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 |
|---|---|
ID: aiam1895OpenMr. Donald W. Segraves, Vice President, American Mutual Insurance Alliance, 20 North Wacker Drive, Chicago, IL 60606; Mr. Donald W. Segraves Vice President American Mutual Insurance Alliance 20 North Wacker Drive Chicago IL 60606; Dear Mr. Segraves: This is in response to your letter of March 19, 1975, requestin additional information on two aspects of the March 12, 1975, Federal Register notice (40 FR 11598) proposing to amend the Federal bumper standard.; Your first question relates to the proposed reduction in the number o required longitudinal pendulum impacts from 6 to 2, front and rear. According to a Transportation Systems Center report dated July 1974, an average car is involved in 4.7 low speed (5 mph or below) accidents in its 10-year or 100,000-mile lifetime. Of these, 1.25 are insurance reported, 33% of which are front or rear collisions, 1.25 are repaired but not insurance reported, 62% of which are front or rear collisions, and 2.20 are unrepaired, 38% of which are front or rear collisions. The conclusion reached in the report is that a vehicle is involved in 2.03 front or rear low-speed collisions in its lifetime.; The NHTSA has no specific information regarding reduction in weight an cost of vehicles due to the lowering of the number of pendulum impacts.; Responding to your second question, the NHTSA has not determined wha the cost-benefit trade-off would be in permitting damage to the bumper face bar components and associated fasteners. The decision to allow such damage until 1979 was based on a determination that some manufacturers needed that amount of lead time in order to produce vehicles capable of meeting the more stringent damage criteria. The proposed schedule for implementation of the surface damage criteria would not effect a lowering of the current level of bumper performance and would permit adequate time for the development of more durable bumper systems.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam0787OpenMr. Louis C. Lundstrom, Director, Automotive Safety Engineering, General Motors Corporation, General Motors Technical Center, Warren, MI, 48090; Mr. Louis C. Lundstrom Director Automotive Safety Engineering General Motors Corporation General Motors Technical Center Warren MI 48090; Dear Mr. Lundstrom: This is in reply to your letter of July 17, 1972, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' to radio speaker cones. You request clarification of an interpretation we sent to American Motors dated June 9, 1972, wherein we stated that 'stereo speaker . . . cones incorporated into a door or rear shelf would be considered part of a 'trim panel' and 'compartment shelf,' respectively.' You particularly request clarification of the phrase 'incorporated into.'; The NHTSA's position is that a speaker cone, while not generall subject to Standard No. 302 (we assume that it is not an 'energy-absorbing' component), will be subject to the standard if it is 'incorporated into' a component that is subject to the standard. We would consider a speaker cone to be 'incorporated into' a trim panel or compartment shelf if the cone forms a portion of the surface of the panel or shelf. We would not consider a speaker cone merely attached to an enumerated component, but situated wholly underneath (shelf) or behind (trim panel) its surface to be subject to the standard.; I trust this clarifies our position. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3902OpenMr. T. Chikada, Manager, Automotive Lighting, Engineering Control Dept., Stanley Electric Co., Ltd., 2-9-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. T. Chikada Manager Automotive Lighting Engineering Control Dept. Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Chikada: This is in reply to your letter of January 18, 1985, to Mr. Vinson o this office asking for three interpretations of Motor Vehicle Safety Standard No. 108 with respect to motorcycle lighting.; Your first question is about the location of rear turn signals. Tabl IV of Standard No. 108 requires that rear turn signal lamps on motorcycles have a minimum horizontal separation distance 'centerline to centerline' of 9 inches. You have asked whether this may be interpreted as filament center to filament center., The answer is no. The phrase means the distance from the geometric center of one lamp to the geometric center of the other.; Your second questions concerns the permissibility of an arrangement o lamps on the rear of a motorcycle. There would be a two-compartment combination stop/tail lamp on the vehicle centerline with separate combination lamps below it on either side of the centerline. The distance between filament centers of the separate lamps would be a maximum 16 inches, and there would be the same distance between the filament centers of each separate lamp and the compartment above it belonging to the two- compartment lamp. You have asked whether this is permissible if the minimum design candlepower complies with requirements for three lighted sections in SAE J585e and SAE J586c, and the effective projected luminous lens area of each compartment or lamp is at least 3 1/2 square inches. This arrangement, though unusual, appears to be acceptable. SAE Standard J586c *Stop Lamps* and SAE J585e *Tail Lamps* state that if multiple compartment or multiple lamps are used, and the distance between filament centers does not exceed 16 inches for three compartment or lamp arrangements, the combination of the compartments or lamps must be used to meet the