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: nht94-3.26OpenTYPE: INTERPRETATION-NHTSA DATE: June 8, 1994 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: S. Greiff -- PARS, Passive Ruckhaltesysteme GmbH TITLE: None ATTACHMT: Attached To Letter Dated 4/19/94 From S. Greiff To US Department of Transportation (OCC-9886) TEXT: Dear Mr. Greiff: This responds to your letter of April 19, 1994, requesting an interpretation of the 500 foot minimum runway length in the Laboratory Test Procedure for Federal motor vehicle safety standards Nos. 208, 212, 219, and 301. Laboratory Test Procedures are provided to contracted laboratories as guidelines for conducting compliance tests. The Laboratory Test Procedures do not limit the requirements of the applicable Federal motor vehicle safety standards. None of the standar ds referenced in your letter include any requirement for minimum runway length. Instead, the standards specify that the collision into the fixed barrier will occur at any speed up to and including 30 mph. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, |
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ID: nht89-2.80OpenTYPE: INTERPRETATION-NHTSA DATE: 08/24/89 FROM: SADATO KADOYA -- MAZDA RESEARCH AND DEVELOPMENT TO: STEPHEN WOOD -- ACTING CHIEF COUNSEL OFFICE OF CHIEF COUNSEL NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: REQUEST FOR INTERPRETATION - FMVSS 108: LAMPS, REFLECTIVE DEVICE, AND ASSOCIATED EQUIPMENT ATTACHMT: LETTER DATED 10/06/89 FROM STEPHEN P. WOOD OF NHTSA TO SADATO KADOYA OF MAZDA, REDBOOK A34, STANDARD 108 TEXT: Dear Mr. Wood: Mazda would like to ask for your advice and interpretation as to what is the correct interpretation on the location requirement of the highmounted stop lamp. S5.3.1.8 of FMVSS 108 specifies that no portion of the lens shall be lower than 3 inches below the rear window in case of a car other than convertibles if the lamp is mounted below the rear window. Mazda is looking for the exact allowable areas where the lamp lens may be mounted, and shown below are two possible interpretations as seen by Mazda. (TEXT OMITTED) SEE ILLUSTRATION IN ORIGINAL Mazda would be very appreciative if you would advice us which is a correct interpretation or exact allowable lens location, if neither of these is correct. Regards, |
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ID: 86-1.38OpenTYPE: INTERPRETATION-NHTSA DATE: 02/13/86 FROM: JOSEPH A. GIAMPAPA TO: ERIKA Z. JONES -- CHIEF COUNSEL NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 09/05/86 EST, TO JOSEPH A GIAMPAPA FROM ERIKA Z. JONES; REDBOOK A29; VSA 108 TEXT: Dear Ms. Jones: My telephone inquiry to the Office of the General Counsel (Joanne Petrie, Esq.) was referred to Steven Ash, Esq., of your staff. The inquiry concerned whether or not a product one of my clients intends to manufacture might be subject to federal regulation. The subject device is an Auto Body Gauge for use by auto body specialists when performing repairs, and is not equipment actually used inside a vehicle. A copy of the patent covering this item is enclosed herewith for explanatory purposes. I hereby request a formal opinion as to whether or not said device is subject to NHTSA regulations. I would also appreciate your passing on information about any other regulations you might know of which such a device might be subject to. Meanwhile, let me thank you, in advance, for your time and careful attention to this matter. If I can be of further assistance in this inquiry, please do not hesitate to contact me. ENCLOSURE OMITTED |
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ID: nht81-2.39OpenDATE: 06/25/81 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Japan Automobile Tire Manufacturers Association, Inc. TITLE: FMVSS INTERPRETATION TEXT: This responds to your recent request for an interpretation of the labeling requirements of Safety Standard No. 109 (49 CFR @ 571.109). Specifically, your association wants to know if Standard 109 permits tire manufacturers to include the letters "H," "S," or "V," as appropriate, in the tire size designation required to appear on the sidewall of passenger car tires by S4.3(a) of the Standard. Such labeling is permitted by Standard 109. The speed rating symbols ("H," "S," or "V") established by the European Tyre and Rim Technical Organization, indicate that a tire is an acceptable high-speed tire. This permits, for example, a knowledgeable purchaser of tires for emergency vehicles to know that these tires are suitable for the higher operational speeds necessary for those vehicles. Use of these symbols in the size designation would not likely confuse the less sophisticated consumer, or otherwise defeat the purpose of the labeling information. Accordingly, use of these symbols is permitted under Standard 109. If you have any further questions, or need further information on this matter, please feel free to contact Steve Kratzke of my staff (202-426-2992). |
