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: aiam3724OpenMr. Chuck Howard, President, Safety Alert Co., Inc., 1667 9th Street, Santa Monica, CA 90404; Mr. Chuck Howard President Safety Alert Co. Inc. 1667 9th Street Santa Monica CA 90404; Dear Mr. Howard: This is in reply to your letter of June 28, 1983, occasioned by wha you believe is our misconception of the way your 'Safety Alert' system operates. In my letter of June 17 I stated that 'Safety Alert', which was intended to flash a yellow bulb installed in the backup lamp system, would create a noncompliance with Standard No. 108 which requires backup lamps to be white in color and steady burning when in use. You now bring it to our attention that your system does not alter the normal operation of the backup lamps which are steady burning when a vehicle is in reverse, even when 'Safety Alert' is installed.; We understood this when we advised you that you could use 'Safet Alert' through any rear lighting system which Standard No. 108 allows to flash for signalling purposes such as the hazard warning or turn signal systems. The converse of this is that 'Safety Alert' cannot be used through any rear lighting system that Standard No. 108 requires to be steady-burning when in use, such as the backup lamp system, even though when used as a backup lamp it is steady burning. I am sorry this was not clear to you.; We are unaware that any foreign manufacturer is failing to comply wit Standard No. 108 by installing a backup lamp system that 'reflects amber' as you have told us.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2836OpenMr. Charles Pfaff, Motor Vehicle Administration, Maryland Department of Transportation, 6601 Ritchie Highway, N.E., Glen Burnie, MD 21062; Mr. Charles Pfaff Motor Vehicle Administration Maryland Department of Transportation 6601 Ritchie Highway N.E. Glen Burnie MD 21062; Dear Mr. Pfaff: Thank you for your letter of June 16, 1978, requesting our opinion o whether the Maryland Certificate of Title meets the Federal requirements for the odometer disclosure form as set forth in 49 CFR Part 580.; The proposed Certificate of Title which you enclosed with your lette differs from the Federal odometer disclosure form in the following ways:; (1) The Maryland Certificate of Title shortens the reference to th Federal law,; (2) the set of certifications relating to the distance that the vehicl has travelled are shortened by adopting language similar to that recommended by the American Association of Motor Vehicle Administrators,; (3) the certifications relating to alteration of the odometer ar deleted, and; (4) although the transferee is required to sign the statement, th signature does not specifically acknowledge receipt of a copy of the statement, as is required by the Federal law.; The National Highway Traffic Safety Administration (NHTSA) has reviewe Maryland's proposed Certificate of Title and has determined that it will further the goal of the Federal odometer law, despite its differences from the Federal form. Therefore, pursuant to 49 CFR S 580.4(f)(2), I hereby grant your request to use Maryland's Certificate of Title as a substitute for the Federal odometer disclosure form.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam5023OpenMr. Neil Friedkin Attorney at Law 325 Exterior Street Bronx, NY 10451; Mr. Neil Friedkin Attorney at Law 325 Exterior Street Bronx NY 10451; "Dear Mr. Friedkin: This responds to your follow-up letter to th agency requesting that the agency provide 'the applicable 1986 standard for convertible passenger cars.' In an earlier letter, you had asked about our regulations with respect to converting a vehicle from a hardtop to a convertible. I am pleased to have this opportunity to respond to your inquiry. To begin, there is no single standard applicable to convertible passenger cars, or any other motor vehicles. Instead, the National Highway Traffic Safety Administration (NHTSA) is authorized under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., Safety Act) to issue safety standards applicable to new motor vehicles and items of motor vehicle equipment. We have exercised this authority to establish many standards that apply to passenger cars, including convertible passenger cars. These standards, which are collectively called the Federal motor vehicle safety standards, are set forth in 49 CFR Part 571. They cover many different vehicle systems, including controls and displays, vehicle lighting, braking, occupant crash protection, and fuel system integrity. As you review the safety standards in Part 571 to see which aspects of performance are of particular interest to you, you will see that the standards are generally identical