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: aiam4480OpenMr. A. L. Bragg Laboratory Manager Truck-Lite Co., Inc. 310 East Elmwood Avenue Falconer, NY 14733; Mr. A. L. Bragg Laboratory Manager Truck-Lite Co. Inc. 310 East Elmwood Avenue Falconer NY 14733; Dear Mr. Bragg: This is in reply to your letter of June 22, l988, t Mr. Vinson of this Office asking for an interpretation of Motor Vehicle Safety Standard No. 108. It is your understanding that for purposes of measuring the effective projected illuminated area of a lens, the reflex area, if any, must be subtracted from the total lens area. Your company manufactures a combination lamp which 'has four square inches of reflector area and eight square inches of stop, tail and turn area.' You have asked if you may advise your customers that this lamp may be used on vehicles whose overall width is 80 inches or more: 'A) Singularly (that is one on each side of the vehicle in the rear) as a stop, turn, tail and reflex reflector? B) In combination of two's or three's (on each side of the rear of the vehicle), provided that the lamps are separated by at least twenty-two inches?' Your understanding is correct, that the effective projected illuminated lens area must be determined without reference to any reflex reflector that may be combined with it. If the turn signal function in your lamp is met by one compartment, your lamp is acceptable under 'A).' But if the turn signal function is met by more than one compartment, your lamp would not be acceptable as the area of each compartment is less than l2 square inches. With regard to 'B),' the lamps could be used in combinations of twos and threes if they are mounted more than 22 inches apart but could not be used if mounted closer than 22 inches. You also asked about the relationship to paragraph S4.1.1.7. This paragraph covers replacement equipment only, without reference to its location on a vehicle. It applies only to turn signal lamps intended to replace original equipment turn signal lamps on vehicles manufactured in accordance with SAE Standard J588d, June l966. The current original equipment requirement is SAE Standard J588e September l970. You should be aware that the Truck Safety Equipment Institute has petitioned for rulemaking the effect of which would be to extend the l2-inch requirement to lamps used on all wide vehicles without reference to the 22-inch spacing. At present the agency is reviewing this petition. I hope that this answers your questions. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1378OpenHonorable Charles H. Percy, United States Senate, Washington, DC 20015; Honorable Charles H. Percy United States Senate Washington DC 20015; Dear Senator Percy: This is in reply to your communication of January 3, 1974, forwardin to us correspondence dated November 29, 1973, from Mr. Bruce Motyka of Des Plaines. Mr. Motyka requests information regarding laws relating to pickup truck and camper weight limits, laws or studies relating to the sale of trucks exceeding GVW (Gross Vehicle Weight) rate minimums, and regulations or studies regarding maximum weights for tires.; The NHTSA has issued regulations relating to the installation o campers onto pickup trucks. Motor Vehicle Safety Standard No. 126 'Truck camper loading' (49 CFR S 571.126) requires each camper to bear a permanent label containing information on its maximum loaded weight. The standard also requires each camper to be furnished with an owner's manual that contains information on total camper weight, the selection of an appropriate pickup truck, appropriate methods of camper loading, how to determine the camper's center of gravity and where it should be placed in the truck cargo area. A companion 'Consumer Information' regulation, 'Truck camper loading' (49 CFR S 575.103) requires that written information be provided at the sale of each truck capable of being equipped with a slide-in camper that deals with the correct installation of a slide-in camper in that vehicle. This information is also required to be available in dealers' showrooms for retention by prospective purchasers of such trucks.; Other NHTSA regulations (49 CFR Part 567, 'Certification') requir every motor vehicle, including pickup trucks, to be labeled, usually on the driver's door or door jam, with its gross vehicle weight rating, and the gross axle weight rating for each axle. Each of these ratings is intended to be based on the weight of a fully loaded vehicle, as determined by the vehicle's manufacturer. While it is possible for manufacturers proposed course of action appears to have the aim of generating dissatisfaction with Federal tire regulations among dealers and distributors, and could, by lessening cooperation at the retail level, interfere with your client's ability to fulfill its obligations under the regulations.