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: nht69-1.35OpenDATE: 04/01/69 FROM: AUTHOR UNAVAILABLE; R. M. O'Mahoney; NHTSA TO: European Tire and Rim Technical Organization TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of January 21, 1969, requesting the "actual state of affairs" concerning States requiring a V-1 marking on tires. You are correct in your understanding that the Federal tire standard (No. 109 preempts or supersedes any State regulation applicable to the same aspect of performance. The Federal tire standard does not require tires to be marked with the "V-1" symbol. However, it does not prohibit such marking. Our understanding is that American tire manufacturers have continued marking their product with "V-1" symbol although not required to do so by the Federal standard. |
|
ID: GF003064OpenMr. Christopher H. Willison Dear Mr. Willison: This responds to your letter of April 1, 2004, and subsequent conversations with George Feygin of my staff. You ask a series of questions regarding DOT regulations related to a pressure vessel used for tire inflation located inside a hollow semi-trailer axle. By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards (FMVSSs) that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to certify that their vehicles and equipment meet applicable requirements. There is no FMVSS regulating pressure vessels located in hollow semi-trailer axles as described in your letter. In fact, the agency does not have any regulations covering tire inflation systems for heavy vehicles. However, if your system is tied into the vehicles air braking system, it may affect compliance with other safety standards. Specifically, FMVSS No. 121, Air Brake Systems, may have implications for your product, especially if your device is an integral part of the brake system. We do not have sufficient information about your device to discuss FMVSS No. 121 implications. However, in a previous letter of interpretation (copy attached) we stated that a tire inflation device would not be considered a part of the braking system if it was separated from the vehicles main braking system by a pressure protection valve in such a way that the main braking system would not be affected by a leakage failure in the device. Further, the air supply line between the air supply tank described in your letter and the pressure vessel could be considered a brake hose subject to the requirements of FMVSS No. 106, Brake Hoses. In a previous letter of interpretation, we stated that if a failure of a hose or a supply line would result in a loss of pressure in the brake system, that hose or supply line are subject to the requirements of FMVSS No. 106 (copy enclosed). For your reference, I am enclosing a fact sheet we prepared entitled Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment. I hope this information is helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman Enclosures |
2004 |
ID: 22968.ztvOpenMr. Gene Whitaker Dear Mr. Whitaker: This is in reply to your letter of February 7, 2001, asking whether a "pole-hauling" trailer that you manufacture is exempt from "the Federal regulation that requires . . . reflective tape." You furnished pictures of the trailer with your letter. The regulation to which you refer is Federal Motor Vehicle Safety Standard No. 108. This standard does not apply to "pole trailers" (S3(a) of 49 CFR 571.108). A pole trailer is a trailer "attached to the towing vehicle by means of a reach or pole, or by being boomed or otherwise secured to the towing vehicle, for transporting long or irregularly shaped loads such as poles, pipes, or structural members capable generally of sustaining themselves as beams between the supporting connections" (49 CFR 571.3(b)). Your trailers appear designed to haul trees or logs, which would be long loads within the meaning of the definition of "pole trailer." We have therefore concluded that this trailer is a "pole trailer" and not required to comply with the requirements of Standard No. 108, including the requirements for conspicuity marking. Sincerely, John Womack ref:108 |
2001 |
