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: GF005903OpenMr. Mark Jagow Dear Mr. Jagow: This is in response to your June 1, 2005, letter in which you ask about certain tire marking requirements in Federal Motor Vehicle Safety Standard (FMVSS) No. 119, New pneumatic tires for vehicles other than passenger cars. Specifically, you ask if you are required to mark the maximum single load rating on tires intended to be used exclusively in tandem. Our answer is yes. S6.5(d) of FMVSS No. 119 requires that the truck tires be marked on each sidewall with, among other things, the maximum load rating and corresponding inflation pressure for the particular tire. This information must be "shown as follows":
Different labeling requirements thus apply depending on whether tires are rated for "single and dual load" or "only for single load".We interpret this provision to require all tires to be rated and marked in one of these two manners; i.e., it is not permissible to mark tires as rated only for dual load. Thus, truck tires rated for dual load applications, including those produced solely for tandem use, must also be labeled with the maximum single load rating in addition to the dual load rating. This is because the tires intended for tandem use could nevertheless be purchased and installed in single application. We believe there is a safety benefit in informing vehicle operators who may use your tires in a way that you did not intend; i.e., in a single application, that the load ratings are different when the tires are not installed in tandem. I hope you find this information helpful. If you have further questions, you may contact Mr. George Feygin of my staff at (202) 366-2992. Sincerely, Stephen P. Wood ref:119 |
2005 |
ID: nht74-5.30OpenDATE: 04/03/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: MAZDA TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 8, 1974, which requests a review of your new accelerator system to determine compliance with Standard No. 124, "Accelerator Control Systems." The NHTSA does not provide a technical review of a manufacturer's product nor certify that a particular design meets the requirements of a standard. That is the manufacturer's responsibility. We will interpret or clarify the meaning of the standard in response to specific questions. We understand your question to be whether two springs surrounding a spring guide and separated by a washer meet the stipulation in S5.1 of Standard No. 124 for ". . . at least two sources of energy . . ." This arrangement of springs would be considered "two sources of energy" within the meaning of the standard. As you requested, the technical description has been held confidential as a "trade secret" and we are returning it to you herewith. ENC. |
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ID: nht88-3.30OpenTYPE: INTERPRETATION-NHTSA DATE: SEPTEMBER 1, 1988 FROM: W. E. BALDWIN PRESIDENT, K-R INDUSTRIES TO: ERIKA Z. JONES -- CHIEF COUNCIL, NHTSA ATTACHMT: MEMO DATED 11-03-88, TO W. E. BALDWIN, FROM ERIKA Z. JONES, STD. 108 TEXT: This is a follow-up of a letter sent you on August 3, 1988 which you forwarded to Mr. Finkelstein of NHTSA. As we interpret Standard S4.1, our product meets all of the requirements except, possibly, S4.5.11(e), requiring that "all other lamps shall be wired to be steady burning. Our improvement consists of a lamp containing 5 bulbs, where each bulb is illu minated in sequential order. The time between each lamp illumination is less than 250ms, providing a steady photometric value, meeting S4.1.1.41(c). The red lens of the lamp is steadily illuminated, with the illusinated area moveing in a back and forth motion. We feel that, since NHTSA has already tested and validated the use of a high mounted break lamp, any additional testing that would be conducted would only determine any improvement in fatal accident statistics. We are not questioning the necessity of the high mounted break lamp. We are offering what we think is a improvement on the lamp, without disturbing present NHTSA standards. In order for for us to determine if it would necessitate petitioning for a Rule change, a Administration interpretatio n of S4.5.11(e) is requested. Simply put, would Rule S4.5.11(e) cover a steadily illuminated light source that moves? Thank you for your interest in this matter. I remain |
