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: aiam5096OpenEmmett Koelsch Coaches ATTN: Kim Welsh 926 Delaware Longview, WA 98632; Emmett Koelsch Coaches ATTN: Kim Welsh 926 Delaware Longview WA 98632; "Dear Sir/Madam: Your letter of November 5, 1992 addressed to th Department of Transportation Publications Department was forwarded to this office for response. In your letter you requested a copy of the Federal motor vehicle safety standards pertaining to school buses 'and other Transit type vehicles.' The Federal motor vehicle safety standards issued by this agency, the National Highway Traffic Safety Administration (NHTSA), apply to all classes and categories of motor vehicles, including passenger cars, trucks, buses of all types including school buses, multipurpose passenger vehicles, and the like. Excluded from the definition of motor vehicles are such vehicles as farm tractors, earth-moving equipment, and other off-road vehicles. For your information, I am enclosing a pamphlet issued by this agency entitled Federal Motor Vehicle Safety Standards and Regulations, which summarizes our safety standards. Also enclosed are copies of two fact sheets issued by this office entitled Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment and Where to Obtain NHTSA's Safety Standards and Regulations. You did not elaborate on what was meant by 'Transit type vehicles.' If you were referring to intercity buses, you should contact the Office of Motor Carrier Standards, Federal Highway Administration, Room 3404, this address for information on their pertinent standards and regulations. For information on intracity buses, you should contact the Federal Transit Administration, Room 9328, this address. Finally, for information regarding implementation of the Americans with Disabilities Act, you should contact the Office of Technical and Information Services, U.S. Architectural and Transportation Barriers Compliance Board, 1331 F Street N.W., Suite 1000, Washington, DC 20004-1111. I hope this information is helpful. If after examining this material you have more specific questions, please feel free to contact Mr. Walter Myers of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosures"; |
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ID: aiam1500OpenMr. Jim Coughlin, Vice President-Marketing, Bell Helmets Inc., 2850 East 29th Street, Long Beach, CA 90806; Mr. Jim Coughlin Vice President-Marketing Bell Helmets Inc. 2850 East 29th Street Long Beach CA 90806; Dear Mr. Coughlin: This is in reply to your letter of May 1, 1974, concerning th requirements of Standard No. 218, *Motorcycle Helmets*. You mentioned that Bell is producing some helmets to the Snell standard 'irrespective of the DOT standard,' and you enclosed the labels Bell is using to allow the consumer to differentiate the helmets produced to the Snell standard. The labels you enclosed contain the following notice:; >>>*IMPORTANT*: THIS HELMET IS MANUFACTURED FOR RACING AND OTHER HIG PERFORMANCE USES ONLY, AND IS NOT REGULATED BY THE U.S. DEPT. OF TRANSPORTATION. IT IS NOT FOR USE ON PUBLIC STREETS, ROADS AND HIGHWAYS.<<<; We do not consider this notice acceptable. We believe that the phrase '...AND OTHER HIGH PERFORMANCE USES ONLY...,' would mislead the consumer into thinking that a helmet with this notice is safer for use on public roads than a helmet produced to Standard 218. Accordingly, the phrase '...and other high performance uses only...' should not be used to describe the purpose of helmets produced to the Snell standard. Instead, we suggest that the following language be inserted: '...and similar off- road sports only...'.; You also ask how to determine which helmets you manufacture qualify a 'fitting' the size C headform. Any 'fit-all' or other helmets that are designed to fit a range of head sizes that includes the approximate dimensions of the size C headform must meet the requirements of Standard 218. A helmet is considered not to fit a size C headform only if it is clearly intended by its manufacturer to be used only by persons whose heads are either larger or smaller than the size C headform.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1501OpenMr. Jim Coughlin, Vice President-Marketing, Bell Helmets Inc., 2850 East 29th Street, Long Beach, CA 90806; Mr. Jim Coughlin Vice President-Marketing Bell Helmets Inc. 2850 East 29th Street Long Beach CA 90806; Dear Mr. Coughlin: This is in reply to your letter of May 1, 1974, concerning th requirements of Standard No. 218, *Motorcycle Helmets*. You mentioned that Bell is producing some helmets to the Snell standard 'irrespective of the DOT standard,' and you enclosed the labels Bell is using to allow the consumer to differentiate the helmets produced to the Snell standard. The labels you enclosed contain the following notice:; >>>*IMPORTANT*: THIS HELMET IS MANUFACTURED FOR RACING AND OTHER HIG PERFORMANCE USES ONLY, AND IS NOT REGULATED BY THE U.S. DEPT. OF TRANSPORTATION. IT IS NOT FOR USE ON PUBLIC STREETS, ROADS AND HIGHWAYS.<<<; We do not consider this notice acceptable. We believe that the phrase '...AND OTHER HIGH PERFORMANCE USES ONLY...,' would mislead the consumer into thinking that a helmet with this notice is safer for use on public roads than a helmet produced to Standard 218. Accordingly, the phrase '...and other high performance uses only...' should not be used to describe the purpose of helmets produced to the Snell standard. Instead, we suggest that the following language be inserted: '...and similar off-road sports only...'