NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
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ID: aiam0061OpenMaurice Wexler, Esq., Heiskell, Donelson, Adams, Williams & Wall, Suite 2020 First National Bank Building, Memphis, TN 38103; Maurice Wexler Esq. Heiskell Donelson Adams Williams & Wall Suite 2020 First National Bank Building Memphis TN 38103; Dear Mr. Wexler: Mr. Bridwell has asked that I reply to your letter of April 9, 1968. Enclosed for your information is a copy of the chassis-cab ruling an regulation issued December 29, 1967. Under the terms of the ruling and regulation and the National Traffic and Motor Vehicle Safety Act of 1966, when a truck body manufacturer assembles the truck body to a chassis-cab he is responsible for certification only if the completed vehicle is delivered to a dealer or distributor. The body manufacturer assembling the body to the chassis-cab would, however, be responsible for the vehicle's compliance with the lighting standard if not previously met by the chassis-cab manufacturer. Moreover if the addition of the body affects the chassis-cabs previous compliance with standards the body manufacturer would be responsible for compliance.; With regard to bodies mounted on chassis-cabs manufactured prior t January 1, 1968 compliance and certification is not required. However, the body, if manufactured on or after January 1, 1968, would have to contain glazing that complies with Standard No. 205 because the body is manufactured for use on motor vehicles and as such must meet any applicable equipment standards.; Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel |
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ID: aiam5633OpenMr. James J. Gregorio 6704 Forsythia St. Springfield, VA 22150; Mr. James J. Gregorio 6704 Forsythia St. Springfield VA 22150; "Dear Mr. Gregorio: This responds to your letter of September 23, 1995 requesting 'authorization to modify the car seat in my 1992 Plymouth Acclaim.' Your letter states: Presently, my car is equipped with hand controls which alleviates a condition of chronic tendinitis in my right ankle. Unfortunately, there is practically no room between the hand controls and my knees. My knees constantly bang up against the hand controls. The resulting consequence is that I now have tendinitis in both knees. Modifying the car seat will allow me to push the car seat back far enough to give space to my injured knees. You enclosed a letter from your physician stating that recovery could take several years. In summary, our answer is that you may have your vehicle modified. NHTSA will not institute enforcement proceedings against a repair business that modifies the seat on your vehicle to accommodate your condition. A more detailed answer to your letter is provided below. I would like to begin by noting that repair businesses are permitted to modify vehicles without obtaining permission from NHTSA to do so, but are subject to certain regulatory limits on the type of modifications they may make. In certain limited situations, we have exercised our discretion in enforcing our requirements to provide some allowances to a repair business which cannot conform to our requirements when making modifications to accommodate the special needs of persons with disabilities. Since your situation is among those given special consideration by NHTSA, this letter should provide you with the relief you seek. Our agency is authorized to issue Federal Motor Vehicle Safety Standards (FMVSS) that set performance requirements for new motor vehicles and items of motor vehicle equipment. Manufacturers are required to certify that their products conform to our safety standards before they can be offered for sale. Manufacturers, distributors, dealers, and repair businesses are prohibited from 'knowingly making inoperative' any device or element of design installed on or in a motor vehicle in compliance with an applicable FMVSS. In general, the 'make inoperative' prohibition would require repair businesses which modify motor vehicles to ensure that they do not remove, disconnect, or degrade the performance of safety equipment installed in compliance with an applicable FMVSS. Violations of this prohibition are punishable by civil fines up to $1,000 per violation. Moving a seat, and presumably moving the seat belts for the seat, could affect compliance with four safety standards: Standard No. 207, Seating Systems, Standard No. 208, Occupant Crash Protection, Standard No. 209, Seat Belt Assemblies, and Standard No. 210, Seat Belt Assembly Anchorages. Your letter does not provide any information regarding why the modification to your seat cannot be done in a way that would not violate the make inoperative prohibition. However, in situations such as yours where a vehicle must be modified to accommodate the needs of a particular disability, we have been willing to consider any violations of the 'make inoperative' prohibition a purely technical one justified by public need. As I have already noted above, NHTSA will