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: aiam4706OpenMr. Thomas D. Turner Manager, Engineering Services Blue Bird Body Company P.O. Box 937 Fort Valley, GA 31030; Mr. Thomas D. Turner Manager Engineering Services Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; "Dear Mr. Turner: This responds to your letter seeking a interpretation of the meaning of the term 'front outboard designated seating position,' for the purposes of Standards No. 202, Head Restraints (49 CFR 571.202) and No. 208, Occupant Crash Protection (49 CFR 571.208). Specifically, you referred to a typical seating arrangement on a small bus your company manufactures. In this seating arrangement, the driver's seating position is located immediately to the rear of the left side of dashboard. There are no other seating positions in the same row as the driver's seat. Instead, a side entrance door and stepwell are to the right of the driver's seat with an unobstructed passage between the driver's seat and the entrance door. To the rear of the driver's seat, there are four rows of passenger seats on each side of the bus, separated by a center aisle that runs the length of the bus. You offered your opinion that the forwardmost passenger seating position on the right side of the bus, which is to the rear of the driver's seating position and the entrance door and stepwell, is not a front outboard seating position for the purposes of Standards No. 202 and 208. Your understanding is correct. While NHTSA has never specifically defined 'front' seating positions, the agency has used that term to refer to the driver's seating position and all other seating positions in the same transverse or lateral row as the driver's seating position. In the small bus described in your letter, the forwardmost passenger seat on the right side of the bus is not in the same transverse row as the driver's seat, it is to the rear of that row. Therefore, the forwardmost passenger seat on the right side of your bus would not be a 'front' seat for the purposes of Standards No. 202 or 208. Sincerely, Stephen P. Wood Acting Chief Counsel"; |
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ID: aiam1857OpenHonorable Vance Hartke, United States Senate, Washington, DC 20510; Honorable Vance Hartke United States Senate Washington DC 20510; Dear Senator Hartke: Thank you for your letter of March 7, 1975, asking for detaile consideration of Mr. David L. Daugherty's concern that final-stage manufacturers will be unable to fulfill their certification responsibilities on air-braked trucks built after March 1, 1975. As you know, Standard No. 121, *Air brake systems*, became effective for trucks and buses on March 1, 1975.; Mr. Daugherty has raised one of the most critical aspects of truc manufacturing in assuring a minimum brake performance level. Unlike passenger cars, the vast majority of heavy trucks are manufactured by adding specialized bodies or equipment to a chassis-cab. These additions affect the center of gravity, dynamic load transferral, and other characteristics of the truck which determine in large part its stopping capability.; As a practical matter, meaningful dynamic brake performance standard cannot be developed without regulating the truck as it is completed and sold.; The National Highway Traffic Safety Administration (NHTSA) recognize that Standard No. 121, as the first comprehensive performance requirement for trucks, will limit somewhat the freedom of manufacturers to modify brake systems and mount bodies without regard for their effect on braking. We consider the increased care exercised by final-stage manufacturers to be one of the most significant benefits of the standard.; Mr. Daugherty correctly points out that chassis-cab manufacturer released the necessary information on their chassis only a short time before March 1, 1975. The two trade associations for final-stage manufacturers petitioned for delay of the standard for this reason. After careful consideration of possible relief, NHTSA denied those petitions. It was concluded that every form of relief had obvious drawbacks and would not achieve the objective of final-stage manufacturers to receive 121-type chassis to use in re-engineering their body and equipment installations. It was concluded that if the standard for completed vehicles were suspended, chassis manufacturers would no longer have to provide incomplete vehicles with the necessary equipment and final-stage manufacturers would be unable to develop solutions for their engineering problems. Even if incomplete vehicles could be certified and completed vehicles could be exempt, serious danger would exist when modifications of the new systems were undertaken without consideration of the handling consequences.; I would like to point out that the March 