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: aiam1459OpenMr. Robert L. Carleton, President, Timpte, Inc., 5990 Washington Street, Denver, CO 80216; Mr. Robert L. Carleton President Timpte Inc. 5990 Washington Street Denver CO 80216; Dear Mr. Carleton: This responds to your April 2, 1974, request for a procedure to permi the manufacture of semi- trailers which do not comply with Standard No. 121, *Air brake systems*, after the standard's effective date.; Our authority to enforce standards under S108(a)(1) of the Nationa Traffic and Motor Vehicle Safety Act of 1966 prohibits the sale of a vehicle which does not comply with applicable standards. We are unable to permit by regulation what is prohibited by this section of the law.; We do have under consideration petitions to delay the effective date o Standard 121 as it applies to trailers.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2062OpenMr. William J. Kronschnabel, Imperial-Eastman Corporation, 1440 North 24th Street, Manitowoc, Wisconsin 54220; Mr. William J. Kronschnabel Imperial-Eastman Corporation 1440 North 24th Street Manitowoc Wisconsin 54220; Dear Mr. Kronschnabel: #This is in response to your letter of May 28 1975, in which you petitioned for the replacement of the 'permanent' labeling requirement for brake hose in Standard No. 106-74 with a 'weather resistant' test requirement. You also asked whether a series of dots may be included after the required date information on the hose, to indicate in coded form the day of manufacture. #With respect to your petition, this agency is reconsidering the permanency requirement for the labeling, and a notice is planned for issuance shortly on that subject. We do not find an additional test requirement for the labeling to be justified, on the basis of data presently before the agency, since the usefulness of the labeling is limited primarily to the preassembly period. Therefore, in the strict sense, your petition is hereby denied. You may find, however, that the changes now being developed in our rulemaking proceedings will resolve your problems in this area. #The standard does not permit the use of coded dots indicating production date in the location specified for the required information. S5.2.2(c) specified the following information as part of the required label: #>>>The month, day and year, or the month an year of manufacture, expressed in numerals. For example, 10/1/74 means October 1, 1974.<<<# Our interpretation of S5.2 (as incorporated in S7.2) is that the required information may not be interrupted by optional information. Therefore, the day of manufacture, if indicated as part of the S5.2.2 legend, must be expressed in numerals. You may, of course, use the coded dots if they appear on the opposite side of the hose. #Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicle Programs; |
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ID: aiam2344OpenMr. Glenn W. Dobrick, Chief Engineer, Kentucky Manufacturing Company, P.O. Box 8186, 2601 South Third Street, Louisville, KY 40208; Mr. Glenn W. Dobrick Chief Engineer Kentucky Manufacturing Company P.O. Box 8186 2601 South Third Street Louisville KY 40208; Dear Mr. Dobrick: This responds to Kentucky Manufacturing Company's June 17, 1976 question whether the replacement of the frame of a converter dolly constitutes the manufacture of a new vehicle subject to applicable motor vehicle safety standards when the running gear (the axles, wheels, suspension, and related components sometimes known as a bogie) and the fifth wheel of the damaged converter dolly are reused. This office received clarification from you by telephone that the fifth wheel would be reused, although this was not stated in your letter.; The replacement of the frame is considered a repair by the Nationa Highway Traffic Safety Administration and not the manufacture of a new vehicle. Thus the operation you describe would not constitute the manufacture of a new trailer that would require certification of compliance with safety standards such as Standard No. 121, *Air Brake Systems*.; I have enclosed a copy of a recent amendment of NHTSA regulations tha permits the rebuilding of trailers without certification in some cases when it was previously prohibited. The details of the conditions under which such rebuilding is allowed are discussed in the preamble of the document.