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: nht68-2.6OpenDATE: 05/14/68 FROM: AUTHOR UNAVAILABLE; David A. Fay; NHTSA TO: White Motor Corporation TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of April 16, 1968, to Mr. Lowell K. Bridwell, Administrator, Federal Highway Administration, requesting a clarification of the electrical circuity arrangements that may be used to meet the requirements of paragraph S3.4.3 of Motor Vehicle Safety Standard No. 108. Truck-tractors wired in accordance with your customers' orders stating, "the brown trailer circuit shall be connected to the headlamp switch and the black trailer circuit shall be energized through a seperate switch," will meet the requirements of paragraph 53.4.3, provided the trailer circuits conform to SAE Standard J560a. With this circuitry, your responsibility as a truck-tractor manufacturer would be fulfilled, regardless of the number of trailers that are towed by the truck-tractor. Thank you for writing. |
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ID: 2403yOpen Mr. Patrick S. Baran Dear Mr. Baran: This is in reply to your letter to Taylor Vinson of this Office, with respect to "D.O.T. guidelines for tail light brightness" with respect to a "brake light for the back of a motor cycle helmet." I regret the delay in responding. The Department has no authority to "approve" or "disapprove" items of equipment, but we can provide guidance on the relationship of equipment to the Federal motor vehicle safety standards. I enclose a copy of a l982 interpretation with respect to a similar device, a headlamp intended for installation on a motorcycle helmet. It also represents our views with respect to your device. I enclose also a copy of SAE Standard J586c Stop Lamps, which our Rulemaking office promised you. We note that you use the term "tail light" and "brake light" interchangeably. In seeking State guidance you should be clear as to whether your device indicates the presence of the cyclist (taillamp), or the application of the brakes of the motorcycle (stop lamp), or both. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosure ref:VSA#l08#2l8 d:4/9/90 |
1990 |
ID: 19548.ztvOpenHerr Tilman Spingler Dear Herr Spingler: This is in reply to your fax of February 3, 1999, asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108. You state that Figures 15-1 and 15-2, Figures 17-1 and 17-2, and Figures 28-1 and 28-1 show a position 10U-90U for a lower beam headlamp with a maximum intensity of 125 cd. In your view, it is not clear whether, for compliance testing, that means a scan on the vertical line from 10U to 90U or a scan of an area from e.g., 45L to 45R and from 10U to 90U. Each of the Figures you reference specify a maximum of 125 candela for test points 10U-90U. The Figures do not state where in space from left to right to locate the vertical line, and thus, they do not specify that a line is to be measured. It follows that the only description of a set of test points is that of the entire area from 90L to 90R and 10U to 90U, i.e., an area from the extreme left of the test point grid to the extreme right of the test point grid, with an elevation of from 10U to 90U. Sincerely, |
1999 |
ID: 18756.ztvOpenMr. Hardy Huber Dear Mr. Huber This is in reply to your letter of September 9, 1998, to the agency asking "whether mopeds are required to have a speedometer, and, if the answer is yes, does the speedometer [have] to be lighted." The agency has not adopted the term "moped" in regulating two-wheeled motor vehicles. However, a motorcycle with 5 horsepower or less is called a "motor driven cycle," and we believe that this definition encompasses mopeds. The many Federal motor vehicle safety standards that apply to "motorcycles" will also apply to "motor driven cycles" unless an exception is specifically made within the text of the standard. However, this distinction is not important in terms of your questions. Federal Motor Vehicle Safety Standard No. 123, Motorcycle Controls and Displays, does not require motorcycles of any sort to be equipped with a speedometer. However, if a manufacturer chooses to provide a speedometer, Standard No. 123 requires that it be illuminated whenever the headlamp is activated. It also requires that the speedometer be marked "m.p.h," increasing in a clockwise direction. The standard further requires that major graduations and numerals to appear at 10 mph intervals and minor graduations at 5 mph intervals. Sincerely, |
