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: aiam1780OpenMr. Byron Crampton, Truck Body & Equipment Assoc., 5530 Wisconsin, (sic) Ave., Suite 1220, Washington, DC 20015; Mr. Byron Crampton Truck Body & Equipment Assoc. 5530 Wisconsin (sic) Ave. Suite 1220 Washington DC 20015; Dear Mr. Crampton: This responds to your January 3, 1975, question whether a firefightin vehicle which articulates and has a configuration similar to that a conventional truck-trailer combinations qualifies as a 'truck' for test purposes under Standard No. 121, *Air brake systems*. You describe the vehicle as a tractor trailer aerial ladder with articulating portions that cannot be uncoupled, and with permanently-connected air brake lines and hydraulic pressure lines between the articulating sections.; The vehicle you describe is a 'truck' as that term is defined in 49 CF S 571.3, *Definitions*. The rear articulated portion does not qualifiy (sic) as a 'trailer' as defined in S571.3, because the permanent connection to the truck tractor prevents it from standing alone as a 'vehicle'. Therefore, the tractor trailer aerial ladder would be tested as a truck under Standard No. 121. It is noteworthy that the lighting requirements which apply to the rear portion of this vehicle are those for trucks under Standard No. 108, *Lamps reflective devices, and associated equipment*.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4078OpenThe Honorable Don Sundquist, Member, U.S. House of Representatives, 5909 Shelby Oaks Drive, Suite 112, Memphis, TN 38134; The Honorable Don Sundquist Member U.S. House of Representatives 5909 Shelby Oaks Drive Suite 112 Memphis TN 38134; Dear Mr. Sundquist: This is in response to your inquiry on behalf of Josephine Jackson, th president of the Tennessee County Clerk's Association, who is concerned about the burden placed on the clerks by motor vehicle odometer disclosure requirements. Specifically, the Association has approved a resolution requesting the exemption of vehicles more than seven years old from the Federal odometer disclosure requirements. We can understand the concern which led the Association to pass the resolution.; The Federal odometer law (15 U.S.C. SS 1981-1991) requires each perso who transfers ownership of a motor vehicle to disclose the vehicle's mileage. The law does not exempt older vehicles from this requirement.; In support of its resolution, the Association notes that many olde vehicles either have nonworking odometers or have travelled beyond 99,999 miles, making the actual mileage hard to verify. This is correct in our experience, and the Federal law therefore provides that, in cases where he has reason to know that the reading is inaccurate, either through inspection of the vehicle or paperwork, the owner may state that the actual mileage is unknown.; The Association's resolution states further that most purchasers o older vehicles are not concerned with mileage, but with the condition of the vehicle. In developing our regulation on odometers, we had accepted this view for vehicles of extreme age, and had, therefore, exempted vehicles 25 years old or older. However, several Federal District Courts have subsequently questioned our authority to grant exemptions under current law. Although the Department has supported measures in pending legislation to improve odometer enforcement by making odometer fraud a felony, we have taken no position as to whether the exemption of older vehicles by law would be advisable.; I hope that you will find this information helpful in responding to th Association.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam0892OpenMr. R. A. C. Dandy, Senior Engineer, Head of Mechanical Section, British Standards Institution, Hemel Hempstead Centre, Maylands Avenue, Hemel Hempstead, Herts, England; Mr. R. A. C. Dandy Senior Engineer Head of Mechanical Section British Standards Institution Hemel Hempstead Centre Maylands Avenue Hemel Hempstead Herts England; Dear Mr. Dandy: This is in reply to your letter of September 25, 1972, concerning th application of S4.3(c) of Standard No. 209 to an upper torso anchorage bolt used to attach a seat belt assembly that has a continuous length of webbing for upper torso and pelvic restraint.; Our letter of July 20, 1972, to Standard Triumph, to which you refer did not rule directly on the question of whether a bolt on the upper torso side of a continuous loop assembly would be considered to secure the pelvic restraint' within the meaning of S4.3(c). It is our opinion that some part of the pelvic force is transmitted to such a bolt and that it is therefore required to conform to S4.3(c). Because the bolt cannot be used for more than one assembly, the applicable force requirement is 5,000 pounds.