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: aiam4569OpenMr. Leonard M. Perkins 213 S. Pleasant Prescott, AZ 86303; Mr. Leonard M. Perkins 213 S. Pleasant Prescott AZ 86303; Dear Mr. Perkins: Secretary Burnley has asked me to respond to you letter of September 7, 1988, with respect to your lighting device. In essence, this is a center high-mounted stop lamp, with turn signal lamps adjacent to it. You believe that high-mounted turn signals 'joined with the rear window brake light should have a dramatic effect on rear and side collisions', but you have been told that 'this conception is at present illegal.' Paragraph S4.4 of Federal Motor Vehicle Safety Standard No. 108 states that 'no high-mounted stop lamp shall be combined with any other lamp or reflective device.' We interpret this as prohibiting lamps or reflective devices that share a single lens or compartment with the center highmounted lamp. Your device shows lamps adjacent to the center highmounted lamp but not combined with it. Therefore, your device is not prohibited by that paragraph of the standard if you wish to market this device as original equipment. The next question to ask is whether it impairs the effectiveness of required lighting equipment (paragraph S4.1.3), principally the center stoplamp. For example, if the yellow turn signals were too bright or if the color of the turn signal were red, these lamps might 'impair the effectiveness' of the center stoplamp. However, this is a determination to be made, in the first instance, by the manufacturer of the vehicle who must certify compliance with Standard No. 108. If you wish to sell your device in the aftermarket, it is acceptable under Federal law if its installation does not adversely affect the operation of motor vehicle equipment installed in accordance with a Federal motor vehicle safety standard so that the equipment would no longer comply with the standard. Assuming that the installation does not have this effect, the legality of installing or using such a device must then be determined according to the laws of any State in which a vehicle so equipped is registered or operated, and these auxiliary lamps must comply with any State requirements. We cannot advise you on State laws. One source of advice is the American Association of Motor Vehicle Administrators, 4600 Wilson Blvd., Arlington, Va. 22203. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1291OpenMr. William G. Mathews III, National Sales Manager, Marchal America, 14622 Southlawn Lane, Rockville, MD 20850; Mr. William G. Mathews III National Sales Manager Marchal America 14622 Southlawn Lane Rockville MD 20850; Dear Mr. Mathews: This responds to your letter No. 8495, dated October 5, 1973, to th National Highway Traffic Safety Administration concerning the legality of an automotive headlamp having a sealed metal reflector, glass lens arrangement. It is understood from your letter that such a headlamp would meet all requirements of Federal Motor Vehicle Safety Standard No. 108, including photometric and electrical performance, interchangeability and mechanical aiming.; Specifically your question is: 'Would a hermetically sealed metal an glass headlamp, (one in every way interchangeable with existing approved sealed beams except that the reflector would be metal instead of glass), be acceptable under current federal regulations?'; The answer to your question is 'yes.' Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam2844OpenHoward E. Chase, Esq. Singer, Hutner, Levine and Seeman 110 East 59th Street New York, NY 10022; Howard E. Chase Esq. Singer Hutner Levine and Seeman 110 East 59th Street New York NY 10022; Dear Mr. Chase: This is in response to your April 6, 1978, lette regarding the eligibility of Officino Alfieri Maserati, S.p.A. (Maserati) to apply for an exemption from the generally applicable average fuel economy standards under the Motor Vehicle Information and Cost Savings Act, as amended. You concluded that Maserati was eligible for this exemption although it is under common control with another company, Nuova Innocenti S.p.A. (Innocenti), whose annual production of passenger automobiles exceeds 10,000 passenger automobilies. I agree with your conclusion for the reason set forth below. The requirements concerning eligibility for an exemption under the Act are set forth in section 502(c), which provides: On application of a manufacturer who manufactured (whether or not in the United States) fewer than 10,000 passenger automobiles in the second model year preceding the model year for which the application is made, the Secretary may, by rule, exempt such manufacturer from subsection (a). To determine whether Maserati manufactures fewer than 10,000 passenger automobiles, it is necessary to interpret and apply sections 501(9) and 503(c) of the Act. Section 501(9) provides: 'The term 'manufacturer' (sic) (except for purposes of section 502 (c) means to produce or assemble in the customs territory