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: aiam1930OpenMr. Richard Schlichting, President, Toledo Clutch & Brake Service, Inc., 2112-24 Monroe Street, Toledo, OH 43624; Mr. Richard Schlichting President Toledo Clutch & Brake Service Inc. 2112-24 Monroe Street Toledo OH 43624; Dear Mr. Schlichting: This responds to your April 21, 1975, questions whether a 121-equippe chassis must be certified to Standard No. 121, *Air brake systems*, after installation of a tractor conversion kit, whether an antilock wiring harness may be spliced for purposes of frame extension, whether additional weight (such as a body) or an axle may be added to a vehicle after it is sold and put into use, and whether the standard regulates the replacement of worn brake components. You state that it should be assumed that the vehicle has been delivered to the first user.; The National Traffic and Motor Vehicle Safety Act prohibits th manufacture for sale, sale, offer for sale, introduction into interstate commerce, or importation of a vehicle which does not comply with all applicable standards in effect on the date of manufacture. (15 U.S.C. 1397(a)(1)(A)). However, the Act also provides that this prohibition no longer applies to a vehicle (except in the case of importation) after the first purchase of it in good faith for purposes other than resale. (15 U.S.C. 1397(b)(1)). The Act also prohibits any manufacturer, distributor, dealer, or motor vehicle repair business from knowingly rendering inoperative a safety device or design (15 U.S.C. 1397(a)(2)(A)).; These provisions mean that the manufacturer of the vehicle must assum responsibility for compliance and certification. Most trucks are built in several stages and completed by final-stage manufacturers like yourself. Cab-chassis are only incomplete vehicles which have not been certified, and therefore, whoever completes the vehicle and subsequently sells it or introduces it on the public highway must certify its compliance. In answer to your first question, it is the responsibility of the person who installs the fifth wheel, tractor protection system, etc., to certify compliance, whether or not the vehicle has been delivered to the first user. The owner himself would qualify as a final-stage manufacturer if he installed the conversion kit.; In answer to your third and fourth questions, the installation would b subject to certification unless it followed 'the first purchase of it in good faith for purposes other than resale.' 'Good faith' means that the first user could not, for example, buy a completed vehicle, drive it around the block and then install a non-conforming tag axle. Installation of a body after delivery to the first purchaser without compliance with Standard No. 121 would in most cases not appear to be good faith because the vehicle is not capable of use without the body.; It is permissible to make modifications to a vehicle that is already i service after the first purchase in good faith. A private party may make any change, but as noted above, a manufacturer, distributor, dealer, or motor vehicle repair business such as yours cannot 'knowingly render inoperative' a safety device in the process of modification. In answer to question number five, Standard No. 121 regulates the manufacture of new vehicles only and does not contain provisions which limit use of replacement parts. The only restriction in replacement would be to avoid knowingly rendering inoperative safety devices or design.; In answer to question number three, the standard establishe performance levels and does not contain any design requirements concerning the wiring harness of antilock systems. We would advise that you contact the antilock manufacturer or the vehicle manufacturer as to the wisdom of splicing antilock wiring.; For your information, I enclose a discussion of the standard whic addresses final-stage manufacture at page seven.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5070OpenMr. G. Thomas Owens Senior Engineering Representative Aetna Post Office Box 26283 Richmond, VA 23260-6283; Mr. G. Thomas Owens Senior Engineering Representative Aetna Post Office Box 26283 Richmond VA 23260-6283; "Dear Mr. Owens: This responds to your letter requesting informatio regarding the legal aspects of school bus safety standards. Specifically, you requested a book or pamphlet containing the requested information. By way of background information, under the provisions of the National Traffic and Motor Vehicle Safety Act of 1966, 15 U.S.C. 1381 et seq. (Safety Act), the National Highway Traffic Safety Administration (NHTSA) is authorized to promulgate Federal 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. In 1974 Congress enacted the Motor Vehicle and Schoolbus Safety Amendments of 1974 which, by amending section 121 of the Safety Act, directed the issuance of motor vehicle safety standards on specific aspects of school bus safety, applicable to all school buses. Those standards