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: aiam0312OpenMr. John L. MacLaren, General Manager, Western Safety Devices Company, 4041 Hollis Street, Emeryville, CA 94608; Mr. John L. MacLaren General Manager Western Safety Devices Company 4041 Hollis Street Emeryville CA 94608; Dear Mr. MacLaren: In response to your letter of March 10, 1971, to Mr. Douglas W. Toms Administrator, National Highway Traffic Safety Administration, concerning Federal Motor Vehicle Safety Standard No. 121, Air Brake Systems, Trucks, Buses and Trailers, the following information is offered.; >>>1. Standard No. 121 applies only to new vehicles manufactured on o after January 1, 1973.; 2. Federal Motor Vehicle Safety Standard No. 121 does not preclude th use of a dashboard-mounted control for the tractor protection valve.; 3. Standardization of a dashboard- mounted control valve is no contemplated at the present time.; 4. A petition requesting reconsideration of the requirements for parking brake control valve in S5.4.6 has been received and is being considered at the present time. The decision in response to this and other petitions will be published in the *Federal Register* in the near future.<<<; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam4351OpenMr. David O. Johnson, 135 Karen Drive, Washington, PA 15301; Mr. David O. Johnson 135 Karen Drive Washington PA 15301; Dear Mr. Johnson: This responds to your April 22, 1987, letter asking about the legalit of transporting people in fifth wheel trailers. The National Highway Traffic Safety Administration is responsible for promulgating safety standards for the manufacture and sale of new motor vehicles. The use of a motor vehicle, such as a trailer, is a matter over which we have no jurisdiction.; Because the legality of carrying people in trailers might be governe by State law, we suggest you contact State officials with your questions. Additionally, questions you might have about the operation of interstate motor carriers should be directed to Mr. Tom Kozlowski of the Office of Motor Carrier Standards (Room 3403), Federal Highway Administration, at this address.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3494OpenRichard F. Starkey, Esq., Assistant General Counsel, Fruehauf Corporation, 10900 Harper Avenue, P.O. Box 238, Detroit, MI 48232; Richard F. Starkey Esq. Assistant General Counsel Fruehauf Corporation 10900 Harper Avenue P.O. Box 238 Detroit MI 48232; Dear Mr. Starkey: This responds to your recent letter to Mr. Kratzke of my staf concerning the requirements of Federal Motor Vehicle Safety Standard No. 120 (49 CFR S571.120). Specifically, you asked if retreaded tires could be mounted on new trucks and trailers, and what requirements those tires would have to meet.; Retreaded tires can be mounted on new trucks and trailers withou violating Standard 120. For your information, I have enclosed a copy of a 1978 interpretation concerning Standard 120 which explains that retreaded tires can be mounted on new trucks and trailers in compliance with the standard. The only requirements those tires would have to meet is that the sum of maximum load ratings for the tires would have to be at least equal to the gross axle weight rating of the axle to which they were fitted, as specified in section S5.1.2 of the Standard 120. As explained in the attached letter, there is no requirement that the retread meet the requirements of Standard 119 because those requirements are inapplicable to retreads. Further, there is no requirement that the retreads have the DOT symbol.; If you have any further questions, please contact Mr. Kratzke at (202 426- 2992.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1153OpenMr. Richard T. Ford, Hayden, Smith, Ford & Hays, 1215 Security Bank Building, Fresno, CA 93721; Mr. Richard T. Ford Hayden Smith Ford & Hays 1215 Security Bank Building Fresno CA 93721; Dear Mr. Ford: This is in reply to your letter of May 21, 1973, forwarding to us you second attempt to compose a letter that will conform to Part 577, Defect Notification, for a defect involving the lighting in boat trailers manufactured by V/M Custom Boat Trailers. We responded to an earlier letter from you on May 16, 1973.; Section 577.6 prohibits the making of any statement in the notificatio that either states or implies that the problem discussed is not a defect, or that it does not relate to motor vehicle safety. As we indicated to you in our letter of May 16, we considered your statement, 'The defect on those trailers . . . does not affect the mechanical operation of said trailer except insofar as the lighting is inefficient as installed according to the U.S. Department of Transportation' to be prohibited by section 577.6. The additional phrase, 'This statement is one of fact only and is not intended to be a disclaimer which is prohibited by section 577.6 of the Act', which you have now inserted, does not remedy that deficiency. The regulation states that such a statement may not be made at all, it does not allow it to be made and denied.; Our objection to the statement is with your description of the defec as an 'inefficiency' according to the Department of Transportation. This safety related defect results, rather, from violations of law which require your client's products to meet minimim (sic) safe levels of performance. We recommend that rather than attempt once again to rewrite your statement, and risk violation of the regulation, you delete it entirely, and send the notification to purchasers forthwith.; In other respects your notification appears to conform to Part 