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: nht94-4.54OpenTYPE: INTERPRETATION-NHTSA DATE: October 18, 1994 FROM: Roger W. Cole -- Vice President, Sales, Twin Tire U.S.A., Inc. TO: Walters Meyers, Esquire -- NHTSA TITLE: None ATTACHMT: ATTACHED TO LETTER DATED 12/7/94 FROM PHILIP R. RECHT TO ROGER W. COLE (A42; REDBOOK 4; STD. 109; PART 575.105 TEXT: It was a pleasure speaking with you this morning on the telephone. To review our conversation, we are in the business of marketing and selling the Twin Tire system in the USA and abroad and are currently in discussions with various tire manufacturers. Most recently, our tires have been manufactured by Yokohama Rubber C orporation. These tires were manufactured as recently as 1991. All of these tires have a D.O.T. designation and a U.T.Q.G. designation. Yokohama has recently breached their contract to manufacture these tires under the premises of US regulations. Please confirm in writing that once the tires have received the D.O.T. and U.T.Q.G. approvals and ratings which are molded on the exterior of the tire that they are legal to sell in the US. I thank you very much and would appreciate a quick response as we are urgently in need of product. |
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ID: nht71-5.19OpenDATE: 12/10/71 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Oshkosh Truck Corporation TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of December 1, 1971, enclosing a diagram of a revised "Vehicle Identification Plate," and requesting our approval, based on the Certification regulations. Your submission of this revised diagram is in response to our letter to you dated November 10, 1971, wherein we disapproved of an earlier version of the identification plate due to the manner in which the axle manufacturer's ratings of the axles were presented. In your revised diagram, you refer to the ratings in question as the axle manufacturers "gross weight ratings." We believe that this language is still subject to being easily confused with the GAWR required on the Certification label, and we cannot conclude that wording the label in this fashion is consistent with the Certification regulations. In our letter of November 10 we stated, "If you wish to provide information based on the vehicle's axle capability, we prefer that it not be represented as a vehicle or axle weight rating, but that it be described as the axle manufacturers rating of the axles." Thus, in our opinion elimination of the words "gross weight" from your revised label will eliminate the conflict between your vehicle identification plate and the Certification requirements. |
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ID: nht79-3.9OpenDATE: 11/14/79 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Volvo of America TITLE: FMVSS INTERPRETATION TEXT: This is in response to the questions that you addressed to Mr. Hugh Oates over the telephone with regard to auxiliary fuel tanks. I have enclosed a copy of a letter which was sent to a company that planned to manufacture auxiliary fuel tanks for passenger cars and to do some installation. The principles enunciated in that letter are applicable to auxiliary fuel tanks intended for use in all types of motor vehicles except motor carriers in interstate commerce. If you have any further questions after reading the enclosed letter please feel free to contact Ms. Debra Weiner of my office who is familiar with the issues arising from the manufacture and use of auxiliary fuel tanks. |
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ID: Wagar.1OpenMr. Terry W. Wagar Dear Mr. Wagar: This responds to your e-mail of June 2, 2003, asking whether a proposed New York State bill (A5226) would be preempted by Federal law, in light of a possible inconsistency with Federal Motor Vehicle Safety Standard (FMVSS) No. 111, Rearview mirrors (49 CFR 571.111). Your correspondence attached a version of the bill and expressed concern regarding an amendment to existing State law that would require motor vehicles sold in New York (except motorcycles) to be equipped with a blind spot mirror. I would note that except for a change in dates, it is our understanding that the New York Assembly sought to pass a nearly identical provision in 1996 (A9376, March 5, 1996). In the enclosed interpretation letter to Mr. R. Karbowski, we stated that the proposed State requirement would be preempted under 49 U.S.C. 30103(b). Because the State legislative provision and the applicable Federal laws have remained essentially unchanged in relation to this matter, NYS bill A5226 would be similarly preempted for the reasons set forth in our earlier interpretation letter. If you have any further questions, please feel free to contact Eric Stas of my staff at this address or by telephone at (202) 366-2992. Sincerely, Jacqueline Glassman Enclosure |
2003 |
