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: aiam1683OpenMr. Jeffrey B. Lugash, Suite 2200, 1801 Century Park East, Los Angeles, California 90067; Mr. Jeffrey B. Lugash Suite 2200 1801 Century Park East Los Angeles California 90067; Dear Mr. Lugash: This responds to your October 30, 1974, questions whether th Department of Transportation or any 'private establishment' requires manufacturers to file specifications for automobile, motorcycle, and airplane tires, whether Standard No. 119, *New pneumatic tires for vehicles other than passenger cars*, lists these specifications, and what the number '222474 7MRR' means on the bead of a motorcycle tire.; The Department of Transportation's National Highway Traffic Safet Administration has issued Standard No. 119 (effective March 1, 1975), which establishes minimum performance and labeling requirements with which the manufacturer must comply. A copy of the standard is enclosed. Certain tire specifications must appear on the sidewall, and certain rim-matching specifications must be published by the manufacturer or appear in a publication of at least one private tire organization.; It is the general practice of the tire industry to list specification of tires in a private publication, such as the 'Year Book' of the Tire and Rim Association in the United States. Their address is: The tire and Rim Association, Inc., 3200 West Market Street, Akron, Ohio 44313.; The NHTSA Tire and Wheel Division has determined that the number whic you cite is of significance only to the manufacturer of the tire.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3344OpenMr. R. H. Madison, Engineering Consultant, 12814 Ashbury Drive, Tantallon, MD 20022; Mr. R. H. Madison Engineering Consultant 12814 Ashbury Drive Tantallon MD 20022; Dear Mr. Madison: This responds to your June 25, 1980, letter asking whether a propose air brake system that you submitted would comply with the requirements of Standard No. 121, *Air Brake Systems*.; The National Highway Traffic Safety Administration (NHTSA) does no issue advance approval of systems constructed in compliance with safety standards. It is the responsibility of manufacturers to assure that their vehicles or equipment comply with the requirements of the safety standards. It is frequently impossible for the agency to tell from diagrams and descriptions of devices whether they will comply with the standards. Compliance is based upon testing and observation of the entire vehicle or piece of equipment as it is installed on the vehicle. Without the benefits of such tests, NHTSA cannot state whether your system would comply with Standard No. 121.; Our engineering staff has reviewed your letter and offers the followin information. First, the standard contains no requirements for tractor protection valve control pressures. However, control pressures are usually set so that the trailer brakes apply before the tractor brakes.; Second, you asked whether it is appropriate to require the release o parking brakes by pushing in both the tractor protection control valve and the park valve. The standard states that the parking brake control shall control the parking brakes of the vehicle and any vehicle it is designed to tow. The standard is silent regarding the release of those brakes.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4481OpenMr. Max J. Mizejewski Foreign Marketing Specialists, Inc. 14451 Chambers Rd., Suite 155 Tustin, CA 92680; Mr. Max J. Mizejewski Foreign Marketing Specialists Inc. 14451 Chambers Rd. Suite 155 Tustin CA 92680; "Dear Mr. Mizejewski: This is in response to your letter in which yo asked whether a product your company plans to import would be subject to any Federal motor vehicle safety standard (FMVSS). According to your letter, this product, which you refer to as a 'Roadreader,' attaches to the front of a motor vehicle and has two sensors which give a visual and audible alarm when the vehicle drifts off a road. You indicated that this product would be connected to the wiring related to the turn signals. You noted that this device does not affect vehicle functions such as acceleration, braking, lighting, or visibility. You further stated that if required, you would provide the device to NHTSA or another government agency for inspection. Section 103 of the National Traffic and Motor Vehicle Safety Act ('Safety Act') directs the National Highway Traffic Safety Administration (NHTSA) to establish safety standards for motor vehicles and motor vehicle equipment. Title 49 CFR Part 571 contains the safety standards promulgated by the agency. Although you stated that this device does not affect the electrical wiring related to the turn lights, I suggest you closely review Standard No. 108, Lamps, Reflective Devices, and Associated Equipment (Copy enclosed). This safety standard applies to both motor vehicle equipment installed in new motor vehicles and replacement equipment sold in the aftermarket. While I cannot conclusively say that this standard is or is not applicable to your product based on the limited facts in your letter, this standard may apply to your product because the wiring for your device is connected to components (i.e., turn lights) subject