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: aiam0350OpenMr. Lawrence Petterson, Hicks Oil Company, 215 1/2 East Main Street, Pipestone, MN 56164; Mr. Lawrence Petterson Hicks Oil Company 215 1/2 East Main Street Pipestone MN 56164; Dear Mr. Petterson: This is in reply to your letter of April 28, 1971. Under Part 574, th tire identification number may be placed on the side of the top cap area or may be branded into the tire in accordance with the regulation. If the top cap area is used, the number should be as close to the sidewall as is feasible so that the number will remain legible as long as possible. See the enclosed amendment on this subject (Docket No. 70-12, Notice No. 9).; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam2443OpenMr. George R. Semark, Manager, Vehicle Safety Activities, Sheller-Globe Corporation, Vehicle Planning and Development Center, 3555 St. Johns Avenue, Lima, OH 45804; Mr. George R. Semark Manager Vehicle Safety Activities Sheller-Globe Corporation Vehicle Planning and Development Center 3555 St. Johns Avenue Lima OH 45804; Dear Mr. Semark: This responds to Sheller-Globe Corporation's August 31, 1976, questio whether 5 described intersections in a bus body qualify as 'body panel joints' subject to the requirements of Standard No. 221, *School Bus Body Joint Strength*.; The windshield fence that you describe in section A of your lette connects the window glazing seal to the bus body and is considered to be a portion of the window by the NHTSA. Windows are excluded from the definition of 'body panel joint' found in S4 of the standard. Therefore, the fence would be excluded from the requirements of the standard.; The 'trim molding' described in section B of your letter constitutes body panel that encloses occupant space. The fact that the trim is decorative does not place it within the exclusion of 'spaces designed for ventilation or other functional purpose.' Since the 'trim molding' is a body panel and is connected to a body component, it creates a joint subject to the requirements of the standard. The fact that the molding, like every other part of the bus, has a function does not exclude it from the ambit of the joint requirement under the exception for 'ventilation or other functional purpose.'; In section C of your letter, you acknowledge that the joint where th skirt panel connects to the outside upper body panel falls within the ambit of the standard. You request an exception from the standard's requirements for this joint based upon a perceived lack of safety hazards resulting from failure of this joint in a crash situation.; To implement the Congressional mandate for school bus safety, the NHTS drafted Standard No. 221 to cover all joints that are potentially dangerous in a crash situation. The agency adopted this broad coverage of joints to avoid the more piecemeal approach of analyzing each joint for possible safety problems, because it is impracticable to test every joint in every possible accident configuration. Therefore, since the joint you describe falls within the parameters of the standard, it must meet the requirements specified.; The joint described in section D of your letter where the vent eve connect to the outside roof panel is a joint within the definition of the standard. The outside roof panel is a 'body panel' as defined in S4. The junction where a 'body panel' connects to a 'body component,' the vent eves, constitutes a joint regulated by the standard.; With regard to section E of your letter, the NHTSA agrees that th joint where the outside and inside lower panels connect is within the scope of the standard. Whether or not the joint itself is covered by trim molding is not relevant to its status. It is still a joint within the definition of the standard and subject to all of the requirements therein.; I trust these interpretations fully answer your questions. Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam5386OpenMr. and Mrs. Hal Sullivan 33891 Calle Borrego San Juan Capistrano, CA 92675; Mr. and Mrs. Hal Sullivan 33891 Calle Borrego San Juan Capistrano CA 92675; "Dear Mr. and Mrs. Sullivan: This responds to your letter to Davi Elias, formerly of this office, requesting an interpretation of the term 'rated cargo load' used in 49 CFR 567.5. I apologize for the delay in responding. You state in your letter that you purchased a 1992 Pace Arrow motor home from Fleetwood Motor Homes of California, Inc. You state that, if this motor home is equipped with 'the identical factory optional HWH hydraulic jacks,' it will exceed its gross vehicle weight rating (GVWR) when the available water tanks are filled to capacity. You characterize this as 'seriously inadequate carrying capacity,' and ask if this violates NHTSA's regulations. As