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: aiam2582OpenMr. Noah Stone, 2620 Equitable Building, Atlanta, GA 30303; Mr. Noah Stone 2620 Equitable Building Atlanta GA 30303; Dear Mr. Stone: This letter is to confirm a telephone conversation you had with Kath DeMeter of this office on May 17, 1977. You asked whether the Federal odometer mileage disclosure statement, required to be executed by 49 CFR Part 580, needed to be a separate piece of paper. The answer is 'no.' The regulation does not require the disclosure to be separate from other documents. If the full information required by section 580.4 can be included, a disclosure on the bill of sale or other document would satisfy the requirements. The only limitation is that it would have to be executed prior to the completion of the sale as required by section 580.4(a) of the regulation.; If you have any further questions, please do not hesitate to write. Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam0415OpenMr. David A. Phelps, Jr., Group Supervisor, Engineering Services, Blue Bird Body Company, Fort Valley, GA 31030; Mr. David A. Phelps Jr. Group Supervisor Engineering Services Blue Bird Body Company Fort Valley GA 31030; Dear Mr. Phelps:#This is in reply to your letter of July 7 askin whether paragraph S4.2 of Standard No. 101 requires labeling of 'a heater water valve near the floor in the driver's area.'#As you know, Standard No. 101 requires identification of heating and air conditioning controls that are manually operable and mounted in a location other than on the floor. Your heater water valve is manually operable and not floor mounted, and it is our opinion that Standard No. 101 requires its identification. This agency published an interpretation on May 4, 1971, copy enclosed (see p. 8297), in response to a query from Ford 'whether controls visible to the driver but not in the normal forward line of sight must be identified.' We replied in the affirmative that although controls may be 'designed to be operable by touch, their function is not clear to an operator unfamiliar with the vehicle in which they are installed, and their identification is necessary.' For the same reason paragraph S4.2 of Standard No. 101 requires identification of your heater water valve control.#Sincerely, Lawrence R. Schneider, Acting Chief Counsel; |
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ID: aiam2428OpenMr. L. T. Mitchell, Jr., Engineering Department, Thomas Built Buses, Inc., 1408 Courtesy Road, P. O. Box 2450, High Point, NC 27261; Mr. L. T. Mitchell Jr. Engineering Department Thomas Built Buses Inc. 1408 Courtesy Road P. O. Box 2450 High Point NC 27261; Dear Mr. Mitchell: This is in response to your letter of September 2, 1976, in which yo ask whether the definition of 'contactable surface' in Standard No. 222, *School Bus Passenger Seating and Crash Protection*, includes areas on the front of the seatback located more than three inches from the top of the seat.; Your interpretation of 'contactable surface' is correct. The standar states in paragraph S4 that only the uppermost three inches of area on the front of the seatback if considered part of the 'contactable surface.' The remainder of the front of the seatback is not considered part of the 'contactable surface' and need not meet the head impact requirements of S5.3.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam4905OpenMr. Wayne Trueman BX-100 International 2550 Appian Way, Suite 211 Pinole, CA 94564; Mr. Wayne Trueman BX-100 International 2550 Appian Way Suite 211 Pinole CA 94564; "Dear Mr. Trueman: This responds to your recent inquiry abou installing your brake equalizer on new school buses and retrofitting this device on used school buses. A brake equalizer is a valve system that proportions the brake pressure between front and rear brakes. After explaining that California law provides that school bus brake systems may be modified only with the written approval of the school bus chassis manufacturer, you asked whether other states have similar requirements about written authorization. You also asked whether there are any special regulations pertaining to school buses that need to be considered prior to installing or retrofitting your product into school bus air brake systems. I regret that we are unable to provide information concerning state requirements in this area. However, you may be able to obtain the information you desire by contacting individual state directors of pupil transportation. I have enclosed a list of those state officials, as published in School Bus Fleet magazine in January 199l. I can, however, explain Federal requirements that are relevant to installing your product in new and used school buses. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Highway Traffic and Motor Vehicle Safety Act (Safety Act), it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with all applicable standards. The following represents our opinion based on the facts provided in your letter. NHTSA does not have any specific regulations about brake equalizers. However, since this device is tied into a vehicle's air brake system, it could affect a vehicle's compliance with FMVSS No. 121, Air Brake Systems. That standard applies to almost all new trucks, buses (including school buses), and trailers equipped with air brake systems. If your brake equalizer is installed as original equipment on a new vehicle, the vehicle manufacturer is required to certify that, with the device installed, the vehicle satisfies the requirements of all applicable safety standards, including FMVSS No. 121. (see 15 U.S.C. 1397(a)(1) and 49 CFR Part 567) If the device is added to a previously certified new motor vehicle prior to its first consumer sale, the person who modifies the vehicle would be an alterer of a previously certified motor vehicle and would be required to certify that, as altered, the vehicle continues to comply with all of the safety standards affected by the alteration. (49 CFR 567.7) If the device is installed on a used vehicle (i.e., retrofitted) by a manufacturer, distributor, dealer, or motor vehicle repair business, the installer would not be required to attach a certification label. However, it would have to make sure that it did not knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard. (15 U.S.C 1397(a)(2)(A)) You may wish to review the Federal Highway Administration's Federal Motor Carrier Safety Regulations, which sets forth inspection and maintenance requirements for commercial motor vehicles, including some school buses. (49 CFR Parts 393 and 396.) I hope this information is helpful. If you have any further questions, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam5617OpenMs. Karey Clock Moriden America, Inc. 915 Western Drive Indianapolis, IN 46241; Ms. Karey Clock Moriden America Inc. 915 Western Drive Indianapolis IN 46241; "Dear Ms. Clock: This responds to your inquiry about testing procedure in Federal Motor Vehicle Safety Standard No. 302, Flammability of Interior Materials. In particular, you asked whether certain materials, which you list as flat woven, double raschel, tricot, and moquette, should be tested by using support wires. The short answer is that during NHTSA compliance testing, support wires may be used in testing any specimen that 'softens or bends at the flaming end so as to cause erratic burning.' However, the agency cannot specify, outside of the context of a compliance test, whether a given type of material falls in this category. By way of background information, NHTSA is authorized to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA does not, however, approve or certify any vehicles or items of equipment. Instead, the Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. You ask about Standard No. 302, which specifies requirements for the flammability resistance of materials in the occupant compartment of new vehicles. Along with specified performance requirements, Standard No. 302 sets forth conditions and procedures under which NHTSA tests materials for compliance with the standard. Section S5.1.3 of the standard states, in relevant part, that The test specimen is inserted between two matching U-shaped frames of metal stock 1-inch wide and 3/8 of an inch high. The interior dimensions of the U-shaped frames are 2 inches wide by 13 inches long. A specimen that softens and bends at the flaming end so as to cause erratic burning is kept horizontal by supports consisting of thin, heat resistant wires, spanning the width of the U-shaped frame under the specimen at 1-inch intervals. A device that may be used for supporting this type of material is an additional U-shaped frame, wider than the U-shaped frame containing the specimen, spanned by 1--mil wires of heat resistant composition at 1-inch intervals, inserted over the bottom U-shaped frame. You ask whether certain specific types of materials could be tested using the supplemental wire described in S5.1.3. The agency uses supplemental wires when there is a reasonable expectation that a test specimen will soften and bend while burning. The agency bases its determination about the likelihood of softening and bending on observations made in previously-conducted compliance tests of the specimen, or on the agency's knowledge of or testing experience with components that are highly similar to a test specimen. However, since a decision to use wires is made only in the context of compliance testing, we regret that we cannot tell you at this time whether support wires will be used to test the materials you listed. Vehicle manufacturers are not required by Standard No. 302 to test the flammability of their vehicles in the manner specified in the standard. The standard only