of the United States, or to import.' Section 503(c) provides: (c) Any reference in this part to automobiles manufactured by a manufacturer shall be deemed- - (1) to include all automobiles manufactured by persons who control, are controlled by, or are under common control with, such manufacturer, and (2) to exclude all automobiles manufactured (within the meaning of paragraph (1)) during a model year by such manufacturer which are exported prior to the expiration of 30 days following the end of such model year. If sections 501(9) and 502(c) were considered together and section 503(c) were excluded from consideration, it is clear that Maserati would be eligible for an exemption, since Maserati's annual worldwide production is well under 10,000 automobiles. The key question, as you observed, involves section 503(c)- The question is whether 'manufacture' in section 503(c), as that section applies to section 502(c), means 'to produce or assemble in the customs territory of the United States, or to import' or means 'to produce or assemble, regardless of the geographical location of the act.' The former, restricted definition is given in section 501(9) and applies, except for the purposes of section 502(c), to all Title V. The latter, unrestricted definition is derived from the phrase 'manufactured (whether or not in the United States)' in the first sentence of section 502(c) and applies for the purpose of that section. I believe that 'manufacture', as used in section 503(c), has the restricted meaning. As I interpret the phrase 'for the purposes of section 502(c),' 'manufacture' has the unrestricted meaning only in section 502(c) and even there not in every instance. Thus, the Innocenti automobiles are not counted together with the Maseratis for the purposes of determining eligibility for an exemption under section 502(c). The Innocenti automobiles would be added to Maseratis only if the Innocentis were 'manufactured' in the restricted sense, that is, if the Innocentis were imported into the United States. Since the Innocenti automobiles are not counted with Maserati's, Maserati is eligible for an exemption from the generally applicable average fuel economy standard. This agency will begin processing your petition immediately. If you have any further questions on this matter, please contact Stephen Kratzke of the Office of Chief Counsel at (202) 426-2922. Sincerely, Howard Dugoff Deputy Administrator; |
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ID: aiam0879OpenMr. Satoshi Nishibori, Engineering Representative, Nissan Motor Co., Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Satoshi Nishibori Engineering Representative Nissan Motor Co. Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Nishibori: This is in reply to your letter of September 18, 1972, on the subjec of warning system and interlock system operation under Standard No. 208.; The table enclosed with your letter lists all combinations of fron seat occupancy and front seat belt usage that are possible in a vehicle with two front seating positions. You ask, as to each of these combinations, whether you have correctly understood the operation of the interlock and warning system. We find that a large majority of the combinations shown in your table are correctly interpreted but that a few are in error or are in need of further clarification.; The primary source of error in the table seems to be confusion as t the effect of the driver's absence from his seat. Under S7.4.1, the conditions under which a failure to operate the belt will require the interlock system to prevent engine operation are specified in S7.4.1(a) and (b). Each of these conditions specifies that the driver's position is occupied, so that if the driver is not in his seat neither condition (a) nor condition (b) is met and interlock system operation is not required.; Applying this interpretation to the matrix in your table discloses tha two cases, 18 and 25, are incorrectly interpreted. In each of these cases the driver is not in his seat and the interlock would not be required to operate, even though in both cases the passenger has operated his belt out of sequence and in one case the belt at the vacant driver's position is buckled.; Although interlock operation is not required in cases 18 and 25, manufacturer would be permitted to design his interlock system to operate in these circumstances. Eighteen and 25 should therefore be treated in the same manner as the other cases in the matrix (11-17, 24) in which interlock operation is shown to be within the manufacturer's discretion.; The warning system, which is required to operate when the ignition i in the start position if the operations required by S7.4.1 to start the engine have not been performed, is on a different footing under conditions where the interlock is permitted, but not required, to operate. Under such conditions, S7.3.5.4 does not require the warning to operate in the start position. We would, however, strongly recommend that the warning system be designed to operate whenever the interlock prevents engine operation, regardless of whether or not S7.4.1 requires operation.; One other case in your table should also be corrected. Under Case 4 you indicate that interlock operation would be within the discretion of the manufacturer. It is our opinion that if the driver has properly operated his belt the interlock and warning system should not operate, even though the belt at the empty passenger's seat has been fastened.; Please advise us if you have further questions. