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: aiam1641OpenMr. M. J. Denholm, Director of Engineering, Power Controls Division, Midland-Ross Corporation, 490 S. Chestnut Street, Owosso, MI 48867; Mr. M. J. Denholm Director of Engineering Power Controls Division Midland-Ross Corporation 490 S. Chestnut Street Owosso MI 48867; Dear Mr. Denholm: This responds to Midland-Ross' October 8, 1974, clarification of it February 8, 1974, petition for an amendment of S5.1.2.1 and S5.2.1.2 of Standard No. 121, *Air brake systems*, that would establish separate air reservoir volume requirements for several brake chamber types generally available in the air brake component market. You point out that Midland-Ross was referring to chamber stroke and not chamber diameter as the chamber dimension which could affect the safety of a brake system. You also requested that we adopt SAE Standard J10b instead of J10a as our specification of a reservoir that 'withstands' certain internal hydrostatic pressure.; In our denial of your petition, we did understand your point tha additional stroke could be discouraged by a reservoir capacity requirement based on chamber size at maximum travel of the piston or diaphragm. We found that the stopping distance requirements in effect mandate the installation of high performance components, and we do not anticipate a safety problem. If a safety problem does arise in the future, we would consider a modification of S5.1.2.1 and S5.2.1.2.; SAE Standard No. J10b is identical to J10a in its requirement that n rupture or permanent circumferential deformation of the reservoir exceed one percent. Therefore, for purposes of S5.1.2.2 and S5.2.1.3, we are adopting SAE J10b as our specification of 'withstand' until we undertake further rulemaking.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam1354OpenMr. Jack R. Gilstrap, Southern California Rapid Transit District, 1060 South Broadway, Los Angeles, CA 90015; Mr. Jack R. Gilstrap Southern California Rapid Transit District 1060 South Broadway Los Angeles CA 90015; Dear Mr. Gilstrap: We are enclosing an Experimental Device Permit authorizing you to equi the buses described in your letter of December 11 with a warning system which will flash the clearance and sidemarker lamps in the event of an emergency. The permit will expire on December 31, 1974.; Please supply us with the data on the number and types of crime involving your buses during the calendar years 1972 and 1973. This information can later be compared with that of similar periods during 1974 when the buses are equipped with the experimental lamps. We would also like to have a copy of the outline of your plan for evaluating the effectiveness of the new system.; A copy of the drawing or wiring diagram of the installation would als be of interest to us, particularly the safeguards taken against the possibility of inadvertent activation.; Very truly yours, Warren M. Heath, Commander, Engineering Section |
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ID: aiam3369OpenMr. Stephen E. Mulligan, International Harvester, 401 North Michigan Avenue, Chicago, Il 60611; Mr. Stephen E. Mulligan International Harvester 401 North Michigan Avenue Chicago Il 60611; Dear Mr. Mulligan: This is in response to your letter of October 1, 1980, in which you as whether compliance with 49 CFR 567, Certification, will satisfy the requirements of S4.3 of Federal Motor Vehicle Safety Standard No. 115, 49 CFR 571.115.; Section 4.3 of Federal Motor Vehicle Safety Standard No. 115 require that the vehicle identification number (VIN) 'appear clearly and indelibly upon either a part of the vehicle other than the glazing that is not designed to be removed except for repair or upon a separate plate or label which is permanently affixed to such a part.' S4.3.1 requires each character to appear in a capital, sans serif typeface. In the case of passenger cars and trucks of 10,000 pounds or less GVWR, each character must have a minimum height of 4 mm. S4.4 specifies that the VIN for passenger cars and trucks of 10,000 pounds or less GVWR shall be located within to passenger compartment.; Section 567.4 of Part 567, Certification (49 CFR 567), requires tha the certification label be permanently affixed to the vehicle, and display the vehicle identification number. Consequently, for all vehicles except passenger cars and trucks of 10,000 pounds or less GVWR, compliance with S 567.4 of Part 567 would also effect compliance with S4.3 of Standard No. 115 so long as capital, sans serif typeface was used.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2981OpenMr. Mark E. Grayson, E. Grayson, Executive Assistant for Government Affairs, National Tire Dealers & Retreaders Association, Inc., 1343 L Street, N.W., Washington, DC 20005; Mr. Mark E. Grayson E. Grayson Executive Assistant for Government Affairs National Tire Dealers & Retreaders Association Inc. 1343 L Street N.W. Washington DC 20005; Dear Mr. Grayson: This is in response to your letter of March 2, 1979, in which yo request clarification of several points relating to the Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104), and the record retention requirements applicable to tire retreaders.; You inquire first as to the obligations of tire dealers under the UTQ regulation. As explained more fully in our recent letter to Mr. Tony Hylton of your organization, the UTQG regulation places the responsibility for supplying tire grading information on vehicle and tire manufacturers and tire brand name owners. These parties must make their own arrangements with tire distributors and dealers to assure that the required tire grading