explained below, if a vehicle exceeds its GVWR when loaded with its intended cargo, the manufacturer may be subject to civil penalties. By way of background, 114 of the National Traffic and Motor Vehicle Safety Act requires each motor vehicle manufacturer to certify the compliance of its new vehicles with all applicable Federal motor vehicle safety standards. NHTSA issued its vehicle certification regulation (49 CFR Part 567) to implement 114. Section 108(a)(1)(E) of the Safety Act prohibits any person from failing to comply with any regulation issued under 114. Under 109 of the Safety Act, violations of 108(a)(1)(E) are subject to a civil penalty of up to $1,000 for each violation. NHTSA's certification regulation specifies the content of the certification label, and requires manufacturers to assign a GVWR to its new vehicles. The term GVWR is defined in 49 CFR 571.3 as 'the value specified by the manufacturer as the loaded weight of a single vehicle.' The GVWR informs vehicle owners how heavily the vehicle may safely be loaded. It also affects the vehicle's loading and other test conditions for the performance tests to ascertain whether the vehicle complies with applicable safety standards. The only express regulatory limitation on the GVWR that manufacturers may assign to their vehicles is set forth in 49 CFR 567.4(g)(3), which provides that the assigned GVWR 'shall not be less than the sum of the unloaded vehicle weight, rated cargo load, and 150 pounds times the vehicle's designated seating capacity.' (Emphasis added.) There is no express definition for the term 'rated cargo load' in Part 567 or elsewhere in NHTSA's regulations. However, NHTSA expects the GVWR (which includes rated cargo load) to reflect a manufacturer's good-faith evaluation of the vehicle's size, weight, load-carrying capacity and intended use. NHTSA is concerned about the potentially adverse effects on safety that might result from assigning too low a GVWR to a vehicle. NHTSA recognizes that vehicle overloading may create a serious safety problem and will take appropriate action against any manufacturer whose vehicle, when operated in its intended manner, exceeds the assigned GVWR. Thank you for bringing this matter about the Pace Arrow to our attention. NHTSA's Office of Vehicle Safety Compliance will be contacting you for more information about your experience with the vehicle. Meanwhile, if you have further questions, please contact Deirdre Fujita of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0184OpenMr. Erich K. Dorfner, Product Development Manager, Thompson Aircraft Tire Corporation, 160 Beacon Street, South San Francisco, California 94131; Mr. Erich K. Dorfner Product Development Manager Thompson Aircraft Tire Corporation 160 Beacon Street South San Francisco California 94131; Dear Mr. Dorfner: In response to your letter of November 6, 1969, the Department o Transportation hereby assigns number *211* to the Thompson Aircraft Tire Corporation, South San Francisco, California, as its approved code mark. The approved code mark is for use in identifying the tire manufacturer in accordance with S4.3 of the Federal Motor Vehicle Safety Standard No. 109 and the National Traffic and Motor Vehicle Act of !966 (15 USC 1421(1)).; You are cautioned that the approved code mark at the present time i for use only on new pneumatic passenger car tires.; Sincerely, Roger H. Compton, Director, Office of Standards on Acciden Avoidance, Motor Vehicle Safety Performance Service; |
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ID: aiam2013OpenMr. John H. Mueller, The Weatherhead Company, 300 East 131st Street, Cleveland, Ohio 44108; Mr. John H. Mueller The Weatherhead Company 300 East 131st Street Cleveland Ohio 44108; Dear Mr. Mueller: #Please forgive the delay in responding to you letter of March 25,1975, which suggested an inconsistency in the labeling requirements of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*. #S5.1 of the standard requires each hydraulic brake hose assembly to be equipped with end fittings which are attached by means of crimping or swaging. You have correctly pointed out that S5.2.3 specifies labeling requirements for 'hydraulic' end fittings which are neither crimped nor swaged, even though at present there are no hydraulic fittings, that fit that description. This language appears as part of S5.2 because S5.2 is incorporated by reference in S7.2 and S9.1, the labeling requirements for hose, fittings, and assemblies used in air and vacuum brake systems, respectively. Although there is thus no inconsistency, the National Highway Traffic Safety Administration is considering a clarifying amendment along the lines you have suggested, which would eliminate S5.2.3 and specify the labeling requirements directly in S7.2 and S9.1. #Thank you for pointing out this potential source of confusion. #Sincerely, Frank A. Berndt, Acting Chief Counsel; |
