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: aiam5102OpenRobert R. McAusland, P.E. 1311 N. 35th St. Seattle, WA 98103; Robert R. McAusland P.E. 1311 N. 35th St. Seattle WA 98103; "Dear Mr. McAusland: This responds to your letter asking whether you design of an infant seat would comply with S5.2.4 of Federal Motor Vehicle Safety Standard No. 213, Child Restraint Systems. You state that your infant seat would have a frame made from 1/4 inch thick polyethylene sheet, and that all the edges of the frame are rounded to a radius of 1/8 inch. As discussed below, the design would not comply if the edges of the seat frame are contactable by the infant dummy's head or torso during the standard's dynamic test. Some background information on Federal motor vehicle safety laws and regulations may be helpful. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., Safety Act) authorizes this agency to issue safety standards applicable to new motor vehicles and items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. 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 following represents our opinion based on the facts set forth in your letter. Standard No. 213 specifies requirements for child restraint systems used in motor vehicles and aircraft, to reduce the number of children killed or injured in motor vehicle crashes and in aircraft. S5.2.4, 'Protrusion limitation,' of Standard No. 213 states: Any portion of a rigid structural component within or underlying a contactable surface, or any portion of a child restraint system surface that is subject to the requirements of S5.2.3 the head impact protection requirements for infant seats , shall, with any padding or other flexible overlay material removed, have a height above any immediately adjacent restraint system surface of not more than 3/8 inch and no exposed edge with a radius of less than 1/4 inch. (Emphasis added.) The term 'contactable surface' is defined in S4 of the standard as 'any child restraint system surface (other than that of a belt, belt buckle, or belt adjustment hardware) that may contact any part of the head or torso of the appropriate test dummy, specified in S7, when a child restraint system is tested in accordance with S6.1.' Under S5.2.4, any edges of a rigid structural component within or underlying a surface that can be contacted by the head or torso of the appropriate test dummy during Standard No. 213's dynamic test must have a radius of at least 1/4 inch. Since the frame edges of your infant seat have a radius of only 1/8 inch, the seat would not comply with S5.2.4 if the surfaces overlying those edges can be contacted by the infant dummy during the dynamic test. You ask whether, since side loading is not specified in Standard No. 213, can you conclude that there is no way that the child's head or torso could contact the sides of the frame, i.e., that the surfaces overlying those edges cannot be contacted by the infant dummy during the dynamic test. We assume that you believe the infant's head and torso are unlikely to contact the frame's edges in the 213 dynamic test since, due to the forward motion of the test, the dummy's components are likely to move forward and rearward, rather than laterally. I note that, for purposes of compliance testing, NHTSA would determine whether the surfaces are contactable surfaces for the purposes of S5.2.4 by observing a dynamic test, conducted according to the procedures in Standard No. 213. With respect to the issue of what information or analysis would be sufficient, for purposes of certification, for you to conclude that the surfaces overlying those edges cannot be contacted by the infant dummy during the dynamic test, manufacturers must have some basis for their certification that a product complies with all applicable safety standards. However, this does not necessarily mean that a manufacturer must conduct the specific tests set forth in an applicable standard. Certifications may be based on, among other things, engineering analyses, actual testing, and computer simulations. You should be aware, however, that the direction of dummy movement during the Standard No. 213 dynamic test depends on many variables other than the direction of the test, such as the performance of the restraint's belt system. For example, in the event a child seat's upper torso restraint slipped off the dummy's shoulder in the dynamic test, the dummy could move laterally and strike the sides of the restraint system. You should consider all of the variables that could affect the dummy's performance when determining whether frame contact can occur. I also note that manufacturers of motor vehicles and motor vehicle equipment are subject to the defect provisions of the National Traffic and Motor Vehicle Safety Act. Infant restraints are involved in real-world crashes other than the frontal impacts simulated in Standard No. 213. If data indicated that a child seat exposed occupants to an unreasonable risk of injury, such as sharp edges resulting in injuries in a side crash, the agency might conduct a