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: nht88-3.52OpenTYPE: INTERPRETATION-NHTSA DATE: 09/14/88 FROM: WENDELL D. KEGG -- TIRE WHEEL CONSULTANTS TO: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 01/1/8/89 FROM ERIKA Z. JONES -- NHTSA TO WENDELL D. KEGG, REDBOOK A33, STANDARD 109 TEXT: Dear Ms. Jones: I am confused by the FMVSS 110 Standard. As I read Paragraph S4.3.1 covering inflation pressure on the vehicle placard, the tire cannot by inflated beyond that maximum pressure embossed on the tire. Subparagraph S4.3.1(c) is not clear. Can a vehicle manufacturer specify a higher inflation pressure in a spare tire application than that which is embossed on the sidewall of the tire? Thank you. Very truly yours, |
|
ID: nht69-2.9OpenDATE: 03/27/69 FROM: AUTHOR UNAVAILABLE; Francis Armstrong; NHTSA TO: Gold Cross Ambulance Service Inc. TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of January 18, 1969, to Dr. William Haddon, Jr., requesting information on Federal Motor Vehicle Safety Standards (FMVSS) applicable to ambulances. If the ambulance is built on a passenger car chassis, all of the FMVSS applicable to passenger cars would apply. However, if the ambulance is built on a truck chassis, the FMVSS applicable to multi-purpose passenger vehicles would apply. There have been no special exceptions granted for ambulances. Enclosed for your information and guidance are copies of the National Traffic and Motor Vehicle Safety Act of 1966 and the FMVSS established thereunder. |
|
ID: nht92-1.3OpenDATE: December 30, 1992 FROM: Donald L. Anglin -- Consulting Editor, MacMillan/McGraw-Hill Publishing, Automotive and Technical Writing TO: William A. Boehly -- Director, Office of Vehicle Safety Standards, NHTSA TITLE: None ATTACHMT: Attached to letter dated 4-19-93 from John Womack to Donald L. Anglin (A41; Redbook (4); Std. 105; Std. 121) TEXT: Your assistance in the past has certainly been appreciated and informative. So may we ask for your insight into another issue affecting highway safety. Does the removal of drum-brake self-adjusters from a vehicle constitute a violation of the anti-tampering provisions of the Clean Air Act, the National Traffic and Motor Vehicle Safety Act, or any other Federal law, regulation, or standard? As always, thank you very much for your continuing interest and assistance. |
|
ID: nht76-4.26OpenDATE: 09/09/76 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: B. F. Goodrich Engineered Systems Company TITLE: FMVSS INTERPRETATION TEXT: This responds to your July 26, 1976, question whether the "no lockup" requirement of S5.3.1 and S5.3.2 of Standard No. 121, Air Brake Systems, requires wheel sensors on both axles of a tandem axle system in those cases where the "no lockup" performance is provided by means of an antilock system. I have enclosed a detailed discussion of this issue that responded to a similar question from another manufacturer. The response should answer your question. Yours truly, Enclosure ATTACH. B.F. Goodrich Engineered Systems Company July 26, 1976 JOHN W. SNOW -- ADMINISTRATOR -- National Highway Traffic Safety Administration Subject: REQUEST FOR CLARIFICATION OF MVSS 121 Gentlemen: Section S.5.3.1.A (for trucks and buses) and Section S.5.3.2.A (for trailers) of MVSS 121 states that wheel lock-up shall not occur on any wheel above 10 M.P.H., except for controlled lock-up of wheels allowed by an anti-lock system. It is understood that a manufacturer is not required to utilize an anti-lock system to meet the "no lock-up" requirement, however, if a manufacturer does choose to utilize the "controlled lock-up" exception of S.5.3.1.A and S.5.3.2.A, by installing an anti-lock system, it must control the lock-up of the wheels which are pneumatically controlled by that system (reference attached copy of letter dated March 7, 1975 to Harold D. Shall from James C. Shultz). Therefore, it is our interpretation that the vehicles' anti-lock system, if included, must include a wheel speed sensor on each wheel, that is pneumatically controlled by the anti-lock logic module valve. Is this correct? We will appreciate your official ruling on this pressing matter at your earliest convenience. Very truly yours, Richard J. Brandewie -- Program Manager, Highway Products cc: D. L. Haines; C. D. McCarty |
|
ID: nht88-4.9OpenTYPE: INTERPRETATION-NHTSA DATE: 11/14/88 FROM: F. J. TRECY -- GENERAL MANAGER, MANUFACTURING MILLER STRUCTURES INC TO: ERIKA Z. JONES -- CHIEF COUNSEL NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 12/30/88 FROM ERIKA Z. JONES -- NHTSA TO FRANK J. TRECY, REDBOOK A33 (4), VSA 102 (3), STANDARD 115; LETTER DATED 10/04/88 FROM FRANK J. TRECY TO ERIKA Z. JONES TEXT: Dear Ms. Jones: On October 4, 1988 I wrote asking for an interpretation of the Federal Motor Vehicle Safety Standard No. 115, Subpart S2, Titled: Application. I need your interpretation before January 1, 1989 whether or not our unique and specialized products require the VIN identification numbering system. I am enclosing a copy of my October 4, 1988 letter. Thanking you in advance, I remain, Sincerely, ENCLOSURE |
