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: aiam4380OpenL.M. Short, Chief, Enforcement Services Division, Department of California Highway Patrol, P.O. Box 898, Sacramento, CA 95804; L.M. Short Chief Enforcement Services Division Department of California Highway Patrol P.O. Box 898 Sacramento CA 95804; Dear Mr. Short: This responds to your letter to our office concerning our certificatio requirements for manufacturers of school buses. I apologize for the delay in responding to your inquiry.; According to your letter, California's school bus regulations requir vehicles considered as 'school buses' under state law to be certified as 'school buses' under Federal law. Vehicles considered as 'school buses' under state law include multipurpose passenger vehicles (MPV's) used to carry two or more handicapped pupils confined to wheelchairs. Consequently, under California's school bus regulations, an MPV cannot be used to carry handicapped students unless it is certified as meeting our school bus safety standards. Because manufacturers have informed you that NHTSA prohibits them from certifying an MPV as a school bus, you request that we remove this restriction by permitting the school bus certification for MPV's.; Your understanding is correct that our regulations prohibit MPV's to b certified as 'school buses.' Under the National Traffic and Motor Vehicle Safety Act and NHTSA regulations, manufacturers classify their new motor vehicles in accordance with the definitions we issued for our motor vehicle safety standards (49 CFR Part 571.3) and certify that their vehicles meet all Federal safety standards applicable to the vehicle type. Under the definitions of Part 571.3, the issue of seating capacity makes the school bus and MPV definitions mutually exclusive. The passenger seating capacity of an MPV must be 9 or less, while that of a school bus must be 10 or more. A manufacturer cannot certify a vehicle as a 'school bus' in compliance with Federal school bus safety standards unless the vehicle is of a size that puts it within the school bus category.; Adopting your suggestion that we permit some MPV's to be certified a school buses could not be accomplished without changing either our 'school bus' definition, our regulations for certifying vehicles, or the application of our school bus safety standards. As explained below, we must decline your implicit request to make these changes because of a statutory restriction and because we believe their adoption is not warranted by a safety need.; We are precluded from adopting the suggestion that we expand our schoo bus definition to include some MPV's because our school bus definition is governed by legislation enacted by Congress. In the Motor Vehicle and Schoolbus Safety Amendments of 1974, Congress added a 'school bus' definition to the National Traffic and Motor Vehicle Safety Act which is based on the design and intended use of a 'bus.' Congress directed that upgraded school bus safety requirements be applied to buses that carry more than 10 passengers and that are determined by NHTSA likely to be significantly used for the purpose of school transportation.; Your second implicit suggestion is that we change our certificatio regulations to permit manufacturers to certify a vehicle as both an 'MPV' and a 'school bus.' Such a change would not be practical. A manufacturer's certification of a vehicle is a declaration that the vehicle is manufactured to comply with all Federal motor vehicle safety standards applicable to that vehicle type. Since our performance requirements for MPV's are not identical to those for school buses, an MPV cannot be manufactured to meet the standards applicable to both vehicle types.; The third suggestion implicit in your letter is that a dua certification can be effectuated by extending the application of our school bus safety standards to some MPV's. We are not aware of any data suggesting a safety need for such a change. MPV's already have their own safety standards to ensure adequate levels of safety performance for those vehicles. Because of those standards, we do *not* prohibit the sale of MPV's to transport school children. Further, we do not believe the change you suggest is necessary to address the issue raised in your letter. Federal law does not prohibit manufacturers from voluntarily manufacturing MPV's to meet school bus standards on aspects of performance that do not conflict with MPV standards, such as emergency exits and joint strength. California may thus specify performance standards now applicable to school buses for MPV's used to transport handicapped children, provided that the MPV's can continue to comply with MPV standards. Of course, the vehicles would still be certified only as MPV's.; In your letter, you mentioned that you examined the definitions se forth in Highway Safety Program Standard No. 17, *Pupil Transportation Safety*, for 'Type I' and 'Type II' school vehicles. As you know, Standard No. 17 was issued under the Highway Safety Act as a standard for State highway safety programs. Since the 'standard' consists of our recommendations for the operation of school vehicles, the Type I and Type II school vehicle definitions found in Standard No. 17 are relevant for determining the operational recommendations applicable to different school vehicles. Those definitions do not, however, change the Vehicle Safety Act's definition of a school bus or the Act's requirements for a manufacturer to certify school buses to all applicable Federal motor vehicle safety standards.; I hope this information is helpful. Please contact my office if yo have further questions.