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: aiam3131OpenMr. Roger E. Maugh, Director, Automotive Safety Office, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. Roger E. Maugh Director Automotive Safety Office Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Maugh: Re: Distribution of Imported Vehicles Brought Into Conformity Wit Applicable Federal Motor Vehicle Safety Standards; This is in reply to Mr. Eckhold's letter of September 28, 1979, to Mr Vinson of this office asking for our concurrence in Ford's wish to sell 60 1978 model Ford Fiestas on the American market.; According to Mr. Eckhold's letter, 56 of the cars did not comply wit the Federal motor vehicle safety standards at the time they entered the United States for use by Ford in testing and training programs. Ford represents that all these have now been brought into compliance. The four remaining Fiestas conformed at the time of entry but, presumably, because of the execution of the HS-7 importation form, were not certified.; We concur with Ford's opinion that all conforming vehicles may now b sold in the United States. However, since such sales are to first purchasers for purposes other than resale, a certification label must be attached to each that meets the requirements of 49 CFR Part 567.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3561OpenMr. J. F. Walkup, Project Analyst, Research & Development Center, Reeves Brothers, Inc., Post Office Box 26596, Charlotte, NC 28213; Mr. J. F. Walkup Project Analyst Research & Development Center Reeves Brothers Inc. Post Office Box 26596 Charlotte NC 28213; Dear Mr. Walkup: This responds to your April 6, 1982, letter asking whether the agency' standard No. 302, *Flammability of Interior Materials*, applies to after-market equipment. The answer to your question is no.; Standard No. 302 is a vehicle standard and as such applies to complete vehicles. No vehicle can be manufactured unless the materials used in it comply with the requirements of the standard. The standard does not apply, however, to items of equipment in the after market. You should be aware that while you would not be prohibited from manufacturing after-market equipment that does not comply with the standard, a manufacturer, repair business or dealer would be prohibited from installing such noncomplying equipment if the installation would have the effect of rendering inoperative the compliance of the vehicle with the safety standard. Nothing prevents a vehicle owner, however, from installing noncomplying equipment in his own vehicle.; I trust that this responds to your question. Please contact me if I ca be of further assistance.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4070OpenMr. Robert J. Crail, Theurer, Inc., Route 1, Box 300, Helenwood, TN 37755; Mr. Robert J. Crail Theurer Inc. Route 1 Box 300 Helenwood TN 37755; Dear Mr. Crail: This responds to your letter of August 20, 1985, requesting a interpretation of Standard No. 121, *Air Brake Systems* (49 CFR 571.121). You asked whether an extendable intermodal container chassis which adjusts to haul containers which vary in length between 40 feet and 48 feet is a 'heavy hauler trailer' as defined in Section S4 of Standard No. 121. Specifically, you would like to know whether the extendable container chassis described above must comply with Sections S5.2.1.2 and S5.3, and whether you or your customer may utilize the options available in Section S5.6 for parking brake systems and in Section S5.8 for emergency brake systems.; By way of background information, this agency does not give approval of motor 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 and equipment comply with all applicable standards. The following represents our opinion based on the facts provided in your letter.; The extendable container chassis trailers which you describe have brak lines which are designed to extend with the vehicle frame. According to Section S4 of Standard No. 121, a trailer whose 'brake lines are designed to adapt to separation or extension of the vehicle frame....' is, by definition, a heavy hauler trailer. Thus, your extendable chassis trailer would be considered a heavy hauler trailer within the definition of S4.; Section S5.2.1.2 of Standard No. 121 provides that trailers with ai brakes are generally required to have total service reservoir volume which is 'at least eight times the combined volume of all service brake chambers at maximum travel of the pistons or diaphragms.' This general rule is limited by the last sentence of S5.2.1.2 which provides, 'However, the reservoir on a heavy hauler trailer ... need not meet this requirement.'; Section S5.3 sets forth road test requirements, compliance with whic must be certified for all trucks, buses and trailer. Generally, all trailers are required to be certified as complying with the timing requirements of S5.3.3 and S5.3.4. This general rule is limited by the last sentence of S5.3, which specifies, 'However, a heavy hauler trailer ... need not meet the requirements of S5.3.' Thus, heavy hauler trailers are expressly excepted from all of the requirements of S5.3.; Finally, you asked whether the trailer you manufacture may tak advantage of the options available in Section S5.6 for the parking brake system and in Section S5.8 for the emergency brake system. Both Sections S5.6 and S5.8 specifically give manufacturers of heavy hauler trailers the choice of complying with the requirements of those sections... 