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4582OpenMr. Keith E. Madden Research Associate College of Engineering Department of Chemical and Materials Engineering 125B Chemistry Building The University of Iowa Iowa City, Iowa 52242; Mr. Keith E. Madden Research Associate College of Engineering Department of Chemical and Materials Engineering 125B Chemistry Building The University of Iowa Iowa City Iowa 52242; "Dear Mr. Madden: This is in reply to your letter of February 3, l989 with respect to importation of ethanol-fueled trucks from Brazil. You have requested assurance that 'there are no legal or administrative roadblocks to this importation.' I am happy to provide the assurance you seek. Your letter indicates that you are well versed in our importation procedures, and that you have discussed this matter with Messrs. VanOrden and Vinson of this agency. The University of Iowa is permitted to import trucks that do not comply with all applicable Federal motor vehicle safety standards for purposes of test and experimentation, pursuant to Title l9, Code of Federal Regulations, Section 12.80(b)(i)(vii). When the trucks reach the United States, the importer of record makes the appropriate declaration (in this instance, Box 7 of the HS-7 Form). If vehicles imported for testing and experimenting will be used on the public roads, the importer must attach a sheet to the Form stating the purpose for which the vehicles are imported, the estimated amount of time that the vehicles will be used on the public road, and whether after testing they will be exported, abandoned to the United States, or brought into compliance. Permission for the noncomplying vehicles to remain in the United States for the purposes of testing and experimenting is renewable annually for a maximum total of three years. Thus, for example, at the end of the first year, if the importer requires more time for on-road testing, it must write this Department of that need. Generally, permission is granted for an additional year. If a third year is needed for on-road testing, the importer must again request permission of this agency. We see no legal or administrative impediments to this importation. Further, under these circumstances, the Brazilian manufacturer of these trucks has no responsibilities to the Department of Transportation under any of its laws or regulations. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam3247OpenMr. Samuel W. Halper, Bartman, Braun and Halper, Suite 1015, 1880 Century Park East, Los Angeles, CA 90067; Mr. Samuel W. Halper Bartman Braun and Halper Suite 1015 1880 Century Park East Los Angeles CA 90067; Dear Mr. Halper: This responds to your letter of March 13, 1980, on behalf of Californi Strolee, Inc., concerning Standard No. 213, *Child Restraint Systems*.; You asked whether a 'foam tray' marketed as an accessory for a chil restraint by Strolee is prohibited by section S5.2.2.2 of the standard. According to your description, the tray 'may be affixed to the car seat by straps and velcro fasteners' and is made of polyurethane foam and 'does not contain any metal or solid parts.' The purpose of the device is 'to give a child a surface on which to play or to put things during car rides.'; Section S5.2.2.2 prohibits any fixed or movable surfaces in front o the child except for surfaces that adequately restrain the test dummy in the 20 mph test. If the foam tray attaches to the child restraint so that it is the only surface in front of the child, the child restraint would have to be tested with just the tray as specified in Section S5.2.2.2. If the foam tray is attached to a surface that complies with S5.2.2.2, such as a padded shield, a separate test using the foam tray alone would not be required.; You also raised a question about section S6.1.2.1.2. You explained tha Strolee is considering the use of 'an impact shield designed to go across the front of the car seat to restrain the child.' The impact shield 'would be removable and it would be recommended that it not be used when the car seat is in the rearward facing mode.' When the restraint is used in a rear-facing position, the child is to be restrained by a five-point belt system. You asked if the Strolee seat would be required to be tested under Test Configuration II in a rear-facing position.; The answer is no. Section S6.1.2.3.2 provides that each fixed o movable surface is to be positioned in accordance with the manufacturer's instructions prior to the testing required by S6.1.2.1.2. Thus, if the instructions inform users that the removable shield is not to be used in a rear-facing position, then the restraint need not be tested at 20 mph in a rear-facing position. The restraint would be tested at 20 mph in the forward-facing position with the shield in place but with none of the restraint system belts fastened, unless they are an integral part of the shield.; You also asked about obtaining copies of interpretations issued by th agency. The agency's docket section maintains a file of the interpretations for each standard and can provide you with copies. The address is: Docket Section, Room 5108, 400 Seventh Street, S.W., Washington, D.C. 20590.; If you have any further questions, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2285OpenMr. Tokio Iinuma, Staff, Safety, Nissan Motor Co., Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Tokio Iinuma Staff Safety Nissan Motor Co. Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Iinuma: This is in response to your letter of March 17, 1976, inquiring as t the date on which a manufacturer will no longer have to comply with State bumper standards relating to property damage.; According to section 110 of the Motor Vehicle Information and Cos Savings Act (Pub. L. 92-513) once a Federal bumper standard takes effect 'no State or political subdivision thereof shall have any authority to establish or enforce with respect to any passenger motor vehicle or passenger motor vehicle equipment offered for sale any bumper standard which is not identical to' the Federal standard. The Part 581 bumper standard becomes effective September 1, 1978. As of that date, it preempts any State bumper standard which is not identical. Even though the standard becomes effective in stages, on September 1, 1978 (S5.1) and September 1, 1979 (S5.2), the preemptive effect is complete on the earlier date, September 1, 1978. Thus, a vehicle manufactured on or after September 1, 1978, and before September 1, 1979, will not have to meet a State standard, even though the State standard may be identical to the requirements of the Federal standard that become (sic) effective on September 1, 1979.; The National Highway Traffic Safety Administration proposed on Marc 12, 1976, to allow manufacturers to comply with the requirements of Part 581 before the mandatory September 1, 1978, effective date. If this proposal becomes final, any manufacturer who chooses to comply early with Part 581 and properly certifies his compliance will not be required to satisfy any non-identical State bumper standard. For purposes of that manufacturer, the Part 581 Federal bumper standard will be in effect.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam5540OpenMr. Musa K. Farmand Gonz lez & Farmand, P.A. 555-B Blanding Boulevard Orange Park, FL 32073; Mr. Musa K. Farmand Gonz lez & Farmand P.A. 555-B Blanding Boulevard Orange Park FL 32073; "Dear Mr. Farmand: This responds to your letter of April 27, 1995. You letter concerns a law suit in which you represent plaintiffs injured in an automobile accident. In this law suit, the counsel for the defendant has moved to amend his answer to assert that 49 CFR 571.208, paragraph S4.1.5.2(c)(2) requires each state to allow for mitigation of damages in any seat belt use law and that paragraph preempts the Florida mandatory seat belt law. According to your letter, the Florida law 'does not allow a mitigation of damages defense with respect to an alleged failure to wear a seat belt.' As explained below, the National Highway Traffic Safety Administration agrees with you that the Florida safety belt use law is neither expressly nor impliedly preempted by Federal law. Purpose of Paragraph S4.1.5.2(c)(2) Before discussing the issue of preemption, I want to discuss the background and purpose of Paragraph S4.1.5.2(c)(2). That paragraph was added to Standard No. 208, Occupant Crash Protection (49 CFR 571.208) as part of a final rule issued July 17, 1984 concerning automatic restraints (49 FR 28962). That final rule required all new cars to have automatic protection (air bags or automatic belts) starting in the 1990 model year. The final rule included a provision that the automatic restraint requirement would be rescinded if the Secretary of Transportation determined, not later than April 1, 1989, that a sufficient number of States had enacted belt use laws meeting certain minimum criteria to cover at least two-thirds of the U.S. population (paragraph S4.1.5). Under S4.1.5, the Secretary was not required to make any determination about any State safety belt laws. In fact, the Secretary never did so, in part because not enough States adopted mandatory seat belt use laws of any sort prior to April 1, 1989. Because no determination was made under S4.1.5, the automatic restraint requirements are now in effect for all passenger cars. The minimum criteria were set forth in S4.1.5.2 of Standard No. 208. One of the criteria was 'a provision specifying that the violation of the belt usage requirement may be used to mitigate damages...' (S4.1.5.2(c)(2)). However, S4.1.5 neither purported to require nor was intended to require States to enact safety belt use laws. In addition, S4.1.5 did not require that any State safety belt use laws had to incorporate the minimum criteria of S4.1.5.2. Paragraph S4.1.5 merely provided that the Secretary would rescind the automatic restraint requirement if he or she determined that a sufficient number of States enacted laws which met the criteria of S4.1.5.2 by April 1, 1989. Preemption The Florida safety belt use law is not and never has been either expressly or impliedly preempted by Federal law. Standard No. 208 was issued under 49 U.S.C. Chapter 301 which expressly preempts state laws only to the extent provided by section 30103. That section provides for the express preemption of State motor vehicle safety standards that are not identical to Federal standards. However, the Florida seat belt law is not a motor vehicle safety standard within the meaning of Chapter 301, since it does not regulate motor vehicle or motor vehicle equipment performance. Accordingly, the Florida law is not expressly preempted. The Florida law is not impliedly preempted because (1) Congress has not occupied the field of regulation of the behavior of motor vehicle occupants, and (2) the Florida seat belt law does not conflict with any Federal law or interfere with the objectives of Federal law. I hope this information has been helpful. If you have other questions or need some additional information, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam1850OpenMr. Robert Marx, State Representative, District #34, Polk- Benton, House of Representatives, Salem, OR 97310; Mr. Robert Marx State Representative District #34 Polk- Benton House of Representatives Salem OR 97310; Dear Mr. Marx: This is in response to your letter of March 10, 1975, requestin information concerning correspondence from one of your constituents, Mr. Jim Lee Martin, commenting on a proposed amendment to the Federal 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 be increased to 4 mph for 1979 and later model year cars.; The proposal was based primarily on the results of two agency sponsored 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 on March 12, 1975 (Docket No. 74-11, Notice 7, Docket No. 73-19, Notice 6).; Mr. Martin has directed his comments to what he believes to be 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 (plastic) 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.