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: 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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ID: aiam3837OpenMs. Doris A. Lindley, Purchasing Agent, Hayes Equipment Corporation, P.O. Box 526, 150 New Britain Avenue, Unionville, CT 06085; Ms. Doris A. Lindley Purchasing Agent Hayes Equipment Corporation P.O. Box 526 150 New Britain Avenue Unionville CT 06085; Dear Ms. Lindley: This responds to your letter to Mr. Kratzke of my staff, requestin information on the tire registration requirements applicable to your company as a manufacturer of new trailers. Per your request, I have enclosed a copy of the Motor Vehicle Safety and Cost Savings Authorization Act of 1982. You also asked for confirmation that your company, as the manufacturer of trailers, has sole responsibility for keeping records of the tire identification numbers of the tires shipped as original equipment on trailers sold under your company's name. Your understanding is correct.; The responsibility of the various parties for recording and keepin records of the tire identification numbers of new tires are set forth in 49 CFR Part 574, *Tire Identification and Recordkeeping*. Section 574.10 reads as follows:; >>>Each motor vehicle manufacturer, or his designee, shall maintain record of the new tires on or in each vehicle shipped by him or a motor vehicle distributor or dealer, and shall maintain a record of the name and address of the first purchaser for purposes other than resale of each vehicle equipped with such tires. These records shall be maintained for a period of not less than 3 years from the date of sale of the vehicle to the first purchaser for purposes other than resale.<<<; As you can see from this language, it is the vehicle manufacturer tha has the sole responsibility for keeping records of the tire identification numbers of the tires shipped as original equipment on or in the vehicle and records of the first purchasers of those vehicles for purposes other than resale. This responsibility remains even if the tires on the vehicle are changed by a vehicle dealer or distributor, unless that dealer or distributor voluntarily notifies the vehicle manufacturer of the tire change. As long as the vehicle is sold with the tires that were shipped with it as original equipment, dealers and distributors of the vehicle have no responsibilities for either registering the tires or keeping any records. Should those dealers and distributors substitute tires on the vehicle other than those shipped as original equipment, they would have some responsibility for registering the tires with the tire manufacturer, per section 574.9, but it would be the tire manufacturer that would be responsible for keeping the records, not the dealers and distributors.; Should you have any further questions relating to tire registratio requirements, please contact Mr. Kratzke at this address or by telephone at (202) 426-2992.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0718OpenMr. John E. Wade, Purchasing Manager, Rok-A-Chair Manufacturing Co., Inc., P. O. Box 254, North Central Street, Coffeyville, KS, 67337; Mr. John E. Wade Purchasing Manager Rok-A-Chair Manufacturing Co. Inc. P. O. Box 254 North Central Street Coffeyville KS 67337; Dear Mr. Wade: In reply to your letter of May 9, 1972, I have enclosed a copy of Moto Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' which specifies flammability requirements for materials used in motor vehicles.; The standard applies to passenger cars, multipurpose passenge vehicles, trucks, and buses. Among the recreational vehicles you list, motor homes and chassis-mount campers mounted on new chassis would be included. Mobile homes and travel trailers are not subject to the standard. Slide-in campers and chassis-mount campers that are not mounted on new chassis are not presently subject to the standard, but NHTSA is considering amendments that would bring these camper types within the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2725OpenMr. James O. Peterson, Administrator, Division of Motor Vehicles, Department of Transportation, 4802 Sheboygan Avenue, Madison, WI 53707; Mr. James O. Peterson Administrator Division of Motor Vehicles Department of Transportation 4802 Sheboygan Avenue Madison WI 53707; Dear Mr. Peterson: This responds to your September 20, 1977, letter asserting that th Wisconsin requirement for minimum seat spacing does not conflict with the Federal requirement for maximum seat spacing found in Standard No. 222, *School Bus Passenger Seating and Crash Protection*.; Section 103(d) of the National Traffic and Motor Vehicle Safety Act o 1966 (the Act) (15 U.S.C. 1381 *et seq*.) specifies that no State shall have in effect a safety standard concerning an aspect of performance regulated by a Federal safety standard, unless the State standard is identical. The Act provides a limited exception to the above where a State or local municipality has a requirement which applies only to vehicles purchased for their own use and which imposes a higher standard of performance. Both Standard No. 222, which regulates maximum seat spacing, and the Wisconsin standard, which regulates minimum seat spacing, regulate the same aspect of performance. This position is supported by our statements in Notice 5 of Standard No. 222 (41 FR 4016) which expressed the opinion that seat spacing is the regulated aspect of performance (copy enclosed). Since your State standard is not identical to the Federal standard, it is the opinion of the NHTSA that it is preempted.; You should note that although you are not permitted to impose thi State standard on all vehicles used in your State, the Federal government does not preclude you from purchasing any buses for your own use from among the several designs now in production. You could, therefore, purchase only those vehicles that afford you the minimum knee space you desire. You should note further that purchase for your own use has been interpreted to mean purchased by a contractor under contract to provide transportation for school children.; Sincerely, Joan Claybrook |
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ID: aiam0348OpenMr. Jack Lewis, Legislative Assistant, Senator Spong's Office, United States Senate, Washington, DC 20510; Mr. Jack Lewis Legislative Assistant Senator Spong's Office United States Senate Washington DC 20510; Dear Mr. Lewis: This is in reply to your telephone conversation of May 19, 1971 with member of this office concerning Part 574 - Tire Identification and Record Keeping.; In your conversation you asked what the position of the Nationa Highway Traffic Safety Administration would be if a retreader could establish he was unable to obtain, by May 22, 1971, the effective date of the regulation, the necessary tin plate for placing the required tire identification number on his retreaded tires.; Of course, each case would be considered individually, but if retreader could demonstrate that good faith attempts had been made to obtain the tin plate by May 22, 1971, and due to circumstances beyond his control he was unable to mark tires manufactured after May 22, 1971 with the required identification number, the National Highway Traffic Safety Administration would not take enforcement action against the retreader.; Sincerely, Lawrence R. Schneider, Acting 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.