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: aiam5050OpenMr. David H. Milligan 7287 S. 300 E. Midvale, UT 84047; Mr. David H. Milligan 7287 S. 300 E. Midvale UT 84047; "Dear Mr. Milligan: This responds to your letter asking about th Federal requirements that apply to the 'Car Seat Support,' an item you manufacture for use with infant restraints. Background Your device appears to consist of a fabric covered block of foam approximately 18x4x3 inches in size. The marketing material you sent shows that your device is intended to be placed under the bottom rearmost edge of an installed rear- facing infant seat (bottom rearmost edge relative to the vehicle). The device would cause the restraint to tip more toward the front of the car. We understand that the device is intended for use with vehicles that have seat cushions that slant downward toward the seat back, such as in some small cars. Infant restraints are tested by NHTSA for compliance with Federal Motor Vehicle Safety Standard (FMVSS) No. 213, Child Restraint Systems, on an approximately horizontal vehicle seat cushion. (The 'standard seat assembly' used to test the restraints is specified in S7.3 of Standard No. 213, copy enclosed.) A downward-slanting vehicle seat cushion might cause an infant restraint to tip toward the rear of the car. This could result in the angle between an infant restraint's back support surface and the vertical to decrease, i.e., the back of the restraint might become more upright. If a restraint's back support surface becomes too upright, it might not be able to provide support to the infant's head and neck. The purpose of your product is to prop the bottom of a rear-facing infant restraint when the restraint is used with a downward-slanting vehicle seat, to ensure that the restraint bottom is horizontal. You state that consumers currently use items such as 'blocks of wood' and 'rolled up towels' to serve the same purpose as the Car Seat Support. NHTSA's Response There is currently no FMVSS that directly applies to the product you wish to manufacture and sell. FMVSS No. 213 applies only to new child restraint systems and not to aftermarket supporting devices. However, there are other Federal laws that indirectly affect your manufacture and sale of the device. Under the National Traffic and Motor Vehicle Safety Act, your product is considered to be an item of motor vehicle equipment. As a manufacturer of motor vehicle equipment, you are subject to the requirements in sections 151-159 of the Safety Act concerning the recall and remedy of products with safety related defects. I have enclosed an information sheet that briefly describes those responsibilities. In the event that you or NHTSA determines that your device contain a safety- related defect, you would be responsible for notifying purchasers of the defective equipment and remedying the problem free of charge. In addition, manufacturers, distributors, dealers, and motor vehicle repair businesses are subject to 108(a)(2)(A) of the Safety Act, which states: 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative ... any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard ....' It appears unlikely from the nature of your product that it would be placed in vehicles by commercial businesses instead of child restraint owners. However, if your product were to be installed by persons in those categories, they should ensure that its installation does not compromise the safety protection provided by a child restraint system. The prohibition of 108(a)(2)(A) does not apply to the actions of vehicle owners in adding to or otherwise modifying their vehicles or items of motor vehicle equipment. Please note that we are concerned that your device might compromise the safety protection provided by an infant seat if the consumer is not provided clear information about the use of the product. The Car Seat Support you provided came with a label that has a picture of the device positioned under a rear- facing infant seat. There is no other instruction on the label on the use of the product. In the absence of clear instructions, there is the potential that consumers might misuse the Car Seat Support. For example, a consumer might not know that the restraint is intended for use with only a rear-facing restraint that needs a 'support' to keep the bottom of the restraint horizontal when positioned on a vehicle seat. Without proper instructions, a consumer might use the Car Seat Support on an approximately horizontal vehicle seat cushion and thereby inappropriately tilt the restraint so that it does not provide sufficient crash protection. One means of reducing the likelihood of confusion about the proper use of the product would be for you to provide consumer instructions on the use of the Car Seat Support, such as on the purpose of the product, on the type of restraint and vehicle seat for which the device is intended, and on limiting how far rearward the restraint should be permitted to tilt. The picture of the Child Seat Support in use should be consistent with those instructions. I hope this information is helpful. If you have further questions, please contact Deirdre Fujita of my staff at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosures"; |