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ID: aiam3606OpenMr. Shizuo Suzuki, Nissan Motor Co., Ltd., Suite 707, 1919 Pennsylvania Avenue, N.W., P.O. Box 57105, Washington, DC 20037; Mr. Shizuo Suzuki Nissan Motor Co. Ltd. Suite 707 1919 Pennsylvania Avenue N.W. P.O. Box 57105 Washington DC 20037; Dear Mr. Suzuki: This responds to your request for an interpretation concerning Standar No. 101, *Controls and Displays*. You asked several questions concerning informational readout displays. The answers to your questions are as follows.; >>>1. If one type of information is displayed by an electr illuminating device such as a light-emitting diode, can I define this as an IRD?<<<; The answer to this question is yes. Section S4 of Standard No. 10 defines informational readout display as 'a display using light-emitting diodes, liquid crystals, or other electro illuminating devices where *one or more than one type of information* or message may be displayed.' [Emphasis added.] Thus, the type of system you describe comes within Standard No. 101's definition of informational readout display. In reference to the specific wording of your question, I would note that it is the definition in the standard, rather than a particular characterization by the manufacturer, that is determinative as to whether a display is an informational readout display.; >>>2. Do you think that the description 'other electro illuminatin device' includes normal electric bulbs?<<<; The answer to this question is no. The requirements applicable t informational readout displays are an exception to the usual requirements for displays, which ordinarily use normal electric bulbs. The preamble to the final rule establishing the requirements of the present Standard No. 101 explained that the reason for the exception was to 'permit the continued development of informational readout displays.' 43 FR 27541, June 26, 1978. This was necessary since current technology does not enable manufacturers to produce informational readout displays which can exhibit symbols (as opposed to words) or certain colors. Thus, while section S5.2.3 of Standard No. 101 makes the use of certain symbols and colors mandatory for traditional displays, the use of symbols and colors is optional for informational readout displays.; If 'other electro illuminating device' was interpreted to includ normal electric bulbs, traditional displays would come within the definition of informational readout display. Such an interpretation would render meaningless Standard No. 101's requirements for the mandatory use of certain symbols and colors for displays. It is thus clear that the term 'other electro illuminating device' does not include normal electric bulbs. Rather, the term was included within the definition of informational readout display, along with light-emitting diodes and liquid crystals, to avoid preventing the use of new electronic technology other than light-emitting diodes and liquid crystals.; Your third and fourth questions both contemplate that the answer t your second question is yes, rather than no. In reference to your question as to why the agency amended Standard No. 101 to permit the use of green as an alternative to blue or blue-green for the headlamp high beam telltale, the reason is that the agency does not interpret the standard's definition of informational readout display to include a mere colored light using light-emitting diode technology. To be an informational readout display, it must include information in the form of words or symbols. Since such a colored light is not an informational readout display, it must meet the color requirements of Standard No. 101. On February 1, 1982, the agency published a notice in the *Federal Register* (47 FR 4541) which proposed, among other things, an interpretive amendment to the definition of informational readout display to make that point clear. We have enclosed a copy of that notice for your convenience.; Your fourth question suggests that the definition of informationa readout display should be interpreted to include only displays providing more than one type of information. As explained in the answer to your first question, such an interpretation would be inconsistent with the wording of the standard's definition of informational readout display. The agency recognizes, however, that it is likely that most if not all informational readout displays will include more than one type of information, though it is possible that some manufacturers might use LED or similar technology for displays providing only one type. In any event, the agency is not aware of a need to revise the standard's requirements to exclude displays presenting only one type of information from the definition of informational readout display.; >>>5. According to the current regulation, is it possible to integrat telltales with other instrument displays in an informational readout display?