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: aiam3699OpenMr. Stephen E. Parmeter, Route 4, Potsdam, NY 13676; Mr. Stephen E. Parmeter Route 4 Potsdam NY 13676; Dear Mr. Parmeter: This responds to your recent letter concerning the process of repairin breaks in automobile windshields. You ask whether such repairs would conflict with any present Federal motor vehicle safety standards.; The National Highway Traffic Safety Administration has issued Federa Motor Vehicle Safety Standard No. 205 which specifies performance and location requirements for glazing materials used on motor vehicles (copy enclosed). This standard would not apply to a repair process such as you describe, however. There is no Federal regulation which would prohibit the use of a product or process in the repair of windshields which have previously been installed in vehicles and damaged in use.; Please note, however, that using such a material or process in a ne windshield which may require repair (as a result of damage sustained, for example, in shipment) could cause the windshield to fail to meet the performance requirements of Safety Standard No. 205, or could fail to bring a noncomplying windshield back into compliance. Either case of noncompliance would be the responsibility of the person selling the windshield (49 CFR 567.7, copy enclosed). Therefore, we do not recommend use of windshield repair processes prior to the first purchase of a new windshield by a consumer.; You will have to contact a private attorney to determine your liabilit under civil law with regards to such a business.; Please contact Hugh Oates of my staff if you have any furthe questions.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2122OpenHonorable John P. Murtha, House of Representatives, Washington, DC 20515; Honorable John P. Murtha House of Representatives Washington DC 20515; Dear Mr. Murtha: This responds to your November 5, 1975, request for the criteri necessary for construction of testing equipment used to demonstrate compliance with Standard No. 121, *Air Brake Systems*.; The motor vehicle safety standards, including Standard No. 121, ar established as requirements that vehicles must be capable of meeting if tested by the National Highway Traffic Safety Administration (NHTSA). However, the standards are not developed as demonstration procedures that detail methods a manufacturer would use to establish that its products comply. The development of actual test protocols to determine that products conform to the requirements is the responsibility of the regulated industry and the associated industries that service them.; Thus the Thiele Corporation, as a manufacturer of air-braked vehicles may choose whatever test method gives it an adequate basis for certification that its products comply (15 U.S.C. S 1397(a)). Test equipment has been developed by several commercial sources, and Thiele can choose proper systems by consulting with the manufacturers of the brake components it uses. As for specifications for a test track, actual road tests are not necessary to establish compliance with Standard No. 121 where other reasonable means, such as engineering calculations coupled with laboratory tests, can be used to the same effect. Supplier warranties and instructions are one of the primary means by which small assemblers ascertain that their products conform.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2572OpenMr. Robert B. Kurre, Director of Engineering, Wayne Corporation, Post Office Box 1447, Industries Road, Richmond, IN 47374; Mr. Robert B. Kurre Director of Engineering Wayne Corporation Post Office Box 1447 Industries Road Richmond IN 47374; Dear Mr. Kurre: This responds to your April 1, 1977, letter asking whether the hea protection zone requirements of Standard No. 222, *School Bus Passenger Seating and Crash Protection*, extend to contactable surfaces 30 inches forward of the seating reference point of the front passenger seat behind the driver.; The head protection zone requirements are outlined in S5.3.1.1 of th standard. This section requires that the zone extend 30 inches forward of the seating reference point. The fact that the requirement may extend the head protection zone into the driver occupant space and thus involve contactable surfaces does not diminish the applicability of the requirements to contactable surfaces within that space. Contactable surfaces within that 30-inch zone, as shown on your sketch, must meet the requirements of the standard.