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: nht88-2.48OpenTYPE: INTERPRETATION-NHTSA DATE: 06/10/88 FROM: T. BAILEY -- LEGISLATION ENGINEER, INTERNATIONAL AUTOMOTIVE DESIGN TO: NHTSA TITLE: FMVSS 104 Windshield WIPING & WASHING SYTEMS ATTACHMT: MEMO DATED 11-3-88, TO T.P. BAILEY, FROM ERIKA Z. JONES, STD. 104 TEXT: As an automotive design consultancy we need a clear understanding of this Standard, particularly the requirements of paragraph S4.1.2, Wiped Area. We have a problem with this and would appreciate some advice. Firstly, can you confirm this paragraph is only applicable to passenger cars. Secondly, the hypothetical results for a windscreen are shown on attachment 1. In this, Area A on one side extends to the DLO, on the other, overlaps it. (The DLO is taken to start at the inner edge of the obscuration band). As drawn, the correct perce ntage wiped area is still achieved. Should Area A be wholly:- 1. On exterior surface of glass, inside a perimeter line drawn one inch from edge of daylight opening. 2. On exterior surface of glass, inside the DLO. 3. On exterior surface of glass (ie. whole surface visible from outside vehicle including the obscuration band). 4. On total exterior surface of glass (ie. including the part normally hidden under trim and mouldings). Thank you for your attention. I look forward to hearing from you. See Illumtation on original |
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ID: 1982-2.20OpenDATE: 07/21/82 FROM: Frank Berndt; NHTSA TO: Arnold P. Fuchs TITLE: FMVSS INTERPRETATION TEXT: This letter is to confirm your view, expressed in a telephone call with Edward Glancy of this office, that the requirements of Standard No. 206, Door Locks and Door Retention Components, are not applicable to a replacement latch for a truck built in l969. The requirements of Standard No. 206 are applicable to passenger cars, multipurpose passenger vehicles and trucks. See S2 of that Standard. However, its requirements are not applicable to replacement parts for installation in used vehicles of these types. Further, the "render inoperative" provisions of the National Traffic and Motor Vehicle Safety Act are not relevant to the installation of such a latch. Under section 108(a)(2)(A) of that Act, a business such as a garage must make sure that it does not knowingly render inoperative the compliance of a vehicle with any applicable safety standard. With respect to a 1969 truck and Standard No. 206, there is no compliance which could be rendered inoperative since the Standard was never applicable to that truck. That Standard applies only to trucks manufactured on or after January 1, 1972. I would note that even in the absence of an applicable safety standard, the defect provisions of the Act may be applicable. Sections 151 et seq. of the Act provide that manufacturers of motor vehicles and motor vehicle equipment must notify owners of vehicles and equipment with safety-related defects and remedy those defects free of charge. |
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ID: 1985-02.46OpenTYPE: INTERPRETATION-NHTSA DATE: 06/24/85 FROM: AUTHOR UNAVAILABLE; Jeffrey R. Miller; NHTSA TO: Dick Kruse -- Secondary School Principals Association TITLE: FMVSS INTERPRETATION TEXT:
Mr. Dick Kruse Secondary School Principals Association 1904 Association Drive Reston, Virginia 22091
This responds to your May 30, 1985 telephone call to this office asking two related questions about our school bus regulations. Your first question asked whether the National Traffic and Motor Vehicle Safety Act prohibits the sale of a used commercial-type bus to a school district for use on school-related events. The answer to your question is no. The Act only applies to the manufacture and sale of new motor vehicles and new motor vehicle equipment. Persons selling a used bus to a school district are not subject to the Act's requirement to sell certified school buses, and a used commercial-type bus, regardless of its model year, may be sold as an activity bus.
Your second question asked whether section 108(a)(1)(A) of the Vehicle Safety Act is applicable to manufacturers and dealers who sell used commercial-type buses to school districts. The answer is no. Section 108(a)(1)(A) prohibits the manufacture and sale of any new motor vehicle or item of motor vehicle equipment that does not conform to applicable motor vehicle safety standards. Therefore, there would be no Federal penalty upon a person selling a used commercial-type bus for school use.
