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: aiam3591OpenDwight Hicks, Jr., 1208 Balthis Drive, Apt. B, Gastonia, NC 28052; Dwight Hicks Jr. 1208 Balthis Drive Apt. B Gastonia NC 28052; Dear Mr. Hicks: This responds to your recent inquiry regarding the applicability o Federal Motor Vehicle Safety Standard No. 125 to a warning device you plan to manufacture. That device is a rectangular sign with a base. The sign has the word 'HELP' in reflective letters on its surface and is designed to be illuminated by a cyalume light stick attached to the top of the sign. The sign is intended either to be mounted on a vehicle or to be erected on the road.; Section 3 of Standard 125 provides that the standard does not apply t warning devices which have 'self-contained energy sources' used to illuminate the device. Although the cyalume light stick used in your device would not provide a very bright source of illumination, the light stick would constitute such an energy source. Therefore, the warning device you describe does not appear to be subject to that standard. This conclusion applies only to the device as described in your submission to us. Subsequent design modifications regarding this energy source could change the agency's conclusion.; With regard to your question as to a recommended color to be used i your sign, section 5.3 of Standard 125 specifies the colors the agency has determined to be most appropriate for use in warning devices. We recommend that you use those colors.; Page 3 of your submission to us includes what appears to b instructions to users of your device. Those instructions state that failure to attach the light sticks to the sign would be a violation of our standards. Neither Standard 125 nor the statute under which it was issued applies to users of warning devices. Instead, they apply to the manufacturers, distributors and sellers of warning devices. These parties are prohibited from manufacturing or selling warning devices which, although subject to the standard, do not comply with our standard. Therefore, we urge deleting the last sentence of the first numbered paragraph on page 3.; If you have further questions on this matter, feel free to contact us. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5395OpenMr. Donald P. Green 809 Huasna Road Arroyo Grande, CA 93420; Mr. Donald P. Green 809 Huasna Road Arroyo Grande CA 93420; Dear Mr. Green: This responds to your letter to this agency askin whether there is a State or Federal regulation prohibiting the use of passenger radial tires on recreational 'pull type' trailers. I regret the delay in responding. You explain that you were told by various tire dealers that radial tires should not be used on trailers because the soft sidewalls of radial tires could cause an uncontrollable swaying that could result in a serious accident. You then state that while towing a trailer mounted with four radial tires, you were caught in a crosswind which caused the trailer to jackknife, resulting in a serious accident. To begin, I am sorry to hear about your accident but am thankful that no one was hurt. The tire safety standards and regulations issued by the National Highway Traffic Safety Administration (NHTSA) require tires to be able to safely carry the load on a vehicle and to be labeled with important safety information, such as tire size, construction, and inflation pressure. There is nothing in our standards or regulations that prohibits the use of passenger car radial tires on trailers. In fact, Federal Motor Vehicle Safety Standard No. 120, 'Tire selection and rims for motor vehicles other than passenger cars,' expressly permits the use of passenger car tires on vehicles like trailers, provided that adjustment is made to the tire's load-carrying capacity. NHTSA also issues consumer advisories to alert consumers to certain practices that should be avoided, such as mixing radial and non-radial tires. However, we have never issued a consumer advisory on the use of passenger car radial tires on trailers, and we are not aware of any widespread hazard due to the use of such tires on trailers. Your State could have requirements for the use of tires on trailers. We suggest that you check with the California Highway Patrol for information on that issue. We regret we are unable to be more helpful. Should you have any further questions, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam0099OpenMr. Paul L. Nine, Manager, Product Regulations, Chrysler Corporation, Office of Civic Affairs, Detroit, MI 48231; Mr. Paul L. Nine Manager Product Regulations Chrysler Corporation Office of Civic Affairs Detroit MI 48231; Dear Mr. Nine: Thank you for your letter of August 9, 1968, containing literature o 'Super-Lite' which will be an optional lighting device on the 1969 Dodge Polara and Monaco Models.; According to the literature, 'Super-Lite' is an auxiliary o supplemental light to be used in conjunction with the low beams of the regular headlamps.; For many years, all lighting devices used on motor vehicles registere in New Jersey have been required to be approved by the New Jersey Division of Motor Vehicles. Lighting devices are added to our approved list after a sample has been submitted along with a report from an independent testing laboratory showing that the device meets the standards of the Society of Automotive Engineers. We