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2088OpenMr. Heinz W. Gerth, Assistant Vice President, Mercedes-Benz of North America, Inc., P.O. Box 350, Montvale, NJ 07645; Mr. Heinz W. Gerth Assistant Vice President Mercedes-Benz of North America Inc. P.O. Box 350 Montvale NJ 07645; Dear Mr. Gerth: This is in response to your letter dated May 7, 1975, regarding a apparent conflict between the inertia load requirement of Standard 206, *Door Locks and Door Retention Components*, (49 CFR 571.206, S4.1.1.3) and the test procedure incorporated by S5.1.1.2, Paragraph 5 of SAE Recommended Practice J839b. I regret the delay in responding, your letter was mistakenly routed to our Docket Section and only recently came to our attention.; The answer to your question is that the requirement of S4.1.1. controls. It is sufficient that the door latch system withstand a 30g load only in the transverse and longitudinal directions. The system is not required to withstand this load in 'any direction.'; You asked further about the acceptability of centrifuge testing t demonstrate compliance with the inertia load requirement of Standard 206. Although S5.1.1.2 mentions 'approved tests,' NHTSA has consistently refused to approve or supervise the methods manufacturers use to test to the standard. Any government inertia load compliance testing will be done in accordance with paragraph 5 of SAE Recommended Practice J839b. Mercedes-Benz, of course, may employ any method it chooses to ensure compliance with this and other safety standards, as long as the product complies. We recognize that centrifuge testing may be highly useful in a variety of applications, and I do not by any means want to discourage innovations in developmental or compliance testing.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5063OpenMr. Paul D. Barron Professional Technologies International Inc. 400 South Vermont #116 Oklahoma City, OK 73108; Mr. Paul D. Barron Professional Technologies International Inc. 400 South Vermont #116 Oklahoma City OK 73108; "Dear Mr. Barron: This responds to your inquiry about this agency' requirements that are applicable to your product, a 'UV Heat Shield.' Your sales literature explains that this product is a UV protective window film that permits between 88 to 92 percent light transmission through the front windshield. You state that the UV Heat Shield blocks ultra-violet radiation from entering the vehicle's occupant compartment. I am pleased to have this opportunity to explain our regulations to you. By way of background information, section 103 of 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. In addition, the Safety Act requires manufacturers to recall and remedy any motor vehicle or item of motor vehicle equipment that contains a safety-related defect. Under the authority of the Safety Act, NHTSA has issued Standard No. 205, Glazing Materials, which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (e.g., 70 percent in areas requisite for driving visibility, which includes all windows in passenger cars). The purpose of this requirement is to ensure driver visibility through the windows, thereby reducing the risk of a motor vehicle crash. Manufacturers must certify that their new vehicles comply with the requirements of all applicable safety standards. If, before the vehicle were first purchased by a consumer, a subsequent manufacturer or dealer were to install your window film over the glazing, that subsequent manufacturer would be required to certify that the vehicle continues to comply with the requirements of Standard No. 205 with the window film installed. I note that while you state that your window film permits between 88 to 92 percent light transmission through the front windshield, it is the windshield with your product installed that would be required to meet the 70 percent light transmittance requirement. After a vehicle is first sold to a consumer, modifications to the vehicle are affected by 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits any manufacturer, distributor, dealer, or motor vehicle repair from knowingly 'rendering inoperative' any device or element of design installed in a vehicle in compliance with any applicable safety standard. This provision means that no manufacturer, dealer, distributor, or repair business could install window tinting film if the addition of the tinting film to the glazing would result in a light transmittance of less than 70 percent, or otherwise cause the vehicle to no longer comply with the applicable requirements of Standard No. 205. Violations of this 'render inoperative' prohibition can result in Federal civil penalties to the manufacturer, dealer, distributor, or repair business of up to $1,000 for each noncomplying installation. Section 108(a)(2)(A) of the Safety Act does not affect vehicle owners. Hence, vehicle owners themselves may install tinting film or any other product on the glazing of their vehicle, regardless of whether the installation causes the vehicle to no longer comply with Standard No. 205. Individual States have the authority to regulate the operational use of vehicles by their owners, and, therefore, have the authority to regulate or preclude individual owner modifications to the glazing of their vehicles. If you are interested in further information on the provisions