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: nht76-3.5OpenDATE: 04/13/76 FROM: STEPHEN P. WOOD FOR FRANK A. BERNDT -- NHTSA COPYEE: BUREAU OF MOTOR CARRIER SAFETY TITLE: FMVSS INTERPRETATION TEXT: I am writing in response to your March 22, 1976, telephone conversation with Mark Schwimmer of this office concerning the treatment of plastic fuel tanks under Federal Motor Vehicle Safety Standard No. 301-75, Fuel System Integrity. As Mr. Schwimmer explained, the National Highway Traffic Safety Administration has issued no safety standards that apply directly to fuel tanks. Standard No. 301-75, which applies to entire vehicles, specifies fuel spillage requirements for barrier crash and rollover tests, but does not include a flame envelopment test. In addition to passenger cars and school buses, the vehicles that are subject to the standard are multipurpose passenger vehicles, trucks, and buses with a Gross Vehicle Weight Rating of 10,000 pounds or less. Standard No. 301-75 applies to new vehicles. In addition, the Federal Highway Administration's Bureau of Motor Carrier Safety has established requirements for certain vehicles in use in interstate commerce. I understand that a fuel tank flame envelopment test is among these. For information concerning such a test, you should communicate with that agency. For your convenience, a copy of Standard No. 301-75 is enclosed. |
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ID: nht74-3.32OpenDATE: 08/30/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Private Truck Council of America, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letters of July 25 and August 26, 1974, requesting information on NHTSA regulations applicable to regrooved tires. You ask whether companies leasing trucks to other companies may equip the trucks with regrooved tires, and what tire standards apply. The recent court decision regarding regrooved tires (NAMBO v. Volpe 483 F. 2d 1294 (D.C. Cir. 1973), Cert. denied, -- U.S. -- (1974)) held that under the National Traffic and Motor Vehicle Safety Act the NHTSA could permit only the sale of regrooved tires. Consequently, the leasing of regrooved tires is now prohibited, as is any other introduction of them into interstate commerce other than by a sale. The NHTSA recently amended its regrooved tire regulations to conform to this Court opinion. We do not construe the opinion to prohibit the leasing of trucks equipped with regrooved tires. The regulation applies only to the manner in which the tires themselves are obtained. The standards applicable to regrooved tires are found in the Regrooved Tire regulations (49 CFR Part 569). Regroovable tires manufactured after March 1, 1975, must also conform to Motor Vehicle Safety Standard No. 119. |
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ID: nht73-3.13OpenDATE: 01/22/73 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Wesbar Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of January 3, 1973, to Mr. Schneider concerning Motor Vehicle Safety Standard No. 108. Your first question is whether the standard requires items of lighting equipment to be marked according to SAE Standard J759a. The answer is no. A manufacturer, at his option, may mark equipment items with the symbol DOT as a certification of compliance with Standard No. 108. Standard No. 108 neither prohibits nor requires other marking of equipment. The NHTSA proposed in 1972 that equipment be marked in a manner somewhat similar to J759a but no definitive action has been taken on the proposal. You also asked whether a clearance lamp could be mounted at 45 degrees to serve the functions of both a clearance and side marker lamp, and whether it must bear the SAE designation "PC" indicating its combination function. Your understanding is correct, that a combination lamp mounted at 45 degrees is permissible if it is successfully tested at that mounting angle for conformance to both clearance and side marker requirements. The designation "PC" is not a current requirement of Standard No. 108 but has been proposed as the required marking symbol in the rulemaking action referred to earlier. |
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ID: 77-4.41OpenTYPE: INTERPRETATION-NHTSA DATE: 11/29/77 FROM: AUTHOR UNAVAILABLE; R. L. Carter; NHTSA TO: General Motors Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of June 3, 1977, to Ms. Joan Claybrook, requesting an interpretation of whether the release action of your "c-ring" seat belt latch mechanism qualifies as a push button action as specified in paragraph S7.2(c) of Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection. Your efforts to improve the comfort and convenience of belt systems thereby increasing the likelihood that they will be used is to be commended. I must point out, however, that the primary purpose of the requirement in paragraph S7.2(c) is to standardize the release method of all seat belts. This reduces the likelihood that occupants will become confused as to how to release a belt in a strange car or in an emergency situation. We have reviewed the operation of your "c-ring" and conclude that the action necessary to release the mechanism does not constitute push botton action. However, incorporation of a push botton release, similar to the design being used in Saab automobiles, would bring your "c-ring" into conformance with S7.2(c) and permit its use. |
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ID: 77-5.16OpenTYPE: INTERPRETATION-NHTSA DATE: 12/26/77 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Wayne Corporation TITLE: FMVSS INTERPRETATION TEXT: This responds to your oral request to Roger Tilton of my staff for the reasons that the National Highway Traffic Safety Administration (NHTSA) exempted buses with gross vehicle weight ratings of 10,000 pounds or less from the requirements of Standard No. 221, School Bus Body Joint Strength. As you know, the NHTSA promulgated the joint strength standard to prevent injuries resulting from the impact of children with the sharp protruding edges of body panel sheets that become unfastened in school bus accidents. This problem, according to the information available to the agency, was particularly acute with respect to large school buses. The agency has no similar data indicating that the joint severance problem is a major factor contributing to injuries in accidents involving smaller school buses. Accordingly, the agency exempted those vehicles from the requirements. Should the NHTSA discover in the future that such problems exist with respect to smaller buses, it would consider extending the requirements to them. I am enclosing a copy of our last notice on Standard No. 221 that fully outlines our reasons for exempting smaller school buses. |
