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: aiam2194OpenKenneth R. Arnold, Esq., Secretary and General Counsel, WAGNER ELECTRIC CORPORATION, 100 Misty Lane, Parsippany, NJ, 07054; Kenneth R. Arnold Esq. Secretary and General Counsel WAGNER ELECTRIC CORPORATION 100 Misty Lane Parsippany NJ 07054; Dear Mr. Arnold: This is in reply to your letter of December 11, 1975, referring to ou letter to Ideal Corporation of September 17, 1975. You commented that 'customers believe that the NHTSA approves the unqualified use of variable-load flashers for replacement turn-signal applications.' You have requested 'confirmation that the intent of Standard 108, S4.5.6 is to only permit a variable-load flasher to be used only on an Excepted Vehicle.' Your interpretation is incorrect.; Although the NHTSA does not approve of the use of variable-load tur signal flashers as replacement for fixed-load flashers, the choice of replacement equipment for a vehicle in use is that of the consumer, and is not subject to Federal control. We have no authority to require that the owner of a vehicle originally equipped with a fixed load flasher replace it with a fixed load flasher. This may be the reason for your confusion with respect to the NHTSA's reaction to Ideal Corporation's petition for rulemaking. It was not necessary to amend the standard as requested by Ideal, since it already allowed the type of replacement suggested, and this agency generally does not regulate modifications by consumers. Such an amendment would have been superfluous.; As indicated in our letter to Ideal, we continue to believe i preferable that consumers be informed that a variable load flasher will not provide an outage indication. To this end the NHTSA is considering rulemaking that would require labeling on containers of variable-load flashers.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4943OpenMr. Terry Semprini Executive Director Cycle Country Accessories Corp. Rt. 3, Box 125 Hwy 71 North Milford, Iowa 51351; Mr. Terry Semprini Executive Director Cycle Country Accessories Corp. Rt. 3 Box 125 Hwy 71 North Milford Iowa 51351; Dear Mr. Semprini: This responds to your letter of December 10, 1991 to Taylor Vinson of this Office, asking whether a lighting device developed by your company 'is legal to run in all of the United States.' From the pictures you enclosed, we note that your device is a diamond-shape lamp, incorporating six amber lamps which form right and left turn signals. In addition, four red lamps are used for stop and hazard warning lamp purposes. These lamps are arranged in a V shape at the top of the device, and an inverted V at the bottom. In the photos you enclosed, the device appears installed near the top of the truck, to the left of the vertical centerline, midway between the centerline and the left edge of the vehicle. It appears that the intent of this device is, in the position depicted, to serve as the vehicle's turn signal lamps, hazard warning signal lamps, and stop lamps in the event that the original equipment lamps were obscured by one or more intervening vehicles. This would occur were the stop lamps and turn signal lamps mounted at the bottom of the vehicle body, as depicted in your photographs. By way of background information, Section 103 of the National Traffic and Motor Vehicle Safety Act (Safety Act, 15 U.S.C. 1392) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal motor vehicle safety standards for new motor vehicles and new items of motor vehicle equipment. We have exercised this authority to establish Standard No. 108, Lamps, Reflective Devices, and Associated Equipment (49 CFR ?571.108). Standard No. 108 applies to new motor vehicles and to lamps, reflective devices, and associated equipment for replacement of original equipment lamps, reflective devices, and associated equipment. As noted above, it appears that your company's lighting device would be offered as an aftermarket item to supplement, not replace, the original equipment lamps. Assuming this is the case, Standard No. 108 would not directly apply to your company's lighting device and your company would not be required to certify that the lighting device conforms with Standard No. 108. Even though Standard No. 108 does not appear to directly apply to this lighting device, there is a provision of the Safety Act that applies to the installation of aftermarket items of motor vehicle equipment. Section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)) prohibits any manufacturer, distributor, dealer, or repair shop from knowingly 'rendering inoperative,' in whole or in part, any device or element of design installed on or in a vehicle in compliance with an applicable safety standard. The effect of this provision is to make it unlawful for any of the named commercial establishments to add or replace any lamp, reflective device, or associated equipment on a motor vehicle if the commercial establishment knows or should know that the addition of the aftermarket lighting equipment results in the vehicle no longer complying with Standard No. 108. It appears that your company's lighting device would 'render