on the provisions of State laws, you may wish to contact the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, VA 22203. In addition, under the Safety Act, the UV Heat Shield would be considered an item of motor vehicle equipment. Your company, as a manufacturer of motor vehicle equipment, would be subject to the requirements in 151-159 of the Safety Act concerning the recall and remedy of products with safety related defects. In the event that NHTSA or the product's manufacturer determines that a product that is an item of motor vehicle equipment contains a safety- related defect, the manufacturer is responsible for notifying purchasers of the defective equipment and remedying the problem free of charge. I have also enclosed a general information sheet for new manufacturers which summarizes NHTSA's regulations and explains where to obtain copies of Federal motor vehicle safety standards and other regulations. I hope that 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, Paul Jackson Rice Chief Counsel Enclosures"; |
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ID: aiam1889OpenMr. David M. Holden, Frigiking, Inc., 10858 Harry Hines Boulevard, Dallas, TX 75220; Mr. David M. Holden Frigiking Inc. 10858 Harry Hines Boulevard Dallas TX 75220; Dear Mr. Holden: Your letter of March 7, 1975 to Mr. Alex Calaluca, Motor Vehicl Programs Director of the National Highway Traffic Safety Administration's Region 6, has been referred to this office. You wish to be informed of Frigiking's responsibilities under the NHTSA's rules and regulations as a manufacturer of automotive air conditioners for sale to domestic and foreign auto manufacturers, automobile dealers and automobile supply retail outlets.; Mr. Calaluca correctly indicated that there is currently no Federa Motor Vehicle Safety Standard which regulates automobile air conditioners. He also correctly informed you that your firm is not deemed a manufacturer by the NHTSA when your product is installed as original equipment. Where the Frigiking air conditioner is installed in a vehicle prior the first sale of the vehicle the manufacturer of the vehicle is also deemed to be manufacturer of your product. However, you should understand that in all other cases your company is considered a manufacturer under the NHTSA's rules and regulations. For example, where units are sold under private label to mass merchandising firms for sale and installation to individual automobile owners, or where units are sold through Frigiking's distributor/dealer organization for individual unit retail sales where the sale is other than to a franchised auto dealer for installation prior to the sale of the new car, Frigiking has certain responsibilities under the National Traffic and Motor Vehicle Safety Act of 1966, as amended, notwithstanding the absence of any Safety Standard regulating air conditioners.; In the event that the NHTSA determined through its own investigatio that an air conditioner produced by your firm contained a defect related to motor vehicle safety, you would be required to give notice of the defect to every person who had purchased the produce manufactured during the period when a defect was known to exist. This manufacturing period could extend up to 8 years preceding the notification. In addition you would be required to repair or replace without charge every such defective air conditioner presented to you, and repurchase defective air conditioners from distributors and dealers.; Finally, it would be wise for Frigiking to remind manufacturers an dealers who install its air conditioners in motor vehicles prior to first sale that they must account for the addition of an air conditioning unit in certifying that the vehicle conforms to Federal standards and in certifying the Gross Vehicle Weight Rating and Gross Axle Weight Rating as required by the NHTSA regulations contained in 49 CFR Part 567.; Please do not hesitate to contact us if we can be of furthe assistance.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5599OpenSteven B. Fisher, Esq. Kostow & Daar, P.C. 200 South Wacker Drive Chicago, Illinois 60606; Steven B. Fisher Esq. Kostow & Daar P.C. 200 South Wacker Drive Chicago Illinois 60606; Re: Motor Vehicle Safety Standard No. 108 Dear Mr. Fisher: Thi responds to your letter of July 31, 1995, to Philip R. Recht, formerly Chief Counsel of this agency. You have asked several questions relating to use of the word 'practicable' in the lamp location requirements of Federal Motor Vehicle Safety Standard No. 108. Your first question is 'with respect to truck, trailer identification lights (red), what is meant exactly by `practicable' as used in SS5.3.1.1 and 5.3.1.4.' Your second question is whose responsibility it is to make the determination of practicability. Your final question is whether there is any way for a manufacturer of 'a single rear identification light' to know where a trailer