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: aiam2737OpenMr. Joe Wall, Assistant Director, Vehicle Inspection Division, Oklahoma Department of Public Safety, 3600 North Eastern, P.O. Box 11415, Oklahoma City, OK 73111; Mr. Joe Wall Assistant Director Vehicle Inspection Division Oklahoma Department of Public Safety 3600 North Eastern P.O. Box 11415 Oklahoma City OK 73111; Dear Mr. Wall: This responds to your letter of December 9, 1977, asking whether th recent amendment of Safety Standard No. 205, *Glazing Materials*, permits the use of plastic glazing in school buses.; The answer to your question is yes. Safety Standard No. 205, as amende December 5, 1977 (42 FR 61465), allows the use of rigid plastic glazing in doors and windows of all buses, including school buses. Please note, however, that plastics cannot be used for bus windshields or in doors or windows to the immediate right or left of the driver.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4030OpenThomas C. Bielinski, Esq., 33 N. Dearborn Street, Suite 1530, Chicago, IL 60602; Thomas C. Bielinski Esq. 33 N. Dearborn Street Suite 1530 Chicago IL 60602; Re: Bartlett v. Wards Dear Mr. Bielinski: The National Transportation Safety Board has forwarded to us for repl your letter of August 29, 1985, asking for information on standards and other regulations regarding the design and manufacture of mopeds.; This agency, the National Highway Traffic Safety Administration, issue the Federal Motor Vehicle Safety Standards which all motor vehicles must meet upon manufacture and initial sale. 'Moped' is not a defined vehicle category under the safety standards but the defined category of 'motorcycle' covers all two-wheeled vehicles such as mopeds. These standards will be found at Title 49 Code of Federal Regulations Part 571 and the applicability section of each standard (either paragraph S3 or S3) will tell you whether it applies to 'motorcycles'. Standards have been adopted for motorcycle brake hoses, (571.106), lighting, (571.108), mirrors (571.111), vehicle identification number (571.115 and Part 565), brake fluids (571.116), tires (571.119), rims (571.120), braking systems (571.122), controls and displays (571.123) and glazing (571.205). Manufacturers must certify compliance with all applicable Federal motor vehicle safety standards (Part 567).; You will find that sections of some of these standards impose a lesse degree of performance upon 'motor-driven cycles'. These are motorcycles producing 5 horsepower or less, and thus include most mopeds of which we are aware.; The individual States are not preempted from having their own standard for area of performance not covered by Federal standards (for covered areas, however, State standards must be identical), and you may also wish to examine the laws of the jurisdiction in which the moped in your case was licensed or being operated.; A manufacturer is required to file an information statement with th agency within 30 days of commencing production (Part 566). If a vehicle fails to conform to a safety standard or contains a safety related defect, its manufacturer must notify the agency, owners and dealers, and remedy the problem (Part 573 and 577).; I hope that this information is useful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1232OpenMr. Gino D'Angelo, Director of State Police, Fiscal Management, New York State Police, Albany, NY 12226; Mr. Gino D'Angelo Director of State Police Fiscal Management New York State Police Albany NY 12226; Dear Mr. D'Angelo: This is in reply to your letter on August 20, 1973, asking that la enforcement vehicles be excluded from a Federal prohibition against headlight flashers.; There is no such prohibition. While paragraph S4.6(b) of Federal Moto Vehicle Safety Standard No. 108 requires headlamps to be steady-burning in use, it also specifically states that 'means may be provided to flash [automatically] headlamps . . . for signalling purposes.' Therefore, manufacturers are not prohibited from equipping vehicles with headlamp flasher units upon customer request.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam4460OpenRobert J. Kaufman, Esq. Gingold, Kaufman & Chaiken 400 Perimeter Center Terrace, N.E. Suite 720 Atlanta, GA 30346-1234; Robert J. Kaufman Esq. Gingold Kaufman & Chaiken 400 Perimeter Center Terrace N.E. Suite 720 Atlanta GA 30346-1234; Re: GK&C File "1012-271 Dear Mr. Kaufman: This responds to your recent lette concerning the advice I gave to a company called Auto Accessories, Inc., with respect to the installation of that company's armrests in Volvo 240 automobiles. More specifically, on behalf of your client, a Volvo dealership, you seek clarification of that advice and request copies of any information, e.g., tests or studies, regarding the armrests. I appreciate your client's concern for safety. For your information, I