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: aiam4579OpenConrad S. Brooks, Engineering Manager Fisher Engineering 12 Water Street P.O. Box 529 Rockland, ME 04841; Conrad S. Brooks Engineering Manager Fisher Engineering 12 Water Street P.O. Box 529 Rockland ME 04841; "Dear Mr. Brooks: This responds to your December 1, 1988, lette concerning the applicability of Federal regulations to motor vehicles to which a detachable snowplow is attached. I will respond to each one of your specific questions below. Question One: 'Please confirm in writing that the substructure for a snowplow mounting that is permanently attached to a four wheel drive vehicle may be attached to and be forward of the front bumper without violating any existing or proposed vehicle safety standard.' Response: We cannot make such a blanket statement. The weight and the location of the substructure might affect the vehicle's compliance with Standard No. 105, Hydraulic Brake Systems (49 CFR /571.105) and Standard No. 120, Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars (49 CFR /571.120). Any person attaching such a substructure before the first retail sale of the vehicle would have to certify that the vehicle with the substructure attached complied with all applicable safety standards. Any commercial business attaching such a substructure after the first retail sale of the vehicle must ensure that the addition of the substructure does not 'render inoperative' the vehicle's compliance with any safety standard. Commercial businesses are prohibited from 'rendering inoperative' a vehicle's compliance with any safety standard by section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(2)(A)). Question Two: 'Is the snowplow blade, being detachable and used only a few hours each year, considered as part of the vehicle payload when it is attached?' Response: None of our regulations define or otherwise mention the term 'vehicle payload.' We assume that you are referring to calculation of the vehicle's weight when you speak of its 'payload.' If this is the case, we have definitions of many different weight calculations set forth in 49 CFR /571.3 and in our individual safety standards. Some of these weight calculations would exclude a detachable snowplow blade. For instance, 'unloaded vehicle weight' is defined in 49 CFR /571.3 as: the weight of a vehicle with maximum capacity of all fluids necessary for operation of the vehicle, but without cargo, occupants, or accessories that are ordinarily removed from the vehicle when they are not in use. (emphasis added). In a January 18, 1977, letter to Mr. D.J. Henry, the agency stated that portions of a snowplow that would ordinarily be removed from the vehicle when they are not in use (such as a snowplow blade) would not be included in calculating the 'unloaded vehicle weight.' If you would identify the particular weight calculation in which you are interested, we would be pleased to tell you whether the weight of a detachable snowplow blade should be included in that particular weight calculation. Question Three: 'Does this exempt a vehicle, with the blade attached and raised, from having to meet the Front Gross Axle Weight Rating restrictions?' Response: No. There are no exemptions from the gross axle weight ratings. 49 CFR /571.3 defines gross axle weight rating as 'the value specified by the vehicle manufacturer as the load carrying capacity of a single axle system, as measured at the tire-ground interfaces.' The vehicle manufacturer or any vehicle alterer must base its certification of the vehicle's compliance with all applicable safety standards on the assigned gross axle weight ratings. NHTSA answered the specific question of how detachable snowplow blades are considered in determining whether a vehicle is within its assigned gross axle weight ratings in a March 8, 1976, letter to Mr. Edward Green. In that letter, we stated that any determination of whether a vehicle was within its assigned gross axle weight rating would include the weight imposed on that axle system by a snowplow with the blade attached and raised. Question Four: Is there a specific limitation of what percent of the vehicle curb weight can be supported by the front axle? The Ford Truck and Body Builders Layout book specifies a maximum of 63 percent for the front axle. Response: None of our regulations, including the definitions of 'gross axle weight rating' and 'gross vehicle weight rating,' specify any weight distribution limitations or proportions for the front axle of a vehicle. The only issue for the purposes of our safety standards is whether the vehicle complies with all applicable standards when it is loaded to its assigned gross axle weight ratings. As long as the vehicle complies with our standards under those loading conditions, it makes no difference what proportion of the curb weight is assigned to each axle. We assume the reason that Ford's guidebook specifies a maximum of 63 percent of the vehicle's curb weight to be supported by the front axle is to ensure that the proportional load stopped by the vehicle's front and