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4093OpenMr. A. G. Beier, Chief Engineer, Brakes/Wheels, Navistar, P.O. Box 1109, Fort Wayne, IN 46801; Mr. A. G. Beier Chief Engineer Brakes/Wheels Navistar P.O. Box 1109 Fort Wayne IN 46801; Dear Mr. Beier: This responds to your letter concerning whether the Mini-Max brak system, produced by International Transquip Industries, Inc., complies with Federal Motor Vehicle Safety Standard (FMVSS) No. 121, *Air Brake Systems*. We apologize for the delay in our response. According to your letter, you have a number of concerns about the quality of the Mini-Max unit. You expressed concern about a letter from International Transquip which asserts that the Mini-Max brake system complies with FMVSS No. 121 and provides the names of Mr. James Brittel and Mr. Gerald Davis, both of the Bureau of Motor Carrier Safety (BMCS), for 'further confirmation.' You asked several questions which are answered below.; Your first question is whether a June 6, 1984 letter signed by Mr Gerald Davis of BMCS denotes approval of Mini-Max by either BMCS or NHTSA. Mr. Davis' letter indicates that BMCS reviewed material furnished by International Transquip concerning that company's parking brake system (i.e., the Mini-Max system) and states that the system 'appears to meet an interpretation issued by the National Highway Traffic Safety Administration in April 1974' an interpretation dated April 16, 1974, concerning FMVSS No. 121 .; As stated by Mr. Davis in his letter, the Federal Highwa Administration has a long-standing policy of not approving equipment. Likewise, NHTSA does not grant approvals of motor vehicles or motor vehicle equipment with respect to their compliance or noncompliance with Federal motor vehicle safety standards (FMVSS). The National Traffic and Motor Vehicle Safety Act, under which the standards are issued, provides that it is the manufacturers which have the responsibility for certifying the compliance of their products with the FMVSS.; Your second question is whether a 'certification of compliance provided by International Transquip has any significance. The document in question states that the Mini-Max brake system when installed per details provided by International Transquip meets or exceeds all Federal motor vehicle safety standards and Federal Highway Administration standards pertaining to air brake systems for trucks, buses and trailers as to fleet owners and operators. I will address your question to the extent of possible significance to compliance with FMVSS No. 121.; FMVSS No. 121 applies to trucks, buses, and trailers equipped with ai brake systems. See section S3, *Application*. The standard thus applies to vehicles and not directly to equipment. As an equipment manufacturer, International Transquip is not required to certify compliance of Mini-Max to Standard No. 121, but any vehicle manufacturer which would install Mini-Max would be required to make such certification. It is not uncommon for a vehicle manufacturer to request information from an equipment manufacturer as part of fulfilling its duty to exercise due care in certifying that a vehicle complies with applicable Federal motor vehicle safety standards. However, the responsibility for certification is on the vehicle manufacturer.; It is our opinion that reliance by a vehicle manufacturer solely on 'certification of compliance' provided by an equipment manufacturer, without more, would not be an exercise of due care. Moreover, should it be determined that a vehicle does not comply with a Federal motor vehicle safety standard or contains a defect, the recall and remedy obligations of sec. 151 *et seq.* of the National Traffic and Motor Vehicle Safety Act would fall upon the vehicle manufacturer and not the equipment manufacturer which supplied particular equipment. See 49 CFR Part 579. Possible liability in tort under state law could fall upon both the vehicle manufacturer and the equipment manufacturer.; Your third question is whether NHTSA has run any tests on the Mini-Ma unit and, if so, what the results were. NHTSA has not run any compliance tests on a Mini-Max unit but has run some tests for purposes of research and development. It is our understanding that Mr. Sid Williams of NHTSA's Office of Research and Development has already discussed these tests with you. It is also our understanding that International Transquip may have