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: aiam4871OpenEric G. Hoffman, Esq. Russell & Hoffman, Inc. 2000 NCNB Plaza 300 Convent Street San Antonio, Texas 78205-3793; Eric G. Hoffman Esq. Russell & Hoffman Inc. 2000 NCNB Plaza 300 Convent Street San Antonio Texas 78205-3793; "Dear Mr. Hoffman: This responds to your letter of March 26, 1991 addressed to Mr. Harry Thompson, asking about a private school's use of 'mini-vans which are designed to carry more than 10 passengers.' Your letter was referred to our office for reply. You stated that the school has become aware of the National Traffic and Motor Vehicle Safety Act (Safety Act) and is concerned whether the operation of the vans is in compliance with applicable regulations under the Act. You asked a number of questions related to that concern. I am pleased to have this opportunity to clarify the operation of Federal law as it applies to school buses. The National Highway Traffic Safety Administration (NHTSA) defines 'school bus' as a motor vehicle designed for carrying 11 or more persons, including a driver, and sold for transporting students to and from school or school-related events. Therefore, the vehicles refered to in your letter would be considered school buses under federal law. The National Highway Traffic Safety Administration (NHTSA) has issued Federal motor vehicle safety standards applicable to all new school buses. These standards impose obligations on the manufacturers and sellers of new motor vehicles, not upon the subsequent users of these vehicles. It is a violation of Federal law for any person to sell as a school bus any new vehicle that does not comply with all school bus safety standards. If your client believes that they have been sold noncomplying vehicles, and that the dealer knew of their intended use, the school should contact NHTSA's Office of Vehicle Safety Compliance, at the address given above, and inform them of the apparent violation of Federal law. Without violating any provision of Federal law, a school may use a vehicle to transport school children, even if the vehicle does not comply with Federal school bus regulations. This is so because the individual States have authority over the activities of a user of a school bus. Since the various questions you ask assume that the Safety Act regulates users of school buses, we are unable to provide specific answers to those questions. To determine whether the private school your firm represents may use noncomplying vans, you must look to state law. I must emphasize NHTSA's position that a vehicle meeting Federal school bus regulations is the safest way to transport students. I encourage the school your firm represents to give its most careful consideration to the possible consequences of transporting students in vehicles that do not comply with these regulations. I hope you find this information helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam3925OpenMr. Jeffrey Richard, JBR Manufacturing, P.O. Box 415, Fairfield, IA 52556; Mr. Jeffrey Richard JBR Manufacturing P.O. Box 415 Fairfield IA 52556; Dear Mr. Richard: This responds to your letter inquiring about the Federal safet standards that would apply to a product you are planning to sell. You stated that the product is a 6 inch by a 4 inch sheet of 1/8 inch thick semi-transparent rubber that is held on a side window of a vehicle by four suction cups. The purpose of the sheet is to shield vehicle occupants from the sun. The following discussion explains the applicability of our safety standards to your sun screen.; Pursuant to the National Traffic and Motor Vehicle Safety Act, we hav issued Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials,* (49 CFR 571.205) which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70% in areas requisite for driving visibility, which includes all windows in passenger cars).; Any manufacturer, dealer or other person who installs tinting films o other sun screen devices, such as those described in your letter, in *new* vehicles must certify that the vehicle as altered, continues to comply with the requirements of the standard. Thus, for example, the light transmittance through the combination of the sun-screening material and the glazing must be at least 70 percent in the case of glazing used in windows requisite for driving visibility. Similarly, the combination must also meet the other applicable requirements of the standard, such as the abrasion resistance requirements.; After a vehicle is sold to the consumer, owners may alter thei vehicles as they please, so long as they adhere to all State requirements. Under Federal law, an owner may install any device regardless of whether the installation adversely affects light transmittance. The agency does, however, urge owners not to install equipment which would render inoperative the compliance of a vehicle with our standards. Individual States govern the operational use of vehicles by their owners and therefore it is within the authority of the States to preclude owners from applying sun screens on their vehicles.; If a manufacturer, dealer, distributor or motor vehicle repair busines installs the sun screen device for the owner of a used vehicle, then S108(a)(2)(A) of the Vehicle Safety Act may apply. That section provides that none of those persons may 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 a Federal motor vehicle safety standard. Violation of the 'render inoperative' provision can result in Federal civil penalties of up to $1,000 for each violation.; I am enclosing the sample of your product you sent with your letter. I you need further information, the agency will be glad to provide it.