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: nht94-3.22OpenTYPE: INTERPRETATION-NHTSA DATE: June 6, 1994 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: M. Guy Dorleans -- Valeo Vision TITLE: None ATTACHMT: Attached To Letter Dated 4/20/94 From Guy Dorleans To Mike Perel TEXT: Dear M. Dorleans: This responds to your FAX of April 20, 1994, to Mike Perel of this agency, asking for an interpretation of Standard No. 108. The drawing in your letter depicts a four-lamp headlamp arrangement in which the outermost lamps (lower beam) incorporate HB4 light sources, and the innermost lamps (upper beam), HB3 light sources. In operation, the outermost lamps alone provide the low er beam. However, when the upper beam switch is thrown, all lamps are energized. You ask for confirmation of your interpretation that "outer unit must fulfill table 15a for Low Beam, an (sic) also that inner must fulfill with HB3 alone table 15a High B eam." Paragraph S7.5 of Standard No. 108 specifies requirements for four-lamp replaceable bulb headlamp systems such as the one you describe. The photometrics that apply to such systems are set forth in paragraph S7.5(b): "The photometrics as specified in sub paragraphs (c) through (e) of this paragraph (depicted in Figure 26) . . . ." Because subparagraph (d) applies to a headlamp equipped with dual filament replaceable light sources and Types HB3 and HB4 are single filament sources, the applicable subparagr aph is (e), and, more specifically, the four-headlamp specifications of (e)(3). This will confirm your understanding. Under S7.5(e)(3), the lower beam is to be produced by the outermost lamps and designed to conform to the lower beam requirements of Figure 15; the upper beam by the innermost lamps and designed to conform to the upp er beam requirements of Figure 15. This is confirmed in Figure 26. However, the photometrics of Figure 15A will apply on and after September 1, 1994, (Paragraph S7.1). 2 Simultaneous activation of both upper and lower beams is permitted by S5.5.8 of Standard No. 108 for headlighting systems designed to conform to Figure 15. Later this year, we will amend Standard No. 108 to substitute Figure 15A for Figure 15, effective September 1, 1994. Sincerely, |
|
ID: 11807A.SPWOpen Mr. John Hrabosky Dear Mr. Hrabosky: This responds to your letter of April 9, 1996, addressed to Walter Myers of my staff, in which you ask what "D.O.T. safety standards [do you] need to be aware of" in producing a vehicle you refer to as a "winch trailer." You enclosed pictures of your winch trailer, which can be described as a single-axle enclosed trailer whose dimensions are estimated to be approximately 6 to 8 feet long, 5 feet wide, and 4 feet high. The metal enclosure is equipped with side hatches and a back door that open to provide access to the winch and associated tools and equipment mounted inside. The pictures show the trailer hitched to a pickup truck in preparation for towing. You state that the purpose of the winch trailer is "to aid in utility replacement." You also state that the trailer is equipped with electric brakes, has a gross vehicle weight of approximately 4,000 pounds, and has a tongue weight of approximately 250 pounds. In response to your question about applicable standards, we are enclosing a fact sheet entitled "Federal Requirements for Manufacturers of Trailers," which lists the standards and regulations applicable to trailers. Copies of the listed standards and regulations may be obtained by following the instructions in the enclosed fact sheet entitled "Where to Obtain NHTSA's Safety Standards and Regulations." A copy of the cover of the volume you will need is attached to this fact sheet. The cost of the volume is approximately $40.00. In addition, we are enclosing the following pertinent information for motor vehicle manufacturers: a. Chapter 301 of Title 49, U.S. Code (the statutory provisions under which NHTSA has issued its safety standards and regulations); and b. Fact sheet entitled "Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment." Should you have any further questions or need additional information, feel free to contact this office at the address shown above or at (202) 366-2992, FAX (202) 366-3820. Sincerely,
Samuel J. Dubbin Chief Counsel Enclosures Ref:VSA d:5/9/96
|
1996 |
ID: nht90-2.56OpenTYPE: Interpretation-NHTSA DATE: May 29, 1990 FROM: Edward Kultgen -- Secretary, Bird-Kultgen Ford Volkswagen TO: Stephen P. Wood -- Acting Chief Counsel, NHTSA TITLE: None ATTACHMT: Attached to letter dated 5-10-82 from F. Berndt (Signature by S.P. Wood); Also attached to letter dated 3-27-78 from J.J. Levin, Jr to B. Nanninga (VSA 102(14)); Also attached to letter dated 8-3-77 from J.J. Levin, Jr. to J.L. O'Connell (VSA 1 02(14)); Also attached to letter dated 7-12-77 from J.J. Levin, Jr. to J. Thomason (VSA 102(14)); Also attached to letter dated 9-10-90 from P.J. Rice to E. Kultgen (A36; VSA 108(b)(1); VSA 102(14); Part 571.3) TEXT: We have today received from