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: aiam0284OpenMr. William R. Graham, Bus and Truck Supply Co., 315 Continental Avenue, Dallas, TX 75207; Mr. William R. Graham Bus and Truck Supply Co. 315 Continental Avenue Dallas TX 75207; Dear Mr. Graham: This is in reply to your letter of December 30, 1970, requesting a interpretation of Motor Vehicle Safety Standard No. 205, 'Glazing Materials,' as it applies to the forward-facing window above the windshield of a particular bus, a picture of which you enclosed.; Because the window in question is a forward-facing window, we canno conclude that it is an 'opening in the roof' under the standard. We apologize for the inconvenience caused by any implication to the contrary that you may have been given on your visit here.; Based upon the picture submitted, and your statement that the windo 'is not adjacent to passenger seating,' we conclude that this location is one that is not specifically designated by the standard. As such, the use of AS2 glazing, which you indicated you plan to use, or alternatively AS1, AS3, AS10, or AS11 glazing, would be appropriate.; If you have further questions, we will be happy to answer them for you. Sincerely, Rodolfo A. Diaz, Acting Associate Administrator, Moto Vehicle Programs; |
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ID: aiam2313OpenMr. Charles N. Eblin, Service Director, City of Marion, 685 Delaware Avenue, Marion, OH 43302; Mr. Charles N. Eblin Service Director City of Marion 685 Delaware Avenue Marion OH 43302; Dear Mr. Eblin: This responds to your May 6, 1976, request for permission to remove th brake system from two trucks that were manufactured with brake systems conforming to the requirements of Standard No. 121, *Air Brake Systems*.; From the description of the problems you have encountered with th vehicles, I assume that you do not intend to remove the entire brake system, but only one or more antilock systems installed in satisfaction of the 'no lockup' requirement of S5.3.1 of Standard No. 121. Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S 1397(a)(2)(A)) prohibits, with one exception, knowing disconnection of the antilock system by a manufacturer, distributor, dealer, or repair business. Your dealer's refusal to remove the devices is probably based on this prohibition.; A person that does not fall into these categories is not prohibite from disconnection of the systems. Other State or Federal requirements, such as those of the Bureau of Motor Carrier Safety for operation in interstate commerce, may prohibit disconnection. In any case, the NHTSA urges that you not disconnect safety devices without consulting the vehicle manufacturer with regard to the safety configuration of the vehicle.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2186OpenMr. David Warfield, Box 1207, Easton, Maryland 21601; Mr. David Warfield Box 1207 Easton Maryland 21601; Dear Mr. Warfield: This is in response to your January 21, 1976, request for a interpretation of Federal Motor Vehicle Safety Standard No. 117, *Retreaded Pneumatic Tires*.; You asked whether a retreaded tire may be manufactured with a casin from which the original manufacturer's tire identification number (required by 49 CFR Part 574 and Standard No. 109) has been buffed off, provided the original DOT symbol remains. The answer to your question is yes. The only items of information that are required to be retained from the original casing are the following:; >>>(a) the symbol DOT, (b) the size of the tire, and (c) the actual number of plies or ply rating.<<< A retreaded tire must also, of course, be labeled with the DOT-R symbo and with the retreader's tire identification number, pursuant S6.1 of Standard No. 117 and 49 CFR Part 574.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5643OpenMr. Eric D. Swanger Engineering Manager Specialty Manufacturing Co. P.O. Box 790 10200 Pineville Road Pineville, NC 28134; Mr. Eric D. Swanger Engineering Manager Specialty Manufacturing Co. P.O. Box 790 10200 Pineville Road Pineville NC 28134; Dear Mr. Swanger: This responds to your request for an interpretatio of the conspicuity requirements in Federal Motor Vehicle Safety Standard No. 131, School Bus Pedestrian Safety Devices. According to your letter, a State has requested that you use light-emitting diodes (LEDs) to outline the word 'STOP' on the stop arm blade. That State believes such lighting would increase the sign's conspicuity in certain weather conditions. In your letter and in an October 2, 1995, telephone conversation with Mr. Paul Atelsek of my staff, you expressed your concerns that using LEDs on stop signal arms may cause confusion and asked whether they are permitted. You raised three specific issues relating to viewing angles, legibility from certain distances, and inconsistencies among various jurisdictions. The short answer to