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: aiam5577OpenMr. Shih-Chiang Chen President Top World Traffic Equipments Co., Ltd. 7F-1. No/ 286-9, Hsin Ya Road Chien Chen Dist. Kaohsiung Taiwan R.O.C.; Mr. Shih-Chiang Chen President Top World Traffic Equipments Co. Ltd. 7F-1. No/ 286-9 Hsin Ya Road Chien Chen Dist. Kaohsiung Taiwan R.O.C.; Dear Sir: This is in reply to your letter of June 15, 1995, to th Department of Transportation regarding your invention, the 'brake condition warning sensor.' You ask whether such an invention is permissible in this country. The sensor causes flashing in 'the third brake light' keyed to the rate of deceleration. Under the Federal regulations in the United States, motor vehicles must be manufactured so that the third brake light (or 'center highmounted stop lamp' as we call it) and all other stop lamps are steady-burning when they are in use. After the vehicle is sold, Federal law prohibits any manufacturer, dealer, distributor, or motor vehicle repair business from installing the sensor to modify the performance of the third brake light and cause it to flash. However, Federal law does not prohibit the owner of the car from installing the sensor. In this circumstance, the law of the State in which the vehicle is operated must be consulted to determine whether a flashing third brake light is permissible. We are not able to answer questions about State laws. If you wish an opinion on State laws governing flashing third brake lights, you should write the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. If I can be of further assistance, please contact me or Mr. John Womack Acting Chief Counsel (202) 366-9511. Sincerely, Ricardo Martinez, M.D.; |
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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: aiam1105OpenMr. C. A. Wilson, Examiner, Casualty-Property Division, The Travelers, One Tower Square, Hartford, CT 06115; Mr. C. A. Wilson Examiner Casualty-Property Division The Travelers One Tower Square Hartford CT 06115; Dear Mr. Wilson: This is in reply to your letter of March 30, 1973, concerning th applicability of the Federal odometer disclosure requirements (49 CFR Part 580) to transactions in which an insurance company takes possession of a vehicle after declaring it a total loss and paying the owner's claim, and subsequently transfers the vehicle to a salvage dealer.; You are correct in understanding that transactions of this sort are no exempt under section 580.5 of the regulation. When the owner transfers the vehicle to the insurer, he is required to make disclosure statement, and the insurer, in turn, is required to make disclosure upon sale to the salvage dealer. As a practical matter, however, if the vehicle is so badly damaged that it is unlikely ever to be returned to the road, it will have ceased to be a motor vehicle, for purposes of this regulation. Disclosure would therefore not be required.; In cases where the vehicle is repairable or undamaged, as is often th situation in the recovery of stolen vehicles, a disclosure statement should be given as in any other motor vehicle transaction.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4947OpenGordon W. Didier, Esquire Butzel Long Suite 200 32270 Telegraph Birmingham, Michigan 48010-4996; Gordon W. Didier Esquire Butzel Long Suite 200 32270 Telegraph Birmingham Michigan 48010-4996; "Dear Mr. Didier: This responds to your request for an interpretatio of Federal Motor Vehicle Safety Standard No. 118 Power Windows (49 CFR 571.118), on behalf of your client, a manufacturer of automobile sunroofs. As you noted in your letter, the agency has published a final rule amending Standard No. 118 in the April 16, 1991 edition of the Federal Register (56 FR 15290). You requested clarification of certain requirements in that final rule. The agency has received several petitions for reconsideration of the final rule amending Standard No. 118. The agency is currently reviewing the merits of each petition. The agency will issue a notice in the Federal Register granting and/or denying the petitions. In that notice, the agency will also address the concerns raised in your request for an interpretation on Standard No. 118. Please let us know if you have any questions about the issues raised in your letter after our response to the petitions for reconsideration has been published and you have had the opportunity to review it. If you need more information on this subject, please feel free to contact Dorothy Nakama of my staff at this address, or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam4951OpenMr. Cliff Chuang, President Prospects Corporation 2790 Upper Ridge Dr. #2 Rochester Hills, MI 48307; Mr. Cliff Chuang President Prospects Corporation 2790 Upper Ridge Dr. #2 Rochester Hills MI 48307; "Dear Mr. Chuang: This responds to your request for an interpretatio of Federal Motor Vehicle Safety Standard No. 118 Power Windows (49 CFR 571.118). As you noted in your letter, the agency has published a final rule amending Standard No. 118 in the April 16, 1991, edition of the Federal Register (56 FR 15290). You requested clarification of certain requirements in that final rule. The agency has received several petitions for reconsideration of the final rule amending Standard No. 118. One such petition is from your company. The agency is currently reviewing the merits of each petition. The agency will issue a notice in the Federal Register granting and/or denying the petitions. In that notice, the agency will also address the concerns raised in your request for an interpretation of Standard No. 118. Please let us know if you have any questions about the issues raised in your letter after our response to the petitions for reconsideration has been published and you have had the opportunity to review it. If you need more information on this subject, please feel free to contact Dorothy Nakama of my staff at this address, or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam1183OpenMr. Rene Politis, Director, Product Reliability and Assurance Department, Signal-Stat Corporation, 1200 Commerce Avenue, Union, NJ 07083; Mr. Rene Politis Director Product Reliability and Assurance Department Signal-Stat Corporation 1200 Commerce Avenue Union NJ 07083; Dear Mr. Politis: This is in reply to your letter of July 10, 1973, to Mr. Schneide asking which SAE Standard incorporated into Standard No. 108 applies to turn signal operating units, SAE J589 or J589a.; The correct standard is SAE J589. You noted that the tables in th standard refer to J589, while paragraph S5.1 states that subreferenced standards shall be those published in the 1970 edition of the SAE Handbook. The key word in S5.1 is '*sub*referenced', *i.e.