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: aiam2393OpenMr. Bing Johnson, 135 Jade Cove Drive, Roswell, GA 30075; Mr. Bing Johnson 135 Jade Cove Drive Roswell GA 30075; Dear Mr. Johnson: This is in response to your letter of August 16, 1976, in which you as about our regulations concerning the modification of 'vans' to make them suitable for camping. The modifications you propose to make include the installation of plumbing, water, electricity, and additional seating.; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. SS 1381 *et seq.) prohibits the manufacture, offer for sale, sale, introduction in interstate commerce or importation of a motor vehicle that does not comply with all applicable standards in effect on the date of its manufacture. This prohibition does not apply (except for importation) after the first purchase of the vehicle in good faith for purposes other than resale. Under these provisions, you are responsible for the compliance of any vehicle that you modify up to and including the time of first purchase for purposes other than resale.; The manufacturer must comply with all applicable safety standard established by the National Highway Traffic Safety Administration (NHTSA). His certification appears on a completed vehicle. It would be your responsibility to ensure that the vehicle continues to comply with all applicable safety standards after your modification. Under Part 567 of our regulations, you must attach a label to the vehicle that states that, as altered, the vehicle continued to conform to the standards.; From the description of the modification you describe, it appears tha you might affect the compliance of the vehicle with the following standards: Standard No. 207, *Seating Systems*, Standard No. 208, *Occupant Crash Protection*, Standard No. 210, *Seat Belt Assembly Anchorages*, and Standard No. 302, *Flammability of Interior Materials*. It should be noted that any additional weight created by your modifications or a change in the distribution of weight could also affect the vehicle's compliance with other safety standards whose test procedures require a barrier crash test.; We also would point out that if you modify a Ford 'Econoline' in al probability you would change the vehicle classification from a truck to a multipurpose passenger vehicle. This should be noted on the certification label that you attach to the vehicle.; I have enclosed an information sheet that explains where you may obtai copies of these regulations.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0761OpenMr. J. Donald Waldman, P.E., President, Resources Applications, Designs & Controls, Inc., 7045 Marcelle Street, Paramount, CA, 90723; Mr. J. Donald Waldman P.E. President Resources Applications Designs & Controls Inc. 7045 Marcelle Street Paramount CA 90723; Dear Mr. Waldman: This is in reply to your letter of June 13, 1972, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' to recreational vehicles. You ask, under paragraph S4.1 of the standard, whether materials not designed to absorb energy on contact by occupants must conform to the standard, and list materials and components which you believe might be within this classification.; Except in the case of the components specifically enumerated in S4.1 components that are designed not to absorb energy on contact by occupants are not subject to the standard. Enumerated components must conform to the standard regardless of whether they are energy-absorbing.; With respect to the materials which you list, whether or not they mus meet the standard depends upon whether they are used in the manufacture of any of the components listed in S4.1, either as surface materials, underlying materials, or padding and cushioning materials. In some cases, consequently, insulating materials such as those you list could fall within the materials that should be tested. In each case the manufacturer must determine whether the material is part of the listed component.; With reference to the components you list, open cabinets and cabine tops would be considered under S4.1 to be compartment shelves and toilets would be considered to be seat backs and seat cushions. Walls would be classified as trim panels. Lavoratories and shower doors are not within the enumerated components.; You also ask, in the case of unitized walls having a depth of 2 inche or more, whether the test should be limited to a section 1/2 inch thick. The thickness of the tested sample depends upon the portion of the component which is tested pursuant to paragraphs S4.2(a), S4.2(b), and S4.2(c). In each case, the portion of the material that is tested is cut to a 1/2 inch thickness when the portion of the material as it appears in the vehicle exceeds that thickness (S5.2.1).; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2388OpenMr. Bing Johnson, 135 Jade Cove Drive, Roswell, Georgia 30075; Mr. Bing Johnson 135 Jade Cove Drive Roswell Georgia 30075; Dear Mr. Johnson: This is in reply to your letter of August 16, 1976 in which you ask about our regulations concerning the modification of 'vans' to make them suitable for camping. The modifications you propose to make include the installation of plumbing, water, electricity, and additional seating.; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. SS 1381 *et seq.