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: aiam2304OpenHonorable James L. Buckley, United States Senate, Washington, DC 20510; Honorable James L. Buckley United States Senate Washington DC 20510; Dear Senator Buckley: This is in response to your letter of May 11, 1976, forwarding petition from Gulf + Western Manufacturing Company for reconsideration of the bumper standard recently issued as Part 581 of Title 49 Code of Federal Regulations.; A number of requests for our view on the Gulf + Western petition hav been forwarded by members of Congress who have received copies of the Gulf + Western petition accompanied by a letter from Mr. James A. Graham.; It is the National Highway Traffic Safety Administration's policy t issue a notice of action taken on petitions for reconsideration within 120 days after publication of the final rule, unless action within that time is impracticable. Since the agency is currently in the process of considering the petitions received, it would not be appropriate for us to comment at this time on the remarks made by Gulf + Western.; I assure you that Gulf + Western's comments and the informatio contained in all of the petitions for reconsideration will receive thorough consideration. The agency's response to the petitions will be published in the *Federal Register*.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2342OpenHonorable Guy Vander Jagt, House of Representatives, Washington, DC 20515; Honorable Guy Vander Jagt House of Representatives Washington DC 20515; Dear Mr. Vander Jagt: This is in response to your letter of June 14, 1976, forwarding petition from Gulf + Western Manufacturing Company for reconsideration of the bumper standard recently issued as Part 581 of Title 49 Code of Federal Regulations.; A number of requests for our view on the Gulf + Western petition hav been forwarded by members of Congress who have received copies of the Gulf + Western petition accompanied by a letter from Mr. James A. Graham.; It is the National Highway Traffic Safety Administration's policy t issue a notice of action taken on petitions for reconsideration within 120 days after publication of the final rule, unless action within that time is impracticable. Since the agency is currently in the process of considering the petitions received, it would not be appropriate for us to comment at this time on the remarks made by Gulf + Western.; I assure you that Gulf + Western's comments and the informatio contained in all of the petitions for reconsideration will receive thorough consideration. The agency's response to the petitions will be published in the *Federal Register*.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2487OpenMr. John F. McCuen, Kelsey-Hayes Company, Romulus, MI 48174; Mr. John F. McCuen Kelsey-Hayes Company Romulus MI 48174; Dear Mr. McCuen: This responds to Kelsey-Hayes Company's November 29, 1976, questio whether an antilock valve (incorporating the function of a relay valve) is subject to the requirement of S5.7.1 of Standard No. 121, *Air Brake Systems*, that a truck or bus be capable of stopping within a specified distance following failure in the service brake system of a part designed to contain compressed air or brake fluid (with the exception of certain parts that are common to both sides of a 'split' service brake system).; From your description, the antilock valve in question, whether or no it incorporates the function of a relay valve, is a part of the service brake system designed to contain compressed air, and would be one of the components whose failure would be subject to the requirement of S5.7.1. I assume that the valve would be in the subsystem to the front axle or to the rear axles of a truck or bus and, as such, would not be a valve that is common to both sides of a 'split' service brake system.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam1795OpenMr. William H. Toller, Manager Customer Service, MacDermid Incorporated, 526 Huntingdon Avenue, Waterbury, CT 06720; Mr. William H. Toller Manager Customer Service MacDermid Incorporated 526 Huntingdon Avenue Waterbury CT 06720; Dear Mr. Toller: This is in response to your letter of January 22, 1975, commenting o the recent proposal by the National Highway Traffic Safety Administration (NHTSA) to reduce the performance requirements for motor vehicle bumpers.; Under current Federal requirements, a vehicle bumper must be capable o withstanding 5-mph longitudinal front and rear barrier and pendulum impacts without experiencing certain types of specified damage. A recent NHTSA study, however, indicated that due to inflation, increasing shortages of certain materials, and the weight and cost of current production bumpers, the costs imposed by implementation of the bumper standard may be exceeding the benefits to be derived therefrom.; The proposed reduction in the requirements to 2 1/2 mph front and rea barrier and pendulum impacts was viewed as a means of attaining a favorable cost-benefit ratio by permitting the removal of certain heavy bumper system components. Considerable interest has been manifested in the contents of the proposal. The NHTSA conducted a public hearing on February 18 and 19, 1975, in order to permit the presentation of views from all interested persons regarding the proposed revision of the bumper standard.; The comment period for the notice has been extended until March 3 1975, in order to allow additional time for submission of comments and enable a full review of all evidence presented.; The comments contained in your letter will be placed in the appropriat public docket and will be considered in the formulation of the final rule.; Yours truly, James C. Schultz, Acting Chief Counsel |