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam3975OpenMr. K. Weight, 65 E. 200 N., Provo, UT 84601; Mr. K. Weight 65 E. 200 N. Provo UT 84601; Dear Mr. Weight: Thank you for your letter to Secretary Dole concerning black windows i automobiles. Your letter was referred to the National Highway Traffic Safety Administration since we are the agency that issues Federal Motor Vehicle Safety Standards (FMVSS). We have issued FMVSS No. 205, *Glazing Materials*, which sets performance requirements, including light transmittance requirements, for glazing used in motor vehicles. As explained below, FMVSS No. 205 limits the use of darkly tinted windows.; FMVSS No. 205 requires glazing, both tinted and untinted, in a ne passenger car to transmit at least 70 percent of the light that falls on it. To give you an idea of what level of tinting is allowed, please consider the following examples. If a window were completely open, the light transmitted through the opening would be 100 percent, clear windows have about 90 percent light transmittance, while factory-equipped tinted windows in new vehicles have about 80 percent light transmittance.; Minimum visibility levels are necessary to allow the average driver t detect other vehicles, pedestrians, bicyclists and traffic and road signs under all lighting conditions. Were the light transmittance *less* than 70 percent, such as found in darkly tinted glazing, visibility would be reduced to the extent that it could pose a safety hazard. From your description, I assume that the light transmittance of the 'black window' is less than 70 percent. A situation where the light transmittance is below 70 percent may be in violation of FMVSS No. 205.; No manufacturer or dealer is permitted to install tinting material i new vehicles without certifying that the vehicle continues to be in compliance with the light transmittance requirements of the standard. If a dealer, manufacturer, repair business or distributor installs dark tinting material in a used vehicle, then a violation of Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act may result. That section provides that none of these persons may 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 motor vehicle safety standard. Violation of the 'render inoperative' provision can result in Federal civil penalties of up to $1,000 for each violation.; Owners of used vehicles may, themselves, alter their vehicles, so lon as the vehicle adheres to all State requirements. Under Federal law, the owner may in this manner install dark tinting material regardless of whether the installation adversely affects the light transmittance. Individual States govern the operational use of vehicles by their owners and therefore it is within the authority of the States to preclude owners from applying dark tinting material on their vehicles.; I hope this information is helpful to you. Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam2283OpenMr. 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 responds to Blue Bird Body Company's March 29 and 31, 1976, an April 14, 1976, requests for confirmation of several interpretations you have made regarding the new safety standards for school buses and the definition of 'school bus' as they become effective in October 1976.; Your interpretation is correct that 'bus passenger compartment' as use in S5.2.3.1 of Standard No. 217, *Bus Window Retention and Release*, means that portion of the bus that is rearward of the forwardmost point on the windshield.; You request confirmation that the requirement in S5.7(a) of Standar No. 220, *School Bus Rollover Protection*, to open emergency exits during the application of force to the bus roof are inappropriate and therefore not applicable in the case of roof exits. Your interpretation is correct, and the NHTSA intends to modify the language of Standard No. 220 appropriately.; You request confirmation that the knee impact requirement of S5.3.2. of Standard No. 222, *School Bus Passenger Seating and Crash Protection*, does not apply to the rear row of seating in a school bus because there is no passenger seating behind this row. Your interpretation is correct. I would like to point out that the seat back of the rear row of seating also is