for passenger cars and convertible passenger cars. There are some differences, however, including the permissible location for the center high mounted stop lamp (S5.3.1.8 of Standard No. 108, Lamps, Reflective Devices and Associated Equipment) and the inapplicability of the roof crush standard to convertibles (S3 of Standard No. 216, Roof Crush Resistance). Additionally, Standard No. 208, Occupant Crash Protection, required the front outboard seating positions of 1986 passenger cars that were not equipped with automatic crash protection (either air bags or automatic belts) to be equipped with a lap/shoulder belt and all other seating positions to be equipped with either a lap belt or a lap/shoulder belt (S4.1.2.3.1 of Standard No. 208). However, convertible passenger cars were permitted to offer either a lap belt or a lap/shoulder belt at every designated seating position, including the front outboard positions (S4.1.2.3.2 of Standard No. 208. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0221OpenJohn S. Cushman, Esq.,Special Assistant Attorney General, Consumer Division, 102 State Capitol, St. Paul, Minnesota 55101; John S. Cushman Esq. Special Assistant Attorney General Consumer Division 102 State Capitol St. Paul Minnesota 55101; Dear Mr. Cushman: Your letter of February 16, 1979, transmitting Mr. John M. Schneider' letter, concerning tire selection for his 25,500-lb. GVW Truck, to the Federal Trade Commission has been referred to the National Highway Safety Bureau for reply.; There are no Federal standards at the present time for Tire Selectio and Rims for trucks. We are currently in the rule making phase to establish such a standard, however, we anticipate the effective date of this standard to be more than a year in the future.; The lack of Federal Standards in no way relieves a vehicle manufacture from his responsibility to design vehicles with equipment that will perform safely. this was evidenced in recent negotiations between General Motors and the National Highway Safety Bureau on a problem concerning three piece Kelsey-Hayes wheels. As you may know, at present, there are no standard covering wheel performance.; Sincerely, Rodolfo A. Diaz, Acting Associate Director, Motor Vehicl Programs; |
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ID: aiam5473OpenMr. Ed Irvine Midwest Conservation Systems P.O. Box 397 Silver Lake, KS 66539; Mr. Ed Irvine Midwest Conservation Systems P.O. Box 397 Silver Lake KS 66539; Dear Mr. Irvine: This responds to your letter asking whether a newl manufactured commercial utility trailer must be equipped with an emergency breakaway system. You state that your customer wishes to purchase a trailer without the battery powered breakaway system that comes with the trailer. Instead, you would like to install your solar energized breakaway system. In a December 7, 1994 telephone conversation with Mr. Marvin Shaw of my staff, you stated that the trailers in question are typically small utility trailers that do not rely on the use of air pressure. I am pleased to have this opportunity to explain the applicable requirements issued by this agency, the National Highway Traffic Safety Administration (NHTSA). You may also wish to request an interpretation of 49 CFR 393.43 from the Federal Highway Administration (FHWA), which is the agency that issued that regulation. By way of background information, NHTSA and FHWA are both part of the United States Department of Transportation. Each agency has the authority to issue regulations related to your question. NHTSA, which regulates newly manufactured vehicles, has the authority to issue Federal motor vehicle safety standards (FMVSS) which apply to new motor vehicles and new items of motor vehicle equipment. FHWA, which regulates the use of commercial motor vehicles, has the authority to issue Federal Motor Carrier Safety Regulations (FMCSRs), which are applicable to commercial motor vehicles and their operators. We have referred your letter to the Federal Highway Administration's (FHWA) Office of Motor Carrier Standards, since that agency issued 49 CFR 393.43. While NHTSA has the authority to issue FMVSSs, the agency has not issued any FMVSS that would directly affect the braking performance of a small utility trailer, unless the trailer relies on air pressure. Therefore, if the trailers in question are not air braked vehicles, then you would not need to certify that such a trailer's braking performance complies with an FMVSS, since no applicable FMVSS exists. Please note that your solar energized trailer breakaway system would be considered 'motor vehicle equipment' within the meaning of the statute administered by NHTSA. If this system contained a defect (either in manufacture, design, or performance) that relates to motor vehicle safety, the manufacturer would be required to conduct a recall campaign to notify owners and to remedy the defect free of charge. I hope this information is helpful. If you have any questions about NHTSA's safety standards, please feel free to contact Marvin Shaw at this address or by telephone at (202) 366-2992. If you wish to contact someone in the FHWA's Office of Chief Counsel concerning the motor carrier standards, please call Charles Medalen at (202) 366-1354. Sincerely, Philip R. Recht Chief Counsel; |