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0742OpenMr. Ed Burnett, Recreational Vehicle Institute, Inc., Suite 406, 1140 Connecticut Avenue, Washington, DC, 20006; Mr. Ed Burnett Recreational Vehicle Institute Inc. Suite 406 1140 Connecticut Avenue Washington DC 20006; Dear Mr. Burnett: This is in further reply to Mr. David Humphrey's letter of April 25 1972, concerning the application of Motor Vehicle Safety Standard No. 302 to motor homes. Certain items, namely molded plastic toilets, shower stalls, and bath tubs were inadvertently omitted from our reply of May 16, 1972.; With respect to toilets, the NHTSA considers toilets (and toilet seats to fall within the meaning of seat backs and seat cushions in paragraph S4.1, of Standard No. 302 and consequently to be subject to the standard. Shower stalls and bath tubs are not included in the list of components in S4.1, and are not subject to the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5110OpenMr. Daniel Cassese 28 Elva Road N. Weymouth, MA 01291; Mr. Daniel Cassese 28 Elva Road N. Weymouth MA 01291; "Dear Mr. Cassese: This responds to your letter of November 19, 1992 Your letter describes your invention called a 'Head Rest Extension.' You asked if this invention would comply with Federal Motor Vehicle Safety Standards Nos. 201, 202, and 208. By way of background information, the National Traffic and Motor Vehicle Safety Act (the Safety Act, 15 U.S.C. 1381 et seq.) authorizes this agency to issue Federal motor vehicle safety standards applicable to new motor vehicles and new items of motor vehicle equipment. Section 108(a)(1)(A) of the Safety Act (15 U.S.C. 1397(a)(1)(A)) prohibits any person from manufacturing, introducing into commerce, selling, or importing any new motor vehicle or item of motor vehicle equipment unless the vehicle or equipment item is in conformity with all applicable safety standards. 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. NHTSA has exercised its authority to establish four safety standards which could be relevant to a head rest extension: Standard No. 201, Occupant Protection in Interior Impact, Standard No. 202, Head Restraints, Standard No. 208, Occupant Crash Protection, and Standard No. 302, Flammability of Interior Materials. These four standards apply only to new vehicles, not to items of individual equipment. If the head rest extension were installed before the vehicle's first purchase for purposes other than resale, the vehicle would have to be certified as complying with all applicable standards, including these four, with the head rest extension installed. However, as you have explained in a phone conversation with Mary Versailles of my staff, your product is intended to be an item of after-market equipment. After a vehicle's first purchase for purposes other than resale, i.e., the first retail sale of the vehicle, the only provision in Federal law that affects a vehicle's continuing compliance with an applicable safety standard is set forth in section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section provides that: No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle ... in compliance with an applicable Federal motor vehicle safety standard. Any violation of this 'render inoperative' prohibition would subject the violator to a potential civil penalty of up to $1,000 for each violation. Please note that the 'render inoperative' prohibition does not require manufacturers, distributors, dealers, and repair businesses to certify that vehicles continue to comply with the safety standards after any aftermarket modifications are made. Instead, 'render inoperative' prohibits those entities from performing aftermarket modifications that they know or should know will result in the vehicle no longer complying with the safety standards. Please note also that the 'render inoperative' prohibition does not apply to modifications vehicle owners make to their own vehicles. Thus, Federal law would not apply in situations where individual vehicle owners install your head rest extension in their own vehicles, even if the installation were to result in the vehicle no longer complying with the safety standards. However, individual States have the authority to regulate modifications that individual vehicle owners may make to their own vehicles. You should also note that a head rest extension would be considered 'motor vehicle equipment' within the meaning of the Safety Act. Therefore, if it contained a defect (either in manufacture, design, or performance) that relates to motor vehicle safety, you would be required to conduct a recall campaign to notify owners and to remedy the defect free of charge. I have enclosed an information sheet for new manufacturers of motor vehicle equipment that briefly explains the responsibilities imposed on manufacturers, and tells how to get copies of the relevant laws and regulations. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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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.