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: 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; |
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ID: aiam5115OpenThe Honorable Paul David Wellstone United States Senate 2550 University Avenue, West Court International Building St. Paul, MN 55114-1025; The Honorable Paul David Wellstone United States Senate 2550 University Avenue West Court International Building St. Paul MN 55114-1025; Dear Senator Wellstone: Thank you for your letter on behalf of you constituents, Ms. Tutti Sherlock and Ms. Mary Bock, regarding the application of the National Highway Traffic Safety Administration's (NHTSA's) school bus standards to Head Start facilities. Your constituents ask that NHTSA inform the Minnesota Department of Transportation that we do not require school bus manufacturers to provide school bus equipment, such as stop arms and special stop lights, on Head Start buses. They base this request on their belief that in 1985, NHTSA said that states may decide which regulations should apply to Head Start buses. They also believe that stop arms and lights for Head Start buses are unnecessary, and that painting Head Start buses yellow could be confusing. We cannot provide the requested interpretation, because the understanding of your constituents is incorrect. By way of background, your constituents' concerns relate to two sets of regulations, issued under different Acts of Congress. The first of these, the Federal motor vehicle safety standards (FMVSS's) issued under the National Traffic and Motor Vehicle Safety Act ('Safety Act'), apply to the manufacture and sale of new motor vehicles. NHTSA has issued a number of FMVSS's for school buses, including FMVSS's requiring these buses to have a stop arm and warning lights. The Safety Act requires that each person selling a new bus (defined in our regulations as a vehicle designed for 11 or more persons) to a primary, preprimary or secondary school must sell a bus that is certified to the FMVSS's for school buses. State law cannot change this requirement. The question of whether Head Start facilities are 'schools' under the Safety Act has been addressed by NHTSA since the beginning of the school bus FMVSS's. The agency's longstanding position is that Head Start programs are primarily educational in focus rather than custodial, and are therefore 'schools' under the Safety Act. We base this conclusion on a review of the goals and functions of the Head Start program (see, e.g., 45 CFR 1304.1-3), and on past NHTSA interpretations of 'school.' NHTSA has stated its position that Head Start facilities are schools most recently in an August 21, 1992 letter to Mr. Chuck Anderson of the Minnesota Department of Transportation. Any new bus that is sold to a Head Start facility must have the safety features of a school bus at the time of the vehicle's sale, including the stop arm and signal lights. However, the Safety Act does not require Head Start facilities to use school buses or any other particular vehicle, nor does it require school buses to be painted yellow. The maintenance and operational characteristics of school buses are matters left to the individual states. NHTSA's second set of school bus regulations, issued under the Highway Safety Act, is a set of recommendations to the states for developing effective pupil transportation programs. Highway Safety Program Guideline No. 17, 'Pupil Transportation Safety' (copy enclosed), recommends that any vehicle designed for 11 or more persons that is used as a school bus should comply with the FMVSS's for school buses and should be painted yellow. However, Guideline 17 would affect the operation of your constituents' school buses only to the extent that Minnesota has incorporated it into state law. I hope this information will be helpful in responding to your constituents. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam3852OpenMr. H. Nakaya, Branch Manager, Mazda (North America), Inc., 23777 Greenfield Road, Suite 462, Southfield, MI 48075; Mr. H. Nakaya Branch Manager Mazda (North America) Inc. 23777 Greenfield Road Suite 462 Southfield MI 48075; Dear Mr. Nakaya: This responds to your letter dated January 20, 1984, concerning Federa Motor Vehicle Safety Standard (FMVSS) No. 101, *Controls and Displays*. You asked whether the standard would allow 'a secondary, redundant control placed in the rear seat area facilitating operation of the heating/ventilation and audio system functions by rear seat passengers.' As explained below, the answer to your question is yes.; By way of background information, the National Highway Traffic Safet Administration (NHTSA) does not pass approval on the compliance of any vehicle or equipment with a safety standard before