not institute enforcement proceedings against a repair business that modifies the seat on your vehicle to accommodate your condition. We caution, however, that only necessary modifications should be made to the seat, and the person making the modifications should consider the possible safety consequences of the modifications. For example, in moving a seat, it is critical that the modifier ensure that the seat is solidly anchored in its new location. You should also be aware that an occupant of a seat which has been moved rearward may have less protection in a crash if the seat is too far rearward relative to the anchorages of the safety belts for that seat. Finally, if you sell your vehicle, we encourage you to advise the purchaser of the modifications. I hope this information has been helpful. If you have any other questions or need some additional information in this area, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, Samuel J. Dubbin Chief Counsel"; |
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ID: aiam4921OpenCarl Miller, O.E. Sales Manager DICO Tire, Inc. 520 J.D. Yarnell Industrial Parkway Clinton, TN 37716; Carl Miller O.E. Sales Manager DICO Tire Inc. 520 J.D. Yarnell Industrial Parkway Clinton TN 37716; "Dear Mr. Miller: This responds to your letter asking about th application of 49 CFR Part 574, Tire Information and Recordkeeping, to new tires sold in the replacement market. You indicated that, as a manufacturer of boat trailer tires, you believed that Part 574 required you to provide recall information cards for every new tire, whether that tire was to be installed as original equipment or sold in the replacement market. You added, however, that you heard that the National Highway Traffic Safety Administration (NHTSA) had recently restricted the application of this requirement to tires sold as original equipment. Accordingly, you requested the agency to confirm that information. NHTSA has made no amendments to Part 574 that would restrict the requirement that tire manufacturers provide recall information cards only for those tires sold as original equipment. Hence, tire manufacturers remain subject to the requirement that they provide such cards to every distributor and dealer that sells the manufacturer's new tires, regardless of whether those new tires are sold as original equipment on a vehicle or as an individual replacement item. Part 574 sets forth tire information and recordkeeping requirements to facilitate notification of purchasers in the event that a manufacturer must recall a tire to remedy a safety-related defect, or a noncompliance with an applicable Federal Motor Vehicle Safety Standard. Among Part 574's requirements, 574.7 specifies requirements for tire registration forms. I believe these forms are what your letter refers to as 'recall information cards.' 574.7 requires each new tire manufacturer and each new tire brand name owner (or its designee) to provide tire registration forms to every distributor and dealer of its tires which offers 'new tires for sale or lease to tire purchasers.' 49 CFR 574.7(a)(1) Part 574 defines 'tire purchaser' as 'a person who buys or leases a new tire, or who buys or leases for 60 days or more a motor vehicle containing a new tire for purposes other than resale.' 49 CFR 574.3(5) Thus, 574.7(a)(1) explicitly requires that tire registration forms be provided to every distributor or dealer that offers a manufacturer's new tires for sale to the public. 574.7 makes no distinction between tires to be sold as original equipment and tires sold as replacement products. For your information, I have enclosed a copy of 49 CFR Part 574 and have highlighted the provisions that relate to your question. I hope this information is helpful. Please contact Elizabeth Barbour of my staff at this address or by telephone at (202) 366-2992 if you have further questions. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam0431OpenMr. Kenneth W. Brown, Cabot Corporation, 125 High Street, Boston, Massachusetts 02110; Mr. Kenneth W. Brown Cabot Corporation 125 High Street Boston Massachusetts 02110; Dear Mr. Brown: This is in reply to your letters of March 10 and July 1, 1971 requesting an exemption from Motor Vehicle Safety Standard No. 117 for experimental tires that you manufacture by buffing off the tread of new tires and then recapping the tires with different compounds. You state that you use these tires for testing carbon blacks by testing the tires on the public highways and on private test tracks.; We do not consider tires manufactured by the method you describe to b retreaded tires within the scope of Standard No. 117 because they are not manufactured from used tires. However, we do consider them to be new pneumatic tires, and subject to the requirements of Motor Vehicle Safety Standard No. 109. We regret that an earlier letter to you of April 7, 1971, may have been misleading in that regard.; Section 108(a)(1) of the National Traffic and Motor Vehicle Safety Ac (15 U.S.C. S1397(a)(1)) provides that no person shall --; >>>'manufacture for sale, sell, offer for sale, or introduce or delive for introduction interstate commerce... any motor vehicle or item of motor vehicle equipment manufactured on or after the date any applicable Federal motor vehicle safety standard take effect... unless it is in conformity with such standard.'