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam3345OpenMr. Bruce Henderson, Automobile Importers of America, Inc., 1735 Jefferson Davis Highway, Suite 1002, Arlington, Virginia 22202; Mr. Bruce Henderson Automobile Importers of America Inc. 1735 Jefferson Davis Highway Suite 1002 Arlington Virginia 22202; Dear Mr. Henderson: This responds to your September 4, 1980 letter to this office in whic you requested confirmation that a certain tire size was listed for use with a particular rim size in a tire publication recognized by this agency for purposes of Standard 110. Page 1-11 of the 1980 Yearbook of the Tire & Rim Association lists a 5 1/2 inch rim as appropriate for use with 185/70R14 tires. Thus, use of the 5 1/2 inch rims with that size tire would satisfy the requirements of paragraph S4.4.1(a) of Standard 110.; If you have any further questions or concerns regarding this matter feel free to contact Stephen Kratzke of my staff.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2942OpenMr. D. K. Haenchen, Administrator, Vehicle Regulations, Volkswagen of America, 27621 Parkview, Boulevard, Warren, MI 48092; Mr. D. K. Haenchen Administrator Vehicle Regulations Volkswagen of America 27621 Parkview Boulevard Warren MI 48092; Dear Mr. Haenchen: This is in reply to your letter of January 3, 1979, asking fo confirmation of your interpretation of Federal Motor Vehicle Safety Standard No. 108 as it applies to a braking system that Volkswagen proposes to use on its 1980 Dasher model.; Specifically, the Dasher will employ a single 'pressure switch on eac vehicle, meaning that the stop lamp will be activated by only one of the [two, split] service brake systems.' You asked whether this is consistent with S4.5.4 of Standard No. 108 which requires that 'the stop lamps on each vehicle shall be activated upon application of the service brakes.' You argued that it meets the standard because:; >>>'Neither FMVSS 571.105-75 nor 575.108 (sic) clearly specify th conditions under which the stop lights have to operate. Specifically, the regulations do not specify that the stop lamps must illuminate upon application of the service brake control if one of the circuits of a dual circuit hydraulic braking system failed.'<<<; We do not concur with your interpretation. S4.5.4 quite clearl specifies the conditions under which the stop lamps must operate--'upon application of the service brakes,' and it is immaterial which circuit of a dual circuit hydraulic braking system is braking the vehicle. Therefore, your proposed system would constitute an apparent noncompliance with Standard No. 108.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3650OpenMr. Robert B. Wessel, Consus International, Inc., P.O. Box 594, Port Jefferson Station, NY 11776; Mr. Robert B. Wessel Consus International Inc. P.O. Box 594 Port Jefferson Station NY 11776; Dear Mr. Wessel: This is in response to your December 1, 1982, letter regarding warning device you plan to manufacture. The device is powered by 4 AA batteries, and has a light which can stay on continuously or can flash. You have asked whether the device complies with Federal Motor Vehicle Safety Standard 125.; Standard 125 applies to warning devices 'without self- contained energ sources.' The four batteries in your device which power the light would constitute such a source. Therefore, Standard 125 is inapplicable to your device.; If you have further questions on this matter, feel free to contact us. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4195OpenMr. Andrew A. Kroll, 1401 East Girard, 207, Englewood, Colorado 80110; Mr. Andrew A. Kroll 1401 East Girard 207 Englewood Colorado 80110; Dear Mr. Kroll: This responds to your letter requesting an interpretation of Standar No. 109, *New Pneumatic Tires - Passenger Cars* (49 CFR S571.109). Specifically you asked whether that standard is applicable to foam-filled passenger car tires that do not have any air in the inner tire cavity. Standard No. 109 does not apply to foam-filled passenger car tires.; Section S2 of Standard No. 109 specifies that '[t]his standard applie to new pneumatic tire for use on passenger cars manufactured after 1948.' In section S3 of the standard, the term 'pneumatic tire' is defined as 'a mechnaical(sic) device made of rubber, chemicals, fabric and steel