'or at the option of the manufacturer, the requirements of sec. 393.43 of this title.' Title 49 CFR section 393.43 sets forth requirements for breakaway and emergency brakes. An extendable container chassis which comes within the S4 definition of heavy hauler trailer may comply with the section 393.43 requirements or the parking and emergency brake requirements of Standard No. 121 Sections S5.6 and S5.8, respectively.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1788OpenMr. J.W. Kennebeck,Volkswagen of America, Inc.,Englewood Cliffs, New Jersey 07632; Mr. J.W. Kennebeck Volkswagen of America Inc. Englewood Cliffs New Jersey 07632; Dear Mr. Kennebeck:#This responds to Volkswagen of America's Januar 24, 1975, request for written confirmation that S5.3.3 of Standard No. 105-75, *Hydraulic brake systems*, only requires indication of a low fluid level condition (S5.3.1(b)) with the vehicle on a level surface, but that, in the event of a decrease in this fluid level (and apparent fluid volume) due to positioning the vehicle on an incline, the indicator lamp is permitted to activate and then deactivate when the vehicle is repositioned on a level surface.#Your understanding of the requirements of S5.3.3. for indication of a low fluid level condition (S5.3.1(b)) is correct. S5.3.3 requires low fluid level indication with the vehicle on a level surface, and an activation due only to positioning on an incline may be extinguished when the vehicle is again placed an a level surface.#Yours truly,Richard B. Dyson,Assistant Chief Counsel; |
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ID: aiam1272OpenHonorable Quentin N. Burdick, United States Senate, Washington, DC 20510; Honorable Quentin N. Burdick United States Senate Washington DC 20510; Dear Senator Burdick: This is in further reply to your letter of September 7, 1973 concerning correspondence you received from Mr. Alton R. Rau of Linton, North Dakota. Mr. Rau objects to Federal regulations which require him to purchase trucks with stronger axles and tires than those trucks which he formerly purchased.; The National Highway Traffic Safety Administration Certificatio regulations (49 CFR Parts 567 and 568) require manufacturers to establish gross vehicle and gross axle weight ratings, and to equip new vehicles with components, including tires and axles, that are of sufficient capacity to carry intended loads. The regulations do not establish the relevant ratings, which are established solely by manufacturers. We feel the justification in terms of safety for such requirements is obvious.; We believe situations such as that experienced by Mr. Rau where according to manufacturer's figures, vehicles should have been equipped with stronger axles and tires, demonstrate the need for the Certification requirements rather than showing them to be unnecessary.; The regulations apply only to new motor vehicles, and not to vehicle already in use. For Mr. Rau's information I have enclosed a copy of these requirements.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam4420OpenMr. Robert C. Geschwender, Lin-Mart, P.O. Box 82431, Lincoln, NE 68501-2431; Mr. Robert C. Geschwender Lin-Mart P.O. Box 82431 Lincoln NE 68501-2431; Dear Mr. Geschwender: This responds to your November 1, 1978 letter to me asking whether an of our regulations apply to the 'Head Hugger,' an aftermarket product you have designed for use in motor vehicles. The Head Hugger is a head pillow that attaches to a head restraint and is designed to support a passenger's head and neck when he or she is seated in a reclined position. I hope the following information is helpful.; The National Highway Traffic Safety Administration (NHTSA) has th authority to regulate the manufacture and sale of new motor vehicles and items of motor vehicle equipment. Although NHTSA has issued motor vehicle safety standards for certain types of motor vehicle equipment, we have no standard directly applicable to the Head Hugger. Thus, the manufacture and sale of your aftermarket product to a vehicle owner for installation in his or her vehicle would not be affected by the requirements of any Federal motor vehicle safety standard.; However, if the Head Hugger will be installed in new or used vehicle by a commercial business, then S108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act could affect your product in certain circumstances. 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 safety standard. These commercial entities could sell your product, but could not install it if the installation would negatively affect the vehicle's compliance with our standards for occupant protection in interior impacts (Standard No. 201), head restraints (Standard No. 202) or flammability resistance (Standard No. 302). In the first instance, it would be the responsibility of these entities to determine whether there is any possibility of such an effect.; Again, however, the prohibitions of S108(a)(2)(A) do not apply to th 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 Head Hugger, even if doing so would negatively affect some safety feature in his or her vehicle.; There is an additional aspect of the Act of which you should be aware The Act requires the recall and remedy of motor vehicles and motor vehicle equipment determined to contain a defect relating to motor vehicle safety. If you or NHTSA determine that the Head Hugger contains such a defect, you must recall and repair or replace the item without charge to the purchaser.; We have enclosed a copy of the Act, and an information sheet describin how you can obtain copies of our motor vehicle safety standards and any other NHTSA regulation. Please contact us if we can be of further assistance.