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: nht88-1.99OpenTYPE: INTERPRETATION-NHTSA DATE: April 18, 1988 FROM: ERMAN JACKSON -- SALES MANAGER-TRAILMASTER TANKS TO: ERIKA Z. JONES -- NHTSA CHIEF COUNSEL ATTACHMT: DECEMBER 9, 1988 LETTER FROM JONES TO JACKSON TEXT: As per the suggestion of Ms. Joan Tilghman, of the office of the Chief Council, I am writing to you in regards to an answer to a question that has occurred with a customer of ours. We mounted a new body on truck chassis which had been in service a numbe r of years. This truck was not modified in any way at the time of the installation. Our customer is in the opinion that we should issue a new Final Stage Manufacture Certificate at the time of the mounting of the new body. We on the other hand, are in the opinion that the Final Stage Manufacture Certificate is only issued when the chassis is new. We would appreciate it if you could respond to this question in writing so that we may foreward it to our customer. Thank you for your consideration. |
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ID: nht94-4.35OpenTYPE: INTERPRETATION-NHTSA DATE: September 23, 1994 FROM: Andrea Seastrand -- California State Assemblywoman TO: John Womack, Acting Chief, NHTSA TITLE: N ATTACHMT: ATTACHED TO LETTER DATED 12/6/94 FROM PHILIP R. RECHT TO ANDREA SEASTRAND (A42; STD. 119) TEXT: Enclosed is a copy of a Casework Intake Form on behalf of my constituent, Mr. Eric Brandt. Please provide me with information on how to best advise Mr. Brandt and address him personally in your response. Please direct your response to my San Luis Obisp o district office. Thank you in advance for your attention in this matter. |
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ID: nht71-3.9OpenDATE: 05/25/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Hicks Oil Company TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of April 28, 1971. Under Part 574, the tire identification number may be placed on the side of the top cap areas or may be branded into the tire in accordance with the regulation. If the top cap area is used, the number should be as close to the sidewall as in feasible so that the number will remain legible as long as possible. See the enclosed amendment on this subject (Docket No. 70-12; Notice No. 9). |
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ID: nht73-5.46OpenDATE: 10/09/73 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Paulson and Humphreys COPYEE: MR. PESCOE; MR. HELLMUTH TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your communication of September 20, 1973, requesting our review of a sample owner notification letter, regarding a safety related defect in certain Apache Camping Trailers, for purposes of conformity to 49 CFR Part 577, Defect Notification. We believe the reference in the first sentence of the second paragraph, that a defect may exist, to be inconsistent with the regulation. This statement is apparently intended to meet the requirement of Section 577.4(b). This subsection, however, requires a particular statement and does not permit the use of "many" or similar expression. The statement required is not solely one of fact, but rather one of law, and the opening sentence of Section 577.4(b) shows clearly that the statement is required where the defect potentially exists in the vehicles or equipment in question. We also believe your references in other parts of the letter to "possible defect" suffer from the same deficiency. In other respects, we believe your notification letter conforms to Part 577. |
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ID: nht72-2.50OpenDATE: 05/01/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Labelmaster TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of April 11, 1972, in which you ask whether four samples which you submit of labels for retreaded tires will meet the requirements of S6.2 and S6.3 of Motor Vehicle Safety Standard No. 117. Each of the labels, with either the appropriate information filled in or clearly indicated by an "X" or other mark will meet the requirements of the standard. In the case of styles "C" and "D", however, either "2-ply" or "4-ply" will have to be deleted by the retreader, as one tire, of course, cannot be both a 2-ply and 4-ply tire. An alternative would be to eliminate the reference to plies, as stating the ply rating by itself is sufficient under the standard. We are pleased to be of assistance. |