or other materials, which, when mounted on an automotive wheel, provides the traction and *contains the gas or fluid that sustains the load*' (emphasis added). Thus the relevant question is whether the foam filling the tires in question is considered a 'gas or fluid'. In a February 14, 1975 letter to Mr. J. F. Hutchinson, NHTSA stated that foam-filled tires 'should not be considered pneumatic tires.' This conclusion means that foam-filled tires for use on passenger cars are *not* subject to the requirements of Standard No. 109.; One result of this determination is that foam- filled tires can *not be installed as original equipment on any new passenger car. Standard No. 110, *Tire Selection and Rims* (49 CFR S571.110) sets forth requirements for new passenger cars. Section S4.1 of Standard No. 110 reads as follows: 'Passenger cars shall be equipped with tires that meet the requirements of S571.109.' Since foam-filled tires are not subject to Standard No. 109, they are still 'item of motor vehicle equipment' within the meaning of section 102(4) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1391(4)). Among other things, this means that, if there is a determination that the tires contain a defect related to motor vehicle safety, the manufacturer of the foam-filled tires is required to notify purchasers and dealers of the defect and remedy the defect without charge to the purchasers, if the tire was purchased less than 3 calender years before the determination of defect was made.; If you have any further questions on this subject or need mor information, please contact Steve Kratzke of my staff at this address or by telephone at (202) 426-2992.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1397OpenMr. J. Alec Reinhardt, Assistant Secretary and Attorney, White Motor Corporation, 100 Erieview Plaza, Cleveland, OH 44114; Mr. J. Alec Reinhardt Assistant Secretary and Attorney White Motor Corporation 100 Erieview Plaza Cleveland OH 44114; Dear Mr. Reinhardt: This is in response to your letter of February 4, regarding th proposed owner defect notification letter for defect notification campaign No. 73-0140.; Your letter fails to conform to 49 CFR, Part 577 as it states in th second sentence that the defect exists in equipment items manufactured and supplied by Rockwell International Corporation. We do not consider this statement to be responsive to 577.4(b)(1). As White Motor Corporation is the manufacturer of the motor vehicles involved, its determination and the statement required pursuant to 577.4(b)(1) must be to the effect that it has determined that a defect exists in the vehicles you identify in the following sentence.; The wording used by White Motor Corporation in the owner letter fo defect notification campaign No. 73-0242 is an example of a letter which does conform to the regulation.; The National Highway Traffic Safety Administration (NHTSA) is awar that there is a disagreement between White Motor Corporation and Rockwell International as to the exact cause of the defect. The NHTSA does not wish to become a party to this disagreement and in our opinion we cannot allow White Motor Corporation to use the owner notification letter as a forum to air their views.; I trust that you will make the appropriate changes to the owne notification letter and submit a revised copy to this office.; Sincerely, Andrew G. Detrick, Acting Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam3200OpenMr. J. Kawano, General Manager, U.S. Representative Office, Toyota Motor Co., Ltd., One Harmon Plaza, Secaucus, NJ 07094; Mr. J. Kawano General Manager U.S. Representative Office Toyota Motor Co. Ltd. One Harmon Plaza Secaucus NJ 07094; Dear Mr. Kawano: This responds to your recent letter asking whether a manual, Type 1 la belt assembly installed in conjunction with an upper torso automatic belt can qualify as the pelvic portion of a Type 2 belt assembly for purposes of the elongation requirements of Safety Standard No. 209, *Seat Belt Assemblies*.; Safety Standard No. 209 limits the elongation of webbing in a Type lap belt to 20 percent, but allows the webbing in the pelvic portion of a Type 2 belt assembly to elongate 30 percent. The standard defines a 'type 2 seat belt assembly' as a combination of pelvic and upper torso restraints. Although a manual lap belt installed in conjunction with an automatic upper torso belt is not in fact a 'combination' belt as originally contemplated by the definition, the function of the system is equivalent to the Type 2 belt. Therefore, since the pelvic portion of a Type 2 belt may