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: aiam1956OpenMr. Samuel W. Alderson, President, Humanoid Systems, Division of Alderson Biotechnology Corporation, 5250 El Segundo Boulevard, Hawthorne, CA 90250; Mr. Samuel W. Alderson President Humanoid Systems Division of Alderson Biotechnology Corporation 5250 El Segundo Boulevard Hawthorne CA 90250; Dear Mr. Alderson: This is in response to your letter of May 30, 1975, to th Administrator.; Thank you for the offer to assist in the establishment of ne specifications for dummy skin and flesh components. Any procurement of such services would be awarded by competitive procurement, and I hope your company will participate in any such competition when solicited.; The NHTSA issued Part 572, in the form of a large number of dumm design and material specifications supplemented by some calibrating component tests, in order to specify the vehicle performance requirements of certain crash-test standards, such as Standard No. 203, as precisely and objectively as possible. Dummies are not regulated items and not ends in themselves, as S 572.3 states, the dummy specification 'does not in itself impose duties or liabilities on any person.' Thus, the dummy specification serves only as a means of informing the vehicle manufacturers how their vehicles must perform if and when tested by the government. There is no regulatory requirement either for 'certification' of dummies or their 'verification by an independent agency' or anyone else. It may be assumed that government testing will be carried out with dummies that conform to Part 572 as closely as possible. Vehicle manufacturers can ascertain that their vehicles will pass government tests by any means they choose. With this in view, it should be clear that any deviations from the Part 572 specifications are purely a matter of private negotiation and decisionmaking between the dummy manufacturers and their customers, and no governmental 'approvals' are possible or appropriate.; Any changes in Part 572 will of course be done through notice an opportunity for comment, and we expect and hope for your full participation in an administrative proceeding when it takes place.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam0644OpenMr. Gorou Utsunomiya, Chief, Liaison Engineer, Toyo Kogyo Detroit Office, 3841 Mystic Valley Dr., Bloomfield Hills, Michigan 48013; Mr. Gorou Utsunomiya Chief Liaison Engineer Toyo Kogyo Detroit Office 3841 Mystic Valley Dr. Bloomfield Hills Michigan 48013; Dear Mr. Utsunomiya: This is in response to your letter of March 16, 1972, in which you as whether the definition of 'unloaded vehicle weight' is the same as or 'curb weight' plus optional parts, and whether the definition of 'gross vehicle weight' is the same as that for 'maximum loaded vehicle weight.'; The two sets of definitions are expressed in substantially differen terms. The new terms, 'unloaded vehicle weight' and 'gross vehicle weight rating' are more general than the older ones. The newer terms also eliminate some ambiguities in the definitions based on 'curb weight,' such as just what is meant by 'standard equipment,' and whether other vehicle fluids besides fuel, oil, and coolant should be included. Further, GVWR is a rating, not necessarily identical to any scale weight although some constraints have been placed on it in our Certification regulations (S567.4(g)(3)).; Thus although the two sets of definitions are somewhat similar in thei application, they are different enough that each must be interpreted and used in its own terms.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2679OpenMr. Stephen C. Nimmer, Senior Supervising Engineer, Oshkosh Truck Corporation, Box 2566, Oshkosh, WI 54901; Mr. Stephen C. Nimmer Senior Supervising Engineer Oshkosh Truck Corporation Box 2566 Oshkosh WI 54901; Dear Mr. Nimmer: This is in reply to your letter of August 29, 1977, asking fo confirmation of your interpretation of S4.5.4 of Motor Vehicle Safety Standard No. 108.; Paragraph S4.5.4 requires that 'The stop lamps on each vehicle shall b activated upon application of the service brakes.' Oshkosh trucks are equipped with split air brake systems. This system incorporates a parking brake system on the rear axles. You indicated that there are three conditions under which the parking brakes will apply:>>>; Condition 1. - Parking Application. The spring brakes are driver applied through a hand operated parkin control.; Condition 2. - Rear Service Brake System Failure. The spring brakes can be driver applied through the service brake foo operated treadle valve control in the event of a failure in the rear service brake system.; Condition 3. - Spring Brake Cavity Pressure Loss. A component failure which allows air pressure to exhaust from th spring cavity of the rear brake chambers will cause the spring brakes (parking brakes) to apply. This condition is not driver initiated.'