.; You also ask how to determine which helmets you manufacture qualify a 'fitting' the size C headform. Any 'fit-all' or other helmets that are designed to fit a range of head sizes that includes the approximate dimensions of the size C headform must meet the requirements of Standard 218. A helmet is considered not to fit a size C headform only if it is clearly intended by its manufacturer to be used only by persons whose heads are either larger or smaller than the size C headform.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5130OpenMr. Dale E. Dawkins Director Vehicle Compliance and Safety Affairs Chrysler Corporation CIMS 415-03-17 1200 Chrysler Drive Highland Park MI 48288-0857; Mr. Dale E. Dawkins Director Vehicle Compliance and Safety Affairs Chrysler Corporation CIMS 415-03-17 1200 Chrysler Drive Highland Park MI 48288-0857; "Dear Mr. Dawkins: This responds to your letter of December 16, 1992 to the Administrator informing the agency about the intent of Chrysler Corporation to manufacture 10 Chesapeake Consortium Electric Vehicles (CCEV) under NHTSA Temporary Exemption 92-1. According to your letter, these vehicles are 'almost identical' to the TEVans for which the agency granted the temporary exemption, except that they will utilize an AC electrical motor, while the ones which were the subject of the exemption petition will be powered by a DC electrical motor. You seek no broader exemption as the combined volumes of CCEVs and TEVans 'will not exceed the maximum units of the petition that was granted.' You have submitted this information to us so that NHTSA will have a clear understanding of the content of your electric vehicle development program and the extent of the exemptions under which these vehicles will be manufactured. It appears that you would like confirmation from NHTSA that the CCEV vehicles are covered by Temporary Exemption 92-1. In order for the agency to provide this confirmation, it must determine that CCEV and TEVans are essentially the same vehicle and that none of the minor differences between the vehicles affects the findings made by the agency in issuing the TEVan exemption. In granting Chrysler's exemption petition covering three standards, the Administrator first found that the exemption would facilitate the development and field evaluation of a low emission motor vehicle. We do not believe that the change in electrical propulsion from DC to AC affects this finding. The Administrator next found that an exemption from the three standards would not unduly degrade the safety of the vehicle. You state that ' b ased on our engineering judgement, there is no significant difference between the CCEV or TEVan in terms of overall vehicle safety.' While you may have used the word 'significant' in an excess of caution, it implies that there are differences between CCEV and TEVan and that there is a difference in overall vehicle safety between the CCEV and TEVan, although not an important one from Chrysler's viewpoint. We would appreciate your identification of the differences between the vehicles, and of the differences, if any, in the safety between the CCEVs and TEVans that may have led to Chrysler's engineering conclusion. With this information, we shall be better able to evaluate whether the two vehicles are essentially the same and whether there is any undue degradation in safety that might render it inappropriate to consider the CCEVs covered by the TEVan exemption. We appreciate your calling our attention to this matter. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0866OpenMr. Douglas MacGregor, TERRALAB, 5221 Major Street, Salt Lake City, UT, 84104; Mr. Douglas MacGregor TERRALAB 5221 Major Street Salt Lake City UT 84104; Dear Mr. MacGregor: This is in reply to your letter of August 31, 1972, to Robert C O'Connell, Region VIII Administrator for the National Highway Traffic Safety Administration, concerning the application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials'. You raise several questions in your letter which are restated below.; 1. 'Does the standard apply to wood paneling used on the interior o campers, trailers, and mobile homes?'; The standard applies to passenger cars, multipurpose passenge vehicles, trucks, and buses. This does not cover trailers, a vehicle class that includes mobile homes among its members, but it does cover campers which are mounted on new chassis. Accordingly, wood paneling used as a component or portion of a component described in Paragraph S4.1 of the standard and installed in campers mounted on new chassis would be subject to the requirements of the standard.; 2. You ask whether the standard applies to the studs used to fasten th wood paneling to the structural framework.; The studs used to fasten the wood paneling to the structural framewor of campers mounted on new chassis are not listed in Paragraph S4.1 of the standard, nor are they incorporated into a component listed in Paragraph S4.1. Consequently, the studs would not be subject to the requirements of the standard.; 3. 'Does the standard apply to plastic door molding?' Paragraph S4.1 does not list door molding as one of the interio components that must meet the requirements of the standard and, therefore, door molding is not covered.; 4. 