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3445OpenMr. Antonia Cano, Sales Representative, P.O. Box 904, Buckingham, PA 18912; Mr. Antonia Cano Sales Representative P.O. Box 904 Buckingham PA 18912; Dear Mr. Cano: This responds to your question raised during a meeting with Carl Clark Vernon Bloom, Harry Thompson and Edward Glancy, whether any Federal motor vehicle safety standard precludes the importation or sale of your anti-theft device called 'Hyperblock.' The device works by preventing release of the brakes. Installation of the device requires cutting into a vehicles braking system.; By way of background information, the agency does not give approvals o vehicles or equipment. The National Traffic and Motor Vehicle Safety Act places the responsibility on the manufacturer to ensure that its vehicles or equipment comply with applicable requirements. A manufacturer then certifies that its vehicles or equipment comply with all applicable standards. We note that the term 'manufacturer' is defined by section 102(5) of the Act to mean 'any person engaged in the manufacturing or assembling of motor vehicles or motor vehicle equipment, *including any person importing motor vehicles or motor vehicle equipment for resale*.' Emphasis added. ; The agency does not have any regulations covering anti-theft device that work by preventing release of the brakes.; However, since installation of Hyperblock requires cutting into vehicle's braking system, it may affect a vehicle's compliance with other safety standards.; If your device is added to a new motor vehicle prior to its first sale the person who modifies the vehicle would be an alterer of a previously certified motor vehicle and would be required to certify that, as altered, the vehicle continues to comply with all of the safety standards affected by the alteration. In the case of Hyperblock, this would include Safety Standard No. 105, *Hydraulic Brake Systems* (49 CFR 571.105). You will find the specific certification requirements for alterers at 49 CFR Part 567.7, *Certification*. On the other hand, you as the manufacturer of the device would have no certification requirements, because we have no safety standards applicable to your equipment. However, an alterer would probably require information from you in order to make the necessary certification.; If your device is installed on a used vehicle by a business such as garage, the installer would not be required to attach a certification label. However, it would have to make sure that it did not knowingly render inoperative the compliance of the vehicle with any safety standard. This is required by section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act, which states in relevant part:; >>>No manufacturer, distributor, dealer, or motor vehicle repai business shall knowingly render inoperative, in whole or 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. . .<<<; You indicated at the aforementioned meeting that installation o Hyperblock does not affect a vehicle's braking performance. You also indicated that Hyperblock maintains the integrity of a vehicle's split system. In addition to requirements in those areas, Standard No. 105 establishes brake system integrity requirements, requiring that a braking system be able to withstand a series of spike stops. You may wish to consider testing Hyperblock as to whether it affects a vehicle's compliance with the spike stop test requirements, if you have not done so already. We suggest that you carefully examine all of Standard No. 105's requirements to determine the degree to which installation of your device affects compliance with the standard.; While we do not have any opinion as to the safety of your particula device, we do have a general concern about the safety of anti-theft devices which work by preventing release of the brakes. We note that some manufacturers state in their service manuals that hydraulic brake locking devices should not be used on their vehicles.; Should a safety-related defect be discovered in your device, whether b the agency or yourself, you as the manufacturer would be required under sections (sic) 151 *et seq*. of the Act to notify vehicle owners, purchasers, and dealers and provide a remedy for the defect.; Finally, in addition to the provisions of Federal law discussed above there is a possibility of liability in tort should your device prove to be unsafe in operation. You may wish to consult a local lawyer concerning liability in tort.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3916OpenMr. Kent Cox, Allied Automotive, Bendix Safety Restraints Division, 353 Cass Avenue, Mount Clemens, MI 48043; Mr. Kent Cox Allied Automotive Bendix Safety Restraints Division 353 Cass Avenue Mount Clemens MI 48043; Dear Mr. Cox: This responds to your letter of February 26, 1985, concerning th corrosion resistance requirements of Standard No. 209, *Seat Belt Assemblies* for safety belt attachment hardware. You asked whether the standard uses a 24 hour salt spray test or a 48 hour salt spray test. As explained below, the length of the test depends on what type of safety belt attachment hardware is being tested.; Section S5.2(a) of the standard sets out the test procedures for th corrosion resistance requirements for attachment hardware. The test procedure provides that if the attachment hardware is used at or near the floor of a vehicle, it shall be tested for a 50 hour period, consisting of two 24 hour exposures to salt spray followed by a one hour drying period following each exposure. If the hardware is not used at or near the floor of a vehicle, then it is subjected to a 25 hour test, consisting of one period of 24 hours exposure to salt spray followed by a one hour drying period.; If you have further questions, please let me know. Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam2604OpenMr. Byron A. Crampton, Manager of Engineering Services, Truck Body and equipment Association, Inc., 5530 Wisconsin Avenue, N.W., Washington, D.C. 20015; Mr. Byron A. Crampton Manager of Engineering Services Truck Body and equipment Association Inc. 5530 Wisconsin Avenue N.W. Washington D.C. 20015; Dear Mr. Crampton: This responds to your April 6, 1977, letter asking whether two propose labels satisfy the requirements for certification and information labels found in 49 CFR Part 567, *Certification*, and Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*.; The National Highway Traffic Safety Administration (NHTSA) does no issue advance approval of compliance by manufacturers with motor vehicles safety standards or regulations. The agency, however, will give an informal opinion as to whether your sample labels appear to comply with NHTSA regulations. From the illustrations you present, it appears that you have closely followed the format suggested in our regulations, and therefore, the labels seem to comply with the agency's requirements. Section S5.3(b) of Standard No. 120 permits the use of both labels when affixed in accordance with Part 567.4(b)-(f).; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0639OpenMr. Franklin E. de Luna, The Daystar Motor Homes, Inc., P.O. Box 20325, Los Angeles, CA 90006; Mr. Franklin E. de Luna The Daystar Motor Homes Inc. P.O. Box 20325 Los Angeles CA 90006; Dear Mr. de Luna: This is in reply to your letter of February 4 asking for copies o regulations applicable to a 'motor home' you wish to manufacture.; I enclose a copy of the National Traffic and Motor Vehicle Safety Ac of 1966, the basic statute setting forth your obligations as a manufacturer, and the authority for all applicable regulations. A publication titled 'Federal Motor Vehicle Safety Standard and Other Regulations' is available from the Superintendent of Documents, Government Printing Office, Washington, DC 20402. The price of $8.00 includes a subscription of up to one year of supplements. The Federal standards and regulations also appear in Title 49 of the Code of Federal Regulations (Title 19 for the importation regulations), generally available at law libraries. Amendments and proposals are published, when issued, in the *Federal Register*.; If you have any questions after obtaining and receiving these material I will be happy to answer them for you. A 'motor home' for your information, is defined as a 'multipurpose passenger vehicle' under the Federal standards.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1881OpenMr. H. P. Montgomery, Jr., Montgomery GMC Trucks, Inc., 836 North Glenstone, Springfield, MO 65801; Mr. H. P. Montgomery Jr. Montgomery GMC Trucks Inc. 836 North Glenstone Springfield MO 65801; Dear Mr. Montgomery: This responds to your March 26, 1975, request for guidance i establishing basis for certification to Standard No. 121, *Air brake systems*, in the case of a truck to which you add a third axle.; While your letter lists five bases which might be used i certification, it is not necessary to employ all of these approaches. Rather the National Traffic and Motor Vehicle Safety Act requires that you exercise 'due care' to assure that your products conform to the standard (15 U.S.C. 1397(B)(1)). What constitutes 'due care' in a particular case depends on all relevant facts, including such things as the time to elapse before a new effective date, the availability of test equipment, the limitations of current technology, and above all the diligence evidenced by the manufacturer.; As a general response to your questions, if testing facilities are no available to an intermediate or final-stage manufacturer, or the cost of his testing a vehicle directly to the requirements of Standard No. 121 is prohibitive, such a company should develop an alternative method of determining that his alternations (sic) do not take a vehicle out of compliance with the standard. These methods could include testing of typical installations by independent contractors working with associations of companies such as TBEA or TEBDA, testing of typical installations by suppliers of the axles or other components sought to be installed, engineering calculations by the alterer, the alterer's supplier, or by independent contractors, or copying of installations that have been approved by chassis manufacturers. Component (e.g., axle) suppliers would appear to be a prime source of the type of assistance needed by intermediate and final-stage manufacturers, since they are most familiar with the main components of the installation and have the greatest economic interest in seeing this segment of the industry maintained.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0793OpenMr. Charles R. Matthews, Senior Safety Engineer, Oshkosh Truck Corporation, P. O. Box 560, Oshkosh, WI 54901; Mr. Charles R. Matthews Senior Safety Engineer Oshkosh Truck Corporation P. O. Box 560 Oshkosh WI 54901; Dear Mr. Matthews: This is in response to your letter of June 30, 1972, requestin information on a proper course of action to take concerning your placement of incorrect information on certification labels.; The placement of incorrect information of the type you describe (a overstatement of gross axle weight rating) may be a 'safety related defect' under the National Traffic and Motor Vehicle Safety Act. This would be the case if loading the vehicle to the specified rating would result in an unsafe operating condition.; Whether a defect exists is to be determined in the first instance b the vehicle manufacturer. If you determine that a defect exists, section 113 of the Act (15 U.S.C. 1402) requires that you notify first purchasers by certified mail, describing the defect, its effect on safety, and measures to be taken to correct it. The determination that a defect exists can also be made independently by NHTSA, which would then order the manufacturer to send the required notification. Regulations issued by NHTSA (Defect Reports, 49 CFR Part 573) require manufacturers of vehicles having safety defects to submit certain information to NHTSA, and to compile a list of affected owners.; Replacing the improper labels, as you have suggested, would be a appropriate action to take to rectify this situation and satisfy the Certification regulations.