*, referred to only in an SAE standard itself referenced in the Federal standard. J589 is directly referenced, not subreferenced and the number identified is correct. An example of a subreferenced standard would be J575, which is mentioned in J589.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2808OpenMr. Bruce Baldwin Mohs, President, Mohs Seaplane Corporation, 2355 University Avenue, Madison, WI 53705; Mr. Bruce Baldwin Mohs President Mohs Seaplane Corporation 2355 University Avenue Madison WI 53705; Dear Mr. Mohs: This is in reply to your letter of May 5, 1978, asking 'what i necessary for the rewriting of [Motor Vehicle Safety Standard No.] 108 to include my . . . system for vehicle identification.' As you have described this reflective device, it is a polyvinyl extrusion in which is placed polyester tape which 'becomes a continuous reflector down the side of a vehicle - amber toward the front, red on the rear half of the vehicle and red across the back.' You state that in your experimental installation you are 'retaining the 3' spot reflectors as required in Standard 108.'; If your material conforms to Federal Specification L-S-300 and, as use on the vehicle, meets the performance standards in Table 1 of SAE Standard J495d, 'Reflex Reflectors,' March 1967, it could be used as the front and rear reflex reflectors required by Standard No. 108. However, if it does not meet this specification, Standard No. 108 would not prohibit the sale and installation of your system as original equipment, or as an aftermarket accessory, provided it is supplementary to the side and rear reflectors required by Standard No. 108. Thus, no Federal 'approval' of your system is required. A change in Standard No. 108 is required only if you believe your system should be mandatory on all motor vehicles. In the event you wish to petition for such an amendment of Standard No. 108, I enclose a copy of our rulemaking procedures.; Yours truly, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2983OpenMr. Lawrence B. Leiby, 295 Spring Street, Box 551, Shreve, OH 44676; Mr. Lawrence B. Leiby 295 Spring Street Box 551 Shreve OH 44676; Dear Mr. Leiby: This is in reply to your letter of February 7, 1979, to the Departmen asking about the legality of wiring the rear hazard warning signals so that they automatically flash when the gear shift level is placed in reverse.; We are able to give you guidance about applicable Federal law only. Th Federal requirements for new motor vehicles are set forth in Federal Motor Vehicle Safety Standard No. 108 (49 Code of Federal Regulations 571.108). As you probably know, the hazard warning system and the turn signal system typically use the same lights. There is no provision in the standard which prohibits a manufacturer from wiring the rear hazard signals/turn lights so that they flash when the vehicle gear shift is in reverse. Please note, however, that the standard (S4.6(b)) requires the separate rear tail lamps to be steady burning. Thus, those lamps may not be wired so that they flash.; As for modification of used vehicles, contact the State in which th modified vehicle would be licensed and operated to determine if it has any applicable vehicle-in-use laws.; We appreciate your interest in motor vehicle safety. Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam0644OpenMr. Gorou Utsunomiya, Chief, Liaison Engineer, Toyo Kogyo Detroit Office, 3841 Mystic Valley Dr., Bloomfield Hills, Michigan 48013; Mr. Gorou Utsunomiya Chief Liaison Engineer Toyo Kogyo Detroit Office 3841 Mystic Valley Dr. Bloomfield Hills Michigan 48013; Dear Mr. Utsunomiya: This is in response to your letter of March 16, 1972, in which you as whether the definition of 'unloaded vehicle weight' is the same as or 'curb weight' plus optional parts, and whether the definition of 'gross vehicle weight' is the same as that for 'maximum loaded vehicle weight.'; The two sets of definitions are expressed in substantially differen terms. The new terms, 'unloaded vehicle weight' and 'gross vehicle weight rating' are more general than the older ones. The newer terms also eliminate some ambiguities in the definitions based on 'curb weight,' such as just what is meant by 'standard equipment,' and whether other vehicle fluids besides fuel, oil, and coolant should be included. Further, GVWR is a rating, not necessarily identical to any scale weight although some constraints have been placed on it in our Certification regulations (S567.4(g)(3)).; Thus although the two sets of definitions are somewhat similar in thei application, they are different enough that each must be interpreted and used in its own terms.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3046OpenMr. Paul Schuil, 27 Seneca Avenue, Emerson, NJ 07630; Mr. Paul Schuil 27 Seneca Avenue Emerson NJ 07630; Dear Mr. Schuil: This responds to your recent letter asking whether smoked, tinted an mirrored windows may legally be used on vehicles operating on U.S. highways.; The Federal requirements for glazing materials on motor vehicles ar set forth in the Federal Motor Vehicle Safety Standard No. 205 (49 CFR 571.205). This standard specifies performance requirements for the various types of glazing and also the locations in vehicles in which each glazing type may be used. Smoked, tinted and mirrored glazing may be used in certain vehicles in certain locations. For example, smoked glass may be used in side windows of trucks and buses. However, glazing material for use in any vehicle at levels requisite for driving visibility (e.g., windshields) must have a luminous transmittance of at least 70 percent. Most smoked glass would not pass this requirement. I am enclosing a copy of Safety Standard No. 205 for your information. If you have any questions after reviewing the standard, contact Hugh Oates of my office (202-426-2992).; Sincerely, Frank Berndt, 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.