defect investigation which could lead to a safety recall. Enclosed is an information sheet which provides additional information for new manufacturers of motor vehicles and motor vehicle equipment. If you have further questions, please call Ms. Deirdre Fujita of my staff at (202) 366- 2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam0300OpenMr. Y. Nakajima, Manager, Engineering Department, Koito Manufacturing Co., Ltd., 4-8-3 Takanawa, Minato-Ku, Tokyo, Japan; Mr. Y. Nakajima Manager Engineering Department Koito Manufacturing Co. Ltd. 4-8-3 Takanawa Minato-Ku Tokyo Japan; Dear Mr. Nakajima: This is in reply to your letter of February 25, 1971, concerning th photometric requirements for amber turn signal lamps.; You have correctly interpreted the photometric requirements for ambe turn signal lamps as specified in paragraph S4.1.1.7 of Federal Motor Vehicle Safety Standard No. 108, effective January 1, 1972.; Sincerely, Roger H. Compton, Director, Office of Operating Systems Motor Vehicle Programs; |
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ID: aiam5552OpenMr. Stuart Sacks Tradepro, Inc. 7350 N.W. 35th Street Miami, FL 33122; Mr. Stuart Sacks Tradepro Inc. 7350 N.W. 35th Street Miami FL 33122; "Dear Mr. Sacks: This responds to your letter to Mr. Philip Recht, ou former Chief Counsel, in which you stated that you are considering importing tires from the Hangzhou General Rubber Factory, which has been assigned NHTSA manufacturer identification number 7D. You stated that the tires do not display the 'molded D.O.T. code numbers,' and that Federal motor vehicle safety standard (FMVSS) No. 119, New pneumatic tires for motor vehicles other than passenger cars (49 CFR 571.119), 'clearly does not require DOT code numbers for non-passenger tires.' Your reading of FMVSS No. 119 is not correct. I assume from your letter that you are considering importing only non-passenger car tires. This letter, then, will address only the labeling requirements for non-passenger car tires under FMVSS No. 119 and 49 CFR 574. I further assume that by 'DOT code numbers' you mean the tire identification number (TIN) required by 49 CFR 574.5. 49 U.S. Code 30112 provides that no person may sell in or import into the United States any new motor vehicle or new item of motor vehicle equipment that does not comply with all applicable FMVSSs. With respect to non-passenger car tires, which are items of motor vehicle equipment, section S6.5 of FMVSS No. 119 requires specific items of information to be marked on the tire sidewalls. Those markings must be no less than 0.078 inch high and must be 'raised above or sunk below the tire surface' a specified distance. Among other things, the markings must include the TIN (S6.5(b)). Paragraph S6.5(b) of FMVSS No. 119 requires the TIN to comply with part 574. Part 574.5 requires that the TIN be permanently molded into or onto tire sidewalls as specified in Figure 1 of Part 574, and specifies what information the TIN must contain. The TIN can be branded into or onto the sidewalls of retreaded tires after the fact, but not new tires. On new tires, the TIN must be molded into or onto the tire sidewalls by the original manufacturer. I hope this information is helpful to you. Should you have any further questions or need additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam2297OpenMr. R. A. Plummer, Vice President & General Manager, Rome Engineering & Manufacturing Co., P.O. Box 707, Claxton, GA 30417; Mr. R. A. Plummer Vice President & General Manager Rome Engineering & Manufacturing Co. P.O. Box 707 Claxton GA 30417; Dear Mr. Plummer: This responds to Remco's April 26, 1976, question whether an exclusio from a safety standard based on the gross axle weight rating (GAWR) of an axle is met by using the rating of the axle beam by its manufacturer, or whether the truck or trailer manufacturer must also consider the load-bearing abilities of the wheels, rims, and hubs used with the axle beam.; Gross axle weight rating is defined in 49 CFR 571.3 to mean: >>>. . .the value specified by the vehicle manufacturer as th load-carrying capacity of a single axle system, as measured at the tire-ground interfaces.<<<; This definition means that the determination of GAWR is made by th vehicle manufacturer and that the axle beam rating of the component suppler cannot be the only basis for GAWR calculation. The GAWR is the value established at the tire-ground interfaces at each wheel position, and this means that the wheels, rims, hubs, and tires must be included in the determination. Thus, with regard to the exclusion from Standard No. 121, *Air Brake Systems*, until September 1, 1977, for any vehicle with an axle that has a GAWR of 24,000 pounds or more, the vehicle manufacturer must take into consideration each component on the axle as well as its attachment to the vehicle frame.