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 |
|---|---|
| search results table | |
ID: nht94-8.30OpenDATE: February 7, 1994 FROM: Martin M. Sackoff, Ph.D. -- Executive Director Of Laboratories, International Testing Laboratories TO: Office of Chief Counsil -- NHTSA TITLE: None ATTACHMT: Attached To Letter Dated 5/12/94 From John Womack To Martin Sackoff (A42; Std. 109) TEXT: Gentlemen: The subject of this request is in reference with Motor Vehicle Safety Standard No. 109 - New Pneumatic Tires - Passenger Cars. The specific question is with reference to S4.2.2.4 Tire Strength, which states "S4.2.2.4 Tire Strength. Each tire shall meet the requirements for minimum breaking energy specified in Table 1 when tested in accordance with S5.3". I shall very much appreciate receiving a reply concerning the definition or interpretation of the term "breaking" of the tire. Does this mean a blowout of the tire, or simply the breaking of the tire caused by forcing the steel plunger into the tread? Thank you. Sincerely, |
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ID: 9017Open Erika Z. Jones, Esq. Dear Ms. Jones: This responds to your request for an interpretation of Federal Motor Vehicle Safety Standard No. 213, Child restraint systems. S5.2.3.2(b) of Standard No. 213 specifies a minimum thickness for materials of a certain compression-deflection resistance. You ask whether more than one piece of material may be used to meet the thickness requirement. The answer is yes. S5.2.3.2(b) does not require the material to be of a single piece, and the final rule that incorporated the requirement into Standard No. 213 did not address the issue. 44 FR 72131, December 13, 1979. Accordingly, more than one piece of material may be used. I hope this information is helpful. If you have any further questions, please contact us. Sincerely,
John Womack Acting Chief Counsel ref:213 d:10/7/93 |
1993 |
ID: nht72-3.46OpenDATE: 03/17/72 FROM: J.E. LEYSATH FOR E.T. DRIVER -- NHTSA TO: U.M. Electrical Distributers Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of March 6, 1972, concerning warning buzzers for the automobile industry. The National Highway Traffic Safety Administration has issued two safety standards which specify warning requirments. These requirements are given in Paragraph S4.4 of Standard 114 and Paragraph S7.3.1 of Standard 208. A copy of these two standards are enclosed for your review and further information. You will note that these standards do not stipulate minimum requirements for the warning devices, and, at the present time, we have no plans to specify such requirements. The data sheet, however, which you enclosed will be useful to us should we specify such requirements in future amendments to these standards. We appreciate your writing to us, and if we can be of any further service, please let us know. |
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ID: nht94-1.45OpenTYPE: INTERPRETATION-NHTSA DATE: February 7, 1994 FROM: Martin M. Sackoff, Ph.D. -- Executive Director Of Laboratories, International Testing Laboratories TO: Office of Chief Counsil -- NHTSA TITLE: None ATTACHMT: Attached To Letter Dated 5/12/94 From John Womack To Martin Sackoff (A42; Std. 109) TEXT: Gentlemen: The subject of this request is in reference with Motor Vehicle Safety Standard No. 109 - New Pneumatic Tires - Passenger Cars. The specific question is with reference to S4.2.2.4 Tire Strength, which states "S4.2.2.4 Tire Strength. Each tire shall meet the requirements for minimum breaking energy specified in Table 1 when tested in accordance with S5.3". I shall very much appreciate receiving a reply concerning the definition or interpretation of the term "breaking" of the tire. Does this mean a blowout of the tire, or simply the breaking of the tire caused by forcing the steel plunger into the tread? Thank you. Sincerely, |
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ID: nht74-3.42OpenDATE: 05/14/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Dave's Tire & Fuel Oil Corp. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letters of March 21 and April 22, 1974, in which you ask whether a tire sold as a "blemish" must be guaranteed for workmanship, material, and road hazards. There are no Federal requirements that manufacturers guarantee blemish (or non-blemish) tires. Such guarantees are within the discretion of each manufacturer. However, Federal Motor Vehicle Safety Standard No. 109 (49 CFR @ 571.109) requires all new passenger car tires to meet minimum safety performance levels for high speed performance, endurance, strength, bead unseating, physical dimensions and tradewear indicators. These requirements apply similarly to both blemish and non-blemish tires. We have enclosed for your information a copy of the Federal Trade Commission's Tire Advertising and Labeling Guides which contain in Guide 11 requirements for the labeling of blemish tires. ENC. |