ID: nht71-5.65OpenDATE: 12/17/71 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: FWD Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of November 18, 1971, requesting for twenty-six of your trucks a temporary exemption from Standard No. 206. You reported that these trucks represent the final units to be produced in two soon-to-be-discontinued cab styles. We regret that we are unable to consider your request, since our authority under section 123 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1410) to grant such exemptions expired in April of this year. Beginning January 1, 1972, the manufacture of any truck not in compliance with the standard will be prohibited. Section 108(a) of the Act provides that "(no) person shall manufacture for sale . . . any motor vehicle . . . manufactured on or after the date any applicable . . . standard takes effect . . . unless it is in conformity with such standard . . ." (15 U.S.C. 1397) The prohibition is enforceable by civil penalties under section 109 (15 U.S.C. 1398) and injunction under section 110 (15 U.S.C. 1349). In addition, in the event that a noncompliance were determined to be a safety-related defect, notification of the defect would have to be furnished under section 113 (15 U.S.C. 1402) to purchaser of the vehicle. LET US KNOW IF WE MAY BE OF FURTHER ASSISTANCE. |
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ID: jan26'95Open Mr. Fredd Scheys Dear Mr. Scheys: This responds to your FAX of January 25, 1995, to John Womack of this Office asking whether the interpretation letter sent to you on November 16, 1992, and confirmation letter sent you on March 8, 1993, remain valid. This confirms that these letters remain valid. We note that the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.) was recodified in July 1994. The correct citation today is 49 U.S.C. Chapter 301 - Motor Vehicle Safety. The first full paragraph of the second page of the November 16, 1992, letter refers to "Title 15, United States Code, section 1397(b)(2)." Under the recodification, the citation has become "Title 49 United States Code, section 30122(b)". Further, the quoted phrase in that paragraph that reads "knowingly rendering inoperative in whole or in part any device of element of design installed in accordance with a Federal motor vehicle safety standard" has been restated to read "knowingly make inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable motor vehicle safety standard." But the meaning remains the same and there is no substantive change in the prohibition. Sincerely, Philip R. Recht Chief Counsel ref:VSA d:1/27/95
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1995 |
ID: nht90-2.44OpenTYPE: Interpretation-NHTSA DATE: May 11, 1990 FROM: Stephen R. Darling -- C.E.T., Presvac Systems (Burlington) Limited TO: NHTSA TITLE: Re 49CRF575 - "Vehicle Owners Manual" ATTACHMT: Attached to letter dated 5-31-90 from S.P. Wood to S. Nishibori (Part 575.6); Also attached to Federal Register, 49 CFR Part 575, (11-27-89 Edition), pages 48745-48749 (text omitted); Also attached to letter dated 10-1-90 from P.J. Rice to S.R. Darling (A36; Std. 567; Std. 568) TEXT: Upon reviewing the recent publication of "Trailer/Body Builder", I noticed the article concerning manufactures statement in owners manual for N.H.T.S.A. notification in case of vehicle defects, as covered in 49CFR575. As a Liquid Cargo Vessel Trailer manufacturer, we acknowledge our obligations in complying with this regulation by September 1, 1990. However, in our other area of manufacturing, namely fabricating and installing Liquid Cargo Tanks onto existing or modified truck chassis, we question our obligations. Could you please advise us of our obligations, if any with regards to 49CFR575 and our truck mounted cargo vessels. Thanking you in advance; we remain, Yours very truly |
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ID: 77-1.19OpenTYPE: INTERPRETATION-NHTSA DATE: 02/08/77 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Emilio Noriega TITLE: FMVSS INTERPRETATION TEXT: This responds to your November 3, 1976, question whether Standard No. 121, Air Brake Systems, prohibits the installation in a towing vehicle of a service brake control that is designed to permit separate, sequential, or simultaneous actuation of the service brake systems of the towing vehicle and any towed vehicle. Assuming that the valve for the towing vehicle represents a "split" service brake system as specified in S5.7 of Standard No. 121, such a service brake control design would not conflict with the Standard's requirements. Of course, the actual compliance of any vehicle with Standard No. 121 depends on the actual installation and performance of the system as well as its design. I would like to note that the agency is not endorsing the service brake control in question by the issuance of this interpretation letter. In fact, the agency is unsure about the effect the control may have on safe braking in a panic situation. Any test information that you or a vehicle manufacturer may care to provide would be appreciated. |