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam2080OpenMr. John F. McCuen, Counsel, Kelsey-Hayes Company, Romulus, MI 48174; Mr. John F. McCuen Counsel Kelsey-Hayes Company Romulus MI 48174; Dear Mr. McCuen: This responds to Kelsey-Hayes Company's July 28, 1975, question askin whether the requirements of S5.1.6 of Standard No. 121, *Air Brake Systems*, that specify a warning signal 'in the event of a total electrical failure of the antilock system' would permit installation on a vehicle of an antilock-equipped axle that has no capability signal electrical failure of its antilock system. You state that the vehicle would be equipped with antilock systems on other axles that would provide a warning signal in the event of their electrical failure.; The answer to your question is yes. As you noted in your letter, th National Highway Traffic Safety Administration has interpreted the specifications of S5.1.6 to require a signal only in cases where electrical failure within the antilock electrical system circuity causes loss of antilock control of every wheel on the vehicle. In the design you describe, the signal which activates upon loss of antilock control at one or more wheels on the vehicle would fulfill this requirement, because it would always activate by the time antilock control had been lost at every wheel on the vehicle. Under our interpretation of S5.1.6, a failure of antilock only on the axle described by you would not constitute 'loss of antilock control of every wheel on the vehicle' and would not be required to be signaled.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2402OpenMr. R. L. Ratz, Product Safety Engineer, The Flxible Company, 970 Pittsburgh Drive, Delaware, OH, 43015; Mr. R. L. Ratz Product Safety Engineer The Flxible Company 970 Pittsburgh Drive Delaware OH 43015; Dear Mr. Ratz: This is in reply to your letter of September 7, 1976, to Mr. Dyson formerly of this office, requesting a confirmation that an interpretation of Motor Vehicle Safety Standard No. 108, rendered to the Southern California Rapid Transit District on August 5, 1974, is still valid, and that it can be extended to include identification lamps as well.; In our earlier letter we advised the District that the installation o wiring by a manufacturer enabling a purchaser to connect it to normally steady-burning clearance lamps, enabling them to be flashed to signal a crime in progress would not violate S4.6(b) which requires clearance lamps to be steady-burning, or S4.1.3 that prohibits installation of motor vehicle equipment which impairs the effectiveness of the lighting equipment required by Standard No. 108. This will confirm that that interpretation is still valid.; Your letter, however, raises two additional issues which deserve to b answered for the record. The first is whether the bus manufacturer rather than the purchaser may make the connection, and the second is whether identification lamps may also be included in the warning system. Since it is our opinion that use of the clearance lamps in an emergency mode creates an item of lighting equipment not required by Standard No. 108 and hence outside its coverage, we have concluded that the manufacturer may connect both clearance and identification lamps to the emergency circuit without any resultant nonconformances with S4.6(b) and S4.1.3.; I hope this is responsive to your request. Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0708OpenWilliam J. Henrick, Esq., The General Tire & Rubber Company, One General Street, P.O. Box 951, Akron, Ohio 44309; William J. Henrick Esq. The General Tire & Rubber Company One General Street P.O. Box 951 Akron Ohio 44309; Dear Mr. Henrick: #In response to your letter of May 1, 1972, we woul consider a tire with a cord carcass angle of 85 degrees to be within the definition of 'radial ply tire' as that term is defined in Motor Vehicle Safety Standard No. 109. #Sincerely, Richard B. Dyson; |
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ID: aiam2097OpenMr. Walter C. Robbins, Jr., Walt Robbins, Inc., 6121 Lincolnia Road, Alexandria, Virginia 22312; Mr. Walter C. Robbins Jr. Walt Robbins Inc. 6121 Lincolnia Road Alexandria Virginia 22312; Dear Mr. Robbins: This is in response to your letter of June 5, 1975, enclosing a copy o your patent for a tire described as a 'Radial, Bias Ply Tire' and requesting an interpretation of the labeling requirements of Federal Motor Vehicle Safety Standard No. 109, *New Pneumatic Tires--Passenger Cars*. The tire would be constructed with three full body plies: two bias plies (angle 35 degrees) and on radial ply (angle 90 degrees).; S4.3(g) of the standard requires permanent molding of the word 'radial into or onto both sidewalls if the tire is a radial ply tire and, by implication, prohibits the use of the word 'radial' if the tire is not a radial ply tire. In S3., 'radial ply tire' is defined as:; >>>a pneumatic tire in which the ply cords which extend to the bead are laid at substantially 90 degrees to the centerline of the tread.