'Does the standard apply to carpeting, and if so, if the carpetin is tacked to the flooring, does the flooring have to be tested for flammability?'; Paragraph S4.1 lists 'floor coverings' among the components required t meet the requirements of the standard. Since carpeting is a floor covering, it would have to meet the requirements of the standard. The flooring underneath the carpeting would not be considered a 'floor covering' and, accordingly, would not have to meet the requirements of the standard.; 5. 'If the paneling or flooring, either separately or as a subassembly has to be tested, is it tested by this procedure, or a more applicable procedure such as ASTM E251, etc.?'; The flooring, as stated above, is not subject to the requirements o the standard when it is covered by a floor covering such as carpeting. While a manufacturer may test for conformity to the standard as he thinks best, whether his product conforms to the standard will be determined by the NHTSA by means of the test procedures specified in the standard. Manufacturers who use procedures different from those in the standard should correlate the results obtained from such tests with those that would be obtained by the procedures recommended by the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel. |
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ID: aiam4921OpenCarl Miller, O.E. Sales Manager DICO Tire, Inc. 520 J.D. Yarnell Industrial Parkway Clinton, TN 37716; Carl Miller O.E. Sales Manager DICO Tire Inc. 520 J.D. Yarnell Industrial Parkway Clinton TN 37716; "Dear Mr. Miller: This responds to your letter asking about th application of 49 CFR Part 574, Tire Information and Recordkeeping, to new tires sold in the replacement market. You indicated that, as a manufacturer of boat trailer tires, you believed that Part 574 required you to provide recall information cards for every new tire, whether that tire was to be installed as original equipment or sold in the replacement market. You added, however, that you heard that the National Highway Traffic Safety Administration (NHTSA) had recently restricted the application of this requirement to tires sold as original equipment. Accordingly, you requested the agency to confirm that information. NHTSA has made no amendments to Part 574 that would restrict the requirement that tire manufacturers provide recall information cards only for those tires sold as original equipment. Hence, tire manufacturers remain subject to the requirement that they provide such cards to every distributor and dealer that sells the manufacturer's new tires, regardless of whether those new tires are sold as original equipment on a vehicle or as an individual replacement item. Part 574 sets forth tire information and recordkeeping requirements to facilitate notification of purchasers in the event that a manufacturer must recall a tire to remedy a safety-related defect, or a noncompliance with an applicable Federal Motor Vehicle Safety Standard. Among Part 574's requirements, 574.7 specifies requirements for tire registration forms. I believe these forms are what your letter refers to as 'recall information cards.' 574.7 requires each new tire manufacturer and each new tire brand name owner (or its designee) to provide tire registration forms to every distributor and dealer of its tires which offers 'new tires for sale or lease to tire purchasers.' 49 CFR 574.7(a)(1) Part 574 defines 'tire purchaser' as 'a person who buys or leases a new tire, or who buys or leases for 60 days or more a motor vehicle containing a new tire for purposes other than resale.' 49 CFR 574.3(5) Thus, 574.7(a)(1) explicitly requires that tire registration forms be provided to every distributor or dealer that offers a manufacturer's new tires for sale to the public. 574.7 makes no distinction between tires to be sold as original equipment and tires sold as replacement products. For your information, I have enclosed a copy of 49 CFR Part 574 and have highlighted the provisions that relate to your question. I hope this information is helpful. Please contact Elizabeth Barbour of my staff at this address or by telephone at (202) 366-2992 if you have further questions. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam2034OpenMr. H. Melvin Strand, President, Duo-matic Importers LTD., P.O. Box 1436, Colorado Springs, CO 80901; Mr. H. Melvin Strand President Duo-matic Importers LTD. P.O. Box 1436 Colorado Springs CO 80901; Dear Mr. Strand: This responds to Duo-matic's August 19, 1975, question whether Standar No. 121, *Air Brake Systems*, applies to an air brake coupler device that connects air brake hoses from a truck to the trailer it tows.; The answer to your question is no. Paragraph S3 (Applicability) o Standard No. 121 states that the standard applies to trucks, buses, and trailers equipped with air brake systems (with some stated exceptions). The standard therefore applies only to vehicles, and does not apply to motor vehicle equipment such as the Duo-matic coupler device.; Sincerely, Frank Berndt, Acting 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: aiam4846OpenMr. Jerry Tassan 177 Airport Blvd San Francisco, CA 94080; Mr. Jerry Tassan 177 Airport Blvd San Francisco CA 94080; "Dear Mr. Tassan: This responds to a telephone inquiry in which yo explained to