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: 1982-2.30OpenDATE: 08/02/82 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Roberts Motor Company TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of July 16, 1982, asking for an interpretation of Motor Vehicle Safety Standard No. 108. You enclose photos of a 1982 Kenworth truck which has two pairs of front turn signal lamps: one set (incorporating a side reflector) mounted 58 1/2 inches above the road surface and which are 83 inches apart; the other, mounted approximately 81 1/2 inches above the road surface and which are 110 inches apart. You have asked whether the vehicle would comply if the lower mounted set were removed and an amber reflex reflector placed on each side of the fender as far forward as practicable. The answer is yes. The mounting height of 81 1/2 inches does not exceed the limit of 83 inches imposed by Table II of Standard No. 108. In addition, the lamps appear to meet the two further requirements that they be located as far apart as practicable and at the same height. Sincerely, ATTACH. July 16, 1982 Administrator -- National Highway Traffic Safety Administration, Department of Transportation Subject: Federal Motor Vehicle Safety Standard Number 108 Lamps, Reflective Devices and Associated Equipment Gentlemen: Enclosed please find two photographs of a 1982 Kenworth, Model W900. You will note from the photographs that two sets of turn signals are on the vehicle, one set on the hood and another set on the bottom of the mirror brackets. On the vehicle shown, which is typical of the Model, the center of the fender mounted signals are approximately 58 1/2" above the road surface and approximately 83" apart. The center of the mirror mounted turn signals are approximately 81 1/2" above the road surface and approximately 110" apart. Our question concerns Federal Motor Vehicle Safety Standard Number 108(571.108), specifically, Table II, "Location of Required Equipment", "Turn Signal Lamps". Considering the dimensions above, would the vehicle be in conformance with the Standard if only the mirror mounted turn signals were installed on the vehicle and an amber reflex reflector placed on each side of the fender as far forward as practicable? We would appreciate your consideration and reply to this matter at your earliest opportunity. Yours truly, Ronald E. DeVolder -- Vice President enclosures (Graphics omitted) |
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ID: 1982-2.34OpenDATE: 08/10/82 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Dwight Hicks Jr. TITLE: FMVSS INTERPRETATION TEXT:
Dwight Hicks, Jr. 1208 Balthis Drive, Apt. B Gastonia, NC 28052
Dear Mr. Hicks:
This responds to your recent inquiry regarding the applicability of Federal Motor Vehicle Safety Standard No. 125 to a warning device you plan to manufacture. That device is a rectangular sign with a base. The sign has the word "HELP" in reflective letters on its surface and is designed to be illuminated by a cyalume light stick attached to the top of the sign. The sign is intended either to be mounted on a vehicle or to be erected on the road.
Section 3 of Standard 125 provides that the standard does not apply to warning devices which have "self-contained energy sources" used to illuminate the device. Although the cyalume light stick used in your device would not provide a very bright source of illumination, the light stick would constitute such an energy source. Therefore, the warning device you describe does not appear to be subject to that standard. This conclusion applies only to the device as described in your submission to us. Subsequent design modifications regarding this energy source could change the agency's conclusion. With regard to your question as to a recommended color to be used in your sign, section 5.3, of Standard 125 specifies the colors the agency has determined to be most appropriate for use in warning devices. We recommend that you use those colors.