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam1842OpenHonorable Les AuCoin, House of Representatives, Washington, DC 20515; Honorable Les AuCoin House of Representatives Washington DC 20515; Dear Mr. AuCoin: This is in response to your letter of March 11, 1975, forwarding comment from one of your constituents, Mr. Keith A. Burbidge, on the proposed weakening of the bumper standard.; On January 2, 1975, the National Highway Traffic Safety Administratio (NHTSA) issued a Federal Register notice (copy enclosed) proposing to reduce the current 5 mph bumper impact requirements to 2.5 mph until the 1979 model year. The impact requirements would then have been increased to 4 mph for 1979 and later model year cars.; The proposal was based primarily on the results of two agency-sponsore studies which indicated that the cost and weight of many current production bumpers, in light of inflation and fuel shortages, made the bumpers no longer cost beneficial. Information presented at public hearings on the bumper notice and comments submitted to the docket in response to the proposal have brought to light additional data. The NHTSA has carefully examined all of this evidence and reviewed its studies in light of the new information. As a result, the agency has concluded that the 5 mph protection level should not be reduced. This decision is contained in a Federal Register notice that was published March 12, 1975 which is enclosed (Docket No. 74-11, Notice 7, Docket No. 73-19, Notice 6).; Mr. Burbidge appears to be directing his comments to what he believe to be a proposed requirement that vehicles manufactured in the future be equipped with plastic bumper systems. Such an understanding of the proposal is incorrect. The January 2, 1975 proposal was aimed at enabling a reduction in vehicle weight. In the preamble to that notice, the NHTSA cited soft face bumpers as one type of system that could produce a significant weight reduction. However, no proposal was made to require the use of soft face systems. The March 12, 1975 notice reiterates the agency's position that bumpers which are lighter in weight than those currently in mass production could and probably would be developed. The requirements proposed in the March notice, however, ensure that a wide variety of materials could continue to be used in bumper systems.; We have placed Mr. Burbidge's letter in the appropriate docket. Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam0750OpenMr. Keitaro Nakajima, Director/General Manager, Factory Representative Office, Toyota Motor Sales, U.S.A., Inc., 1099 Wall Street West, Lyndhurst, NJ 07071; Mr. Keitaro Nakajima Director/General Manager Factory Representative Office Toyota Motor Sales U.S.A. Inc. 1099 Wall Street West Lyndhurst NJ 07071; Dear Mr. Nakajima:#In your letter of June 19 you ask whether a propose headlamp symbol would meet the requirements of Standard No. 101.#The NHTSA answered this question in a notice published in the *Federal Register* on May 4, 1971 (36 F.R. 8296). In responding to a question by General Motors whether the published headlamp identification symbol was only representative of the required symbol, or definitive in the sense that it must be copied exactly, the NHTSA stated that it intended the symbol to be representative only.#I enclose a copy of the notice for your information.#Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam1792OpenMr. Lamar Washington, Jr., General Manager, M.I.T. Innovation Co-op, Room 33-111 Innovation Center, Cambridge, MA 02139; Mr. Lamar Washington Jr. General Manager M.I.T. Innovation Co-op Room 33-111 Innovation Center Cambridge MA 02139; Dear Mr. Washington: This is in reply to your letter of January 24, 1975, to the Office o Chief Counsel asking whether your proposed 'Autocycle' is a 'motorcycle' for purposes of the Federal motor vehicle safety standards.; The Autocycle has a steerable front wheel and a rear traction whee arranged in tandem like a conventional two-wheeled motorcycle. However, it also has a pair of smaller side wheels that are lowered to the ground to assist in the stabilization of the vehicle at low speeds and while standing still. These auxiliary wheels, as we understand it, retract at moderate and high speeds.; A 'motorcycle' is a 'motor vehicle with motive power having a seat o saddle for the use of the rider and designed to travel on not more than three wheels in contact with the ground' (49 CFR 571.3(b)). Although you have not specified the low speeds at which the auxiliary wheels are deployed, we have concluded on the basis of the information you have provided that the Autocycle is essentially designed to travel on two wheels in contact with the ground, and that the auxiliary wheels serve only the limited function of providing stabilization at low speeds. Therefore, the Autocycle is a 'motorcycle' for purposes of compliance with the Federal standards.; The proposed redefinition of 'motorcycle (39 FR 15046, April 30, 1974 would exclude certain three-wheeled vehicles and thus does not affect the Autocycle.; Sincerely, James C. Schultz, Acting Chief Counsel |