have enclosed a copy of my November 18, 1987 letter to that company, in which the advice was provided. I have also enclosed a copy of the armrest installation instructions that were proposed by Auto Accessories and discussed in my response. Based on your reading of a letter from Auto Accessories to Volvo dealers (enclosed with your letter), you concluded that the armrest installation procedure 'ostensibly was either approved, mandated, or suggested by the Department of Transportation.' As you will see from my November 1987 letter, the Department did not take any of those actions. This Department has no authority under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.) to approve or endorse any items of motor vehicle equipment or installation procedures therefor. Instead, the Safety Act puts the responsibility on manufacturers to certify that their products comply with the applicable requirements (15 U.S.C. 1403), and obliges manufacturers, distributors, dealers, and motor vehicle repair businesses not to knowingly render inoperative any devices or elements of design in vehicles that were installed in compliance with applicable safety standards (15 U.S.C. 1397(a)(2)(A)). In keeping with this statutory scheme, this agency did not make a determination in the November 1987 letter or on any other occasion that a dealer following the proposed installation instructions would or would not render inoperative a vehicle's compliance with the safety standards. The agency makes such determinations only in the context of an enforcement proceeding. Instead, my November 18 letter pointed out the element of design that might be rendered inoperative by installing the armrests, and advised Auto Accessories as the manufacturer to carefully examine its instructions to determine whether or not following them would result in a 'render inoperative' violation. It appears from the Auto Accessories letter to dealers that that company believes the installation of its armrest would not result in any violations. Our advice to dealers is essentially the same as the advice we gave to Auto Accessories. Dealers should examine the instructions to determine whether following them would render inoperative a vehicle's compliance with Standard No. 208 or any other standard. You may wish to contact Auto Accessories to learn more about the basis for its apparent belief that the installation of its armrest will not violate any requirements of the Safety Act. As for the tests and studies you requested, again, because of our statutory scheme, we have not conducted any regarding the armrest or its installation. We would do so only in the context of an enforcement proceeding. Please let me know if you have any further questions on this subject. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam1398OpenMr. Thomas S. Pieratt, Jr., Executive Secretary, Truck Equipment & Body Distributors Assoc., 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Jr. Executive Secretary Truck Equipment & Body Distributors Assoc. 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in response to your letter of January 30, 1974, requestin information concerning whether or not a certification label is required to be furnished by one who installs a snow plow on a completed vehicle prior to the first purchase of the vehicle for purposes other than resale.; An additional certification label is required when a vehicle is altere by the addition of parts that are not readily attachable components. Whether or not the snow plow is a readily attachable item depends in large part on the manufacturer's intent in designing the vehicle.; If the addition of the snow plow necessitated a change in the weigh ratings of the vehicle, there would be an obligation of the alterer's part to attach an additional certification label in accordance with 49 CFR 567.7.; Thank you for your inquiry. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1662OpenMr. Charles J. Calvin, President, Truck Trailer Manufacturers Association, 2430 Pennsylvania Avenue, N.W., Washington, DC 20037; Mr. Charles J. Calvin President Truck Trailer Manufacturers Association 2430 Pennsylvania Avenue N.W. Washington DC 20037; Dear Mr. Calvin: This responds to your October 23, 1974, question in behalf of Steadma Containers, Ltd., asking if Standard No. 121, *Air brake systems*, applies to the Steadman 'liftainer', which is described as a semi-trailer frame capable of carrying 20- and 40-foot cargo containers that are loaded by means of cranes mounted at each end of the semi-trailer. The vehicle is used to move containers in terminal areas and is used on the highway only in relocation to another terminal.; The 'liftainer' is a motor vehicle as that term is defined in th National Traffic and Motor Vehicle Safety Act of 1966, because it uses the highway on a necessary and recurring basis to move between work sites. A discussion of the motor vehicle definition is enclosed for your information. As a motor vehicle, it is subject to the requirements of Standard No. 121 for trailers, effective January 1, 1975.; I have also enclosed a discussion of Standard No. 121's applicabilit to vehicles purchased by Canadians for use between Canadian and United States points. The standard would apply to Steadman trailers if they are purchased for use on U.S. highways.