Page 3 of your submission to us includes what appears to be instructions to users of your device. Those instructions state that failure to attach the light sticks to the sign would be a violation of our standards. Neither Standard 125 nor the statute under which it was issued applies to users of warning devices. Instead, they apply to the manufacturers, distributors and sellers of warning devices. These parties are prohibited from manufacturing or selling warning devices which, although subject to the standard, do not comply with our standard. Therefore, we urge deleting the last sentence of the first numbered paragraph on page 3. If you have further questions on this matter, feel free to contact us. Sincerely, Original Signed By Frank Berndt Chief Counsel |
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ID: nht87-1.79OpenTYPE: INTERPRETATION-NHTSA DATE: 05/25/87 FROM: AUTHOR UNAVAILABLE; EriKa Z. Jones; NHTSA TO: Mr. Thomas L. Long TITLE: FMVSS INTERPRETATION TEXT: Mr. Thomas L. Long Vice-President R & D Think, Inc. P.O. Box 414 Smyrna, TN; 37167 Dear Mr. Long: This is in reply to your letter of August 20, 1987, to Taylor Vinson of this office. You have enclosed a decal intended to be affixed "on the outside of the rear window of an automobile, directly in front of the high mounted stop light." You have asked about the relationship of the decal to Federal Motor Vehicle Safety Standard No. 108. Center highmounted stoplamps are required to be designed so that light outlet (candela) may be measured at 13 individual test points, at a distance of not less than 10 feet. With the decal applied to the rear window, it is possible that the requisite minimum or maximum candela specified by Standard No. 103 could not be met at all of the test points. Further, the effective luminous area of the lamp must be not less than 4 1/2 square inches, and while the decal would not be applied to the lens, nevertheless, the lens area when viewed from behind could be effectively reduced. Because a vehicle must meet Standard No. 108 at the time of its initial sale, the vehicle could be delivered to its purchase: with the decal attached only if the vehicle continued to meet the light output and effective luminous area requirements. Even if a vehicle could not be delivered with the decal attached, nothing in Standard No. 108 or the National Traffic and Motor Vehicle Safety Act prohibits a vehicle owner from applying the decal to his own vehicle, or from taking any other action that might affect the compliance of his vehicle with any of the Federal motor vehicle safety standards. The Act does forbid other persons from such actions, so that after a vehicle is sold, the dealer (or a motor vehicle repair business) could still be prohibited from applying the decal. Regulation of a vehicle in use is a matter of the laws of the States where vehicles are registered and operated. Even though Federal law does not prohibit an owner from applying the decal, a State law might. For advice on State laws, you should write the American Association of Motor Vehicle Administrators, 1201 Connecticut Ave. N.W., Washington, D.C. 20036. Sincerely, Erika Z. Jones Chief Council |
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ID: nht87-1.9OpenTYPE: INTERPRETATION-NHTSA DATE: 01/11/87 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: Donald J. Audia TITLE: FMVSS INTERPRETATION TEXT: Dear Mr. Audia: This is in reply to your letter of December 12, 1986, to Taylor Vinson of this Office asking about the permissibility of manufacturing an aftermarket center highmounted stop lamp utilizing the colors yellow and orange, in addition to red, to signify "t he varying stages of a stopping car." Under Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment only the color red is permitted for original equipment center highmounted stop lamps, and for those aftermarket lamps manufactured to replace them. The se lamps are generally found on passenger cars manufactured on and after September 1, 1985. Your planned device could not be manufactured and sold for this segment of the aftermarket since it does not conform to Standard No. 108. Further, a dealer, distr ibutor, or motor vehicle repair business could not legally remove an original equipment center highmounted stop lamp and install your device. However, there is no Federal restriction on sale and installation of your device on passenger cars manufactured before September 1, 1985. The device would then be subject to the laws of any State where it would be sold or used. We regret that we are unable to advise you on these laws. If you have any further questions we would be happy to answer them. Sincerely, Erika Z. Jones Chief Counsel December 12, 1986 Mr. Taylor Vinson Legal Dept. N.H.T.S.A. Department of Transportation 400 Seventh Street, S.W. Washington, D. C. 20590
Dear Mr. Vinson: My point of reference concerns the "third light" or High-Mounted Stop Lamps. I would like your opinion or your advice with regard to the aforementioned device. Specifically, am I permitted to utilize three different colors, (i.e. yellow, orange, red) to signify, if you will, the varying stages of a stopping car? I will attempt to infiltrate the "after market" and not try to change or enact any new versions unless my innovation is accepted universally. I ask that you please respond at your earliest convenience. Your response will enable me to continue my research and development. Enclosed please find my interpretation of the High-Mounted Stop Lamp. Thank you sincerely for your time and consideration. Respectfully submitted, Donald J. Audia |