<<<; The light intensity requirements of Standard No. 101 currently preven informational readout displays from being used as telltales. Section 5.3.3 of the standard requires that informational readout displays must have at least two light intensity values, a relatively high one for daytime use and a relatively low one for nighttime use. The same section specifies that the light intensity of telltales shall not be variable. Since it is not possible for an informational readout display to simultaneously meet both requirements, such a display cannot be used as a telltale.; We would note, however, that the notice of proposed rulemaking referre to above proposes an amendment to Standard No. 101 that would permit informational readout displays to be used as telltales. The agency is in the process of analyzing the comments received in response to that notice.; Our answer to your fifth question also covers your sixth question. hope this fully responds to your inquiry.; Sincerely, Frank Berndt, Chief Counsel |
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ID: nht94-4.73OpenTYPE: INTERPRETATION-NHTSA DATE: November 1, 1994 FROM: James D. Murphy, Jr. TO: Recht TITLE: NONE ATTACHMT: Attached to 1/3/95 letter from Philip R. Recht to James D. Murphy, Jr. (A43; Part 571.3(b)); Also attached to 6/11/86 letter from Erika Jones to Terry W. Wager TEXT: Dear Mr. Recht, I am designing a vehicle that I hope to certify as a U.S. street-legal motorcycle. As you can see in the drawing, it actually has 4 wheels, but since the left and right side wheels are elevated off the ground, no more than 2 wheels touch the ground at any one time. There are some rare circumstances where all 4 wheels could touch th e ground at the same time, for an instant, but these require precise undulations in the surface of the road. I would imagine that NHTSA defines "ground" as a flat surface (otherwise, a headlamp might exceed NHTSA's upper height limit when cresting a bum p, or drop below NHTSA's lower height limit when traversing a pothole, etc.). Therefore, I hope that this vehicle will still comply with NHTSA's definition of a "motorcycle". I await your reply. Sincerely, James D. Murphy Jr. P.S. You can call me at home at (303) 350-9449; any time. Be sure to ask for James Jr. (Drawing omitted.) |
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ID: nht90-2.12OpenTYPE: Interpretation-NHTSA DATE: April 9, 1990 FROM: Stephen P. Wood -- Acting Chief Counsel., NHTSA TO: Patrick S. Baran -- I.D.E.A. TITLE: None ATTACHMT: Attached to letter dated 11-21-89 To Taylor Vinson and From Patrick S. Baran; Also attached to letter dated 8-2-82 To William R. Harris, Jr. and From Frank Berndt; Attachment SAEJ586c not included. TEXT: This is in reply to your letter to Taylor Vinson of this office, with respect to "D.O.T. guidelines for tail light brightness" with respect to a "brake light for the back of a motor cycle helmet. I regret the delay in responding. The Department has no authority to "approve" or "disapprove items of equipment, but we can provide guidance on the relationship of equipment to the Federal motor vehicle safety standards. I enclose a copy of a 1982 interpretation with respect to a simila r device, a headlamp intended for installation on a motorcycle helmet. It also represents our views with respect to your device. I enclose also a copy of SAE Standard J586c Stop Lamps, which our Rulemaking office promised you. We note that you use the term "tail light" and "brake light" interchangeably. In seeking State guidance you should be clear as to whether your device indicates the presence of the cyclist (taillamp), or the application of the brakes of the motorcycle (st op lamp), or both. |