manufacturer will install the product on any given trailer. We don't see the word 'practicable' in S5.3.1.1. However, S5.3.1.4 does provide that rear clearance lamps need not meet the requirement of Table II that they 'be located as close as practicable to the top of the vehicle' when the rear identification lamps are located at the extreme height of the vehicle. Table II specifies location of lighting equipment on the vehicle, and it is therefore the responsibility of the vehicle manufacturer, in certifying that its vehicle complies with all applicable Federal motor vehicle safety standards, to determine what is practicable. As you indicate, a trailer manufacturer may make such a determination 'in light of the particular design/configuration of the trailer involved.' NHTSA will not contest this determination unless it is clearly erroneous. In short, 'practicable' as meant by S5.3.1.4 or any other place where the word occurs, is not a term defined by Standard No. 108, and derives its meaning from specific factual contexts. We note that the Random House Dictionary of the English Language (1967) defines 'practicable' as 'capable of being done, effected, or put into practice with the available means' (p. 1127). There is no responsibility under Standard No. 108 for the manufacturer of identification lamps to know where its products will be installed on the motor vehicle. Its responsibility under Standard No. 108 is to ensure that any identification lamp that it manufactures for replacement purposes is designed to conform to Standard No. 108's performance specifications and so certified at the time the lamp is shipped from the factory. If you have any further questions you may phone Taylor Vinson of this office (202-366-5263). Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam0261OpenMr. Gerald Sagerman, U.S. Agent, TVR Engineering, Ltd., 572 Merrick Road, Lynbrook, NY 11563; Mr. Gerald Sagerman U.S. Agent TVR Engineering Ltd. 572 Merrick Road Lynbrook NY 11563; Dear Mr. Sagerman: This is in response to your letter of October 14, 1970, to the Directo of the National Highway Safety Bureau forwarding information sheets on the TVR Vixen. I am enclosing copies of the Bureau's Consumer Information Regulations (49 CFR Part 575). The substantive provisions, S 575.101 on vehicle stopping distance, S 575.102 on tire reserve load, and S 575.106 on acceleration and passing ability, require the furnishing of specific information in a format which is in the form set out in the regulations. The information sheets which you have provided fall short of these requirements in both form and substance. For example, S 575.101 requires furnishing information on the minimum stopping distance, expressed in feet, for the particular vehicle, from a particular speed, at specified loads, with the braking system in a specified condition. The information provided by you in this regard is incomplete, and is not in the form specified. In addition, the regulations require the information to describe and be valid for each of the vehicles with which it is provided.; Please study the enclosed regulations carefully and forward to u complying consumer information within the near future. Let us know if you need further assistance.; Sincerely, Rodolfo A. Diaz, Acting Associate Director, Motor Vehicl Programs; |
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ID: aiam5433OpenMs. Irene M. Thomas 1627 S. Ironton St. Aurora, CO 80012; Ms. Irene M. Thomas 1627 S. Ironton St. Aurora CO 80012; "Dear Ms. Thomas: This responds to your letter asking about safet regulations for a device you call a 'CarMobile.' The CarMobile is a type of strap to which three rings are sewn. The CarMobile attaches by 'velcro' straps to the handrails located at the top of the interior rear car doors. You state that 'Toys would be hung from the rings, so that babies and toddlers can play with them as they dangle in front of their carseats.' By way of background information, the National Highway Traffic Safety Administration (NHTSA) has the authority 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, each manufacturer is responsible for 'self-certifying' that its products meet all applicable safety standards. The agency periodically tests vehicles and items of equipment for compliance with the standards. In response to your question, there is currently no Federal motor vehicle safety standard (FMVSS) that directly applies to the product you wish to manufacture. However, 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 of 49 U.S.C. 30118-30121 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 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. In addition, while it is unlikely that the CarMobile would be installed by a motor vehicle manufacturer, distributor, dealer or repair business, 49 U.S.C. 30122 prohibits those businesses from installing the device if the installation 'makes