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
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ID: nht88-3.7OpenTYPE: INTERPRETATION-NHTSA DATE: 08/16/88 FROM: RICHARD H. SCHULTZ -- AMERICAN PULSE LIGHTS INC TO: ROBERT KNAUFF DESIGN TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 07/24/89 FROM STEPHEN P. WOOD -- NHTSA ROBERT KNAUFF; REDBOOK A33; FMVSS 108; LETTER DATED 06/08/89 FROM ROBERT J. KNAUFF -- APPLIED RESEARCH AND DESIGN INC TO KATHLEEN DEMETER -- DOT; LETTER DATED 12/07/87 FROM RICHARD H. SCHULTZ -- AMERICAN PULSE LIGHTS TO ROBERT J. KNAUFF TEXT: Dear Mr. Knauff: This is an evaluation of your school bus rear warning lamp demonstration with a pop-flash option. I initially expected that we would have a problem with high intensity flash washing out the red lens and appearing white. Technically this is what happens and if you concentrate on it, the flash can appear white. The flash duration however was so brief and when used in concert with red in the cycle did not appear white to me. That should clear one obstacle, as white is prohibited in this type of lamp. Dual day/night intensity should not be necessary as long as you stick with red lamps. You should also not have to restrict the pop to less than every flash, but in any case you will have to locate the discharge bulb so that the parabolic reflector and lens of the host lamp project the energy at very nearly about the H-Y point. Any large amount that occurs down at a level so as to be observed by a passenger car operator less than, let us approximate, 200 feet away would probably be objectionable to some, depending upon a number of factors that I need not go into at this point. Generally, we have a basic concept that a signal is either required or not permitted. This keeps messages clear between vehicle operators. In this case however, I believe that we can consider this option since it is only an appendage modification of an existing warning system. When you clear this modification with the National Highway Traffic Safety Administration compliance office and with the Minnesota Department of Education student transportation office, we would need to have a look at the finished product and your test da ta for purposes of commissioner's authorization or commissioner's approval certification depending upon the marketing approach that is possible and that you wish to take. Sincerely, |
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ID: nht88-3.9OpenTYPE: INTERPRETATION-NHTSA DATE: 08/19/88 FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA TO: DENNIS G. MOORE -- PRESIDENT SIERRA PRODUCTS INC. TITLE: NONE ATTACHMT: LETTER DATED 04/06/88 TO ERIKA Z. JONES FROM DENNIS G MOORE, OCC - 1860 TEXT: Dear Mr. Moore: This is in reply to your letter of April 6, 1988, bringing to our attention the differing definitions of Canada and the United States of "optically combined lamps." The Canadian interpretation of that term appears to prohibit export of your lamps to that country. I have reviewed the materials you enclosed. They indicate that until recently the two countries interpreted the phrase identically. As the then Chief Counsel Frank Berndt advised the Trailer Manufacturer Association on June 18, 1979, "the phrase is not intended to prohibit the installation of two separate bulbs in a single housing and covered by a common lens," and on October 22, 1981, Canada informed you that "The Canadian and U.S.A. federal standards are identical with respect to optical combination ...." However, Canada has undertaken to define the term by regulation in its revised CMVSS No. 108 rather than by interpretation as we have done. Under an amendment adopted in December 1987, a lamp with two separate bulbs in a single housing and covered by a common lens would be "optically combined." Canada believes that this "harmonizes" with the intent of FMVSS No. 108, us consistent with ECE practice, and similar to the definition adopted in J587 by the SAE. You believe that Canada's action is inco nsistent with the "Agreement on Technical Barriers to Trade" between the two countries. It would appear that NHTSA's definition and interpretation of the term is more permissive than that of the authorities you quoted, and that lamps meeting U.S. requirements might be barred from sale in Europe as well as Canada. The issue of whether this situation presents a trade barrier is not one that is properly before this agency. Matters of trade policy, and particularly allegations of trade agreement violations are within the jurisdiction of the United States Trade Representative, who can be contacted at 600 17th Street, NW, Washington, DC 20506 (202-395-3204). However, NHTSA is an active participant in ECE lighting discussions and I shall bring this matter to the attention of the responsible agency personnel. Thank you for bringing this matter to our attention. Sincerely, |