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ID: nht87-2.24OpenTYPE: INTERPRETATION-NHTSA DATE: 06/26/87 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: The Honorable Bill Schuette TITLE: FMVSS INTERPRETATION TEXT: The Honorable Bill Schuette U.S. House of Representatives P.O. BOX 631 Midland, MI 48640 Dear Mr. Schuette: Thank you for your June 4, 1987, letter on behalf of your constituent, Mr. Dale Lighthill of Owosso. Mr. Lighthill owns a semi-trailer which he has converted into a travel home. He wishes to know whether there is any law which prohibits him from carrying persons in his travel trailer. Our agency is responsible for promulgating safety standards for the manufacture and sale of new motor vehicles. We have no jurisdiction over the use of motor vehicles and thus have no regulation prohibiting Mr. Lighthill from carrying people in his trave l home trailer. However, many states have enacted provisions in their vehicle codes for occupying moving trailers. Some states prohibit persons from occupying a moving trailer or operating a motor vehicle which is towing an occupied trailer, and some per mit occupying a moving trailer only under certain circumstances. I am certain that the officials of the states your constituent plans to visit will be happy to provide information on their laws for transporting persons in moving trailers. In addition, Mr . Lighthill night find it helpful to contact the American Association of Motor Vehicle Administrators (AAMVA) for general information on state requirements. The AAMVA may be reached at: Suite 910, 1201 Connecticut Avenue, N.W., Washington, D.C., 20036. T elephone: (202) 296-1955. Thank you for contacting our office. Please contact me if you or your constituent have any questions. Sincerely, Erika Z. Jones Chief Counsel
Erika Jones Chief Counsel NHTSA 400 7th Street, SW Room 5219 Washington, D.C. 20590 Dear Erika: I am writing with a request from my constituent, Dale Lighthill, of Owosso, Michigan. Mr. Lighthill owns a semi-trailer which has been converted into a travel home. He would like to know if there are any laws prohibiting carrying someone in the trailer s ection of this travel home anywhere in the continental U.S. I would appreciate it if you could research this question and advise me at my Midland District Office of your findings. Thank you very much for your time and attention to this matter. Sincerely, Bill Schuette Member of Congress |
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ID: 86-6.5OpenTYPE: INTERPRETATION-NHTSA DATE: 12/05/86 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: no addressee TITLE: FMVSS INTERPRETATION TEXT:
This is in reply to your letter of September 12, 1986, to the National Highway Traffic Safety Administration, and your letter to me of november 13, asking for our comments on four new motor vehicle lighting devices.
The first device performs a combination of two functions. It consists of three lamps serving as identification lamps and will meet all requirements of Standard No. 108 for such equipment. The three lamp cluster will also serve a auxiliary stop lamps (mistakenly referred to as a turn lamp in the November letter). The second device is a clearance lamp meeting requirements of Standard No. 108, which would also serve as an auxiliary stop lamp (also mistakenly referred to a a turn lamp in the November letter). The third device is described as a "tracking lamp" ( the diagram shows this to be the rear side marker lamp required by Standard No. 108) meeting all requirements for such; it will also serve as an auxiliary side turn signal indicator. The fourth device will serve as an intermediate side marker lamp, complying with Standard No. 108's requirements, but will also serve as an auxiliary side turn signal lamp. The devices are intended for use on wide trucks and trailers. In your opinion, the auxiliary functions will not "confuse or inhibit" the functioning of lighting equipment required by Standards No. 108.
With respect to the combination of lamp functions or truck and trailers, Standard No. 108, specifically paragraph S4.4, prohibits only the optical combination of clearance lamps with taillamps or identification lamps. These combinations do not exist in any of your four proposed designs. Under paragraph S4.1.3 supplemental lighting devices are permitted as long as they do not impair the effectiveness of lighting equipment required by Standard No. 108. You have concluded that there would be no impairment. Under the facts as presented in your letter, we have no reason to disagree with that conclusion.
We have noted your request that your letters be accorded confidential treatment because of proprietary commercial information, and your attorney's consent on your behalf that our interpretation may be made public provided that all information identifying you as the writer is deleted. We shall follow this procedure.