information reaches tire purchasers.; You ask whether bias-ply tires manufactured abroad prior to April 1 1979, but imported into the United States after April 1, must be labeled in accordance with the requirements of paragraph (d)(1)(i)(B) of the UTQG regulation (49 CFR 575.104(d)(1)(i)(B)). Paragraph (d)(1)(i)(B), which becomes effective on April 1, 1979 for bias-ply tires, applies to bias- ply tires manufactured after that date. The date of manufacture rather than the date of importation is controlling in determining whether tires fall within the tread labeling requirements of the UTQG regulation.; You also ask whether tires to which the UTQG labeling requirement apply can be imported into the United States without the required tread labels, provided adequate labels are attached at the tires' point of sale. The purpose of the UTQG labeling requirements is to provide information to assist consumers in tire purchasing decisions. Therefore, the tread labeling requirements of the regulation would be satisfied if labels are attached at the dealership prior to the time the tires are offered for sale. However, manufacturers and brand name owners should be cautioned that they will be held responsible should the dealer incorrectly label the tires or neglect to attach the required labels.; Finally, you inquire whether manufacturers of retreaded tires mus retain tire registration records compiled pursuant to Part 574, *Tire Identification and Recordkeeping* (49 CFR Part 574), in view of the recent exemption of retreaders from the registration requirements of that part. While the registration requirements of Part 574 no longer apply to the sale of retreaded tires, section 574.7(d) (49 CFR 574.7(d)) nonetheless requires that previously compiled records on retreaded tires be maintained for a period of not less than three years from the date the information was recorded by the tire manufacturer or his designee.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam4156OpenMr. Rudy Valdez, Product Manager, Mr. Gasket Company, 19914 South Via Baron St., Compton, CA 90220; Mr. Rudy Valdez Product Manager Mr. Gasket Company 19914 South Via Baron St. Compton CA 90220; Dear Mr. Valdez: This is in reply to your letter of May 1, 1986, with reference t Federal Motor Vehicle Safety Standard No. 108 *Lamps, Reflective Devices, and Associated Equipment*.; Your first question concerns the liability of an aftermarket splas guard installed behind the rear wheels which would incorporate a decorative light, the illustration you enclose shows the word 'Ford' illuminated. Although the lighting equipment that is required by Standard No. 108 must be located on a rigid part of the vehicle, there is no such requirement for aftermarket equipment such as the device that you propose. If an item of aftermarket equipment is installed before the sale of a new vehicle to its first owner, such an item is permissible under Standard No. 108 provided that it does not impair the effectiveness of the required lighting equipment, but no matter when it is installed, it would be subject to regulation by any State in which a vehicle so equipped is registered or operated. We are not familiar with State laws on this subject, and recommend that you contact the Department of Motor Vehicles in States where you intend to sell your device.; Your second question asks for information on the new center hig mounted stop lamp, saying that you have seen some that do not appear to meet Federal requirements. You ask whether we will require retrofitting of vehicles. The new lamp was optional for passenger cars manufactured on or after August 1, 1984, and mandatory for those manufactured on or after September 1, 1985. The coverage of Standard No. 108 also extends to aftermarket items that are manufactured to replace original equipment center high mounted stop lamps, but there are no Federal requirements for lamps intended for use on cars that were not originally manufactured with them. We encourage manufacturers to meet the Federal specifications as closely as possible, however, and I enclose a copy of the regulation for your information. We have no authority to require retrofitting of vehicles.; I hope that this answers your questions. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3693OpenMr. Jerry G. Stapp, Jim Martin Tire, 522 Park Street, P.O. Box 2696, Jacksonville, FL 32203; Mr. Jerry G. Stapp Jim Martin Tire 522 Park Street P.O. Box 2696 Jacksonville FL 32203; Dear Mr. Stapp: This responds to your letter to Mr. Kratzke of my staff asking abou this agency's regulations applicable to regrooved tires. Specifically, you asked if a foreign casing must have a DOT symbol on the sidewall in order to be regrooved, what requirements apply to regrooved tires intended for a dealer's own use, and whether there are any restrictions on the use of regrooved tires in particular wheel locations.; 49 CFR Part 569 (copy enclosed) specifies the requirements which mus be met by all regrooved tires, except those intended solely for export and so tagged or labeled. The mechanics of importing casings for regrooving are explained in a previous letter of interpretation issued by the agency (copy enclosed). Once the casing is inside the customs territory of the United States, Part 569 specifies that the casing must be labeled 'regroovable' on both sidewalls. This marking cannot be added to the sidewall by a regroover before regrooving, but must have been placed there by the original manufacturer or a prior retreader. It seems unlikely that foreign manufacturers or retreaders would so label their tires. This means that few, if any, imported foreign