changed the design of the Mini-Max system since the tests were run.; We note that the California Highway Patrol (CHP) has raised a number o issues relating to the compliance and overall safety of Mini-Max brakes in connection with a petition for rulemaking, and that International Transquip has submitted comments on CHP's analysis. We have enclosed for your information a notice granting the CHP petition and three related interpretation letters, to International Transquip, the New Jersey Division of Motor Vehicles, and P.T. Brake Lining Company. The CHP and Mini- Max submissions have been placed in the Petitions for Rulemaking (PRM) Docket for FMVSS No. 121. If you desire copies of those submissions, please contact: Docket Section, National Highway Traffic Safety Administration, Room 5109, 400 Seventh Street, S.W., Washington, DC 20590 (202-426-2768).; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3756OpenMr. P. T. Miller, 90 W. 79th Avenue, Liberty Square, P.O. Box G, Merriville, IN 46410; Mr. P. T. Miller 90 W. 79th Avenue Liberty Square P.O. Box G Merriville IN 46410; Dear Mr. Miller: The Department of Commerce has forwarded your letter of September 27 1983, to Mr. Vinson of this office, for our reply. You have asked about Federal standards for motorcycle headlamps in connection with your investigation of an accident in Indiana involving a motorcycle reputedly equipped with 'a custom light approximately 2 1/2' by 5 '...smaller than a stock light.' Indiana Law requires that motorcycles be equipped with headlamps meeting Federal standards.; The principal Federal standard on motorcycle headlighting is SA Standard J584a, incorporated by reference in 49 CFR 571.108, Motor Vehicle Safety Standard No. 108. The standards do not list permissible sizes for motorcycle headlamps that are not sealed beam, specifying only that the light emitted comply with requirements at various photometric test points. Thus, the small size of the lamp in question is not indicative that it failed to meet Federal motorcycle requirements.; However, we are not aware that motorcycle headlamps are available i rectangular sizes smaller than those used on passenger cars, i.e., 4 inches by 6 inches. Perhaps the lamp in question was intended by its manufacturer for use as a driving lamp on passenger cars, its size is consistent with that type of lamp. But without further information I'm afraid we can be of no greater asistance (sic).; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4139OpenKarl-Heinz Faber, Vice President, Product Compliance and Service, Mercedes-Benz of North America, Inc., One Mercedes Drive, P.O. Box 350, Montvale, NJ 07645; Karl-Heinz Faber Vice President Product Compliance and Service Mercedes-Benz of North America Inc. One Mercedes Drive P.O. Box 350 Montvale NJ 07645; Dear Mr. Faber: This responds to your letter addressed to Mr. Barry Felrice concernin Federal Motor Vehicle Safety Standard No. 101, *Controls and Displays*, and use of the 'fanfare' symbol. According to your letter, all Mercedes-Benz passenger cars are provided with a horn that when activated produces an audible tone. The control for so activating the horn is located in the steering wheel hub. In addition to the standard horn, your company also offers an optional system on some models which permits the driver to choose either the standard tone or a higher frequency tone by means of a dash-board-mounted rocker switch. The rocker switch is identified by the fanfare symbol. The audible tone selected is then produced by activating the horn control in the steering wheel in the usual manner. This letter confirms that the use of the fanfare symbol for the rocker switch described above is permissible under Standard No. 101.; By way of background information, the National Highway Traffic Safet Administration does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles and equipment meet applicable safety standards. The following represents our opinion based on the facts provided in your letter.; Standard No. 101 requires that vehicles with any control listed in th standard must meet specified requirements for the location, identification and illumination of such control. See section S5. Among the controls listed in Standard No. 101 is the 'horn' control. See section S5.1 and column 1 of Table 1.; It is our opinion that the 'horn' control referred to by Standard No 101 is limited to that which activates the horn to produce an audible tone. Thus, a separate rocker switch which permits the driver to choose different tones but does not activate the horn to produce an audible tone is not considered to be a 'horn' control within the meaning of Standard No. 101. Since a control of this type is not otherwise covered by Standard No. 101 or any other standard, the identification of the control is at the option of the manufacturer.