Sincerely, Erika Z. Jones Chief Counsel |
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ID: nht76-1.21OpenDATE: 12/14/76 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Universal Imports TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your November 5, 1976, letter concerning antique tires. You have asked whether it is permissible to import 6.70 x 15 tires, an original equipment size on several classic Mercedes-Benz, that are not marked in accordance with Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires. Standard No. 109 applies to "new pneumatic tires for use on passenger cars manufactured after 1948" (S2). The 6.70 x 15 tire size designation appears in Table I-A of Appendix A of the standard. While this tire may have been original equipment on several classic cars, it is also for use on passenger cars manufactured since 1948. As such, it is subject to all the requirements of Standard No. 109. Therefore, a 6.70 x 15 tire that is not marked according to the standard may not be imported into the United States. SINCERELY, Universal Imports Office of Chief Counsel National Highway Traffic Safety Association Attention: Frank Berndt, Acting Chief Counsel November 5, 1976 LETTER #7998 To date we are still anxiously awaiting reply to our letter No. 7725 dated September 13, regarding the sale of non-D.O.T. marked tires for off-road use. Since that time we have also come across a new problem regarding non-D.O.T. marked tires and this specifically is in regard to antique tires. We have recently had made available to use a line of Dunlop antique tires from their Vintage line. One particular tire, a 670 x 15 is of special interest to us as it is the original equipment size on several classic Mercedes. Regarding this problem, we have the following questions: 1. Can we legally import these tires at all? 2. Is there any provision for bringing in antique tires without D.O.T. marks for use on antique cars that are specifically for show, parades, etc.? 3. If there is no provision regarding the importation and sale of the above tires, what are our requirements as a vendor concerning the sale of these tires from both a retail and wholesale standpoint? Should you require any additional information or clarification, please contact me at the above address or telephone number. Looking forward to your early reply, we remain William G. Mathews, III Vice President |
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ID: nht76-1.24OpenDATE: 01/20/76 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Walt Robbins, Inc. COPYEE: FEDERAL TRADE COMMISSION TITLE: FMVSS INTERPRETATION TEXT: This is in response to your November 7, 1975, request for an interpretation of the labeling requirements of Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires -- Passenger Cars, as applied to the tire that you have described as a "Radial, Bias Ply Tire". On that date, a meeting was held with you, Mr. Al Duduk, and the following NHTSA personnel in attendance: Dr. E. H. Wallace, A. Y. Casanova, and Mark Schwimmer. At the meeting, our letter to you, dated November 3, 1975, was discussed and alternative forms of labeling for this tire were explored. You presented, in substance, the following four examples of sidewall labeling and inquired about their compliance with Standard No. 109: 1. "POLYANGLE" accompanied by "3 PLIES 2 POLYESTER 1 ARAMID" 2. "POLYANGLE" accompanied by "NOT A CONVENTIONAL RADIAL PLY TIRE" and "3 PLIES 2 POLYESTER BIAS PLIES 1 ARAMID RADIAL PLY" 3. "RADIAL/BIAS" accompanied by "NOT A CONVENTIONAL RADIAL PLY TIRE" and "3 PLIES 2 POLYESTER BIAS PLIES 1 ARAMID RADIAL PLY" 4. "RADIAL/BIAS" accompanied by "NOT TO BE USED WITH CONVENTIONAL RADIAL BELTED TIRES" and "3 PLIES 2 POLYESTER BIAS PLIES 1 ARAMID RADIAL PLY" Tires labeled according to your first example would be in compliance with the requirements of S4.3(g) of Standard No. 109. A strict interpretation of S4.3(g) would rule out the remaining examples because the word "radial" appears in all of them. However, the NHTSA recognizes that, with the development of new tire construction types, this section of the standard may not be adequate to serve its original purpose, to reduce the hazards associated with the mismatching of tires on a single vehicle. Accordingly, we are preparing to issue a notice of proposed rulemaking to amend the standard. For this reason and because the second, third, and fourth examples are in conformity with the spirit of S4.3(g), the NHTSA will, on an interim basis, consider tires so labeled to be in compliance. You may wish to consult with the Federal Trade Commission concerning the advertising of these tires. I would like to point out that S4.3(d) requires Kevlar, if used as a cord material in a tire, to be identified by its generic name on the tire's sidewall. The generic name of Kevlar, as established by the FTC pursuant to the Textile Fiber Product Identification Act (15 USC 70), is Aramid. Yours truly, ATTACH. |