will also add a motor vehicle lighting device to our approved list after we receive an Approval Certificate from the American Association of Motor Vehicle Administrators showing that the device meets the SAE Standards.; Electric Supplementary Lamps, such as the 'Super- Lite' are covered b SAE Standard No. J582. Perhaps you have submitted a sample light and the necessary test report to the AAMVA, but as yet, we have not received a copy of the Approval Certificate.; In case you desire to have us approve the 'Super- Lite' on the basis o New Jersey alone, please send us a sample and test report, as mentioned above.; Unless the 'Super-Lite' is on our approved list at the time moto vehicles equipped with the lighting device are going through our inspection stations, the vehicles will have to be rejected.; New Jersey R.S. 39:3-51 concerns the mounting and aiming of auxiliar driving lights. A copy of this section is enclosed for your information.; Very truly yours, John A. McLaine, Chief, Automotive Engineerin Standards; |
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ID: aiam1564OpenMr. P.K. Kamath, Oshkosh Truck Corporation, P.O. Box 2566, Oshkosh, WI 54901; Mr. P.K. Kamath Oshkosh Truck Corporation P.O. Box 2566 Oshkosh WI 54901; Dear Mr. Kamath: This responds to your July 2, 1974, question whether a truck complie with the dynamometer requirements of S5.4 of Standard No. 121, *Air brake systems*, if its brakes are actuated by smaller slack adjusters and brake chambers than those specified by the brake manufacturer to establish torque levels which comply with the standard. Your question arises under the interim requirements of S5.3.1.2 and the full requirements of S5.4.2 and S5.4.3 as they apply to the on/off-highway category.; Standard No. 121 is a vehicle requirement, and the NHTSA will conduc compliance testing for dynamometer requirements using the force levels applied to the brakes on the particular vehicle it is testing. This means that if you use 5.5-inch slack adjusters and 30-inch brake chambers on your truck, the NHTSA would use the force applied by these components in its compliance testing. There is no prohibition to your modifying the brake manufacturer's 'recommended package' to suit your needs. However, you should be able to show that, in the exercise of due care, the brake assembly meets the requirements of S5.4 as modified.; If you believe that the established dynamometer requirements conflic with optimum handling and stopping performance, you may, under NHTSA procedural rules (49 CFR 563, copy enclosed) petition to modify the standard.; In response to your July 10, 1974, letter asking whether a air-over-hydraulic front brake is subject to certain requirements of Standard No. 105a, I enclose a preamble to that standard which states that air-over-hydraulic systems are regulated only by Standard No. 121.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam5236OpenMr. Richard G. Meier Deputy Assistant Office of the U.S. Trade Representative 600 17th Street, N.W. Washington, DC 20506; Mr. Richard G. Meier Deputy Assistant Office of the U.S. Trade Representative 600 17th Street N.W. Washington DC 20506; Dear Mr. Meier: This letter follows up on the July 23, 1993, meeting i which you and Ms. Suzanne Troje discussed with representatives of this agency concerns of the Mexican Government that tires produced in Mexico for sale in the U.S. must be labeled in English and tested in Texas. We would like to explain our regulations and correct an apparent misimpression of the Mexican government. Tires manufactured for sale in the United States must be labeled with safety and consumer information that is required by statute (the National Traffic and Motor Vehicle Safety Act) and by regulation. The regulations require that the information be in English. There is no available exception to the English labeling requirement for the safety information, but there is an exception to the consumer information requirement of our uniform tire quality grading standards (UTQGS, copy enclosed). The UTQGS do not apply to 'limited production tires,' as defined in that standard. This exception could provide the basis for a Mexican tire manufacturer to import a limited number of tires into this country to assess the market. However, the annual importation of that tire into the U.S. must not exceed 15,000 tires. The UTQGS do not require that manufacturers test their tires at this agency's test track at San Angelo, Texas. Manufacturers may test their tires where they choose, and may even choose not to test their products at all. However, the specification in the UTQGS regulations that testing is done at San Angelo means that NHTSA must use that track in any compliance testing of tires. In order to protect themselves against the possibility that the agency will find a noncompliance based on testing at San Angelo and initiate an enforcement action, it would be prudent for tire manufacturers to base their assigned grades on their own testing at San Angelo or on some substitute means whose results demonstrably correlate with the results of testing at San Angelo. We hope this information is helpful. For your information, I have attached a general information sheet discussing NHTSA's requirements for new manufacturers. Please let us know if we can be of further assistance. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam4354OpenMr. Mark Roberts, 40 East Stillforest, Houston, Texas 77024; Mr. Mark Roberts 40 East Stillforest Houston Texas 77024; Dear Mr. Roberts: This is in reply to your letter of June 9, 1987, with respect to a aftermarket motorcycle lamp that you wish to produce. You refer to the lamp as a 'motorcycle safety light' that would supplement other motorcycle lighting and 'would be a rear facing or all direction light with an amber colored lens that would flash'. You have asked if there are any restrictions or guidelines for such a lamp.; Your letter does not indicate the size, flash rate, or intensity of th light, nor whether you intend it so be installed by motorcycle dealers prior to the first sale, or available only for installation on motorcycles already in use. However, I can give you some general guidelines.; Federal Motor Vehicle Safety Standard No. 108, *Lamp, Reflectiv Devices, and Associated Equipment* contains the requirements that apply to motorcycles and must be met at the time of sale and delivery to their first owner. Generally, except as provided in the standard (*e.g* motorcycle headlamp modulating devices) all lamps must be steady burning in use. Your lamp, however, would flash, and therefore appears precluded as an item of original equipment. Further, vehicle equipment must not impair the effectiveness of lighting equipment required by the standard. Although in the absence of specifications of your lamp we cannot say whether it would impair the effectiveness of required motorcycle lighting equipment, we note that an(sic) rearward facing amber flashing lamp could create confusion with a rearward facing amber turn signal lamp.; As an aftermarket device intended for vehicles in use, your lamp i subject only to the Federal restriction that its installation by a dealer, distributor, or motor vehicle repair business shall not render inoperative in whole or in part other required lighting equipment. Should your device place an excessive drain on a motorcycle battery affecting the operability of other lighting equipment it could be viewed as violative of the Federal restriction. However, even if this question is answered in the negative, the question of the acceptability of the supplemental lamp is determined by the laws of the State in which the device is sold or used. We are unable to advise you on these laws, and suggest that you write American Association of Motor Vehicle Administrators, 1301 Connecticut Ave., N.W., Washington, D.C. 20016, for further information.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam4733OpenMr. Suichi Watanabe General Manager Automotive Lighting Engineering Control Department Stanley Electric Co., Ltd. 2-9-13, Nakameguro, Meguro-ku Tokyo 153, Japan; Mr. Suichi Watanabe General Manager Automotive Lighting Engineering Control Department Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Watanabe: This is in reply to your letter of March 19, 1990 asking whether a new combination rear lamp is permitted under Motor Vehicle Safety Standard No. 108. The lamp consists of three compartments. In its normal operating mode, when the taillamp and/or stop lamp are activated, all three compartments show a red light. Your question arises with respect to three different operating modes. The first occurs when the turn signal is activated, the red light in one of the compartments is replaced by an amber flashing one. The second occurs when the backup lamp is activated, the red light in another of the compartments is replaced by a white steady-burning one. The third occurs when both the backup lamp and turn signal are activated, in this event, the combination lamp would present an amber flashing light, a red steady-burning one, and a white steady-burning one. You have informed us that 'the requirement of photometric and lighted area for each lamp function comply to FMVSS No. 108 and related SAE Standards.' Further, as for the stop and taillamp functions, they comply with requirements for one and three compartment lamps when operating with one or three compartments (we assume that they would also meet the requirements for two compartment lamps). The lamp appears to be intended to fulfill the requirements of Standard No. 108 for turn signal, stop, tail, and backup lamps. Thus, your question appears to be whether Standard No. 108 requires separate lamps or compartments dedicated to a specific purpose, or whether your multiple purpose lamp is acceptable. Standard No. 108 does not prohibit a combination of the functions that any chamber of your lamp provides. When a specific function is activated, the lamp will perform that particular function in a manner that appears to meet the minimum standard established by Standard No. 108. Assuming that the CIE color definitions for white, amber, and red are met by the backup, turn, and stop/tail functions, the lamp appears to be permissible under Standard No. 108. Sincerely, Stephen P. Wood Acting Chief Counsel; |