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ID: nht90-3.71OpenTYPE: Interpretation-NHTSA DATE: August 30, 1990 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: S. Watanabe -- General Manager, Automotive Equipment Technical Coordination Dept., Stanley Electric Co., Ltd. TITLE: None ATTACHMT: Attached to letter dated 7-13-90 from S. Watanabe to S.P. Wood TEXT: This responds to your letter of July 13, 1990, requesting an interpretation of how the photometric requirements of FMVSS 108 would apply to a combined taillamp and side marker lamp. Your letter indicates that "the light output of side marker lamp is als o emanated toward the rear of the vehicle mixed with tail lamp light, and similarly, the light output of tail lamp is also emanated toward the side mixed with side marker lamp light." You requested answers to the following two questions. "1) Should the Tail lamp function of this lamp meet the photometric requirements for 2 lighted sections, or 3 lighted sections?" Although NHTSA and the SAE have not defined "lighted section", we understand it to be that portion of a lens that is illuminated, either singly by a single light source, or in common by more than one light source. Your question assumes that the number o f bulbs in your lamp is equal to the number of lighted sections, that is to say, that each bulb illuminates a separate section of the lens. However, in your design, all bulbs contribute, without interruption by a divider or other light-directing feature , to the illumination of the lens. Therefore, we regard your lamp as a single compartment lamp to which the single lighted section requirements of SAE Standard J585e Tail Lamps (Rear Position Lamps), September 1977, apply, even though the illumination i s provided by three light sources. "2) Should the Side marker function of this lamp meet the photometric requirement of SAE J592e by 3 lighted sections or 1 lighted section?" Standard No. 108 also incorporates by reference SAE Standard J592e Clearance, Side Marker, and Identification Lamps, July 1972. Unlike SAE J585e, SAE J592e does not contain different photometric requirements depending on the number of lighted sections. Therefore, we interpret your question as asking whether photometric compliance is determined on the basis of the bulb that is dedicated to that purpose, or by all three bulbs. Because there is no clearly defined side marker lamp other than the portion of the lamp that is visible from the side, compliance should be measured using all three light sources in the lamp. I hope you find this information helpful. |
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ID: nht89-2.38OpenTYPE: INTERPRETATION-NHTSA DATE: 07/21/89 FROM: STEPHEN P. WOOD -- NHTSA TO: Anonymous (confidential) TITLE: NONE TEXT: Dear This is in reply to your letter of June 30, 1989, to John Donaldson of this Office titled "Request for Interpretation", submitted on behalf of your client. You request "that all identifying references to myself, my firm and [my client] in this letter and the responsive letter of interpretation" be deleted. Your request is granted on the basis that it relates to confidential business information and may be withheld under applicable Departmental regulations, 49 CFR Part 512. You describe a lamp system as follows: "The product is a headlamp consisting of a plastic lens and reflector, arc tubes (two each for high and low beam) and electronics for instant start and re-start of the headlamps as well as management of the operating current. A 12 volt connection is supplied for connection of vehicle line voltage". You have asked for a letter "confirming" that this lamp system is designed to conform to the integral beam headlamp requirements of paragraph S7.4 of Federal Motor Vehicle Safety Standard No. 108, "subject only to compliance with the appropriate photomet ric requirements of FMVSS 108." A headlighting system of the nature described must be designed to conform to all the pertinent requirements of S5.5, S7.1, S7.2, and S7.7, as well as S7.4, including mechanical aim and environmental requirements. However, since this headlamp does not us e filaments for converting the electrical energy to light energy, certain configurations of such systems may not conform, because some requirements are predicated upon the existence of filaments (e.g., S5.5.9 and S7.4(f)). If the headlamp you describe m eets all requirements, then it would appear to be an integral beam headlighting system designed to conform to S7.4. Whether the headlamp in fact meets those requirements is for the lamp manufacturer to determine, as it must assure the manufacturer of the vehicle on which it 2 is installed that he may certify compliance of the vehicle with Standard No. 108. Further, the headlamp manufacturer itself must certify compliance of replacement equipment. If the headlamp is incompatible with these requirements and cannot meet them, then it would not appear to be an integral beam system. In that case, rulemaking would be required to accommodate it within the framework of Standard No. 108. Sincerely, |