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ID: 07-005005asOpenJames A. Haigh, Vice President Technical Specifications & Application Development Transpec Worldwide 7205 Sterling Ponds Court Sterling Hts., MI 48312 Dear Mr. Haigh: This responds to your letter regarding whether your product, the Transpec Merge Alert, is permissible under Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, Reflective Devices, and Associated Equipment. Specifically, the Merge Alert is an LED (light emitting diode) device that mounts on the rear of a transit bus, and alternatively flashes in amber lights the word Merging, as well as a Yield sign or an arrow. As discussed below, we do not believe that such a device would be permitted under FMVSS No. 108 if installed as original equipment on a motor vehicle. Furthermore, we believe that it would be a violation of 49 U.S.C. 30122 if the Merge Alert were installed by a manufacturer, dealer, distributor, or motor vehicle repair business. By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue FMVSSs that set performance requirements for new motor vehicles and items of motor vehicle equipment (see 49 U.S.C. Chapter 301). NHTSA does not provide approvals of motor vehicles or motor vehicle equipment. Instead, manufacturers are required to self-certify that their products conform to all applicable safety standards that are in effect on the date of manufacture. NHTSA selects a sampling of new vehicles and equipment each year to determine their compliance with applicable FMVSSs. If our testing or examination reveals an apparent noncompliance, we may require the manufacturer to remedy the noncompliance, and may initiate an enforcement proceeding if necessary to ensure that the manufacturer takes appropriate action. New motor vehicles are subject to the requirements in Standard No. 108 regarding flashing lamps. The question of which lamps are permitted to flash on a vehicle is addressed in paragraph S5.5.10 of FMVSS No. 108. The relevant provision states: The wiring requirements for lighting equipment in use are: (b) Headlamps and side marker lamps may be wired to flash for signaling purposes; In general, flashing lamps are prohibited on vehicles under S5.5.10(d), unless they fall into one of the exceptions listed in S5.5.10(a)-(c). Because the Merge Alert does not fall into any of the lamp categories covered in sections (a)-(c),[1] it is subject to the general prohibition on flashing lamps of S5.5.10(d). Therefore, the Merge Alert could not be installed on transit buses as an item of original equipment or installed on a vehicle by its manufacturer or dealer prior to the initial sale of the vehicle for a purpose other than resale, as it would be a violation of Standard No. 108. Also, S5.1.3 of Standard No. 108 prohibits the addition of equipment on a vehicle if it impairs the effectiveness of lighting equipment required by Standard No. 108. As we have explained to you in previous letters,[2] while there are limited exceptions, we interpret the standard as generally prohibiting electronic message boards because they have the potential of impairing the effectiveness of required lighting. The primary concern is that such devices can distract other drivers sharing the roadway from understanding and responding to the lighting devices required by Standard No. 108. For example, given that your product would be mounted on the rear of a transit bus, it could distract other drivers attention from the required turn signals. While we have recognized a limited exception for school buses, i.e., we defer to the States with respect to the narrow issue of prescribing or prohibiting electronic message boards (including flashing message boards) on school buses, we do not recognize such an exception for transit buses.[3] Also, non-standard signal lamps are generally prohibited by this provision due to the potential to cause confusion. If sold as aftermarket equipment, the Merge Alert would be treated differently. Paragraph S3, Application, of FMVSS No. 108, defines the type of equipment and vehicles that Standard No. 108 applies to. Part (c) of that paragraph applies to [l]amps, reflective devices, and associated equipment for replacement of like equipment on vehicles to which this standard applies. [emphasis added] Because the Merge Alert is an auxiliary lamp that does not replace a like item of motor vehicle equipment, Standard No. 108 is not applicable. Therefore, the requirements of Standard No. 108 would not prohibit the sale of the Merge Alert as aftermarket equipment. However, Federal restrictions would still exist with respect to the installation of the Merge Alert. Under 49 U.S.C. 30122, if an item of equipment is installed by a "manufacturer, dealer, distributor, or motor vehicle repair business," that equipment as installed must not "make inoperative" any of the required safety equipment. As NHTSA has stated in previous interpretations, if an item of motor vehicle equipment impairs the effectiveness of lamps required by Standard No. 108, we consider that to have made the lighting system inoperative, and therefore the installation of that equipment would be a violation of 30122 if performed by a