<<<; We consider the testing of these tires on the public roads to be a introduction of them in interstate commerce, and prohibited by section 108(a)(1) unless the tires conform to standard No. 109. The tires need not be manufactured for sale to the general public in order for violations of section 108(a)(1) to occur. However, if the testing of these tires is confined to the laboratory or to private roads, the prohibition of the section 108(a)(1) will not apply to them.; A copy of the Act and Motor vehicle Safety Standard No. 109 is enclose for your information.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4472OpenMr. Donald Smith Chief Inventor New Innovative Systems 1047 E. Vernon Road Philadelphia, PA 19146; Mr. Donald Smith Chief Inventor New Innovative Systems 1047 E. Vernon Road Philadelphia PA 19146; Dear Mr. Smith: This is in reply to your recent undated lette regarding the 'Highway Automatic Communications Indicator (HACI)', as supplemented by a telephone conversation between you and Stephen Wood of my staff on December 20, l988. You have asked for approval of your device. The HACI 'will display, via a transparent display screen mounted in the rear window, pre-programmed distress messages, activated only when with the automobile is at a complete standstill.' The diagram of the display alert indicates that the message would appear in the middle of the rear window, rather than at the bottom of the window where the lamp would be. When not activated, the device would be transparent. It would be activated by a special switch, not by the brake pedal. It is our understanding that the HACI would be activated only when the vehicle is stationary, and is not wired into the brake light or hazard light system. The National Highway Traffic Safety Administration has no authority to approve or disapprove individual inventions or devices. We can, however, advise you as to the relationship of the HACI to the Federal motor vehicle safety standards and the National Traffic and Motor Vehicle Safety Act under the authority of which the standards are issued. These standards must be met at the time a vehicle is sold to its first purchaser, and persons other than the purchaser may not modify a vehicle after its sale in a manner that, in essence, renders it noncompliant with any standard. There are three standards potentially affected by the HACI. The first is the lighting standard, Standard No. 108. Since the HACI's display screen is mounted in the rear window, a problem could arise if the center high mounted stop lamp required by Standard No. 108 is also mounted in that area. The HACI is permissible as original vehicle equipment as long as it does not impair the effectiveness of the high mounted lamp, or any other lamp required by Standard No. 108. While this determination is the responsibility of the vehicle manufacturer (or dealer, if the HACI is installed after vehicle manufacture but before sale to its first purchaser) in the first instance, it appears to us that the effectiveness of the high mounted lamp would not be impaired. We base this conclusion on our understanding that the message would appear in the middle of the rear window, instead of at the bottom of the window where the lamp would be and that it would apparently be activated only when the vehicle was stationary, such as parked on the side of the road. The second standard potentially affected is Standard No. lll, relating to rearview mirrors. This standard specifies a field of view to be met by the inside rearview mirror, if the mirror does not provide this field of view, an outside mirror on the front seat passenger side must be provided. Since your device is reportedly transparent when not activated, and would be activated only when the vehicle is stationary, it may well be that there is no necessity for the addition of an outside mirror. However, we do not have sufficient information to determine whether the HACI would impede the field of view under all conditions. The third standard potentially affected is Standard No. 205, relating to glazing. This requires, in part, that all glazing in passenger cars have at least 70 percent light transmittance. To the extent that the display screen reduces light transmittance, it could create a noncompliance with this standard. However, because you have indicated that your display screen is transparent, it does not appear likely that any reduction in light transmittance would fall below the specified minimum. With this guidance and your knowledge of the HACI, you should be able to judge whether installation of the HACI either before or after the initial sale of a passenger car might be regarded as creating a noncompliance with a Federal motor vehicle safety standard, or otherwise be in violation of the Act. An official judgment regarding noncompliance or violation is made by the agency only in the context of an enforcement proceeding. In addition, you should be aware that the HACI remains subject to the laws of the individual States. We cannot advise you of its legality under these laws. To obtain an opinion on this matter, you may wish to consult the American Association of Motor Vehicle Administrators, 4600 Wilson Blvd., Arlington, Va. 22203. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam4188OpenMr. Charles J. Newman, Vice-President, Engineering, The Grote Manufacturing Company, 2600 Lanier Drive, Madison IN 47250; Mr. Charles J. Newman Vice-President Engineering The Grote Manufacturing Company 2600 Lanier Drive Madison IN 47250; Dear Mr. Newman: This is in reply to your letter of December 10, 1985, asking for a interpretation regarding two proposed locations for clearance lamps. As you know, our response has been delayed because the original letter lacked one of the two drawings necessary for us to reply to your questions.; You have paraphrased S4.3.1.1.1 of Standard No. 108 as stating 'in par that clearance lamps need not be mounted on the front or rear and at such a location need not be visible at 45 degrees inboard.' That is not exactly what that section permits. It states that 'Clearance lamps may be mounted at a location other than on the front and rear if necessary to indicate the overall width of a vehicle, or for protection from damage during normal operation of the vehicle, and at such a location they need not be visible at 45 degrees inboard.' Your first request for an interpretation concerns a 'fixed body with additional equipment mounted on the box,' and depicts clearance lamps that are mounted on the front of a structure behind the cab, and yet are not visible at 45 degrees inboard. You have asked whether this meets the intent of S4.3.1.1.1. The plan view diagram in your letter indicates that the clearance lamps if mounted on the front (i.e., the cab) would not be located to indicate the overall width of the vehicle. But when mounted on the structure behind the cab, they appear located so as to indicate the overall width of the vehicle. You have not mentioned mounting height, but we assume that they are 'as close to the top as practicable' in accordance with the requirements of Table II of Standard No. 108. Therefore the exception permitted by S4.3.1.1.1 would apply.; Your second request covers a 'side mounted clearance lamp, and state that 'Because of box construction and box size, a side mounted clearance lamp is a better location.' In this location, the inboard visibility requirements would not be met. You asked whether this would meet the intent of S4.3.1.1.1.; The intent of S4.3.1.1.1 is that the alternate location indicate th overall width of the vehicle. If we judge compliance by the plan view of the diagram, then the location on the second diagram is acceptable. But in this location the inboard angle of visibility would be even less than in the first diagram, and the overall width of the vehicle would be less apparent to an incoming (sic) driver. Given the fact that you have presented us with alternative means by which you may meet S4.3.1.1.1 we cannot conclude that the location shown in the second diagram complies with Standard No. 108.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1670OpenMr. Charles W. Chandler, Manager of Engineering, Vulcan Trailer Manufacturing Co., P.O. Box 5099, Pratt City Station, Birmingham, AL 35214; Mr. Charles W. Chandler Manager of Engineering Vulcan Trailer Manufacturing Co. P.O. Box 5099 Pratt City Station Birmingham AL 35214; Dear Mr. Chandler: This responds to Vulkan's (sic) November 7, 1974, question whether it Model FTD-6540 'drop deck platform' trailer qualifies as a 'Heavy hauler trailer' which is not subject to the requirements of Standard No. 121, *Air brake systems*, until September 1, 1976. 'Heavy hauler trailer is defined in S4. of the standard as follows:; >>>'Heavy hauler trailer' means a trailer with one or more of th following characteristics:; (1) Its brake lines are designed to adapt to separation or extension o the vehicle frame, or; (2) Its body consists only of a platform whose primary cargo-carryin surface is not more than 40 inches above the ground in an unloaded condition, except that it may include sides that are designed to be easily removable and a permanent 'front-end structure' as that term is used in S 393.106 of this title.