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ID: 2894oOpen Mr. Earl Dahl Dear Mr. Dahl: This responds to your letter of June 1, 1988, seeking an interpretation of 49 CFR Part 574, Tire Identification and Recordkeeping. Specifically, you asked whether Goodyear could engrave its mold for the Tire Identification Number with a style of characters that was not specifically authorized in the Notes following Figure 1 of 574.5. Note 1 to Figure 1 of Part 574 specifies only four different print types which may be used for the DOT symbol and tire identification number. The style of print that you wish to use is not one of these designated styles. Nevertheless, Note 4 to Figure 1 states that other print types will be permitted if approved by the National Highway Transportation Safety Administration (NHTSA). The agency has examined the print type shown in the diagram attached to your letter and has no objections to your company printing the required information in the print type you submitted. You should be aware that in the final rule establishing Part 574 (35 FR 17257, November 10, 1970), NHTSA explained that the reason for specifying only four print types which would be acceptable without advance agency approval was to ensure that the information would be easily readable by all persons. The print type that you submitted is easily readable and thus satisfies our concerns in that regard. Accordingly, NHTSA approves your print type. Sincerely,
Erika Z. Jones Chief Counsel ref:574 d:8/26/88 |
1988 |
ID: 2900yyOpen Mr. Chris Lawrence Dear Mr. Lawrence: This is in reply to your letter to Dr. Burgett of this agency. Though dated January 5, 1991, we did not receive it until March 7. With respect to your wish to produce an electronic sign board for installation in the rear window area, or on the rear, of a passenger car, I enclose a copy of an interpretation of this Office dated August 17, l989, regarding such a device. Although the interpretation is restricted to an interior-mounted electronic sign board, our conclusion would not be changed were the device to be mounted on the outside of the rear of the vehicle. In that location, and as an item of original equipment, we believe that it would impair the effectiveness of the required rear lighting equipment by its potential to distract following drivers from the signals sent by the rear lamps when they and the sign board are operated simultaneously. Although the considerations for aftermarket devices are expressed differently, as explained in the August l989 letter, the potential for distraction would appear to create a partial inoperability of the rear lamps within the meaning of the prohibition. Sincerely,
Paul Jackson Rice Chief Counsel Enclosure ref:l08#VSA d:3/2l/9l |
1970 |
ID: 7196Open Mr. Gonshiro Miyoshi Dear Mr. Miyoshi: This responds to your letter of April 6, 1992, asking for an interpretation of Standard No. 108. With respect to a headlamp system consisting of two lamps, each containing two light sources, you have asked "Is it permissible to have the bulb center of the lower beam lower than that of the upper beam (maximum height difference is 10mm) if they are arranged horizontally?" Paragraph S7.5(d)(2) specifies the manner in which "the lower and upper beams of a headlamp system consisting of two lamps, each containing either one or two light sources, shall be provided . . ." In such headlamps where each light source provides a beam, the lower beam is provided "by the outboard light source (or upper one if arranged vertically)," and the upper beam is provided "by the inboard light source (or the lower one if arranged vertically)." Although the standard could be presumed to contemplate that two light sources within a headlamp would be located on the same horizontal or vertical plane, there is no specific requirement for light source placement. Because the difference in the horizontal mounting planes for bulb centers in your design is only 10mm, this difference is not sufficient to conclude that the light sources are vertically arranged, thus requiring that the lower beam bulb center be the "upper" one, or on a plane that is higher. However, for your design to be permissible, the lower beam in this essentially horizontal array must be provided by the outboard light source in the headlamps as specified in S7.5(d)(2). Sincerely,
Paul Jackson Rice Chief Counsel ref:108 d:5/8/92 |
1992 |
ID: nht92-7.9OpenDATE: May 8, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Gonshiro Miyoshi -- Manager, Design Administration Dept., Technical Division Ichikoh Industries, Inc. TITLE: None ATTACHMT: Attached to letter dated 4/6/92 from Gonshiro Miyoshi to Paul J. Rice (OCC 7196) TEXT: This responds to your letter of April 6, 1992, asking for an interpretation of Standard No. 108. With respect to headlamp system consisting of two lamps, each containing two light sources, you have asked "Is it permissible to have the bulb center of the lower beam lower than that of the upper beam (maximum height difference is 10mm) if they are arranged horizontally?" Paragraph S7.5(d)(2) specifies the manner in which "the lower and upper beams of a headlamp system consisting of two lamps, each containing either one or two light sources, shall be provided . . ." In such headlamps where each light source provides a beam, the lower beam is provided "by