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ID: nht94-1.86OpenTYPE: Interpretation-NHTSA DATE: March 17, 1994 FROM: Eric T. Stewart -- Engineering Manager, Mid Bus TO: Office of Chief Counsel, NHTSA TITLE: Reference: Amendment to FMVSS 571.217 published in the Federal Register November 11, 1992 (Docket 88-21 notice No. 3) ATTACHMT: Attached to letter dated 4/1/94 from John Womack to Eric T. Stewart (A42; Std. 217); Also attached to letter dated 7/7/93 from John Womack to Thomas D. Turner TEXT: The background to this amendment indicates that the "final rule requires a minimum of 1 inch wide retro-reflective tape ...." (page 49421). The actual amendment reads that the retro-reflective tape is to be "a minimum 3 centimeters wide". (page 49425) (CFR571.217 S 5.53(c)). These two dimensions are not the same since 1.00 inch is equal to 2.54 centimeters. I believe that the intent of this rule making was to make the retro-reflective tape 1.00 inch wide and an error has taken place in converting the dimension to metric units. I am requesting written clarification indicating how wide NHTSA wants the retro- reflective tape around the outside perimeter of a school bus emergency door. If you have any questions, please call me at (419) 221-2525. |
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ID: nht95-3.100OpenTYPE: INTERPRETATION-NHTSA DATE: August 28, 1995 FROM: Joseph J. Smith -- Assistant Chief Maintenance Officer, Technical Services & Maintenance Support, Department of Buses, New York Transit Authority TO: John Womack -- Office of Chief Counsel, NHTSA TITLE: NONE ATTACHMT: ATTACHED TO 9/29/95 LETTER FROM JOHN WOMACK TO JOSEPH J. SMITH (A43; STD. 302) TEXT: Dear Mr. Womack: I am requesting interpretation of NHTSA Standard No. 302; Flammability of interior materials (49 CFR Ch. V, 10-1-94 Edition, para. 571.302). The Department of Buses, MTA New York City Transit, has been notified by a supplier of air conditioning (A/C) return air filters that their filters do not meet Standard No. 302. The A/C filters that the DOB utilizes on RTS 04 and 06 model buses are located on the top of A/C evaporator coil. Although the A/C filters are not mentioned in para. S4.1 of the Standard No. 302, they may, in our opinion, be affected by requirements of para. S4.2, being separated from the bus interior only by a louvered panel. This area (which the filters occupy) cannot be clearly defined whether it falls into the category of occupant compartment air space. The copies of some selected pages from the bus service and parts manuals are attached for your reference. It would be greatly appreciated if you could clarify whether the A/C return air filters must conform to the Standard No. 302. If you need any additional information, please contact Sol. Zhodzishsky of my staff at tel. 718 927-7634 (fax 718 927-8079) I would like also to thank Mr. Marvin Shaw for his expedient response to our verbal inquiries. (MANUALS OMITTED.) |
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ID: nht95-6.22OpenTYPE: INTERPRETATION-NHTSA DATE: August 28, 1995 FROM: Joseph J. Smith -- Assistant Chief Maintenance Officer, Technical Services & Maintenance Support, Department of Buses, New York Transit Authority TO: John Womack -- Office of Chief Counsel, NHTSA TITLE: NONE ATTACHMT: ATTACHED TO 9/29/95 LETTER FROM JOHN WOMACK TO JOSEPH J. SMITH (A43; STD. 302) TEXT: Dear Mr. Womack: I am requesting interpretation of NHTSA Standard No. 302; Flammability of interior materials (49 CFR Ch. V, 10-1-94 Edition, para. 571.302). The Department of Buses, MTA New York City Transit, has been notified by a supplier of air conditioning (A/C) return air filters that their filters do not meet Standard No. 302. The A/C filters that the DOB utilizes on RTS 04 and 06 model buses are located on the top of A/C evaporator coil. Although the A/C filters are not mentioned in para. S4.1 of the Standard No. 302, they may, in our opinion, be affected by requirements of para. S4.2, being separated from the bus interior only by a louvered panel. This area (which the filters occupy) cannot be clearly defined whether it falls into the category of occupant compartment air space. The copies of some selected pages from the bus service and parts manuals are attached for your reference. It would be greatly appreciated if you could clarify whether the A/C return air filters must conform to the Standard No. 302. If you need any additional information, please contact Sol. Zhodzishsky of my staff at tel. 718 927-7634 (fax 718 927-8079) I would like also to thank Mr. Marvin Shaw for his expedient response to our verbal inquiries. (MANUALS OMITTED.) |