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ID: nht75-1.4OpenDATE: 02/07/75 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Fiat - Research and Development TITLE: FMVSS INTERPRETATION TEXT: FEB 7 1975 N40-30 TWH Mr. Alberto Negro, Director Fiat Research & Development Parklane Towers West One Parklane Boulevard Dearborn, Michigan 48126 Dear Mr. Negro: This responds to your December 30, 1974, question whether the requirement of S5.3.2 of Standard No. 105-75, Hydraulic brake systems, would be satisfied by the use of a 4- to 8-second activation of the brake indicator lamp, activated when the ignition switch is placed in the "on" position. S5.3.2. requires: S5.3.2 All indicator lamps shall be activated as a check of lamp function either when the ignition (start) witch is turned to the "on", (run) position when the engine is not running, or when the ignition (start) switch is in a position between "on" (run) and "start" that is designated by the manufacturer as a check position. A 4- to 8-second activation when the ignition switch is placed in the "on" position as a check of brake indicator lamp function would satisfy the requirements of S5.3.2. Yours truly, Richard B. Dyson Acting Chief Counsel |
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ID: nht75-2.23OpenDATE: 12/23/75 FROM: AUTHOR UNAVAILABLE; Mark Schwimmer; NHTSA TO: FILE TITLE: FMVSS INTERPRETATION TEXT: SUBJECT: VEHICLE REQUIREMENTS AND STANDARD NO. 119 On December 10, 1975, I received a telephone call from Mr. Dan Warner of Transportation Manufacturing Corporation in New Mexico (505 347-2011), concerning the scope of Standard No. 119. Mr. Warner asked whether the standard required vehicles to be equipped with tires conforming to it. I explained that Standard 119 applies only to tires, while vehicles would be the subject of Standard No. 120. I declined to predict the issue date or effective dates of Standard 120, but assured him that the scheme of effective dates would take into account the realities of production and inventories. Meaning of effective date of Standard No. 119 Attorney Advisor Interps. file On December 1, 1975, I received a telephone call from Mr. Nakajima of Bridgestone Tire Co. (213-320-6030) concerning the meaning of the March 1, 1975, effective date of Standard No. 119. He wanted confirmation that tires, for vehicles other than passenger cars, that were manufactured before that date are not subject to the standard's labeling requirements. I explained that his understanding was correct, citing 49 CFR @ 571.7. Mark Schwimmer |
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ID: nht74-5.18OpenDATE: 03/06/74 FROM: AUTHOR UNAVAILABLE; Robert L. Carter; NHTSA TO: Mobile Auto Glass of Iowa, Inc. COPYEE: MR. HUNTER TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of January 30, 1974, concerning requirements for replacement glazing material in trucks and buses. Glazing materials for use in motor vehicles must comply with the requirements of Federal Motor Vehicle Safety Standard No. 205, Glazing Materials, which incorporates the American National Standards Institute Standard No. Z26.1-1966. Section S6 of Standard No. 205 specifies requirements for certification and marking. Paragraph S6.4 and S6.5 of Standard No. 205 covers the specific question you asked. If you cut a section of glass to which this standard applies, for use in a motor vehicle or comper, you are required to mark that glass in accordance with section 6 of Standard No. Z26.1-1966 and to certify that it complies with the standard in accordance with section 114 of the National Traffic and Motor Vehicle Safety Act. I am enclosing a copy of Standard No. 205, Standard No. Z26.1-1966 and section 114 of the National Traffic and Motor Vehicle Safety Act. If I can be of further assistance, do not hesitate to contact me. 3 ENCLS. |
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ID: nht74-5.35OpenDATE: 04/16/74 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: ITT Semiconductors COPYEE: R. HITCHCOCK; MR. HERLIHY TITLE: FMVSS INTERPRETATION TEXT: This is in response to your March 25, 1974, question whether the belt warning system in 1974 or any future model year passenger car is required to activate if a passenger sits on a pre-buckeled belt in a passenger car whose engine is operating and the driver subsequently places the transmission gear selector in a forward position. In 1974 and 1975 passenger car models, the (nonsequential) warning system would be required to activate in this situation only if the passenger weighed at least 47.3 pounds and the belt was not extended at least four inches from its stowed position, in a warning system based on belt extension. It has been proposed that this requirement be extended one year through the 1976 models and that a new sequential belt warning system may be used at the front seating positions after September 1, 1976. The requirements for the new proposed system are set out in the document you reference, Docket No. 74-14; Notice 1, a copy of which is enclosed. It would require that the seat belt be operated after the passenger has been seated. |
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ID: nht75-4.19OpenDATE: 04/21/75 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Novus, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of March 12, 1975, inquiring as to whether any safety regulation of the National Highway Traffic Safety Administration applies to the "Novus Windshield Repair Kit," manufactured by your firm. An advertising brochure for the product states that the material used in the process "is a special waterproof epoxy that not only fills the fissure in the glass but also bonds the crack surfaces to prevent formation or extension of radial cracks." There is no safety regulation of the National Highway Traffic Safety Administration, nor any other Federal law or regulation, which prohibits the use of such a material or process in the repair of windshields which have previously been installed in vehicles and damaged in use. Using such a material or process in a new windshield which may require repair as the result of damage sustained in shipment could cause the windshield to fail to meet the performance requirement of Motor Vehicle Safety Standard No. 205 (49 CFR 5 571.205) and we would therefore discourage use of the Novus kit on new windshields. Please do not hesitate to contact us if we may be of further assistance. |
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.