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: aiam4237OpenThe Honorable Slade Gorton, United States Senate, Washington, DC 20510; The Honorable Slade Gorton United States Senate Washington DC 20510; Dear Senator Gorton: Thank you for your November 3, 1986, letter on behalf of you constituent, Mrs. Laurel Kuther of Clarkston, who asks that safety belts be required on school buses. Your letter has been referred to my office for reply, since the National Highway Traffic Safety Administration (NHTSA) is responsible for administering Federal programs relating to school bus safety.; I appreciate this opportunity to respond to your concerns. As explaine below, NHTSA does not require large school buses to have safety belts for passengers because we require those buses to provide an alternate form of passenger crash protection. Our safety standards are directed at improving the interior of large school buses so that passengers will be provided adequate crash protection even if safety belts are not used.; I would like to begin with some background information on our schoo bus regulations. NHTSA is responsible for developing safety standards applicable to all new motor vehicles, including school buses. In 1977, we issued a set of motor vehicle safety standards for various aspects of school bus safety. Included in that set is Federal Motor Vehicle Safety Standard No. 222, *School Bus Passenger Seating and Crash Protection*. Standard No. 222 requires large school buses--i.e., those with gross vehicle weight ratings over 10,000 pounds--to provide passenger crash protection through a concept called 'compartmentalization.' Compartmentalization requires that the interior of large buses be improved so that children are protected regardless of whether they have fastened a safety belt. The seating improvements include higher and stronger seat backs, additional seat padding, and better seat spacing and performance.; Our safety standards require a safety belt for the school bus drive since the driver's position is not compartmentalized. We also require safety belts for passengers in smaller school buses because those buses experience greater crash forces than do larger buses and the additional restraint system is needed to provide adequate crash protection for passengers.; However, because large school buses already offer substantia protection to passengers and a Federal endorsement for safety belts in those vehicles is unnecessary. In addition to meeting Federal school bus safety standards, large school buses are very safe vehicles because of their size and weight, the training and experience of their drivers and the extra care that other road users employ in the vicinity of school buses. NHTSA does not prevent States and local jurisdictions that wish to order safety belts on their own large buses from doing so. Such a decision is a matter for the officials of the particular State or local jurisdiction, who are best able to assess their own pupil transportation needs.; A June 1985 NHTSA publication entitled, 'Safety Belts in School Buses, discusses many of the issues relating to safety belts in large school buses. I have enclosed a copy of the report for your information.; I hope you have found this information to be helpful. If you or you constituent have any further questions, please do not hesitate to contact me.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1465OpenMr. Robert E. Langdon III, 2511 West 7th Street, Los Angeles, California 90057; Mr. Robert E. Langdon III 2511 West 7th Street Los Angeles California 90057; Dear Mr. Langdon: This is in reply to your letter of April 12, 1974, asking whethe retreaded tires are required by Motor Vehicle Safety Standard No. 117 to have either a ribbed tread pattern or treadwear indicators.; Standard No. 117 does not have requirements for tread pattern design and thus retreaded tires need not have a ribbed tread design. Each retreaded tire must, however, in accordance with S5.1.1(b) of Standard No. 117, incorporate a treadwear indicator that will provide a visual indication that the tire has worn to a tread depth of 1/16 inch.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3458OpenMr. W. D. Smith, Acting Chief of Staff, United States Marine Corps, Marine Corps Logistics Base, Barstow, CA 92311; Mr. W. D. Smith Acting Chief of Staff United States Marine Corps Marine Corps Logistics Base Barstow CA 92311; Dear Mr. Smith: This responds to questions raised in your June 23, 1981 letter whic was referred to us by Mr. Zemaitis of our regional office. In your letter, you ask for exemption of your vehicles from several Highway Safety Program Standards relating to school buses.; As Mr. Zemaitis indicated, the Highway Safety Program Standards ar applied by the States. If the States deem it appropriate to provide exemptions in the limited type of circumstances described in General Shaffer's May 15, 1981 letter to the California Highway Patrol, they are permitted to do so. Accordingly, I suggest that the Marine Corps again contact the appropriate State officials for the exemption you desire.; The National Highway Traffic Safety Administration has always exempte military vehicles from its Federal Motor Vehicle Safety Standards. This exemption is codified in Volume 49 of the Code of Federal Regulations at Part 571.7(c). You may want to point this out to California officials and ask them to adopt a similar exemption policy with respect to your vehicles.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4667OpenMr. Don James Contracts Stone Bennett Corporation l4l9 Upfield Drive Carrollton, Texas 75006; Mr. Don James Contracts Stone Bennett Corporation l4l9 Upfield Drive Carrollton Texas 75006; "Dear Mr. James: This responds to your letter concerning Federal Moto Vehicle Safety Standard No. l02, Transmission Shift Lever Sequence, Starter Interlock, and Transmission Braking Effect. You asked about the standard's display identification requirements for automatic transmission vehicles without a gear shift lever park position. Your questions are addressed below. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles and equipment meet all applicable requirements. The following represents our opinion based on the facts provided in your letter. Standard No. l02 sets forth the following display identification requirements for automatic transmission vehicles without a gear shift park position: S3.l.4 Identification of shift lever positions. . . . S3.l.4.2 Except as specified in S3.l.4.3, if the transmission shift lever sequence does not include a park position, identification of shift lever positions, including the positions in relation to each other and the position selected, shall be displayed in view of the driver at all times when a driver is present in the driver's seating position. S3.l.4.3 Such information need not be displayed when the ignition is in a position that is used only to start the vehicle. You asked about several similar designs for shift control consoles. In addition to including a mechanism for shifting the transmission (push buttons or toggle levers), the consoles incorporate a display which lists the particular gear position which has been selected, e.g., 'R' for reverse. No other gear positions are shown. In at least some of the designs, the display is an electronic one. You asked about the 'acceptability' of providing a label indicating the gear position sequence on the body of the shift control console, e.g., '1 2 D N R.' Drawings provided with your letter indicate that the label would be provided directly adjacent to the gear position display. As indicated above, section S3.l.4.2 requires identification of shift lever positions, including the positions in relation to each other and the position selected, to be displayed in view of the driver. While your designs do identify the gear position selected, they do not, in the absence of an added label, identify the shift lever positions in relation to each other. The additional label would, however, provide such information. Section S3.l.4.2 also requires that the specified information be displayed in view of the driver at all times when a driver is present in the driver's seating position (except when the ignition is in a position that is used only to start the vehicle). The times when display is required includes situations in which the ignition is 'off.' Since your designs use electronic technology to identify the gear position selected, a vehicle equipped with your design might not meet this requirement, at least in the absence of a device which activates the display whenever a driver is present. It is our understanding that 'permanent' display is not possible with electronic technology, due to battery drain. However, if the gear position display is turned off with the ignition (the most obvious means of avoiding battery drain), this requirement would not be met. This is because the display would not function when a driver is in the driver's seating position (before leaving the vehicle or upon entering the vehicle at a later time) while the ignition is 'off.' As you are aware, NHTSA has proposed new requirements for the purpose of facilitating the use of electronic technology. See 55 FR l226, January l2, l990. If amendments are adopted based on that proposal, the analysis presented above could change. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam2160OpenMr. Jack Gromer, Timpte, Inc., 5990 N. Washington Street, Denver, CO 80216; Mr. Jack Gromer Timpte Inc. 5990 N. Washington Street Denver CO 80216; Dear Mr. Gromer: This responds to Timpte's December 10, 1975, question whethe modification of a certified trailer prior to retail sale constitutes the manufacture of a vehicle subject to applicable safety standards such as Standard No. 121, *Air Brake Systems*.; The answer to your question is no. From your description, it appear that the proposed modification would be an alteration of a certified vehicle subject to S 567.7 of NHTSA certification regulations (49 CFR S 567.7) (copy enclosed). Under that section, conformity of the vehicle as altered need only be to standards in effect at the time the originally certified trailer was manufactured.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2530OpenMr. W. G. Milby, Manager, Engineering Services, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Manager Engineering Services Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to your February 9, 1977, letter asking whether 1 described intersections of bus body components qualify as 'body panel joints' subject to the requirements of Standard No. 221, *School Bus Body Joint Strength*.; The terms which establish the applicability of the requirements of th standard to a particular section of a school bus body are defined in S4 of the standard. Read together, they establish the following test. If the edge of a surface component (body panel) that encloses occupant space comes into contact or close proximity with any other body component, the requirements of S5 apply, unless the area in question is designed for ventilation or another functional purpose or is a door, window or maintenance access panel. Applying this test to the 10 intersections of bus body components you describe, it appears that none of them are required to comply with the standard.; The joints numbered 1 through 4 on page 1 of your letter refer t hanger straps, panels and pads involved in the installation of overhead storage racks. These items of equipment are not considered to have a function in enclosing occupant compartment space and, therefore, are excluded from the standard's requirements.; The exterior roof luggage rack described in paragraphs 5 and 6 is no considered to have a function in enclosing occupant space and, therefore, is not considered a body component for purposes of the requirements. For purposes of testing the complex joints to which the rack is fastened, it should be modified as necessary to prevent it from affecting testing of the underlying joint.; The NHTSA agrees that the joints described in paragraphs 1 through 4 o page 2 of your letter, relating to the installation of air conditioning units, involve the type of ventilation space that is not subject to the requirements for joint strength.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2863OpenMr. Alberto Negro, Fiat, Research & Development - U.S.A. Branch, Parklane Towers West Suite 1210, Dearborn, MI 48126; Mr. Alberto Negro Fiat Research & Development - U.S.A. Branch Parklane Towers West Suite 1210 Dearborn MI 48126; Dear Mr. Negro: This responds to your June 16, 1978, letter asking whether manufacturer is permitted to list on the certification label required by Part 567, *Certification*, the gross axle weight rating (GAWR) in kilograms as well as pounds. The National Highway Traffic Safety Administration has permitted the use of kilograms on the certification label as long as the label continues to list the GAWR in pounds also.