1, 1975, effective date doe not require an instantaneous ('one day') change for final-stage manufacturers. Part 568 of our regulations (49 CFR Part 568) permits a final-stage manufacturer to use the date of completion of the chassis as the date of certification of the completed vehicle. This means that the chassis manufactured prior to March 1 may be completed at any later period without meeting Standard No. 121. It is not until final-stage manufacturers begin to receive the chassis which have just started to be produced that they will have to complete vehicles in conformity with the standard. They now have data on the new chassis, and thus have a period in which to make modifications. Several manufacturers have large inventories of pre-121 chassis and it should be several months before all trucks will be completed in conformity with Standard No. 121.; Thank you for your continuing interest in motor vehicle safety. Sincerely, James B. Gregory, Administrator |
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ID: aiam0745OpenMr. Stan Haransky, Associate Director, Truck Body and Equipment Association, Inc., 5530 Wisconsin Avenue, Suite 1120, Washington, DC 20015; Mr. Stan Haransky Associate Director Truck Body and Equipment Association Inc. 5530 Wisconsin Avenue Suite 1120 Washington DC 20015; Dear Mr. Haransky: This is in reply to your letter of May 30, 1972, forwarding to u correspondence you received from Mr. Calvin D. Kunkle of FMC Corporation. Mr. Kunkle's question, as explained in a telephone conversation we had with him on June 16, 1972, is whether building vehicles whose actual loaded weight exceeds the gross vehicle weight rating of the chassis violates Federal law. Mr. Kunkle stated that he believed certain manufacturers of fire-fighting vehicles were presently doing that.; If the loaded weight is clearly inconsistent with the definitions o GVWR and GAWR as specified in 49 CFR 571.3, the manufacturer will be in violation of the Certification regulations, (49 CFR Part 567) and may be subject to civil penalties. Also, if the loaded weight of the completed vehicle or the weight imposed on any of its axle systems exceeds the stated ratings, the vehicle might be found by NHTSA to contain a safety-related defect. In such a case, the manufacturer is required to mail notification of the defect to all the purchasers. In addressing whether such a safety defect exists, the NHTSA considers the situation as a whole, including such factors as the manufacturer's ratings, and the true capacity of the vehicle.; We advised Mr. Kunkle during our conversation that if he will furnis to NHTSA the names of companies he suspects are involved in this practice, we will take action to bring them into conformity with the requirements.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2778OpenMr. Greg Kreshel, Alloy Trailers, Inc., P.O. Box 19208, Spokane, WA 99219; Mr. Greg Kreshel Alloy Trailers Inc. P.O. Box 19208 Spokane WA 99219; Dear Mr. Kreshel: This responds to your February 10, 1978, question whether a trailer i considered newly manufactured under section 571.7(f) of NHTSA regulations if new materials are used except for four running gear assemblies that come from the front and rear of two wrecked trailers and are welded together to form the front and rear tandems of the reassembled full trailer.; It is our understanding that the axles, wheels, braking and suspensio components would be taken from the existing trailers, the identity of one of the existing trailers would be continued in the reassembled trailer, and the two existing trailers would be owned or leased by the user of the reassembled trailer. Assuming that this understanding of the facts is correct, the NHTSA would consider the reassembled trailer to be not newly manufactured under 49 CFR 571.7(f) for purposes of the Act, implementing regulations, and the safety standards.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5547OpenMr. Dietmar K. Haenchen Manager, Vehicle Regulations Volkswagen of America, Inc. 3800 Hamlin Road Auburn Hills, MI 48326; Mr. Dietmar K. Haenchen Manager Vehicle Regulations Volkswagen of America Inc. 3800 Hamlin Road Auburn Hills MI 48326; "Dear Mr. Haenchen: This responds to your request for an interpretatio of Standard No. 118, Power- operated window, partition, and roof panel systems. You asked whether the 'squeezing force limitation' of S5 applies only to the first attempt to close a power operated window, partition, or roof panel system (power-operated system) and not to immediately following attempts to close. You explained that an operator may initiate more than one closing attempt in order to assure the closing of the power operated system under adverse conditions such as low temperature or the presence of ice in the power operated system's