a distinctive designation or trademark. As mentioned above, the glazing must be marked with the manufacturer's code mark that identifies the glazing's actual manufacturer. I hope this information is helpful. Please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992 if you have any further questions or need additional information. Sincerely, Philip R. Recht Chief Counsel"; |
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ID: aiam1818OpenHonorable J. Glenn Beall, Jr., United States Senate, Washington, DC 20510; Honorable J. Glenn Beall Jr. United States Senate Washington DC 20510; Dear Senator Beall: I would like to respond to your February 20, 1975, request fo consideration of Mr. R. L. Herman's views on Standard No. 121, *Air brake systems*. Mr. Herman objects that the National Highway Traffic Safety Administration (NHTSA) may have ignored the majority of comments submitted in response to its recent proposal to delay implementation of the standard, that implementation of the standard should be reconsidered by an activity other than the NHTSA, and that the new brake systems may be less safe than existing systems.; Standard No. 121 was issued as a final rule in February 1971. The NHTS realized that the economic situation in the automotive industry this past fall might justify a postponement of the scheduled January 1, 1975, effective date. In the short time available for review of the standard before its effective dates, the NHTSA issued a proposal, received comments, and made its decision.; The NHTSA concluded that net economic benefit would not be derived fro postponement. The decision was based on evaluation of all the comments, including those concerning the standard's immediate short-term impact on the national economic picture. An important factor in this case was the imminence of the standard and the degree to which financial and employment commitments were made.; As you may know, the President has directed (by Executive Order 11821 that each Federal agency consider the inflation impact of its regulatory actions. At the time of the NHTSA decision on December 31, 1974, final criteria and procedures for implementation of the Order were not yet established. The NHTSA did, however, analyze economic effects of its proposal. The NHTSA has publicly committed itself to continue monitoring the effectiveness of its standard in accordance with its statutory mandate and the President's direction, with a view to identifying any modifications that would lower costs while achieving comparable levels of safety.; An independent evaluation of the standard and its implementation by th Office of the Secretary (of the Department) was recently conducted, and this study supports the NHTSA decision. A copy of a letter regarding that evaluation is enclosed, and it discusses in detail Mr. Herman's concern about the field testing of the new braking components.; Thank you for your interest in motor vehicle safety. Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam3825OpenLawrence F. Henneberger, Esq., Arent, Fox, Kintner, Plotkin & Kahn, 1050 Connecticut Avenue, N.W., Washington, DC 20036-5339; Lawrence F. Henneberger Esq. Arent Fox Kintner Plotkin & Kahn 1050 Connecticut Avenue N.W. Washington DC 20036-5339; Dear Mr. Henneberger: This is in reply to your letter of September 26, 1983, asking for a interpretation on behalf of your client, Jacobs Manufacturing Company.; You referenced an interpretation of August 31, 1978, which we gave you also on behalf of Jacobs. Your client manufactures a diesel engine retarder system which would be provided a means to warn following drivers when the system was in use. The specific means of warning discussed in the 1978 letter was to connect the retarder activation switch to the hazard warning system, either as original or aftermarket equipment. We concluded that his installation augmented the hazard warning system, and thus did not impair the hazard warning system within the prohibition of paragraph S4.1.3 of Standard No. 108. We also concluded that it would not render inoperative the hazard warning system, and thus was not a violation of the 'anti-tampering' provision of Section 108(a)(2)(A) of the Traffic Safety Act.; Apparently, a customer of Jacobs has asked it to wire its warnin system through the stop lamps. A separate manually-operated switch will be provided. We understand that when the warning system is operational there is no difference of light intensities when the brakes are applied. You have asked us for a re-interpretation, on the basis of these new facts, that the changes retarder warning will not violate either paragraph S4.1.3 or section 108(a)(2)(A). You believe that the warning system is still permissible, because the stop lamps when so used will nevertheless indicate that the vehicle is diminishing its speed by braking, and because of interpretations by this office that retarder controls can be incorporated with the foundation brake controls and activated with the foundation brakes.; We have reviewed the 1978 interpretation allowing use of the retarde system through the hazard warning system, and the two 1974 interpretations with reference to incorporation of supplementary braking devices with foundation controls. We agree with your interpretation that the latter interpretations impliedly require activation of the stop lamps when the supplementary braking devices are used. The agency is not prepared at this time to modify either interpretation, and you may inform your client that there is no Federal legal prohibition against its wiring the retarder to activate the stop lamps when it is in use.; However, we wish to point out an area of potential risk which you client should weigh before proceeding to offer this option and which, if it occurred, could be viewed as an impairment of the stop signal within the prohibition of S4.1.3. Under the Jacobs plan, activation of the stop lamp when the retarder is engaged would indicate only a lessened rate of speed. Because there is no difference in intensity, a following driver would have no indication when the brake was applied to signal a normal or sudden stop, such as might be required when a child or animal runs into the roadway.; If you have any further questions, we shall be happy to answer them. Sincerely, Frank Berndt, Chief 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.