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: nht74-1.30OpenDATE: 02/15/74 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Maserati, S.p.A. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of January 22, 1974, asking whether paragraph S4.3.1 of Motor Vehicle Safety Standard No. 108 precludes the mounting of rear lamps in a transparent "Lexan" panel "not involved in the driver's rearward vision." Paragraph S4.3.1 states in pertinent part that ". . . each lamp . . . shall be securely mounted on a rigid part of the vehicle other than glazing that is not designed to be removed except for repair . . . ." The "glazing" referred to is the glazing regulated by Standard No. 205, and refers generally to glazing used in windshields, windows, doors, and interior partitions. Accordingly, Standard No. 108 does not preclude the mounting of rear lamps in the "Lexan" panel. Yours truly, ATTACH. OFFICINE ALFIERI MASERATI S.p.A. January 22, 1974 National Highway Traffic Safety Administration -- Office of Chief Counsel; Attention: Mr. Vinson Subject: Request for clarification of MVSS No. 108, Paragraph S.4.3.1. Gentlemen: Since we are planning to introduce soon in the United States our new model, the "KHAMSIN" (model 120), we would very much appreciate your clarifying the intent of paragraph S.4.3.1. of Motor Vehicle Safety Standard No. 108 -- "Lamps, Reflective Devices and Associated Equipment." Paragraph S.4.3.1 of MVSS No. 108 states that "each lamp . . . . . shall be securely mounted on a rigid part of the vehicle other than glazing that is not designed to be removed except for repair, . . .". As you will see in the enclosed documents, the "KHAMSIN" is a two door GT coupe which embodies, as a new styling concept, a rear end panel made of transparent "Lexan" material. The two rear combination lamps are securely mounted on this Lexan panel. The Lexan material is a polycarbonate sheet, produced by the General Electric Company under the designation "LEXAN MR-4000". It is especially treated on both sides in order to make it scratch resistant. It is completely collision proof and is classified by the "Underwriters' Laboratories Inc." as the sole transparent antilock-picking material. The mounting of the rear combination lamps on the rear end panel is described in the enclosed blueprint No. 120 VS 83090 and shown on the 2 enclosed B & W photographs. This tansparent rear end panel is not involved in the driver's rearward vision and it is transparent only for aesthetic purposes. It is permanently mounted on the vehicle and its replacement constitutes a major repair. We believe that paragraph S.4.3.1 of Standard No. 108 was intended to prevent mounting of lamps on glazing material which concurs to the driver's vision (such as windows), but since the wording of this paragraph is not clear to us, we would appreciate very much your clarifying if mounting the rear lamps such as it is done on the KHAMSIN does comply with MVSS No. 108. Thanking you very much in advance for a prompt answer, we remain at your disposal should you need more information on this matter. Very truly yours, Bernard Belier -- U.S. Resident Engineer for MASERATI S.p.A. |
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ID: nht71-2.20OpenDATE: 03/24/71 FROM: AUTHOR UNAVAILABLE; Francis Armstrong; NHTSA TO: AGIP USA Inc. TITLE: FMVSS INTERPRETATION TEXT: This office is in receipt of your letter of February 25, 1971, requesting concurrence with your proposed letter to an automobile manufacturer who wishes to import vehicles into the United States using your brake fluid. Your proposed letter appears to adequately state the responsibility of the vehicle manufacturer, and as your letter indicates, the National Highway Traffic Safety Administration doesn't require that certification tests be conducted at Government approved laboratories. However, if your company plans to import brake fluid into the United States as an item of motor vehicle equipment rather than a part of a vehicle, proof of certification must be supplied by AGIP upon our request. We trust this will answer your questions. |
