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: aiam4544OpenMr. Byung M. Soh Marketing Director Target Marketing Systems, Inc. P.O. Box 59483 Chicago, IL 60659-0483; Mr. Byung M. Soh Marketing Director Target Marketing Systems Inc. P.O. Box 59483 Chicago IL 60659-0483; Dear Mr. Soh: This is in reply to your letter of June 20, 1988, wit respect to two motor vehicle lighting products which you intend to import into the United States. You have asked 'whether these devices require approvals from D.O.T.' First let me explain that the Department of Transportation does not 'approve' or 'disapprove' specific products. It does advise whether a product appears allowable under the National Traffic and Motor Vehicle Safety Act and the Federal Motor Vehicle Safety Standards. Your letter does not indicate whether you wish to market these devices as original equipment to be installed before initial sale of a motor vehicle, by either its manufacturer or dealer, or whether you intend to market them solely through the aftermarket. I shall address each situation. The Federal motor vehicle safety standard that applies to original equipment is Standard No. 108 Lamps, Reflective Devices and Associated Equipment. Paragraph S4.1.3 of Standard No. 108 allows additional motor vehicle equipment provided that it does not impair the effectiveness of the lamps and reflectors required as original equipment. Effectiveness may be impaired if the device creates a noncompliance in the existing lighting equipment or confusion with the signal sent by another lamp, or functionally interferes with it, or modifies its candlepower to either below the minima or above the maxima permitted by the standard. In addition, a motor vehicle must remain in conformance with Standard No. 108 (and all other safety standards) until its first purchase for purposes other than resale. There is no Federal standard that applies to your devices as aftermarket equipment, but the National Traffic and Motor Vehicle Safety Act prohibits a manufacturer, distributor, dealer, or motor vehicle repair business from knowingly rendering inoperative, in whole or in part, original lighting equipment. Your first device is called a 'foglight converter.' The advertising literature attached states that its function is to turn 'the existing headlights...into foglights....' In our opinion, such a device would create a noncompliance with Standard No. 108 by rendering the headlamp function unavailable when the fog lamp converter is in use. We shall assume that the headlamp would be converted into a fog lamp meeting the specifications of SAE Standard J583 May81 Front Fog Lamps. None of the photometric test points of SAE J583 coincide with those specified for headlamps. Our further concern with this device is that a driver might fail to return to the headlamp mode from the fog lamp mode, and operate the vehicle with reduced frontal lighting. The situation differs with respect to the aftermarket. Under the National Traffic and Motor Vehicle Safety Act, a manufacturer, distributor, dealer, or motor vehicle repair business may not perform modifications that render inoperative, in whole or in part, equipment such as headlamps added pursuant to a Federal safety standard. We believe that the installation of the converter could affect the operability of the headlamp within the meaning of the statutory prohibition. However, we note that the foglight converter is advertised as 'easy for any driver to attach to any vehicle.' As an owner is not a manufacturer, distributor, dealer, or motor vehicle repair business, the owner is not restricted under Federal law from modifications to his vehicle. He is, however, subject to the laws of the States in which his vehicle is registered and operated. We are not conversant with how State lighting laws might affect use of the foglight converter, and you may wish to obtain an opinion from the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, VA 22203. We have several other comments as well. The literature you enclosed depicts the foglight converter attached to what appears to be the European-designed H-4 bulb. Standard No. 108 does not permit headlamps with H-4 light sources to be sold for use on 4-wheeled motor vehicles. In addition, the application of the device where motion is translated from the lamp's exterior to the interior by a linkage in the bulb base would affect compliance with the requirement that the bulb base withstand a pressure differential of l0 psi. Additionally, creating a hole or passage for a linkage has the potential of rendering the headlamp noncompliant with Standard No. 108's requirements for certain environmental tests, such as resistance to dust, corrosion, and humidity. Your second device is a 'headlamp intensity modulator,' adjusting a headlamp beam 'automatically from low to high beam through a middle