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ID: 86-4.17OpenTYPE: INTERPRETATION-NHTSA DATE: 07/18/86 FROM: ERIKA R. JONES -- CHIEF COUNSEL NHTSA TO: ROGER WILLIAMS -- PRESIDENT TECHNICAL HALLMARK ENTERPRISES, INC. TITLE: NONE ATTACHMT: UNDATED LETTER FROM ROGER WILLIAMS TO NHTSA TEXT: Dear Mr. Williams: This is in reply to your letter asking about regulations applicable to the "new lights that are now being seen on the trunk lids, and the rear windows of new automobiles". The specific legal name for this light is "center high-mounted stop lamp". It was optional for use as original equipment on passenger cars manufactured between August 1, 1984 and September 1, 1985. It has been mandatory original equipment since then. The Federal regulation that requires it is Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices, and Associated Equipment issued by the National Highway Traffic Safety Administration of the Department of Transportation. This standard specifies color, minimum illuminated lens area, mode of operation, etc. for original equipment, and for equipment intended to replace that original equipment. The standard does not cover center high-mounted stop lamps intended for use on cars that never had them, and a manufacturer of such aftermarket motor vehicle equipment is subject only to State laws on their design, installation, and use. We encourage aftermarket manufacturers to follow the Federal standard so that the full potential of the lamp may be realized. This means that the lamp should be steady-burning rather than pulsating, and that the lens not have logos, trademarks, or other markings on it to interrupt the transmission of light from the lamp. The standard does not specify the shape of the lamp but virtually all to date have been rectangular (photos of the 1987 Cadil ac Allante show a circular one), and some have exceeded the minimum requirement of a lens area of at least 4 1/2 square inches. Noting your interest as a prospective manufacturer of these devices, I enclose a copy of Standard No. 108. Sections 4.1.1.41 (page 218), Section 4.3.18 (page 227) and Table III (page 256) provide the relevant requirements for center high-mounted stoplamps. Should you proceed to manufacture aftermarket lamps, you would be subject to the agency's notification and remedy procedures should a safety related defect occur in them. Otherwise, you would appear to be subject only to State laws. Sincerely, ENCLOSURE |
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ID: 9886Open AIR MAIL Mr. S. Greiff PARS Passive Rhckhaltesysteme GmbH Borsigstrabe 2 63/55 Alzenau Germany Dear Mr. Greiff: This responds to your letter of April 19, 1994, requesting an interpretation of the 500 foot minimum runway length in the Laboratory Test Procedure for Federal motor vehicle safety standards Nos. 208, 212, 219, and 301. Laboratory Test Procedures are provided to contracted laboratories as guidelines for conducting compliance tests. The Laboratory Test Procedures do not limit the requirements of the applicable Federal motor vehicle safety standards. None of the standards referenced in your letter include any requirement for minimum runway length. Instead, the standards specify that the collision into the fixed barrier will occur at any speed up to and including 30 mph. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely,
John Womack Acting Chief Counsel ref:208 d:6/8/94
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1994 |
ID: nht87-3.36OpenTYPE: INTERPRETATION-NHTSA DATE: 12/04/87 FROM: WARD W REESER -- PROJECT ENGINEER ELECTRICAL SYSTEMS, CATERPILLAR INCORPORATION TO: TAYLOR VINSON -- NHTSA TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 08/08/88 TO WARD W. REESER FROM ERIKA Z. JONES; REDBOOK A32(2) VSA 102 TEXT: Dear Mr. Vinson: Caterpillar Inc. has initiated a program to review all of the lighting used on the entire Caterpillar product line throughout the world. We are attempting to standardize wherever possible those devices used in the U.S. and Canada, Europe, Japan, and Aus tralia. As you are aware, this line of construction and industrial equipment is basically for off-highway use. There are occasional uses on the highway for such equipment as motor graders, but obviously none of this equipment is designed for normal highway use or for the transportation of people. Specifically, we need to know if there are any lighting devices required under Federal Motor Vehicle Safety Standard No. 108 for the line of products shown in the attached brochure. An early reply would be appreciated. Sincerely, [CATERPILLAR INCORPORATION BROCHURE OMITTED] |
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.