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ID: aiam2795OpenMr. Robert W. Shebar, 38 N. Main Street, Freeport, NY 11520; Mr. Robert W. Shebar 38 N. Main Street Freeport NY 11520; Dear Mr. Shebar: This responds to your letter to Joan Claybrook on March 23, 1978, whic urges an extension of the exemption presently granted to TVR Cars of America, Ltd., from compliance with Standard No. 215, *Exterior Protection*. As noted in our earlier letter to TVR, Standard No. 215 was issued under the authority of one statute, the National Traffic and Motor Vehicle Safety Act, while the upcoming Part 581 *Bumper Standard* is issued under authority of this statute and a second one, the Motor Vehicle Information and Cost Savings Act (the Cost Savings Act).; Our earlier letter pointed out that the Cost Savings Act does no contain exemption authority which is as broad as that contained in the National Traffic and Motor Vehicle Safety Act. In the case of Part 581, the Department of Transportaiton (sic) can only exempt a passenger motor vehicle 'manufactured for a special use if (the) standard would unreasonably interfere with the special use of such vehicle' (15 U.S.C. S1912(c)(1)(B)). The legislative history of this provision cites a 4- wheel-drive vehicle equipped with a snow plow attachment as an example of a special use that would be unreasonably interfered with by a bumper standard.; Upon careful consideration of the issues raised in your letter, we d not believe there is an available basis for extension of TVR'd (sic) present exemption beyond the September 1, 1978, effective date of Part 581. The particular financial and engineering circumstances of TVR do not bear upon the limited grounds for exemption contained in the Cost Savings Act.; Thank you for bringing this matter to our attention. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3887OpenMr. Rod L. Stafford, Fryford Corporation, 2nd Seat, 982 North Batavia, Unit B-12, Orange, CA 92667; Mr. Rod L. Stafford Fryford Corporation 2nd Seat 982 North Batavia Unit B-12 Orange CA 92667; Dear Mr. Stafford: This responds to your recent letter requesting information on which o the agency's regulations would apply to a new product you are considering. You described the product as a 'hammock-like seat which, unrolled and fastened into the rear bed of any pickup truck, forms a comfortable passenger seat which may be easily stowed inside the truck cab.' You stated that you plan to sell your product as an item of aftermarket equipment and asked about the application of our regulations to your product.; If your product is sold as an item of aftermarket equipment to b installed by a vehicle owner, it would not be required to comply with Standards Nos. 207, 208, 209, 210, and 302. We were pleased to learn that you have nevertheless voluntarily designed your product to conform to those standards.; As a manufacturer of an item of motor vehicle equipment, you do have responsibility under section 151 *et* *seq*. of the National Traffic and Motor Vehicle Safety Act to conduct a notification and remedy campaign if you or the agency determines that your product contains a safety-related defect or does not comply with an applicable standard. A copy of the Act is enclosed.; If you have any further questions, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0252OpenMr. Lawrence R. Walders, Tanaka and Walders, Federal Bar Building West, 1819 H Street, N.W., Washington, D.C. 2006; Mr. Lawrence R. Walders Tanaka and Walders Federal Bar Building West 1819 H Street N.W. Washington D.C. 2006; Dear Mr. Walders: This will acknowledge your letter of July 27, 1970 to the Nationa Highway Safety Bureau requesting an interpretation of Federal Motor Vehicle Safety Standard No. 110.; You are correct in your statement that no formal petition for rul making action is necessary for tire and rim combination cited within the references of S3 of Standard No. 109.; Concerning your question on 'approval equivalent rim', we offer th following. The policy of the Bureau in 1967 at the time of the promulgation of Standard No. 109 and No. 110 was to give a 'blanket' approval of all rims cited within the references. From that time on however, all *new* tire and rim combinations had to be approved by the Bureau. After the tire and rim combination was approved then it was listed within Table I, Appendix A of Standard No. 110.; Standards No. 109 and No. 110 do not have requirements for ri contours. Our standards only specify the flange letter-code and width for a particular rim resignation. Therefore, any request to change a rim dimension of an existing rim does not require a formal action by this Bureau.; Sincerely, Lawrence R. Schneider, Acting Deputy Chief Counsel |