beam.' According to your literature, when a sensor notes the beams of an oncoming car 500 meters ahead the upper beam gradually passes through a middle beam and diminishes into a lower beam when the vehicles are 150 meters apart. This device is also advertised as capable of owner installation, and without the modification of any vehicle parts. The system appears to operate by a switch. This device directly conflicts with Standard No. 108, and its use would create a noncompliance with it. Headlamps are defined as producing upper and lower beams, and means must be provided for switching between these beams. Use of the device would alter upper and lower beam characteristics from those required by Standard No. 108, and in effect create an infinite number of beams while passing from a conforming upper beam at one extreme to a conforming lower beam at the other. This precludes its use as original equipment. We believe that its aftermarket legality would be limited. Although Federal law would not preclude an owner from installing it, the instructions are sufficiently complex that in our opinion many purchasers would seek help from a 'dealer' or 'motor vehicle repair business,' which could not be legally given. There would also remain the question of legality with State laws. These appear to be innovative devices and we regret that we cannot be more encouraging. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam2886OpenMr. William M. Nettles, Rome Engineering & Manufacturing Co., P.O. Box 707, Claxton, GA 30417; Mr. William M. Nettles Rome Engineering & Manufacturing Co. P.O. Box 707 Claxton GA 30417; Dear Mr. Nettles: This responds to REMCO's September 14, 1978, request to know th Federal braking requirements for an air-braked or pulpwood trailer.; In addition to the requirements of Standard No. 106-74, *Brake Hoses* the only Federal Motor Vehicle Safety Standard regulating the braking of air-braked vehicles is Standard No. 121, *Air Brake Systems*. As you know, Federal Motor Carrier Safety Standards also apply to the use of air-braked vehicles in interstate commerce.; All of the requirements of Standard No. 121 apply to the manufacture o a logging or pulpwood trailer except for the 'no lockup' provision of S5.3.2. Specifically, S5.3.2.2 of the standard states:; >>>S5.3.2.2 When stopped in accordance with S5.3.2, any traile designed exclusively for harvesting logs or pulpwood and constructed with a skeletal frame and no means for attachment of a solid bed, body, or container, and with an arrangement of air control lines and reservoirs designed to minimize damage in off- road operations, need not meet the requirements relating to wheel lockup, but must nevertheless meet the requirements of staying within the 12-foot lane.<<<; There is no exclusion from the parking brake requirements of S5.6 Therefore, a parking brake capability using an energy source unaffected by loss of service brake air pressure is required. The standard specifies performance, not design, and does not require installation of a spring brake design. I have enclosed a copy of a recent proposal that would modify the requirements so that pulpwood trailers would not be required to provide parking brake capability. The reasons for this proposal are listed in the preamble to the notice. This proposal has not been made final.; For clarification, I would add that 'heavy hauler' trailers ar excluded from the entire standard until January 1, 1979. Heavy hauler trailers are defined to include the so-called 'pole trailers' used in logging that have air brake lines that adapt to fore-and-aft extension of the trailer.; I am also enclosing a *Federal Register* notice that explains th effect of a recent court decision on the 'no lockup' requirement for trailers.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4051OpenThe Honorable Lloyd Bentsen, United States Senate, 1100 Commerce, Room 7C14, Dallas, TX 75242; The Honorable Lloyd Bentsen United States Senate 1100 Commerce Room 7C14 Dallas TX 75242; Dear Senator Bentsen: Thank you for your recent letters to Administrator Steed on behalf o your constituent, Mr. Joe M. Rutland. I apologize for the delay in our response. Mr. Rutland asked why this agency requires safety warnings to be lithographically marked on brake fluid containers. He believes that this requirement causes undue hardship on small businesses that package brake fluid. I appreciate this opportunity to respond to Mr. Rutland's concerns and to clarify our requirements for brake fluid container labeling.; Some background information on NHTSA's authority to regulate in thi area might be helpful. The National Traffic and Motor Vehicle Safety Act of 1966 (the 'Vehicle Safety Act') authorizes us to promulgate motor vehicle safety standards for new motor vehicles and items of motor vehicle equipment, including brake fluid. Federal Motor