track. As discussed below, the S5 squeezing force limitation applies to each closing attempt. By way of background information, Standard No. 118 requires that a power operated system, while closing, must comply with one of two alternative provisions. The first, S4, generally specifies requirements for situations where a person is expected to be in the immediate vicinity of the vehicle to supervise the closing. The second, S5, covers 'unsupervised' closings, i.e., automatic closings or closings where the person initiating the closing is further away from the vehicle. In the rulemaking establishing S5, NHTSA recognized that unsupervised closings increase the risk that persons, especially children, could be caught between a closing system and the frame. Therefore, to the extent that a power operated system permits unsupervised closings, the agency decided to require an automatic reversal mechanism that reverses the window direction upon its meeting an obstruction. More specifically, if an obstruction is between 4 and 200 mm from any part of the vehicle structure with which the closing system mates, S5 requires window reversal before a force of 100 Newtons is encountered. S5 does not specify different squeezing force limitation requirements for different closing attempts. Therefore, a power operated system must meet the same requirements for each closing attempt. We note that since the requirements of S5 address unsupervised closings, the same safety concerns about children being caught between a closing system and frame would be relevant to each closing attempt. I note that NHTSA decided not to apply the S5 squeezing force limitation requirement to unsupervised closings within the area between 4 mm and any part of the vehicle structure with which the closing system mates. The agency recognized that injury from system closure is not possible in this area, and that unnecessary automatic reversal could result from the system's misalignment or obstruction from ice. Thus, during unsupervised closing, if the system encounters an obstruction less than 4 mm from any part of the vehicle structure with which the closing system mates, the power operated system need not reverse. I hope that this information is helpful. If you have any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam2282OpenMr. W. G. Milby, Staff Engineer, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Staff Engineer Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This is in response to your April 14, 1976, letter concerning th meaning of the effective dates of Federal motor vehicle safety standards.; You are correct in your understanding that a vehicle's date of sale i irrelevant to a determination of which standards are applicable to it. 49 CFR S571.7(a), *Applicability*, specifies in relevant part:; >>>...each standard ...applies according to its terms to all moto vehicles or items of motor vehicle equipment the manufacture of which is completed on or after the effective date of the standard.<<<; For vehicles that you complete by mounting a body on a chassis, you ar permitted by 49 CFR S567.5(a)(7) to treat as the time that manufacture is 'completed' for the purposes of S571.7(a) any date no earlier than the manufacturing date of the incomplete vehicle and no later than the date of completion of final-stage manufacture, regardless of when the body or chassis was sold. Please note that you must be consistent in your choice of completion date, e.g., you may not choose one date to determine applicability of certain standards while choosing another date for other standards.; Sincerely, Frank A Berndt, Acting Chief Counsel |
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ID: aiam0315OpenMr. Warren M. Barnett, c/o Barnett Sales and Service, 3710 Oxford Boulevard, Maplewood, MO 63143; Mr. Warren M. Barnett c/o Barnett Sales and Service 3710 Oxford Boulevard Maplewood MO 63143; Dear Mr. Barnett: This is in reply to your letter of February 23, 1971, requesting advic on the acceptability of your regrooving pattern for regrooved tires.; Enclosed is a copy of the Rules and Regulations on regrooved an regroovable tires as it appears in the *Federal Register* published January 24, 1969, under Section 369.7(a)(3) Requirements, 'After regrooving, the new grooves generated into the tread material and any residual original molded tread groove which is at or below the new regrooved groove depth, shall have a minimum of 90 linear inches of tread edges per linear foot of tire circumference.'; There are no measurements on your drawings to assist us in determinin if your zig-zag grooves and the three circumferencial grooves measure 90 linear inches. Three *straight* circumferential grooves would only provide approximately 72 linear inches.; The use of lateral cuts should substantially increase the tread edg measurements, providing the lateral cuts are from shoulder to shoulder to allow unobstructed fluid escape passages as required in Section 369.7(a)(5); Thank you for your interest in tire safety. Francis Armstrong, Director, Office of Standards Enforcement, Moto Vehicle Programs; |