elongate up to 30 percent under the requirements of the standard, we conclude that a lap belt installed in conjunction with an upper torso automatic belt should be considered the pelvic portion of a Type 2 system and subject to the same requirement.; To assure that all interested persons are aware of this interpretation the agency intends to amend Safety Standard No. 209 to clarify that manual lap belts installed in conjunction with automatic upper torso belts may meet the elongation requirements specified for Type 2 belts. The amendment will also specify that such lap belts must be labeled to indicate they are only intended for use with an automatic upper torso restraint. Rulemaking in this regard will be initiated in the near future.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4896OpenMr. Ken Hanna Lectric Limited, Inc. 7322 S. Archer Road Justice, Illinois 60458; Mr. Ken Hanna Lectric Limited Inc. 7322 S. Archer Road Justice Illinois 60458; Dear Mr. Hanna: This responds to your letter of July 8, 1991, t Richard Van Iderstine of this agency. You asked whether a proposed manufacturing and marketing scheme would be in violation of any NHTSA regulations. You intend to petition for rulemaking to amend Standard No. 108 to reinstate SAE Standard J579a as an optional standard for sealed beam headlamps. These lamps would be used on 'antique cars.' Until SAE J579a is reinstated, you would like to manufacture headlamps to conform to SAE J579c, the current specification for sealed beam headlamps that is incorporated into Standard No. 108. However, you do not wish to mark the lenses with the identification nomenclature that SAE J579c requires (presumably because it was lacking from the J579a headlamps with which the antique cars were originally equipped). You ask if you may market these lamps with identification on the package stating that they are 'for display purposes only and not approved for highway use.' Your letter clearly indicates that the purpose of manufacturing the sealed beam headlamps is for their installation on motor vehicles, albeit old ones, and not for 'display purposes only.' The headlamps are motor vehicle equipment, and must comply with all applicable Federal motor vehicle safety standards, in this instance, SAE J579c. Partial compliance with the requirements is not permissible, and the lenses of headlamps manufactured to conform with SAE J579c must be marked as that standard requires. Thus, your suggested manufacturing and marketing scheme would not conform to Standard No. 108, and, if pursued, it would be a violation of the National Traffic and Motor Vehicle Safety Act. The manufacture and sale of noncomplying motor vehicle equipment is a violation of the for which a civil penalty of up to $1,000 per violation may be imposed, up to a total of $800,000 for any related series of violations. In addition, as the manufacturer of the equipment, Lectric Limited must certify them as meeting all applicable Federal motor vehicle safety standards, and similar penalties may be imposed for certification that is false and misleading in a material respect. Finally, the manufacturer of nonconforming equipment is required to notify and remedy in accordance with the requirements of the Act. Because SAE J579a and 579c headlamps are identical in external appearance except for lens marking, we do not believe that authenticity of the appearance of older vehicles will be affected to any discernable degree by requiring that their lenses be marked as the contemporary standard requires. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam2041OpenMr. James H. Whitaker, Associate Professor, The University of Connecticut, Storrs, CT 06268; Mr. James H. Whitaker Associate Professor The University of Connecticut Storrs CT 06268; Dear Mr. Whitaker: Please forgive the delay in responding to your letter of May 22, 1975 which inquired about the status of tire grading standards.; On May 20, 1975, the National Highway Traffic Safety Administratio issued the Uniform Tire Quality Grading Standards with a series of effective dates beginning January 1, 1976 (40 FR 23073, May 28, 1975). On July 3, 1975, the regulation was republished with minor changes (40 FR 28071). On August 14, 1975, a stay of the effective dates was granted by the United States Court of Appeals for the Sixth Circuit, pending review of the validity of the regulation in a suit brought by eight tire manufacturers.; For your convenience, I have enclosed copies of the Federal Registe notices referred to above.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.