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: aiam5166OpenMr. Raymond S. Byers Engineering Manager, Research, Testing, and Certification Utilimaster Motor Corporation 65598 State Road #19 P.O. Box 860 Wakarusa, IN 46573; Mr. Raymond S. Byers Engineering Manager Research Testing and Certification Utilimaster Motor Corporation 65598 State Road #19 P.O. Box 860 Wakarusa IN 46573; "Dear Mr. Byers: This letter responds to your inquiry regarding th alternate placement of a vehicle certification label in your 'Aeromate' van. I apologize for the delay in responding. As you noted in your letter, 49 CFR 567.4 requires that a motor vehicle manufacturer affix a certification label to each vehicle it makes, and permits the manufacturer to place the label in any one of the places listed in that provision. If none of the listed locations is practicable, 567.4 directs the manufacturer to suggest an alternate position for the affixed label, and to request National Highway Traffic Safety Administration (NHTSA) approval for that position. You explain in your letter that in your 'Aeromate' vehicle, the driver's door slides between an inner and outer metal panel, thus making it impossible to affix the label to the hinge pillar, door-latch post, or the door edge that meets the door-latch post. Based on the photographs you included with your letter, affixing the label to the inside of the driver's side door would be unacceptable because, when opened, the door slides between the two metal panels. Thus, when the door is in the open position, the label would be obscured from the view of any observer. You propose installing the label on the inner metal panel in front of the driver's side door opening, to the left of the driver's legs under the instrument panel, and include photographs showing the label affixed to the proposed position. You state, and your photographs appear to confirm, that the location would be visible from the driver's position, and for inspection by officials. In directing a manufacturer to put its certification label in those places set out in 567.4, NHTSA's purpose is to make these labels easy to see and read. Based on the information you supplied, the agency determines that for this particular vehicle design, installing the certification label as you propose will facilitate seeing and reading the label. On the other hand, placing the label as specified in 567.4 may not be practicable and might interfere with unobstructed viewing of the label. Therefore, on the condition that your company's label complies in all other respects with 567.4, NHTSA grants your request to install the certification label on the inner metal panel in front of the driver's door opening as shown in the photographs that you provided to us. I hope this information is helpful. If you have any further questions, feel free to contact David Elias of my office at the above address or by phone, at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam1826OpenHonorable Roman L. Hruska, United States Senate, Washington, DC 20510; Honorable Roman L. Hruska United States Senate Washington DC 20510; Dear Senator Hruska: I would like to respond to your February 19, 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 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. 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.; 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. NHTSA did, however, analyze economic effects of its proposal. NHTSA has committed itself publicly 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, William T. Coleman, Jr. |
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ID: aiam0734OpenMr. Erwin Strasmich, Vice-President, Ross Matthews Corporation, East Warren Street, Fall River, MA, 02722; Mr. Erwin Strasmich Vice-President Ross Matthews Corporation East Warren Street Fall River MA 02722; Dear Mr. Strasmich: This is in reply to your letter of May 19, asking whether elasti fabric you manufacture must meet the requirements of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials' (49 CFR 571.302). You state that the fabric is under one inch wide, is tunneled and covered in automobile map pockets and similar accessories, and is not exposed in the finished product.; Paragraph S4.1 of Standard No. 302 (copy enclosed) lists the component of motor vehicles that must meet the burn rate requirements. Whether your elastic is required to meet these requirements depends upon whether it is incorporated into any of these enumerated components. We would consider, for example, a map pocket attached to the inside of a vehicle door to be part of a door 'trim panel,' and consequently subject to the standard. If your material is used in any component listed in S4.1, it would be required to meet the standard's requirements when tested as part of the component.