the actual events that underlie certification. Under the Vehicle Safety Act, it is your responsibility as a manufacturer to determine whether your vehicles and equipment comply with all applicable safety standards and regulations, and to certify your products in accordance with that determination. The following interpretation only represents the agency's opinion based on the information provided in your letter.; Your letter indicates that controls for the heating and ventilatio unit would be placed in the rear seating area. You stated that these controls would be 'redundant' and 'secondary.' NHTSA assumes that there will be additional controls for the various functions of the units that are operable by and visible to the driver of the vehicle which meet all applicable requirements of Standard No. 101.; Section 5.2.1 requires identifications of any hand-operated contro listed in column 1 of Table 1 of that section to be visible to the driver. Listed in column 1 are 'Heating and/or Air Conditioning Fan,' and 'Heating and Air Conditioning System.'; You asked about illumination requirements in section 5.3 of FMVSS No 101 that might apply. Again, this section is intended to regulate the controls and displays operable by and visible to the driver, not the controls located in the rear seating area.; In requiring properly located and effectively identified controls an displays under FMVSS No. 101, the agency sought to reduce the safety hazards caused by the diversion of the driver's attention from the road. Locating secondary controls for passengers in the rear seating area for the heating and ventilation system would not distract the driver from the operation of the motor vehicle. The identification and illumination requirements of sections 5.2 and 5.3 were intended to apply only to the controls operable by and visible to the driver.; You should be aware, however, that section 5.3.3 of FMVSS No. 10 provides that '(t)he intensity of any illumination that is provided in the passenger compartment when and only when the headlights are activated shall also be variable in a manner that complies with this paragraph.' This section applies to all illumination in the passenger compartment that is dependent on activation of the headlights regardless of whether it shines upon a control display, to enable drivers to reduce the glare in the passenger compartment. Items such as radios and clocks which are not regulated by the location and identification requirements of FMVSS No. 101 are subject to the variable intensity requirements of section 5.3.3 if illuminated when, and only when, the headlights are activated. If the controls located in the rear seating area that operate the heating and ventilation unit are illuminated in this way, the standard requires that the light intensity for such controls must be continuously variable as described in section 5.3.3. You should further note that where you provide a control for the illumination intensity, section 5.1 of FMVSS No. 101 requires that it be operable by the driver, and its identification visible to the driver. We interpret this section to require at least one such control to be operable by and its identification visible to the driver. If a manufacturer separately meets the requirement of S5.1 by a properly located and identified control, additional controls that are added voluntarily by the manufacturer are not prohibited.; You indicated in your letter that Mazda is considering placin secondary controls for the audio system in the rear seating area. Controls and displays for audio systems are not regulated by FMVSS No. 101. The location and identification of these controls and displays are left to the discretion of the manufacturer. Once again, however, if the controls are illuminated when, and only when, the headlights are activated, then the same analysis discussed above applies. At least one control for the illumination intensity must be operable by the driver, with its identification visible to the driver.; In conclusion, FMVSS No. 101 does not prohibit placing the secondar controls for the heating and ventilation unit and audio system in the rear seating area. We would like to point out that there are other safety standards which may apply to your proposal that you should consider when you design these features for your automobiles, such as FMVSS No. 201, *Occupant Protection in Interior Impact*.