|
ID: nht79-3.24OpenDATE: 10/12/79 FROM: AUTHOR UNAVAILABLE; Stephen P. Wood; NHTSA TO: Phillips Motor Car Corporation TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of September 22, 1979, asking whether Phillips Motor Car Corporation is a "manufacturer" or "alterer" of the Berlina Coupe. As you have described it, Phillips removes the body from a 1980 Corvette, lengthens the frame and install newly manufactured body parts, retaining the interior safety features of the original vehicle. It is clear from your description that Phillips alters previously certified vehicles "other than by the addition, substitution, or removal of readily attachable components such as mirrors or tires and rim assemblies . . ." and is, therefore, subject to the certification requirements of Title 49, Code of Federal Regulations, Section 567.7. I enclose a copy of the regulation for your information and would be pleased to answer such further questions as you may have. |
|
ID: nht81-2.43OpenDATE: 07/07/81 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Carabela USA, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of June 8, 1981 requesting "the candlepower rating on a moped headlamp." I enclose a copy of SAE Standard J584 Motorcycle and Motor Driven Cycle Headlamps April 1964, which contains the information that you request. Most mopeds develop 5 horsepower or less and thus qualify as a "motor driven cycle." If you have any further questions, we shall be pleased to answer them. ENC. Carabela USA, Inc. 6-8-81 Office of Chief Council NHTSA Dear Mr. Schwartz: Please quote me the candlepower rating on a moped headlamp, if any. Thank you. Barry N. Aebischer Mktg. Coordinator |
|
ID: nht71-2.25OpenDATE: 04/13/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Tire Retreading Institute TITLE: FMVSR INTERPRETATION TEXT: This is in response to your letter of December 28, 1970, to Roger Comptom, requesting an interpretation whether the Tire Identification and Record Keeping Regulation (49 CFR 574) is applicable to retreaded tires sold to the General Services Administration (GSA); and, if the regulation is applicable, what will GSA be considered to be; a distributor, a dealer, or a first purchaser for purposes other than resale. The regulation is applicable to both new and retread tires sold to GSA. We consider GSA to be a "purchaser" under the regulation, and the manufacturer or retreader is required to maintain records of the purchaser's name and address and the identification number of the tires sold to them. However, as you must realize, individual arrangements on a contractual basis between GSA and its suppliers are not precluded by the regulation. |
|
ID: nht93-8.37OpenDATE: November 30, 1993 FROM: Lynn White -- President, Industrial Metal Fabricators TO: Jeff Boraston -- Remediquip International Manufacturing TITLE: Portable Trailers 45590 and 50690 ATTACHMT: Attached to letter dated 1/26/94 from John Womack to Ramin Bogzaran (A42; VSA 102(3)); Also attached to letter dated 12/1/93 from Ramin Bogzaran to John Womack; Also attached to fax dated 12/15/93 from Ramin Bogzaran to Marvin Shaw; Also attached to letter dated 11/15/93 from Amar Chhabra to whom it may concern TEXT: The above equipment manufactured by IMF, Inc. in 1990 and 1991 meet or exceeded all requirements of the United States Department of Transportation. I am also sending copies of the original Bill of Lading. If I can provide additional information, please call.
Attachments (text and graphics omitted): Exporter's Certificate of Origin Photographs |
|
ID: 77-2.15OpenTYPE: INTERPRETATION-NHTSA DATE: 04/18/77 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: AM General Corporation TITLE: FMVSS INTERPRETATION TEXT: This responds to your oral request of March 28, 1977, for clarification of the language of S5.4.1 of Standard No. 217, Bus Window Retention and Release. In particular, you ask whether the long side of a rectangular roof exit is required to be parallel to the center line of a bus. S5.4.1 requires that an exit provide "an opening large enough to admit unobstructed passage, keeping a major axis horizontal at all times, of an ellipsoid generated by rotating about its minor axis an ellipse having a major axis of 20 inches and a minor axis of 13 inches." Further, S5.2.1 of the standard states that a roof exit shall meet these requirements when the bus is overturned on either side. The requirement that the major axis be kept horizontal while the bus is on its side means that the major axis, and therefore the long side of the rectangular roof exit, would be parallel to the center line or the side wall of a bus. 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.