your question is that the LEDs could comply with our standard, but only under certain conditions. As you are aware, S5.3 Conspicuity states that 'The stop signal arm shall comply with either S5.3.1 or S5.3.2, or both.' Either method of providing conspicuity is by itself sufficient. I will discuss how the presence of LEDs relates to each of these options and then address your specific questions below. Section S5.3.1 sets forth the requirements of the reflectorization option, stating that ' t he entire surface of both sides of the stop signal arm shall be reflectorized with type III retroreflectorized material . . . .' LEDs would appear on the surface of the arm but could not, as far as we know, qualify as type III retroreflectorized material. Therefore, LEDs are not permissible when compliance depends upon the reflectorization option. Section S5.3.2, which references S6.2, sets forth requirements addressing flashing lamps. Section S6.2 specifies the lamp's color, flash rate, and on- off time. These rather specific requirements reflect the importance of consistency in any signage or labeling requirement. However, we do not see anything intrinsic about LEDs that would preclude their use in stop signal arms with flashing lamps. As long as the familiar flashing lamps are used, we do not believe that interstate confusion would result from the addition of LEDs. Note that we do not consider the use of LEDs as an 'optional' method of compliance with S5.3.2, because the LEDs would not be centered on the vertical centerline at the top and bottom of the stop arm. You expressed concerns in your letter about the narrow viewing angle of LEDs compared to incandescent lights, and about the legibility of the LEDs at a distance. Since the LEDs would be used as a supplement to a standard method of compliance (i.e., flashing lamps), a diminished viewing angle is not important. We assume manufacturer's quality control practices would prevent uneven viewing angles from LED to LED within a given stop arm. While your concerns about the legibility of the word 'STOP' at a distance are important, they do not seem to relate to the presence or absence of the LEDs unless the LEDs reduce the legibility of the word. If you have data indicating that the size or spacing of the letters needs to be increased to achieve greater legibility at a distance, you may petition NHTSA to revise the standard. I want to raise one potential safety issue, in case you receive a request to design an LED-equipped stop signal with flashing lamps. Certain arrangements of LEDs might affect compliance by impairing the effectiveness of the stop signal arm's flashing lamp. Very closely spaced red LEDs could enhance the readability of the letters in poor visibility conditions. On the other hand, red LEDs spaced every few centimeters around the outline of the 15 cm high letters could appear as a random field of lights (like a Christmas tree), distracting the observer and resulting in diminished readability. Similarly, different flash rates or on-off speeds from installed incandescent lamps might detract from readability by creating a distracting double-flash effect, as you suggest. Whether a particular LED-equipped stop signal arm complies with Standard No. 131 is a matter that can be determined only in the context of an enforcement proceeding. I hope this information is helpful. If you have any further questions, please feel free to contact Paul Atelsek at this address or by telephone at (202) 366-2992. Sincerely, Samuel J. Dubbin Chief Counsel; |
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ID: aiam4951OpenMr. Cliff Chuang, President Prospects Corporation 2790 Upper Ridge Dr. #2 Rochester Hills, MI 48307; Mr. Cliff Chuang President Prospects Corporation 2790 Upper Ridge Dr. #2 Rochester Hills MI 48307; "Dear Mr. Chuang: This responds to your request for an interpretatio of Federal Motor Vehicle Safety Standard No. 118 Power Windows (49 CFR 571.118). As you noted in your letter, the agency has published a final rule amending Standard No. 118 in the April 16, 1991, edition of the Federal Register (56 FR 15290). You requested clarification of certain requirements in that final rule. The agency has received several petitions for reconsideration of the final rule amending Standard No. 118. One such petition is from your company. The agency is currently reviewing the merits of each petition. The agency will issue a notice in the Federal Register granting and/or denying the petitions. In that notice, the agency will also address the concerns raised in your request for an interpretation of Standard No. 118. Please let us know if you have any questions about the issues raised in your letter after our response to the petitions for reconsideration has been published and you have had the opportunity to review it. If you need more information on this subject, please