casings may legally be regrooved. As explained in the enclosed letter, there is no requirement that the *DOT symbol* appear on the sidewall of casings in order for the casings to be regrooved.; The requirements of Part 569 apply to all tires regrooved in the Unite States, and apply equally to tires regrooved for sale to another party and to tires regrooved for the regroover's own use (Part 569.7). Each violation of those requirements could subject the offender to a $1,000 civil penalty. Each illegally regrooved tire would be treated as a separate violation.; With respect to your question about restrictions on the application an wheel position of a regrooved tire, this agency has no regulations. The bureau of Motor Carrier Safety of the Federal highway Administration has issued a regulation applicable to carriers used in interstate commerce. That regulation prohibits the use of regrooved tires above a certain load-carrying capacity on the front wheels of trucks and truck tractors. If you need further information concerning this subject, please contact Mr. Kenneth L. Pierson, Director, Bureau of Motor Carrier Safety, Federal Highway Administration, Washington, D.C. 20590.; Should you have any further questions regarding regrooved tires, pleas feel free to contact Mr. Kratzke at (202) 426-2292.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0816OpenMr. Robert F. Farrelly, Safety Products, Inc., 331 East Brooks Road, Suite 11, Memphis, TN 38109; Mr. Robert F. Farrelly Safety Products Inc. 331 East Brooks Road Suite 11 Memphis TN 38109; Dear Mr. Farrelly: This is in reply to your letter of July 17, 1972, in which you as whether a person who installs on new vehicles a device you manufacture called the Safti-Stabilizer is required to recertify the vehicle.; A person will be required to recertify a new, completed vehicle if h modifies it is such a manner that he becomes a 'manufacturer' under the National Traffic and Motor Vehicle Safety Act. A person will be considered a manufacturer if the modifications he performs produce significant changes in the vehicle's configuration or purpose. while this determination is generally made on a case by case basis, examples of modifications which the NHTSA has considered to be 'manufacturing' include the addition of new axles, or the changing of a completed truck van into a motor home.; The NHTSA has taken the position, in close cases, that it will accept good-faith determination of a person modifying new vehicles as to whether the modification is of such a nature so as to make that person a manufacturer. Based on the information you have provided to us, it appears that the installation of the Safti-Stabilizer does not significantly change the vehicle's configuration or purpose. Consequently, we would accept a determination that the installation of the Safti-Stabilizer does not constitute remanufacturing, and a person who installs the device on new vehicles need not recertify them.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1704OpenMr. James P. Coughlin, Vice President - Marketing, Bell Helmets Inc., 2850 Long Beach, CA 90806; Mr. James P. Coughlin Vice President - Marketing Bell Helmets Inc. 2850 Long Beach CA 90806; Dear Mr. Coughlin: This responds to your letter of November 14, 1974, asking whether FMVS 218 applies to helmets intended for use by riders of moped cycles.; The answer to your question is yes. Standard 218 applies to 'helmet designed for use by motorcyclists and other motor vehicle users.' A 'moped' is a 'motor vehicle' (15 U.S.C. 1391), it is also a 'motorcycle,' and specifically a 'motor-driven cycle' (49 CFR 571.3). Since a motorcyclist is any rider of a motorcycle, Standard 218 clearly applies to helmets designed for use by motor driven cycle riders.; As you are probably aware, the States and their political sudivision have jurisdiction over the circumstances under which helmets must be worn. Thus a State could conceivably exclude motor-driven cycles from the coverage of its helmet use law. But this would not affect the obligation of your company to manufacture to comply with Standard 218 all helmets which you intend to be used in connection with the operation of a motor vehicle.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3739OpenMr. Gary Fulmer, Benchmark Research, Inc., 9921 NE 135th Pl., #1, Kirkland, WA 98033; Mr. Gary Fulmer Benchmark Research Inc. 9921 NE 135th Pl. #1 Kirkland WA 98033; Dear Mr. Fulmer: This responds to your letter asking whether an adapter you plan t manufacture for attachment to child restraint systems must be tested for compliance with Federal Motor Vehicle Safety Standard No. 213, *Child Restraint Systems* (49 CFR 751.213). The adapter you plan to manufacture snaps onto the bottom of the tube frame of child restraints, and unfolds legs and wheels to convert the car seat into a stroller. Your device does not need to comply with the requirements of Standard No. 213. However, you might wish to test it to ensure that it does not constitute a safety-related defect when attached to a child restraint and for purposes of product liability.; Section S4 of Standard No. 213 defines a child restraint system as 'an device designed for use in a motor vehicle to restrain, seat, or position children who weigh not more than 50 pounds.' The stroller adapter you plan to produce is not designed to perform any of these functions, and therefore is not a child restraint within the meaning of Standard No. 213. Because the device is not a child restraint system, it need not comply with any of the requirements of Standard No. 213.; One requirement which might be applicable to the use of your device