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2740OpenMr. K. A. Dirkzwager, Driver and Vehicle Services Director, Minnesota Department of Public Safety, Transportation Building, St. Paul, MN 55155; Mr. K. A. Dirkzwager Driver and Vehicle Services Director Minnesota Department of Public Safety Transportation Building St. Paul MN 55155; Dear Mr. Dirkzwager: This is in response to your letter of November 15, 1977, requesting a exemption from the Federal odometer disclosure regulations which will become effective as of January 1, 1978.; We appreciate the efforts of Minnesota to include odometer informatio on its certificates of title. However, we are not granting any exemptions for States which have not previously had odometer information on their titles. Since the citizens of your State have had to execute separate odometer disclosure statements in the past they will not be placed under any additional burden by this ruling. They will merely continue past practices until such time as Minnesota incorporates the revised odometer format on their titles.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam5085OpenMr. Ron Noirfalise Director of Pupil Transportation Missouri Department of Elementary and Secondary Education Post Office Box 480 Jefferson City, MO 65102-0480; Mr. Ron Noirfalise Director of Pupil Transportation Missouri Department of Elementary and Secondary Education Post Office Box 480 Jefferson City MO 65102-0480; "Dear Mr. Noirfalise: This follows up your telephone conversation o November 10, 1992, with Walter Myers of my staff regarding a newly-effective statute in Missouri which revises state requirements on transportation of school children. You also stated that you were told by your counterpart in the State of Washington that Federal law prohibits transportation of school children in vehicles with a passenger capacity of less than ten people. As discussed in your telephone conversation with Mr. Myers, I have enclosed four recent letters explaining Federal law and pertinent regulations applicable to school buses and transportation of school children. These four are a November 3, 1992 letter to Mr. G. Thomas Owens, a July 7, 1992 letter to Senator Jim Sasser, a May 27, 1992 letter to Mr. Gerald A. Guertain, and a January 15, 1991 letter to Ms. Carol C. Verenea. These letters cover a variety of issues that, I think, will clarify your understanding of the issues with which you are concerned. Also enclosed is a copy of a pamphlet issued by this agency entitled Federal Motor Vehicle Safety Standards and Regulations, revised June 1989, and an information sheet issued by this agency entitled Where to Obtain NHTSA's Safety Standards and Regulations. In addition, I am enclosing for your information a copy of Highway Safety Program Guideline No. 17, Pupil Transportation Safety. This publication was issued under the authority of the Highway Safety Act of 1966 which authorizes this agency to issue nonbinding guidelines that states may refer to in developing their highway safety programs. Guideline 17 was jointly issued by this agency and the Federal Highway Administration to provide recommendations to the states on various operational aspects of their school bus and pupil transportation safety programs. Among other things, Guideline 17 recommends that any vehicle designed to carry more than ten persons which is used as a school bus comply with all safety standards applicable to school buses at the time the vehicle was manufactured. I hope the enclosed information will be of assistance to you. If you have any further questions, feel free to contact Mr. Myers at this address or at (202) 366-1992. Sincerely, Paul Jackson Rice Chief Counsel Enclosures"; |
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ID: aiam0287OpenMr. P.H.G. Morgan, Managing Director, Morgan Motor Company, Ltd., Pickersleigh Road, Malvern Link, Worchestershire, England; Mr. P.H.G. Morgan Managing Director Morgan Motor Company Ltd. Pickersleigh Road Malvern Link Worchestershire England; Dear Mr. Morgan: By letter of November 19, 1970, you petitioned for reconsideration o Federal Motor Vehicle Safety Standard No. 214 - Side Door Strength (35 F.R. 16801, October 30, 1970). After consideration of the issues raised by Morgan's petition, the National Highway Traffic Safety Administration has found no sufficient justification for amending the standard and the petition is therefore denied.; Your company's petition states that the standard presents difficultie for cutaway doors, and that the structure of Morgan automobiles supplies a measure of protection through flared side fenders that extend beneath the doors. The Administration recognizes that there is considerable variety in door and side structure. However, the need to protect occupants of all vehicles from injury in side collisions dictates a uniform measure of such protection, and the Administration has determined that the requirements of Standard No. 214 are reasonable, practicable and appropriate for passenger cars.; The remaining points in your letter of November 19, 1970, are mor nearly questions for interpretation than requests for reconsideration. Your second question pertains to the height (or length) of the loading device. The standard states only that the device must not contact any structure above the bottom edge of the door window opening. There is no other restriction on the maximum height of the test device, and it is not clear, without further explanation, why Morgan would be limited to a cylinder only 4 inches high.; Your remaining question deals with the positioning of side windows Although the standard specifies that side windows shall be in the uppermost position, it does not require that side windows exist and should not be so interpreted.; Sincerely, Douglas W. Toms, Acting Administrator |