Mr. Stephen Wood, the Assistant Chief Counsel for Rulemaking, that your truck rental company is considering lowering the Gross Vehicle Weight Rating (GVWR) of some of its used trucks so that a renter need not have a commercial driver's license to operate them. You asked how the regulations of this agency, the National Highway Traffic Safety Administration (NHTSA), would apply to such an action. As explained below, because only a manufacturer can assign a GVWR, any modification of a vehicle's GVWR by parties that are not manufacturers would have no legal effect. By way of background information, NHTSA is authorized by the National Traffic and Motor Vehicle Safety Act ('Safety Act') to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA is not authorized to certify or approve motor vehicles or motor vehicle equipment for compliance with our Federal safety standards. Instead, under the Safety Act, each manufacturer of motor vehicles and motor vehicle equipment is responsible for certifying that its products meet all applicable safety standards. The Certification requirements in 49 CFR Part 567 require each manufacturer to affix to the vehicle a label containing, among other things, the vehicle's GVWR. Under Part 567, the only parties that can assign or modify a vehicle's GVWR are the original manufacturer (567.4(g)(3)), a final stage manufacturer (567.5(c)(5)), or an alterer (567.7(b)). Modifications of GVWR by any other parties would have no legal effect under Part 567. Accordingly, a vehicle owner that performs no manufacturing operations on a vehicle cannot modify the GVWR of the vehicle. You should also be aware that another Federal authority - the Federal Highway Administration's (FHWA's) Office of Motor Carrier Standards - may regulate your attempts to lower a vehicle's GVWR. The FHWA regulates the licensing of operators of 'commercial motor vehicles' under the Commercial Motor Vehicle Safety Act of 1986. I recommend you contact Mr. James Scapellato, Office of Motor Carrier Standards, HCS-1, FHWA, 400 Seventh Street, SW, Washington, D.C. 20590 if you have any further questions about driver licensing. I hope this information is helpful. If you have any further questions about the GVWR assigned to vehicles, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam5090OpenMr. T. Kouchi Director & General Manager Automotive Equipment Development & Administration Dept. Stanley Electric Co. Ltd. 2-9-13, Nakameguro-ku, Meguro-ku Tokyo 153, Japan; Mr. T. Kouchi Director & General Manager Automotive Equipment Development & Administration Dept. Stanley Electric Co. Ltd. 2-9-13 Nakameguro-ku Meguro-ku Tokyo 153 Japan; "Dear Mr. Kouchi: This responds to your letter of October 8, 1992, wit respect to photometric test methods for a center high-mounted stop lamp using light emitting diodes (LEDs) as light sources. Your letter presents certain procedures and asks for associated revisions in Federal Motor Vehicle Safety Standard No. 108. After review, we have come to the conclusion that your method of proposed testing is allowable under Standard No. 108, but more stringent than what the standard requires. In the section of your letter called 'BACKGROUND', you state that you usually follow the technical guidance of SAE J1889 as a standard practice for LED lighting devices. There is no requirement in Standard No. 108 or in any of the SAE standards incorporated by reference in Standard No. 108 that requires you to follow the test methodology of J1889. Thus, when you say that you 'must always allow a margin of the same percentage when designing initial light output of the lamp, which necessitates increase in the number of LEDs used, lamp size, product cost, and, therefore, user's expense', you are placing a burden upon yourself that does exist under J1889, but one which is not necessary for designing for compliance with Standard No. 108. You have proposed a solution for the problem you have created by following J1889, and you provide three specific reasons in support. The third reason is based upon your interpretation of SAE J575's warpage test, under which you test operating cycles of 5 minutes on and 5 minutes off. However, you reference a version of J575 which does not apply to center high-mounted stop lamps. Paragraph S6.1 of Standard No. 108 specifies that J575e, August 1970, applies to high-mounted stop lamps designed to conform to SAE Recommended Practice J186a. SAE J575, August 1970, simply specifies that the device is to be operated in the test in the same manner as it will be operated in service, far different than the cycle method you employ. Thus, you have requested that we revise Standard No. 108 by adding a new provision that center high-mounted stop lamps shall be energized for a minimum of 5 minutes before measurement of photometric minima. We note that nothing prohibits you from testing in such a manner, but we believe that an amendment of this nature is not required because the present allowable method of testing does not call for it. You have asked for our comments on four steps of photometric measurement, and our permission to follow them. There is no reason you may not follow them, if you wish, but they are unnecessary to design for compliance under Standard No. 108. I hope that this is responsive to your questions. Sincerely, Paul Jackson Rice 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.