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ID: aiam4597OpenThe Honorable Leon E. Panetta House of Representatives Washington, DC 20515; The Honorable Leon E. Panetta House of Representatives Washington DC 20515; "Dear Mr. Panetta: This letter responds to your inquiry on behalf o your constituent, Mr. Botelho. You asked whether Federal regulations require mirrors to be placed on the right side of vehicles and whether such mirrors must be convex in nature. Mr. Botelho expressed his objection to requiring convex mirrors, because he believes convex mirrors distort images and cause objects to appear further away than they actually are. I am pleased to have this opportunity to explain this requirement and its background for you. Standard No. 111, Rearview Mirrors (49 CFR /571.111, copy enclosed)) establishes performance and location requirements for the rearview mirrors installed in new vehicles. Specifically, a passenger car whose inside rearview mirror does not meet the field of view requirements of section S5.1.1 must have an outside mirror on the passenger side of either unit magnification or a convex mirror. In a September 2, 1982 final rule amending Standard No. 111, the National Highway Traffic Safety Administration (NHTSA) explained that convex mirrors offer safety benefits by providing an expanded field of view to the rear, thereby reducing the need for the driver to turn around to view the rear directly. On the other hand, some users of convex mirrors that were used to the images shown by conventional plane mirrors incorrectly perceived that the object shown in the convex mirror was further to the rear than it actually was. Additionally, some users of convex mirrors experienced double vision, eyestrain, and nausea. After considering these potential advantages and disadvantages, NHTSA amended Standard No. 111 so that it does not require any vehicle to be equipped with convex mirrors, but it permits the use of convex mirrors on the passenger side of cars and light trucks, provided that the convex mirror meets certain additional requirements. The additional requirements applicable to convex mirrors on the passenger side of cars and light trucks are: 1. A maximum radius of curvature for the convex mirror. This limits the range of convexities to which drivers will be exposed. It also ensures that the field of view will be noticeably greater than for a plane mirror. 2. A minimum radius of curvature for the convex mirror. This ensures that the image size in the convex mirror will be adequate and distortion will not be excessive. 3. A stringent maximum permissible variation in the radius of curvature over the surface of the convex mirror. This requirement, which is more stringent than the European requirement in this area, also ensures that convex mirrors will have low distortion. 4. A warning etched on the convex mirror that objects shown in the mirror are closer than they appear. This requirement ensures that the driver who may not be familiar with convex mirrors will not be misled by the image size of the convex mirror and the apparent distance to the object. Hence, we agree with Mr. Botelho that the areas he has identified are potential problems unique to convex mirrors. However, our standard includes special requirements for convex mirrors to minimize the potential problems identified by Mr. Botelho and other potential problems that were identified in research studies of convex mirrors. We are not aware of any data showing that convex mirrors that comply with those special requirements present any unacceptable problems for drivers. I hope this information is helpful. If you have any further questions or need any additional information on this subject, please let me know. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam3252OpenMr. Mark Wood, MPI, Inc., P.O. Box EE, Coldwater, MS, 38618; Mr. Mark Wood MPI Inc. P.O. Box EE Coldwater MS 38618; Dear Mr. Wood: This confirms your April 9, 1980, telephone conversation with Roge Tilton of my staff in which you asked whether a styrofoam board that lies beneath a layer of polyurethane foam would be required to comply with the flammability requirements of Standard No. 302, *Flammability of Interior Materials*.; As Mr. Tilton explained to you, the standard applies to seatin components such as yours only to the extent that they fall within 1/2 inch of the occupant compartment air space. This requirement is specified in paragraph S4.2 of the standard. You indicate that your styrofoam board would not fall within 1/2 inch of the compartment because the polyurethane cover will always be thicker than 1/2 inch. Assuming this is true, your styrofoam board would not be required to comply with the standard.