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2254OpenMr. Raymond Oleisky, Operations Manager, Trans-continental Tire Sales, Inc., 9 Fourth Street, S.W., Osseo, Minnesota 55369; Mr. Raymond Oleisky Operations Manager Trans-continental Tire Sales Inc. 9 Fourth Street S.W. Osseo Minnesota 55369; Dear Mr. Oleisky: I am writing to confirm your March 19, 1976, telephone conversatio with Mark Schwimmer of this office concerning Federal Motor Vehicle Safety Standard No. 119, *New Pneumatic Tires for Vehicles Other than Passenger Cars*.; Standard No. 119 requires that the symbol 'DOT' appear on the sidewal of a non-passenger car tire, as a certification that the tire meets all of the standard's performance and labeling requirements. Assuming that the tire in question does meet those requirements and is so certified, there is no prohibition in the standard against additional labeling such as 'Blem' or 'A.B.O.' I hope this clarifies the status of your tires.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0269OpenJames A. Morgan, Esq., Assistant Counsel, B.F. Goodrich Company, 500 South Main Street, Akron, OH 44318; James A. Morgan Esq. Assistant Counsel B.F. Goodrich Company 500 South Main Street Akron OH 44318; Dear Mr. Morgan: This is in reply to your letter of November 20, 1970 concerning you telephone conversation with Mr. Schmeltzer of my office, relating to the Tire Identification and Record Keeping Regulations (Docket No. 70-12, Notice No. 2).; You are not completely correct in your understanding that, as a resul of the tire identification regulations, the DOT symbol will only be required on the sidewall of the tire where the identification number will appear. As indicated in the preamble of the notice of proposed rulemaking on these regulations, it is anticipated that the identification number required by the regulation will replace the manufacturer's identification number required by Standard No. 109. However, no decision has been made as yet whether Standard No. 109 will also be amended to require the 'DOT' symbol on only one sidewall of the tire.; You are correct in your understanding that the regulations were no intended to restrict the third grouping of characters, the optional tire type code, to three symbols (sic) In addition, you are correct in your understanding that a tire manufacturer will receive individual identification numbers for each of its tire manufacturing and retread plants.; Under the regulations, B.F. Goodrich will not be required to apply fo identification marks for Goodrich owned brand name tires if sold and controlled by them.; Concerning your question as to what class of certified mail would b required in the event of a recall, a notification letter sent by certified mail to the addressee, himself, would be preferable but is not, at this time, required by the Act or any regulation issued thereunder.; Thank you for your interest. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam5591OpenHelen A. Rychlewski MGA Research Corporation 900 Mandoline Street Madison Heights, MI 48071; Helen A. Rychlewski MGA Research Corporation 900 Mandoline Street Madison Heights MI 48071; "Dear Ms. Rychlewski: This responds to your letter of June 7, 1995, t the National Highway Traffic Safety Administration (NHTSA), requesting an interpretation of whether a vehicle can be certified as meeting the seat back requirements in S3.2 of Federal Motor Vehicle Safety Standard (FMVSS) No. 201, Occupant Protection in Interior Impact, based on the results of a particular test. The vehicle is equipped with a seat with an inertial latch on the recliner. In order to keep the seat from folding forward during the test procedure specified in FMVSS No. 201, you welded the inertial latch to conduct the test. In past agency interpretation of the safety standards, NHTSA has stated that if (1) there are two or more possible conditions under which a compliance test may be conducted (e.g., whether an inertial lock is engaged or not), (2) the standard does not specify which test condition is to be used, and (3) the language of the standard as a whole and the standard's purpose do not imply a limit that would make one of those conditions inappropriate, there is a presumption that the requirements have to be met under all test conditions. The intent of FMVSS No. 201 is to minimize injuries caused by an occupant striking interior components during a crash. Because inertial latches are intended to lock during a crash, NHTSA believes that testing with the inertial latch engaged most closely indicates the protection offered to an occupant during a crash. Therefore, NHTSA would test a vehicle seat back on a seat with an inertial latch with the latch engaged. The test procedures in NHTSA standards are the procedures NHTSA will use in compliance testing. While manufacturers are not required to test their products using those procedures, they must ensure that the vehicle would comply when tested by NHTSA. NHTSA could weld the latch as you have done, or could engagethe inertial latch through other means. If you believe that the test you conducted indicates that the seat back will comply when tested by NHTSA with the latch engaged, such a test may be the basis for your certification. I hope this information has been helpful. If you have any other questions or need additional information, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack 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.