Vehicle Safety Standard No. 116, *Motor Vehicle Brake Fluid* (49 CFR 571.116), has been in effect as a motor vehicle safety standard since the passage of the Vehicle Safety Act. In 1971, Standard No. 116 was amended to establish requirements for the labeling of brake fluid containers. The rule required certain safety information to be clearly and indelibly marked on each brake fluid container.; Brake fluid containers must be labeled with specific safety warnings in addition to other general information. The warnings serve as a safeguard against failures in hydraulic braking systems that might result from the use of improper or contaminated fluids. The warnings also help to prevent improper storage of the brake fluid which could contaminate the fluid or cause it to absorb moisture. Avoiding the absorption of moisture is extremely important since moisture in a brake system degrades braking performance and safety by lowering the brake fluid's boiling point, and increases possibilities of vapor lock and brake system component corrosion.; Thus, packagers of brake fluid have been required since 1971 to furnis the safety information clearly and indelibly on each brake fluid container. In response to a request for an interpretation of Standard No. 116 in 1984, NHTSA ruled that the use of labels affixed to brake fluid containers would not comply with the labeling requirements of the standard. However, Standard No. 116 does not mandate that lithography be used to mark the containers, as Mr. Rutland seems to believe. Any technology, whether lithography or otherwise, may be used if the resultant marking on a brake fluid container is clear and indelible and directly on the container itself.; The agency has recently been made aware of the concern that the 198 interpretation of Standard No. 116's labeling requirements may be causing undue hardship for packagers of brake fluid. In response to those concerns, we have been examining Standard No. 116 to assess its current labeling requirements.; I hope this information is helpful. Please contact my office if we ca be of further assistance.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3794OpenMr. Frank Pepe, Assistant Vice President, Engineering Services Division, United States Testing Company, Inc., 1415 Park Avenue, Hoboken, NJ 07030; Mr. Frank Pepe Assistant Vice President Engineering Services Division United States Testing Company Inc. 1415 Park Avenue Hoboken NJ 07030; Dear Mr. Pepe: This responds to your letter concerning Safety Standard No. 209, *Sea Belt Assemblies*. You asked several questions about the requirements applicable to a Type 2 Vehicle Sensitive Emergency Locking Retractor utilizing a tension reducer device. The particular device you are concerned about is, according to your letter, activated by the vehicle door. With the door open the mechanism operates in a high tension mode, with the door closed the mechanism is in a low tension mode.; By way of background information, this agency does not grant approval of vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act it is the responsibility of the manufacturer to certify that its vehicles or equipment comply with applicable requirements. The following represents our opinion based on the facts provided in your letter.; Safety Standard No. 209 specifies requirements concerning minimum an maximum retraction force. Requirements are specified for both initial retraction force and retraction force after a test sequence which includes lengthy retractor cycling. See sections S4.3(j), (k) and S5.2(k).; As you know, retractors have traditionally had only one rather than tw tension modes. Standard No. 209 does not prohibit a design with two tension modes. However, as written, the standard's requirements do not distinguish between tension modes.; We agree with your suggestion that both tension modes should be teste for retraction force effort as specified in the standard. However, we do not agree with your suggestion that the high tension mode should only be tested for minimum retraction force and low tension mode for maximum retraction force. Instead, because Standard No. 209 does not distinguish between tension modes, we interpret the standard to require that all of its requirements must be met in both tension modes. For example, under section S4.3(j)(6), both tension modes must exert a retractive force within the 0.2 to 1.5 pound range. For testing purposes, of course, a single retractor could only be fully tested for one of the two modes, since testing for both modes would involve twice the amount of cycling required by the standard.; Your letter states that since the high tension mode is used only fo stowing the webbing and not in operation during normal use, you believe that only cycling tests without lock-ups should be performed in testing. While we appreciate this argument, the standard, as written, does not permit that exception. Section S5.2(k) states in relevant part:; >>>...An emergency-locking retractor or a nonlocking retractor attache to upper torso restraint shall be subjected to 45,000 additional cycles of webbing withdrawal and retraction between 50 and 100 percent extension. The locking mechanism of an emergency locking retractor shall be actuated at least 10,000 times within 50 to 100 percent extension of webbing during the 50,000 cycles....