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: aiam2776OpenMr. R. M. Premo, Vehicle Planning and Development Center, Sheller-Globe Corporation, 3555 St. Johns Road, Lima, OH 45804; Mr. R. M. Premo Vehicle Planning and Development Center Sheller-Globe Corporation 3555 St. Johns Road Lima OH 45804; Dear Mr. Premo: This confirms the discussion held among you, Mr. Roger Tilton, Mr. Gu Hunter, and Mr. Martin Paliokas on February 14, 1978, concerning the applicability of Standard No. 221, *School Bus Body Joint Strength*, and Standard No. 113, *Hood Latch Systems*, to your vehicles.; In your first question, you asked whether the joint connecting a piec of metal that is attached to a body pillar and which is covered by the exterior body panels is a joint regulated by Standard No. 221. The standard regulates a 'body panel joint' which is defined as 'the area of contact or close proximity between the edges of a body panel and another body component,....' 'Body panel' is defined as 'a body component...used to enclose the bus' occupant space.' The piece of metal to which you refer becomes a part of the pillar and serves no purpose in enclosing occupant space. Therefore, the joint connecting these two body members is not a body panel joint and is not subject to the standard.; In your second question, you ask whether a hood latch system ca utilize two pin-type latches, one on each side of the hood, to comply with Standard No. 113. The standard specifically permits the use of two hood latch systems. The use of these two distinct pins would appear to comply with the requirements.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5637Open"Mr. B rje Kukka Humalistonkatu 5 00250 Helsinki FINLAND"; "Mr. B rje Kukka Humalistonkatu 5 00250 Helsinki FINLAND"; "Dear Mr. Kukka: This responds to your request for an interpretatio whether NHTSA's statutes and regulations would apply to a process you intend to market, in which two horizontal parallel grooves are etched into the lower portion of motor vehicle windshields. The groves apparently facilitate windshield cleaning by scraping water and debris off the windshield wipers as the wipers pass over the grooves. You provided a videotape on the process and a portion of a windshield etched with the grooves. I am enclosing two interpretation letters, one dated March 1, 1985 and another dated October 28, 1988, both addressed to Mr. Andrew P. Kallman of Lansing, Michigan. Mr. Kallman asked NHTSA's opinion of a process that is very similar to your process. The letters explain how NHTSA's regulations would apply if your process were used on new vehicles or windshields and on windshields of a used vehicle. Please also note, NHTSA has no authority to 'approve' or certify your process. If you understood any previous correspondence from agency personnnel to mean that NHTSA approves of your product, has endorsed it in any manner, or has made commendations about it (e.g., it 'can improve a driver's ability to drive safely'), that is incorrect, and we apologize for any confusion. State laws may affect operations that you conduct in that State. If you decide to do business in a particular State, you should seek legal advice on requirements for conducting your type of business in that State, including requirements the State may have for persons modifying windshields or for vehicles with modified windshields. I hope the enclosed information is helpful to you. Should you have any questions concerning NHTSA's legal authority, please write to me at this address or contact Dorothy Nakama of my staff at (202) 366-2992. Our FAX number is (202) 366-3820. I am, under separate cover, returning your videotape and windshield portion. Sincerely, Samuel J. Dubbin Chief Counsel Enclosures"; |
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ID: aiam5571OpenK. Howard Sharpe, Esq. Aranson Law Office P.O. Box 5296 Grand Forks, ND 52806-5296; K. Howard Sharpe Esq. Aranson Law Office P.O. Box 5296 Grand Forks ND 52806-5296; Dear Mr. Sharpe: This responds to your further letter of June 13, 1995 with reference to your client, NYTAF Industries, Inc. You have informed us that NYTAF will sell in the aftermarket its rear lighting system that displays verbal messages. You ask whether NYTAF must certify compliance with the Federal motor vehicle safety standards as 'it is simply a manufacturer of an accessory.' The answer is no. The only aftermarket lighting equipment for which certification of compliance is required is equipment that is manufactured to replace any item of required original lighting equipment on a vehicle. The NYTAF system is not intended to replace any item of original equipment, and no certification is required. However, because the NYTAF system is 'manufactured or sold . . . as an accessory or addition to a motor vehicle', it is 'motor vehicle equipment' as defined by 49 U.S.C. 30102(a)(7)(B). This means that if either NYTAF or NHTSA determines that there is a safety related defect in the system, NYTAF will be required to notify and remedy according to statutory provisions. If you have any further questions you may refer them to Taylor Vinson of this Office (202-366-5263). Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam1956OpenMr. Samuel W. Alderson, President, Humanoid Systems, Division of Alderson Biotechnology Corporation, 5250 El Segundo Boulevard, Hawthorne, CA 90250; Mr. Samuel W. Alderson President Humanoid Systems Division of Alderson Biotechnology Corporation 5250 El Segundo Boulevard Hawthorne CA 90250; Dear Mr. Alderson: This is in response to your letter of May 30, 1975, to th Administrator.; Thank you for the offer to assist in the establishment of ne specifications for dummy skin and flesh components. Any procurement of such services would be awarded by competitive procurement, and I hope your company will participate in any such competition when solicited.; The NHTSA issued Part 572, in the form of a large number of dumm design and material specifications supplemented by some calibrating component tests, in order to specify the vehicle performance requirements of certain crash-test standards, such as Standard No. 203, as precisely and objectively as possible. Dummies are not regulated items and not ends in themselves, as S 572.3 states, the dummy specification 'does not in itself impose duties or liabilities on any person.' Thus, the dummy specification serves only as a means of informing the vehicle manufacturers how their vehicles must perform if and when tested by the government. There is no regulatory requirement either for 'certification' of dummies or their 'verification by an independent agency' or anyone else. It may be assumed that government testing will be carried out with dummies that conform to Part 572 as closely as possible. Vehicle manufacturers can ascertain that their vehicles will pass government tests by any means they choose. With this in view, it should be clear that any deviations from the Part 572 specifications are purely a matter of private negotiation and decisionmaking between the dummy manufacturers and their customers, and no governmental 'approvals' are possible or appropriate.; Any changes in Part 572 will of course be done through notice an opportunity for comment, and we expect and hope for your full participation in an administrative proceeding when it takes place.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam1719OpenMr. Helmuth von Beckman, Technical Director, Tamper, Inc., 2401 Edmund Road, West Columbia, SC 29169; Mr. Helmuth von Beckman Technical Director Tamper Inc. 2401 Edmund Road West Columbia SC 29169; Dear Mr. von Beckman: This responds to your November 22, 1974, request for a determination o whether Tamper Corporation's products qualify as motor vehicles subject to Standard No. 121, *Air brake systems*. All of the vehicles you describe are designed only for use on a rail or rails, except for the Kal-Trac switcher, which has both steel wheels for rail use and pneumatic tires for highway use.; I have enclosed a discussion of our regulatory authority over moto vehicles which explains that all of your products which operate exclusively on a rail or rails are not subject to our regulations.; In a December 9, 1974, telephone call with Mr. Herlihy of this office you stated that the Kal- Trac switcher has axles with a gross axle weight rating (GAWR) in excess of 29,000 pounds. I enclose a copy of an NHTSA proposal that would exempt such a vehicle from Standard No. 121. We will consider your letter as support for this proposal.; Please contact Mr. Herlihy by phone (202-426-9511) after January 15 1975, to be advised if this proposal has been made final as an exemption for your vehicles from the standard.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3778OpenCapt. Bill Perzinsky, President, TWI Inc., 14525 Bessemer Street, Van Nuys, CA 91411; Capt. Bill Perzinsky President TWI Inc. 14525 Bessemer Street Van Nuys CA 91411; Dear Capt. Perzinsky: This is in reply to your letter of October 14, 1983, to Mr. Vinson o my staff regarding your F-S- 700 A flasher. The device is essentially a slender bar of lights mounted on the rear panel shelf of a passenger car. The left and right sides blink to indicate turns in the appropriate direction. The entire bar lights up when the brake pedal is applied. You ask for our 'approval' of this device.; The Federal motor vehicle safety standard on lighting forbids th installation of motor vehicle equipment that impairs the effectiveness of lighting equipment required by the standard. Stop lamps are required by the standard. They must be red. They must go on when the brake pedal is applied. The stop signal put out by the F-S-700 flasher is amber, not red. Therefore, an amber signal coming on at the same time as a red one would impair the effectiveness of the red stop lamp by creating confusion.; The Federal lighting standard allows either amber or red turn signa lamps. There is obviously a potential for confusion if your amber light device is on a vehicle whose turn signals are red. But an even greater problem with interior-mounted lamps, whatever their color, is the reflection that they cause in the rear glass, particularly when it's raining or snowing, interfering with the rear vision of the vehicle's driver.; For the reasons given above the F-S-700 A flasher causes us som concern. Further, you should investigate whether the laws of the jurisdiction where you wish to sell this device will permit its installation and use.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0158OpenMr. Richard R. Miller, President, Amerada Glass Company, 2001 Greenleaf Avenue, Elk Grove Village, IL 60007; Mr. Richard R. Miller President Amerada Glass Company 2001 Greenleaf Avenue Elk Grove Village IL 60007; Dear Mr. Miller: This is in reply to your letter of April 22, 1969, forwarded to me b the Federal Trade Commission.; A windshield classified as a second by the manufacturer mus nevertheless meet the requirements of Motor Vehicle Safety Standard No. 205 (Glazing materials).; If you have any information indicating that windshields marked second do not comply with the standard I would appreciate your sending me such information with the names of the manufacturers and dealers selling the windshields so that the Bureau can further investigate the matter.; Sincerely, Robert Brenner, Acting Director |
