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: aiam5036OpenMr. Eugene Welker 774 Harbor Island Clearwater, FL 34630; Mr. Eugene Welker 774 Harbor Island Clearwater FL 34630; "Dear Mr. Welker: This responds to your letter about a mirror syste designed to improve a driver's view of areas behind a motor vehicle. You explained that a 35' vertical post would be bolted near a vehicle's rear bumper. This would result in a mirror being located a few inches above the top rear window stop light and facing forward at a 45 angle. You asked whether such a device would be legal. The following discussion and the enclosed information sheet, 'Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment,' explain your responsibility under NHTSA's regulation. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not approve, endorse, or certify motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act ('Safety Act'), the manufacturer is responsible for certifying that its vehicles or equipment comply with applicable Federal motor vehicle safety standards. The Safety Act requires that these safety standards establish minimum levels of performance for vehicles or equipment. Once the performance level has been established, vehicle or equipment manufacturers are free to choose any means they wish to achieve the required level of performance. NHTSA has exercised its authority to establish performance requirements for new vehicles in Standard No. 111, Rearview Mirrors (49 CFR 571.111, copy enclosed). Standard No. 111 establishes performance and location requirements for rearview mirrors installed in any new vehicle. This means that the vehicle manufacturer must certify that each vehicle it manufactures complies with the specified requirements. Standard No. 111 requires that passenger cars be equipped with an inside rearview mirror and a driver's side outside rearview mirror that provide the field-of-view specified in S5.1.1. A passenger's side outside rearview mirror is required in situations where the inside rearview mirror does not provide the specified field-of-view. Additional requirements for other vehicle types are set forth in S6, S7, and S8. No provision in the Standard specifies requirements for a mirror that attaches to the vehicle's rear bumper. Accordingly, a mirror like yours would not be prohibited from being installed on any vehicle by the current requirements in Standard No. 111. Accordingly such a mirror would be permitted, but only as a supplement to the required mirrors. In installing the mirror, one must take care to avoid obscuring the vehicle's lighting devices, including the center highmounted stop lamps (CHMSL). Please be aware that NHTSA does not regulate vehicles while they are in use. The American Association of Motor Vehicle Administrators, 4600 Washington Blvd, Arlington, VA 22203 may be able to advise you about the laws of the individual States related to the use of equipment such as your own. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, 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"; |
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ID: aiam1075OpenMr. John White, Michelin Tire Corporation, Technical Division, 2500 Marcus Avenue, Lake Success, NY 11040; Mr. John White Michelin Tire Corporation Technical Division 2500 Marcus Avenue Lake Success NY 11040; Dear Mr. White: This is to confirm your conversation with Mr. Schmeltzer of this offic in which he informed you that the Regrooved Tire regulation (49 CFR Part 569) does not prohibit the use of branding to meet its labeling requirements. the language in section 569.9 which requires the word 'regroovable' to be 'molded into or onto' tires designed for regrooving was intended to include any method, such as branding, that would leave the required information sunk into or raised upon the tire surface.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3048OpenHonorable Daniel K. Akaka, 415 Cannon Building, House of Representatives, Washington, DC 20515, Attention: Mr. Pat McGarey; Honorable Daniel K. Akaka 415 Cannon Building House of Representatives Washington DC 20515 Attention: Mr. Pat McGarey; Dear Mr. Akaka: This responds to your June 21, 1979, telephone request asking ho automobile dealers can determine when they must sell school buses as opposed to regular vans.; The key factors in making this determination are the purpose for whic the vehicle will be used and the passenger carrying capacity of the vehicle. The National Highway Traffic Safety Administration (NHTSA) issued the school bus safety standards in response to the Motor Vehicle and Schoolbus Safety Amendments of 1974 (Pub. L. 93-492). In defining 'schoolbus', Congress drew upon NHTSA's definition of 'bus', i.e., any motor vehicle, including a van, designed to carry more than 10 persons. Congress stated that the term 'schoolbus' means 'a passenger motor vehicle which is designed to carry more than 10 passengers ... and which the Secretary determines is likely to be significantly used for the purpose of transporting ... students to or from school or events related to such schools.' The NHTSA concluded from this mandate that any vehicle that is a bus and will be used on a regular and recurring basis to transport school children must comply with school bus safety standards. To effect this conclusion, the agency issued a definition of 'schoolbus' which is 'a bus that is sold or introduced in interstate commerce, for purposes that include carrying students to or from school or related events....'; The effect of the 1974 amendments and the agency's definition is t require any new bus that is sold to transport school children on a regular basis to comply with the safety standards. Compliance is required whether a bus is used regularly to transport students 100 percent of the time or whether it regularly transports students only 10 percent of the time while otherwise transporting adults.