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: aiam2631OpenMr. Takeo Shimoguchi, General Manager, Daido Kogyo Co., Ltd., 1-197 Kumasaka-cho, Kaga, Ishikawa-pref., Japan; Mr. Takeo Shimoguchi General Manager Daido Kogyo Co. Ltd. 1-197 Kumasaka-cho Kaga Ishikawa-pref. Japan; Dear Mr. Shimoguchi: This responds to your April 30, 1977, comments concerning Standard No 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. Your comments question the advisability of requiring the rim size designation to be stated in the order of diameter by width. This designation would be the reverse of existing Japanese and European practices.; The National Highway Traffic Safety Administration (NHTSA) examine this issue in its response to petitions for reconsideration of Standard No. 120 (42 FR 7140). The agency determined that the rim size designation should be expressed on the label in the manner proposed in the standard (diameter by width) to avoid confusion with the tire size designation which is measured in terms of width by diameter. Since publication of our response to petitions for reconsideration (which included your petition), we have received no information presenting new reasons to alter the chosen format. Therefore, the NHTSA will continue to implement the standard as published in the February 7 Notice.; In a second question, you ask whether the NHTSA requires that th information specified in S5.2 of the standard be listed in any particular order. Although the agency has not specified the order in which the information required in S5.2 should be listed, the NHTSA expects that for purposes of clarity the information in paragraphs (a), (b), and (c) would be grouped together as would the information in paragraphs (d) and (e).; Finally, you note that the symbol 'JIS' must be marked on the rim i accordance with requirements od the Japanese Industrial Standard while NHTSA requires only the letter 'J.' For purposes of uniformity the agency will continue to require the letter 'J' even though this may result in the double marking situation to which you refer.; I trust that this responds fully to your comments. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2437OpenM. Iwase, Chief, Koito Manufacturing Co., Ltd., Shizuoka Works, 500, Kitawaki, Shimizu-Shi, Shizuoka-Ken, JAPAN; M. Iwase Chief Koito Manufacturing Co. Ltd. Shizuoka Works 500 Kitawaki Shimizu-Shi Shizuoka-Ken JAPAN; Dear Mr. Iwase: This is in response to your letter of November 2, 1976, regardin questions on Docket No. 75-8, Notice 5, for a two-lamp rectangular headlamp system. The answers are provided in accordance with the paragraph numbering of your letter.; >>>1) The two-lamp rectangular headlamps must meet the requirements o SAE J579c.<<<; This is an improved performance lamp over the requirements of SAE J579 and, therefore, must meet the requirements of SAE J579c.; >>>2) The maximum permissible candela for the Type 2B headlamp i 75,000 as specified in SAE J579c. The lower limit for other types of headlamps is retained awaiting future rulemaking action.; 3) SAE J580b as specified in the 1976 edition of the SAE Handbook i the correct reference specification for the Type 2B Sealed Beam Headlamp Assembly.; 3-1) Answered above 3-2) Answered above 3-3) Appropriate revisions to subreferenced SAE standards have at thi time not been made for the Type 2B headlamp. In the case of SAE J580b, conducting the tests with a modified deflectometer to fit the Type 2B lamp would be sufficient. It is anticipated that revisions will soon be made to the appropriate subreferenced SAE standards for the Type 2B headlamp.<<<; Your suggested revisions for the referenced and subreferenced SA standards to incorporate the Type 2B headlamp, including a modified design of deflectometer, may be sent directly to:; >>>Society of Automotive Engineers, Detroit Office, Suite 206, 210 West Big Beaver, Troy, Michigan 48084, ATTENTION: Mr. James Tishkowski<<<; We hope this clarifies the questions contained in your letter. If yo have additional questions, please do not hesitate to contact us.; Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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ID: aiam5592OpenMr. D. L. O'Connor Manager Government & Customer Compliance The Goodyear Tire & Rubber Company Akron, OH 44316-0001; Mr. D. L. O'Connor Manager Government & Customer Compliance The Goodyear Tire & Rubber Company Akron OH 44316-0001; "Dear Mr. O'Connor: This responds to your telephone conversation wit Walter Myers of my staff on July 12, 1995, followed up by your letter of July 13, 1995. You stated that Goodyear is encountering difficulties in exporting tires to