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: aiam3010OpenMr. M. Iwase, Chief, Overseas Technical Section, Technical Administration Department, Koito Manufacturing Co., Ltd., Shizuoka Works, 500, Kitawaki, Shimizu-Shi, Shizuoka-Ken, JAPAN; Mr. M. Iwase Chief Overseas Technical Section Technical Administration Department Koito Manufacturing Co. Ltd. Shizuoka Works 500 Kitawaki Shimizu-Shi Shizuoka-Ken JAPAN; Dear Mr. Iwase: This is in reply to your letter of January 29, 1979, to Bill Eason wit respect to headlamp lens marking. Mr. Eason is no longer associated with the Office of Rulemaking and we regret the delay in writing you.; You have asked for a confirmation of your interpretation that: >>>'The headlamp designed to conform to J579c shall be provided wit the lens marking specified in S4.1.1.21 of FMVSS No. 108 *even if the upper beam headlamp maximum output is lower than the conventional maximum restriction of 37,500 cd*.'<<<; You are correct that S4.1.1.21 permits the new code marking fo headlamps designed to conform to SAE Standard J579c even if the upper beam headlamp maximum output is lower than the maximum of 75,000 cds permissible under J579c or the previous maximum of 37,500 cd of J579a. But because the code could be misleading, we are considering proposing an amendment of Standard No. 108 that would delete the new code requirement for all headlamps whose maximum candela does not exceed a certain value, such as 40,000 cd.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2563OpenMr. L. Wenderoth, Bandag of Nassau, Inc., 40 Brook Avenue, Deer Park, NY 11729; Mr. L. Wenderoth Bandag of Nassau Inc. 40 Brook Avenue Deer Park NY 11729; Dear Mr. Wenderoth: This responds to your March 10, 1977, letter asking whether it i permissible for you to use a DOT number assigned to another tire retreader when you perform special retread work in your plant for the other retreader who lacks facilities to do the work himself.; Standard No. 117, *Retreaded Pneumatic Tires*, requires that th retreader apply a DOT symbol and identification number to the tire. The DOT symbol indicates conformance with Federal regulations. The number enables the National Highway Traffic Safety Administration (NHTSA) to identify the retreader that manufactures the tire. To permit one manufacturer to use the identification number of another would impair the NHTSA enforcement actions. Accordingly, you would not be permitted to use any DOT number other than your own on tires you retread.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2558OpenMr. L. Wenderoth, Bandag of Nassau, Inc., 40 Brook Avenue, Deer Park, New York 11729; Mr. L. Wenderoth Bandag of Nassau Inc. 40 Brook Avenue Deer Park New York 11729; Dear M. Wenderoth: This responds to your March 10, 1977, letter asking whether it i permissible for you to use a DOT number assigned to another tire retreader when you perform special retread work in your plant for the other retreader who lacks facilities to do the work himself.; Standard No. 117, *Retreaded Pneumatic Tires*, requires that th retreader apply a DOT symbol and identification number to the tire. The DOT symbol indicates conformance with Federal regulations. The number enables the National Highway Traffic Safety Administration (NHTSA) to identify the retreader that manufactures the tire. To permit one manufacturer to use the identification number of another would impair the NHTSA enforcement actions. Accordingly, you would not be permitted to use any DOT number other than your own on tires you retread.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2385OpenMr. J. J. Cowley, Imperial Chemical Industries Limited, P.O. Box No. 90, Wilton Middlesborough, Cleveland TS6 8JE, England; Mr. J. J. Cowley Imperial Chemical Industries Limited P.O. Box No. 90 Wilton Middlesborough Cleveland TS6 8JE England; Dear Mr. Cowley: This responds to your July 2, 1976, question whether evaluation of th lubricity of DOT 4 brake fluid by the Society of Automotive Engineers (SAE) modified stroking test (SAE J1703f) is consistent with the requirements of Standard No. 116, *Brake Fluids*.; Standard No. 116 specifies that the stroking properties of DOT 4 brak fluids be tested by use of the apparatus described in SAE Standard J1703b. This is the procedure that would be used in a determination of whether a certain brake fluid conforms to the requirements of Standard No. 116. Section 571.5 of our regulations (49 CFR Part 571) provides that materials subject to change are incorporated into a standard as provided in the standard or, if no indication is made, as of the date of adoption of Part 571. In this case, the standard indicates that J1303b is the version of the SAE practice that has been incorporated.; This does