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4277OpenMr. David A. White, Senior Safety Engineer, Grumman Olson, Post Office Box 2005, Sturgis, MI 49091; Mr. David A. White Senior Safety Engineer Grumman Olson Post Office Box 2005 Sturgis MI 49091; Dear Mr. White: This letter responds to your inquiry of November 17, 1986, asking thi agency to approve an alternate location for the certification label of a light duty truck your company intends to manufacture for the United States Post Office. Section 567.4 of the National Highway Traffic Safety Administration (NHTSA) regulations requires that a motor vehicle manufacturer affix a certification label to each vehicle it makes, and permits the manufacturer to place the label in any one of the places set out in that provision. If none of those locations is practicable, S567.4 directs the manufacturer to suggest an alternate place to affix the label, and to ask our approval for that alternative.; You explain in your letter that in the circumstances you describe, th S567.4 locations are impractical. First, you explain, the vehicle's sliding doors make the hinge pillar and door latch post and edge too small and irregularly shaped for a label. Second, if your company places the label on the inside of the sliding door, opening the door would hide the label. Third, you assert that the instrument panel is too small for a label.; You enclose a drawing to illustrate where your company intends to plac the certification label. According to your description, the certification label will be placed on a fixed panel behind the driver, and between the cab and the load compartment. This panel is one part of a three piece assembly of which the remaining two components are a center sliding door and a second fixed panel. You state that a person can see the certification label from the driver's area without moving any vehicle item.; In directing a manufacture to put its certification label in thos places set out in S567.4, NHTSA's purpose is to make these labels easy to see and read. Based on the information you supplied, the agency determines that for this particular design, installing the certification label as your company proposes will facilitate seeing and reading the label, while placing the label as specified in S567.4 may not be practicable or might interfere with those activities. Therefore, on the condition that your company's label complies in all other respects with S567.4, NHTSA grants your request to install the certification label on the forward side of the left hand bulkhead fixed panel.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1425OpenMr. Jim Lang, L and R Enterprises, P.O. Box 2201, Wichita Falls, Texas 76307; Mr. Jim Lang L and R Enterprises P.O. Box 2201 Wichita Falls Texas 76307; Dear Mr. Lang: This responds to your February 15, 1974, letter asking whether you installation of spotlights through the left A-pillar of passenger cars is subject to Standards 201 and 216.; Standard 201 does not apply to the instrument panel area on th driver's side from the left door to a longitudinal plane 3-1/4 inches to the right of the steering wheel. The left A pillar is within this excluded area.; Your drilling operation may effect roof strength an I have enclosed copy of Standard 216, our standard on roof crush resistance. Under the National Traffic and Motor Vehicle Safety Act of 1966, it is the responsibility of the person who manufactures or alters a vehicle to determine whether his vehicle meets the requirements.; Your business is subject to these requirements, however, only if yo qualify as an alterer of motor vehicles under 49 CFR 567.7, which is enclosed. The mounting of a spotlight by drilling the A-pillar is a 'non-readily attachable' alteration. Such an alteration would be subject to the S567.7 requirement only if you mount it 'before the first purchase of the vehicle in good faith for purposes other than resale.'; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3418OpenMr. John Y Yonezawa, Tokai Rubber Industries, Ltd., 3600, Kita Toyama, Komaki City, Aichi Pref. 485, Japan; Mr. John Y Yonezawa Tokai Rubber Industries Ltd. 3600 Kita Toyama Komaki City Aichi Pref. 485 Japan; Dear Mr. Yonezawa: This responds to your recent letter regarding several new kinds o plastic vacuum brake hoses that you plan to manufacture. The plastic brake hoses are flexible nylon tubes for use in a vacuum braking system. You indicate that these hoses cannot comply with several provision of Safety Standard No. 106, and ask whether the plastic hoses could qualify as 'vacuum tubing connectors.'; Safety Standard No. 106 (49 CFR 571.106) specifies performance an labeling requirements for brake hose, which is defined in the standard as:; >>>a flexible conduit, other than a vacuum tubing connector manufactured for use in a brake system to transmit or contain the fluid pressure or vacuum used to apply force to a vehicle's brakes.'