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ID: aiam0880OpenMr. Ken J. Brown, Product Engineering Manager, Wayne Corporation, Post Office Box 908, Industries Road, Richmond, IN 47374; Mr. Ken J. Brown Product Engineering Manager Wayne Corporation Post Office Box 908 Industries Road Richmond IN 47374; Dear Mr. Brown: This is in response to your request of August 15, 1972, for a interpretation of Standard 217, Bus Window Retention and Release.; It is true that S5.3.2(a)(3) of the standard presently requires maximum torque of 20 inch-pounds. Your discussion of this requirement as it relates to the rotary mechanism you describe has, however, called our attention to a possible problem in the application of the standard. We are presently considering rulemaking to deal with the questions raised, and will notify you of our disposition of the matter. I regret any inconvenience the resultant delay in answering your question may cause you.; Sincerely, Richard B.Dyson, Assistant Chief Counsel |
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ID: aiam3255OpenMr. Adam Victor, Chairman and CEO, Gas Alternative Systems, 65 Rugby Road, Brooklyn, NY 11226; Mr. Adam Victor Chairman and CEO Gas Alternative Systems 65 Rugby Road Brooklyn NY 11226; Dear Mr. Victor: This responds to your March 1, 1980, letter asking what you must do t certify devices that you plan to import for sale in the United States. The devices to which you refer would convert an automobile's fuel system from gas to compressed natural gas or propane.; The National Highway Traffic Safety Administration issues safet standards and requires manufacturers of motor vehicles and equipment to certify that their vehicles or equipment comply with all applicable standards. To certify compliance to the standards, manufacturers must test or conduct some form of analysis of their vehicles or equipment. The Federal government does not get involved in the actual certification process. Once a manufacturer determines that its equipment or vehicles comply with the standards, it can then certify the vehicles or equipment without getting government approval.; With respect to the device that you propose to import, the agency ha no safety standards applicable to this type of a device. Accordingly, as an importer of this equipment, you would have no certification responsibilities. However, the agency has a vehicle safety standard regulating fuel systems. If your device were designed to be installed in new motor vehicles, the manufacturer of those vehicles would be required to insure that your device would comply with the standard applicable to fuel systems. If your device would be installed on used vehicles, no manufacturer, dealer or repair business would be permitted to install it if such installation would render inoperative the compliance of the vehicle with the safety standards.; To help clarify these general guidelines further, I am enclosing a cop of Part 567, *Certification*, which describes how to certify a vehicle in compliance with the safety standards. Further, I am enclosing a copy of our Safety Standard No. 301, *Fuel System Integrity*, which details the fuel system requirements for motor vehicles. Finally, we have prepared a short letter that gives information on the installation of alternate fuel systems in motor vehicles and that is enclosed for your information.; If we can be of further assistance, please contact us. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1268OpenMr. Gene J. Shapiro, The Temple Building, Suite 707, Seventy- seven West Washington Street, Chicago, IL 60602; Mr. Gene J. Shapiro The Temple Building Suite 707 Seventy- seven West Washington Street Chicago IL 60602; Dear Mr. Shapiro: This is in reply to your letter of August 28, 1973, concerning Federa Motor Vehicle Safety Standard No. 218, 'Motorcycle Helmets.' You request information regarding the American National Standards Institute (ANSI) Standard Z90.1, and all existing State standards or regulations requiring the use of headgear by motorcyclists.; First, it appears you may be under the impression the Z90.1 standar and its revisions were issued by the Federal Government. This is not the case. Although the requirements of Federal Motor Vehicle Safety Standard No. 218 are largely, though not entirely, based on the Z90.1-1971 Standard published by the American National Standards Institute, the Institute is a private organization neither sponsored nor supported by the Federal Government. You will have to write to the ANSI if you want any information concerning the Z90.1 standard and its revisions.; You may obtain the existing State standards or regulations requirin the use of headgear by motorcyclists from the Department of Motor Vehicles in each State, respectively. However, it may interest you to know that any State or local requirements for the design or performance of motorcycle helmets, that have a bearing on safety, will have to be identical to the requirements of the Federal standard when the Federal standard goes into effect.; A copy of Standard No. 218 and a copy of the National Traffic and Moto Vehicle Safety Act of 1966, are enclosed for your information.; 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.