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ID: nht94-1.100OpenTYPE: Interpretation-NHTSA DATE: March 25, 1994 FROM: James Ackley -- Region 4 Director; Carol Baumhauer -- Counselor; Krista D. Subler -- Counselor -- Small Business Development Center, Upper Valley JVS Business Development Center TO: John E. Boehner TITLE: None ATTACHMT: Attached to letter dated 6/25/94 Est from John Womack to John A. Boehner (A42; Std. 108; VSA S102(a)(2)(A) and letter dated 4/7/94 from John A. Boehner to Jackie Lowey TEXT: We are writing in reference to clients of the Upper Valley Small Business Development Center in Piqua. Mr. John Cail and Mr. James Lipps are inventors with a patent on a product called Life Lites. Because this system has the potential to save lives, we request your assistance in guiding Mr. Cail and Mr. Lipps through the color code designation process and any other resource possibilities available. We appreciate your consideration in this matter. |
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ID: nht94-7.24OpenDATE: March 25, 1994 FROM: James Ackley -- Region 4 Director; Carol Baumhauer -- Counselor; Krista D. Subler -- Counselor -- Small Business Development Center, Upper Valley JVS Business Development Center TO: John E. Boehner TITLE: None ATTACHMT: Attached to letter dated 6/25/94 Est from John Womack to John A. Boehner (A42; Std. 108; VSA S102(a)(2)(A) and letter dated 4/7/94 from John A. Boehner to Jackie Lowey TEXT: We are writing in reference to clients of the Upper Valley Small Business Development Center in Piqua. Mr. John Cail and Mr. James Lipps are inventors with a patent on a product called Life Lites. Because this system has the potential to save lives, we request your assistance in guiding Mr. Cail and Mr. Lipps through the color code designation process and any other resource possibilities available. We appreciate your consideration in this matter. |
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ID: nht73-4.24OpenDATE: 06/01/73 FROM: AUTHOR UNAVAILABLE; J. E. Wilson; NHTSA TO: General Motors Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 11, 1973, asking for confirmation of your interpretation of paragraph S7.9 of Standard No. 105a in terms of General Motors' air vacuum power brake. Your interpretation is correct. Your system with its "two separate and independent energy sources in the power head . . . is equivalent to two entirely duplicate systems", and disconnection of one source at a time would be the correct test procedure under S7.9, provided the requirements of S5.1.3 are satisfactorily met under both conditions. |
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ID: nht69-2.19OpenDATE: 12/02/69 FROM: AUTHOR UNAVAILABLE; R. H. Compton; NHTSA TO: Thompson Aircraft Tire Corporation TITLE: FMVSS INTERPRETATION TEXT: In response to your letter of November 6, 1969, the Department of Transporation hereby assigns number 211 to the Thompson Aircraft Tire Corporation, South San Francisco, California, as its approved code mark. The approved code mark is for use in identifying the tire manufacturer in accordance with S4.3 of the Federal Motor Vehicle Safety Standard No. 109 and the National Traffic and Motor Vehicle Act of 1966 (15 USC 1421(1)). You are cautioned that the approved code mark at the present time is for use only on new pneumatic passenger car tires. |
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ID: nht69-2.6OpenDATE: 01/16/69 FROM: AUTHOR UNAVAILABLE; William Haddon, Jr., M.D.; NHTSA TO: Rolls-Royce Limited Motor Car Division TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of November 8, 1968, requesting a clarification of the 30g horizontal inertia load direction specified in Standard No. 201, as published in the Federal Register on October 25, 1968. In section S3.3.1(c), "Subject the interior compartment door latch system to a horizontal inertia load of 30g in a longitudinal direction....." means both forward and rearward directions. In addition, the loads specified in S3.3.1(a) are applied in both the inboard and outboard and the up and down directions. This is consistent with similar type requirements in Standard No. 206. You state that a forward and rearward 30g inertia load requirement is more stringent than the alternative procedure of S3.3.1(b), the barrier test. The Bureau believes, and one large manufacturer so stated in his comments, that the most meaningful test of the ability of an interior compartment door to remain closed is one which considers the distortion and deformation loads that occur in a collision. A barrier or equivalent dynamic test is the best way of realistically evaluating the ability of these doors to remain closed. The Bureau, therefore, believes that the barrier test is as stringent a requirement as S3.3.1(c). |
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.