*) prohibits the manufacture, offer for sale, sale, introduction in interstate commerce or importation of a motor vehicle that does not comply with all applicable standards in effect on the date of its manufacture. This prohibition does not apply (except for importation) after the first purchase of the vehicle in good faith for purposes other than resale. Under these provisions, you are responsible for the compliance of any vehicle that you modify up to and including the time of first purchase for purposes other than resale.; The manufacturer must comply with all applicable safety standard established by the National Highway Traffic Safety Administration (NHTSA). His certification appears on a completed vehicle. It would be your responsibility to ensure that the vehicle continues to comply with all applicable safety standard after your modifications. Under Part 567 of our regulations, you must attach a label to the vehicle that states that, as altered, the vehicle continued to conform to the standards.; From the description of the modification you describe, it appears tha you might affect the compliance of the vehicle with the following standards: Standard No. 207, *Seating Systems*, Standard No. 208, *Occupant Crash Protection*, Standard No. 210, *Seat Belt Assembly Anchorages*, and Standard No. 302, *Flammability of Interior Materials*. It should be noted that any additional weight created by your modifications or a change in the distribution of weight could also affect the vehicle's compliance with other safety standards whose test procedures required a barrier crash test.; We also would point out that if you modify a Ford 'Econoline' in al probability you would change the vehicle classification from a truck to a multipurpose passenger vehicle. This should be noted on the certification label that you attach to the vehicle. I have enclosed an information sheet that explained where you may obtain copies of these regulations.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2391OpenMr. Bing Johnson, 135 Jade Cove Drive, Roswell, GA 30075; Mr. Bing Johnson 135 Jade Cove Drive Roswell GA 30075; Dear Mr. Johnson: This is in response to your letter of August 16, 1976, in which you as about our regulations concerning the modification of 'vans' to make them suitable for camping. The modifications you propose to make include the installation of plumbing, water, electricity, and additional seating.; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. SS1381 *et seq*.) prohibits the manufacture, offer for sale, sale, introduction in interstate commerce or importation of a motor vehicle that does not comply with all applicable standards in effect on the date of its manufacture. This prohibition does not apply (except for importation) after the first purchase of the vehicle in good faith for purposes other than resale. Under these provisions, you are responsible for the compliance of any vehicle that you modify up to and including the time of first purchase for purposes other than resale.; The manufacturer must comply with all applicable safety standard established by the National Highway Traffic Safety Administration (NHTSA). His certification appears on a completed vehicle. It would be your responsibility to ensure that the vehicle continues to comply with all applicable safety standards after your modifications. Under Part 567 of our regulations, you must attach a label to the vehicle that states that, as altered, the vehicle continued to conform to the standards.; From the description of the modifications you describe, it appears tha you might affect the compliance of the vehicle with the following standards: Standard No. 207, *Seating Systems*, Standard No. 208, *Occupant Crash Protection*, Standard No. 210, *Seat Belt Assembly Anchorages*, and Standard No. 302, *Flammability of Interior Materials*. It should be noted that any additional weight created by your modifications or a change in the distribution of weight could also affect the vehicle's compliance with other safety standards whose test procedures require a barrier crash test.; We also would point out that if you modify a Ford 'Econoline' in al probability you would change the vehicle classification from a truck to a multipurpose passenger vehicle. This should be noted on the certification label that you attach to the vehicle.; I have enclosed an information sheet that explains where you may obtai copies of these regulations.