not subject to the requirements of S5.3.1.1 for the same reason. Your are also correct that 'school bus passenger seat' as defined in S4 does not include a wheelchair that is placed in a school bus to transport non- ambulatory bus passengers. Our response on other issues concerning special arrangements for handicapped passengers will be forthcoming as a response to the outstanding Sheller-Globe petition for reconsideration of Standard No. 222.; In your March 31, 1976, letter you asked whether a bus that is sold fo purposes that include carrying kindergarten and nursery school children to and from school or related events would be considered a school bus under the redefinition of 'school bus' that becomes effective October 27, 1976 (40 FR 60033, December 31, 1975). The answer to your question is yes, because the statutory definition underlying the NHTSA definition of school bus specifically lists preprimary students as passengers of school buses. See 15 U.S.C. S 1391(14).; In your April 14, 1976, letter you ask whether the requirement o S5.3.1.3 of Standard No. 222 for a minimum 'contact area' on a described spherical head form refers to the area of actual contact on the surface of the spherical head form, or the area of contact on the head form as seen in projected view. The 'contact area' refers to the area of actual contact on the surface of the head form.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2518OpenMr. Jack Gromer, Vice President - Engineering, 5990 N. Washington Street, Denver, Colorado 80216; Mr. Jack Gromer Vice President - Engineering 5990 N. Washington Street Denver Colorado 80216; Dear Mr. Gromer: This responds to Timpte's January 11, 1977, question whether NHTS regulations prohibit sale and delivery of a trailer to the first purchaser equipped with two used tires in place of the eight tires that are specified for the vehicle and which would form the basis of certification under Part 567, *Certification* and the basis of compliance with Standard No. 120, *Tire Selection and Rims for Vehicles Other Than Passenger Cars*.; As you are aware, Part 567 of our regulations requires a statement b the vehicle manufacturer of the gross axle weight rating (GAWR) for each axle on any motor vehicle it manufacturers (S567.4(g) (4)). The term 'GAWR' is defined in S571.3 of our regulations as the value specified by the manufacturer as the load-carrying capacity of the axle system, measured at the tire-ground interfaces. This clearly means that the tires and wheels on an axle must be taken into account in assigning a GAWR value for certification purposes.; Standard No. 120 specifies that 'each vehicle...shall be equipped wit tires that meet [specified requirements]' (S5.1.1) but makes provision for the installation of used tires owned by the purchaser if the maximum load ratings of the tires on an axle system are at least equal to the GAWR assigned to the axle system by the vehicle manufacturer (S5.1.3). Section S5.1.3 reflects the agency's view that existing commercial practices for delivery of vehicles with safe used tires has not created a significant safety problem to date.; In recognition of varying commercial practices for the delivery o vehicles, the agency has interpreted S5.1.1 of Standard No. 120 to prohibit the installation of tires that do not meet certain performance requirements, but not as a requirements that the tires be fitted to every axle of a vehicle prior to certification and sale. A copy of this interpretation is enclosed for your information. The interpretation makes clear that, while the agency interprets Standard No. 120 (and by implication Part 567) to permit the assignment of a GAWR on the basis of tires listed on the certification plate, the assignment of an arbitrarily high (or low) GAWR for purposes such a avoiding a Federal motor vehicle safety standard could constitute a violation of law.; With regard to the practice you describe of delivering an empty ne trailer to the purchaser on fewer tires than necessary to confirm to the GAWR listed on the certification plate and the minimum requirements of S5.1.1 and S5.1.2 of Standard No. 120, the agency interprets its motor vehicle safety standard and S567.4(g) (4) to permit such a good faith delivery practice. In the event any pattern of avoidance of Federal requirements becomes apparent, however, the agency would reconsider this interpretation.