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ID: nht90-4.51OpenTYPE: Interpretation-NHTSA DATE: October 31, 1990 FROM: Toni Fargo -- Executive Secretariat, Office of the Secretary of Transportation TO: NHTSA TITLE: Re REVIEW OF ARBITRARY AND CAPRICIOUS ACTION BY THE NHTSA AND APPROVE JOHN A. ROSATTI'S PROPOSED IMPORTATION OF HIS PROSCHE 959 AS A "DEMONSTRATION" VEHICLE ATTACHMT: Attached to letter dated 1-3-91 to Stephen C. Crampton & Marc J. Fink from Jerry Ralph Curry (A37; Part 591; Sec 1397); Also attached to letter dated 10-30-90 to Samuel K. Skinner from Marc J. Fink & Stephen C. Crampton TEXT: IF YOU ARE UNABLE TO PROVIDE THE REQUIRED INFORMATION, PLEASE ADVISE YOUR ANALYST NO LATER THAN 24 HOURS AFTER THE RECEIPT OF THIS DOCUMENT. THIS SHEET MUST REMAIN WITH THE INCOMING DOCUMENT AND BE RETURNED WITH YOUR RESPONSE. YOUR PROMPT ACTION IS AP PRECIATED. |
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ID: nht89-1.26OpenTYPE: INTERPRETATION-NHTSA DATE: 02/24/89 FROM: DAN TREXLER -- THOMAS BUILT BUSES TO: JOAN TILGHMAN -- NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 08/03/89 EST; FROM STEPHEN P. WOOD -- NHTSA TO L.T. MITCHELL -- THOMAS BUILT BUSES INC; REDBOOK A33; STANDARD 217; LETTER DATED 04/27/88 FROM L.T. MITCHELL -- THOMAS BUILT BUSES INC; TO ERIKA Z. JONES -- NHTSA; LETTER D ATED 12/20/84 FROM FRANK BERNDT -- NHTSA TO MELVIN SMITH -- ILLINOIS DOT TEXT: Dear Ms. Tilghman, Several months ago I spoke with you over the phone regarding the enclosed letter. Please let me know if we can expect a response i.e., interpretation, to this in the near future. Thank you for your consideration. Sincerely, Enclosures |
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ID: nht87-3.29OpenTYPE: INTERPRETATION-NHTSA DATE: NOVEMBER 18, 1987 FROM: DAVIS THEKKANATH -- SR. SUPERVISING ENGINEER, OSHKOSH TRUCK CORPORATION TO: CHIEF COUNSEL -- NHTSA TITLE: FMVSS 121 ATTACHMT: MEMO DATED 9-12-88, TO DAVIS THEKKANATH, FROM ERIKA Z. JONES-NHTSA, STD 121 TEXT: Section 5.1.1. of the subject regulation addresses air compressor capacity requirements in terms of pump up time, to bring the reservoir pressure from 85 psi to 100 psi for trucks and buses. What happens when the truck has a trailer behind it? Does the air compressor capacity requirement include the volume of service reservoirs for the trailer too? My conversation this morning with Mr. Richard Carter of your office indicates that only the truck's service reservoirs have to be considered for the pump up time. Please confirm. Thank you, |
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ID: 8514Open Mr. Greg Hixson Dear Mr. Hixson: This responds to your March 30, 1993, letter asking for information on any regulations concerning aftermarket airbags. I am enclosing two letters dated March 26, 1993, to Mr. Steven C. Friedman and Mr. Jay Lee that explain the operation of Federal law with respect to aftermarket airbags. I am also enclosing a copy of the information sheet referred to in both letters. 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 Enclosures ref:208 d:4/15/93 |
1993 |
ID: nht93-3.4OpenDATE: April 16, 1993 FROM: John Womack -- Acting Chief Counsel, U.S. Department of Transportation, NHTSA TO: Greg Hixson -- President, Hixson and Netherton Distributing TITLE: None ATTACHMT: Attached to letter dated 3-30-93 from Greg Hixson to NHTSA (OCC 8514) TEXT: This responds to your March 30, 1993, letter asking for information on any regulations concerning aftermarket airbags. I am enclosing two letters dated March 26, 1993, to Mr. Steven C. Friedman and Mr. Jay Lee that explain the operation of Federal law with respect to aftermarket airbags. I am also enclosing a copy of the information sheet referred to in both letters. 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. |
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ID: nht95-1.88OpenTYPE: INTERPRETATION-NHTSA DATE: March 6, 1995 FROM: Dirk Du Plooy -- Motorcycle Safety Consultant, Motorcycle Rider Advancement Centre TO: Joe Pesci -- NHTSA TITLE: NONE ATTACHMT: ATTACHED TO 4/10/95 LETTER FROM PHILIP RECHT TO DIRK DU PLOOY (A43; PART 571.3(B) TEXT: Dear Sir, I received your details from the Motorcycle Safety Foundation (I am an MSF Instructor), I request your assistance in acquiring information about the U.S. laws on motorcycle trailers. We are currently drafting legislation legalising motorcycle trailers. I understand that there could be a number of different U.S. states with different laws, but the most generally accepted standard is what we need as a guide. I hope you can find time to assist us - your help will be appreciated. DIRK DU PLOOY MOTORCYCLE SAFETY CONSULTANT |