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ID: nht89-2.76OpenTYPE: INTERPRETATION-NHTSA DATE: 08/23/89 FROM: STEPHEN P. WOOD -- NHTSA ACTING CHIEF COUNSEL TO: TAKAYOSHI CHIKADA -- MANAGER OF AUTOMOTIVE LIGHTING ENGINEERING CONTROL DEPT. STANLEY ELECTRIC CO., LTD. TITLE: NONE ATTACHMT: LETTER DATED 06/16/89 FROM TAKAYOSHI CHIKADA TO RICHARD L. VANIDERSTINE -- NHTSA; RE REVISION OF FMVSS NO 108 [DOCKET NO 85-15 NOTICE 8] TEXT: Dear Mr. Chikada: This is in reply to your letter of June 16, 1989, to Mr. Van Iderstine of this agency, by FAX as you requested. You have asked four questions with respect to the recently amended Federal Motor Vehicle Safety Standard No. 108. We responded to your first two questions in a letter dated June 19 to Mr. Hasegawa of your office. A copy is enclosed for your reference. Since that time, however, in response to a petition by General Motors, we have changed the effective date of parag raph S7.7.5.1(a) to December 1, 1989, with respect to replaceable bulb headlamp systems. A copy of this notice is also enclosed. Your third question is: How should we prove the confirmation to the requirement of S7.7.2.2? We think the combination of Horizontal and Vertical angle within the aim range will be so huge and it is not practicable to test for all combinations. This paragraph applies to headlamps aimed by moving the reflector relative to the lens and headlamp housing, or vice versa. The agency has frequently advised manufacturers that there is no legal requirement that conformance be demonstrated through the t est procedures stated in the standard. While the agency will use those procedures in its compliance testing, the manufacturer may certify compliance with the performance requirements of a standard through engineering studies, computer simulations, mathe matical calculations, or other means intended as an exercise of due care and affording a reasonable basis upon which to certify compliance. Your final question is: It is acceptable to set up initial "O" point of S7.7.5.2(a)(2) not mechanically but photometrically? You may determine the "O" point by whatever means you deem appropriate for the headlighting system, as long as the method achieves a horizontal "O" point that may be used for the purposes of paragraph S7.7.5.2(a)(2), and any other paragraph in which the horizontal "O" mark is required to be determined. In the future, please address your requests for interpretations of Standard No. 108 to this office. Sincerely, ENCLOSURE |
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ID: 22584.ztvOpen Mr. Neil Mardell Dear Mr. Mardell: This is in reply to your letter of January 9, 2001, enclosing documents in support of your request to import and sell your IT (Neighborhood Electric Vehicle) in the United States. We understand that you have filed a Designation of Agent with this Office's General Law Division, and we have delivered the Acceptance of Appointment you enclosed to the appropriate attorney in the Division. Similarly, we have taken your Manufacturer Identification statement and sample compliance label to the appropriate Office in this agency. There was no legal need for you to file the "proof of compliance with the requirements of FMVSS 500" because no approval is needed under the laws of the United States for you to export the vehicle to the United States from Canada. The maximum speed test of the prototype IT resulted in a value of 39.998 km/h, barely beneath the definitional ceiling of 40 km/h for low-speed vehicles. Please note that each production IT must not exceed the definitional ceiling, not just the single prototype vehicle tested. The narrow margin of 0.002 km/h in the test of the prototype IT may not be sufficient to ensure that the maximum speed of production vehicles does not exceed 40 km/h. This is especially critical when the maximum speed of the IT is artificially limited by a programmable motor controller. Component tolerances, adjustments, environments, and manufacturing variables can result in different test results. If you have technical questions about Standard No. 500's test procedure, you may contact John Finneran of our Office of Vehicle Safety Compliance (202-366-0645). Your product literature notes the availability in late 2001 of two light utility versions of the IT. Under 49 CFR 571.3(b), a "low-speed vehicle" is defined in part as a vehicle "other than a truck." A "truck" is, among other things, "a vehicle designed primarily for the transportation of property." The two light utility ITs are designed primarily to carry property and would be trucks. Trucks are not eligible for certification under Standard No. 500 even if their maximum speed does not exceed 40 km/h. Sincerely, John Womack d.3/8/01 |
2001 |
ID: 1985-04.21OpenTYPE: INTERPRETATION-NHTSA DATE: 11/15/85 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: Mr. Leo Kagan TITLE: FMVSS INTERPRETATION TEXT:
Mr. Leo Kagan Director of Marketing Automotive Division Amco Manufacturing Corp. 7425 Fulton Avenue North Hollywood, CA 91605
Dear Mr. Kagan:
This is in reply to your letter of August 19, 1985 to Mr. Vinson of this office requesting an interpretation of Standard No. 108 as it pertains to your design of "a rear deck luggage rack with an approved brake light attached to the crossbar".