<<<; You have interpreted Condition 2 as the only 'services brake application since it is the only one of the three that is driver-initiated through the service brake control, and that stop lamp activation under the other two Conditions is not required by Standard No. 108.; This will confirm your interpretation. With respect to Condition 1, w do not consider that driver application of the parking brake portion of the service brake system is 'application of the service brakes' within the meaning of S4.5.4. Nor do we consider that activation of the parking brakes through component failure is 'application of the service brakes', your Condition 3.; Sincerely, Frank Berndt, Deputy Chief Counsel |
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ID: aiam5446OpenMr. Michael Winzkowski FABA Autoglas Produktion c/o Farmont Sunroofs, Ltd. 2346 Success Drive P.O. Box 981 Odessa, FL 33556-0981; Mr. Michael Winzkowski FABA Autoglas Produktion c/o Farmont Sunroofs Ltd. 2346 Success Drive P.O. Box 981 Odessa FL 33556-0981; "Dear Mr. Winzkowski: This responds to your letter about manufacturer's certification responsibilities under Federal Motor Vehicle Safety Standard No. 205, Glazing materials (49 CFR 571.205, copy enclosed). You state that you are a United States-based subsidiary of a German automotive sunroof manufacturer. You are having problems explaining to the German authorities the differences between the certification requirements of the two countries and request a letter explaining that the U.S. uses a self-certification procedure. I am pleased to provide this information. As you know, every item of glazing for use in motor vehicles that is sold in or imported into this country must be certified as complying with FMVSS No. 205. This standard sets forth both performance and labeling requirements that must be satisfied by the automotive glazing. In enforcing its safety standards, the National Highway Traffic Safety Administration (NHTSA), which is part of the U.S. Department of Transportation, does not follow the European practice of requiring the manufacturer of motor vehicle equipment to deliver an item of the equipment to specified institutes for testing before the product can be sold. Instead, as required by the U.S. Congress, the manufacturer 'self-certifies' that each of its items of motor vehicle equipment fully satisfies all requirements of the applicable Federal motor vehicle safety standards. Thus, each item of automotive glazing is self-certified by its manufacturer as complying with FMVSS No. 205. NHTSA does not require that the manufacturer's certification be based on a specified number of tests of the glazing or on any tests at all. Under the statute, the agency only requires that the certification be made with the exercise of 'due care' on the part of the manufacturer. It is up to the manufacturer to determine what data, test results, or other information is needed to enable it to certify that the glazing complies with Standard No. 205. We do recommend, however, that a manufacturer selling its glazing in the United States for the first time test those products, according to the test procedures specified in Standard No. 205. Once the manufacturer has determined that its glazing complies with the requirements of Standard No. 205, it certifies that compliance by marking the glazing with the symbol DOT, as specified in section S6 of Standard No. 205. You specifically asked for verification that 'no US DOT testing or certification is conducted when DOT numbers are assigned to manufacturers.' The 'DOT number' to which you refer is the manufacturer's code mark that is assigned by NHTSA on request of the glazing manufacturer (S6.2 of FMVSS No. 205). Your understanding is correct. NHTSA does not test glazing products or review manufacturers' compliance data prior to or as a condition for assigning a manufacturer's code mark pursuant to S6.2 of Standard No. 205. I hope you find this information helpful. If you have any other questions, please contact Mr. Marvin Shaw of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam2383OpenMr. Richard J. Brandewie, Program Manager, B.F. Goodrich Engineered Systems Company, P.O. Box 340, Troy, OH 45373; Mr. Richard J. Brandewie Program Manager B.F. Goodrich Engineered Systems Company P.O. Box 340 Troy OH 45373; Dear Mr. Brandewie: This responds to your July 26, 1976, question whether the 'no lockup requirement of S5.3.1 and S5.3.2 of Standard No. 121, *Air Brake Systems*, requires wheel sensors on both axles of a tandem axle system in those cases where the 'no lockup' performance is provided by means of an antilock system. I have enclosed a detailed discussion of this issue that responded to a similar question from another manufacturer. The response should answer your question.