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam0930OpenJerome Palisi, Highway Safety Management Specialist, Region II; Jerome Palisi Highway Safety Management Specialist Region II; Subject: Your memorandum of November 9, 1972, regarding th Certification regulation.; In your memorandum of November 9 you discuss a statement in a TBE Bulletin, brought to your attention by Mr. Edward Bristol of the Bristol=Donald Company, Newark, New Jersey, which Mr. Bristol interprets as holding a manufacturer responsible for a safety defect if an operator overloads a vehicle, exceeding its GVWR and GAWR's. You ask us to forward you copies of any correspondence with Mr. Bristol or TBEA regarding this matter.; We have attached a recent letter to TBEA, dated November 22, 1972 which clarifies our position, and should alleviate Mr. Bristol's concern. Our position on this issue has been that a manufacturer who properly derives his GVWR and GAWR cannot be held responsible for noncompliance with the certification regulations or a safety defect.; From: Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1622OpenMr. Burt Weller, Engineering Manager, Truck Trailer Manufacturers Assoc., 2430 Pennsylvania Avenue, N.W., Washington, DC 20037; Mr. Burt Weller Engineering Manager Truck Trailer Manufacturers Assoc. 2430 Pennsylvania Avenue N.W. Washington DC 20037; Dear Mr. Weller: This is in reply to your letter of September 4, 1974, in which you as several questions regarding the possible manufacture of semitrailers designed to transport people. You state the semitrailers would be pulled by conventional tractors, would have air-operated bus-type side doors, a rear door for emergency exit, seats, handrails for passengers who stand, and windows that open and close. Communication between the passenger compartment and driver would be limited to a horn that the driver can blow and a blinking red light operable by either a passenger or the driver. You ask whether this type of vehicle is legal, whether it is legal to transport passengers in this fashion, and what specific requirements would be required to be built into the trailer.; We would consider the vehicles in question to be trailers under th Motor Vehicle Safety Standards, and consequently subject to the standards applicable to trailers. These standards are Standard No. 108, 'Lamps, reflective devices, and associated equipment,' Standard No. 106, 'Brake hoses' (eff. as to trailers on September 1, 1975), and Standard No. 121, 'Air brake systems' (eff. as to trailers on January 1, 1975), at this time. The trailers would, of course, have to be certified as conforming to all applicable standards, in accordance with the Certification Regulations (49 CFR Parts 567, 568).; Many States prohibit the transportation of passengers in trailers, an as a consequence NHTSA requirements for crashworthiness and occupant protection have not been made applicable to trailers. These requirements include those for restraint and seating systems, glazing materials, head restraints, and emergency exits. Whether or not State laws prohibiting the transportation of passengers in trailers would apply to semitrailers of this type would depend upon each State's interpretation of its law, and that information should be obtained from the various states. However, should it become a commonly permitted practice for persons to be transported in trailers, this agency would very likely expand its occupant protection and crashworthiness requirements through rulemaking to apply to these vehicles.; The transportation in interstate commerce of passengers for hire als falls within the regulatory authority of the Bureau of Motor Carrier Safety, in the Federal Highway Administration. We have forwarded your letter to that agency, requesting that it respond directly to you regarding the effect of regulations it administers on vehicles of this type.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam4973OpenMr. Carl J. Clement Clement Associates 12785 Dianne Drive Los Altos Hills, CA 94022; Mr. Carl J. Clement Clement Associates 12785 Dianne Drive Los Altos Hills CA 94022; "Dear Mr. Clement: This responds to your letter of January 28, 199 requesting information on any Federal regulations that may affect a new product you are developing. The product is an electronically-operated automotive sun visor that would automatically detect the direction of sunlight or glare and reposition itself to shield the driver. I am pleased to have this opportunity to explain our regulations to you. By way of background information, 103 of the National Traffic and Motor Vehicle Safety Act (Safety Act, 15 U.S.C. 1392) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue safety standards for new motor vehicles and new items of motor vehicle equipment. NHTSA does not, however, approve or certify any vehicles or items of