Because each passenger car manufactured on or after September 1, 1985, is required to have a center high-mounted stop lamp as original equipment, we shall assume that you wish to produce the luggage rack/center stop lamp as an aftermarket accessory for vehicles manufactured without the lamp before September 1, 1985. The Federal standard does not cover the center high-mounted stop lamp as an aftermarket lamp (except as replacement equipment for original equipment lamps), and there is no Federal prohibition against your marketing this equipment. However, the legality of your design will be determinable under the laws of any State in which a vehicle so equipped is operated.
I hope that this answers your question.
Sincerely, Erika Z. Jones Chief Counsel
August 19, 1985
Taylor Vinson Legal Counsel NHTSA, Room 5219 U.S. Dept. of Transportation 400 7th St. S.W. Washington, D.C. 20590
Mr. Vinson:
In a conversation with Dr. Burdett on August 14, he suggested I write you again to obtain a ruling on supplying a rear deck luggage rack with an approved brake light attached to the crossbar - as seen in the enclosed photos.
We deliberately attached the brake light below the bar - rather than above - to eliminate any possibility of accidentally knocking the light off the bar.
If you have any questions, please call me on 800/423-2353. Will look forward to hearing from you - & many thanks for your help. Sincerely,
AMCO MANUFACTURING CORPORATION Leo Kagan Director of Marketing Automotive Division LK:rt |
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ID: 1985-04.6OpenTYPE: INTERPRETATION-NHTSA DATE: 10/26/85 FROM: AUTHOR UNAVAILABLE; Jeffrey R. Miller; NHTSA TO: Charles Pekow --Editor, Day Care USA TITLE: FMVSS INTERPRETATION TEXT:
Mr. Charles Pekow Editor, Day Care USA 4550 Montgomery Avenue Suite 700-N Bethesda, MD 20814
This is in further response to your July 23, 1985 telephone call to the National Highway Traffic Safety Administration asking whether a Head Start facility is considered a "school" for purposes of determining the applicability of our school bus safety standards. As Ms. Hom informed you, the answer is yes.
Enclosed are copies of two letters from this office addressing this " question. Our December 21, 1977 letter to Mr. James Tydings explains that Head Start facilities are preprimary schools within the scope of the National Traffic and Motor Vehicle Safety Act (as amended by the Motor Vehicle and Schoolbus Safety Amendments of 1974). We have also enclosed a May 10, 1982 letter to Mr. Martin Chauvin of the New York State Department of Transportation. You might be interested in the discussion in the Chauvin letter that distinguishes day care centers from Head Start facilities. I understand that you might be contacting us with further questions regarding our school bus safety standards. We will be happy to assist you.
Sincerely,
Stephen P. Wood Assistant Chief Counsel for Rulemaking
Enclosures
NOA-30
Mr. James Tydings Thomas Built Buses, Inc. 1408 Courtesy Road P. O. Box 2450 High Point, North Carolina 27261
Dear Mr. Tydings:
This responds to your November 11, 1977, letter asking whether Head Start facilities are considered preprimary schools for purposes of applying the Federal school bus safety standards.