photometric requirements for the corresponding number of lighted sections. Your design has four lighted sections, where as the SAE Tables provide values for only three. In our opinion, your design would be acceptable provided that each of the four compartments meets the minimum value specified for test points in a section when there are three lighted sections.; Your final question concerns a combination stop/taillamp of fou sections, two each on either side of the vertical centerline. Though no distance is given for the filament centers, they appear to be closer than 16 inches. You have asked if this design is permissible provided it meets the requirements for three lighted sections, and the effective projected luminous lens area of each compartment is not less than 3 1/2 square inches. The answer is yes, this is acceptable provided that each of the four compartments meets the minimum value specified for test points in a section when there are three lighted sections.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2610OpenMr. James M. Beach, Director of Engineering, Collins Industries, Inc., P. O. Box 58, Hutchinson, KS 67501; Mr. James M. Beach Director of Engineering Collins Industries Inc. P. O. Box 58 Hutchinson KS 67501; Dear Mr. Beach: This responds to your May 6, 1977, question whether Safety Standard No 301-75, *Fuel System Integrity*, is applicable to all school buses or only to school buses with a GVWR greater than 10,000 pounds.; You are correct in your statement that school buses are included in th broader classification, 'buses', for purposes of the Federal motor vehicle safety standards, unless otherwise specified in a particular standard. Safety Standard No. 301-75 is applicable to passenger cars, and to multipurpose passenger vehicles, trucks and buses that have a GVWR of 10,000 pounds of less, including school buses under 10,000 pounds. The standard is also applicable to larger school buses, and the distinction is made in the standard since the large school buses are the only vehicles having a GVWR greater than 10,000 pounds that are covered by the standard.; Safety Standard No. 301-75 was made applicable to all school buse pursuant to a mandate under the Motor Vehicle and Schoolbus Safety Amendments of 1974 (15 U.S.C. 1392(i)(1)(A)).; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2305OpenHonorable William S. Broomfield, House of Representatives, Washington, DC 20515; Honorable William S. Broomfield House of Representatives Washington DC 20515; Dear Mr. Broomfield: This is in response to your letter of May 10, 1976, forwarding petition for reconsideration of the recently issued Part 581 bumper standard from Gulf + Western Manufacturing Company. You indicate your support of the petition and request that you be informed of any action taken by the agency concerning the bumper standard.; 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. I assure you that Gulf + Western's comments and the information 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*, a copy of which will be sent as requested.; Sincerely, James B. Gregory, Administrator |
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ID: aiam0338OpenCharles O. Verrill, Jr. Patton, Blow, Verrill, Brand & Boggs, 1200 Seventeenth Street, N.W., Washington, D.C. 20036; Charles O. Verrill Jr. Patton Blow Verrill Brand & Boggs 1200 Seventeenth Street N.W. Washington D.C. 20036; Dear Mr. Verrill: #This is in reply to your letter of May 3, 1971 requesting an additional interpretation of the Tire Identification and Record Keeping Regulation. #If in fact, the vehicle manufactured is not considered a motor vehicle within the meaning of the Act and the mini-bike interpretation (34 F.R. 15416)(copy enclosed), then Part 574, the Tire Identification and Record Keeping Regulation, and section 113 (15 U.S.C. 1402) will be inapplicable. #Sincerely, Lawrence R. Schneider, Acting Chief Counsel; |
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ID: aiam0292OpenMr. Harold Vischer, Vice President, Bandag, Incorporated, 1056 Hershey Avenue, Muscatine, IA 52761; Mr. Harold Vischer Vice President Bandag Incorporated 1056 Hershey Avenue Muscatine IA 52761; Dear Mr. Vischer: This is in reply to your letter to Mr. Hartman concerning the tir identification and record keeping regulation (49 CFR Part 574) requesting that you be allowed to code by pressure chamber rather than by matrix.; Since the pressure chamber is used by Bandag to serve a purpose simila to the purpose served by the matrix in hot processing of retreaded tires, you may assign code numbers to your pressure chambers and use this code number in place of the matrix code number required by Part 574.; Sincerely, Rodolfo A. Diaz, Acting Associate Administrator, Moto Vehicle Programs; |