Sincerely, Jeffrey R. Miller Chief Counsel |
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ID: nht87-2.34OpenTYPE: INTERPRETATION-NHTSA DATE: 07/09/87 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: Mr. David O. Johnson TITLE: FMVSS INTERPRETATION TEXT: Mr. David O. Johnson 135 Karen Drive Washington, PA 15301 Dear Mr. Johnson: This responds to your April 22, 1987, letter asking about the legality of transporting people in fifth wheel trailers. The National Highway Traffic Safety Administration is responsible for promulgating safety standards for the manufacture and sale of new motor vehicles. The use of a motor vehicle, such as a trailer, is a matter over which we have no jurisdiction. Because the legality of carrying people in trailers might be governed by State law, we suggest you contact State officials with your questions. Additionally, questions you might have about the operation of interstate motor carriers should be directed to Mr. Ton Kozlowski of the Office of Motor Carrier Standards (Room 3403 ), Federal Highway Administration, at this address. Sincerely, Erika Z. Jones Chief Counsel 135 Karen Drive Washington, PA 15301 April 22, 1987 Gentlemen: Please send any information concerning regulations governing the legality of transporting people in a fifth wheel trailer with an intercom between the travel trailer and the towing vehicle. My understanding is that the Navy transports personnel in this manner which leads me to believe it is legal to do so. Your prompt attention will be appreciated. Sincerely, David O. Johnson |
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ID: nht89-1.53OpenTYPE: INTERPRETATION-NHTSA DATE: 03/27/89 FROM: SHUICHI WATANABE -- MANAGER, AUTOMOTIVE LIGHTING HOMOLOGATION SECT. STANLEY ELECTRIC CO, JAPAN TO: ERIKA Z. JONES -- CHIEF COUNSEL DEPARTMENT OF TRANSPORTATION NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: MEASUREMENT OF INCIDENT LIGHT ANGLE ATTACHMT: ATTACHED TO LETTER FROM STEPHEN P. WOOD OF NHTSA TO SHUICHI WATANABE OF STANLEY ELECTRIC CO OF JAPAN; REDBOOK A34, STANDARD 108 TEXT: Dear Ms. Jones, According to SAE J587 Oct 81 6.5 and Fig. 3 which is quoted by present FMVSS No. 108, it says, This angle being measured from the edge of the light emitting surface of the device farthest from the surface of the plate. In order to determine the farthest point on the light emitting surface, we understand that only the distance "1" between license plate and a plane runs parallel to it should be considered and not by distance "m" nor "n". (See Fig. A of attached paper.) This also means that in the case of round and dome shaped license plate light (Fig. B), you will easily find only one point "p" as the farthest point. But if the farthest point can exist so may on a line or a plane as described in Fig. C or D, how could it be determined? Should it be for instance, left end, right end or center of them? We also have same question for E and F. It will be very much appreciated if you could give us a clear discrimination. Yours faithfully, ATTCH: [ATTACHED DIAGRAM OMITTED] |
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ID: nht76-1.36OpenDATE: 02/26/76 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: E.T.R.T.O. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of January 26, 1976, which inquired about the status of the E.T.R.T.O. petition for an amendment of Federal Motor Vehicle Safety Standard No. 119, New Pneumatic Tires for Vehicles Other Than Passenger Cars, concerning tires for low-power motorcycles with restricted speed capability. We expect to issue a Federal Register notice on this subject in the near future. Yours truly, ATTACH. The Director -- National Highway Traffic Safety Administration, U.S. Department of Transportation JANUARY 26, 1976 ETRTO SUBMISSION No. 6/119 TYRES FOR LOW-POWER MOTORCYCLES WITH RESTRICTED SPEED CAPABILITY Dear Sir, The above Submission was made in ETRTO letter ref. RD/MS 048/75 dated February 5, 1975 and in a letter dated March 4, 1975, ref. N40-30 MS, signed by Mr. R.B. DYSON, Assistant Chief Counsel, receipt of the Submission was acknowledged with the advice that it was under consideration. Since then, as far as is known, there has been no further communication from NHTSA and no notice referring to the Submission has appeared in the Federal Register. News of the current status of this Submission would be greatly appreciated. Yours faithfully, J. TRIMBLE Secretary General cc: R.P. Monier, Chairman of the ETRTO Road Safety Sub-Committee. |
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ID: nht76-2.4OpenDATE: 02/25/76 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: General Motors Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of February 10, 1976, concerning the definition of "daylight opening" (DLO) as specified in Motor Vehicle Safety Standard No. 219, Windshield Zone Intrusion, 49 CFR 571.219, and concerning the procedure used by General Motors to determine DLO. Your letter states that General Motors is concerned about the definition of DLO as stated in Standard No. 219, and "believes that the wording is not easily understood." The definition of DLO as stated in the Standard is based upon the definition found in paragraph 2.3.12 of Section E, Ground Vehicle Practice, SAE Areospace Automotive Drawing Standards, September, 1963. The SAE definition was slightly modified to reflect the particular characteristics of Standard No. 219. The last phrase of the SAE definition was changed to read "as measured parallel to the outer surface of the glazing material," because there was concern that there might be some confusion if the definition directed measurement by means of a "vertical projection". Your letter describes General Motors' procedure for obtaining DLO, and asks if this procedure is consistent with the definition of DLO as specified in Standard No. 219. The answer to your question is yes. Your illustration (Figure 1) shows that you are measuring "parallel to the outer surface of the glazing material". Your Figure 1 is a simplified illustration, of course, since nearly all windshields are curved. Please contact us if we can be of any further assistance. |