Colombia, South America, in that Colombia wants verification that Goodyear complies with all Federal motor vehicle safety standards (FMVSS) when placing the DOT symbol on tires. You believe that Colombia will permit importation of Goodyear tires if NHTSA recognizes that Goodyear is a U.S. tire manufacturer in good standing and that Goodyear's placing the DOT symbol on its tires is accepted as valid certification of compliance by the U.S. government. As Mr. Myers stated in your telephone conversation, other U.S. tire manufacturers and exporters have had similar difficulties with Central and South American countries. All those countries regard the FMVSSs as acceptable assurances of tire safety, but they do not seem to understand or are skeptical of our system of manufacturer self-certification. They want assurances from a responsible U.S. government agency that manufacturer self-certifications are accepted as valid by the U.S. government. Enclosed is a statement similar to those that we have provided other manufacturers and exporters. Since the Federal government cannot and does not approve, certify or endorse vehicles and equipment, this statement is as far as we can go in getting the Federal government involved in what by law is essentially a manufacturer responsibility. I hope the enclosed statement will be helpful to you. Should you have further questions or need additional information, please feel free to contact Mr. Myers at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam1627OpenMr. Edgar E. Lungren, Jr., General Attorney, Trailmobile, 200 South Michigan Avenue, Chicago, IL 60604; Mr. Edgar E. Lungren Jr. General Attorney Trailmobile 200 South Michigan Avenue Chicago IL 60604; Dear Mr. Lungren: This responds to Trailmobile's September 27, 1974 request for determination that the combination of a new trailer main body structure (underframe, floors, side walls, and nose structure) with the rear doors, lighting components, running gear, and landing gear of a used trailer, would not constitute the manufacture of a new motor vehicle subject to Federal motor vehicle safety standards. You request this determination because motor vehicles manufactured after January 1, 1975, must comply with Standard No. 121, *Air brake systems*.; Re-use of components from an existing vehicle in the construction o another vehicle may or may not result in the manufacture of a new vehicle. The NHTSA has established that the addition of new components (such as a truck body) to the chassis of a used vehicle does not constitute the manufacture of a new vehicle. Conversely, the addition of used components to a new chassis which has never been certified in a vehicle constitutes the manufacture of a new vehicle subject to the safety standards in effect for that vehicle class on the date of manufacture. This criterion has been relied on in the area of chassis-cab multistage manufacture.; Since Trailmobile plans to utilize a new underframe as well as a ne upper structure in the construction of these trailers, we consider that the operation you describe constitutes the manufacture of a new motor vehicle for purposes of application of the safety standards, and Standard No. 121 applies to those trailers manufactured by this process on or after January 1, 1975. To conclude otherwise would mean that re- use of running gear assemblies and rear doors could indefinitely exempt a vehicle from upgraded and newly-issued safety standards.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam1949OpenMr. E. Alan Moss, Moss Motor, Ltd., P.O. Box 'MG', 5775 Dawson Avenue, Goleta, California; Mr. E. Alan Moss Moss Motor Ltd. P.O. Box 'MG' 5775 Dawson Avenue Goleta California; Dear Mr. Moss: #The President has asked me to reply to your letter o February 9, 1976, concerning the application of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*, to replacement brake hoses for MG sports cars built from approximately 1945 to 1955. #All brake hose and brake hose end fittings manufactured on or after September 1, 1974, must meet the performance and labeling requirements of Standard No. 106-74. All brake hose assemblies manufactured on or after March 1, 1975, must meet those performance and labeling requirements in the standard that apply to assemblies and, with an exception noted below, must be constructed of conforming hose and end fittings. #The Federal motor vehicle safety standards are not applicable to classic or antique card in the following sense: a standard applies only to a motor vehicle or item of motor vehicle equipment that is manufactured after its effective date. Thus, for example, there is no requirement that MG's in question be