<<<; The tire you have described is not within the scope of this definitio because it includes ply cords extending to the beads which are not laid at substantially 90 degrees to the centerline of the tread. Therefore, the word 'radial' must not appear on either sidewall.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2209OpenMr. Lonnie Goddard, Northern Coach, Inc., Box 190, Auburndale, WI 54412; Mr. Lonnie Goddard Northern Coach Inc. Box 190 Auburndale WI 54412; Dear Mr. Goddard: I am writing to confirm your telephone conversation of February 25 1976, with Mark Schwimmer of this office, concerning the certification of school buses.; As Mr. Schwimmer explained, this agency does not certify or otherwis issue advance approvals of motor vehicles or motor vehicle equipment. Certification, under the applicable law and regulations, must be done by the vehicle manufacturer, including a final-stage manufacturer such as you. Your certification obligation, as a final stage manufacturer of school buses, is met if you fulfill the requirements of 49 CFR Part 567, with which I understand you are already familiar.; An information sheet entitled 'Where to Obtain Federal Motor Vehicl Safety Standards and Regulations' is enclosed for your convenience. Please write if we can be of any further assistance.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1776OpenMr. Donald W. Taylor, Manager, Product Quality and Safety, Volvo of America Corporation, Rockleigh, NJ 07647; Mr. Donald W. Taylor Manager Product Quality and Safety Volvo of America Corporation Rockleigh NJ 07647; Dear Mr. Taylor: This is in response to your letter of December 26 regarding th proposed plan for notifying vehicle owners involved in defect notification campaign 74-0246.; The provisions of the 1974 amendments to the Safety Act do apply t this campaign, and notification of the defect must be in accordance with these amendments. Section 153(c)(1) requires notification to be sent to each person registered under State law as the owner of the vehicle. There is nothing in the statute to prevent a manufacturer from utilizing his own car inventory and owner files to obtain this information, however, the manufacturer must still ensure that his notification program will reach all 'registered owners.' He may not substitute, as your letter implicitly requests, notification to only those purchasers reflected on his own lists unless he can demonstrate that his lists contain a complete listing of owners registered under State law.; It is difficult to see how this can be demonstrated unless ever vehicle subject to the campaign is accounted for almost immediately after notification is mailed. Otherwise, a manufacturer would not know that he had notified each registered owner even if in fact he had. A manufacturer who delayed additional notification until the results of the first mailing were available to him (unless they were available almost immediately) would not, in our view, have issued notification within a reasonable time if in fact some owners did not receive notification as a result of the initial mailing. Thus, while the expense of purchasing owner lists would seem to be less productive in the situation you describe than in campaigns involving older vehicles, it is difficult for us to see how it can be avoided under the statutory requirements.; Sincerely, Andrew G. Detrick, Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam1899OpenD. R. Bernard, Esq., Messrs. Bernard & Bernard, 4100 One Shell Plaza, Houston, TX 77002; D. R. Bernard Esq. Messrs. Bernard & Bernard 4100 One Shell Plaza Houston TX 77002; Dear Mr. Bernard: This is in reply to your letter of April 21, 1975, asking whethe certain 'safety lights' would violate the National Traffic and Motor Vehicle Safety Act of 1966.; As you describe it, your client's device flashes two lights at the rea of a motorcycle when brakes are applied. These lights are supplemental 'to the normal brake lights and turn signal lights.'; Paragraph S4.1.3 of 49 CFR 571.108, Motor Vehicle Safety Standard No 108, *Lamps, Reflective Devices, and Associated Equipment*, prohibits the installation of additional lighting equipment 'that impairs the effectiveness of lighting equipment' required by Standard No. 108.; Without knowing the size and photometric output of the lights, thei color and location, and whether they 'flash' in operation or are steady burning, we are unable to offer an opinion whether they are prohibited by paragraph S4.1.3. We would be happy to provide you with our views if you care to describe this system more fully.; 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.