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ID: aiam1963OpenMr. Gary W. Walters, 152 Westwood Drive, Clarion, Pennsylvania 16214; Mr. Gary W. Walters 152 Westwood Drive Clarion Pennsylvania 16214; Dear Mr. Walters: This is in response to your letter requesting information concernin standards that relate to the construction of a pick-up camper.; Although your letter is unclear on this point, we assume that you questions relate to the building of a single slide-in camper for your own use. If this is the case, the only standards with which you must comply are Standard No. 126, *Truck-camper loading*, and Standard No. 205, *Glazing materials*. In addition, your camper should be certified in accordance with 49 CFR Part 567.; The NHTSA can provide no information concerning methods of constructio of these or other items of motor vehicle equipment.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5189OpenMr. Ray Kesler Kesler Research Enterprises 5508 Cahuenga Blvd. North Hollywood, CA 91601; Mr. Ray Kesler Kesler Research Enterprises 5508 Cahuenga Blvd. North Hollywood CA 91601; "Dear Mr. Kesler: This responds to your follow-up letter to the agenc in which you request further interpretation of the requirements in Standard No. 111 relating to convex mirrors. Specifically, you asked about how section S5.4.1, which limits the radii of curvature's permissible variance, relates to S12, which specifies the procedures for determining a convex mirror's average radius of curvature. I am pleased to have this opportunity to respond to your request. As Marvin Shaw of my staff informed your associate Lawrence Hufstedler in a telephone conversation, section S12 sets forth a detailed multi-step procedure for calculating a convex mirror's average radius of curvature. The first step is to take ten readings on the mirror surface with a 3-point linear spherometer as specified in Figure 1 of the Standard. (See S12.1.) The second step is to convert each of the ten readings to a 'radius of curvature calculation' using Table 1. (See S12.5.) The third step is to calculate the 'average radius of curvature' by adding all 10 radius of curvature calculations and dividing by 10. (See S12.6.) Mr. Hufstedler asked how S5.4.1 affects the calculations. That section states 'none of the radii of curvature readings shall deviate from the average radius of curvature by more than 12.5 percent.' This means that some of the radii of curvature readings may be up to 12.5 percent different than the average radius of curvature. In numerical terms, this means that if a mirror had an average radius of curvature of 36 inches a given radii of curvature reading could be as low as 31.5 inches and as high as 40.5. I hope this information is helpful. Please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992 if you have any further questions or need additional information. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0671OpenMr. George C. Nield, Engineering Advisor, Messrs. Busby Rivkin Sherman Levy and Rehm, 816 Connecticut Avenue, N.W., Washington, DC 20006; Mr. George C. Nield Engineering Advisor Messrs. Busby Rivkin Sherman Levy and Rehm 816 Connecticut Avenue N.W. Washington DC 20006; Dear Mr. Nield: In your letter of April 5, you ask whether certain items of lightin equipment that you listed must be certified as conforming to applicable Federal standards, even though the assemblies of which they are a part may require certification.; This will confirm your understanding that the listed items need not b certified. The items of lighting equipment requiring certification are those equipment items specified in Tables I and III of Standard No. 108.