inoperative' the required lighting equipment on a trailer by impairing its effectiveness. First, we note that the device as positioned fails to fulfill basic locational requirements of Standard No. 108 that rear lamps be installed one on each side of the vertical centerline and as far apart as practicable. The signal sent by these lamps could therefore be perceived as conflicting or unclear when viewed simultaneously with the original equipment lamps. Second, we note that the hazard warning system of the device operates through the stop lamps rather than through the turn signal system as is the case with original equipment. This means that a viewer could be faced with the necessity of interpreting the meaning of simultaneously flashing red and amber lamps on the rear of the vehicle, as well as the meaning of the original stop lamps should the brakes also be applied. Finally, we note that the stop lamp portion of the device, two lamps forming a V and two more an inverted V, form a lighting array that the public does not associate as a traditional stop lamp system, usually circular or rectangular lamps. Thus, a viewer to the rear could be faced with a momentary delay in interpreting the meaning of the simultaneous appearance of light from the stop lamps, and from the auxiliary device mounted to the left of center on the rear of the vehicle. For the above reasons, we view your device as having the potential to render inoperative certain rear lamps required on trailers by Standard No. 108. Accordingly, it would be a violation of Federal law for any manufacturer, distributor, dealer, or repair shop to install your company's lighting device on a customer's trailer. This 'render inoperative' prohibition does not apply to individual vehicle owners. Vehicle owners may add lighting devices or make other modifications to their own vehicles without violating any provision of Federal law, even if the owner's modifications result in the vehicle no longer complying with Standard No. 108. However, the individual States are free to establish whatever restrictions, if any, they deem appropriate on individual owner modifications. Thus, a State or States might choose to prohibit individual owners from equipping their trailers with your company's lighting device. We are unable to advise you on the laws of the individual States. You can obtain further information on State laws by writing to: American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam0453OpenMr. David A. Phelps, Jr., Group Supervisor, Engineering Services, Blue Bird Body Company, Fort Valley, GA 31030; Mr. David A. Phelps Jr. Group Supervisor Engineering Services Blue Bird Body Company Fort Valley GA 31030; Dear Mr. Phelps: In your letter of October 4, 1971, you asked whether under ou Certification regulations (49 CFR Part 567) tandem axles should be considered as a unit in listing the gross axle weight rating, or should be listed separately with separate ratings.; We intend that each axle, including those part of a tandem arrangement should be listed separately with a GAWR for each.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam2340OpenHonorable Mark O. Hatfield, United States Senate, Washington, D.C. 20510; Honorable Mark O. Hatfield United States Senate Washington D.C. 20510; Dear Senator Hatfield: This is in response to your March 10, 1976, letter concerning th application of Federal Motor Vehicle Safety Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other than Passenger Cars*, to the paver manufactured by Layton Manufacturing Company. The standard requires that the paver be equipped with ties of sufficient load rating and that these tires be certified by their manufacturer as complying with Standard No. 119, *New Pneumatic Tires for Vehicles Other than Passenger Cars*. Your constituent, Mr. Earl Sievers, has met with representatives of this agency to discuss the need for his company's paver to comply with Standard No. 120 and his difficulties in procuring the proper tires.; Your letter suggests that, generally, the paver is moved simply withi the confines of a construction site rather than in traffic. Nevertheless, the paver is designed and expected to be towed on the public highways. Indeed, Layton's own promotional materials stress this point:; >>>For municipalities who do not own their dump trucks or need extrem mobility without sacrificing hauling weight! ... Any truck can tow paver safely at highway speeds. ('exhibit 'C'' accompanying Mr. Sievers' letter of January 14, 1976.)<<<; This usage of the paver leads to the conclusion that the paver is 'motor vehicle' subject to all applicable Federal motor vehicle safety standards, including Standard No. 120. The conclusion is compelled by the definition of 'motor vehicle' in the National Traffic and Motor Vehicle Safety Act of 1966, as amended (15 U.S.C. 1391 et seq.). As a manufacturer of fewer than 10,000 motor vehicles in its most recent year of production, Layton is eligible to petition for a temporary exemption from Standard No. 120 on the basis of substantial economic hardship. For your convenience, I am enclosing a copy of 49 CFR Part 555, *Temporary Exemption from Motor Vehicle Safety Standards*, which sets out procedures for filling and processing such petitions.