became effective on April 1, 1977 and are included, along with the rest of the agency's safety standards, in 49 CFR Part 571. The Safety Act defines a school bus as a vehicle that 'is likely to be significantly used for the purpose of transporting primary, preprimary, or secondary school students to or from such schools or events related to such schools.' NHTSA further defines a school bus as a motor vehicle designed for carrying eleven or more persons, including the driver, and sold for transporting students to and from school or school-related events. See 49 CFR 571.3. It is a violation of Federal law for any person knowingly to sell as a school bus any new vehicle that does not comply with all applicable Federal school bus safety standards. On the other hand, once a vehicle has been sold to the first purchaser for purposes other than resale, it may be used to transport school children without violating Federal law, even though it may not comply with Federal school bus safety standards. That is because individual states have the authority to regulate the use of vehicles. Therefore, to ascertain whether one may use noncomplying vehicles to transport school children, one must look to state law. It is this agency's position that vehicles meeting Federal school bus safety standards are the safest way to transport school children. Please find enclosed a pamphlet issued by this agency entitled Federal Motor Vehicle Safety Standards and Regulations, which summarizes our safety standards. Specifically, the following standards include requirements for school buses: Standards 101 through 104, Standard 105 (school buses with hydraulic brakes) Standards 106 through 108, Standards 111 through 113, Standard 115, Standard 116 (school buses with hydraulic service brakes), Standards 119 and 120, Standard 121 (school buses with air brakes), Standard 124, Standard 131 (effective September 1, 1992), Standards 201 through 204 (school buses with a gross vehicle weight rating (GVWR) of 10,000 pounds or less), Standard 205, Standards 207 through 210, Standard 212 (school buses with GVWR of 10,000 pounds or less), Standard 217, Standard 219 (school buses with GVWR of 10,000 pounds or less), Standard 220, Standard 221 (school buses with GVWR greater than 10,000 pounds), Standard 222, Standards 301 and 302. Some of the above-listed standards have unique requirements for school buses, including, but not necessarily limited to, Standards 105, 108, 111, 217, and 301. Other standards are applicable only to school buses, such as Standards 131, 220, 221, and 222. Standard 131 was promulgated on May 3, 1991 and may be found at 56 Federal Register 20370. It requires all school buses manufactured after September 1, 1992, to be equipped with stop signal arms. Standard 220 establishes requirements for school bus rollover protection. Standard 221 establishes strength requirements for school bus body panel joints. Standard 222 establishes minimum crash protection levels for occupants of school buses. Under the provisions of Standard 222, small school buses, that is those with a GVWR of 10,000 pounds or less, must be equipped with lap belts. For large school buses, those with a GVWR greater than 10,000 pounds, the standard requires occupant protection through 'compartmentalization,' a concept which calls for strong, well-padded, well-anchored, high-backed, evenly spaced seats. Should you wish copies of our safety standards, I am enclosing for your information a fact sheet prepared by this office entitled Where to Obtain NHTSA's Safety Standards and Regulations. I hope this information is helpful. If you have further questions in this regard, please feel free to contact Mr. Walter Myers of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosures"; |
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ID: aiam0788OpenMr. Walter Sniff, Quality Control Manager, Crown Steel Products Division, 1330 North Main Street, Orrville, OH, 44667; Mr. Walter Sniff Quality Control Manager Crown Steel Products Division 1330 North Main Street Orrville OH 44667; Dear Mr. Sniff: This is in reply to your letter of June 30, 1972, concerning Moto Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' asking for a determination of the term 'passenger compartment' in a van-type vehicle that has either a partial partition behind the driver's seat or no partition at all.; We would consider a reasonable interpretation of the phrase 'occupan compartment' found in S1 of the Standard, when applied to van-type trucks which have no physical barrier between the occupant and cargo compartments, to be that area forward of a vertical plane perpendicular to the longitudinal centerline of the vehicle and tangent to the rearmost point of any occupant seat in its rearmost position. In the case where there is a partial partition behind the driver's seat, we would consider the 'occupant compartment' to be that area forward of a vertical plane that constitutes an extension