to the standard. For instance, S4.5.11 requires that components including the turn signal lamps must be wired to flash. More generally, S4.1.3 forbids the installation of an additional piece of motor vehicle equipment that impairs the lighting equipment required by Standard No. 108. Therefore, a device such as yours is permissible as original vehicle equipment provided that it does not impair the effectiveness of the lighting equipment required by the standard. As for the sale of your product in the aftermarket for vehicles in use, Section 108 of the Safety Act prohibits a manufacturer, distributor, dealer, or motor vehicle repair business from knowingly rendering inoperative any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with a FMVSS. Since an importer is defined by the Safety Act as a manufacturer, you should assure that installation of your device does not render inoperative, in whole or in part, the turn signal lamp or any other item of motor vehicle equipment subject to Standard No. 108. As for your second question concerning inspection and approval of your product, you should be aware that NHTSA does not provide approvals of motor vehicles and motor vehicle equipment. Under Section 114 of the Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with all applicable safety standards. Further, as you noted, you would be responsible for recalling any safety-related defects which you or this agency finds in your product. You also should be aware that laws from particular States may apply to your device. Therefore, you may wish to contact the State and local transportation authorities in the areas where you intend to market your product. The American Association of Motor Vehicle Administrators (4600 Wilson Boulevard, Arlington, Va. 22203) may also be able to provide information about State laws concerning devices similar to your product. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam1379OpenMr. Richard Wright West, West & Wilkinson, P.O. Box 257, 2815 Huntington Avenue, Newport News, VA 23607; Mr. Richard Wright West West & Wilkinson P.O. Box 257 2815 Huntington Avenue Newport News VA 23607; Dear Mr. West: This is in response to your letter of January 2, 1974 requestin information concerning the legal permissibility of an automobile dealership furnishing private passenger motor vehicles with add-on gasoline tanks or modifying existing gasoline tanks.; Motor Vehicle Safety Standard No. 301, *Fuel System Integrity* establishes minimum performance requirements for motor vehicle fuel systems. Compliance with the level of performance mandated by the standard is enforced by Section 108(a)(1) of the National traffic and Motor Vehicle Safety Act which prohibits the manufacture, sale, delivery, or importation of vehicles or mtor vehicle equipment that do not meet the requirements of applicable safety standards. Therefore, if your client modified a motor vehicle fuel tank in such a manner that it no longer complied with Standard No. 301 and then offered it for initial sale for purposes other than resale he would be in violation of the Motor Vehicle Safety Act and would be subject to civil penalties of not more than $1,000 for each such violation. If, however, your client performed a fuel tank modification on a vehicle that was already owned by and in the possession of a buyer who purchased the vehicle for purposes other than resale, no violation of the Act could result. the installation of an add-on fuel tank would be considered a modification. Therefore, the fuel system would have to comply with Standard No. 301 with the add-on fuel tank considered as part of the system.; There are no Motor Vehicle Safety Standards applicable to add-o gasoline tanks since these are items of motor vehicle equipment and standard No. 301 restricts its application to motor vehicles. Section 113(e)(2) of the Motor Vehicle Safety Act, however, authorizes the Secretary of Transportation to determine whether or not an item of motor vehicle equipment contains a defect which relates to motor vehicle safety. If the Secretary finds that a safety-related defect exists, your client may be compelled to notify all purchasers of vehicles with the add-on fuel tanks of the attendant hazard.; The action of installing add-on gasoline tanks in motor vehicle exposes your client to the requirements of yet another safety regulation (49 CFR 567.7). If the vehicle in which he installs the fuel thank is a certified and complete vehicle that has not yet been purchased ingood faith for purposes other than resale, your client will be considered an alterer of the vehicle, and he must provide a certification that the vehicle as altered still conforms to the standards.