<<<; Since the nylon tubes which you plan to manufacture will transmit th vacuum used to apply force to a vehicle's brakes, the tubes would qualify as 'brake hose' under this definition and would be subject to all requirements of Safety Standard No. 106. Moreover, it appears that the nylon tubes would not qualify as 'vacuum tubing connectors,' which are excepted from compliance with the standard in the definition of brake hose. Section 4 of Safety Standard No. 106 defines 'vacuum tubing connector' as:; >>>a flexible conduit of vacuum that (i) connects metal tubing to meta tubing in a brake system, (ii) is attached without end fittings, and (iii) when installed, has an unsupported length less than the total length of those portions that cover the metal tubing.'<<<; According to the illustrated drawings included in your letter, th nylon flexible tubes with which you are concerned would have an unsupported length which is greater than the total length of those portions that cover metal tubing. Therefore, the nylon tubes would not qualify as 'vacuum tubing connectors' under subsection (iii) of the above definition. The purpose of the definition is to except from compliance with the standard only those vacuum connectors that have unsupported lengths short enough that they will not sag or deflect because of their own weight. While your nylon tubes may be sturdy enough to meet this intended purpose, as the definition is currently written, the tubes cannot be considered vacuum tubing connectors.; If, as your letter indicates, the nylon brake hose does not comply wit all requirements of Safety Standard No. 106, you would not be permitted to sell it in the United States. You may wish to petition the agency to amend Standard No. 106 to establish separate performance requirements specifically designed for nylon vacuum tubing such as that produced by Tokai. I am enclosing a copy of the procedures which explain how you can file a petition, in case you are interested.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4627OpenMr. L.T. Mitchell, Specification Engineer Thomas Built Buses, Inc. P.O. Box 2450 1408 Courtesy Road High Point, N.C. 27261; Mr. L.T. Mitchell Specification Engineer Thomas Built Buses Inc. P.O. Box 2450 1408 Courtesy Road High Point N.C. 27261; "Dear Mr. Mitchell: This responds to your letter asking us to reasses our previous interpretations of Standard No. 217, Bus Window Retention and Release (49 CFR /571.217). Before turning to the substance of your letter, I would like to apologize for the regrettable delay in this response. You asked us to reassess a December 20, 1984 letter to Mr. Melvin Smith regarding school buses. Mr. Smith had, among other things, asked for an interpretation of the concluding sentence of S5.4.2.1(b) of Standard No. 217. Section S5.4.2.1(b) requires side emergency doors installed in a school bus with a gross vehicle weight rating of more than 10,000 pounds to have an opening that is at least 45 inches high and 24 inches wide when the side door is extended. The final sentence of S5.4.2.1(b) reads: 'A vertical transverse plane tangent to the rear-most point of a seat back shall pass through the forward edge of a side emergency door.' Mr. Smith had asked how much, if any, forward and/or rearward variation from perfect coincidence of the plane and door edge were permissible. We responded that no variation from the explicit requirements of the standard is permissible. Your letter stated that a requirement for an exact coincidence of the plane and door edge 'opens the door to impossible manufacturing requirements,' and is 'an extremely difficult goal to meet.' You stated that requiring an exact relationship between a part of the seat and the door will require multiple seat installation adjustments, bending the seat, or deforming the seat padding. To avoid such burdens, you asked if the agency would consider setting tolerances for the coincidence of the points expressed in this provision. You proposed the following interpretation of the requirement for coincidence of the plane and door edge: 1. A seat back may not intrude backward into the door opening through the transverse plane coincident with the leading edge of the door opening. 2. A seat back may be located ahead of this transverse plane by no more than three-quarters of an inch, plus or minus three-quarters of an inch, or within but no more than, one and one-half inches ahead of the transverse plane coincident with the leading edge of the door opening. It would be helpful to set forth some background information to fully explain why NHTSA cannot issue an intepretation along the lines you have suggested. Section 103 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1392, the Safety Act) specifies that NHTSA shall establish by order appropriate safety standards and that the Administrative Procedure Act shall apply to all orders establishing, amending, or revoking a safety standard. The Administrative Procedure Act generally requires agencies to publish a notice setting forth the proposed change to a safety standard, and allow the public to comment thereon, before the agency can adopt any change to the established safety standard. Please note that the Safety Act requires public notice and comment only when adopting orders that establish, amend, or revoke a safety standard. Interpretations are not subject to the requirements for public notice and comment, because interpretations do not add, delete, or change any requirements established in a safety standard. Instead, intepretations explain how the requirements established in safety standards or the Safety Act apply to particular vehicles or equipment, or otherwise clarify the meaning of the established requirements. In this case, the meaning of the requirement in Standard No. 217 that 'a vertical transverse plane tangent to the rear-most point of a seat back shall pass through the forward edge