of the partial partition and is perpendicular to the longitudinal centerline of the vehicle. The cargo areas of such vehicles would not be considered 'vehicle occupant compartments' under S4.1 of the Standard, and the materials used in the cargo area need not comply with the Standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0272OpenMr. Harry B. Mitchell, Jr., President, Mitchell & Sons, Inc., 5961 E. 64th Avenue, Commerce City, CO 80022; Mr. Harry B. Mitchell Jr. President Mitchell & Sons Inc. 5961 E. 64th Avenue Commerce City CO 80022; Dear Mr. Mitchell: This is in response to your letter of December 16, 1970, requesting clarification of our October 8, 1970 letter on the subject of the compliance of your campers with Standard No. 206.; The second paragraph in our letter was intended to apply to both you 14-foot 6-inch and 12-foot 6-inch campers and should have read as follows: 'You are correct in stating that the door in camper bodies built according to either of the floor plans enclosed with your letter would not be required to comply with Standard No. 206 if, as it appears, no portion of a manikin positioned at any seating reference point would project into the door opening area.' Of course, it is your responsibility under the National Traffic and Motor Vehicle Safety Act to determine whether both types of your campers actually meet the provisions of that paragraph.; Please write if we can be of further assistance. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam4548OpenMr. Gary M. Ceazan Vice President Riken-America, Inc. PO Box 3698 Terminal Annex Los Angeles, CA 90051; Mr. Gary M. Ceazan Vice President Riken-America Inc. PO Box 3698 Terminal Annex Los Angeles CA 90051; "Dear Mr. Ceazan: This is in response to your letter asking whethe tires marked with both an ETRTO (European Tyre and Rim Technical Organization) size designation and a different ISO (International Standardization Organization) size designation can legally be imported into the United States. As discussed below, such tires cannot be imported into the United States, because they do not comply with the applicable safety standards. I regret the delay in this response. All new pneumatic tires imported into the United States for use on passenger cars must be certified as complying with Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires - Passenger Cars (49 CFR /571.109), and all new pneumatic tires imported for use on motor vehicles other than passenger vehicles must be certified as complying with Standard No. 119, New Pneumatic Tires for Vehicles Other Than Passenger Cars (49 CFR /571.119). Both of these standards prohibit 'dual-size markings,' or labeling two different size designations on one tire. In the case of passenger car tires, section S4.3(a) of Standard No. 109 specifies that each tire shall be labeled with 'one size designation, except that equivalent inch and metric size designations may be used.' (emphasis added). This agency expressly prohibited dual-size markings on passenger car tires in a preamble amending Standard No. 109, 36 FR 1195, January 26, 1971. This prohibition was expressly repeated in subsequent amendments that addressed the question of tire labeling under Standard No. 109, see 39 FR 10162, March 18, 1974, and 42 FR 12869, March 7, 1977. In the case of tires for use on vehicles other than passenger cars, there is no express prohibition in Standard No. 119 against dual size markings. However, section S6.5(c) of Standard No. 119 requires that each tire be marked on both sidewalls with 'the tire and size designation as listed in the documents and publications designated in S5.1.' NHTSA has interpreted the use of the singular in the phrase 'tire size designation,' rather than the plural 'tire size designations,' to be a prohibition against marking more than one tire size designation on these tires. See the enclosed copies of my January 7, 1988 letter to Mr. E.W. Dahl and my February 16, 1988 letter to Mr. Mike Kaizaki. Since tires marked with two size designations would not comply with our tire standards, they could not legally be imported into the United States, according to the requirement specified in section 108(a)(1)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(1)(A)). If you have any further questions about our tire standards or need additional information on this subject, please feel free to contact Mr. Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel Enclosures /"; |