equipment. Instead, the Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. The agency periodically tests vehicles and items of equipment for compliance with the standards. In addition, the Safety Act requires manufacturers to recall and remedy any motor vehicle or item of motor vehicle equipment that contains a safety-related defect. NHTSA has issued two safety standards that apply to sun visors: Standard No. 201, Occupant protection in interior impact, and Standard No. 302, Flammability of interior materials. These standards are called vehicle standards, because they apply to new vehicles, not to individual pieces of equipment. The Safety Act specifies that vehicles must conform with all applicable safety standards up until the first purchase for purposes other than resale. Therefore, if your sun visor were installed as original equipment by a manufacturer of a new motor vehicle, the visor would have to comply with the requirements of these two standards. Standard No. 201 requires that the visor be 'constructed of or covered with energy-absorbing material' and that the visor's mounting must 'present no material edge radius of less than 0.125 inch that is statically contactable by a spherical 6.5-inch diameter head form.' The purpose of that requirement is to reduce the injuries that occur when unrestrained occupants strike the visor or its mounting with their heads. Standard No. 302 requires sun visors to meet the flammability resistance requirements of the standard. The standard specifies that the material used on the visor must not burn at a rate of more than four inches per minute. If a new vehicle is altered by the installation of your product prior to the vehicle's first sale to a consumer, the person making the installation is considered an 'alterer' and is required by 49 CFR Part 567, Certification, to certify that the vehicle complies with all applicable safety standards affected by the alteration. In addition to Standards No. 201 and 302, the installation of your product might affect the compliance of a vehicle with a number of other safety standards, including Standard No. 111, Rearview mirrors, and Standard No. 208, Occupant crash protection. After the first sale to a consumer, a vehicle is no longer required by Federal law to conform to all safety standards. However, 108(a)(2)(A) of the Safety Act provides as follows: No manufacturer, distributor, dealer, or motor vehicle repair 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... In order to avoid violating this provision, a manufacturer, dealer, distributor, or repair business which installed your sun visor would have to ensure that such installation enables the vehicle to continue to comply with all applicable safety standards. Violations of 108(a)(2)(A) are punishable by civil fines of up to $1,000 per violation. I note that 108(a)(2)(A) does not affect modifications made by vehicle owners to their own vehicles. Finally, under the Safety Act, your sun visor would be considered an item of motor vehicle equipment. If your sun visor will be sold as an item of equipment to be installed by the vehicle owner, there is currently no Federal motor vehicle safety standard that applies. However, even if there is no safety standard applicable to the item of motor vehicle equipment, the manufacturer is subject to the requirements in 151-159 of the Safety Act concerning the recall and remedy of products with safety defects. In the event that NHTSA or a manufacturer determines that a manufacturer's product contains a safety-related defect, the manufacturer is responsible for notifying purchasers of the defective equipment and remedying the problem free of charge. Additionally, a company making your product would be considered a manufacturer. A manufacturer is required by 49 CFR Part 566, Manufacturer Identification, to submit information identifying itself and its products to NHTSA not later than 30 days after it begins manufacture. I have enclosed an information sheet for new manufacturers which summarizes NHTSA's regulations and explains where to obtain copies of Federal motor vehicle safety standards. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam0199OpenMr. Bernard Belier, U. S. Resident Engineer, U. S. Technical Research Corporation, 801 Second Avenue, New York, NY 10017; Mr. Bernard Belier U. S. Resident Engineer U. S. Technical Research Corporation 801 Second Avenue New York NY 10017; Dear Mr. Belier: This is in reply to your letter, dated November 11, 1969, in which yo seek an interpretation as to how Federal Motor Vehicle Safety Standards (FMVSSs) 103 and 104 are applicable to cars equipped with right-hand drive or a central steering wheel.; For motor vehicles equipped with right-hand drive, the windshield area to be defrosted and wiped by FMVSSs 103 and 104 respectively, are mirror images of those areas required for vehicles equipped with left-hand drive.; More information is required before a reply can be given on vehicle equipped with a central steering wheel. Defrosting and wiping areas requirements would naturally vary depending on the number and location of the front seat passenger seating positions in the vehicle equipped with a central steering wheel.; We trust that we have been of assistance to you. Sincerely, Robert Brenner,Acting Director |
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.