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam0214OpenMr. C. J. Newman, Director of Engineering, The Grote Manufacturing Company, State Route 7, P. O. Box 766 N. M. S., Madison, IN 47250; Mr. C. J. Newman Director of Engineering The Grote Manufacturing Company State Route 7 P. O. Box 766 N. M. S. Madison IN 47250; Dear Mr. Newman: Thank you for your letter of February 19, 1970, to Mr. Julian E Leysath of this Office asking for suggestions on lighting equipment for a trailer manufactured by Toter, Inc.; This will confirm your understanding that the Toter is considered trailer under the Federal Motor Vehicle Safety Standards, and not a dolly. Since the manufacturer is responsible for compliance with Federal Standard No. 108 (Lamps, Reflective Devices, and Associated Equipment) I am unable to provide specific suggestions or recommendations for lighting the vehicle in question.; Sincerely, Rodolfo A. Diaz, Acting Director, Motor Vehicle Safet Performance Service; |
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ID: aiam2229OpenMrs. Anderson, Inertia Switch, Ltd., Hardings Lane, Hartley Wintney, Hampshire, England RG278QA; Mrs. Anderson Inertia Switch Ltd. Hardings Lane Hartley Wintney Hampshire England RG278QA; Dear Mrs. Anderson: I am writing in response to your March 9, 1976, telephone conversatio with Mark Schwimmer of this office concerning the meaning of 'GVWR' as it appears in Federal Motor Vehicle Safety Standard No. 301-75, *Fuel System Integrity*.; 'GVWR' or 'Gross vehicle weight rating' is defined in 49 CFR 571.3 as: >>>the value specified by the manufacturer as the loaded weight of single vehicle.<<<; One constraint on this specification is found in S567.4(g)(3) of 49 CF Part 567, *Certification*, which requires that the GVWR shall not; >>>be less than the sum of the unloaded vehicle weight, rated carg load, and 150 pounds times the vehicle's designated seating capacity... .<<<; An information sheet entitled 'Where to Obtain Federal Motor Vehicl Safety Standards and Regulations' is enclosed for your convenience. If you have any further questions, please do not hesitate to write.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5016OpenThe Honorable John J. Duncan, Jr. House of Representatives Washington, DC 20515-4202; The Honorable John J. Duncan Jr. House of Representatives Washington DC 20515-4202; Dear Mr. Duncan: Thank you for your letter enclosing correspondenc from your constituent, Mr. Clarence Lowe, an instructor for Campbell County Comprehensive High School, concerning the use of 15-passenger vans to transport school children. Campbell County has been informed by the Tennessee State Department of Education that vans cannot be used to transport children to school or school-related events. In light of school budget constraints, Mr. Lowe would like to use these vehicles for transporting students to off-campus vocational programs. Your letter also enclosed a letter from Ernest Farmer, Tennessee Director of Pupil Transportation, explaining why the State of Tennessee has instructed schools not to use vans to transport school children. I am pleased to have this opportunity to clarify Federal law as it relates to school buses. The National Highway Traffic Safety Administration (NHTSA) has the authority under the National Traffic and Motor Vehicle Safety Act to issue motor vehicle safety standards that apply to the manufacture and sale of new motor vehicles, in order to reduce the number of fatalities and injuries that result from motor vehicle crashes. Under NHTSA's regulations, vans are generally classified as either multipurpose passenger vehicles (MPV's) or buses. The MPV category includes vans which carry 10 persons or less, vans which carry more than 10 persons are buses. Thus, the 15-passenger vans referred to by Mr. Lowe are classified as buses. Under the agency's definitions, a 'school bus' is a type of bus sold for transporting students to and from school or school-related events. All MPV's