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0970OpenMr. Bernard W. Weber, Executive Vice President, Wesbar Corporation, Box 577, West Bend, WI 53095; Mr. Bernard W. Weber Executive Vice President Wesbar Corporation Box 577 West Bend WI 53095; Dear Mr. Weber: This is in reply to your letter of January 3, 1973, to Mr. Schneide concerning Motor Vehicle Safety Standard No. 108.; Your first question is whether the standard requires items of lightin equipment to be marked according to SAE Standard J759a. The answer is no. A manufacturer, at his option, may mark equipment items with the symbol DOT as a certification of compliance with Standard No. 108. Standard No. 108 neither prohibits nor requires other marking of equipment. The NHTSA proposed in 1972 that equipment be marked in a manner somewhat similar to J759a but no definitive action has been taken on the proposal.; You also asked whether a clearance lamp could be mounted at 45 degree to serve the functions of both a clearance and side marker lamp, and whether it must bear the SAE designation 'PC' indicating its combination function. Your understanding is correct, that a combination lamp mounted at 45 degrees is permissible if it is successfully tested at that mounting angle for conformance to both clearance and side marker requirements. The designation 'PC' is not a current requirement of Standard No. 108 but has been proposed as the required marking symbol in the rulemaking action referred to earlier.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5621OpenMr. Thomas K. O'Connor Chief of Maintenance and Operations Metropolitan Water Reclamation District of Greater Chicago 100 East Erie Street Chicago, Illinois 60611; Mr. Thomas K. O'Connor Chief of Maintenance and Operations Metropolitan Water Reclamation District of Greater Chicago 100 East Erie Street Chicago Illinois 60611; Dear Mr. O'Connor: This responds to your letter asking about seat bel requirements for a step van with a GVWR greater than 10,000 pounds. You asked whether lap belts versus lap/shoulder belts are needed for compliance with the Federal motor vehicle safety standards. As discussed below, either lap belts or lap/shoulder belts may be used for this type of vehicle. The National Highway Traffic Safety Administration's safety belt installation requirements are set forth in Standard No. 208, Occupant Crash Protection. I note that this standard specifies requirements based on vehicle type and seating position within the vehicle. Different requirements also apply depending on the GVWR of the vehicle. The requirements for trucks with a GVWR of 10,000 pounds or more are set forth in S4.3.2 of Standard No. 208. That section provides vehicle manufacturers a choice of two options for providing occupant crash protection. Option 1, dealing with automatic crash protection, is not relevant to your inquiry. Option 2, set forth in S4.3.2.2, requires vehicle manufacturers to install Type 1 (lap) or Type 2 (lap/shoulder) belts at every seating position. Thus, either lap or lap/shoulder belts may be used to meet S4.3.2. I hope this information is helpful. If you have any further questions, please feel free to call Edward Glancy of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam4933OpenMr. Joe S. Brito Preferred Custom Concepts, Inc. 4107 Kaufman County Road P.O. Box 0069 Crandall, TX 75114; Mr. Joe S. Brito Preferred Custom Concepts Inc. 4107 Kaufman County Road P.O. Box 0069 Crandall TX 75114; "Dear Mr. Brito: This responds to your letter asking about recen changes in this agency's safety standards as they apply to conversion vans. You stated that, 'The recent changes that have occurred in the truck and van conversion industry regarding seats and seat belt restraints have also sparked rumors that this new law will also regulate the use of wood in the interior of a converted vehicle.' You asked if in fact there is some new NHTSA regulation of 'the use of wood in the interior of a converted vehicle.' I am pleased to have this opportunity to explain our regulations to you. The National Highway Traffic Safety Administration (NHTSA) is authorized under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., Safety Act) to issue safety standards applicable to new motor vehicles and items of motor vehicle equipment. NHTSA has exercised this authority to issue Standard No. 208, Occupant Crash Protection. As of September 1, 1991, Standard No. 208 requires, among other things, 'dynamic testing' of manual lap/shoulder safety belts installed at front outboard seating positions of multipurpose passenger vehicles and trucks with a GVWR of 8,500 pounds or less. 