577. Sincerely yours, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4701OpenMr. Hank Kmiecik Steerable Carriages P.O. Box 211 Little York, NJ 08834; Mr. Hank Kmiecik Steerable Carriages P.O. Box 211 Little York NJ 08834; "Dear Mr. Kmiecik: This responds to your January 5, 1990 lette requesting our review of your rear wheel steering system for trucks, buses and special application vehicles. This system is intended to replace one rear axle on these vehicles, and when activated, enables the axle to rotate slightly on its vertical axis. It is intended to improve the maneuverability of these vehicles in low-speed situations such as making sharp turns. During a February 9, 1990 telephone conversation with David Greenburg of this office, you explained that, while your product uses air from the vehicle's compressed air suspension system to operate the axle, it is isolated from the air brake system. You also explained that, as a result of this design, a failure in the air system connected to your product would not affect the operation of the vehicle's braking system. By way of background information, NHTSA has no authority to approve, endorse or offer assurances of compliance for any motor vehicle or item of motor vehicle equipment. Instead, the National Traffic and Motor Vehicle Safety Act of 1966 makes manufacturers of motor vehicles or items of motor vehicle equipment responsible for certifying that each of its products conforms with all applicable safety standards. In this instance, there are no specific provisions in the safety standards that set forth requirements for steerable rear axles. Thus, your company as the manufacturer of such a product would not have to certify that a steerable rear axle complies with any safety standard before offering it for sale to the public. However, the addition of a steerable rear axle to a vehicle before its first sale to the public could affect the vehicle's compliance with various safety standards. In such a case, the manufacturer or alterer that installed this product on a new vehicle would have to certify that the vehicle, with the steerable rear axle installed, complied with all applicable safety standards. For example, installation of the steerable axle could affect the vehicle's compliance with the applicable braking standard (Federal Motor Vehicle Safety Standard No. 121, Air brake systems) or the tire and rim selection standard (FMVSS No. 119, New pneumatic tires for vehicles other than passenger cars). Of course, you will need to consider other safety effects that operation of the steerable axle system could have. Among these considerations would be ensuring that the trailer's gross axle weight rating (GAWR) is not exceeded when the steering system is in operation and the the trailer is supported by only the steerable axle instead of by both the steerable and fixed axles. Although we do not have any standards that directly apply to your product, we do have several statutory provisions that could affect it. Manufacturers of motor vehicle equipment such as your steerable rear axle are subject to the requirements in sections 151-159 of the Vehicle Safety Act (15 U.S.C. 1411-1419) concerning the recall and remedy of products with defects related to motor vehicle safety. The Safety Act specifies that if either your company or this agency determines that a safety-related defect exists in your product, your company as the manufacturer must notify purchasers of the safety-related defect and must either: (1) repair the parts so that the defect is removed, or (2) replace the parts with identical or reasonably equivalent parts which do not have a defect. Whichever of these options is chosen, the manufacturer must bear the full expense and cannot charge the owner for the remedy if the equipment was purchased less than 8 years before the notification campaign. In addition, the use of your product could be affected by section 108(a)(2)(A) of the Vehicle Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits any manufacturer, dealer, distributor, or repair business from knowingly 'rendering inoperative' any device or element of design installed on or in a vehicle to comply with an applicable safety standard. To avoid a 'rendering inoperative' violation, the above-named parties should examine the proposed installation instructions for the steerable rear axle and compare those instructions with the requirements of our safety standards, to determine if installing the steerable rear axle in accordance with those instructions would result in the vehicle no longer complying with the requirements of the safety standards. If the installation of the steerable rear axle would not result in a rendering inoperative of the vehicle's compliance with the safety standards, the product can be installed by dealers, distributors, and repair shops without violating any Federal requirements. The Safety Act places the initial responsibility for determining whether the installation of this steerable rear axle on vehicles would result in a 'render inoperative' violation on your company. This agency may reexamine your determination in the context of an enforcement action. For your information, I have enclosed a copy of an information sheet for new manufacturers of motor vehicles and new motor vehicle equipment. This sheet gives a brief description of our regulations and explains how to obtain copies of those regulations. You should also be aware that State laws may apply to your product. I hope this information is helpful. Please feel free to contact this office if you have any further questions or need additional information. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosure"; |