of a side emergency door' is clear. This language clearly and unequivocally requires an exact coincidence of the location of the seat back and the forward edge of a side emergency door. There is no way that we can interpret this language in accordance with your suggestion, i.e., that the seat back shall be located no more than 1 and 1/2 inches forward of the forward edge of the emergency door. Your letter suggested a change to the requirements of Standard No. 217, not a clarification of those requirements. As explained above, the only way by which we can change those requirements is to initiate rulemaking and give the public notice of and the opportunity to comment on the proposed change. Hence, your letter asking for an interpretation would have been more properly filed as a petition for rulemaking, pursuant to the provisions of 49 CFR Part 552. Ordinarily, we would simply notify you of your right to file such a petition and take no further action unless and until you decided to file such a petition. In this case, however, the delay in this response may have conveyed the erroneous impression that NHTSA would provide a substantive response to your request in this interpretation. To ensure that your request receives a response addressing its merits, we will treat your letter as a petition for rulemaking filed under Part 552. We will notify you of our response to the petition as soon as we have completed our review of it. Sincerely, Stephen P. Wood Acting Chief Counsel"; |
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ID: aiam4430OpenRobert L. Ripley, President Knaack Manufacturing Co. 420 East Terra Cotta Avenue Crystal Lake, IL 60014; Robert L. Ripley President Knaack Manufacturing Co. 420 East Terra Cotta Avenue Crystal Lake IL 60014; Dear Mr. Ripley: This is a response to your letter asking this agenc to review three product catalogs you submitted with your letter, and tell you whether your company is required to furnish information pursuant to 49 CFR Part 566, Manufacturer Identification. Based on the information you supplied with your letter, your company is required to file information under Part 566 for the warning devices shown in one of the catalogs, but not for any of the other items shown in the three catalogs. As specified in the Application section of Part 566 (/566.3), Part 566 applies to (1) all manufacturers of motor vehicles and (2) manufacturers of motor vehicle equipment, other than tires, to which a safety standard applies. The only item advertised in the three catalogs that is motor vehicle equipment to which a safety standard applies is the 'Safety Reflector Kit' shown on page 6 of the catalog entitled 'weather guard For Full-Size and Mini Vans.' These devices are subject to Standard 125, Warning Devices (49 CFR /571.125). Accordingly, your company, as the manufacturer of these devices, must furnish the information specified in /566.5 within the time period specified in /566.6. I hope you find this information helpful. If you have further questions, please contact Joan F. Tilghman of my staff at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1632OpenMr. Zenjiro Hase,Toyoda Gosei Co., Ltd.,9, 1-chome, Nishiyabushitacho,Nishiku, Nagoya, Japan; Mr. Zenjiro Hase Toyoda Gosei Co. Ltd. 9 1-chome Nishiyabushitacho Nishiku Nagoya Japan; Dear Mr. Hase:#I would like to clarify our letter to you of August 21 1974, concerning the use of bands on brake hose assemblies before and after March 1, 1975. I have enclosed copies of your to us and our response.#When our letter stated that we agreed with your interpretation, we did not intend to say that it is permissible to place the label band on brake hose assemblies prior to March 1, 1975. The use of the DOT symbol on these assemblies would constitute a false and misleading certification in violation of S108(a) (3) of the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. S1397(a) (3)). This is because the DOT label would suggest compliance with regulations which are not yet effective.#In the event that our August 21, 1974, letter caused your company to manufacture any assemblies with bands, please contact me as soon as possible.#Yours truly,Richard B. Dyson,Acting Chief Counsel; |
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ID: aiam0920OpenMr. R. B. Smith, Finance Manager, Bluefield Mack Trucks, Inc., 536 Bluefield Avenue, Bluefield, West VA 2470l; Mr. R. B. Smith Finance Manager Bluefield Mack Trucks Inc. 536 Bluefield Avenue Bluefield West VA 2470l; Mr. R. B. Smith: This is in reply to your letter of November 17, 1972, requestin information on alteration, and installation of fifth wheels, on new trucks.; Persons who install fifth wheels on new trucks are generally considere to be 'final-stage manufacturers' under NHTSA Certification regulations, and are required to certify that vehicles on which they install the fifth wheel conform to applicable Federal standards. The NHTSA has recently proposed requirements regarding persons who alter completed vehicles, and a copy of this proposal is enclosed.; Copies of NHTSA requirements maybe obtained as indicated on th enclosure, 'Where to Obtain Motor Vehicle Safety Standards and Regulations.' The regulations regarding the certification of motor vehicles are found at Parts 567 and 568 of Title 49 of the Code of Federal Regulations, (Item 1) and of the volume, 'Federal Motor Vehicle Safety Standards and Regulations' (Item 3).; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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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.