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam3955OpenMr. L. D. Pitts, Jr., P. O. Box 52592, Houston, TX 77002; Mr. L. D. Pitts Jr. P. O. Box 52592 Houston TX 77002; Dear Mr. Pitts: Thank you for your letter of March 12, 1985, asking about the effect o our regulations on a product you would like to manufacture. I hope the following discussion explains that effect.; You described your product, which you call a glare- shield, as 1/8-inch thick sheet of 'Lexan' plastic with a special scratch resistant coating. Your product is designed to be mounted inside a motor vehicle, as close to the windshield as possible, to reduce glare-related vision problems caused by the sun. You stated that your product would cover the entire windshield and is designed to be held in place by three or six latches. The latches can be released by the driver and the shield can be removed from the car.; Pursuant to the National Traffic and Motor Vehicle Safety Act, we hav issued Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials,* (49 CFR 571.205) which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70% in areas requisite for driving visibility, which includes all windows in passenger cars).; Any manufacturer, dealer or other person who installs tinting films o other sun screen devices, such as the one described in your letter, in *new* vehicles must certify that the vehicle as altered continues to comply with the requirements of the standard. Thus, for example, the light transmittance through the combination of the sun-screening material and the glazing must be at least 70 percent in the case of glazing used in windows requisite for driving visibility. Similarly, the combination must also meet the other applicable requirements of the standard, such as the abrasion resistance requirements.; After a vehicle is sold to the consumer, owners may themselves alte their vehicles as they please, so long as they adhere to all State requirements. Under Federal law, an owner may install any device regardless of whether the installation adversely affects light transmittance. The agency does, however, urge owners not to install equipment which would render inoperative the compliance of a vehicle with our standards. Individual States govern the operational use of vehicles by their owners and therefore it is within the authority of the States to preclude owners from using sun screens on their vehicles.; If a manufacturer, dealer, distributor or motor vehicle repair busines installs the sun screen device for the owner of a used vehicle, then S108(a)(2)(A) of the Vehicle Safety Act may apply. That section provides that none of those persons may 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 a Federal motor vehicle safety standard. Violation of the 'render inoperative' provision can result in Federal civil penalties of up to $1,000 for each violation.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam3191OpenMr. John B. White, Engineering Manager, Technical Information Department, Michelin Tire Corporation, One Marcus Avenue, Lake Success, New York 11042; Mr. John B. White Engineering Manager Technical Information Department Michelin Tire Corporation One Marcus Avenue Lake Success New York 11042; Dear Mr. White: This responds to your November 16, 1979, letter in which you requeste an interpretation of the requirements of Federal Motor Vehicle Safety Standard No. 109 (49 CFR S571.109). Specifically, you asked if it is permissible for a tire manufacturer to label its tires with information about other tire sizes which the labeled tire could be used to replace. For example, you stated that Michelin would like to label its tires with the alphanumeric tire size which its P-metric tire sizes could replace and that Michelin would like to label its 230-15 tires as replacements for the 225-15 tires. Such labeling is expressly prohibited by Standard No. 109.; Paragraph S4.3(a) of Standard No. 109 specifies that each tire shall b labeled with '*one* size designation, except that equivalent inch and metric size designations may be used.' With respect to the alphanumeric sizes and the P-metric replacements and the 225-15 and 230-15 sizes, the suggested replacements sizes have different section widths and minimum size factors than the sizes they would be replacing. In other words, they are not equivalent size designations, and S4.3(a) prohibits the tire from containing more than one size designation in these circumstances.; Labeling of the sort you have requested has been commonly referred t as 'dual-size markings.' Dual-size markings are a representation that a particular tire can be considered as meeting fully the criteria of two separate tire size designations. In fact, such tires do not satisfy the physical dimension criteria in Standard No. 109 for both size designations. As a consequence, labeling of this type was specifically prohibited when the labeling requirements o Standard No. 109 were amended at 36 FR 1195, January 26, 1971. The prohibition has been repeated in subsequent notices which addressed the question of tire labeling under the Standard, *see* 39 FR 10162, March 18, 1974 and 42 FR 12869, March 7, 1977.; I should note that prohibition of dual-size markings does not mean tha NHTSA believes that the replacement tires would perform inadequately if installed on the rims. However, dual-size markings represent a marketing effort by tire manufacturers to attempt to persuade consumers to change the size and/or type of tires mounted on their cars. It is inappropriate to extend this marketing effort to the Federally required label on the tire. The manufacturer must provide the consumer, in a straightforward manner, technical information necessary for the safety of the consumer's automobile. This should be the only purpose of the label.