i set forth in 15 U.S.C. 1397(a)(2)(A), which states '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 or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard...' This could be important if the attachment of your stroller adapter to a child restraint system caused the child restraint system to no longer comply with the requirements of Standard No. 213. It appears from your letter, however, that the purchaser of your device would attach it to a child restraint, and not a manufacturer or dealer. The statutory prohibition is not violated when a purchaser attaches a device to an item of motor vehicle equipment. Hence, if my understanding is correct, this would not present any difficulties for your company.; There are two possible reasons which might lead you to try to test thi adapter to learn if it affects the performance of child restraint systems to which it is attached. First, if the attachment of your adapter causes the child restraint to provide a lower level of safety, or if all or part of the adapter were to separate from the child restraint in a crash situation, the adapter might well be found to contain a defect which relates to motor vehicle safety. Sections 151-154 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1411-1414) require that when an item of motor vehicle equipment contains a safety-related defect, the manufacturer of the item must recall and repair or replace the defective equipment without charge to the purchaser.; Second, you may wish to consult an attorney for advice on potentia product liability issues which would arise from attaching your adapter to certified child restraint systems. It is possible that some testing of your adapter attached to a child restraint system in a crash situation would be helpful in the event of a product liability suit.; Should you need any further information on this subject, please do no hesitate to contact me.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4506OpenJay D. Starling, Manager Strategic Business Development ARCO Solar, Inc. 4650 Adohr Lane P. O. Box 6032 Camarillo, CA 93010; Jay D. Starling Manager Strategic Business Development ARCO Solar Inc. 4650 Adohr Lane P. O. Box 6032 Camarillo CA 93010; "Dear Mr. Starling: I am writing in response to your letter tha requested the National Highway Traffic Safety Administration's (NHTSA) interpretation as to whether the ARCO Solar 'G-33 Charge Saver' is an item of 'motor vehicle equipment', as defined in Section 102(4) of the National Traffic and Motor Vehicle Safety Act of 1966. I regret the delay in responding to your inquiry. The product literature you enclosed with your letter describes the 'G-33 Charge Saver' as a '12 Volt car battery maintenance system, designed to overcome natural battery self-discharge and drain from constant electrical loads...It is operated by simply placing it in sunlight on the dashboard and plugging it into the car lighter whenever the vehicle is parked.' It also claims that the 'G-33 Charge Saver' can help to: 'Extend Battery Life Prevent Dead Batteries Provide Quick Starts.' Section 102(4) of the National Traffic and Motor Vehicle Safety Act defines, in 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' the agency has looked at the following two factors: first, whether the item has no ostensible purpose other than use with a motor vehicle and second, whether it is intended to be used principally by ordinary users of motor vehicles. From the product literature provided, the ARCO Solar 'G-33 Charge Saver' is advertised for use with a motor vehicle and appears to be marketed for the ordinary user of motor vehicles, with emphasis on the ease of installation of the charge saver. We would therefore consider your solar powered battery charger to be a vehicle accessory and thus an item of motor vehicle equipment covered by the Vehicle Safety Act. If the ARCO Solar 'G-33 Charge Saver' will be installed in new or used vehicles by a commercial business, Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act could affect your product. That section of the Act requires manufacturers, distributors, dealers and motor vehicle repair businesses to ensure that they do not knowingly render inoperative any device or element of design installed on or in a motor vehicle in compliance with an applicable Federal Motor Vehicle Safety Standard (FMVSS). These businesses could sell your product, but could not install it if the installation would adversely affect the vehicle's compliance with any FMVSS. In the first instance, it would be the responsibility of these entities to determine whether there is any possibility of such an effect. The prohibitions of Section 108(a)(2)(A) do not apply to the actions of a vehicle owner in adding to or otherwise modifying his or her vehicle. Thus, a vehicle owner would not violate the Act by installing the ARCO Solar 'G-33 Charge Saver' even if doing so would adversely affect some safety feature in his or her vehicle. The Act also requires the recall and remedy of motor vehicles and motor vehicle equipment determined to contain a defect related to motor vehicle safety. If you or NHTSA determine that the ARCO Solar 'G-33 Charge Saver' contains such a defect, you must recall and repair or replace the item without charge to the purchaser. I am enclosing a copy of the Act, and an information sheet describing how you can obtain copies of our motor vehicle safety standards and any other NHTSA regulation. If you have any further questions, please let me know. Sincerely, Erika Z. Jones Chief Counsel"; |
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Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.