inoperative' compliance with any safety standard. NHTSA's safety standard for built-in child restraint systems (Standard 213) specifies requirements that ensure that the area surrounding a child in a built-in restraint is free from objects that could injure a child's head in a crash. If the CarMobile's cord and rings cause the vehicle with the built-in restraint to no longer comply with Standard 213, any of the aforementioned parties installing the CarMobile may have violated 30122. The prohibition of 30122 does not apply to individual owners who install equipment in their own vehicles. Thus, individual owners may install any item of motor vehicle equipment regardless of its effect on compliance with Federal motor vehicle safety standards. However, NHTSA encourages vehicle owners not to degrade the safety of their vehicles, and would discourage them from hanging toys or other objects in front of a seated child that could injure the child in a crash. We also wish to point out that any kind of ribbon or line that can wrap around the neck of a child in a crash poses a potential risk of strangulation in a crash. You should consider these and any other relevant safety concerns when designing the CarMobile and when instructing consumers how to use the device. I hope this is helpful. If you have any other questions, please contact Deirdre Fujita 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: aiam0631OpenMr. Thomas S. Pieratt, Jr., Executive Secretary, Truck Equipment & Body Distributors Association, 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Jr. Executive Secretary Truck Equipment & Body Distributors Association 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in reply to your letter of February 23, 1972, concerning th application of the Certification regulations (49 CFR Part 567) to certain vehicles and components.; You describe a device, called a 'converter gear', which is used t convert a semi-trailer into a trailer, and ask whether this unit is considered to be a trailer which must be certified. You also ask whether all lamps and reflectors specified for trailers are required. We believe this device to be a trailer, and it appears from your description that it is a 'trailer converter dolly' under the Motor Vehicle Safety Standards (49 CFR S571.3). Trailer converter dollies are specifically exempt from the requirements of Motor Vehicle Safety Standard No. 108, 'Lamps, Reflective Devices, and Associated Equipment,' and are consequently not required to meet the lighting requirements applicable to other trailers. In addition, there are presently no other motor vehicle safety standards applicable to trailers and consequently, trailer converter dollies need not be certified. This will no longer be the case, however, after the effective date of Standard No. 121, 'Air Brake Systems.' Trailer converter dollies manufactured on or after that standard's effective date will be required to comply with its requirements, and to be certified in accordance with Part 567.; You also ask how manufacturers are to determine the GVWR fo semi-trailers, and whether such a figure can be based solely on the semi-trailer's axle or axles. The GVWR of a semi-trailer should not be based on the vehicle's axles. The definition of GVWR calls for the weight *of a fully loaded vehicle*, and normally the capacity of a semi-trailer is greater than that of its rear axles.; You describe another device, a 'Jo-Dog' or detachable tab axle to b attached to a truck tractor, asking whether this unit is a 'trailer' which must be certified and whether the use of such a device would alter the truck tractor to the extent that an altered certification label is required. It appears from your description of this device that it is also a 'trailer converter dolly.' As in the case of the 'converter gear' described above, certification by the manufacturer (at the present time) is not required. Moreover, we would not consider the use of such a device to be 'manufacturing' within the National Traffic and Motor Vehicle Safety Act, and no certification of any kind by a user (as distinguished from a manufacturer) would be required.; Finally you describe additional devices, a 'drom,' and an auxiliar cargo-carrying platform, both of which can be added to truck tractors between the cab and the fifth wheel. You ask whether the installation of such devices would constitute re-manufacturing of the vehicle and if additional certification is required when compliance to a standard is not altered.; We would consider the addition of such components to a new vehicle t be manufacturing under the National Traffic and Motor Vehicle Safety Act, and certification by the vehicle manufacturer would be required regardless of whether compliance of the vehicle to any standard is affected.; We are pleased to be of assistance. Yours truly, Richard B. Dyson, Assistant 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.