rear brakes will be such that the vehicle can be certified as complying with our braking standard. Any commercial entity that modified a Ford vehicle in such a way that more than 63 percent of the curb weight were supported by the front axle would have to certify that the modified vehicle complied with our braking standard, if the modification were made before the first retail sale of the vehicle, or make an initial finding that the modifications did not result in 'rendering inoperative' the vehicle's compliance with our braking standard, if the modification were made after the first retail sale of the vehicle. Question Five: If the portion of curb weight on the front axle is only dictated by vehicle performance, can NHTSA suggest a source for some general guidelines to avoid performance testing? Response: As noted in response to Question Four, vehicle performance is the only limitation on the proportion of curb weight that can be assigned to the front axle. For vehicles that are modified before the first retail purchase, the entity making the modifications can consult the instructions provided by the incomplete vehicle manufacturer. An example of these instructions is the Ford Truck and Body Builders Layout book to which you referred in your letter. Those instructions generally establish some limits on the parameters of the completed vehicle, such as its weight, height of center of gravity, and so forth. When the entity modifying the vehicle completes the vehicle within the limits established by the incomplete vehicle manufacturer, the modifier is not required to conduct its own testing or engineering analyses. When a vehicle is modified after its first retail purchase, the modifier could remain within the gross axle weight ratings and gross vehicle weight ratings labeled on the vehicle. If the modifier does so, it would not need to conduct any testing or engineering analyses. If you have any further questions or need more information on this subject, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam1281OpenMr. Dick Love, President, Cycraft Company, Inc., 111 Monument Circle, Suite 1200, Indianapolis, IN 46204; Mr. Dick Love President Cycraft Company Inc. 111 Monument Circle Suite 1200 Indianapolis IN 46204; Dear Mr. Love: This is in reply to your letter of September 17, 1973, concernin Standard No. 218, 'Motorcycle Helmets.' The questions you ask are restated below.; >>>1. 'Is the attachment of the symbol DOT sufficient in itself t certify that the helmet meets the requirements of this act or must the manufacturer have independent supporting data available?'; The DOT symbol, when attached to the helmet, is the manufacturer' certification of the helmet's conformity with the requirements of the standard. Accordingly, because the manufacturer is required to exercise due care that such certification is accurate and true in every material respect, he would have the data necessary to support his certification.; 2. 'Is any form of certification filing required by your Department? I so, is the manufacturer's statement alone sufficient or must independent test data be included?'; No certification filing is required by the Department. 3. 'Will your Department undertake or supervise the independent testin of helmets to verify compliance with the Act? If so, will there be a limit on the age of the helmet used? Will manufacturers be asked to supply the helmet for testing or will your Department secure them from other sources and if so, what sources? Will the regulations apply to helmets manufactured prior to March 1, 1974, but yet unsold as of or after the date?'; 4. 'Will manufacturers, distributors, or dealers holding inventorie which do not meet the requirements of the Act because they were made prior to March 1, 1974, be permitted to sell them, be required to dispose of them, be subject to penalty if they do sell them or exactly what?'; Once any Federal Motor Vehicle Safety Standard becomes effective violations of such regulations are federally enforced. The National Highway Traffic Safety Administration (NHTSA) will purchase motorcycle helmets after the helmet standard becomes effective and test them for compliance. The standard will apply only to helmets manufactured on or after its effective date, it will not apply to helmets manufactured before its effective date but sold to the public after that date.; 5. 'Will pressure sensitive labels applied to the exterior of th helmet meet regulations of S5.6.1, 1 through 6?'; The standard requires that the labeling be 'permanently' affixed to th helmet. This language prohibits the use of labels that can be removed easily by hand without tools or chemicals, or that are in a location where it appears that their removal is expected by the manufacturer.; 6. 'What are the penalties for failure to comply and upon wha determination will the manufacturer be deemed to not be in compliance with the Act?'