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0933OpenMr. Bernard J. Haynes, Manager, Quality Control, The Stearns & Foster Co., Cincinnati, OH, 45215; Mr. Bernard J. Haynes Manager Quality Control The Stearns & Foster Co. Cincinnati OH 45215; Dear Mr. Haynes: This is in reply to your letter of November 15, 1972, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials', to innerspring mattresses you are going to produce for use in motor homes. You raise four questions in your letter which are restated below.; >>>1. 'Under S4.2 of the Standard, do we test the surface materia only, or is tufting considered bonded, sewed, or mechanically attached to underlying material?'<<<; Paragraph S4.1 of the standard lists mattress covers only, and thi would include the tufting since the tufting is incorporated into mattress covers. Consequently, we would treat the underlying material as separate, and only test mattress covers together with the tufting.; >>>2. 'If it is considered mechanically attached, how do we prepare specimen for test?'<<<; Since only mattress covers in this case must meet the requirements o the standard, the question of the tufting's 'mechanical attachment' to underlying material does not arise. Accordingly, you would prepare test specimens of mattress covers together with the tufting in the manner in which it appears in the vehicle as described in Paragraph S5.2 of the standard.; >>>3. 'The sleeping compartment is without a door and at the rear o both a 22 foot and a 25 foot motor home. Is this area considered in the occupant compartment?'<<<; The occupant compartment of a motor home includes any part designed t be occupied by persons. It would include the sleeping compartment irrespective of whether there is a door separating the sleeping compartment from the driver's compartment.; >>>4. 'Must all the material of the mattress, excluding the innersprin unit, pass the test independently, or is Article C of Section S4.2 about protective padding?'<<<; Paragraph S4.1 of the standard lists mattress covers only. Since S4. only refers to items listed in S4.1, it does not include the mattress stuffing.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2390OpenMr. Bing Johnson, 135 Jade Cove Drive, Roswell, GA 30075; Mr. Bing Johnson 135 Jade Cove Drive Roswell GA 30075; Dear Mr. Johnson: This is in response to your letter of August 16, 1976, in which you as about our regulations concerning the modification of 'vans' to make them suitable for camping. The modifications you propose to make include the installation of plumbing, water, electricity, and additional seating.; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. SS 1381 *et seq*.) prohibits the manufacture, offer for sale, sale, introduction in interstate commerce or importation of a motor vehicle that does not comply with all applicable standards in effect on the date of its manufacture. This prohibition does not apply (except for importation) after the first purchase of the vehicle in good faith for purposes other than resale. Under these provisions, you are responsible for the compliance of any vehicle that you modify up to and including the time of first purchase for purposes other than resale.; The manufacturer must comply with all applicable safety standard established by the National Highway Traffic Safety Administration (NHTSA). His certification appears on a completed vehicle. It would be your responsibility to ensure that the vehicle continues to comply with all applicable safety standards after your modifications. Under Part 567 of our regulations, you must attach a label to the vehicle that states that, as altered, the vehicle continued to conform to the standards.; From the description of the modifications you describe, it appears tha you might affect the compliance of the vehicle with the following standards: Standard No. 207, *Seating Systems*, Standard No. 208, *Occupant Crash Protection*, Standard No. 210, *Seat Belt Assembly Anchorages*, and Standard No. 302, *Flammability of Interior Materials*. It should be noted that any additional weight created by your modifications or a change in the distribution of weight could also affect the vehicle's compliance with other safety standards whose test procedures require a barrier crash test.; We also would point out that if you modify a Ford 'Econoline' in al probability you would change the vehicle classification from a truck to a multipurpose passenger vehicle. This should be noted on the certification label that you attach to the vehicle.; I have enclosed an information sheet that explains where you may obtai copies of these regulations.