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ID: nht93-7.14OpenDATE: October 7, 1993 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Erika Z. Jones -- Esq., Mayer, Brown & Platt TITLE: None ATTACHMT: Attached to letter dated 8/17/93 from Erika Jones to John Womack (OCC-9017) TEXT: This responds to your request for an interpretation of Federal Motor Vehicle Safety Standard No. 213, Child restraint systems. S5.2.3.2(b) of Standard No. 213 specifies a minimum thickness for materials of a certain compression-deflection resistance. You ask whether more than one piece of material may be used to meet the thickness requirement. The answer is yes. S5.2.3.2(b) does not require the material to be of a single piece, and the final rule that incorporated the requirement into Standard No. 213 did not address the issue. 44 FR 72131, December 13, 1979. Accordingly, more than one piece of material may be used. I hope this information is helpful. If you have any further questions, please contact us. |
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ID: nht92-6.26OpenDATE: May 29, 1992 FROM: Berkley C. Sweet -- Vice-President, School Bus Manufacturers Institute TO: Barry Felrice -- Associate Administrator for Rulemaking, NHTSA TITLE: Subject: Standard No. 222, School Bus Passenger Seating and Crash Protection ATTACHMT: Attached to letter dated 7/28/92 from Paul J. Rice to Berkley C. Sweet (A39; Part 571.3) TEXT: Based on the requirements specified in the Standard No. 222 for Seat Performance Forward, Seat Performance Rearward and the Head Protection Zone, what was the minimum size of the passenger (eight and height) used to establish the design criteria of this standard? Several school districts are now transporting new born and under school-age children with their parents to a school that provides a day-care service, while the parent attends classes. The School Bus Manufacturers Institute has received inquiries as to limits, if any, on passenger size and age that can be safely transported on school bus seats. |
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ID: nht90-4.26OpenTYPE: Interpretation-NHTSA DATE: September 28, 1990 FROM: Takahiro Maeda -- Assistant to the Vice President, Engineering Divison, Yamaha Motor Corporation, U.S.A.; Signature by Michael Schmitt TO: Office of Chief Counsel, NHTSA TITLE: Re FMVSS 108 ATTACHMT: Attached to letter dated 12-7-90 to T. Maeda from P.J. Rice (A36; Std. 108) TEXT: The purpose of this correspondence is to obtain your interpretation of minimum "edge to edge" separation between the tail/stop lamp and turn signals pursuant to FMVSS 108 Table IV. Tail/stop lamp design may feature a housing whereby the bulb reflector subassembly does not extend outward to the edge of the entire assembly. Can "edge to edge" be construed as the edge of the bulb reflector or is it necessarily the outer edge of the en tire tail/stop lamp assembly. Please refer to the attached illustration. We thank you for your insight into this question. Attached illustration. (Graphics omitted) |
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ID: 11373JEGOpen B. Michael Korte, Esq. Dear Mr. Korte: This responds to your letter asking about Federal standards concerning the deployment of air bags. You asked whether AFederal regulations establish a minimum speed that vehicles must be traveling, below which an air bag will not deploy.@ The answer to your question is no. Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection, establishes a number of performance requirements for air bags and air-bag-equipped vehicles. However, neither that standard nor any other Federal motor vehicle safety standard specifies that air bags must not deploy in crashes below a specified vehicle speed. I hope this information is helpful. If you have any other questions, please contact Edward Glancy of my staff at this address or by phone at (202) 366-2992. Sincerely,
Samuel J. Dubbin Chief Counsel Ref:208 d:1/29/96 NCC-20 Eglancy:mar:1/3/96:OCC 11373 |
1996 |
ID: nht72-1.33OpenDATE: 06/27/72 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Checker Motors Sales Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 25, 1972, asking whether you, as a selling dealer, may install steel-belted radial ply tires on an 8-passenger Checker taxicab. You state that the vehicle is normally delivered to you with tires having the "D" load range. Federal Motor Vehicle Safety Standard No. 110 (49 CFR 571.110, copy enclosed) requires each passenger car to be equipped at the time of sale to a first purchaser with tires of certain minimum load carrying capacity, based on the weight of the vehicle. Any steel-belted radial ply tire that meets these load carrying requirements with respect to your vehicles may be installed by a selling dealer. Radial tires of similar or related sizes, but of different manufacture, however, may have different load ratings. We suggest, therefore, that you contact Checker Motor Corporation for their recommendations as to which radial ply tires may be installed on these vehicles without adversely affecting the vehicle's conformity with Motor Vehicle Safety Standard No. 110. |
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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.