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam5485OpenMr. Gary Shultz Vice President, General Counsel and General Manager--Public Relations Diamond Star Motors 100 North Diamond Star Parkway Normal, Illinois 61791; Mr. Gary Shultz Vice President General Counsel and General Manager--Public Relations Diamond Star Motors 100 North Diamond Star Parkway Normal Illinois 61791; "Dear Mr. Shultz: This responds to your letter asking about Part 583 Automobile Parts Content Labeling. You noted that section 583.6 specifies that manufacturers are to determine the percentage U.S./Canadian Parts Content for each carline on a model year basis, before the beginning of each model year. You stated, however, that the regulation does not indicate what should be done when there is a change of plans in the source of production for a particular carline in the middle of the model year. According to your letter, one of your carlines currently in production will now be manufactured in both the U.S. and Japan, which may significantly affect the carline's current calculation for content as well as the final assembly point. You requested confirmation whether the label should be changed to reflect the change in domestic/foreign content in the middle of the model year or whether section 583.6 should be relied on as the authority for determining a carline's content only on a one-time model year basis. You also requested confirmation as to whether the label should be changed to reflect the final assembly point in accordance with section 583.5(e). Your questions are addressed below. By way of background information, section 583.5(a) requires manufacturers to provide five basic items of information on the label: (1) U.S./Canadian parts content, (2) Major sources of foreign parts content, (3) Final assembly point, (4) Country of origin for the engine, and (5) Country of origin for the transmission. The first two items are determined on a 'carline' basis, the last three items are determined with respect to individual vehicles. Both Part 583 and the American Automobile Labeling Act (now codified at 49 U.S.C. 32304) contemplate that U.S./Canadian parts content and Major sources of foreign parts content are determined on a once-a-model-year basis for a particular carline. In particular, section 32304(b)(2) reads as follows: At the beginning of each model year, each manufacturer shall establish the percentages required for each carline to be indicated on the label . . . . Those percentages are applicable to that carline for the entire model year. . . . We believe that Congress included this provision to reduce unnecessary manufacturer costs, and was seeking to make it clear that the manufacturers could not be required to revise their calculations during the model year. The specified percentages are estimates by nature, and the assumptions underlying them are subject to change during the model year. It would be very burdensome to manufacturers to be required to constantly recalculate the estimated percentages throughout the model year. Your letter raises the issue, however, of whether a manufacturer is permitted to revise the carline percentages in the event of a major change in source of production during a model year. It is our opinion that a manufacturer may revise the percentages in such circumstances, at its option. Such revision would be analogous to correcting an error and would prevent the possibility of misleading consumers. If you do make such a revision, however, the revised estimates should reflect the model year as a whole and not just the balance of the model year. In addition, the label should include a note indicating that the carline percentages have been revised during the model year. This is necessary to prevent confusion when consumers compare the labels of vehicles within the same carline manufactured at different times. You also asked whether the label should be changed to reflect the final assembly point in accordance with section 583.5(e). Since final assembly point is determined for individual vehicles rather than carlines, the label must be changed to indicate the actual final assembly point of the vehicle. See section 583.5(a)(3). The section which you cited, i.e., section 583.5(e), permits manufacturers to provide additional information for carlines assembled in the U.S./Canada and in one or more other countries. Since your carline would now be assembled in the U.S./Canada and Japan, your company may avail itself of this option. I note that section 583.5(e)(3) provides that a manufacturer selecting this option for a particular carline must provide the specified additional information on the labels of all vehicles within the carline. In your situation, you would need to provide the additional information on the labels of all vehicles within the carline, beginning from the time the vehicles were manufactured in both places. I hope this information is helpful. Sincerely, Philip R. Recht Chief Counsel"; |