manufacturer, dealer, distributor, or motor vehicle repair business. Therefore, it would be a violation of 30122 for any of these entities to install the Merge Alert on vehicles other than transit buses, even if it was purchased as aftermarket equipment. We note that 30122 applies only to manufacturers, dealers, distributors, and motor vehicle repair businesses. Therefore, if an electronic message board, such as the Merge Alert, is installed by a vehicle owner, without assistance from a manufacturer, distributor, dealer, or motor vehicle repair business, the owner is not violating Federal law if (s)he installs it and uses it. Furthermore, States regulate auxiliary lighting equipment in various ways. We suggest that you contact State agencies to ascertain the legal status of the Merge Alert with regard to State regulation. If you have any further questions, please contact Ari Scott of my staff at (202) 366-2992. Sincerely yours, Anthony M. Cooke Chief Counsel Enclosure ref:108 d.4/8/08 [1] See also our discussion below of flashing message boards on school buses. [2] These letters are available on NHTSAs website at http://isearch.nhtsa.gov/. [3] We note that we do not interpret Standard No. 108 as prohibiting signs on the front of new transit buses showing the destination, although the standard does limit the color of the lamps for such signs. See our October 19, 2006 interpretation to New Flyer, also available at http://isearch.nhtsa.gov/. |
2008 |
ID: 19222.ztvOpenMr. Edward L. Patterson, Sr. Dear Mr. Patterson: We are replying to your letter of November 24, 1998, to Taylor Vinson of this Office, asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices, and Associated Equipment. S7.8.2 of Standard No. 108 allows the installation of protective covers for headlamp aiming adjusters, "removable without the use of tools." You wish to manufacture a design to provide a locking feature. The design "would require only a slight rotating movement to lock." You "propose placing an indentation or hole in the cover, which would allow either a `key' or `coin' be used in order to accomplish this movement." You ask whether "the use of a coin or key, as proposed, be in violation." The use of a key or coin to complete the locking movement would not result in a noncompliance with S7.8.2, but your letter implies that their use is also required for the cover to be removed. As we informed Ford Motor Company on February 12, 1998 (copy of letter enclosed), we consider an ignition key to be a "tool." If a tool is needed to remove a protective cover, then S7.8.2 has not been met. Similarly, we would consider a coin to be a "tool" when used for the purpose of removing the cover. If you have any questions, you may phone Taylor Vinson (202-366-5263). Sincerely, |
1999 |
ID: nht89-3.36OpenTYPE: INTERPRETATION-NHTSA DATE: NOVEMBER 14, 1989 FROM: TRACEY POWELL -- LEGISLATIVE COORDINATOR, GOVERNMENT RELATIONS, AMERICAN MOTORCYCLIST ASSOCIATION TO: STEPHEN WOOD, CHIEF COUNSEL -- NHTSA TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 2/5/90 FROM S. WOOD, NHTSA, TO T. POWELL, AMERICAN MOTORCYCLIST ASSOCIATION; [REDBOOK A35; VSA 103(D); STD. 108] TEXT: The AMA recently completed a study to see how many states have complied with 49 CFR @ 571.108 permitting modulating headlights for motorcycles. We believe modulating headlights should be allowed in every state to help prevent accidents. I was informed that you might find the results of our study of interest. Responses to our recent mailing to a representative in each state indicate that 37 states and the District of Columbia allow the use of modulating headlights either by the passage of legislation or by virtue of not being prohibited by law. Iowa, Miss issippi, Oklahoma, Utah and West Virginia remain unclear even after follow up calls. Although the 1985 ruling clearly recognizes the difference between modulating and flashing lights, Florida, Hawaii, Kansas, Kentucky, Maine, Maryland, Massachusetts and Rhode Island continue to prohibit the use of modulating headlights based on the possibility that a motorcycle with a modulating headlamp might be perceived as an emergency vehicle since flashing lights are generally reserved for emergency vehicles. I have enclosed a response from Maryland indicating their acknowledgment of NHTSA's ruling and intentional disregard for compliance. We would appreciate your assistance in attaining uniform recognition of the legal use of modulating headlights throug hout the United States as approved in 49 CFR @ 571.108. ENC. |
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.