the outboard light source (or upper one if arranged vertically)," and the upper beam is provided "by the inboard light source (or the lower one if arranged vertically)." Although the standard could be presumed to contemplate that two light sources within a headlamp would be located on the same horizontal or vertical plane, there is no specific requirement for light source placement. Because the difference in the horizontal mounting planes for bulb centers in your design is only 10mm, this difference is not sufficient to conclude that the light sources are vertically arranged, thus requiring that the lower beam bulb center be the "upper" one, or on a plane that is higher. However, for your design to be permissible, the lower beam in this essentially horizontal array must be provided by the outboard light source in the headlamps as specified in S7.5(d)(2). |
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ID: nht72-1.16OpenDATE: 05/31/72 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: The General Tire & Rubber Company TITLE: FMVSS INTERPRETATION TEXT: In response to your letter of May 1, 1972, we would consider a tire with a cord carcass angle of 85 degrees to be within the definition of "radial ply tire" as that term is defined in Motor Vehicle Safety Standard No. 109. |
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ID: nht68-3.35OpenDATE: 05/07/68 FROM: AUTHOR UNAVAILABLE; Robert M. O'Mahoney; NHTSA TO: Heiskell; Donelson; Adams; Williams & Wall TITLE: FMVSR INTERPRETATION TEXT: Mr. Bridwell has asked that I reply to your letter of April 9, 1968. Enclosed for your information is a copy of the chassis-cab ruling and regulation issued December 29, 1967. Under the terms of the ruling and regulation and the National Traffic and Motor Vehicle Safety Act of 1966, when a truck body manufacturer assembles the truck body to a chassis-cab he is responsible for certification only if the completed vehicle is delivered to a dealer or distributor. The body manufacturer assembling the body to the chassis-cab would, however, be responsible for the vehicle's compliance with the lighting standard if not previously met by the chassis-cab manufacturer. Moreover if the addition of the body affects the chassis-cabs previous compliance with standards the body manufacturer would be responsible for compliance. With regard to bodies mounted on chassis-cabs manufactured prior to January 1, 1968 compliance and certification is not required. However, the body, if manufactured on or after January 1, 1968, would have to contain glazing that complies with Standard No. 205 because the body is manufactured for use on motor vehicles and as such must meet any applicable equipment standards. |
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ID: 2862yyOpen AIR MAIL Mr. A. Kling Hamadbik, Ltd 16, Beit Alfa St. Tel-Aviv 67219 Israel Dear Mr. Kling: This responds to your inquiry about the color coding requirements in section S5.1.14 of Federal motor vehicle safety standard No. 116, Motor vehicle brake fluids. (49 CFR 571.116). After noting that DOT 3 and DOT 4 brake fluid must be colorless to amber, you asked what is the color coding range for amber. As explained below, the agency has decided not to specify a numerical or chromatic "range" for the color coding requirements. Instead, the appropriate method for determining compliance to the color coding requirements is through visual inspection. The purpose of the color coding requirements is to permit easy identification of fluids before they are placed in a vehicle, in order to prevent the mixing of an incompatible fluid in a braking system. At one time, the National Highway Traffic Safety Administration (NHTSA) had proposed color requirements defined in terms of millimicrons. (38 FR 32142, November 21, 1973). However, when the agency later determined that visual inspection for color compliance was adequate, the proposed wavelength bands were deleted. (39 FR 30353, August 22, 1974) In a subsequent notice, the agency explained that The specifications for fluid colors are intended to refer to color ranges as generally interpreted in daylight by persons of normal color vision. No color coordinates are proposed, since the fluids may change color in storage or in use (without detriment to the performance of the fluids). (40 FR 56928, December 5, 1975) Thus, the generally interpreted meaning for "amber" (which is defined as "yellowish-brown" by the Random House Dictionary of the English Language) should be used to determine if a brake fluid complies with the color coding requirements for DOT 3 and DOT 4 brake fluid. I hope this information is helpful. If you have any further questions, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely,
Paul Jackson Rice Chief Counsel ref:ll6 d:3/8/9l |
2009 |
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.