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4632OpenMr. Mike Sazio S.C. Manufacturing, Inc. 11879 Woodbury Avenue Garden Grove, CA 92643; Mr. Mike Sazio S.C. Manufacturing Inc. 11879 Woodbury Avenue Garden Grove CA 92643; "Dear Mr. Sazio: This responds to your letter concerning th application of our regulations and Federal motor vehicle safety standards to your company's manufacture of 'convertible vinyl tops for Jeeps and similar vehicles.' I regret the delay in responding. You asked which Federal safety standards apply to these convertible tops that you sell in both the new vehicle market and the aftermarket. You were especially interested in standards for 'windows and door handles.' There are two Federal safety standards (copies enclosed) that would apply to your product: (1) Standard No. 205, Glazing Materials, and (2) Standard No. 302, Flammability of Interior Materials. While the brevity of the description of your product makes it difficult for us to determine whether our standard for door handles (Standard No. 206, Door Locks and Door Retention Components) applies, we believe that the standard does not apply to your product because the tops, which apparently incorporate doors, are readily removable. By way of background information, the National Highway Traffic Safety Administration (NHTSA) has the authority under the National Traffic and Motor Vehicle Safety Act (copy enclosed) to establish Federal motor vehicle safety standards for new motor vehicles and items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle 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. This process requires each manufacturer to determine in the exercise of due care that its products meet all applicable Federal requirements. The agency periodically tests vehicles and equipment for compliance with the standards, and also investigates other alleged safety-related defects. If you or the agency determines that a noncompliance or safety-related defect exists, you are obligated to notify purchasers of your product and remedy the problem without charge. Manufacturers who fail to provide notification of or remedy for a defect or noncompliance may be subject to a civil penalty of up to $1,000 per violation. (A general information sheet describing manufacturers' responsibilities under the Safety Act is enclosed.) The Safety Act defines the term 'motor vehicle equipment' as follows: 'Motor vehicle equipment' means any system, part, or component of a motor vehicle as originally 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 ...' (/102(4)) This definition includes the product your company manufactures since the convertible tops are components manufactured and sold either as a replacement or improvement of the convertible top or as an addition to vehicles that have no existing top. Since your product is considered an item of motor vehicle equipment, S.C. Manufacturing Inc., as the manufacturer of the equipment, must ensure that the convertible tops comply with all applicable Federal motor vehicle safety standards and contain no safety-related defects. If your product contains glazing material, Standard No. 205 (49 CFR /571.205, Glazing Materials) directly applies to that glazing material. Standard No. 205 is an equipment standard which sets performance requirements for glazing materials used in new motor vehicles and glazing materials sold as items of motor vehicle equipment, including glazing used in convertible tops. Any glazing in the convertible tops that your company manufactures for new or used vehicles must therefore conform to the applicable specifications set forth in Standard No. 205. The standard establishes both performance requirements, including those regulating the light transmittance and abrasion resistance of glazing, and labeling requirements applicable to the glazing used in your product. If your convertible top is added to a new vehicle, i.e., before the vehicle is sold for the first time to a consumer, then it must comply with Standard No. 302, Flammability of Interior Materials (49 CFR /571.302). Standard No. 302 applies to certain vehicle occupant compartment components, including convertible tops, on new completed motor vehicles. Persons selling new vehicles equipped with your convertible top must ensure that the vehicles, including your top, conforms to Standard No. 302. Generally speaking, while the requirements of Standard No. 302 apply to convertible tops incorporated in new vehicles, they do not apply to convertible tops added to used vehicles, i.e., vehicles which have been sold for the first time to a consumer. Under this general rule, you are permitted to sell aftermarket convertible tops that do not comply with Standard No. 302 to vehicle owners who will add them to their used vehicles even if the addition of the top by the vehicle owners caused the vehicles to no longer comply with Standard No. 302. This general rule is, however, limited by the application of the provisions of /108(a)(2)(A) of the Vehicle Safety Act. That section specifies: 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative ... 