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam5245OpenMr. Thomas Dougherty C.A.P.S. Inc. 1712 Rudder Industrial Park Drive Fenton, MO 63026; Mr. Thomas Dougherty C.A.P.S. Inc. 1712 Rudder Industrial Park Drive Fenton MO 63026; "Dear Mr. Dougherty: This responds to your letter asking about how thi agency's regulations might apply to your product, the 'E.A.R.S.' system. You state that your product contains an LED light and an 82 decibel tone and serves to alert hearing impaired drivers of approaching emergency vehicles. You further state that the part of the system that alerts drivers plugs into the cigarette lighter, while a microphone is placed outside the vehicle. (You did not explain how or where the microphone is placed or whether a hole is drilled through the windshield.) I am pleased to have this opportunity to explain our regulations. I am also enclosing a copy of a fact sheet titled 'Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment.' By way of background information, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards (FMVSS's) for new motor vehicles and new items of motor vehicle equipment. Section 102(4) of the National Traffic and Motor Vehicle Safety Act (the 'Safety Act') defines, in relevant part, the term 'motor vehicle equipment' as: any system, part, or component of a motor vehicle as originally manufactured or any similar part or component manufactured or sold for replacement or improvement of such system, part, or component or as any accessory, or addition to the motor vehicle ... (emphasis added). In determining whether an item of equipment is considered an accessory, NHTSA applies two criteria. The first criterion is whether a substantial portion of the expected use of the item is related to the operation or maintenance of motor vehicles. We determine a product's expected use by considering product advertising, product labeling, and the type of store that retails the product, as well as available information about the actual use of the product. The second criterion is whether the product is intended to be used principally by ordinary users of motor vehicles. If the product satisfies both criteria, then the product is considered to be an 'accessory' and thus is subject to the provisions of the Safety Act. Applying these criteria to the E.A.R.S. system, it appears that this product would be an accessory and thus an item of motor vehicle equipment under the Safety Act. Based on our understanding of the product, it appears that the entire portion of the expected use of the E.A.R.S system relates to motor vehicle operation. That is, the system is intended to alert the vehicle driver about an oncoming emergency vehicle. Also, it appears that the product would typically be used by ordinary users of motor vehicles, in particular, hearing impaired drivers. While it appears that the E.A.R.S. system is an item of motor vehicle equipment, NHTSA has not issued any standards for such a device. Nevertheless, there are other Federal laws that indirectly affect the manufacture and sale of your product. You as the product's manufacturer are subject to the requirements in sections 151-159 of the Safety Act concerning the recall and remedy of products with defects related to motor vehicle safety. In the event that the manufacturer or NHTSA determines that the product contains a safety related defect, the manufacturer would be responsible for notifying purchasers of the defective equipment and remedying the problem free of charge. A commercial business that installs the E.A.R.S. system would also be subject to provisions of the Safety Act that affect modifications of new or used vehicles. Section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)) provides that: No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle ... in compliance with an applicable Federal motor vehicle safety standard. This means that a manufacturer, distributor, dealer, or motor vehicle repair business must not install your device if the system renders inoperative the vehicle's compliance with the FMVSS's. For instance, compliance with Standard No. 205 might be degraded if it were necessary to drill a hole through the windshield. Any violation of this 'render inoperative' prohibition would subject the violator to a potential civil penalty of up to $1,000 for each violation. Please note also that the render inoperative prohibition does not apply to modifications that vehicle owners make to their own vehicles. Thus, Federal law would not apply in situations where individual vehicle owners install the E.A.R.S. system in their own vehicles, even if the installation were to result in the vehicle no longer complying with the safety standards. However, NHTSA encourages vehicle owners not to degrade any safety device or system installed in their vehicles. In addition, individual States have the authority to regulate modifications that individual vehicle owners may make to their vehicles, so you might wish to consult State regulations to see whether your device would be permitted. 