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ID: aiam1995OpenMr. James E. Johnson, Chief Engineer, Construction Machinery Company, P.O. Box 120, Waterloo, IA 50704; Mr. James E. Johnson Chief Engineer Construction Machinery Company P.O. Box 120 Waterloo IA 50704; Dear Mr Johnson: This responds to your June 18, 1975, question whether a system whic pressurizes a water tank on a concrete mixer by means of air from the truck's air brake system would violate the requirements of Standard No. 121, *Air brake systems*.; The answer to your question is no. Standard No. 121 does not contain prohibition on the use of air pressure from the air brake system for powering auxiliary devices. The vehicle must of course conform to Standard No. 121 following installation of the device if the installation occurs prior to the first purchase in good faith for purposes other than resale.; Although not a requirement of the standard, the National Highwa Traffic Safety Administration does consider it appropriate that a pressure protection valve be placed in the line to the auxiliary device so that a rupture of an auxiliary line does not cause depletion of air pressure in the brake system.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0687OpenMr. Frank J. Fefferman, Vice President, Sales and Product Development, Stylar Industries Inc., 2979 Ontario Street, Burbank, CA 91503; Mr. Frank J. Fefferman Vice President Sales and Product Development Stylar Industries Inc. 2979 Ontario Street Burbank CA 91503; Dear Mr. Fefferman: This is in reply to your letter of March 22, 1972, on the subject o the application of Motor Vehicle Safety Standard No. 207 to the type of swivelling seat manufactured by your company.; We understand from your letter that you are concerned about the type o swivelling seat that is not continuously fastened to its base and that can therefore come loose in a rollover accident. To avoid this problem, you have designed your seat with a stud bolt that links the seat to its base regardless of the amount of rotation. Your question to us is whether removal of the stud bolt would cause the seat not to conform to Standard 207.; The answer to your question depends in part on whether the seat withou the bolt would be able to meet the applicable strength requirements of the standard. Removal of the stud bolt would not, in itself, cause the seat not to conform to the standard. The seat would conform to S4.3 if the seat were to lock itself by means other than the bolt when returned to the forward facing position.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3802OpenMr. Barry M. Davis, Vice President, Proto-Systems, Inc., P.O. Box 871, Pembroke, Massachusetts 02359; Mr. Barry M. Davis Vice President Proto-Systems Inc. P.O. Box 871 Pembroke Massachusetts 02359; Dear Mr. Davis: This is in reply to your letter of December 29, 1983, with respect t the 'Headlight Kit' which you manufacture as ' an aftermarket add-on headlamp concealment device for the Camaro.' You have stated that it will be sold in retail outlets and be offered by Chevrolet dealers as a new car option. You have asked whether the product requires certification under Safety Standard No. 112 and, if so how may it be included in your packaging and promotional material. If you are not required to certify, you would like to know if you may use the DOT symbol and the phrase 'meets Federal safety standards' on your packaging.; We have two types of safety standards: those that vehicles must meet and those that individual equipment items must meet. Safety Standard No. 112, *Headlamp Concealment Devices*, is an example of the former, when equipped with a headlamp concealment device, a vehicle must meet certain performance requirements. The vehicle must meet these requirements at the time of sale to the first purchaser for purposes other than resale, and be certified as meeting the requirements. Certification of compliance with the vehicle safety standards is provided by the vehicle manufacturer, however, if the vehicle is altered before its sale, in more than a minor way, the alterer must provide an additional certification identifying himself as a modifier and that the vehicle as modified continues to meet the standards. Assuming that Chevrolet dealers perform the modification, it is they, not you who must apply the alterer's label. The alterer's certification requirements are contained in 49 CFR Section 567.7.; Once a vehicle has been sold, no alterer's certification is required but the party performing the alterations is required to insure that he is not rendering inoperative in whole or in part' the headlight system. We would interpret this to mean that if the concealment system's performance were not the equivalent of that obtainable under Standard No. 112 a violation might exist. This prohibition is established by Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act. However, the prohibition does not preclude the vehicle owner from himself making any modification he chooses (subject, of course, to local law).; This means that regardless of whether your system is sold to new ca dealers or to retail stores in the aftermarket your company has no certification responsibility. Thus, the