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2709OpenMr. Terry A. Lowe, Vice President, Lowe Machine Company, State Route #2, Rural Route #3, Oak Harbor, OH 43449; Mr. Terry A. Lowe Vice President Lowe Machine Company State Route #2 Rural Route #3 Oak Harbor OH 43449; Dear Mr. Lowe: This responds to your October 12, 1977, letter asking what regulation apply to you in your capacity as an alterer of motor vehicles. The National Highway Traffic Safety Administration (NHTSA) promulgates safety standards for motor vehicles. The agency requires persons who alter motor vehicles prior to their first purchase for purposes other than resale to attach a label to each vehicle indicating that it continues to comply with all applicable safety standards. Therefore, if the modification that you intend to perform occurs prior to the first purchase of the vehicle for purposes other than resale, you would be required to attach such a label. I am enclosing a copy of Part 567, *Certification* (Volume 49 of the Code of Federal Regulations, Part 567) which addresses the responsibilities of vehicle alterers.; If you modify vehicles after their first purchase for purposes othe than resale, then you need not attach a certification or alterer's label. However, section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act of 1966 (the Act) (15 U.S.C. 1381 *et seq*.) prohibits any repair business, dealer, distributor, or manufacturer from rendering inoperative any device or element of design installed on a vehicle in compliance with a safety standard. If your manufacturing operation affected the compliance of any aspect of the vehicle with safety standards in effect on the date of the vehicle's manufacture, you would be in violation of the Act and subject to civil penalties prescribed thereunder.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5536OpenMr. 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: aiam5218OpenMr. Kenneth E. Ross 752 Hillpine Terrace Atlanta, GA 30306; Mr. Kenneth E. Ross 752 Hillpine Terrace Atlanta GA 30306; "Dear Mr. Ross: This responds to your letter requesting informatio about a product that attaches to an automobile's back window. In a telephone conversation with Marvin Shaw of my staff, you stated that your product is a two to three inch high LED sign that extends along most of the rear window. The sign displays any message that the driver chooses. While we do not have information about State or local laws, I am pleased to have this opportunity to explain the applicability of Federal law on your product. By way of background information, NHTSA is authorized to issue Federal Motor Vehicle Safety Standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA does not, however, approve or certify any vehicles or items of equipment. Instead, the National Traffic and Motor Vehicle Safety Act ('Safety Act') establishes a 'self- certification' process under which each manufacturer is responsible for certifying that its products meet all applicable Federal motor vehicle safety standards (FMVSSs). In response to your question, NHTSA currently has no FMVSSs that directly apply to the product you wish to manufacture. I note, however, that there are other Federal requirements that indirectly affect you and your product. Under the Safety Act, your product is considered to be an item of motor vehicle equipment. As a manufacturer of motor vehicle equipment, you are subject to the requirements in 151-159 of the Safety Act concerning the recall and remedy of products with safety related defects. I have enclosed an information sheet that briefly describes those responsibilities. In the event that you or NHTSA determines that your product contains a safety-related defect, you would be responsible for notifying purchasers of the defective equipment and remedying the problem free of charge. Automotive accessory equipment that a dealer adds before sale of a vehicle must not create a noncompliance with the FMVSSs to which the vehicle manufacturer has certified compliance. For instance, your LED sign should be mounted so that it does not block the field of view required by FMVSS No. 111, Rearview Mirrors. Similarly, for the vehicle to remain in compliance, your system must not impair the effectiveness of the lighting equipment required by FMVSS No. 108, Lamps, Reflective Devices, and Associated Equipment. In particular, the placement of your sign might impair the effectiveness of the center highmounted stop lamp (CHMSL) if it can be operated simultaneously with the CHMSL or at a time when the turn signals are flashing. In addition, manufacturers, distributors, dealers, and motor vehicle repair businesses are subject to 108(a)(2)(A) of the Safety Act, which states: 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative ... 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 ....' It is conceivable that your product, when placed on a vehicle's rear window, could 'render inoperative' the vehicle's ability to comply with FMVSS No. 108 and FMVSS No. 111. Persons in the aforementioned categories that install your product must ensure that such installation does not render inoperative the safety protection provided by the applicable standards. Specifically, your product should be mounted so that it does not interfere with the CHMSL or turn signal lamps nor block the field-of-view required by FMVSS No. 111. The 'render inoperative' prohibition of 108(a)(2)(A) does not apply to the actions of vehicle owners in adding to or otherwise modifying their vehicles or items of motor vehicle equipment. Thus, if your product were placed on a rear window by the vehicle owner, then the render inoperative provision would not apply. Nevertheless, in the interest of safety, you should ensure that your product does not adversely affect a vehicle's rear lamps or rearward visibility. We are unable to advise you as to whether the laws of any State address this topic. You should consult the American Association of Motor Vehicle Administrators for an opinion. Its address is 4600 Wilson Boulevard, Arlington, Va. 22203. I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam2027OpenMr. Jerry Toner, Consultant, Transportation, Traffic & Safety, Superintendent