not mean that you cannot use the modified SAE procedure fo purposes of your certification testing. Your obligation as a manufacturer is to ensure that your certification of compliance is not false or misleading in a material respect, and that you have exercised due care in manufacturing to conform to Standard No. 116 (15 U.S.C. S 1397(b) (2)). A manufacturer is not required to follow specifically the test procedures of the standards. Rather, he must ascertain, in the exercise of due care, that his product will conform to the requirements of the standard when it is tested by the stated methods. The NHTSA cannot approve a manufacturer's test procedure as the basis of due care in advance of the actual events that underlie certification.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam3474OpenMr. T. Takano, Chief of Development Dept., Meiji Rubber & Chemical co., Ltd., Kojima Building, 10-2, Nishishinjuku, 1-Chome, Shinjuku-Ku, Tokyo, Japan; Mr. T. Takano Chief of Development Dept. Meiji Rubber & Chemical co. Ltd. Kojima Building 10-2 Nishishinjuku 1-Chome Shinjuku-Ku Tokyo Japan; Dear Mr. Takano: This responds to your recent letter regarding the use of flexible nylo tubes in vacuum braking systems. You ask whether such plastic hoses would qualify as 'vacuum tubing connectors' for purposes of Safety Standard No. 106, *Brake Hoses*.; We recently received a letter asking this identical question from Toka Rubber Industries of Japan. I am enclosing a copy of that letter for your information. I believe that it will answer all of your questions. You will see from the letter that these nylon tubes cannot qualify as 'vacuum tubing connectors' and must comply with the requirements of Safety Standard No. 106.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1786OpenMr. J.C. Eckhold,Ford Motor Company,Dearborn, Michigan 48121; Mr. J.C. Eckhold Ford Motor Company Dearborn Michigan 48121; Dear Mr. Eckhold:#This responds to your letter of December 19, 1974, t Dr. Gregory, requesting confirmation of your interpretation of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*.#You described a brake booster system which combines vacuum and hydraulic boost, with the latter supplied by the power steering pump. In a Federal Register notice on June 28, 1974 (39 FR 24012, Docket No. 1-5, Notice 11) the NHTSA exempted certain hydraulic booster hoses from the requirements of Standard No. 106-74. Although no power steering fluid accumulator is used, the hydraulic booster hose which you described is exempt from the requirements of the standard because of the presence of redundant booster power supplied by the independent vacuum booster system.#A future amendment to Standard No. 106-74 to eliminate ambiguity respecting the standard's applicability to hydraulic booster hoses is currently under consideration.#Yours truly,Richard B. Dyson,Acting Chief Counsel; |
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ID: aiam1362OpenMr. Arden H. Faris, Assistant Director, American Retreader's Association, Inc., P.O. Box 17203, Louisville, Kentucky 40217; Mr. Arden H. Faris Assistant Director American Retreader's Association Inc. P.O. Box 17203 Louisville Kentucky 40217; Dear Mr. Faris: This is in reply to your letter of November 20, 1973, asking under wha conditions retreaded tires, which you describe as, 'not first class mainly from the standpoint of appearance,' may be sold. You state that the tires are not defective, and are being sold for non-highway use, such as for farm wagons and hay bailers.; Standard No. 117 (Retreaded pneumatic tires) applies to all retreade tires manufactured for use on passenger cars. The sale of such tires for off-highway vehicular purposes does not remove them from the coverage of the standard. Consequently, the tires must comply fully with Standard No. 117, bear the manufacturer's identification number (49 CFR Part 574), and not be restricted to off-road operation.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam1544OpenMr. Kevin J. Adams, Director, Department of Parking & Transit Facilities, University of Virginia, 408 Brandon Avenue, Charlottesville, VA 22903; Mr. Kevin J. Adams Director Department of Parking & Transit Facilities University of Virginia 408 Brandon Avenue Charlottesville VA 22903; Dear Mr. Adams: This is in reply to your letter of May 28, 1974, asking whether ther are any Federal laws that would have a bearing on the University of Virginia's contemplated decision to purchase a tire grooving machine to regroove tires that will be used on buses operated by the University.; The NHTSA has recently amended Federal 'Regrooved Tire' regulations (4 CFR 569, copy enclosed) to prohibit any person from regrooving his own tires (49 CFR S 569.7). The regulation would apply