'Dynamic testing' means that, after fastening the safety belts around a test dummy, a test dummy occupying a seating position must comply with specified injury criteria in a 30 miles per hour barrier crash test. The specified injury criteria are the head injury criteria (HIC), chest acceleration and deflection, and femur loading. For your information, I have enclosed a copy of our November 23, 1987, final rule adopting the dynamic testing requirements for light trucks. Nothing in the dynamic testing requirements of Standard No. 208 explicitly prohibits the installation of wood in the interior of conversion vans. Indeed, some 1992 luxury passenger cars, which are also subject to crash testing, have wood installed in the vehicle interior. However, wood is a relatively hard surface in a vehicle interior, especially when compared with the padded dashboard, steering wheel, seats, and other components the head may contact in a crash. It would be very difficult for a vehicle to satisfy the injury criteria during dynamic testing if wood were installed in an area contacted by the dummy head during the crash test. Thus, the dynamic testing requirements for conversion vans may effectively limit the interior areas where wood can safely be installed. In addition, van converters are generally small entities that would not have the resources needed to independently certify that their conversion vans comply with the dynamic testing requirements. The simplest way for these van converters to certify compliance with the dynamic testing requirements is to convert the vans in accordance with the specifications provided by the original manufacturer of the van (e.g., Chrysler, Ford, or General Motors). Because of the difficulties in complying with the dynamic testing requirements if wood were installed in an area contacted by the dummy head during the crash test, the original manufacturers of vans may have advised converters in the van specifications not to add wood in the interior areas of the vans. You may wish to contact van converters or original manufacturers to learn if this is the case. Another safety standard that might limit the interior areas where wood can be installed is Standard No. 201, Occupant Protection in Interior Impact. Standard No. 201 specifies performance requirements for certain areas of the vehicle interior compartment, including portions of the instrument panel. Again, while Standard No. 201 does not explicitly prohibit the use of wood, it may be difficult to comply with the requirements of this standard if wood is added to areas subject to Standard No. 201's performance requirements. I have enclosed a current copy of Standard No. 201 for your information. I hope this information is helpful. If you have any more questions about this issue, feel free to contact Mary Versailles at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosures"; |
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ID: aiam0423OpenMr. Stephen C. Royer, Director of Governmental Relations, National Ready Mixed Concrete Association, 900 Spring Street, Silver Spring, MD 20910; Mr. Stephen C. Royer Director of Governmental Relations National Ready Mixed Concrete Association 900 Spring Street Silver Spring MD 20910; Dear Mr. Royer: This is in reply to your letter of March 30, 1971, concerning th applicability (S 573.3) of the Defect Reports regulations (Docket No. 69-31, Notice 2) published February 17, 1971 (36 F.R. 3064). In your letter you ask,; >>>'If a concrete truck mixer manufacturer is notified of a defect (o brakes, for example) and the concrete truck mixer manufacturer relays this information to the incomplete vehicle manufacturer, and the incomplete vehicle manufacturer indicates that he will file the necessary defect reports with [the] Administration and then does not, would . . . [the] concrete truck mixer manufacturer be deemed in violation of Part 573?'<<<; The answer to this question is yes. Under the circumstances yo describe, both the concrete truck mixer and the incomplete vehicle manufacturer would be in violation of the regulation. Neither manufacturer would be in compliance until one of them filed the report in question, which could be either the defect information report required pursuant to S 573.4 or the quarterly report required pursuant to S 573.5.; The NHTSA cannot become involved in disputes between complete an incomplete vehicle manufacturers as to which one of them will furnish the required reports, and the manufacturers concerned must bear the responsibility for deciding this question between themselves.; 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.