retrofitted with conforming brake hose. However, any person manufacturing brake hose for use in such a vehicle must, on and after September 1, 1974, ensure that the hose conforms. #You may find some relief in S12 of the standard. To facilitate the depletion of inventories of hose manufactured before September 1, 1974, that conforms to all aspects of the standard except the labeling requirements, this provision permits the use of such hose in assemblies manufactured before September 1, 1976. #There are no Federal motor vehicle safety standards that apply to hydraulic brake system components other than Standard No. 106-74, *Brake Hoses*, and Standard No. 116, *Motor Vehicle Brake Fluids*. #Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicle Programs; |
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ID: aiam0667OpenMr. Harry O. Youngberg, Tiny's Tire Center, 10805 Pacific Avenue, Tacoma, WA 98444; Mr. Harry O. Youngberg Tiny's Tire Center 10805 Pacific Avenue Tacoma WA 98444; Dear Mr. Youngberg: Thank you for your recent letter regarding tire identification an recordkeeping, and your suggestions for promotion of safety on the highways.; As you know the Congress set forth the requirements for tir identification and recordkeeping as a part of the National Traffic and Motor Vehicle Safety Act of 1966, amended May 22, 1970. The Safety Act specifically places responsibility for tire identification and recordkeeping upon the manufacturer with the assistance of dealers and distributors. We believe Regulation Part 574 implements this mandate of the Congress in an effective and workable manner. Hopefully it will prove to be a protective measure to the great majority of conscientious industry members who are maintaining high safety standards in their products.; This Administration, by authority of the National Highway Safety Act o 1966, is also deeply involved in a program of traffic safety standards. Periodic Motor Vehicle Inspection is the first standard in the program. Details concerning the standard are contained in the Highway Safety Program Manual Volume I, copy enclosed.; Another standard in the program entitled 'Alcohol in Relation t Highway Safety' is described in the Highway Safety Program Manual Volume 8, copy enclosed. As you know, State and local enforcement plays a major role in the success of this type of program. We acknowledge, however, that much work at the Federal level is yet to be done in this area of safety.; Standardizing automotive switches and controls is related to acciden avoidance and is covered in the series-100 of Federal motor vehicle safety standards. Please note Standards No. 101 and No. 102 in the enclosed publication.; With regard to consumer information and protection, special attentio is being given to this subject by the White House's Office of Consumer Affairs. We are enclosing a pamphlet that contains an index of Federal publications on how to buy and use consumer products.; Your interest in consumer safety and protection is very muc appreciated.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam1780OpenMr. Byron Crampton, Truck Body & Equipment Assoc., 5530 Wisconsin, (sic) Ave., Suite 1220, Washington, DC 20015; Mr. Byron Crampton Truck Body & Equipment Assoc. 5530 Wisconsin (sic) Ave. Suite 1220 Washington DC 20015; Dear Mr. Crampton: This responds to your January 3, 1975, question whether a firefightin vehicle which articulates and has a configuration similar to that a conventional truck-trailer combinations qualifies as a 'truck' for test purposes under Standard No. 121, *Air brake systems*. You describe the vehicle as a tractor trailer aerial ladder with articulating portions that cannot be uncoupled, and with permanently-connected air brake lines and hydraulic pressure lines between the articulating sections.; The vehicle you describe is a 'truck' as that term is defined in 49 CF S 571.3, *Definitions*. The rear articulated portion does not qualifiy (sic) as a 'trailer' as defined in S571.3, because the permanent connection to the truck tractor prevents it from standing alone as a 'vehicle'. Therefore, the tractor trailer aerial ladder would be tested as a truck under Standard No. 121. It is noteworthy that the lighting requirements which apply to the rear portion of this vehicle are those for trucks under Standard No. 108, *Lamps reflective devices, and associated equipment*.