The National Highway Traffic Safety Administration (NHTSA) has determined that these facilities are primarily involved with the education of preprimary school children. Thus, the buses used to transport children to and from the Head Start facilities are considered school buses under the National Traffic and Motor Vehicle Safety Act (as amended by the Motor Vehicle and School Bus Safety Amendments of 1974) and must meet all Federal school bus safety standards. Sincerely,
Joseph J. Levin, Jr. Chief Counsel |
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ID: 86-1.11OpenTYPE: INTERPRETATION-NHTSA DATE: 01/24/86 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: G. F. Kirchoff -- Special Project Manager, Morton Thiokol, Inc. TITLE: FMVSS INTERPRETATION TEXT:
G. F. Kirchoff Special Project Manager Morton Thiokol, Inc. 3350 Airport Road Ogden, UT 84405
Thank you for your letter of November 13, 1985, to Stephen Oesch of my staff asking how our standards would affect a diagnostic and sensor warning light for a self-contained airbag system you arc developing. You explained that the system would be mounted in the steering wheel and would have the diagnostic and sensor light located on the steering wheel horn pad.
Your warning light would be affected by Safety Standard No. 208, Occupant Crash Protection, S4.5.2 of the standard requires crash-deployed restraint systems, such as airbag systems, to have an indicator that monitors the readiness of the system, In addition, the indicator must be clearly visible from the driver's seat. Placing your diagnostic and sensor warning light in the center of the horn pad should ensure that it is visible to the driver. If you have any further questions, please let me know. Sincerely,
Erika Z. Jones Chief Counsel
13 November,1985 U200-FY86-060
Mr. Steve Oesch, NOA-32 U. S. Department of Transportation National Highway Traffic Safety Administration 400 Seventh Street, S.W. Washington, D. C. 20590
Dear Mr. Oesch: Subject: Diagnostic and Sensor Light in Horn Pad
Morton Thiokol, Inc. is presently developing a self-contained airbag system for the automobile driver. As such, this system is planned to have a warning light in the steering wheel horn pad. It is an electrical system with the sensor and diagnostics, and capacitor power supply located in the driver module. The warning light for the diagnostics is planned to be either red or green. It would also appear to be desirable from an occupant attention standpoint to locate it on the horn pad.
We wish to insure that the placement of the warning light is in compliance with all NHTSA regulatory requirements and would appreciate your review and position on this. Thank you very much. Sincerely,
G. F. Kirchoff Special Project Manager |
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ID: 86-1.16OpenTYPE: INTERPRETATION-NHTSA DATE: 02/03/86 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: Mr. Donald L. Stephens TITLE: FMVSS INTERPRETATION TEXT:
February 3, 1986 Mr. Donald L. Stephens Paccar Technical Center 1261 Highway 237 Mount Vernon, Washington 98237 Dear Mr. Stephens: This responds to your letter of September 13, 1985, asking two questions regarding the legality of an air brake system which proportions the amount of air brake pressure delivered to the drive axles of a tandem drive tractor. By "proportions", you refer to the reduction of the applied air pressure at all treadle positions in rough proportion to the load carried by the tires. Your first question is whether an air brake system such as the one you described would be legal if it otherwise complies with Standard No. 121, Air Brake Systems, (49 CFR 571.121). You also would like to know if it would be legal for you to remove the front axle limiting valve in the design you propose. By way of background information, this agency does not give approvals of motor vehicles or equipment. The National Traffic and Motor Vehicle Safety Act places the responsibility on the manufacturer to ensure that its vehicles or equipment comply with all applicable requirements. A manufacturer then certifies that its vehicles or equipment comply with all applicable requirements. The following represents our opinion based on the facts provided in your letter. In response to your first question, the NHTSA's regulations do not address the matter of proportioning. Standard No. 121 does not specify the design of brake system components; rather, it establishes a performance level. A brake system which proportions the amount of air brake pressure delivered to the drive axles of a tandem drive tractor is not prohibited if it otherwise meets Standard No. 121. As to your second question, NHTSA regulations do not require nor do they prohibit a vehicle from having a front axle limiting valve. Therefore, vehicles need not have these valves in order to meet our standard and you are not prohibited from removing the front axle limiting valve in the design you propose. In fact, an interim technical report of the NHTSA Heavy Duty Vehicle Brake Research Program, published April, 1985, concluded that automatic front axle limiting valves in many vehicles. significantly degrade straight line performance in the empty mode and on wet surfaces. However, if a vehicle does have an automatic pressure limiting valve, it must meet the test requirements set out in S6.1.8.1 of Standard 121. Sincerely, Original Signed by Erika Z. Jones Chief Counsel |
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.