feel free to contact Dorothy Nakama of my staff at this address, or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0441OpenMr. Yasunobu Mitoya, Project Manager, Designing Division, Toyo Kogyo Co., Ltd., 6047 Fuchu-Machi, Aki-Gun, Hiroshima, Japan; Mr. Yasunobu Mitoya Project Manager Designing Division Toyo Kogyo Co. Ltd. 6047 Fuchu-Machi Aki-Gun Hiroshima Japan; Dear Mr. Mitoya: This is in response to your letter concerning 'Parts Subject to MVS No. 302,' your reference No. P-71-10, dated June 21, 1971. In paragraph A of your letter you list several vehicle components and ask whether, because the size of the component is small when compared to the specified sample size of S5.2, the component must still meet the requirements of the standard. If so, you ask which components, based upon pictures of the vehicle that you enclosed, are subject to the standard.; The answer to your question is yes. Whether a particular component mus meet the requirements of the standard does not depend upon its size, but upon whether it is included within the language of S4.1. If a particular component is smaller than the sample size specified in S5.2.1, it may be tested using the heat resistant wires described in S5.1.3.; With regard to whether the components you list are subject to th standard, in our answer we have combined those you listed in question A as well as in question B. Our answers are based solely upon the pictures you submitted and not an actual vehicle, and we cannot therefore be specific in all instances. While none of the components you list is specifically referred to in S4.1, some of the components appear to closely resemble or to be merely different descriptions of items that are enumerated. If so, they are subject to the standard. These are the parcel shelf and scarf plate. Seaming welt and seaming rubber should be considered as part of the component to which it is attached and for which it provides a seam.; Whether the other items you list are subject to the standard depend upon whether they are 'other interior materials . . . designed to absorb energy on contact by occupants in the event of a crash.' The components that you list that may fall within this category are the head restraint adjuster knob, radio, lighter, choke and other knobs, combination switch knob, steering wheel, transmission control lever knob, door latch release cover, window control knob, seat slide knob, reclining knuckle cover, room lamp, interior rear view mirror, meter case, glove compartment door, decoration plate of radio and clock, steering column cover, console, venitilation (sic) (ducts), transmission control lever boot, heater, steering wheel hub, and air conditioner. Items that we can determine would not be covered under this language would be the pedal pads and the wiring beneath the instrument panel.; If you have additional questions, please write to us. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam5213OpenMr. James G. O'Neill 107 Newcastle Lane Willingboro, NJ 08046; Mr. James G. O'Neill 107 Newcastle Lane Willingboro NJ 08046; "Dear Mr. O'Neill: This responds to your letter asking about th Federal requirements that would apply to a plastic toy holder you wish to manufacture for child car seats. You indicate on a sketch provided with your letter that the toy holder would fit into a mounting bracket that is attached by screws to the car seat. By way of background information, the National Traffic and Motor Vehicle Safety Act ('Safety Act,' 15 U.S.C. 1392) authorizes NHTSA to issue safety standards for new motor vehicles and new items of motor vehicle equipment. NHTSA does not, however, approve or certify any vehicles or items of equipment. Instead, the Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. The agency periodically tests vehicles and items of equipment for compliance with the standards. Under the authority of the Safety Act, NHTSA issued Standard 213, Child Restraint Systems, which specifies requirements for new child seats used in motor vehicles and aircraft. A new child seat that is sold with your toy holder attached to must be certified by the seat manufacturer as meeting Standard 213. NHTSA would determine the compliance of the new child seat with Standard 213 by, among other things, testing it with a test dummy in a 30 mph dynamic test. Based on the information in your letter, it appears that a new child seat with your toy holder might not meet Standard 213. S5.2.2.2 of the standard specifies, among other things, that each child seat must not have any fixed or movable surface (other than restraining devices) in front of the test dummy restrained in the child seat. This requirement is to prevent items that could injure a child in a crash from being installed where they could be impacted by a child. While your sketch is unclear, it appears that the toy holder could be located in front