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ID: aiam3333OpenMr. Kenneth D. Uding, Project Manager, Amerace Brands Division, Amerace Corporation, 1201 Mark Street, Elk Grove Village, Illinios(sic) 60007; Mr. Kenneth D. Uding Project Manager Amerace Brands Division Amerace Corporation 1201 Mark Street Elk Grove Village Illinios(sic) 60007; Dear Mr. Uding: This responds to your July 15, 1980, letter asking whether Standard No 125, *Warning Devices*, permits the manufacture of a device that must be assembled by the user prior to use. The device that you describe would require its base to be attached to a triangular section by the use of a threaded stud and a wing nut.; Standard No. 125 states in section S5.1.3 that '[t]he warning devic shall be designed to be erected, and replaced in its container, without the use if tools.' This statement implies that some manual operation to erect a warning device is permissible as long as the assembly does not require the use of any tools. For the device that you mention, it would appear that its two section would be coupled together by the use of a wing nut which would be tightened manually without the use of tools. If this description of your device is accurate, it is permissible to produce a warning device in this manner.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3491Open*AIR MAIL*, Mr. John Osborne, Rolls-Royce Motors, Limited Car Division, Crewe Cheshire, CW1 3PL, England; *AIR MAIL* Mr. John Osborne Rolls-Royce Motors Limited Car Division Crewe Cheshire CW1 3PL England; Dear Mr. Osborne: This is in response to your recent letter to the Administrator regarding Federal Motor Vehicle Safety Standard (FMVSS) No. 208, Occupant Crash Protection, and its related requirements for the comfort and convenience of safety belts.; You stated in reference to paragraph S7.4.4, Latchplate Access, tha *the standard as written is design restrictive in not permitting inboard location of the latchplate when stowed by virtue of requiring the latchplate to be located within the outboard reach envelope...* You requested that the wording be changed to permit either inboard or outboard reach envelopes.; Paragraph S7.4.4 was not intended to limit the location of latchplate to outboard locations. Latchplates located in the outboard reach must be located within the reach envelopes as specified. However, the requirement would not be applicable to latchplates located inboard, since there should be no difficulty in reaching latchplates in this location. It should also be noted that the requirement is not applicable to automatic belts.; We believe the Agency's response to the petitions for reconsideratio of the comfort and convenience requirements will answer your remaining questions. We expect to issue that notice in the very near future.; You requested an early announcement of the final content of FMVSS No 208 as it would apply to automatic restraints. On October 23, 1981, the Department rescinded that portion of the standard that would require automatic restraints. We have enclosed a copy of the news release pertaining to that action for your information.; Please contact this office if you have further questions. Sincerely, Michael M. Finkelstein, Associate Administrator fo Rulemaking; |
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ID: aiam0992OpenMr. John F. McCuen, Kelsey-Hayes Company, Romulus, MI 48174; Mr. John F. McCuen Kelsey-Hayes Company Romulus MI 48174; Dear Mr. McCuen: This is in reply to your letters of October 23, 1972 and January 25 1973, concerning the intent of the antilock performance requirements of Motor Vehicle Safety Standard No. 121. I apologize for our delay.; Your question arises from an amendment to S5.3.1 of the standard. A originally adopted in February 1971, the section required that the vehicle be capable of stopping without wheel lockup except for 'momentary' lockup allowed by an antilock system. As amended in February 1972, the word 'controlled' is used in place of 'momentary', so that the section now provides that stops are made; >>>without lockup of any wheel at speeds above 10 m.p.h. except fo controlled lockup of wheels allowed by an antilock system . . . .<<<; In making this change, the agency had in mind the type of antiloc system that was designed to permit one wheel on an axle to lock under some circumstance while the other wheels continued to turn. It was thought that adequate control could be attained by such systems, and the standard was amended accordingly.; The question you raise is whether a system could be designed in whic all wheels could be permitted to lock for substantial periods, so long as they are 'controlled' by an antilock system. As you correctly indicate, the term 'controlled', unlike 'momentary', is not a time-related word. Our answer, therefore, is that such an antilock system would be permitted under the standard as it now stands.; It is our present opinion, however, that such a system would probabl not provide an acceptable level of performance. If it appears that such a system would be installed, it is likely that we would undertake rulemaking action to prohibit it.