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ID: aiam2865OpenMr. Robert B. Kurre, Director of Engineering, Wayne Corporation, P. O. Box 1447, Industries Road, Richmond, IN 47374; Mr. Robert B. Kurre Director of Engineering Wayne Corporation P. O. Box 1447 Industries Road Richmond IN 47374; Dear Mr. Kurre: This responds to your recent letter asking whether Safety Standard No 208 applies to side-facing seats in multi-purpose passenger vehicle vans. You also ask to be advised of the criteria to be used for the installation of seat belts in these vehicles.; Safety Standard No. 208, *Occupant Crash Protection*, does requir side-facing seats in multipurpose passenger vehicles to comply with one of the options under paragraph S4.2.2, since the side-facing seats in question would be considered designated seating positions. If a manufacturer chooses to install seat belts under one of the options of that paragraph, the seat belt assemblies must comply with Safety Standard No. 209, *Seat Belt Assemblies*, and Safety Standard No. 210, *Seat Belt Anchorages*.; Safety Standard No. 210 does exempt side-facing seats from its strengt requirements, but all other requirements of the standard would be applicable. However, we strongly recommend that belt anchorages for side- facing seats be of at least equivalent strength to anchorages for forward and rearward facing seats, since the strength specifications are only minimum performance requirements. Side-facing seats were excepted from the strength requirements specified in the standard because the forces acting on side-facing seats are different from those acting on forward or rearward facing seats and the requirements and procedures were specifically developed for these latter seats.; Please contact this office if you have any further questions. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0858OpenMr. William E. McSherry, Product Manager, Panduit Corporation, 17301 Ridgeland Avenue, Tinley Park, IL, 60477; Mr. William E. McSherry Product Manager Panduit Corporation 17301 Ridgeland Avenue Tinley Park IL 60477; Dear Mr. McSherry: This is in reply to your letter of August 10, 1972, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials', to the nylon cable ties you manufacture.; Paragraph S4.1 of the Standard does not include nylon cable ties o their equivalent and, accordingly, these components are not subject to the requirements of the Standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3777OpenMr. J. Wuddel, Westfalische Metall Industrie KG, Hueck & Co., Postfach 28 40, 4780 Lippstadt, Germany; Mr. J. Wuddel Westfalische Metall Industrie KG Hueck & Co. Postfach 28 40 4780 Lippstadt Germany; Dear Mr. Wuddel: This is in reply to your letter of September 23, 1983, to Augus Burgett of this agency with respect to an illuminated plate positioned between the right and left rear lamps. The plate would be illuminated by a separate light source, and would 'expose the manufacturer's name and the vehicle type.' You have asked if such a plate would be allowed on the rear of the vehicle.; Paragraph S4.1.3 of Federal Motor Vehicle Safety Standard No. 10 prohibits the installation of any motor vehicle equipment that impairs the effectiveness of lighting equipment required by Standard No. 108. Each lamp on the rear of a motor vehicle under Standard No. 108 serves an informational purpose, either to mark the vehicle (taillamps, license plate lamps, hazard warning signals) or to indicate vehicle action (stop lamps, turn signal lamps, backup lamps). It is imperative for purposes of safety that the function of each rear lamp be clearly understood by drivers following the vehicle. Addition of a light source or lamp other than that required by Standard No. 108 contains the potential either for confusion or to mask the effect of one of the required lighting devices. In general, the agency is opposed to any lighting devices on the rear of vehicles other than those required by the standard.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4118OpenMr. Jost Leite, Hanover Marketing & Trade Corporation, 1703 N.W. 38th Avenue, Lauderhill, FL 33311; Mr. Jost Leite Hanover Marketing & Trade Corporation 1703 N.W. 38th Avenue Lauderhill FL 33311; Dear Mr. Leite: This responds to your letters to this office which, in effect, aske about a manufacturer's certification responsibilities and who has the authority to determine a product does not comply with an applicable Federal motor vehicle safety standard. I regret the delay in our response. I hope the following discussion answers your questions.; The National Traffic and Motor Vehicle Safety Act establishes self-certification requirement for manufacturers. Thus, it is the responsibility of each manufacturer to certify that its products are in compliance. Under the Act, only the manufacturer of the product or the agency can formally determine that a product is not in compliance and commence a notification and remedy campaign.; The public is encouraged to notify this agency if they believe potential noncompliance exists in a particular product. The agency will, if appropriate, begin a compliance investigation. However, this agency could not and has not authorized any member of the private industry to conduct compliance investigations.; I hope this responds to your concerns. Please contact my office if yo have further questions.