<<<; From the description you enclosed, it appears that the FTD-6540 mode has a primary cargo-carrying surface that is not more than 40 inches above the ground in the unloaded condition, and that it would therefore not be required to meet the standard until September 1, 1976.; It should be emphasized that the 40-inch height is an absolute limi for regulatory purposes, and that reliance on a design height of 40 inches will probably result in the production of some non- complying vehicles due to variations in manufacture. A maximum civil penalty of $1,000 is authorized for each such non- compliance (15 U.S.C. S 1398(a)).; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0962OpenMr. Satoshi Nishibori, Nissan Motor Company, 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Satoshi Nishibori Nissan Motor Company 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Nishibori: This is in reply to your letter of December 14, 1972, concerning th acceptability, under S7.4 of Standard 208, of a time delay device in a belt interlock system.; As described in your letter, the delay device would permit an occupan who has operated the belt in the correct sequence to lift off the seat while buckled for a brief period *before* attempting to start the vehicle. Under S7.4 as presently constituted, this action by the occupant would result in the belt's being buckled before the seat is occupied. The occupant would therefore have to unbuckle the belt and rebuckle before starting the car. A time delay device, in short, would not be allowable.; We make no comment that this situation is desirable or undesirable, bu it is, however, required by the language of S7.4.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4022OpenMr. David Walsh, 16892 Centralia, Redford, MI 48240; Mr. David Walsh 16892 Centralia Redford MI 48240; Dear Mr. Walsh: Thank you for your letter of September 15, 1985, inquiring about th Federal safety standards that apply to a product you have developed. You described the product as a mini-venetian blind that is held on a side window of a vehicle by four suction cups. The purpose of the blind is to shield vehicle occupants from the sun. The following discussion explains the applicability of our safety standards to your product.; Pursuant to the National Traffic and Motor Vehicle Safety Act, we hav issued Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials*, which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70% in areas requisite for driving visibility, which includes all windows in passenger cars).; No manufacturer or dealer is permitted to install solar films and othe sun screen devices, such as the one described in your letter, in *new* vehicles without certifying that the vehicle continues to be in compliance with the light transmittance and other requirements of the standard.; After a vehicle is first sold to a consumer, modifications to a vehicl are affected by section 108(a)(2)(A) of the Vehicle Safety Act. That section prohibits commercial businesses from tampering with safety equipment installed on a vehicle in compliance with our standards. Thus, no dealer, manufacturer, repair business or distributor can install a sun screen device for the owner of the vehicle, if the device would cause the window not to meet the requirements of Standard No. 205. Violation of the 'render inoperative' provision can result in Federal civil penalties of up to $1,000 for each violation.; Section 108(a)(2)(A) does not affect vehicle owners, who may themselve alter their vehicles as they please, so long as they adhere to all State requirements. Under Federal law, the owner may install sun screening devices regardless of whether the installation adversely affects the light transmittance. Individual States govern the operational use of vehicles by their owners and therefore it is within the authority of the States to preclude owners from applying sun screens on their vehicles. You asked about State laws affecting your product. I suggest you contact the American Association of Motor Vehicle Administrators, which may be able to tell you about State laws or refer you to the appropriate officials in the States in which you wish to sell your product. The address for AAMVA is Suite 910, 1201 Connecticut Avenue, N.W., Washington, DC 20036.; If you need further information, please lt me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1220OpenMr. H. Hirai, Technical Representative, Toyo Kogyo U.S.A. Representative Office, 23777 Greenfield Rd. S426, Southfield, MI, 48075; Mr. H. Hirai Technical Representative Toyo Kogyo U.S.A. Representative Office 23777 Greenfield Rd. S426 Southfield MI 48075; Dear Mr. Hirai: This is in reply to your letter of August 20, 1973, regarding th applicability of Standard No. 302, 'Flammability of Interior Materials,' to a paper instruction sheet your Company may wish to place on the driver's side sun visor or on some other interior component to inform occupants about the seat belt interlock system.; The applicability of Standard No. 302 depends on whether th instruction sheet is attached in such a way as to form a permanent part of the sun visor or a permanent part of some other interior component covered by the standard. If the instruction sheet is easily removable and obviously not part of any component which must meet the requirements of the standard, we would not consider it to be part of any such component and, therefore, it would not be subject to the standard.; 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.