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ID: nht90-1.60OpenTYPE: INTERPRETATION-NHTSA DATE: MARCH 2, 1990 FROM: HENRY J. NOWAK -- MEMBER OF CONGRESS TO: GENERAL JERRY RALPH CURRY -- ADMINISTRATOR, NHTSA TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 3-16-90 TO BARBARA J. KELLEHER-WALSH, HARTLEY ASSOCS. INC., FROM STEPHEN P. WOOD, NHTSA; [REDBOOK A35; STD. 213]; ALSO ATTACHED LETTER DATED 2-20-90 TO HENRY J. NOWAK FROM BARBARA J. KELLEHER-WALSH, AND LETTER DATED 8-2 2-89 TO DEIRDRE FUJITA, OFFICE OF GENERAL COUNSEL FROM BARBARA J. KELLEHER-WALSH. TEXT: Enclosed is self-explanatory correspondence from my constituent, Ms. Barbara J. Kelleher-Walsh. I am requesting that very careful attention and consideration be expedited in providing Ms. Kelleher-Walsh the letter of interpretation, and please provide me a written response. With best wishes and kindest regards. ENCS. |
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ID: 20937.ztvOpen [ ] Dear: This is in reply to your letter of November 4, 1999, asking whether a lighting device you describe would be permissible under Federal Motor Vehicle Safety Standard No. 108. You requested that we keep your letter and our reply "in strict confidence." As Taylor Vinson of this Office informed you on December 2, 1999, our interpretations are publicly available and must contain sufficient information for the general public to understand the question being asked and our response to it. We can ensure that publicly available copies of interpretation letters do not identify the writer or the company involved, and you agreed that we could provide you an interpretation on this basis. You report that "tractor/trailer combinations today have areas around the vehicle where the driver cannot see other vehicles that are passing them. These blind spots in the mirror systems can cause accidents." You are interested in a lighting device that " would be mounted high on the side of a trailer and would shine a light beam (laser or other type of lighting device) down and across the adjacent traffic lane." The light "would shine on the hood of a passing vehicle" thereby providing the driver with a warning that they are in the tractor trailer's blind spot." The color of the light would be yellow, blue, or red. Under Standard No. 108, non-standard lighting devices are permitted as original equipment if they do not impair the effectiveness of lighting devices required by Standard No. 108. Although this device would not appear to impair the effectiveness of standard lighting equipment, we are concerned that it might impair driver performance. Our principal reservation about new lighting concepts such as this is that they are unfamiliar to drivers and will cause confusion, diverting attention from critical driving tasks. In this case, a driver finding a red, amber, or blue light suddenly shining on the vehicle hood may instinctively turn to see where it is originating, or brake when there is no need to do so. When a vehicle is traveling faster than a trailer on which the device is mounted, the light beam could proceed from the hood into the passenger compartment, at least on open cars, possibly temporarily blinding the driver. Thus, the device you describe could create actual hazards. You must remember, too, that a state may apply its own laws to auxiliary lighting devices and require specific approval to use them. Virtually all states reserve the color blue for emergency signals. Standard No. 108 does not permit side marker lamps and reflectors to be red except when they are mounted as far to the rear as practicable, and we apply this requirement to auxiliary side lighting devices as well. If you have further questions, you may call Taylor Vinson (202-366-5263). Sincerely, |
2000 |
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.