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2831OpenMr. Don M. Carnahan, Supervisor, Pupil Transportation, Division of Financial Services, Office of Superintendent of Public Instruction, Old Capital Building, Olympia, WA 98504; Mr. Don M. Carnahan Supervisor Pupil Transportation Division of Financial Services Office of Superintendent of Public Instruction Old Capital Building Olympia WA 98504; Dear Mr. Carnahan: This is in reply to your letter of March 9, 1978, asking whether school bus manufacturer may install strobe lights on the top of vehicles as original equipment, without violating Federal Motor Vehicle Safety Standard No. 108. As you indicated in your letter of December 28, 1977, this would be permissible under local law.; I informed you on February 14, 1978, in requesting a clarification that legality depended on whether the additional lighting impaired the effectiveness of the required equipment. If so, paragraph S4.1.3 of Standard No. 108 would prohibit installation. The lamps in question are strobe lights, either white or amber in color, that would be used during inclement weather. We do not know whether these lights would be used while the bus is in motion, or when it is stopped and the required schoolbus warning lamps are activated. If the strobe lights are used while the vehicle is in motion, during inclement weather, we do not know whether they would impair the effectiveness of the stop lamps by distracting the attention of a driver following the bus. If the light of the strobe lamp is white, and the light operates while the vehicle is at rest and its red or red and amber warning signals are also activated, the signals might prove confusing to other motorists. However, on the basis of the data presented, it is not possible to determine whether the strobe lamps would impair the effectiveness of the required lighting equipment within the meaning of S4.1.3. Therefore, we are willing to defer to the judgment of the State of Washington on this question, until such time, if ever, as data may be presented supporting a conclusion of impairment.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0692OpenMr. O. L. Pierson, Legal Department, Rohm and Haas Company, Independence Mall West, Philadelphia, PA, 19105; Mr. O. L. Pierson Legal Department Rohm and Haas Company Independence Mall West Philadelphia PA 19105; Dear Mr. Pierson: This is in reply to your letter of April 17, 1972, in which you as certain questions regarding Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' the proposed amendment to that standard (36 F.R. 9565, May 26, 1971), and future requirements for labeling of safety glazing. Your questions are restated below, followed in each case by our response.; >>>1. We have heard that clarifying amendments for MVSS 302 are bein prepared and may be promulgated soon. Can you tell us approximately when such information may be published?; An amendment to Standard No. 302, based upon the notice of May 26 1971, and other information that has been presented to the agency is currently in preparation, and we expect its issuance within the next several weeks.; 2. We are concerned about 1973 requirements for labeling of safet glazing. Will your identification requirements prevail over state regulations which require additional and/or different information?; The National Traffic and Motor Vehicle Safety Act provides that Federa motor vehicle safety standards preempt State requirements to the extent that those requirements differ from the Federal standard regarding the same aspect of performance. We cannot determine whether specific State labeling requirements would be preempted by present or future Federal requirements without knowing specifically what the State requirements might be.; 3. If an exception is made in Standard No. 302 for small plastic parts would that exception include light-transmitting parts such as clock dials and instrument dials.; Paragraph S4.1 of Standard No. 302, in enumerating those motor vehicl components which must meet the standard's requirements, does not list either of the components you mention. Accordingly, they are not subject to the standard unless they are 'designed to absorb energy on contact by occupants in the event of a crash,' which appears to be unlikely.<<<; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4916OpenMr. Michael D. Incorvaia Manufacturing Engineering Manager Wagner Lighting P.O. Box 4650 Sevierville, TN 37864; Mr. Michael D. Incorvaia Manufacturing Engineering Manager Wagner Lighting P.O. Box 4650 Sevierville TN 37864; Dear Mr. Incorvaia: This responds further to your letter of July 3 1991, which we informed you on August 20, will be accorded confidential treatment. Paragraph 4.5 of SAE Standard J588e, Turn Signal Lamps, September 1970, states that 'failure of one or more turn signal lamps to operate should be indicated by a 'steady on', 'steady off', or by a significant change in the flashing rate of the illuminated indicator.' Electronic flashers available today provide a 'significant change' in flash rate by doubling it as an outage indication. Wagner Lighting has developed a lamp outage indication that will remain within the performance parameters of Standard No. 108, but provide an outage flash rate that appears to be slightly less than 50% greater than that of normal operation. However, there will be 'a recognized change in flashing rate.' You have asked whether these changes may be regarded as 'significant' within the meaning of SAE J588e. Your letter indicates that the design contemplated by Wagner Electric is for application in new motor vehicles. Although SAE J588e remains in effect as a replacement equipment standard, Standard No. 108 has been amended to incorporate by reference new SAE standards for turn signal lamps, and it is these standards that now apply to turn signals on new motor vehicles. Specifically, on and after December 1, l990, a motor vehicle must be manufactured to meet either SAE Standard J588 NOV84, Turn Signal Lamps for Use on Motor Vehicles Less Than 2032 mm in Overall Width, or SAE Standard J1395 APR85, Turn Signal Lamps for Use on Motor Vehicles 2032 mm or More in Overall Width. The outage indication requirement of SAE J588e was not adopted in either of the SAE standards, and has not been incorporated directly in Standard No. 108. This means that outage indication is no longer a requirement on new motor vehicles, and that Wagner Electric, under Standard No. 108, may adopt such change in flash rate as its design may call for. We are returning the tape that you enclosed. Sincerely, Paul Jackson Rice Chief Counsel Enclosure; |
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.