<<<; Since the standard does not distinguish between tension modes, lock-up should be performed in testing for both the low and high tension modes.; As already noted, the retractor in question represents a new desig which was not specifically considered in drafting Standard No. 209. If the standard as written creates problems, the manufacturer may wish to consider submitting a petition for rulemaking to amend the standard to establish special test procedures.; Your letter suggests that there may be a conflict between sectio S7.4.2 of Standard No. 208, *Occupant Crash Protection*, and Standard No. 209's 0.2 pound retraction force requirement (section S4.3(j)). However, section S7.4.2 of Standard No. 208 only applies to automatic belt systems, while section S5.3(j) of Standard No. 209 only applies to active belt systems. Therefore, there can be no conflict.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1253OpenMr. J. T. Monk, Director of Engineering, Taylor Machine Works, Inc. P.O. Box 150, Louisville, MS 39339; Mr. J. T. Monk Director of Engineering Taylor Machine Works Inc. P.O. Box 150 Louisville MS 39339; Dear Mr. Monk: This is in reply to your letter of August 6, 1973, in which you as whether a sample certification label you enclosed will conform to NHTSA Certification regulations (49 CFR Part 567). We assume from the weight ratings specified in the sample that the trailer is a semitrailer.; As we indicated to you in our letter of June 26, 1973, the regulation do not provide for the listing of inflation pressure with the tire size designation, and the inflation pressure you have included should not appear in its present location on the label. You may, if you wish, include it following all the required information.; Apart from this item, a label similar to that you have submitted affixed in both an appropriate manner and location, will conform to Part 567.; We are happy to have been of assistance. Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4401OpenChristine Cottle, Office Administrator, Classic Auto Accessories, 1029 Sixth Avenue South, Seattle, WA 98134; Christine Cottle Office Administrator Classic Auto Accessories 1029 Sixth Avenue South Seattle WA 98134; Dear Ms. Cottle: This letter responds to your inquiry of June 30, 1987, where you as for information 'regarding any federal regulation that may apply to or restrict the use of items which might be suspended from the centered rear view mirror in an automobile or truck.' In your letter, you refer specifically to 'decorations' such as hanging dice and air fresheners, and express your company's wish 'to avoid liability for any obstruction of vision which might occur as the result of the use of such items.' Your letter does not say whether you manufacture the kinds of products you list, or install these kinds of products in motor vehicles.; First, please be aware that the National Highway Traffic Safet Administration (NHTSA) has authority to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. NHTSA does not approve vehicles or equipment, nor does the agency endorse any commercial products. Instead, the National Traffic and Motor Vehicle Safety Act establishes a certification process under which each manufacturer must certify that its product meets agency safety standards or other applicable standards. Periodically, NHTSA tests whether vehicles or equipment comply with these standards, and may investigate alleged safety-related product defects.; A product would fall under our agency's jurisdiction if it is an ite of 'motor vehicle equipment' as that term is defined in S102(4) of the National Traffic and Motor Vehicle Safety Act. Section 102(4) defines 'motor vehicle equipment' in relevant part as follows:; >>>...any system, part, or component of a motor vehicle as originall 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 an 'accessory,' th agency assesses two factors: first, whether the item has no ostensible purpose other than use with a motor vehicle, and second, whether the item is intended to be used principally by ordinary users of motor vehicles. The kinds of products you list do not fall within this framework, and therefore NHTSA does not regard them as items of motor vehicle equipment subject to our regulation.; There is one section of the Safety Act that I would call to you attention. Among other things, S108(a)(2)(A) of the Act states that:; >>>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...