(sic) What form of notice will be given, what procedures shall take place and what burden of proof will be placed upon the manufacturer?'; Under section 109(a) of the National Traffic and Motor Vehicle Safet Act of 1966, whoever violates any provision of section 108, or any regulation issued under the Act, including selling nonconforming equipment, shall be subject to a civil penalty of not more than $1,000 for each violation to a maximum of not more than $400,000 for any related series of such violations.<<<; If the NHTSA determines that a case of noncompliance does exist, the the manufacturer is asked by notice letter to show cause (1) why a civil penalty should not be imposed against him and (2) why he should not correct the noncompliance. Most noncompliance matters are settled at this informal stage. However, if the parties do not agree to a compromise settlement, a formal proceeding under section 113(e) of the Act will be commenced. The manufacturer will be furnished all of the evidence upon which the agency's determination of noncompliance is based. At the 113(e) proceeding the manufacturer will be allowed to present his views regarding the agency's position. The entire record, including the agency's investigation file and the submission of the manufacturer will be forwarded to the agency Administrator for final determinitation (sic). If the Administrator determines that the noncompliance exists, he will direct the manufacturer to issue the defect notifications as required by section 113 and 49 CFR Part 577, and to file a defect report as required by 49 CFR Part 573. In addition, the manufacturer will be directed to pay an appropriate civil penalty.; A copy of the National Traffic and Motor Vehicle Safety Act of 1966 i enclosed for your information.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4083OpenMr. Larry Alexander, Senior Product Manager, Consumer Products Division, Tuck Industries, Inc., Lefevre Lane, New Rochelle, NY 10801; Mr. Larry Alexander Senior Product Manager Consumer Products Division Tuck Industries Inc. Lefevre Lane New Rochelle NY 10801; Dear Mr. Alexander: This is in reply to your letter of October 1, 1985, asking whether an of your pressure sensitive tapes packaged for the automotive aftermarket are subject to any regulations of the National Highway Traffic Safety Administration. You have been asked by one of your customers to certify that your tape meets all applicable Federal motor vehicle safety standards and other regulations.; You provide four types of tapes: lens repair tape (for temporary us until a broken lens is replaced), hose repair tape (for temporary repair of leaks in water hoses), clear patch tape (for repair of upholstery), and carpet tape (used to hold carpets in place). This agency has jurisdiction over items of motor vehicle equipment, which are defined in part as:; >>>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 a motor vehicle....'<<<; Your tape could be regarded as an 'addition' to a motor vehicle bu even assuming that it is an item of motor vehicle equipment, there are no Federal motor vehicle safety standards that would apply to it. Therefore, no manufacturer certification is required, and you may so inform your customer. Further, any such certification could be viewed as a violation of the National Traffic and Motor Vehicle Safety Act by being certification that is false and misleading in a material respect, stating compliance with standards which are, in fact, non-existent.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3746OpenMr. Jeffrey A. Crawford, Q.A. Manager, Lyn-Mont Manufacturing Co., P.O. Box 11745, 4208 Clubview Drive, Fort Wayne, IN 46860; Mr. Jeffrey A. Crawford Q.A. Manager Lyn-Mont Manufacturing Co. P.O. Box 11745 4208 Clubview Drive Fort Wayne IN 46860; Dear Mr. Crawford: This responds to your letter concerning Safety Standard No. 106, *Brak Hoses*. You asked whether certain proposed labeling for brake hose assemblies would meet the labeling requirements of sections S7.2.3 and S7.2.3.1. As discussed below, the answer to your question is no.; By way of background information, this agency does not provid approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to assure that its products comply with applicable safety standards. The following opinion is based on the facts provided in your letter.; Sections S7.2.3 and S7.2.3.1 provide two options for the labeling o air brake hose assemblies made with end fittings that are attached by crimping or swaging. Section S7.2.3 states that such assemblies, except those assembled and installed by a vehicle manufacturer in vehicles manufactured by him, shall be labeled by means of a band around the brake hose assembly as specified in that paragraph, or, at the option of the manufacturer, by means of labeling as specified in section S7.2.3.1.; If the first option is chosen, using a band as specified in sectio S7.2.3, the band must include (a) the symbol DOT, and (b) the manufacturer designation. If the second option, specified in section S7.2.3.1, is chosen, the manufacturer designation must be placed on at least one end fitting of the assembly. (These sections also specify other requirements concerning labeling, such as size of letters, which are not relevant to this interpretation.); Your proposed labeling, placing the manufacturer designation on th band and the symbol DOT on the end fitting, would not meet the requirements of either of these options. If the first option is chosen, the symbol DOT must be placed on the band along with the manufacturer designation. If the second option is chosen, the manufacturer designation must be placed on the end fitting.