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ID: aiam0747OpenMr. Robert T. Sanders, Vice President, Manufacturing--Window Division, 4801 Springfield Street, Dayton, OH 45401; Mr. Robert T. Sanders Vice President Manufacturing--Window Division 4801 Springfield Street Dayton OH 45401; Dear Mr. Sanders: This is in reply to your letter of June 1, 1972, requesting a interpretation as to the application of Federal Motor Vehicle Safety Standard No. 205, 'Glazing Materials,' to certain recreational vehicles and equipment, pictures of which you enclosed. These components consist of slide-in and chassis-mount campers, trailers, and motor homes.; In a recently issued amendment to Standard No. 205, the NHTSA ha clarified the application of the standard to campers. As amended, the standard applies to campers, both slide-in and chassis-mount, that are designed to transport occupants while in motion. Accordingly, the pick-up cap which you illustrate appears to be exempt from the standard. In addition Standard No. 205 does not apply to trailers, and would not apply to the fifth-wheel unit illustrated in the drawing forwarded to us.; With reference to the chassis-mount and slide-in campers, any windo except forward facing windows, which include both front-facing windows and behind-the-cab windows, may be manufactured of any glazing material (AS 1 through AS 11) specified in ANS Z26.1-1966, and two additional materials (Items 12 and 13), the requirements for which are specified in the recent amendment. With reference to forward-facing camper windows, all of the above materials may be used, except for AS 6 and AS 7 glazing materials, as specified in ANS Z26.1-1966, and item 13 glazing specified in the new amendment.; With respect to motor homes that are not campers, these vehicles ar multipurpose passenger vehicles and must meet the glazing requirements for trucks. Accordingly, the windshield must be manufactured of either AS 1 or AS 10 glazing materials, side windows to the immediate right or left of the driver must be either AS 1, AS 2, AS 10, or AS 11 materials, and other side windows must be either AS 1, AS 2, AS 3, AS 4, AS 5, AS 8, AS 9, AS 10, or AS 11 glazing materials. We would consider the overhead window in the motor home you illustrate to be an 'opening in the roof,' and any of the materials allowed in side windows, or the materials allowed to be used by the recent amendment, may be used in this location.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1855OpenMr. Emanuel Laster, 8th Floor Mears Building, Scranton, PA; Mr. Emanuel Laster 8th Floor Mears Building Scranton PA; Dear Mr. Laster: This responds to your March 19, 1975, question whether Standard No 121, *Air brake systems*, applies to an air-braked trailer which has a primary cargo-carrying surface that is 23 inches above the ground in the unloaded condition and has a rack-type structure which may be added to the trailer to permit carrying several boats.; I have enclosed an amendment of Standard No. 121 which excludes certai trailers from its requirements until September 1, 1976. From your description of the sides as easily removable, and from the enclosed illustration, it appears that the trailer in question qualifies as a heavy hauler trailer and would not be required to conform to Standard No. 121 until September 1, 1976.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3868OpenMr. Le Olin Chamberlain, 226 N. Williamson Road, Blossburg, PA 16912; Mr. Le Olin Chamberlain 226 N. Williamson Road Blossburg PA 16912; Dear Mr. Chamberlain: This responds to your letter to the National Highway Traffic Safet Administration (NHTSA) which concerned the Federal Motor Vehicle Safety Standards relating to school bus safety. You asked whether a school bus contractor is automatically exempt from the Federal school bus safety standards if that contractor is a Public Utilities Commission (PUC) certificate carrier. The answer is no.; Under the National Traffic and Motor Vehicle Safety Act of 196 (hereinafter 'the Vehicle Safety Act'), our agency has the authority to issue safety standards applicable to new motor vehicles. In 1974, Congress amended the Vehicle Safety Act to direct NHTSA to issue standards on specific aspects of school bus safety. A new 'bus' (i.e., a motor vehicle designed for carrying 11 persons or more) which is sold for purposes that include carrying students to and from school or school-related events is a 'school bus' under our regulatory definition. A manufacturer or dealer who sells a new bus who know that the vehicle will be significantly used as a school bus must ensure that the vehicle complies with the Federal school bus safety standards.; You stated in your letter that a school bus contractor has notifie your school district that 'under his PUC rights he is exempt from Federal Safety Regulations.' For the reasons discussed below, such a statement is inaccurate. Buses purchased by a PUC certificate carrier are not per se exempt from the Federal school bus safety standards.; It is correct that the regulatory definition of 'school bus' issued b this agency under the Vehicle Safety Act excludes a bus 'designed and sold for operation as a common carrier in urban transportation.' (49 CFR 571.3) However, the exclusion does not give persons who sell new buses to common carrier operators the license to disregard the school bus safety standards when they sell the buses. This is because the applicability of the standards to a bus is determined by its intended use, not by the fact that the purchaser has common carrier operations or holds a PUC certificate. Whether