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ID: nht90-3.55OpenTYPE: Interpretation-NHTSA DATE: August 14, 1990 FROM: Gerald F. Vinci -- Sun Refining and Marketing Company TO: Paul Jackson Rice -- Office of the Chief Counsel, NHTSA TITLE: None ATTACHMT: Attached to letter dated 9-17-90 from P.J. Rice to G.F. Vinci (A36; FMVSS 301; VSA 108(b)(1)); Also attached to letter dated 8-17-79 from F. Berndt (Signature by S.P. Wood) to M. Champagne TEXT: Our research and development department at Sun Refining and Marketing Company is interested in converting the fuel system of a new vehicle from gasoline to propane. Sun does not intend to act as a manufacturer. The only portion of the vehicle which wil l be substantially altered is the fuel system. The vehicle is intended to be driven under normal traffic conditions and would maintain a lower emission level than that required under the Clean Air Act. I spoke recently with Dee Fujita and Taylor Vinson of the Chief Counsel's Office. After factually reviewing the project, both concluded that such a vehicle would not violate the National Traffic and Motor Vehicle Safety Act and its regulations. Ms. Fuj ita and Mr. Vinson did however caution that there may be requirements under state law. We recognize the importance of highway safety and intend to fully comply with all applicable federal laws. To assist us, I respectfully request an opinion letter addressing compliance of such a vehicle with the Act and its regulations. If you need any additional information, please contact me at (215)246-8251. |
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ID: nht88-3.29OpenTYPE: INTERPRETATION-NHTSA DATE: 08/30/88 FROM: SPENCER A. DORBY -- SATE-LITE MFG. CO. TO: JOAN TILGHMAN - NHTSA TITLE: 2166 ATTACHMT: ATTACHED TO LETTER DATED 11/07/88 FROM ERIKA Z JONES TO SPENCER A DARBY, REDBOOK A32, STANDARD 125; LETTER DATED 05/19/88 FROM SPENCER A DARBY TO JOAN TILGHMAN RE REQUEST FOR INTERPRETATION OF FMVSS 1255, OCC-2166 TEXT: Dear Ms. Tilgham: Attached is the drawing we referred to this AM on the phone, showing the recommended diagrams to help insure that Warning Device user will know how to erect the Emergency Warning Triangle properly. As Chairman of the SAE Reflex Devices Subcommittee, I will be including these diagrams (or similar versions) in an updated version of SAE 774, a Recommended Practice document of the Society of Automotive Engineers, in the next approval process due thi s year. Please call if I can be of any further assistance. ON ANY TYPE HIGHWAY VEHICLE USING 1 TRIANGLE Figure 3. ON A NON-DIVIDED HIGHWAY TRUCK USING 3 TRIANGLES Figure 4. ON A DIVIDED HIGHWAY TRUCK USING 3 TRIANGLES Figure 5. RECOMMENDED DIAGRAMS TO BE "PERMANENTLY AND LEGIBLY MARKED" ON THE WARNING DEVICE, AND ALSO ON THE "OPAQUE PROTECTIVE REUSABLE CONTAINER". Sate-lite MFG. CO. CAD TITLE 125 DIAGRAMS TRIA-DIA Drawing Number 880830 |
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ID: nht89-2.64OpenTYPE: INTERPRETATION-NHTSA DATE: 08/09/89 FROM: KARL HEINZFABER -- MERCEDES BENZ OF NORTH AMERICA INC TO: STEPHEN P. WOOD -- ACTING CHIEF COUNSEL OFFICE OF CHIEF COUNSEL NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: REQUEST FOR INTERPRETATION, FMVSS 108, LAMPS, REFLECTIVE DEVICES AND ASSOCIATED EQUIPMENT ATTACHMT: ATTACHED TO LETTER DATED 11/01/89 FROM STEPHEN P. WOOD -- NHTSA TO KARLHEINZ FABER -- MERCEDES BENZ OF NORTH AMERICA; REDBOOK A34; STANDARD 108 TEXT: Dear Mr. Wood: Mercedes-Benz of North America, Inc. (MBNA) requests an interpretation of the word "headlamp" as used in Standard 108. Paragraph S7.2 of the Final Rule published in the Federal Register of May 9, 1989 (Docket No. 85-15, Notice 8), states that each headlamp or beam contributor must be marked with its voltage. The term headlamp is not defined separately under S4 definitio ns, however, a "replaceable bulb headlamp" is defined as a "headlamp comprising a bonded lens and reflector assembly and one or two standardized replaceable light sources." Based on the definition of "replaceable bulb headlamp", it is our understanding t hat marking the lens, the reflector, or the light source with the voltage would be in compliance with paragraph S7.2. We would appreciate your response at your earliest opportunity as the effective date of this marking requirement is December 1, 1989. Should you have any additional questions, please feel free to contact Toivo Raabis at (201) 573-2624 in our Safety Engineering Department. Thank you in advance for your reply. Sincerely, |
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.