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4394OpenMr. William R. Pape, Jr., 8152 Ladoga Drive, Jacksonville, FL 32217; Mr. William R. Pape Jr. 8152 Ladoga Drive Jacksonville FL 32217; Dear Mr. Pape: This is in reply to your letter of August 22, 1987, to Taylor Vinson o this office, enclosing a copy of your letter to George Walton of AAMVA. In that letter you have asked three questions with reference to the center highmounted stop lamp required by Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*, to which you have asked that we reply.; Your first question is 'May one word be introduced on the brake light? Standard No. 108 prohibits combining the center highmounted stop lamp with any other lamp, or with any reflective device. It does not prohibit the addition of one or more words to the lens. However, there are basic requirements that the lamp must meet, and the word or words must not prevent the lamp from meeting them. Specifically, the effective projected luminous area of the lens must not be less than 4 1/2 square inches, and the lamp must meet specified candela maxima and minima at 13 discrete test points.; Your second area of interest is the color red. You have asked whethe it is a Federal requirement for all brake lamps, whether other colors may be substituted, and whether the color red may be adjusted to a lighter hue. Standard No. 108 requires all stop lamps to be red in color. This color is defined in SAE Standard J578c *Color Specification for Electric Signal Lighting Devices*, February 1977, expressing chromaticity coordinates according to the CIE (1931) standard colorimetric system. Red is rather narrowly defined, and falls with the y coordinates, 0.33 (yellow boundary) and 0.98 (purple boundary). Red is not acceptable if its is less saturated (paler), yellower, or bluer than the limit standards. Thus red could not be adjusted beyond the prescribed limits. In our opinion, the 'soft pink' or 'hot pink' that you believe is desirable would be beyond those limits. No color other than red is permitted for stop lamps.; Your final area of interest is whether one should consider marketing lamp with the features you have indicated, and whether there are 'hidden directives which would restrict or prohibit such marketing.' Under assumption that your lamp would not comply with the color requirements of Standard No. 108, we must advise you that a noncomplying lamp could not be sold as original equipment for passenger cars, or as a replacement for center high mounted stop lamps on passenger cars manufactured on or after September 1, 1985. Federal law would not prohibit its sale for use on vehicles other than these, but the lamp would be subject to the laws of any State in which it would be sold and used.; I hope that this answers your questions. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: nht93-4.42OpenDATE: June 23, 1993 FROM: Gail Lindsey -- Hillsborough County Public Schools, Risk Management & Safety Department, Tampa, Florida TO: Ron Engles -- Safety Counter Measure Division TITLE: None ATTACHMT: Attached to letter dated 8/5/93 (est) from John Womack (signature by Kenneth N. Weinstein) to Gail Lindsey (A41; Part 571.3) TEXT: This correspondence is a reply to our recent phone conversation concerning the transporting of school children to and from special events in any vehicle other than school buses. In the past, it has been School Board policy to disallow the use of mini-vans on such events. I am requesting any information on the crash safety standards of such vehicles, or any recommendations that your office may give so that we can make a safe and fair determination on this current policy. Any assistance you can give will be greatly appreciated. |
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ID: nht68-2.3OpenDATE: 06/27/68 FROM: AUTHOR UNAVAILABLE; David A. Fay; NHTSA TO: Department of Education TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of June 4, 1968, to Mr. George C. Nield, concerning the State Board of Education's requirement for school bus warning signal lamps. The warning signal system as described in your letter does not meet the requirements of Federal Motor Vehicle Safety Standard No. 108, effective January 1, 1969. A copy of this Standard is enclosed for your reference. A minimum of four red signal lamps is required and they shall be designed to conform to SAE Standard J887, July, 1964, a copy of which is also enclosed. Four additional amber lamps are permitted. The red and amber system and the red only system shall be installed in accordance with paragraph S3.1.3.2 and S3.1.3.3, respectively, of Standard No. 108. |
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.