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 ...' This section requires manufacturers, distributors, dealers or motor vehicle repair businesses (i.e., any person holding him or herself out to the public as in the business of repairing motor vehicles or motor vehicle equipment for compensation) installing your top on new or used vehicles to ensure that the addition of the apparatus would not negatively affect the compliance of any component or design on a vehicle with applicable Federal safety standards. For example, the commercial entity must ensure that the addition of the top does not degrade from the safety provided by flammable-resistant materials in the vehicle's interior compartment which have been installed in accordance with Standard No. 302. Installation of rapidly burning materials could vitiate the compliance of the materials which were present in the vehicle at the time of its sale to the first consumer and were certified as meeting FMVSS No. 302. Section 109 of the Act specifies a civil penalty of up to $1,000 for each violation of section 108. You should note that section 108(a)(2)(A) is not limited to Standard No. 302, but applies also to any modification of Federally-required safety systems or devices on new or used vehicles. Section 108(a)(2)(A) prohibits rendering inoperative the compliance of devices or elements of design with any applicable Federal safety standard. Thus, a commercial entity would be permitted to install your product only if the modification would not destroy or degrade from a vehicle's compliance with any applicable Federal requirements, such as those for lamps and reflective devices (Standard No. 108). Standard No. 206 applies to new vehicles, but not to new aftermarket motor vehicle equipment. Therefore, the doors on aftermarket Jeep top covers would not have to meet the standard. Further, doors on new Jeep vehicles would not have to meet the standard if they are 'designed to be easily attached to or removed from' the vehicle, as provided in paragraph S4 of Standard No. 206. To summarize the above discussion, any glazing in the convertible tops you manufacture must meet applicable requirements of Standard No. 205 regardless of whether the tops are sold in the aftermarket or to new vehicle purchasers. The effect of Standard No. 302 on your product depends on the circumstances surrounding installation of the product in new and used motor vehicles. If the convertible top does not meet Standard No. 302, the top cannot be installed in vehicles by any commercial business listed in /108(a)(2)(A) of the Safety Act. However, these convertible tops may legally be installed in vehicles by the owners of the vehicles. Your company would still have the responsibility under the Vehicle Safety Act to recall and remedy its products which are determined to contain a defect relating to motor vehicle safety, even if the convertible tops were installed by vehicle owners themselves. I hope this information is helpful. In addition to the materials described above, I have also enclosed an information sheet describing generally your responsibilities under the Vehicle Safety Act. Please contact my office if we can be of further assistance. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosures"; |
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ID: aiam1430OpenMessrs. Nebe and Gartner, Continental Gummi-Werke, Aktiengeselischaft, Postfach 169, 3 Hannover, Germany; Messrs. Nebe and Gartner Continental Gummi-Werke Aktiengeselischaft Postfach 169 3 Hannover Germany; Gentlemen: This is in reply to your letter of January 29, 1974, raising certai questions about the effective date (September 1, 1974) of the Uniform Tire Quality Grading regulation. You pose two hypothetical questions, asking whether tires must be quality graded when they are to be placed on vehicles manufactured or imported after September 1, 1974. In the first situation, the tires are manufactured in July 1974, while the vehicle is manufactured in August 1974 and imported in October 1974. In the second, the tires are manufactured in August 1974, the vehicle is manufactured in September 1974 and imported in November 1974.; The Quality Grading regulation applies to tires rather than vehicles Its effective date of September 1, 1974, means that all passenger-car tires manufactured on or after that date must be graded in accordance with the regulation. There is no requirement, however, that vehicle manufacturers must use tires manufactured after that date. In each hypothetical question you present, the tires are manufactured before September 1, 1974, and therefore are not required to be graded. The date of manufacture or importation of the vehicle is immaterial.; 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.