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ID: aiam2328OpenMr. Richard L. Rogers, President, Little Dude Trailer Company, Inc., P.O. Box 4513, Fort Worth, Texas 76106; Mr. Richard L. Rogers President Little Dude Trailer Company Inc. P.O. Box 4513 Fort Worth Texas 76106; Dear Mr. Rogers: This is in response to your March 26, 1976, letter concerning th certification label requirements in S5.3 of Federal Motor Vehicle Safety Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*.; You have pointed out that the example shown in S5.3 presents rim inflation, and maximum speed information after the Gross Vehicle Weight Ratings (GVWRs) as well as after the Gross Axle Weight Ratings (GAWRs). You have suggested that the text of S5.3 merely requires such information to appear after the GAWRs and urged such an interpretation. It appears that you have misunderstood the text.; In its present form, S5.3 requires each listed GVWR and GAWR to b followed by the information specified in paragraphs S5.3(a) through (d). Paragraph (a) is divided into subparagraphs (a)(1) and (a)(2) in order to specify different items to follow GVWR and GAWR, respectively. Paragraphs (b) through (d) (which specify rim, inflation, and maximum speed information) are not subdivided because the same items are intended to follow GVWR and GAWR.; Several petitions for reconsideration of the standard have requeste and amendment of S5.3 to eliminate the requirements that tire and rim information appear after the GVWR. Your suggestions on this matter, as well as the other suggestions in your letter, are being considered by the National Highway Traffic Safety Administration in the preparation of its response to those petitions.; Please note that the effective dates of several of the standard' requirements, including that of S5.3, were delayed in a Federal Register notice published on May 6, 1976 (41 FR 18659, Docket No. 71-19, Notice 4). A copy of that notice is enclosed for your convenience.; Yours truly, Stephen P. Wood, Assistant Chief Counsel |
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ID: aiam5117OpenMr. Allan Ferver Product Manager Waekon Industries, Inc. 100 South Walnut Street Kennett Square, PA 19348; Mr. Allan Ferver Product Manager Waekon Industries Inc. 100 South Walnut Street Kennett Square PA 19348; "Dear Mr. Ferver: This responds to your letter asking about how thi agency's regulations would apply to a product which you call the 'Universal Replacement Fuel Cap.' You explained that this product is designed to replace lost fuel caps until the proper replacement can be obtained. I am pleased to have this opportunity to explain our regulations to you. I am also enclosing a copy of a fact sheet entitled 'Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment.' By way of background information, NHTSA is authorized to issue Federal Motor Vehicle Safety Standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA is not authorized to certify or approve motor vehicles or motor vehicle equipment for compliance with the Federal Motor Vehicle Safety Standards. Instead, under the National Traffic and Motor Vehicle Safety Act, each manufacturer of a motor vehicle or item of motor vehicle equipment is responsible for certifying that its products meet all applicable safety standards. There is currently no Federal Motor Vehicle Safety Standard that is directly applicable to a replacement fuel cap. Nevertheless, you should be aware of Safety Standard No. 301, Fuel System Integrity, which may be relevant to your product. Standard No. 301 applies only to new motor vehicles and specifies performance requirements that must be met by the fuel system as a whole following crash tests. The standard does not apply to individual components of a fuel system or to aftermarket equipment for use on fuel systems. Although Standard No. 301 would not directly apply to a replacememt fuel cap, there are responsibilities under Federal law of which you should be aware. Manufacturers of motor vehicle equipment, which includes fuel caps, are subject to the requirements in sections 151-159 of the Safety Act concerning the recall and remedy of products with defects relating to motor vehicle safety. In addition, there are prohibitions against certain modifications of new and used vehicles. Section 108(a)(2)(A) of the Safety Act specifies that no manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative any device or element of design installed on or in a new or