a particular bus must comply with the school bus safety standards depends on the intended use of that bus, as determined at the point of the vehicle's sale. If the seller of the school bus knows that the vehicle will be significantly used by the PUC carrier as a school bus, he must sell a bus that complies with the Federal school bus standards or be subject to substantial penalties under the Vehicle Safety Act.; Please contact this office if you have further questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2280OpenMs. Constance Newman, Assistant Secretary for Consumer Affairs and Regulatory Functions, Department of Housing and Urban Development, 451 Seventh Street, S.W., Washington, D.C. 20410; Ms. Constance Newman Assistant Secretary for Consumer Affairs and Regulatory Functions Department of Housing and Urban Development 451 Seventh Street S.W. Washington D.C. 20410; Dear Ms. Newman: I am writing in response to questions that have been raised about th National Highway Traffic Safety Administration's (NHTSA) authority to regulate mobile homes. As you may know, mobil homes have been considered to be 'motor vehicles' as that term is defined in the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1391 et seq.) ('the Vehicle Safety Act'). As such, they have been subject to Federal Motor Vehicle Safety Standard No. 108 (*Lamps, Reflective Devices, and Associated Equipment) and to our authority regarding the notification and remedy of noncompliances and defects related to motor vehicle safety.; The National Mobile Home Construction and Safety Standard Act of 197 (42 U.S.C. 5401 et seq.) ('the Mobile Home Act') established within the Department of Housing and Urban Development a comprehensive program for the regulation of mobil homes. We have concluded that one result of that statute's enactment was the implied repeal of the NHTSA's authority with respect to mobile homes. Accordingly, we consider that the enactment had the effect of amending the Vehicles Safety Act's definition of 'motor vehicle' to exclude 'mobile homes' as the latter term is defined in the Mobile Home Act. We are preparing a Federal Register notice that will reflect this conclusion.; Sincerely, James B. Gregory, Administrator |
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ID: aiam5545OpenMr. Stephen M. Padula Industry Standards and Government Regulations Uniroyal Goodrich Tire Company P.O. Box 2501 Greenville, SC 29602; Mr. Stephen M. Padula Industry Standards and Government Regulations Uniroyal Goodrich Tire Company P.O. Box 2501 Greenville SC 29602; "Dear Mr. Padula: This responds to your letter of March 21, 1995, i which you asked whether it is permissible to have a treadwear grade of 00 or 000 on tires under the Uniform Tire Quality Grading Standards (UTQGS), 49 CFR 575.104. The answer to your question is yes. As you know, the UTQGS currently provide that all new passenger car tires sold in the United States must be graded by their manufacturers or brand name owners for treadwear, traction, and temperature resistance. The grades must be assessed in accordance with paragraphs (d)(1)(i)(A) and (B) of the UTQGS and must be molded into or onto the tire sidewall. Paragraph (d)(2)(i) requires the treadwear grade to be expressed as 2 or 3 digits, representing the percentage (P) of the NHTSA nominal treadwear value, computed as follows: Projected P = mileage x 100 30,000 The percentage derived from the above formula is then rounded off to the nearest lower 20-point increment to arrive at the treadwear grade. In your letter you proposed a hypothetical example of a tire with a projected mileage of 5,000 miles, which would compute as follows: P = 5,000 x 100 = 16.67 30,000 Rounded off to the nearest lower 20-point increment, the treadwear rating for that tire would be 00 or 000. Your example would be correct, if tires still exist that have a projected tread life of 5,000 miles. Although NHTSA has not found any tires so rated, under the current provisions of the UTQGS, it is possible, as demonstrated by your example, to have a UTQGS treadwear rating of 00 or 000. I hope this information is helpful to you. Should you have any questions or need additional information, 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: aiam0317OpenMr. Keitaro Nakajima, General Manager, Toyota Motor Company, Ltd., Lyndhurst Office Park, 1099 Wall Street West, Lyndhurst, New Jersey 07071; Mr. Keitaro Nakajima General Manager Toyota Motor Company Ltd. Lyndhurst Office Park 1099 Wall Street West Lyndhurst New Jersey 07071; Dear Mr. Nakajima: #This is to confirm your understanding that the DO symbol, which represents the tire manufacturer's certification that the tire complies with the passenger car tire standard, is required on tires installed on multipurpose passenger vehicles, if such tires are originally designed and have passenger car tire size designations. However, since Standard No. 110 does not, at the present time, apply to multipurpose passenger vehicles,the responsibility for assuring that these tires contain the DOT symbol is limited to the tire manufacturer. #Sincerely, Lawrence R. Schneider, 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.