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ID: aiam2517OpenMr. Richard Hadley, Chief Product Engineer, Harman International Industries, Inc., P.O. Box 329, Bolivar, Tennessee 38008; Mr. Richard Hadley Chief Product Engineer Harman International Industries Inc. P.O. Box 329 Bolivar Tennessee 38008; Dear Mr. Hadley: This responds to your February 2, 1977, request for approval of Harma Industries procedure for measuring the average reflectance value of its 'Nite-Ban' rearview mirror. You describe the 'Nite-Ban' as a mirror glass having a band of low reflectance horizontal to the horizon and centered between the top and bottom of the glass. You request confirmation that the 'Nite-Ban' mirror conforms to the requirements of Standard No. 111, *Rearview Mirrors*.; Paragraph S11 of Standard No. 111, 49 CFR 571.111, specifies that th *average* reflectance value of any mirror required by the standard shall be at least 35 percent, determined in accordance with SAE Recommended Practice J964a. If the average reflectance value of the reflective surface of a 'Nite-Ban' mirror is at least 35 percent, the mirror is acceptable under Standard No. 111. However, it is the responsibility of the manufacturer to determine if an item of motor vehicle equipment complies with applicable safety standards. The agency cannot grant prior approval.; Further, the agency cannot approve a manufacturer's test procedures i advance. Therefore, we cannot confirm that your proposed procedure for measuring the average reflectance value of 'Nite-Ban' mirrors is an acceptable procedure. It is the manufacturer's responsibility to exercise sound engineering judgement in determining that its vehicle meet the performance levels prescribed in the safety standards.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam3731OpenMr. Dale Scott, R.V. Account Executive, Kinder Division, Congoleum Corporation, 2323 South 17th Street, P.O. Box 1207, Elkhart, IN 46515; Mr. Dale Scott R.V. Account Executive Kinder Division Congoleum Corporation 2323 South 17th Street P.O. Box 1207 Elkhart IN 46515; Dear Mr. Scott: This responds to your letter to Mr. Kratzke of my staff, asking for a interpretation concerning Safety Standard No. 302, *Flammability of Interior Materials* (49 CFR S571.302). Specifically, you asked whether innerspring mattresses used in motor homes are subject to the requirements of that standard. You also asked for a definition of the term 'mattress cover.'; Section S4.1 of Standard No. 302 lists the components that are covere by the standard. That list states that mattress covers must comply with the standard's requirements, but not the innerspring mattress itself. Hence, the innerspring mattress with which you are concerned is not subject to the flammability requirements of Standard No. 302. As your letter noted, those mattress (sic) are subject to certain flammability requirements issued by the Consumer Product Safety Commission.; We have previously defined the term 'mattress cover' as including bot a cover that is used generally to enclose a mattress for cleanliness or sanitary purposes *and* the ticking permanently attached to the mattress to enclose the mattress filling or core. Both of these items would have to meet the requirements of Standard No. 302.; Should you have any further questions or need more information on thi subject, please contact Mr. Steve Kratzke of my staff at (202) 426- 2992.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1456OpenMr. Bruce Caulkens, Bruce Caulkens, Inc., 28500 Hayes Avenue, Roseville, MI 48066; Mr. Bruce Caulkens Bruce Caulkens Inc. 28500 Hayes Avenue Roseville MI 48066; Dear Mr. Caulkens: This is in response to your letter of April 4, 1974 requestin information concerning the existence of any Federal Motor Vehicle Safety Standards applicable to auxiliary fuel tanks.; The National Highway Traffic Safety Administration has promulgated n motor vehicle safety standard relating to auxiliary fuel tanks. There is, however, a safety standard which imposes performance requirements upon motor vehicles with regard to their fuel systems. Thus if installation of the auxiliary tank is accomplished prior to the first purchase of the vehicle for purposes other than resale causing the vehicle's fuel system not to be in compliance with the applicable safety standard, the person installing the tank or offering the vehicle for sale would be in violation of S108(a)(1) of the National Traffic and Motor Vehicle Safety Act. That would make the installer or seller subject to civil penalties of up to $1,000 for each violation.; The National Traffic and Motor Vehicle Safety Act authorizes th Secretary of Transportation to make a determination as to whether or not an item of motor vehicle equipment contains a defect which relates to motor vehicle safety. If he finds that a safety-related defect exists, he may compel the manufacturer to notify purchasers of the hazard. Therefore, even though auxiliary fuel tanks are not the subject of a standard, they still must be safely designed.; For your information, I have enclosed a copy of the Federal Safet Standard relating to motor vehicle fuel systems.; 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.