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ID: aiam2310OpenMr. T. Takeda, Manager, Automotive Lighting Engineering Dept., Stanley Electric Co., Ltd., 2-9-13, Nakameguro, Meguro-Ku, Tokyo 153, Japan; Mr. T. Takeda Manager Automotive Lighting Engineering Dept. Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-Ku Tokyo 153 Japan; Dear Mr. Takeda: This is in reply to your letter of April 20, 1976, asking for a amendment of S4.1.1.21 of Motor Vehicle Safety Standard No. 108 to allow a plus tolerance of 7.5 percent on maximum wattage requirements for Type 1A and 2A headlamps.; I enclose a copy of an interpretation furnished the General Electri Company which states that such a tolerance is allowed. However, to clarify our intent we plan to amend Standard No. 108 in the near future in the manner that you suggest.; Yours truly, Stephen P. Wood, Assistant Chief Counsel |
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ID: aiam4694OpenMrs. Erika Z. Jones Mayer, Brown, & Platt 2000 Pennsylvania Avenue, N.W. Washington, D.C. 20006-1885; Mrs. Erika Z. Jones Mayer Brown & Platt 2000 Pennsylvania Avenue N.W. Washington D.C. 20006-1885; Dear Mrs. Jones: This responds to your letter requesting a confirmatio of your telephone conversation with Mr. Stephen Wood of my staff. In that conversation, he informally stated that the attached letter dated January 5, 1990 from Fidelity Tire Manufacturing Company contained the information necessary to comply with the notification requirements in S5.1 of Federal Motor Vehicle Safety Standard 119 (49 CFR 571.119) for tires and rims not listed in the publication of a specified tire and rim association. This letter confirms that Fidelity's letter would satisfy the requirements of section S5.1. Section S5.1 requires that a listing of the rims which may be used with each tire produced by a manufacturer be provided to the public. The purpose of this requirement is to ensure that the tire will be mounted only on appropriate rims and that the tire will be mounted on vehicles where its load-carrying capacity will be adequate. That section gives manufacturers the option of using the data provided for the tire size and corresponding rims published in certain standardization organization yearbooks or listing the appropriate information 'in a document furnished to dealers of the manufacturer's tires, to any person upon request, and in duplicate to NHTSA .' Fidelity's letter which includes the appropriate dimensional and load-carrying data for the tire and rim appears to satisfy this requirement. I hope this explanation is helpful. Please contact Mr. Marvin Shaw of my staff at (202) 366-2992 if you have any further questions. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam3151OpenMr. W.G. Milby, Manager, Engineering Services, Blue Bird Body Company, P.O. Box 937, Fort Valley, Georgia 31030; Mr. W.G. Milby Manager Engineering Services Blue Bird Body Company P.O. Box 937 Fort Valley Georgia 31030; Dear Mr. Milby: This is in response to your letter of March 29, 1979, requesting a interpretation of Federal Motor Vehicle Safety Standard No. 115 (49 CFR 571.115). We are sorry for the delay in responding.; You wish to know whether the 'body number' that Blue Bird Body Compan assigns to its school buses will satisfy the requirement of S4.5.3.3 that the last six characters of the Vehicle Identification Number (VIN) represent the production sequence of the vehicle. Your concern arises from the fact that the 'body number' does not indicate the true numerical sequence of manufacture. As explained in Notice 5 (43 Fr 36448) and Notice 6 (43 FR 52246) the production sequence represents the 'number sequentially assigned by the manufacturer in the production process' (S4.5.3.3), rather than the numerical sequence of actual manufacture. Consequently, the Blue Bird body number may be used as the production sequence number since the 'body numbers' are sequentially assigned when purchase orders for the buses are received.; Sincerely, Frank Berndt, 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.