used motor vehicle in compliance with any applicable Federal Motor Vehicle Safety Standard. Therefore, no person in any of the aforementioned categories may place your fuel cap on a motor vehicle if by so doing the vehicle's compliance with Standard No. 301 were negatively affected. Whether your fuel cap could be installed on a vehicle by a person in one of those categories without taking the vehicle out of compliance with Standard No. 301 or any other applicable Federal safety standard is a determination that must be made by the entity making the installation. Please note that the prohibition of 108(a)(2)(A) does not apply to individual vehicle owners who alter their own vehicles. Thus, under Federal law, a vehicle owner may install or remove any item of motor vehicle equipment regardless of its effect on compliance with the Federal safety standards. However, the agency encourages vehicle owners not to remove or otherwise tamper with vehicle safety equipment if the modification would degrade the vehicle's safety. We suggest that you also contact the Environmental Protection Agency to see whether EPA has any type of emissions standard that might affect you as the manufacturer of a fuel cap. The general telephone number for EPA is (202) 382- 2090. 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, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam5402OpenMr. Blair Abraham Biomedical Manager Mersco Medical P.O. Box 5061 Sioux Falls, SD 57117; Mr. Blair Abraham Biomedical Manager Mersco Medical P.O. Box 5061 Sioux Falls SD 57117; "Dear Mr. Abraham: This responds to your letter requesting informatio about 'the steps to take to certify a vehicle for a higher weight rating than what is issued by the manufacturer.' I apologize for the delay in our response. As discussed in your letter and in a telephone conversation with Edward Glancy of my staff, your company owns a 1989 or 1990 Chevy van which it uses to deliver products. You indicate that the GVWR assigned to the vehicle is 5,600 pounds. You modified the suspension to enable the vehicle to handle an additional 1,000 pounds and 'would like to certify the vehicle for 6,600 pounds.' You asked us to send the information required for increasing the GVWR and also ask, if you cannot increase the GVWR, whether you are liable for noncompliance of a DOT regulation. By way of background information, under the National Traffic and Motor Vehicle Safety Act, the National Highway Traffic Safety Administration (NHTSA) issues safety standards for new motor vehicles and new motor vehicle equipment. Manufacturers are required to certify that their vehicles and equipment meet applicable safety standards. Under NHTSA's certification regulations, manufacturers must assign a GVWR to new vehicles. The term GVWR is defined in 49 CFR Part 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. NHTSA expects the GVWR to reflect a manufacturer's good- faith evaluation of the vehicle's size, weight, load carrying capacity, and intended use. NHTSA's regulation on GVWR only addresses the GVWR of new vehicles. This is because the agency's safety standards apply only to new motor vehicles and new motor vehicle equipment. There is a provision, 108(a)(2)(A), in the Vehicle Safety Act that prohibits manufacturers, distributors, dealers and motor vehicle repair businesses from knowingly rendering inoperative in whole or in part any device or element of design installed in accordance with a Federal motor vehicle safety standard. These parties would be subject to this provision if they were to modify your vehicle's suspension. However, the provision does not apply to individual owners modifying their own vehicles. Because we do not regulate how individuals modify their own vehicles (and thus do not prohibit you from modifying your vehicle's suspension), we are unable to advise you about the specific modifications that must be made to a vehicle for it to safely carry an additional 1,000 pounds. Among other things, however, you should carefully evaluate whether the vehicle's axles, brakes, tires, and frame can adequately handle the additional load. We suggest that you consult with the original vehicle manufacturer about this question. You may also wish to consult a local attorney concerning possible liability in the event your vehicle is involved in an accident. Also, the individual states have the authority to regulate used vehicles, and changes in the GVWR of used vehicles may be addressed by state law. State law may also address the operation of a vehicle loaded above GVWR. I hope this information is helpful. If you have any further questions about NHTSA's regulations, please feel free to contact Mr. Glancy at this address or by telephone at (202) 366-2992. 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.