sets the procedure that the agency will use in its compliance testing. Thus, a vehicle manufacturer is not required to use wires only with specimens that are anticipated to soften or bend. However, vehicle manufacturers must exercise due care in certifying that their product will meet Standard No. 302's requirements when tested by NHTSA according to the specified procedures of the standard. Whether a vehicle manufacturer has met that due care standard when using support wires in situations other than those described in Standard No. 302 is a matter that can be determined only in the context of an enforcement proceeding. I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0946OpenMr. F. S. Murley, Administrative Engineer, Oshkosh Truck Corporation, Post Office Box 560, Oshkosh, WI 54901; Mr. F. S. Murley Administrative Engineer Oshkosh Truck Corporation Post Office Box 560 Oshkosh WI 54901; Dear Mr. Murley: This is in reply to your letter of January 4, 1973, in which you as for our confirmation of your interpretation of Part 567 and Part 568 of Title 49 of the Code of Federal Regulations that would place the responsibility for certification on the user in those instances where he is the final-stage manufacturer.; Paragraph 567.5 of Title 49 of the Code of Federal Regulations Requirements for Manufacturers of Vehicles Manufactured in Two or More Stages, specifies that '. . . each final-stage manufacturer, . . . of a vehicle manufactured in two or more stages shall affix to each vehicle a label . . . .' Therefore, end users who are also manufacturers would be required to affix the label.; If you have further questions, we will be pleased to answer them. Sincerely, Francis Armstrong, Director, Office of Standard Enforcement, Motor Vehicle Programs; |
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ID: aiam3669OpenMr. Jack Fazio, Quality Assurance Manager, Safetee Glass Division, Chromalloy, 250 King Manor Drive, King of Prussia, PA 19406; Mr. Jack Fazio Quality Assurance Manager Safetee Glass Division Chromalloy 250 King Manor Drive King of Prussia PA 19406; Dear Mr. Fazio: This responds to your recent letter asking whether it is necessary fo your company to obtain a new glazing DOT number when it transfers production of some of its safety glazing materials to a new plant location.; It is not necessary for you to obtain a new DOT number since the statu of your company is not changing. You indicate that this change only represents a move of production operation from one facility to another. We will note your additional address on our records and nothing further is required.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1654OpenMr. James H. Thomas, 8 North Queen Street, Griest Building, Lancaster, Pennsylvania 17603; Mr. James H. Thomas 8 North Queen Street Griest Building Lancaster Pennsylvania 17603; Dear Mr. Thomas: This is in reply to your letter of September 27,1974, requesting ou position regarding the micro-siping of tires. You also request copies of the government brief in *United States* v. *General Tire*.; The NHTSA does not consider the micro-siping process to be prohibite *per se* when applied to new motor vehicle tires subject to either Motor Vehicle Safety Standard No. 109, 49 CFR S571.109 (applicable to passenger car tires), or Motor Vehicle Safety Standard no. 119, 49 CFR S571.119 (applicable to tires for vehicles other than passenger cars). In the *General Tire* case, the particular tires involved have been micro-siped and were found to have failed certain laboratory wheel tests specified in Standard No. 109. The only issue in the case was General's responsibility for the failure and not whether the tires met the standard. General chose to stipulate that they did not.; This agency has no data on whether micro-siping adversely affects tire's ability to conform to the standards. It is possible that the quality of micro-siping may cause compliance problems. In any event, the agency does not consider micro-siped tires to fail to conform to either standard, unless there is an actual failure to meet the performance tests of the standards.; I have enclosed a copy of the government's brief in the Court o Appeals in the *General Tire* matter. There are other briefs in this litigation, but the agency's position is set forth in this brief and it should be satisfactory for your purposes.; We are pleased to be of assistance. Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3393OpenMr. Leonard A. Fink, Attorney at Law, Friedman and Medalie, 1899 L Street, NW, Washington, DC 20036; Mr. Leonard A. Fink Attorney at Law Friedman and Medalie 1899 L Street NW Washington DC 20036; Dear Mr. Fink: This is in reply to your letter forwarding your firm's vehicl identification numbering system and requesting confirmation that it complies with Federal Motor Vehicle Safety Standard No. 115 - Vehicle identification number.; The National Highway Traffic Safety Administration (NHTSA) does no give advance approval of a manufacturer's compliance with motor vehicle safety standards or regulations, as it is the manufacturer's responsibility under the National Traffic and Motor Vehicle Safety Act to ensure that its vehicles comply with the applicable safety standards. However, my office has reviewed your proposed system. Based on our understanding of the information which you have provided, your system apparently complies with Standard No. 115.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4456OpenMr. J.V. McFadden President MTD Products Inc. P.O. Box 36900 Cleveland, Ohio 44136; Mr. J.V. McFadden President MTD Products Inc. P.O. Box 36900 Cleveland Ohio 44136; Dear Mr. McFadden: This responds to your letter concerning th applicability of Federal or State requirements to a hydraulic logsplitter mounted on a frame carriage equipped with highway high speed wheels and a trailer towing hitch. While we can not answer your question concerning applicable State requirements, we provide the following information on the applicability of Federal motor vehicle safety standards. By way of background information, our agency is authorized, under the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1381 et seq.), to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment, nor do we endorse commercial products. Instead, the Vehicle Safety Act establishes a 'self-certification' process under which each manufacturer is required to certify that its products meet all applicable safety standards. The Vehicle Safety Act prohibits the manufacture or sale of a noncomplying product unless, despite the exercise of due care, the manufacturer doesn't have reason to know that the noncompliance exists. Any vehicle that falls within the statutory definition of the term 'motor vehicle' must comply with all applicable safety standards. Section 102(3) of the Vehicle Safety Act (15 U.S.C. 1391(3)) defines a 'motor vehicle' as any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails. We have interpreted this language as follows. The definition does not include equipment which uses the highways only to move between job sites and which typically spends extended periods of time at a single job site. In this case, the on-highway use of the vehicle is merely incidental, and is not the primary purpose for which the vehicle was manufactured. On the other hand, when a vehicle frequently uses the highway going to and from job sites, and stays at the job site for only a limited time, it is the agency's position that the vehicle in question is a 'motor vehicle' in the statutory sense, since the on-highway use is more than 'incidental'. Notwithstanding the foregoing, a vehicle is not classified as a motor vehicle if it is of such an unusual configuration that it is easily distinguished from normal traffic and it has a top speed of not more than 20 miles per hour. A determination of whether or not a vehicle falls within the definition of motor vehicle is based upon a consideration of all of the above factors. Given the information that you have provided us, it appears that the hydraulic log-splitter is a motor vehicle. From the picture in the brochure, it is clear that the vehicle has an unusual configuration. This alone, however, is not adequate to prevent a determination that the vehicle is a motor vehicle within the meaning of the statute. More important is the fact that the vehicle may make frequent use of the highway, staying at one particular job site a limited amount of time. The provision of highway speed tires indicates the manufacturer's intention to produce a vehicle which is suitable for driving at highway speeds. Because the tow-behind logsplitter is equipped with a trailer tow hitch, we would consider the vehicle a trailer, defined in the agency's regulations as: a motor vehicle with or without motive power, designed for carrying persons or property and for being drawn by another motor vehicle. (See 49 CFR 571.3.) The safety standards which apply to all trailers are Standard No. 108, Lamps, reflective devices, and associated equipment, Standard No. 120, Tire selection and rims for motor vehicles other than passenger cars, and Standard No. 115, Vehicle Identification Number--Basic Requirements. The content requirements for the vehicle identification number are found at Part 565. In addition, if the trailer is equipped with brakes, it must meet Standard No. l06, Brake hoses, Standard No. 116, Motor vehicle brake fluids, and applicable requirements of Standard No. 121, Air brake systems. All of these standards are found in 49 CFR Part 571. We regret the delay in responding to your request. If you have further questions on this matter, please contact us. Sincerely, Erika Z. Jones 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.