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ID: aiam1503OpenMr. Merle O. Robberts, Controller, Hellstar Corporation, 1600 N. Chestnut, Wahoo, NE 68066; Mr. Merle O. Robberts Controller Hellstar Corporation 1600 N. Chestnut Wahoo NE 68066; Dear Mr. Robberts: This is in response to your letter of May 13, 1974, requestin information concerning the existence of any Federal Motor Vehicle Safety Standards applicable to auxiliary fuel tanks.; The National Highway Traffic Safety Administration has promulgated n motor vehicle safety standard relating to auxiliary fuel tanks. There is, however, a safety standard which imposes performance requirements upon motor vehicles with regard to their fuel systems. Thus if installation of the auxiliary tank is accomplished prior to the first purchase of the vehicle for purposes other than resale causing the vehicle's fuel system not to be in compliance with the applicable safety standard, the person installing the tank or offering the vehicle for sale would be in violation of S108(a)(1) of the National Traffic and Motor Vehicle Safety Act. That would make the installer or seller subject to civil penalties of up to $1,000 for each violation.; The National Traffic and Motor Vehicle Safety Act authorizes th Secretary of Transportation to make a determination as to whether or not an item of motor vehicle equipment contains a defect which relates to motor vehicle safety. If he finds that a safety-related defect exists, he may compel the manufacturer to notify purchasers of the hazard. Therefore, even though auxiliary fuel tanks are not the subject of a standard, they still must be safely designed.; For your information, I have enclosed a copy of the Federal Safet Standard relating to motor vehicle fuel systems.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1016OpenMr. J. C. Eckhold, Director, Automotive Safety Office, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. J. C. Eckhold Director Automotive Safety Office Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Eckhold: This is in reply to your letter of February 16, 1973, concerning th safety standard applicable to the sling for the upper torso belt used in Ford's 1974 model restraint system.; The schematic drawing attached to your letter shows that the slin attaches to the roof rail and serves the function of an upper torso belt anchorage. We agree with you that the sling is subject to the requirements of Standard No. 210 and not to the requirements of Standard No. 209. Although the sling is made of fabric webbing, its function is that of an anchorage and it is therefore subject to the anchorage standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4214OpenMr. Donald L. Anglin, 706 Rose Hill Drive, Charlottesville, VA 22901; Mr. Donald L. Anglin 706 Rose Hill Drive Charlottesville VA 22901; Dear Mr. Anglin: Thank you for your letter of August 7, 1986, concerning th applicability of our regulations to the repair of fuel tanks. You specifically asked whether our regulations prohibit the repair of automotive fuel tanks made of plastic. As explained below, a dealer or motor vehicle repair shop can make repairs to plastic and other types of vehicle fuel tanks.; Manufacturers must certify that their new vehicles comply with al applicable safety standards. Federal Motor Vehicle Safety Standard No. 301, *Fuel System Integrity* sets performance requirements for new vehicles with a gross vehicle weight rating of 10,000 pounds or less. Manufacturers of these vehicles are free to use fuel tanks made of any type of material, such as metal or plastic, as long as the fuel system can meet all of the performance requirements of the standard.; Repair of a fuel tank in a new vehicle, which, for example, sustaine damage in shipment, would be affected by Standard No. 301. If a fuel tank is repaired prior to a new vehicle being sold for the first time to a consumer, the person making the repairs would be considered a vehicle alterer under our regulation on certification (Part 567, a copy of which is enclosed). As an alterer, the person must certify that the fuel system, as altered, continues to comply with all of the applicable requirements of Standard No. 301.; After a vehicle is first sold to a consumer, repairs to a vehicle ar potentially affected by section 108(a)(2)(A) of the Vehicle Safety Act. That section prohibits commercial businesses from knowingly tampering with safety equipment installed on a vehicle in compliance with our standards. However, the agency has not applied the prohibition of that section to the repair of a fuel tank which has been previously installed in a vehicle and damaged in use. The agency has considered the event that damaged the fuel tank and not any subsequent action by a person repairing the damaged fuel tank in a used vehicle, as the event which rendered inoperative the compliance of the fuel tank with the standard. Thus, there is no Federal regulation which would prohibit the repair of a fuel tank which has been damaged in use.; In addition, section 108(a)(2)(A) does not affect vehicle owners, wh may themselves alter their vehicles as they please, so long as they adhere to all State requirements. Under Federal law, the owner may repair fuel tanks regardless of whether the repairs adversely affect the fuel system. The agency, however, urges vehicles owners not to take actions that would degrade the performance of required safety features. Please note also that individual States govern the operational