of Public Instruction, Old Capitol Bldg., Olympia, WA 98504; Mr. Jerry Toner Consultant Transportation Traffic & Safety Superintendent of Public Instruction Old Capitol Bldg. Olympia WA 98504; Dear Mr. Toner: This is in reply to your letter of July 15, 1975, to Mr. J. E. Leysat of this agency asking whether the State of Washington's proposed school bus light warning system conflicts with S4.1.4(b)(ii) of Federal Motor Vehicle Safety Standard No. 108.; That section requires an eight lamp signal system to be wired 'so tha the amber signal lamps are activated only by manual or foot operation, and if activated, are automatically deactivated and red signal lamps automatically activated when the bus entrance door is opened.' Under the system Washington proposes, when a school bus stops, a 'stop paddle sign' is extended by the operator, activating 'a switching system which will terminate the yellow flashing lights and start the red flashing lights,' before the door is opened.; Under the system you describe, the termination of the yellow lamps an activation of the red ones is dependent upon the operator extending the stop paddle sign. Should the operator forget to extend the sign, it does not appear that the system required by S4.1.4 would operate automatically when the door is opened. We therefore conclude that in order to meet S4.1.4 your school buses must be equipped with an override switch that would deactivate the amber lamps and activate the red ones when the door is opened, in the event that the stop paddle sign has not been extended.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam5648OpenMs. Alison Vredenburgh Vice President Research and Development Error Analysis, Inc. Suite 205 5811 Amaya Drive La Mesa, CA 91942-4156; Ms. Alison Vredenburgh Vice President Research and Development Error Analysis Inc. Suite 205 5811 Amaya Drive La Mesa CA 91942-4156; "Dear Ms. Vredenburgh: This is in reply to your letter of September 18 1995, to Kenneth Hardie of this agency, with respect to the Motorcycle Conspicuity Enhancement System (the 'System') described in your letter. You understand 'that this system may only be used during daylight hours and may not affect the headlight', and you ask if there are any other regulations of which you should be aware. We understand that the System is still under development, and that the intent is to offer it both as original and aftermarket equipment. Two Systems will be tested, at a flash rate of 60 to 80 per minute, one at an intensity of 35,000 candlepower, and the other at 50,000 candlepower. One System will have three bulbs, and another, four. Each System will be activated when the headlamp is on. We note that motorcycle headlamps are wired to be activated when the ignition is on because many States require that headlamps be operating at all times. As you know, each motorcycle must be manufactured and certified to conform to all applicable Federal motor vehicle safety standards, including Standard No. 108 Lamps, Reflective Devices, and Associated Equipment. Standard No. 108 prescribes no requirements for supplemental equipment such as the System. However, additional lighting equipment may not be installed by the manufacturer or dealer before sale if the supplemental equipment impairs the effectiveness of lighting equipment required by Standard No. 108 (paragraph S5.1.3). You are therefore correct when you say that the System 'may not affect the headlamp.' One way in which the System could impair the effectiveness of the headlamp is if it continued to operate at a time when the headlamp is required to provide sufficient illumination of the roadway (as you recognize in your comment that 'the system may only be used during daylight hours'). You have not described the method by which the System will be deactivated. We believe that this should not be a manual operation, left to the discretion of the motorcycle operator. In establishing the specifications that allow optional installation of modulating headlamp systems for improving the conspicuity of motorcycles, this agency requires that they be equipped with a sensor that will deactivate the modulation when a certain low ambient light level is reached. Also, the modulation rate is regulated to prevent seizures in susceptible individuals. I enclose a copy of paragraph S5.6 of Standard No. 108 which discusses these light levels. The System must also not impair the effectiveness of the motorcycle's front turn signals. That is to say, it must not mask the signal or detract from its detectability by oncoming drivers. Whether this might occur will depend upon the color and brightness of the System and its proximity to the turn signal lamp. If a motorcycle manufacturer is satisfied that the installation of the System on its product would be permissible under S5.1.3, then it may certify that the motorcycle conforms to all applicable Federal motor vehicle safety standards. NHTSA will not question a determination of non-impairment unless it appears to be clearly erroneous. Satisfaction of Federal new vehicle requirements means that the System is acceptable for sale in the aftermarket under Federal regulations. However, supplementary lighting equipment, whether original or aftermarket, that is not specifically covered by Standard No. 108 remains subject to regulation by the States. We note that many States have vehicle equipment and use regulations regarding auxiliary amber flashing lamps, Many States also prohibit blue as a color for lamps, reserving it for police, fire, and emergency vehicles. We are unable to advise you on the specifics of State laws, and urge you to consult the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. If you have any further questions, you may refer them to Taylor Vinson of this Office (202-366-5263). Sincerely, Samuel J. Dubbin Chief Counsel"; |