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ID: nht76-1.7OpenDATE: 02/26/76 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Alaska Traffic Safety Bureau TITLE: FMVSS INTERPRETATION TEXT: This is in response to a request by Mr. William Hall, National Highway Traffic Safety Administration (NHTSA) Regional Administrator for Region X, for a review of Federal Motor Vehicle Safety Standard No. 104, Windshield Wiping and Washing Systems with special consideration of the comments of Mr. Robertson in his memorandum of November 24, 1975. It is the opinion of this agency that Standard No. 104 is appropriate for the State of Alaska. The essential feature of a wiping system, as far as safety is concerned, is its ability to clear a specific portion of the windshield. The number of wipers necessary to provide the driver with a sufficient field of view is immaterial so long as the minimum percentages of critical areas are washed and wiped. These areas are established in the standard and are determined by the angles from the driver's eye position over which the windshield must be kept clear to provide a proper field of view. While targets of driver attention and environmental conditions may differ from state to state, if the critical areas are clear, the field of view provided to the driver is sufficient. The 1976 Scirocco appears to provide the required field of view. The question therefore becomes whether the Federal standard on windshield wipers is intended to cover all aspects of wiping systems. If so, the situation is analogous to that presented to the court in Motorcycle Industry Council v. Younger, No. CIV S74-126 (E.D.Cal. 1974) which resulted in a holding that Standard No. 108 did preempt an inconsistent state regulation in the field of lighting requirements. The NHTSA has determined that the standard on windshield wiping systems, No. 104, is intended to leave the number of wipers to the discretion of the manufacturers. Under Thorpe v. Housing Authority of Durham, 393 U.S. 268 (1969), and Chrysler v. Tofany, 419 F2d 499, 511-12 (2d Cir, 1969), the interpretation of this question by the administering agency is "of controlling weight unless it is plainly erroneous or inconsistent with the regulation." Thus, a state regulation differing from the standard would impair the Federal superintendence of the field within the meaning of the doctrine set forth in Florida Lime & Avocado Growers v. Paul, 373 U.S. 132, 141-142 (1963) and be preempted under section 103(d) of the National Traffic and Motor Vehicle Safety Act of 1966, U.S.C. 1392(d). |
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ID: nht90-3.16OpenTYPE: Interpretation-NHTSA DATE: July 12, 1990 FROM: Michael L. Hayes TO: James Gilkey -- NHTSA TITLE: Re Non Compliance to Standard 213 in the Transport Incubator ATTACHMT: Attached to letter dated 1-15-91 from Paul J. Rice to Michael L. Hayes (A37; Std. 213; FMVSS 102(4)); Also attached to letter dated 7-12-90 from Michael L. Hayes to General Curry TEXT: In our resent phone conversation regarding transport safety for the new born infant which is transported in incubators, I brought to your attention that the child restraint equipment used in this area does not meet Standard 213. I have enclosed a sales brochure to illustrate my point. It is anticipated that the companies involved will claim that, due to the special circumstances involved in this type of transport, Standard 213 cannot be met and, thus, is not applicable to transport incubators. In view of this objection, I have included a copy of an engineering analysis of a restraint technique showing a design that can meet Standard 213 and meet the special needs of this type of transport as well. It is estimated that close to 100,000 infants are transported in this type of equipment each year. If only one half of one percent of these infants are injured due to the lack of proper protection, this represents hundreds of needless injuries and possi bly scores of deaths. The companies involved are aware of the moldable air-bag restraint technique and its ability to vastly improve the safety of the infant. However, the belief that it would not be profitable "enough" to up grade the transport incubator with proper occupant protection has lead to the continued sales of substandard equipment. This equipment is designed and sold specifically as a "transport" incubator in that its principal purpose is the transport of the infant. It is clear that if this equipment is capabl e of meeting child transport safety standards through specifically designed occupant protection systems the compliance should be halted. I would like to ask that you take up this project on behalf of the infant and enforce Standard 213 as it applies to "car bed" type restraints. Attachment Air-Shields Vickers sales brochure entitled TI-100 Infant Transport Incubator (Text omitted) Attachment An Engineering Analysis of a Developmental Transport Restraint System for the Neonate by Michael L. Hayes and Dr. Brent Coleman (Text and graphics omitted) |
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.