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3327OpenMr. Robert P. Spena, D.S.W., Director, Bureau of Traffic Safety Operations, Department of Transportation, Commonwealth of Pennsylvania, Harrisburg PN 17123; Mr. Robert P. Spena D.S.W. Director Bureau of Traffic Safety Operations Department of Transportation Commonwealth of Pennsylvania Harrisburg PN 17123; Dear Mr. Spena: This is in reply to your letters of July 18, 1980, to the Administrato and myself and confirms a telephone conversation between Dr. Devin of your office and Taylor Vinson of ours, on August 5, 1980.; You have asked the following questions: '1. Does any Federal Regulation addresss (sic) the issue of intermixin motorcycle and other motor vehicle parts?'; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 *e seq*.), a copy of which I enclose, is the authority for Federal regulation of the manufacture of motorcycles and other motor vehicles. The Federal motor vehicle safety standards (49 CFR Part 571) implement the Act.; Neither the Act nor the Standards directly address the issue of th intermixing of parts of motorcycles and other motor vehicles. However, use of one half of a passenger car headlighting system is permitted as a motorcycle headlighting system (see paragraph S4.1.1.34 of 49 CFR 571.108). As a general rule, under the Act and Standards use of motorcycle equipment as original equipment on passenger cars and other motor vehicles is not prohibited unless such use creates a noncompliance with any Federal motor vehicle safety standard applicable to the vehicles or a defect related to motor vehicle safety.; In addition, section 108(a) (2) (A) of the Act prohibits an 'manufacturer', 'distributor', 'dealer', or 'motor vehicle repair business' from rendering inoperative in whole or in part any device or element of design installed on a vehicle in accordance with a Federal motor vehicle safety standard. We interpret this as forbidding anyone but the owner of a vehicle in use from removing and substituting original vehicle equipment if it results in a noncompliance. This prohibition has at least a theoretical application to the intermixing of vehicle parts.; '2. Can NHTSA provide any suggestions, recommendations or guidance o this matter?'; We are unable to be helpful because few instances of intermixing cam to mind. We are currently in litigation with an importer of European passenger car headlamps that are purportedly certified only to 'motorcycle' requirements but which, in fact are being sold for use on passenger cars. This would not appear to be a true instance of intermixing since there appears to be little market for them as motorcycle headlamps. Generally, however, it would not appear sound practice to use equipment in an application not intended by its manufacturer.; '3. We would also like to know your position on 'kit cars''. There are no regulations or standards applicable to 'kit cars' per se nor do we even have a definition of the term. But some general principles apply under the Act nonetheless.; The classic 'kit car' operation involves the removal of an old vehicl body from its chassis and its replacement with a new one. The resulting assemblage retains the title of the vehicle's original incarnation. As the Act defines a 'manufacturer' to include one who assembles motor vehicles, a person in the business of assembling kit cars bears the manufacturer's statutory responsibility (15 U.S.C. 1411 *et seq*.) for notification and remedy in the event his assembly operations create a safety related defect in the vehicle.; A newly-assembled vehicle using its previous title is considered 'used and does not have to comply with the safety standards that apply to 'new' vehicles. However, we interpret Section 108(a) (2) (A), discussed in response to your first question, as requiring the assembler, if it is the party removing the old body, to insure that the vehicle upon completion of reassembly had it been originally manufactured with the new body meet the standards with which it would have complied. For example, if a new fiberglass convertible body is mounted on the chassis of a 1972 Volkswagen Beetle, the vehicle must meet all standards that apply to 1972 convertibles. If it does not, its assembler as a 'manufacturer' appears to be obligated under the Act to notify purchasers and remedy the noncompliances.; Some of the safety standards apply to individual equipment items suc as tires, lighting equipment, glazing and seat belts. Any item covered by a Federal equipment standard and supplied in the kit must meet such standard.; Outside this framework our position is necessarily determined by th facts of each use but generally, the greater the number of new parts used in a vehicle, the more likely we are to consider it as one which must meet the standards that apply to new vehicles.; If you have any further questions Mr. Vinson will be happy to answe them (202-426-9511).; Sincerely, Frank Berndt, Chief Counsel |
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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.