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ID: aiam2477OpenMr. Joseph E. Papelian, Department of Police, Detroit, MI 48226; Mr. Joseph E. Papelian Department of Police Detroit MI 48226; Dear Mr. Papelian: This is in response to your letter of November 9, 1976, asking whethe Federal regulations permit manufacturers to equip police vehicles with 'push bumpers' and with bullet-proof shields located between the front and rear seating compartments.; Standard No. 215, *Exterior Protection*, establishes requirements fo the impact resistance and the configuration of front and rear vehicle surfaces of passenger cars. This standard does not prohibit 'push bumpers' and manufacturers are free to equip passenger cars with any bumper design they choose as long as the requirements of Standard No. 215 are met.; Standard No. 205, *Glazing Materials*, specifies requirements fo glazing for use in motor vehicles, including the permissible locations for the various types of glazing. The standard permits bullet-resistant glazing to be used anywhere in a motor vehicle, provided such glazing meets specified performance requirements. Therefore, vehicle manufacturers are permitted to equip vehicles with the bullet-proof shields mentioned in your letter if such shields are constructed with glazing that conforms to the requirements in Standard No. 205.; You also asked whether the police department or a business coul install the equipment in question. If the equipment is installed after the first sale of the vehicle for purposes other than resale, the Federal safety standards would no longer be applicable under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S 1397(b)(1). However, S 108(a)(2)(A) prohibits, with one exception, manufacturers, distributors, dealers, and motor vehicle repair businesses from knowingly rendering inoperative a safety device or element of design that has been installed in compliance with a motor vehicle safety standard.; Therefore, whether or not a business could install the equipmen depends on the nature of the business. If the business is a 'motor vehicle repair business', it can only install the 'push bumpers' and shields if such installation does not knowingly render inoperative devices or elements of design installed in the vehicle in compliance with applicable safety standards. Section 108(a)(2)(A) defines 'motor vehicle repair business' as any person who holds himself out to the public as in the business of repairing motor vehicles or motor vehicle equipment for compensation.; I have enclosed copies of Standard No. 205 and Standard No. 215. I hav underscored the pertinent sections of Standard No. 205 (and the ANS Z26 standard incorporated by reference in Standard No. 205) for your information.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam4409OpenKarl F. Milde, Jr., P.C., Law Offices, RFD #8, Box 369, Union Valley Road, Mahopac, NY 10541; Karl F. Milde Jr. P.C. Law Offices RFD #8 Box 369 Union Valley Road Mahopac NY 10541; Dear Mr. Milde: This is in reply to your letter of October 2, 1987, with reference t an electronic circuit that would automatically activate a vehicle's hazard warning system when the vehicle is proceeding slowly, or has stopped in the roadway. You have asked whether such a system has been proposed before, or field tested, and whether Federal Motor Vehicle Safety Standard No. 108 would permit its installation on motor vehicles.; The traffic hazard that concerns you, especially that presented by vehicle that has stopped in the roadway without activation of either brakes or hazard warning system, is one that is familiar to many motorists. However, it appears that in actuality most motorists confronted with this hazard are able to react in time to avoid a rear end collision. Accident data available to the agency indicate that crashes of this nature are relatively rare. As you know, many States require activation of the hazard warning system at speeds less than 40 mph on the Interstate system. NHTSA has not proposed a system of this nature, nor has it field tested one. The agency has participated in research with deceleration warning systems, a similar though not identical concept, and concluded that safety benefits were insufficient to propose their adoption.; We see no Federal prohibition against installation of a circuit tha would activate the hazard warning system at a predetermined low rate of speed. Equipment that is not prescribed by the lighting standard is permissible as original equipment as long as it does not impair the effectiveness of equipment that Standard No. 108 does require. And modifications of vehicles in use by persons other than the vehicle owner are permissible as long as they do not render inoperative, in whole or in part, vehicle equipment necessary for compliance with a Federal motor vehicle safety standard. Nor are we aware of any State restrictions on the use of such a system, though you should consult the American Association of Motor Vehicle Administrators for a definitive answer. Its address is 1201 Connecticut Avenue, NW, Washington, DC 20036.; Sincerely, Erika Z. Jones, 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.