of the dummy. If so, the toy holder could be impacted by a child in a crash. Also, a new child seat with the toy holder attached to it might not comply with S5.2.4 of Standard 213. S5.2.4 requires any rigid part of the child seat that can be contacted by the head or torso of the dummy in the dynamic test to have a height of not more than 3/8 inch above any adjacent surface, and have no exposed edge with a radius of less than 1/4 inch. A restrained dummy could impact a toy holder attached to the side of the child seat if the dummy twisted during the dynamic test. If your product will be sold to consumers as an aftermarket item, Standard 213 does not apply to it, since the standard only applies to new child seats and not to accessory items. There is no Federal motor vehicle safety standard that applies to the toy holder. I note, however, that there are other Federal requirements that indirectly affect the manufacture and sale of your product. Under the Safety Act, your product is considered to be an item of motor vehicle equipment. Manufacturers of motor vehicles and motor vehicle equipment are subject to the defect provisions of the Safety Act. In the event that you or NHTSA determines that your toy holder contains a safety-related defect, you would be responsible for notifying purchasers of the defective equipment and remedying the problem free of charge. If data indicated that a child seat accessory exposed occupants to an unreasonable risk of injury, such as a toy holder installed where it was impacted by children, the agency might conduct a defect investigation which could lead to a safety recall. 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 appears unlikely that your product would be attached to a child seat by persons in the aforementioned categories. However, if such a person were to attach the toy holder, he or she could violate 108(a)(2)(A) if the child seat's compliance with S5.2.2.2 and S5.2.4 were compromised. Section 109 of the Safety Act specifies a civil penalty of up to $1,000 for each violation of 108. 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, child seat owners could attach the toy holder without having to meet Standard 213. We reiterate, however, that in the interest of safety, a plastic toy holder should not be installed where a child could impact it in a crash. I hope this information is helpful. I have enclosed an information sheet that provides additional information for new manufacturers of motor vehicles and motor vehicle equipment. If you have further questions, please contact Deirdre Fujita of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam0011OpenMr. Bill Lewandoski Account Manager Kelsey Products Division 38481 Huron River Drive Romulus, MI 48174; Mr. Bill Lewandoski Account Manager Kelsey Products Division 38481 Huron River Drive Romulus MI 48174; Dear Mr. Lewandoski: This responds to your letter of April 30, l99l, t Taylor Vinson of this Office with respect to the regulation of trailer stop lamp activation by Standard No. 108. You have enclosed a photocopy of literature on the Tekonsha Voyager electronic brake control. This system incorporates a manual override side bar that manually activates the trailer brakes without a corresponding activation of the trailer stop lamps. The reason for this is the manufacturer's view that 'STOPPING IS NOT THE INTENT. BY NOT DRIVING THE STOPLIGHTS DURING MANUAL ACTIVATION, THE VOYAGER ELIMINATES FALSE BRAKE LIGHT SIGNALS . . . .' The literature carries the notation that 'THE VOYAGER AND VOYAGER XP MEET NATIONAL HIGHWAY TRANSPORTATION (sic) SAFETY ADMINISTRATION (N.H.T.S.A.) REGULATIONS REGARDING TOW VEHICLE/TRAILER LIGHT APPLICATION.' You have asked whether Standard No. 108 permits application of the trailer brakes without activation of the towing vehicle/trailer stop lamps. It does not. Tekonsha misunderstands the function of a stop lamp. A stop lamp not only indicates the intent of the driver to stop, but also the intent of the driver 'to diminish speed by braking.' (see the definition of 'stop lamp' in SAE Standard J568c, Stop Lamps, August l970, incorporated by reference in Standard No. 108). Paragraph S5.5.4 of Standard No. 108 requires that 'The stop lamps on each vehicle shall be activated upon application of the service brakes.' The Voyager electronic control applies the service brakes to diminish vehicle speed, and therefore the stop lamps are required to be activated. The installation of the Voyager by a manufacturer or dealer before the initial sale of a trailer would therefore appear to be a violation of Standard No. 108 since its operation would create a noncompliance with the standard. As an aftermarket device, it is subject to the 'render inoperative' prohibition of l5 U.S.C. 1397(a)(2)(A). Any manufacturer, distributor, dealer or motor vehicle repair business installing the device after the trailer's initial sale is, in effect, rendering the trailer's stop lamps inoperative when the device is used. Civil penalties are provided for with respect to violations of either Standard No. 108, or section 1397(a)(2)(A). The statement as to compliance with NHTSA regulations is wrong. We appreciate your bringing this matter to our attention. I am forwarding a copy of your letter to our Office of Vehicle Safety Compliance for such further action as it deems appropriate. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam4052OpenMr. Russell Thatcher, Director Mobility Assistance Program, Executive Office of Transportation and Construction, Commonwealth of Massachusetts, 10 Park Plaza, Room 3510, Boston, MA 02116- 3969; Mr. Russell Thatcher Director Mobility Assistance Program Executive Office of Transportation and Construction Commonwealth of Massachusetts 10 Park Plaza Room 3510 Boston MA 02116- 3969; Dear Mr. Thatcher: Thank you for your letter of October 3, 1986, to NHTSA Regiona Administrator Jack Connors requesting an interpretation of Standard No. 210, *Seat Belt Assembly Anchorages*. Your letter was referred to my office for reply.; You explained that you are in the process of buying a number of van which will be outfitted with Republic Seating Corporation's Model D117 seats. You stated that questions have been raised about whether the safety belt placement on those seats complies with our standard. You enclosed a quarter-scale diagram of the seat in question showing the location of the safety belts and asked our opinion about whether the safety belt placement complies with our standard.; Under the National Traffic and Motor Vehicle Safety Act, which thi agency enforces, it is the responsibility of a vehicle manufacturer to certify that its products comply with the requirements of our standards. This agency does not have the authority to approve a manufacturer's design plans. We can offer our opinion, but it is the manufacturer's obligation to ensure that the finished vehicle complies with all of the applicable standards.; The standard which affects the mounting angle for safety belts i Standard No. 210, *Seat Belt Assembly Anchorages*. The drawing enclosed with your letters shows that the lap safety belt anchorage for this seat is installed on the frame of the seat. S4.3.1.3 of the standard provides:; >>>In an installation in which the seat belt anchorage is on the sea structure, the line from the seating reference point to the nearest contact point of the belt with the hardware attaching it to the anchorage shall extend forward from that contact point at an angle with the horizontal of not less than 20 degrees and not more than 75 degrees.<<<; According to the drawing enclosed with your letter, the line from th seating reference point to the nearest contact point of the safety belt, on the outboard side of the seat, with the hardware attaching it to the anchorage is 75 degrees. If the outboard portion of the safety belt is installed in a completed vehicle in the location shown in the drawing it would meet the requirement of S4.3.1.3, since its mounting angle is not more than 75 degrees.; We cannot offer an opinion as to whether the inboard portion of th safety belt would comply with S4.3.1.3, since the mounting angle for that portion of the safety belt is not depicted in the drawing. I want to emphasize again, that this letter represents the opinion of the agency based on the facts you have presented. It is a manufacturer's responsibility under the Vehicle Safety Act to certify that its completed vehicle complies with our standard.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3797OpenJohn H. Schmidt, P.E., Certification Supervisor, Harley- Davidson Motor Co., Inc., 3700 W. Juneau Avenue, P.O. Box 653, Milwaukee, WI 53201; John H. Schmidt P.E. Certification Supervisor Harley- Davidson Motor Co. Inc. 3700 W. Juneau Avenue P.O. Box 653 Milwaukee WI 53201; Dear Mr. Schmidt: This responds to your February 6, 1984 letter to Roger Fairchild o this office, in which you asked whether your company may include on vehicle certification labels gross vehicle weight rating and gross axle weight rating information expressed in kilograms. The metric units would be used in addition to information expressed in pounds, with the English units appearing first on the label and the metric units following in parenthesis. Our certification regulations (49 CFR Part 567) provide that this information is to be specified in pounds.; The inclusion of metric weight ratings in addition to the English unit specified in our regulation (with the English units appearing first) has previously been approved in an agency interpretation letter, a copy of which is enclosed. Therefore, your proposed certification labels are authorized under the certification regulations.; 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.