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2943OpenMr. Heinz W. Gerth, Mercedes-Benz of North America, Inc., One Mercedes Drive, P. O. Box 350, Montvale, NJ 07645; Mr. Heinz W. Gerth Mercedes-Benz of North America Inc. One Mercedes Drive P. O. Box 350 Montvale NJ 07645; Dear Mr. Gerth: This responds to your letter of December 19, 1978, asking whether manually adjustable seat belt anchorage for the upper torso portion of a 3-point safety belt is permissible under Safety Standard No. 210, *Seat Belt Assembly Anchorages*. You state that this new anchorage is adjustable over a certain range and is intended to increase wearing comfort by providing a better 'fit' for all occupants.; We have reviewed the drawings and specifications enclosed with you letter and determined that the proposed adjustable anchorage design would not be precluded by Safety Standard No. 210 if the design meets the following two conditions: (1) the anchorage complies with the zone location requirements of the standard in any of the positions to which it can be adjusted, and (2) the anchorage complies with the strength requirements of the standard at all times, even when the adjusting mechanism (bolt) is in its loosened status. There is nothing in the standard that prevents the use of adjustable anchorages, per se.; From discussions with your engineers, we found that the proposed desig would require the use of a tool to tighten the adjusting bolt. We are concerned that this feature could reduce potential increases in belt use. For example, if driver A adjusts the belt anchorage to its lowest position, will driver B readjust the belt when he enters the car if the two drivers are of different sizes and the lowest position is uncomfortable for driver B? If the readjustment requires the use of a wrench to loosen and retighten the anchorage bolt, will driver B simply choose not to wear the belt? We believe that a manually adjusting anchorage that does not require the use of tools would be a preferable design in terms of potential seat belt use.; The agency is of course very interested in any seat belt design tha will increase comfort and convenience and, thereby, seat belt use. Therefore, we encourage innovative designs. Please keep us informed about the progress of your work on your new anchorage system.; The National Highway Traffic Safety Administration hereby grants you request for confidential treatment of the drawings included in your letter (enclosures 1, 2 and 4). We have preliminarily determined that the drawings and specifications contain privileged commercial information that is exempt from disclosure under 5 U.S.C. 552(b)(4).; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4194OpenMr. William Shapiro, Manager, Regulatory Affairs, Volvo Cars of North America, Rockleigh, NJ 07647; Mr. William Shapiro Manager Regulatory Affairs Volvo Cars of North America Rockleigh NJ 07647; Dear Mr. Shapiro: This responds to your letter concerning a newly designed Volvo chil safety seat. You stated that this child safety seat can be certified as complying with Standard No. 213, *Child Restraint Systems* (49 CFR S 571.213), when secured only by a vehicle lap belt, in the rearward-facing mode for infants and in the forward-facing mode for toddlers. In addition, you indicate that this child safety seat can be used in certain vehicle specific installations in Volvo vehicles, and that the vehicle specific installations 'provide a higher level of protection.' You asked this agency's opinion as to whether this new child safety seat is designed in due care to meet the minimum requirements of Standard No. 213 and whether it can be used in both the universal application that is, secured by only a lap belt and Volvo vehicle-specific modes.; With respect to your first question, the National Traffic and Moto Vehicle Safety Act (15 U.S.C. 1381 *et seq*.) provides no authority under which this agency can assure a manufacturer that its product has been designed in due care to comply with all applicable requirements or to otherwise 'approve' it. The Act establishes a process of self-certification under which a manufacturer is not required to submit a product to the agency for approval before sale, but simply to provide a certification to dealers and distributors that it does meet all applicable Federal motor vehicle safety standards. If that product does not in fact comply, the manufacturer must notify and remedy the noncompliance according to the Act, and it is in presumptive violation of it (and therefore subject to civil penalties) unless it can establish that it did not have reason to know in the exercise of due care that the product was noncompliant. The statute thus provides an affirmative defense to the manufacturer, but it is a defense that does not arise until there is a violation of the Act, and the burden is upon the proponent to establish it.; Under the Act a product must comply at the time of sale to its firs purchaser for purposes other than resale. This means that a manufacturer's responsibility to insure compliance does not end at the design stage, but extends through manufacture, distribution, and sale of the product. In this context whether a manufacturer has exercised due care in the design stage can be an irrelevant question if the noncompliance was caused by an error in the manufacturing process which should have been detected and corrected, for example. For these reasons we cannot provide the opinion that you seek.; With respect to your second question, Volvo can recommend its chil seat for use with a lap belt in vehicles other than those manufactured by Volvo and for vehicle- specific uses in Volvo cars. The preamble to the 1979 final rule establishing Standard No. 213 included the following statement: 'As long as child restraints can pass the performance requirements of the standard secured only by a lap belt, a manufacturer is free to specify other 'vehicle specific' installation conditions.' 