the Ford Motor Company Central Regional Sales Office a copy of your letter to Sen. Gramm dated May 10, 1990, concerning the sale and/or rental of passenger vans to transport students. While your letter clarified most of the i ssues in this matter faced by those of us with dealer-owned rental companies, it brought up a couple of related questions for which we need answers. First, does Section 108 (b) (1) of the Safety Act, or any other section, apply to the retail sale of used vehicles? For example, we have been approached from time to time by representatives of various small church-related schools seeking to purchase a u sed late-model 15-passenger van, obviously at least in part for the purpose of transporting students on field trips, to extra-cirricular events, etc. Would the sale of such a used vehicle under these circumstances violate the Safety Act? Second, for this purpose, what is the definition of "student"? Four specific groups come immediately to mind: (a)clients of a local MHMR children's developmental learning program; (b)students enrolled in a local community college; (c)church youth group s; and (d)children enrolled in after-school or summer day care programs. There are other similar groups with whom we deal in the course of business, but an answer for these examples should give us sufficient guidance in following the requirements of the statute. I appreciate your attention to these questions, and I hope to hear from you or a member of your staff in the near future. |
|
ID: nht68-3.1OpenDATE: 05/17/68 FROM: AUTHOR UNAVAILABLE; David A. Fay; NHTSA TO: Berliner Motor Corporation TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of April 10, 1968, addressed to Mr. William H. Risteen, concerning the requirement for headlamp dimmer switches as specified in Federal Motor Vehicle Safety Standard No. 108. Paragraph S3.4.1 of Standard No. 108 requires that a means for switching between lower and upper headlamp beams shall be provided in accordance with SAE Recommended Practice J564a or J565a. This general requirement is applicable to all vehicles, including motocycles, that are required, by Standard No. 106, to be equipped with lower and upper bean headlamps, even though SAE Recommended Practice J564a is addressed only to passenger cars. Thank you for writing. |
|
ID: nht71-1.39OpenDATE: 02/18/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Toyo Tire (U.S.A.) Corporation TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of February 2, 1971, to Mr. Casanova concerning Part 574 - Tire Identification and Record Keeping. Adding a group of numbers consisting of three-digits to the tire identification number is not permitted under the regulation because the additional numbers 99:(Illegible Word) be too easily confused with the tire identification number. You are not prohibited, however, from placing the additional three-digit number elsewhere on the tire in an area where it would not be confused with the required tire identification number. Anywhere further than six inches would be far enough to avoid confusion. |
|
ID: nht90-3.54OpenTYPE: INTERPRETATION-NHTSA DATE: August 13, 1990 FROM: Thomas J. Loughran -- V.P. Engineering, The Grote Manufacturing Company TO: General Jerry Ralph Curry -- NHTSA TITLE: None ATTACHMT: Attached to letter dated 9-10-90 from P.J. Rice to T.J. Loughran (A36; Std. 108) TEXT: On December 13, 1989 the Bargman Company requested an opinion regarding a turn signal lamp with a combined reflector. Acting Chief Counsel Stephen P. Wood issued an opinion on February 26, 1990. The opinion used the terms tail lamp and turn signal lamp interchangeably. The result is chaos, as you can see from the attached copy of a release published in an industry magazine. Although I totally disagree with his opinion regarding he suitability of an amber reflector as an auxiliary device on the rear of a vehicle, it is not as disastrous as promulgating the idea that an amber tail lamp is also acceptable. I do not believe th e amber tail lamp was his intent but that has been the effect as a result of a inadvertent use of words. Both of these conditions are a major disappointment to those who take highway safety seriously, first, because of the impairment of highway safety, and second, because the opinion was issued without benefit of review and comment by concerned individuals and organizations. Your review of this condition will be appreciated. (Attached is an article entitled, It's the Law, Rear Amber Reflector, text omitted.) |
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.