<<<; If your company is among the persons or performs the kinds o operations in S108(a)(2)(A), then it may not remove, disconnect, or degrade the performance of safety equipment or designs installed in compliance with an applicable Federal safety standard. For example, you could not install any item in a motor vehicle that would render inoperative Standard 111 (Rearview Mirrors) 'field-of-view' specifications. (I enclose a copy of that Standard.); However, S108(a)(2)(A) does not apply to vehicle owners. Therefore owners may install items in their own cars, even if doing so involves removal, disconnection or degradation of safety equipment or designs, without violating S108(a)(2)(A). Further, neither the manufacture of such items nor their sale to vehicle owners violates that prohibition.; Please note that a violation of S108 or of any regulation issued unde it is punishable by a civil fine of up to $1000 for a related series of violations.; Finally, you may wish to consult the laws of the various States t determine whether there are any limitations in their laws on the hanging of objects from inside rearview mirrors.; I hope you find this information helpful. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam0911OpenMr. Charles P. Madigan, Sunspot Products Company, 25162 Mound Road, Warren, MI, 48091; Mr. Charles P. Madigan Sunspot Products Company 25162 Mound Road Warren MI 48091; Dear Mr. Madigan: Your letter of October 30, 1972, to Mr. James H. Wakelin, Jr. regarding a flammability test cabinet, was forwarded to us for reply.; Federal Motor Vehicle Safety Standard (FMVSS) No. 302 specifies cabinet for flammability testing with the test specimens in a horizontal position. There is no FMVSS for a vertical test method. A copy of FMVSS No. 302 is enclosed.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam1603OpenRobert Gonce, Esq., O'Bannon & Gonce, 402 South Pine Street, Florence, Alabama 35630; Robert Gonce Esq. O'Bannon & Gonce 402 South Pine Street Florence Alabama 35630; Dear Mr. Gonce: #In response to your request I have enclosed a copy o Federal Motor vehicle Safety Standard No. 109, new Pneumatic Tires (49 CFR S571.109) as it appears in the current edition of the *Code of Federal Regulations.* #The table listing load and inflation values for the G78-15 tire size designation is Table I-J of Appendix A. Except for the addition of test loads at 16 and 18 psi, the load and inflation information for the G78-15 tire size designation has not changed since the first publication of the information on April 18, 1968 (33 FR 5949), a copy of which is also enclosed. #Yours truly, Richard B. Dyson, Acting Chief Counsel; |
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ID: aiam4952OpenMr. David Klopp Freedman Seating Company 4043 N. Ravenswood Chicago, IL 60613; Mr. David Klopp Freedman Seating Company 4043 N. Ravenswood Chicago IL 60613; Dear Mr. Klopp: This responds to your fax of January 30, 1992 to Mar Versailles of my staff asking whether the anchorage strength test in Standard No. 210, Seat belt assembly anchorages, requires simultaneous testing of seat belt anchorages located on the seat frame of a seat having multiple seating positions. Under the current requirements of S4.2.4 of Standard No. 210, only floor-mounted anchorages are subject to simultaneous testing. The requirement applicable to vehicles with seat- mounted safety belt anchorages, S4.2.4 of Standard No. 210, has been changed, effective September 1, 1992. For a vehicle manufactured on or after that date, seat-mounted anchorages will be tested simultaneously by loading all anchorages common to the same occupant seat. I hope you find this information helpful. If you have any further questions please contact Mary Versailles at this address or by phone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam2185OpenMr. Roger R. King, King Company Inc., 4308 Stewart Avenue, Wausau, WI 54401; Mr. Roger R. King King Company Inc. 4308 Stewart Avenue Wausau WI 54401; Dear Mr. King: This is in response to your letter of November 19, 1975, concernin tire registration numbers, and in confirmation of your telephone conversation with Mr. Schwartz of this office.; Thank you for your suggestion that the tire identification numbe appear on both sidewalls of tires which are delivered already mounted on a vehicle. It is being reviewed by our technical staff, and we will advise you by letter of our decision in this matter.; In answer to your question concerning the types of vehicles covered b the term 'motor vehicle,' 'motor vehicle' is defined in the National Traffic and Motor Vehicle Safety Act of 1966 as 'any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails.'; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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.