44 FR 72131, at 72136, December 13, 1979. Therefore, Volvo can provide the vehicle-specific installation conditions for its child safety seat in Volvo automobiles. Please note that section S5.6 of Standard No. 213 requires manufacturers recommending vehicle-specific installations to provide step-by-step instructions for securing the child restraint in those particular vehicles, as well as providing such instructions for securing the child restraint when it is used in vehicles for which no vehicle-specific installation is recommended.; Please feel free to contact me if you have any further questions o need more information on this subject.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3651OpenMr. J. W. Lawrence, Manager, Compliance and Recall, Volvo White Truck Corporation, P.O. Box D-1, Greensboro, NC 27402-1200; Mr. J. W. Lawrence Manager Compliance and Recall Volvo White Truck Corporation P.O. Box D-1 Greensboro NC 27402-1200; Dear Mr. Lawrence: This responds to your letter concerning Safety Standard No. 101 *Controls and Displays*. You asked whether the standard's identification and illumination requirements are applicable to an optional windshield wiper control you are planning to make available on some heavy duty trucks.; By way of background information, the agency does not provide approval of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is up to the manufacturer to assure that its vehicles and equipment comply with applicable Federal motor vehicle safety standards. The following interpretation represents our opinion based on the facts provided in your letter. It also takes into account information provided in a follow-up telephone conversation with Edward Glancy of this office.; The standard wiper controls for the vehicles in question consist of tw knobs which independently control the left and right wipers. These controls provide both the on-off function and variable speed. According to your letter, these controls are identified and illuminated as required by the standard.; The proposed optional control, the specific subject of your letter would provide a time delay for windshield wiper operation during light mist conditions. The control would be a knob which, if turned to the left, would provide no pause, and if turned toward the right, would offer a variable time delay.; We are unable to agree with your suggestion that the control is no covered by Standard No. 101. As discussed below, Standard No. 101 requires that this control, like the standard controls, be identified and illuminated in accordance with the standard's requirements. Additional words or symbols may be provided for the purpose of clarity.; Section S5 of Standard No. 101 requires, among other things, that eac truck manufactured with any control listed in S5.1 or in column 1 of Table 1 meet the requirements of the standard for the location, identification, and illumination of such control. One of the controls listed by S5.1 is 'windshield wiper.' Also, 'windshield wiping system' is among the controls listed in column 1 of Table 1. The issue raised by your letter is therefore whether an optional control for intermittent wiper operation is within the meaning of 'windshield wiper' control and/or 'windshield wiping system' control. It is our interpretation that such a control is within the meaning of both terms.; Neither the term 'windshield wiper' control nor 'windshield wipin system' control is limited to specific wiper functions, such as on-off, variable speed, etc. Since a control for intermittent wiper operation controls one function of windshield wipers, it is a 'windshield wiper' control or 'windshield wiping system' control. Such a control is therefore subject to the standard's requirements for location, identification and illumination.; We would note that while section S5.2.1 and Table 1 require such control to be identified by the symbol specified for windshield wiping system controls, additional words or symbols may be used at the manufacturer's discretion for purposes of clarity. Since your vehicles would have three windshield wiper controls, you may wish to provide such additional words or symbols to explain the function of each.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1396OpenMr. Jim Lang, President, L and R Enterprises, P.O. Box 2201, Wichita Falls, TX 76307; Mr. Jim Lang President L and R Enterprises P.O. Box 2201 Wichita Falls TX 76307; Dear Mr. Lang: Since the questions raised in your letter of February 15, 1974, ar under the jurisdiction of the National Highway Traffic Safety Administration, Department of Transportation, we have taken the liberty of forwarding it to the General Counsel of that agency.; You can expect to hear directly from that office in the near future. Sincerely, Fred J. Emery, Director of the Federal Register |