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2854OpenMr. James Tydings, Specifications Engineer, Thomas Built Buses, Inc., 1408 Courtesy Road, P.O. Box 2450, High Point, NC 27261; Mr. James Tydings Specifications Engineer Thomas Built Buses Inc. 1408 Courtesy Road P.O. Box 2450 High Point NC 27261; Dear Mr. Tydings: This responds to your July 19, 1978, letter asking whether the State o California is preempted from requiring that all seats in school buses be forward facing.; Section 103(d) of the National Traffic and Motor Vehicle Safety Act o 1966 (the Act) (15 U.S.C. 1381 *et seq*.) specifies that no State shall have in effect a safety standard concerning an aspect of performance regulated by a Federal safety standard, unless the State standard is identical. The Act provides a limited exception to the above where a State or local municipality has a requirement which applies only to vehicles purchased for their own use and which imposes a higher standard of performance.; Standard No. 222, *School Bus Passenger Seating and Crash Protection* specifies that seats shall be forward facing except seats designed to transport the handicapped. Seats for the handicapped may be side facing to permit ease of access. The California standard requiring forward facing seats regulates the same aspect of performance, seat orientation, as the Federal standard. Since the California standard is not identical to the Federal standard and, in fact, conflicts the Federal standard, it is the opinion of the National Highway Traffic Safety Administration that it is preempted.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0869OpenMr. L. E. Maison, President, Monroe Standard, Inc., 118 Harding Way West, Galion, OH 44833; Mr. L. E. Maison President Monroe Standard Inc. 118 Harding Way West Galion OH 44833; Dear Mr. Maison: This is in reply to your letter of September 25, 1972, regarding th warning signal required under S5.1.5 of Motor Vehicle Safety Standard No. 121, Air Brake Systems.; Your reading of the second sentence of S5.1.5 is partially in error. I the visible low pressure warning signal is provided with a companion audible signal, the visible signal does not have to be within the driver's forward field of view. Under S5.1.5 a manufacturer may choose to install a visible signal within the driver's forward field of view, in which case he may omit the audible signal, or to install the signal outside the driver's forward field of view, in which case he must provide an audible signal. If a manufacturer provides a signal within the forward field of view, he may choose to provide an audible signal as well, but the section does not require him to do so.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2507OpenMr. W. G. Milby, Blue Bird Body Company, P. O. Box 927, Fort Valley, GA 31030; Mr. W. G. Milby Blue Bird Body Company P. O. Box 927 Fort Valley GA 31030; Dear Mr. Milby: This responds to your January 19, 1977, question whether th requirement of S5.2 of Standard No. 222, *School Bus Passenger Seating and Crash Protection*, for a restraining barrier of specified size in front of certain designated seating positions necessitates the provision of an additional barrier surface in front of those portions of a bench seat that do not form part of the designated seating positions. You describe a front-row two-passenger bench seat in a bus (with a seat back that extends beyond the bench to provide adequate restraint for a three-passenger seat aft of it) and ask about the restraining barrier that is required in front of the two- passenger front-row seat.; Paragraph S5.2.2 requires that the perimeter of the restraining barrie coincide with or lie outside of the perimeter of the seat back of the seat for which it is required. This means that the restraining barrier must coincide with or lie outside of the perimeter of the seat back of the desinnated (sic) seating position or positions for which it is required. Therefore, a seat with only two designated seating positions must only be equipped with a restraining barrier in front of those two seating positions.