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ID: aiam3799OpenMr. Ben Barbie, Stapleton Public Schools, P.O. Box 125, Stapleton, NE 69163; Mr. Ben Barbie Stapleton Public Schools P.O. Box 125 Stapleton NE 69163; Dear Mr. Barbie: This is in further reply to your phone call of February 13, 1984, t the National Highway Traffic Safety Administration, regarding the remanufacture of school buses using older model bus bodies on new chassis. You asked whether the school bus safety standards apply to a school bus manufactured with a 1976 model year body mounted on a new chassis.; The applicability of Federal Motor Vehicle Safety Standards i determined by the date of manufacture of the motor vehicle. For vehicles that are completed in several stages, the manufacturer can treat as the date of manufacture the date of the incomplete vehicle, the date of final completion of the vehicle, or a date between those two dates. An 'incomplete vehicle' is defined in 49 CFR Part 568, *Vehicles Manufactured in Two or More Stages*, as:; >>>an assemblage consisting, as a minimum, of frame and chassi structure, power train, steering system, suspension system, and braking system, to the extent that those systems are to be part of the completed vehicle, that requires further manufacturing operations, other than the addition of readily attachable components, such as mirrors or tire and rim assemblies, or minor finishing operations such as painting, to become a completed vehicle.<<<; The effective date of the school bus safety standards was April 1 1977. Since the date of manufacture of the school bus chassis is after April 1, 1977, and the date of completion of the vehicle is after April 1, 1977, the completed school bus must meet the requirements of the school bus safety standards. It is extremely unlikely that the 1976 model year body will comply with the school bus standards since the body was manufactured before the effective date of the school bus standards. If your completed vehicle does not comply with the safety standards, your manufacturer, distributor, or dealer cannot certify it as conforming to such standards.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3800OpenMr. Ben Barbie, Stapleton Public Schools, P.O. Box 125, Stapleton, NE 69163; Mr. Ben Barbie Stapleton Public Schools P.O. Box 125 Stapleton NE 69163; Dear Mr. Barbie: This is in further reply to your phone call of February 13, 1984, t the National Highway Traffic Safety Administration, regarding the remanufacture of school buses using older model bus bodies on new chassis. You asked whether the school bus safety standards apply to a school bus manufactured with a 1976 model year body mounted on a new chassis.; The applicability of Federal Motor Vehicle Safety Standards i determined by the date of manufacture of the motor vehicle. For vehicles that are completed in several stages, the manufacturer can treat as the date of manufacture the date of the incomplete vehicle, the date of final completion of the vehicle, or a date between those two dates. An 'incomplete vehicle' is defined in 49 CFR Part 568, *Vehicles Manufactured in Two or More Stages*, as:; >>>an assemblage consisting, as a minimum, of frame and chassi structure, power train, steering system, suspension system, and braking system, to the extent that those systems are to be part of the completed vehicle, that requires further manufacturing operations, other than the addition of readily attachable components, such as mirrors or tire and rim assemblies, or minor finishing operations such as painting, to become a completed vehicle.<<<; The effective date of the school bus safety standards was April 1 1977. Since the date of manufacture of the school bus chassis is after April 1, 1977, and the date of completion of the vehicle is after April 1, 1977, the completed school bus must meet the requirements of the school bus safety standards. It is extremely unlikely that the 1976 model year body will comply with the school bus standards since the body was manufactured before the effective date of the school bus standards. If your completed vehicle does not comply with the safety standards, your manufacturer, distributor, or dealer cannot certify it as conforming to such standards.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5194OpenDr. Thomas L Luckemeyer Dept. VER/LB SWF Auto Electric GmH; Dr. Thomas L Luckemeyer Dept. VER/LB SWF Auto Electric GmH; "FAX 07142/73 28 95 Dear Dr. L ckemeyer: As you have requested, we ar responding by FAX to your FAX letter of June 25, 1993, to Taylor Vinson of this Office. Our FAX letter to you of May 28, 1993, provided an interpretation of SAE J588 NOV84, incorporated by reference in Federal Motor Vehicle Safety Standard No. 108. You mention the l990 SAE Ground Vehicle Lighting Manual which refers to SAE J588 September l970, and ask which is the correct SAE reference. Standard No. 108 was amended with an effective date of December 1, 1990, to substitute 'SAE J588 NOV84' for 'SAE J588 September 1970' as the U.S. Federal requirement for turn signal lamps used as original equipment on passenger cars and other motor vehicles with an overall width of less than 80 inches overall width. Turn signal lamps may still be manufactured to the requirements of 'SAE J588 September 1970' if they are intended to replace original equipment turn signal lamps that were manufactured in accordance with 'SAE J588 September 1970.' We understand that your earlier letter asked for an interpretation of Standard No. 108 as it related to the design of lamps for future production, and trust that this answers your question. As you have requested, we are also FAXing a copy of Table III. Sincerely, John Womack Acting 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.