use of a DOT symbol would be improper and could even be viewed a technically false and misleading under Section 108(a)(1)(C) of the Act, for which a civil penalty might be imposed. The phrase 'meets Federal safety standards' is also inaccurate. However, if your tests and other data clearly indicate that a Camaro would meet Standard No. 112 with the system in place, we would not object to your including a qualifying phrase such as 'Vehicle can meet Federal Motor Vehicle Safety Standard No. 112 if system is installed in accordance with instructions.' That would afford a basis upon which the new car dealer could rely in affixing his alterer's label, and would reassure an after-sale modifier that he was not violating the Act.; I hope that this has been helpful to you. For your information, enclose copies of Standard No. 112, 49 CFR Part 567, *Certification*, and the Act.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2710OpenMs. Jill M. Zick, Burley, Smiertka, Swank, and Misko, P.C., 2525 W. Jefferson, Trenton, MI 48183; Ms. Jill M. Zick Burley Smiertka Swank and Misko P.C. 2525 W. Jefferson Trenton MI 48183; Dear Ms. Zick: This responds to your September 6, 1977, letter asking whether th requirements of the National Highway Traffic Safety Administration (NHTSA) apply to your client, an alterer of motor vehicles. From the description in your letter, it appears that your client intends to alter previously certified vehicles to make them accessible to the handicapped. You ask what, if any, regulations would apply to this alteration.; There are no safety standards applicable to the installation of th devices to which you refer. Your client's responsibility for purposes of compliance with the regulations of the NHTSA would be to ensure that he does not affect the compliance of previously certified vehicles.; If your client modifies certified vehicles prior to their firs purchase for purposes other than resale, he would be responsible for ensuring that they continue to comply with all applicable motor vehicle safety standards. The applicable regulation, Part 567, *Certification*, (49 CFR Part 567.7), requires that he attach an alterer's label to each vehicle indicating that the vehicle continues to comply with the safety standards.; If your client modifies vehicles after their first purchase fo purposes other than resale, he would not have to attach an alterer's label to them. However, he would not be allowed to render inoperative any device or element of design installed in the vehicle in compliance with a motor vehicle safety standard (Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1397). Thus, whatever manufacturing operation was performed by your client, it would be necessary for him to ensure that all aspects of the vehicle covered by motor vehicle safety standards remain in compliance with those standards.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4294OpenMr. T. Chikada, Manager, Automotive Lighting, Engineering Control Dept., Stanley Electric Co., Ltd., 2-9-13, Nakemeguro, Meguro-ku, Tokyo 153, Japan; Mr. T. Chikada Manager Automotive Lighting Engineering Control Dept. Stanley Electric Co. Ltd. 2-9-13 Nakemeguro Meguro-ku Tokyo 153 Japan; Dear Mr. Chikada: This is in reply to your letter of March 13, 1987, with respect to th mounting height of driving lamps and front fog lamps. Noting that these Lamps are not equipment required by Federal Motor Vehicle Safety Standard No. 108, you have asked whether they need to be mounted within the range of height which the standard prescribes for headlamps, or may they be mounted, for example, at a height lower than 22 inches such as in the front bumper.; Any lamp that is not required by Standard No. 108 may be added to motor vehicle and located wherever it appears suitable, provided that the lamp at its location does not impair the effectiveness of lighting equipment required by the standard. Headlamps, parking lamps, and turn signal lamps are the lighting equipment required by Standard No. 108 on the front of a passenger car, and any other four-wheeled vehicle of less than 80 inches overall width. Although Standard No. 108 impose a minimum mounting height of 22 inches on headlamps, it allows parking lamps and turn signal lamps to be mount as low as 15 inches above the road surface which means that they could be mounted in the front bumper, or otherwise close to the mounting location of fog lamps and driving lamps. Therefore, compliance with paragraph S4.1..3 of Standard No. 108 would require a manufacturer of a vehicle equipped with fog and driving lamps to ensure that they do not impair the effectiveness of the headlamps, turn signal lamps, and parking lamps.; Because fog lamps and driving lamps are not covered by Standard No 108, the individual States may have their own restrictions on the mounting height of these lamps. We regret that we are unable to advise you on these laws. However, the American Association of Motor Vehicle Administrators (AAMVA), 1201 Connecticut Ave., N.W., Washington, D.C., may be able to advise you.; Sincerely, Erika Z. Jones, 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.