and buses are required to meet Federal motor vehicle safety standards. However, in the legislative history of the School Bus Safety Amendments of 1974, Congress stated that school transportation should be held to the highest level of safety. Accordingly, NHTSA has issued special Federal motor vehicle safety standards applicable to all new school buses. Like all safety standards, NHTSA's school bus standards impose obligations on the manufacturers and sellers of new motor vehicles, not upon the subsequent users of these vehicles. It is a violation of Federal law for any person to sell any new vehicle that does not comply with all school bus safety standards if the vehicle capacity is more than 10 persons, and if the seller is aware that the purchaser intends to use the vehicle as a school bus. On the other hand, without violating any provision of Federal law, a school may use a vehicle which does not comply with Federal school bus regulations to transport school children. This is so because the individual States, not the Federal government, have authority over the use of vehicles. However, I would like to call your attention to a guideline that NHTSA has issued under the authority of the Highway Safety Act of 1966. That Act authorizes the agency to issue guidelines for states to use in developing their highway safety programs. NHTSA issued Highway Safety Program Guideline 17, Pupil Transportation Safety, to provide recommendations to the states on various operational aspects of their school bus and pupil transportation safety programs. Guideline 17 recommends that any vehicle designed for carrying more than 10 persons which is used as a school bus comply with all safety standards applicable to school buses at the time the vehicle was manufactured. In conclusion, it is not a violation of Federal law for Campbell County to use its 15-passenger vans for transportation of school children, however, use of these vehicles may be restricted by Tennessee law. I must emphasize NHTSA's position that a vehicle meeting Federal school bus regulations is the safest way to transport students. Despite the additional cost of these vehicles, I encourage Campbell County to give its most careful consideration to the possible consequences of transporting students in vehicles that do not comply with these regulations. I hope this information is helpful. Sincerely, Jerry Ralph Curry; |
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ID: aiam3068OpenMr. G. Frinken, Manager, Automotive Engineering Europe, Uniroyal European Tire Development Center, Uniroyal GMBH, Postfach 410, 5100 Aachen 1, West Germany; Mr. G. Frinken Manager Automotive Engineering Europe Uniroyal European Tire Development Center Uniroyal GMBH Postfach 410 5100 Aachen 1 West Germany; Dear Mr. Frinken: This is in response to your letter of July 20, 1979, concerning th Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104). You ask whether it is permissible under the regulation to mold UTQG grades on only one sidewall of a tire and, in the case of a symmetrical black sidewall tire, whether the grades may be molded on the same sidewall as the tire identification number required by 49 CFR 574.5.; The UTQG Standards require that tire grades need be molded on only on sidewall of a tire. Since the regulation presently does not specify the sidewall on which tire grades must be molded, Uniroyal is legally permitted to mold UTQG grades on either sidewall of its tires. However, in order to facilitate consumer access to the grading information, the National Highway Traffic Safety Administration (NHTSA) encourages manufacturers to mold tire grades on the sidewall intended to be visible when the tire is mounted on a vehicle. NHTSA will monitor the placement of tire grades to determine whether further action is necessary to assure the accessibility of the grading information.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1055OpenMr. Elmer A. Brown, Registrar, Department of Motor Vehicles, P.O. Box 1319, Sacramento, CA 95806; Mr. Elmer A. Brown Registrar Department of Motor Vehicles P.O. Box 1319 Sacramento CA 95806; Dear Mr. Brown: This is in response to your letter of March 12, 1973, concerning th compliance of a proposed California form with the Federal Odometer Disclosure Requirements, 49 CFR Part 580.; The use of a combination form such as that proposed is acceptable s long as it contains the information required in Part 580. We have reviewed the proposed form and find that it complies with Part 580.; 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.