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3771OpenThe Honorable Robert A. Young, Member of Congress, 4150 Cypress Road, St. Ann, MO 63074; The Honorable Robert A. Young Member of Congress 4150 Cypress Road St. Ann MO 63074; Dear Mr. Young: Thank you for your letter of October 13, 1983, concerning the potentia hazards posed to law enforcement officials by the use of opaque glass in automobiles. Through the exercise of its motor vehicle safety authority, the agency has addressed a part of this potential problem. However, given the limitations on the agency's authority, additional State action is needed to eliminate this potential problem.; Pursuant to the National Traffic and Motor Vehicle Safety Act, th agency has issued Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials*, which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70 percent in areas requisite for driving visibility, which includes all windows in passenger cars) and abrasion resistances. The specification for light transmittance precludes darkly-tinted windows in new automobiles.; In past interpretation letters, the agency has said that solar film an other materials used to make windows opaque are not glazing materials themselves and would not have to comply with Standard No. 205. However, installation of such films on new motor vehicles would be prohibited if the vehicle glazing no longer complied with the light transmittance of abrasion resistance requirements of the standard. If a manufacturer or a dealer places the film on glazing in a vehicle prior to the first sale of the vehicle, that manufacturer or dealer has to certify that the glazing continues to be in compliance with the requirements of Standard No. 205.; After a new vehicle has been sold to the consumer, he may alter th vehicle as he pleases, so long as he adheres to all State requirements. Under Federal law, the owner could install the tinting or other film on glazing in his vehicle whether or not the installation adversely affected the light transmittance and abrasion resistance of the glazing. Section 108(a)(2)(A) of the Vehicle Safety Act provides 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 motor vehicle in compliance with an applicable motor vehicle safety standard. 'Render inoperative' means to remove, disconnect or degrade the performance of a system or element of design installed to comply with a Federal safety standard. Thus, none of those persons may knowingly install a tinting or other film on a vehicle for an owner if that action would render inoperative the light transmittance or abrasion resistance performance of the vehicle's glazing. Violation of the render inoperative provision can result in Federal civil penalties of up to $1,000 for each violation.; State law, rather than Federal law, governs the operational use o vehicles by their owners. Thus, it is up to the States to preclude owners from applying tinting or other films to their vehicle windows. A number of States have already adopted such laws. The agency would be glad to provide technical assistance on glazing requirements to the appropriate Missouri highway safety officials working on this problem.; I hope this explains the agency's authority to address the potentia problems posed by tinting and other films. If you need further information, the agency will be glad to provide it.; Sincerely, Diane K. Steed |
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ID: aiam3321OpenMr. Terry Coleman, Codes and Safety Manager, Airstream, Jackson Center, OH 45334; Mr. Terry Coleman Codes and Safety Manager Airstream Jackson Center OH 45334; Dear Mr. Coleman: This responds to your June 13, 1980, letter asking whether your compan would be considered a chassis-cab manufacturer subject to the labeling requirements of Part 567, *Certification*. You indicate that you take another manufacturer's incomplete chassis with a motor and add to it a cab and body with bumpers, mirrors, and exterior trim. This vehicle is then sent to a final-stage manufacturer for final completion. We would not consider you to be a chassis-cab manufacturer subject to the certification requirements.; As you know, a chassis-cab is defined in Part 567 as 'an incomplet vehicle, with a completed occupant compartment, that requires only the addition of cargo carrying, work performing, or load bearing components to perform its intended functions.' The incomplete vehicle upon which your manufacturing operation begins is simply a chassis without the cab. As such, that vehicle is subject to the incomplete vehicle document requirements of Part 568, but it is not subject to the chassis-cab certification requirements.; Your modification adds on a bus body which then needs final work befor it can be used. Since you do not complete the occupant compartment as required by the definition of 'chassis-cab', you are not required to attach a certification label. You are simply an intermediate manufacturer. The final- stage manufacturer would attach the only label to the vehicle.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2926OpenMr. Paul G. Scully, Chairman, SAE Lighting Committee, State Road 7, P.O. Box 766, Madison, IN 47250; Mr. Paul G. Scully Chairman SAE Lighting Committee State Road 7 P.O. Box 766 Madison IN 47250; Dear Mr. Scully: This is in reply to your letter of December 18, 1978, asking for a interpretation of Federal Motor Vehicle Safety Standard No. 108.; The standard was recently amended to establish a ceiling of 60 inche from the roadway surface for the mounting height of rear side marker lamps. You have asked whether it is permissible to mount an additional side marker lamp at the upper rear corner of a trailer whose overall height exceeds 60 inches.; The answer is yes. Such a supplemental lamp would not appear to impai the effectiveness of lighting equipment required by Standard No. 108, within the meaning of the prohibition of S4.1.3 that you mentioned.; Sincerely, Joseph J. Levin, Jr., 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.