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ID: nht91-1.24OpenDATE: January 15, 1991 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Michael L. Hayes TITLE: None ATTACHMT: Attached to letter dated 7-12-90 from Michael L. Hayes to General Curry, NHTSA; Also attached to letter dated 7-12-90 from Michael L. Hayes to James Gilkey (OCC 5046) TEXT: This responds to your letter to NHTSA's enforcement office and to your telephone conversations with Ms. Fujita of my staff, about the application of Safety Standard 213, Child Restraint Systems, to "transport incubators." Your letter and enclosures indicate that "transport incubator" refers to an incubator that is mounted on a collapsible stand with wheels. The incubator is typically used on an ambulance or helicopter to transfer a neonate from one medical facility to another, or between sites within a facility. The issue raised by your letter is whether Standard 213 applies to transport incubators. We believe the answer is no, because a transport incubator is not an item of "motor vehicle equipment." Our agency has the authority under the National Traffic and Motor Vehicle Safety Act (copy enclosed) to regulate the manufacture and sale of new motor vehicles and items of motor vehicle equipment. Section 102(4) of the Safety Act defines, in relevant part, the term "motor vehicle equipment" as: any system, part, or component of a motor vehicle as originally manufactured or any similar part or component manufactured or sold for replacement or improvement of such system, part, or component or as any accessory, or addition to the motor vehicle... According to the manufacturer of the incubator, whom we contacted for information about the product, the incubator is sold to hospitals, and not to vehicle manufacturers for inclusion in new vehicles. Based on this information, a transport incubator is not a "system, part, or component of a motor vehicle as originally manufactured." Since there is no system, part or component similar to the incubator installed in or on a motor vehicle at the time of its delivery to the first purchaser and since there is no such system, part or component which is original equipment, the incubator is not sold as a replacement or improvement of original equipment. The incubator also does not appear to be an "accessory . . . to the motor vehicle." In determining whether an item of equipment is considered an accessory, NHTSA applies two criteria. The first criterion is whether a substantial portion of the expected use of the item are related to the operation or maintenance of motor vehicles. We determine the expected use by considering product advertising, product labeling, and the type of store that retails the product, as well as available information about the actual use of the product. The second criterion is whether the product is intended to be used principally by ordinary users of motor vehicles. Items normally used by professional vehicle repair and maintenance personnel would not meet this second criterion. If the product satisfies both criteria, the product is considered to be an "accessory" and thus is subject to the provisions of the Safety Act. Applying these criteria to the incubator, we are uncertain whether a substantial portion of the exBpected use of the incubator is related to motor vehicle (ambulance) operation. We are unsure because we lack information about the extent of the non-motor vehicle uses of the incubator. However, regardless of our conclusion about the first criterion, we conclude that the incubator does not satisfy the second one (which is directed to the nature of the likely users of the product). The incubator would not be used by ordinary vehicle owners. Instead, the incubator is intended for use by professional medical personnel only. Since at least one of the criteria is not satisfied, the transport incubator is not an accessory. The Food and Drug Administration has the authority to regulate medical "devices." We suggest that you address your concerns about transport incubators to that agency. I hope this information is helpful. |
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ID: nht93-7.7OpenDATE: October 1, 1993 Est. FROM: Bob Carver TITLE: None ATTACHMT: Attached to letter dated 11/22/93 from John Womack to Bob Carver (A41; Part 571; Std. 217) TEXT: I'm an engineer at Wayne Wheeled Vehicles, a commercial and school bus manufacturing company. My job here is to see ensure compliance to FMVSS 217, effective May 1994. I have a question for you in which I need an official ruling concerning FMVSS 217 S5.5.3(c): Each opening for a required emergency exit shall be outlined around its outside perimeter with a minimum 3 centimeters wide retroreflective tape, either red, white, or yellow in color, that when tested under the conditions specified in S6.1 of 571.131 meets the criteria specified in Table 1. If an emergency roof exit is required, is it necessary to outline it with the retroreflective tape even though it is not visible unless the bus is tilted on its side? Also, Charles Hott at NHTSA said that the width requirement will be revised to 1 inch. Can you confirm this? Thanks in advance for your prompt consideration and assistance concerning this matter. |
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.