to the University with respect to the tires you contemplate regrooving for use on university buses, and should certainly bear on your decision to purchase a tire regrooving machine.; The amendment to the regulation resulted from litigation *(Nationa Association of Motor Vus Owners* v. *Brinegar*, 483 F.2d 1294 (D.C. Cir. 1973)) in which the United States Court of Appeals held that under section 204 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1524) Congress authorized this agency to permit only the sale of regrooved tires.; There are presently some efforts being made in the Congress to amen the Safety Act to alter the effect of this court deicsion. No final action of any kind has been taken, however, and we do not know whether or when such action might be taken.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam0744OpenMr. Frank R. Raidl, Vice President, All Brake & Drive Unit Service, Inc., 5551 Ogden Avenue, Cicero, IL 60650; Mr. Frank R. Raidl Vice President All Brake & Drive Unit Service Inc. 5551 Ogden Avenue Cicero IL 60650; Dear Mr. Raidl: This is in response to your letters of February 14 and April 20, 1972 I apologize for our delay in answering your inquiries. You state that your G.M.C. truck dealership installs fifth wheels, saddle gas tanks, mirrors, marker lamps and tractor protection brake equipment and you inquire what your obligations are with respect to the Manufacturer Identification and Certification regulations (Parts 566 and 577 (sic) respectively).; Installation of fifth wheels would make you a 'final-stag manufacturer', as defined in Part 568, Vehicles Manufactured in Two or More Stages, because you perform 'such manufacturing operations on an incomplete vehicle that it becomes a completed vehicle', other than the addition of 'readily attachable components, such as mirror or tire and rim assemblies.' Installation of the other items you listed would generally not make you a final-stage manufacturer, since installation of these items does not fulfill the above criteria.; As a final-stage manufacturer, you are required under Part 566 Manufacturer Identification, to submit the information specified in S566.5. Your submittal of January 18, 1972, satisfies this requirement.; As a final-stage manufacturer, you are also required under part 567 Certification, to affix a certification label on the vehicle you manufacture. In addition, Part 573 requires the submission of quarterly reports regarding vehicle production and defect notifications (49 CFR S 573.5) and of copies of all other notices, bulletins and communications sent to more than one dealer or purchaser regarding any defect in such vehicles, whether or not safety-related.; I am enclosing copies of Parts 566, 567, 568, and 573 for you information. These should also answer your questions as to the format of the required submittals.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3030OpenMr. Donald I. Reed, Director of Engineering, Trailer Manufacturer Association, 401 North Michigan Avenue, Chicago, IL 60611; Mr. Donald I. Reed Director of Engineering Trailer Manufacturer Association 401 North Michigan Avenue Chicago IL 60611; Dear Mr. Reed: This letter corrects an interpretation provided you on June 1, 1979. In our letter, we answered in the negative to your question whether: >>>'whether (sic) it is permissible to combine a clearance lam function in a tail lamp fixture if a second bulb is installed in the tail lamp which, when lit alone, satisfies the photometric requirements of the clearance lamp shown through the tail lamp lens ... and further assuming that all tail lamp photometric requirements are met when the tail lamp bulb alone is lit and when both lamps are lit.'<<<; We commented that such a lamp would appear to create the optica combination prohibited by S4.4.1 when both lamps are lit.; It has been brought to our attention that this conflicts wit interpretations provided on March 4, 1977, to Dennis Moore of Livermore, California, and B.R. Weber of West Bend, Wisconsin, both manufacturers of boat trailer lighting equipment. In our letter to Mr. Weber, for example, we interpreted 'optically combined' to mean a situation in which 'the same light source (i.e., bulb) and the same lens area fulfill two or more functions (i.e., tail lamp, and stop lamp, clearance lamp and turn signal lamp)'. The phrase is not intended to prohibit the installation of two separate bulbs in a single housing and covered by a common lens.; Upon review, we believe that the interpretation of March 4, 1977, i the correct one, and that the conflicting interpretation of June 1, 1979, should be with error. We are sorry for any confusion this may have caused your members.; 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.