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1795OpenMr. William H. Toller, Manager Customer Service, MacDermid Incorporated, 526 Huntingdon Avenue, Waterbury, CT 06720; Mr. William H. Toller Manager Customer Service MacDermid Incorporated 526 Huntingdon Avenue Waterbury CT 06720; Dear Mr. Toller: This is in response to your letter of January 22, 1975, commenting o the recent proposal by the National Highway Traffic Safety Administration (NHTSA) to reduce the performance requirements for motor vehicle bumpers.; Under current Federal requirements, a vehicle bumper must be capable o withstanding 5-mph longitudinal front and rear barrier and pendulum impacts without experiencing certain types of specified damage. A recent NHTSA study, however, indicated that due to inflation, increasing shortages of certain materials, and the weight and cost of current production bumpers, the costs imposed by implementation of the bumper standard may be exceeding the benefits to be derived therefrom.; The proposed reduction in the requirements to 2 1/2 mph front and rea barrier and pendulum impacts was viewed as a means of attaining a favorable cost-benefit ratio by permitting the removal of certain heavy bumper system components. Considerable interest has been manifested in the contents of the proposal. The NHTSA conducted a public hearing on February 18 and 19, 1975, in order to permit the presentation of views from all interested persons regarding the proposed revision of the bumper standard.; The comment period for the notice has been extended until March 3 1975, in order to allow additional time for submission of comments and enable a full review of all evidence presented.; The comments contained in your letter will be placed in the appropriat public docket and will be considered in the formulation of the final rule.; Yours truly, James C. Schultz, Acting Chief Counsel |
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ID: aiam0887OpenMr. Kenneth D. Uding, Sales Promotion, Stimsonite Division, Amerace-Esna Corp., 3445 North Kimball Avenue, Chicago, Illinois 60618; Mr. Kenneth D. Uding Sales Promotion Stimsonite Division Amerace-Esna Corp. 3445 North Kimball Avenue Chicago Illinois 60618; Dear Mr. Uding: This is in response to your request for an interpretation of Standar 125, Warning Devices, with respect to the required marking of the date of manufacture on the device. I apologize for the delay in answering your letter. You inquire whether a circular marking in which the last numeral of the year of manufacture is printed inside an inner circle and the month of manufacture is represented by 'small dots' in an outer circle meets the requirements of S5.1.4.; S5.1.4 requires the device to be 'permanently and legibly marked wit ... month and year of manufacture, which may be expressed numerically, as '6/72' ...' The intent of this provision is not only to 'identify subquality batches' to the manufacturer or enforcement personnel, but also to provide the consumer with a clear indication of the date of manufacture in case of a possible defect or failure to meet safety standards. The method of marking the date of manufacture which you propose would not satisfy the language or intent of the requirement, since its meaning would not be clear to the average consumer.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3602OpenThe Honorable Bob McEwen, House of Representatives, Washington, DC 20515; The Honorable Bob McEwen House of Representatives Washington DC 20515; Dear Mr. McEwen: This responds to your July 8, 1982, letter to Mr. William Dabaghi o the Department enclosing correspondence from your constituent Mr. Donald M. Robinson. Mr. Robinson would like to know whether Federal regulations prohibit him from purchasing a pickup cab and chassis without the body attached. The answer to his question is no.; The National Highway Traffic Safety Administration only requires tha all vehicles be manufactured in compliance with the applicable motor vehicle safety standards. We have no requirement, nor do we know of any other Federal regulation, that would prevent Mr. Robinson from purchasing just the cab and chassis of a vehicle that he desires. When he adds his own utility body to the cab and chassis, he would become the final-stage vehicle manufacturer and would be required to certify that the completed vehicle complies with all applicable Federal safety standards. I am enclosing copies of the regulations pertinent to such an operation.; If I can be of further assistance to you or Mr. Robinson, pleas contact me.; Sincerely, Diane K. Steed, Administrator |
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.