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam5368OpenMr. Norman Duncan President Study-Tech, Inc. 603 South River Road des Plaines, IL 60016; Mr. Norman Duncan President Study-Tech Inc. 603 South River Road des Plaines IL 60016; "Dear Mr. Duncan: The Federal Highway Administration has forwarded you letter of March 10, 1994, for reply. You request 'an interpretation of the existing vehicle code as it may apply to a safety- warning system that our corporation has devised.' Our agency issues the Federal Motor Vehicle Safety Standards that apply to new motor vehicles, pursuant to the National Traffic and Motor Vehicle Safety Act ('the Act'). Our Standard No. 108 Lamps, Reflective Devices, and Associated Equipment is the regulation that governs the performance of lighting equipment that is required on new motor vehicles and determines whether optional lighting equipment is acceptable. As you have described it, the 'Early-Warning Slow Down Safety Light' will automatically be activated when a vehicle decelerates. The system will operate through the stop lamps, but, alternatively, it could employ separate lamps mounted on the rear deck. Your system is similar to others which have been suggested over the years, and we therefore do not feel that a demonstration is necessary as you have offered. With respect to operation of your system through the stop lamps, as you will see from our letter of October 22, 1993, to Dr. Cehelnik, a copy of which I have enclosed, automatic activation of the stop lamps is not permitted by Standard No. 108 which allows the stop lamps to operate only when the brake pedal is applied. As for operation of your system through a separate lamp system, paragraph S5.1.3 of Standard No. 108 permits supplementary lighting equipment provided that it does not impair the effectiveness of lighting equipment required by the standard. Were your separate warning system to utilize red lenses, we believe that it could impair the effectiveness of the required stop lamps by sending at times a false signal, not every deceleration is followed by braking, and the operation of your system when not followed by brake application activating the stop lamps could be confusing to a following driver. On the other hands, if your system utilized amber lenses, we believe that impairment would be unlikely to exist because the public associates this color with the need for caution. The Act itself governs acceptability of your system in the aftermarket (i.e., installed on vehicles in use). Section 108(a)(2)(A) prohibits manufacturers, dealers, distributors, and motor vehicle repair businesses from knowingly rendering inoperative, in whole or in part, any device or element of design installed in accordance with Standard No. 108 and all other safety standards. We interpret this where possible as equating inoperability with impairment. Thus, we would view installation of your system by the persons named above as violative of the Act if it operated through the stop lamp system or if it were a separate lamp system with red lenses. Even where a supplementary lighting system may be permitted under Federal laws and regulations, it remains subject to the laws of the individual states where the system will be operated. We are unable to advise you on State laws, and suggest that you write for an opinion to: American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam0490OpenMr. Thomas G. Maylone, General Manager, Trike Motor Company, P.O. Box 1044, Pontiac, MI 48056; Mr. Thomas G. Maylone General Manager Trike Motor Company P.O. Box 1044 Pontiac MI 48056; Dear Mr. Maylone: You wrote some time ago to request information concerning th application of various motor vehicle safety standards to passenger cars with curb weights of less than 1,000 pounds. Contrary to the information you obtained from *Motor Trend*, this category of passenger cars is still exempt from the standards. There is a possibility that at some future date the exemption granted by 571.7(a) will be changed or revoked, but any such action can be taken only after opportunity for public comment.; Please advise us if you feel it necessary to have your remainin questions answered.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2157OpenMargaret A. Freeston, Consumer Product Safety Commission, Washington, DC, 20207; Margaret A. Freeston Consumer Product Safety Commission Washington DC 20207; Dear Ms. Freeston: This is in response to your letter of February 10, 1976, in which yo request our opinion concerning the applicability of Federal Motor Vehicle Safety Standard No. 302 to mattresses.; You are correct in saying that the amendment to S4.2 of Standard No 302, promulgated on March 31, 1975 (40 FR 14318), extends the coverage of the standard to '(a)ny portion of a single or composite material which is within 1/2 inch of the occupant compartment air space...' S4.1 of the standard provides, however, that '(t)he portions described in S.4.2 of the following components shall meet the requirements (of the standard)....' S4.1 then lists the components to which the standard applies. While mattress covers are included in the listing, mattresses are not. Consequently, Standard No. 302 does not apply to mattresses as such.; You should be aware that a notice of proposed rulemaking was als issued on March 31, 1975 (40 FR 14340) proposing that any material within 1/2 inch of the occupant compartment air space meet the requirements of the standard. Should this proposal be adopted, mattresses would fall within the purview of Standard No. 302. I have enclosed a copy of the proposed rule for your further information.; Yours truly, Richard B. Dyson, Assistant 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.