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3306OpenMr. J. Bill Simpson, Simpson Sports, 22630 South Normandie Avenue, Torrance, CA 90502; Mr. J. Bill Simpson Simpson Sports 22630 South Normandie Avenue Torrance CA 90502; Dear Mr. Simpson: This responds to your May, 1980, letter asking whether the Departmen of Transportation preempts State approval programs designed to enforce State standards on equipment regulated by Federal safety standards. In a subsequent conversation with Roger Tilton of my staff, you indicated that several States require you to obtain advance approval from them prior to sale of your motorcycle helmets. You further stated that each of these advance approvals can be very costly.; The National Traffic and Motor Vehicle Safety Act of 1966 (the Act) (1 U.S.C. 138 *et* *seq*.) in section 1392(d) preempts States from having any safety standard applicable to the same aspect of performance as a Federal standard unless the State standard imposes a higher level of performance and applies only to vehicles or equipment purchased for the State's own use. The Act is silent with respect to the preemption of State enforcement procedures, such as approval schemes that require State permission prior to the sale of vehicles or equipment in their jurisdictions.; We note that the issue of advance approval schemes was litigated i *Truck Safety Equipment Inst. v. Kane*, 466 F.Supp. 1242 (D.C., Pa. 1979). In that case (copy enclosed) the court held that a State advance approval scheme was preempted by the Act. We suggest that you bring this case to the attention of the appropriate officials in the States in question. If either you or officials from those States have further questions, you can contact Mr. Tilton at 202-426-9511.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5378OpenMr. J. L. Steffy Triumph Designs Ltd. Jacknell Road Dodwells Bridge Industrial Estate Hinckley, Leics. LE10 3BS England; Mr. J. L. Steffy Triumph Designs Ltd. Jacknell Road Dodwells Bridge Industrial Estate Hinckley Leics. LE10 3BS England; Dear Mr. Steffy: This responds to your FAX of May 5, 1994, to Taylo Vinson of this Office, requesting an interpretation of Motor Vehicle Safety Standard No. 108. You describe a motorcycle lamp 'which comprises a headlight with high and low beams and 2 symmetrically (sic) flanking front auxillary (sic) lamps possessing low beam (sic) that augment the headlight.' You ask for our comments. Paragraph S5.1.3 of Standard No. 108 permits auxiliary lighting equipment provided that it does not impair the effectiveness of the lighting equipment that is required by Standard No. 108. The vehicle manufacturer's certification of compliance with Standard No. 108 includes certification to S5.1.3 and represents its determination that the supplementary equipment does not impair the effectiveness of other lighting equipment. Unless that determination appears clearly erroneous, NHTSA will not question it. Your letter contains too little information for us to comment further. For example, we do not know whether the candela of the auxiliary lower beam lamps is higher, lower, or the same as the main lower beam of the headlamp. Nor does the letter indicate whether the supplementary lower beam lamps are extinguished when the upper beam is activated. If you have further questions, we shall be pleased to answer them. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam0480OpenMr. E. Theodore Gunaris, Chief Deputy Registrar, Registry of Motor Vehicles, The Commonwealth of Massachusetts, 100 Nashua Street, Boston, MA, 02114; Mr. E. Theodore Gunaris Chief Deputy Registrar Registry of Motor Vehicles The Commonwealth of Massachusetts 100 Nashua Street Boston MA 02114; Dear Mr. Gunaris: Thank you for your letter of September 17, 1971, asking if presen Federal regulations would preempt the Massachusetts requirement that certain outside rearview mirrors be provided with reflective material over the rear surface.; Section 103(d) of the National and Motor Vehicle Safety Act, 15 U.S.C 1392(d), states in pertinent part:; >>>'Whenever a Federal motor vehicle safety standard . . . is i effect, no State . . . shall have any authority . . . to establish . . . with respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard.'<<<; Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflectiv Devices, and Associated Equipment*, establishes requirements for reflective materials used on motor vehicles. The NHTSA considers this standard to include within its scope all reflective materials required to be used on motor vehicles to which it applies. Any State requirements that have the effect of regulating such reflective materials must therefore be identical to the relevant provisions of Standard No. 108. The Massachusetts statute that you have brought to our attention is not identical to the Federal standards relating to that aspect of performance, and must therefore be considered to be invalidated by the operation of the National Traffic and Motor Vehicle Safety Act.; Sincerely, Lawrence R. Schneider, 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.