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ID: aiam3847OpenMr. C. I. Nielsen III, Vice President - Marketing, Wesbar Corporation, Box 577, West Bend, WI 53095; Mr. C. I. Nielsen III Vice President - Marketing Wesbar Corporation Box 577 West Bend WI 53095; Dear Mr. Nielsen: This is in reply to your letter of May 16, 1984, to Mr. Vinson of thi office seeking an interpretation of Motor Vehicle Safety Standard No. 108. You wish to know whether the minimum effective projected luminous lens area for stop lamps and turn signal lamps on trailers whose overall width is 80 inches or greater is 8 square inches or 12 square inches. You cite an apparent conflict between paragraph S4.1.1.6 and SAE Standard J586d, and paragraph S4.1.1.7 and SAE Standard J588f. You have asked for an interpretation so that Wesbar may properly design a 'combination tail lamp.'; First, we will confirm the advice provided by 'D.O.T. staff people that the latest SAE revisions, J586d and J588f, have not been adopted.; You do not state the intended use of your proposed lamp, so we wil assume that it will be sold to trailer manufacturers as original equipment, and to the aftermarket as replacement equipment. As original equipment, it must comply with the requirements specified in Table I of Standard No. 108, SAE J586c for stop lamps and SAE J588e for turn signal lamps. Paragraph 3.2 of each standard specifies a minimum effective projected luminous lens area of 8 square inches.; Paragraphs S4.1.1.6 and S4.1.1.7 become relevant, however, if Wesba intends the lamp as replacement equipment on trailers manufactured before September 1, 1978, and after January 1, 1972 (turn signal lamps) and January 1, 1973 (stop lamps). Under paragraphs S4.1.1.6 and S4.1.1.7, replacement stop and turn signal lamps for trailers manufactured within the 1972-1978 time frame may meet either J586b or J586c, and either J588d or J588e. We note that neither J586b nor paragraph S4.1.1.6 establish a minimum luminous lens area for stop lamps. However, a manufacturer who chooses to comply with paragraph S4.1.1.7 rather than J588e would have to provide the minimum specified luminous lens area of 12 square inches for turn signal lamps of trailers whose overall width was 80 inches or more, the requirement specified in J588d for Class A turn signal lamps. We view this interpretation as one of historical interest than (sic) current relevance.; In summary, if Wesbar designs its lamp to the 8-inch requirement, i would appear to meet specifications for application either as original or replacement equipment.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2755OpenMr. Harold A. Bullock, 1402 Redway Lane, Houston, Texas 77062; Mr. Harold A. Bullock 1402 Redway Lane Houston Texas 77062; Dear Mr. Bullock: This responds to your December 29, 1977, letter asking whether Standar No. 124, *Accelerator Control Systems*, applies to a cruise control device that you manufacture.; In Docket 69-20, Notice 3, to which you refer in your letter, th National Highway Traffic Safety Administration stated that Standard No. 124 contains no requirements for cruise controls. Therefore, the standard does not apply to them. There are no other safety standards applicable to these devices.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5090OpenMr. T. Kouchi Director & General Manager Automotive Equipment Development & Administration Dept. Stanley Electric Co. Ltd. 2-9-13, Nakameguro-ku, Meguro-ku Tokyo 153, Japan; Mr. T. Kouchi Director & General Manager Automotive Equipment Development & Administration Dept. Stanley Electric Co. Ltd. 2-9-13 Nakameguro-ku Meguro-ku Tokyo 153 Japan; "Dear Mr. Kouchi: This responds to your letter of October 8, 1992, wit respect to photometric test methods for a center high-mounted stop lamp using light emitting diodes (LEDs) as light sources. Your letter presents certain procedures and asks for associated revisions in Federal Motor Vehicle Safety Standard No. 108. After review, we have come to the conclusion that your method of proposed testing is allowable under Standard No. 108, but more stringent than what the standard requires. In the section of your letter called 'BACKGROUND', you state that you usually follow the technical guidance of SAE J1889 as a standard practice for LED lighting devices. There is no requirement in Standard No. 108 or in any of the SAE standards incorporated by reference in Standard No. 108 that requires you to follow the test methodology of J1889. Thus, when you say that you 'must always allow a margin of the same percentage when designing initial light output of the lamp, which necessitates increase in the number of LEDs used, lamp size, product cost, and, therefore, user's expense', you are placing a burden upon yourself that does exist under J1889, but one which is not necessary for designing for compliance with Standard No. 108. You have proposed a solution for the problem you have created by following J1889, and you provide three specific reasons in support. The third reason is based upon your interpretation of SAE J575's warpage test, under which you test operating cycles of 5 minutes on and 5 minutes off. However, you reference a version of J575 which does not apply to center high-mounted stop lamps. Paragraph S6.1 of Standard No. 108 specifies that J575e, August 1970, applies to high-mounted stop lamps designed to conform to SAE Recommended Practice J186a. SAE J575, August 1970, simply specifies that the device is to be operated in the test in the same manner as it will be operated in service, far different than the cycle method you employ. Thus, you have requested that we revise Standard No. 108 by adding a new provision that center high-mounted stop lamps shall be energized for a minimum of 5 minutes before measurement of photometric minima. We note that nothing prohibits you from testing in such a manner, but we believe that an amendment of this nature is not required because the present allowable method of testing does not call for it. You have asked for our comments on four steps of photometric measurement, and our permission to follow them. There is no reason you may not follow them, if you wish, but they are unnecessary to design for compliance under Standard No. 108. I hope that this is responsive to your questions. Sincerely, Paul Jackson Rice 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.