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ID: aiam3201OpenMr. J. Kawano, General Manager, U.S. Representative Office, Toyota Motor Co., Ltd., One Harmon Plaza, Secaucus, NJ 07094; Mr. J. Kawano General Manager U.S. Representative Office Toyota Motor Co. Ltd. One Harmon Plaza Secaucus NJ 07094; Dear Mr. Kawano: This responds to your recent request for an interpretation concernin the proper designated seating capacity for the rear seat in several Toyota vehicle models (Corolla Sedan, Corolla Coupe, Corona Sedan and Starlet). You assert that the rear seat hip room in these models ranges from 39.4 inches to 42.6 inches, and ask whether the vehicles would qualify as having only two designated seating positions.; Under the strict measurement technique specified in the amende definition of 'designated seating position' (SAE J1100a), the Toyota vehicle models in question would have the hip room dimensions you state. This is due to the fact that the SAE procedure specifies that hip room is to be the minimum dimension of the seat cushion. The Toyota designs include wheel wells and contoured side paddings at the intersection of the seat back and seat cushion that establish the minimum dimension of the seat. However, these structures only extend out 4 to 5 inches (approximation) from the seat back. If the hip room of the rear seats is measured midway of the seat cushion, all of the designs have greater than 50 inches of hip room, and ostensibly should have three designated seating positions. Nevertheless, since according to the measurement technique specified in the definition these seats have substantially less than 50 inches of hip room, the agency must conclude that the rear seats could qualify as having only two designated seating positions. This opinion is accompanied with several candid remarks, however.; The effective hip room of the Toyota seat designs is much greater tha the approximately 40 inches that is obtained by the technical measuring technique specified in the definition. If two outboard occupants move their hips several inches forward from the seat back in these vehicle designs, the wheel-wells and contoured side paddings are no longer impediments and there is over 50 inches of hip room, as noted above. Moreover, the design of these rear seats is such that use of the center position is 'invited.' There is at least 10 to 12 inches of well-padded hip room at the center portion of the seat between the inboard ends of the two seat belt assemblies installed in the seats. The manufacturer has given no indication that this space is not intended for occupancy. The agency is also concerned that this center position has no belt assembly to secure a child restraint system, particularly since the rear- center seat is statistically the safest position in a vehicle.; Frankly, with the wide center space that is available in these rea seat designs, we do not believe the manufacturer has made a sincere attempt to indicate to vehicle occupants that the seats are intended for use by only two occupants. It would be a simple matter for the manufacturer to make this obvious by use of a fixed armrest or some other impediment to use of the position. Furthermore, we believe that this message can be given to occupants without otherwise compromising the design the manufacturer wishes to achieve. If the manufacturer does not in fact wish to market the vehicles as having three-passenger rear seats, we do not understand why wide, well-padded center positions are present.; Finally, I am enclosing a copy of an earlier interpretation whic discusses the measurement procedure included in the definition of 'designated seating position.' As that interpretation pointed out, the agency will not allow manufacturers to avoid the obvious intent of the definition by finding 'loopholes' in the specified measurement procedure. If designs such as those displayed in the Toyota vehicles persist, without some clear indication that the center position is not to be used, the agency may find it necessary to amend the definition to provide that the hip room measurement is to be taken at the midpoint of the seat cushion. We hope that manufacturers will voluntarily alter designs of this type to conform to the intent of the definition, so that such an amendment is not necessary.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4897OpenMrs. Debby Funk R.R. #1, Box 41A Shirley, IL 61772; Mrs. Debby Funk R.R. #1 Box 41A Shirley IL 61772; Dear Mrs. Funk: This responds to your letter of July 5, l99l, as followup to my letter of June 25. You have asked whether 'it would be illegal for the owner of a vehicle that has a center highmounted stop lamp to install an additional rear window brake light? (anywhere in the back window?)' The answer is that it would not be illegal under Federal law for a vehicle owner to install an additional stop lamp anywhere in the back window, providing that all modifications were performed by the owner. However, the legality of the modification would still be subject to State law. You have also asked 'What is F.M.V.S.S. 108?' That is Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment. It can be found in Title 49 Code of Federal Regulations, as Section 571.108. If you have further questions, please don't hesitate to write. Sincerely, Paul Jackson Rice 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.