use of vehicles by their owners. Therefore, it is within the authority of the States to preclude owners from repairing the fuel systems in their vehicles.; If you need further information, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1446OpenMr. Bruce J. Motyka, 2030 Laura Lane, Des Plaines, IL 60018; Mr. Bruce J. Motyka 2030 Laura Lane Des Plaines IL 60018; Dear Mr. Motyka: This is in reply to your letter of March 11, 1974, asking fo suggestions regarding problems you have experienced with your pickup truck-camper unit.; It appears from your letter that no violations of Federal requirement have occurred. Motor Vehicle Safety Standard No. 126 and its companion Consumer Information requirement (49 CFR S 575.103) about which we wrote to you through Senator Percy's office did not become effective until January 1, 1973, well after the time you bought your vehicle. Moreover, it is not correct to characterize the dealer who sold you the unit as a 'final-stage manufacturer.' Under NHTSA requirements a pickup truck is a completed vehicle, and a person who installs a slide-in camper into the cargo area of a truck does not become a manufacturer. While this is not the case with chassis-mount campers, it is with respect to slide-in campers.; I suggest that if you wish to proceed further you consult an attorney who would be able to best assess your chances of success in civil litigation. The dealer's employee who told you that the 'GVW plate meant nothing' was mistaken. The weight ratings provided on the plate represent the manufacturer's representation of the maximum safe weight of a fully loaded vehicle.; You might wish to examine the labels attached, pursuant to Standard No 126 and 49 CFR S 575.103, to later models of both the pickup truck and camper you purchased. It is possible that those models and the ones you purchased are not substantially different. If that is the case the information on the labels can provide an indication of the extent that the weight ratings were exceeded by installation of the camper unit in question.; While I regret we cannot be of further assistance I wish you success i your efforts to solve this problem.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3181OpenMr. W. G. Milby, Manager, Engineering Services, Blue Bird Body Company, P. O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Manager Engineering Services Blue Bird Body Company P. O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to your October 8, 1979, letter and follow-up meeting i which you ask several questions about the compliance of your school buses with Standard No. 221, *School Bus Body Joint Strength*. In your letter, you ask about four separate joints and ask whether they would be required to comply with the standard.; As you know, the standard applies to any joint of a body panel tha encloses bus body space and a body structure member. An exception from the standard exists for those joints that connect maintenance access panels. In our meeting with you, we stated the agency's objection to the existing industry practice involving maintenance access panels, and further stated that the agency was contemplating rulemaking to restrict the maintenance access panel exception.; Responding directly to the four joints that you reference in you letter, you first ask whether the contact point between the headlining panel and the spring clip is a joint subject to the standard. A spring clip is entirely enclosed within a bus wall. Its function is to aid in holding the body panel in place while the rivets or adhesives are being applied. It serves no function beyond that. The agency does not believe that a spring clip is either a body structure member or a body panel enclosing occupant space. Accordingly, the joint of this clip and any other body member is not a joint subject to the standard.; In your second question, you ask whether the joint between th headlining panel and the headlining panel positioning tab is a joint subject to the standard. The positioning tab is a device that is approximately two inches long and contacts the headlining panel in two places between the bus body bows. The purpose of this tab, is to prevent buckling of the headlining panel between the two bows. The agency concludes that positioning tabs are body structure members. Therefore, if they contact a body panel at its edge, the intersection of these two components creates a joint subject to the standard.; Your third question asks whether an extruded aluminum sash assembl must comply with the standard. You state in your letter that this assembly is part of the window and, therefore, exempt from the requirements. The aluminum sash assembly to which you refer is an add-on device above the window found in your larger buses to provide more headroom. The agency concludes that this device has no function as a part of the window but merely is a trim panel that serves to cover part of the bus sidewall. Accordingly, the joint connecting this panel to the remainder of the bus structure would be required to comply with the standard.; Finally, you ask whether the joint between a positioning angle and headlining panel must comply with the joint strength requirements. A positioning angle is a body structure member that runs from bow to bow and supports the edge of the headlining panel to prevent buckling. The agency concludes that this positioning angle is a body structure member and its connection with a body panel is a joint subject to the standard's requirements.; Sincerely, Frank Berndt, 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.