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, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam5408OpenMrs. Carmen Colet Vice President John Russo Industrial, Inc. 575 West San Carlos Street San Jose, CA 95126; Mrs. Carmen Colet Vice President John Russo Industrial Inc. 575 West San Carlos Street San Jose CA 95126; "Dear Mrs. Colet: This responds to your request for an interpretatio whether Standard No. 115, Vehicle identification number - basic requirements or any other Federal Motor Vehicle Safety Standard (FMVSS) applies to your 'aircraft rescue and fire- fighting vehicle.' As explained below, the answer is no. Your letter states that your company is constructing the vehicle 'to satisfy proposed U.S.A.F. and D.O.D.' specifications. The vehicle is made to operate on airfields. You described the unusual configuration of the vehicle as having a 'cockpit' that is 'similar to 117A Stealth Fighter,' having bumpers that are 5 feet high, and having a 'power water turret on top.' You further stated that vehicle uses tires 54 inches high and over two feet wide, that are made to be run on only for 20 minutes, at a speed of up to 65 miles per hour. Enclosed with your letter is a picture of the vehicle, which you asked be kept confidential. Although your request for confidentiality does not comply with NHTSA's regulations at 49 CFR part 512 Confidential Business Information, in order to save time, I will not publicly disclose the picture. The FMVSSs apply only to 'motor vehicles,' within the meaning of 49 U.S.C. 30102(a)(6). 'Motor vehicle' is defined at section 30102(a)(6) as: a vehicle driven or drawn by mechanical power and manufactured primarily for use on public streets, roads, and highways, but does not include a vehicle operated only on a rail line. We have interpreted this language to mean that vehicles designed and sold solely for off-road use are not considered motor vehicles, even though they may be operationally capable of highway travel. In an interpretation letter of December 28, 1979, to Walter Motor Truck Company, NHTSA determined that the Walter airport crash-fire-rescue vehicle does not qualify as a motor vehicle subject to the FMVSS. Your description of your aircraft rescue vehicle indicates that the vehicle is to be used only within an airfield. In particular, the size and 20 minute running time of the tires, appears to make the vehicle impracticable for highway use. Based on the information you have provided, and our understanding that your vehicles are neither used on public roads nor suitable for such use, we conclude that the 'aircraft rescue and fire-fighting vehicle' is not a 'motor vehicle' within the meaning of the National Traffic and Motor Vehicle Safety Act. Thus, your vehicle is not subject to Standard No. 115. Since you are not a manufacturer of a 'motor vehicle,' you do not have to furnish NHTSA with information pursuant to 49 CFR part 566 Manufacturer Identification. Enclosed with this letter is your picture of the aircraft rescue and fire- fighting vehicle. If you have any questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam0199OpenMr. Bernard Belier, U. S. Resident Engineer, U. S. Technical Research Corporation, 801 Second Avenue, New York, NY 10017; Mr. Bernard Belier U. S. Resident Engineer U. S. Technical Research Corporation 801 Second Avenue New York NY 10017; Dear Mr. Belier: This is in reply to your letter, dated November 11, 1969, in which yo seek an interpretation as to how Federal Motor Vehicle Safety Standards (FMVSSs) 103 and 104 are applicable to cars equipped with right-hand drive or a central steering wheel.; For motor vehicles equipped with right-hand drive, the windshield area to be defrosted and wiped by FMVSSs 103 and 104 respectively, are mirror images of those areas required for vehicles equipped with left-hand drive.; More information is required before a reply can be given on vehicle equipped with a central steering wheel. Defrosting and wiping areas requirements would naturally vary depending on the number and location of the front seat passenger seating positions in the vehicle equipped with a central steering wheel.; We trust that we have been of assistance to you. Sincerely, Robert Brenner,Acting Director |
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ID: aiam0197OpenMr. Bernard Belier, U. S. Resident Engineer, U. S. Technical Research Corporation, 801 Second Avenue, New York, NY 10017; Mr. Bernard Belier U. S. Resident Engineer U. S. Technical Research Corporation 801 Second Avenue New York NY 10017; Dear Mr. Belier:#This is in reply to your letter, dated November 11 1969, in which you seek an interpretation as to how Federal Motor Vehicle Safety Standards (FMVSSs) 103 and 104 are applicable to cars equipped with right-hand drive or a central steering wheel.#For motor vehicles equipped with right-hand drive, the windshield areas to be defrosted and wiped by FMVSSs 103 and 104 respectively, are mirror images of those areas required for vehicles equipped with left-hand drive.#More information is required before a reply can be given on vehicles equipped with a central steering wheel. Defrosting and wiping areas requirements would naturally vary depending on the number and location of the front seat passenger seating positions in the vehicle equipped with a central steering wheel.#We trust that we have been of assistance to you.#Sincerely, Robert Brenner, Acting Director; |
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.