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5528OpenMr. James M. Hanson Chairman Engineering Committee Transportation Safety Equipment Institute 1325 Pennsylvania Ave., N.W. Washington, D.C. 20004; Mr. James M. Hanson Chairman Engineering Committee Transportation Safety Equipment Institute 1325 Pennsylvania Ave. N.W. Washington D.C. 20004; Dear Mr. Hanson: This replies to your letter of April 7, 1995, askin for an interpretation of the applicability requirements of paragraph S5.7 of Motor Vehicle Safety Standard No. 108. The conspicuity requirements of S5.7 apply to 'each trailer of 80 or more inches overall width and with a GVWR over 10,000 lbs.' You state that the word 'and' in this paragraph 'could cause some trailer manufacturers to think that both conditions must be present before tape is applied on the trailer', and that some manufacturers could interpret this to avoid applying tape to trailers of the specified width but less than the specified GVWR and vice versa. We have no objection to a manufacturer's applying conspicuity treatment to trailers of any width or GVWR. However, as S5.7 clearly states, a manufacturer is not required to comply with the conspicuity requirements unless its trailer is at least 80 inches in overall width and has a GVWR over 10,000 pounds. If you desire further clarification on this matter, you may call Taylor Vinson of this Office (202-366-5263). Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam5527OpenMr. James M. Hanson Chairman Engineering Committee Transportation Safety Equipment Institute 1325 Pennsylvania Ave., N.W. Washington, D.C. 20004; Mr. James M. Hanson Chairman Engineering Committee Transportation Safety Equipment Institute 1325 Pennsylvania Ave. N.W. Washington D.C. 20004; Dear Mr. Hanson: This replies to your letter of April 7, 1995, askin for an interpretation of the applicability requirements of paragraph S5.7 of Motor Vehicle Safety Standard No. 108. The conspicuity requirements of S5.7 apply to 'each trailer of 80 or more inches overall width and with a GVWR over 10,000 lbs.' You state that the word 'and' in this paragraph 'could cause some trailer manufacturers to think that both conditions must be present before tape is applied on the trailer', and that some manufacturers could interpret this to avoid applying tape to trailers of the specified width but less than the specified GVWR and vice versa. We have no objection to a manufacturer's applying conspicuity treatment to trailers of any width or GVWR. However, as S5.7 clearly states, a manufacturer is not required to comply with the conspicuity requirements unless its trailer is at least 80 inches in overall width and has a GVWR over 10,000 pounds. If you desire further clarification on this matter, you may call Taylor Vinson of this Office (202-366-5263). Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam2595OpenMr. James R. Green, 3396 Alma Street, Lynwood, CA 90262; Mr. James R. Green 3396 Alma Street Lynwood CA 90262; Dear Mr. Green: Your letter of April 8, 1977, to the President of the United State concerning the need for improved motor vehicle headlamp standards has been referred to this office for consideration and reply.; We have received considerable information regarding the effects o foreign and domestic motor vehicle headlighting equipment, including engineering papers and test data on 'selective yellow' headlamps. All information concluded that filtering of headlamps to produce yellow reduces the photometric intensity of the lamp, thereby reducing the actual seeing distance. Some vehicle operators subjectively concluded they can see further with yellow headlamps, but objective seeing distance tests with specific target characteristics and distances indicate a loss of seeing distance.; It is also true that while the original intent in using yello headlamps was to reduce the glare from oncoming vehicle headlamps, our current test data indicates that a yellow light does not reduce glare. The white light is, therefore considered safer and is the basis for requiring white light in Federal Motor Vehicle Safety Standard No. 108 (copy enclosed).; Although this lighting standard is generally in accordance wit standards developed and published by the Society of Automotive Engineers, it does not specifically require sealed-beam headlamps. However, it does require headlamps which are designed to be aimed properly when installed in prealigned mechanical assemblies. The lamp itself may be sealed-beam (filament is enclosed only by the lamp shell in an inert atmosphere) or it may be a halogen lamp (filament is surrounded by a small envelope containing a halogen gas). Specifically, the halogen-bulb headlamp is legal if incorporated into an otherwise legal motor vehicle headlamp.; I trust the foregoing is fully responsive to your inquiry. Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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.