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: aiam0089OpenMr. William Butterfield, Product Engineer, Lodal, Incorporated, Kingsford, MI 49802; Mr. William Butterfield Product Engineer Lodal Incorporated Kingsford MI 49802; Dear Mr. Butterfield: Thank you for your letter of June 17, 1968, to the National Highwa Safety Bureau, attention of Mr. Joseph R. O'Gorman, concerning the requirements for rear identification lamps and rear clearance lamps on your EVO Refuse Packer.; Since no mounting height restrictions are specified for rea identification lamps in Motor Vehicle Safety Standard 108, these lamps may be mounted on or below the cross member between the rear wheels. Shielding may be necessary to protect the lamps.; No clearance lamp may be combined optically with any tail lamp o identification lamps. Combination rear clearance and side marker lamps may be used providing the requirements for each are met.; With respect to the requirements of Standard No. 108, I must point ou that this Bureau does not issue approval on items of lighting equipment or on vehicle designs incorporating this equipment. Therefore, the above comments are for your information only and in no way relieve the vehicle manufacturer from his responsibility for certifying that the assembled vehicle meets the requirements of Standard No. 108.; Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam4863OpenMr. Stanley L. Dembecki 2303 N. 44th Street, #14-237 Phoenix, AZ 80058; Mr. Stanley L. Dembecki 2303 N. 44th Street #14-237 Phoenix AZ 80058; Dear Mr. Dembecki: This responds to your letter of March 1, 1991 asking for an 'evaluation' of your 'Flashing' center stop lamp. You have four prototypes: 'complete' one and two bulb units 'for l984 and older vehicles', and one and two 'electronic modules for all third safety brake light retrofits through 1991.' In your opinion, 'since the new safety brake light utilizes the existing brake light (retrofit) on a previously approved brake light assembly it is reasoned that any evaluation as to durability testing is not really needed.' We understand that your 'complete' unit for the older vehicles is a lamp. It is unclear whether the 'electronic module' intended for retrofit for newer vehicles is a separate lamp, or a device to be inserted into an existing lamp. However, the issue that your invention presents is not whether further testing of it is required, but whether it is permitted at all under applicable Federal statutes and regulations. We note that you would like to market it both for installation in passenger cars that already have a center lamp, and in those that do not. In short, you intend to sell the lamp/module in the aftermarket for installation on vehicles in use, rather than as original equipment installed by the manufacturer. Center highmounted stop lamps have been required by Federal Motor Vehicle Safety Standard No. 108 on all passenger cars manufactured on or after September 1, l985 (effectively the l986 model year). You indicate that your lamp flashes momentarily when the brake pedal is applied and thereafter the lamp is steady-burning. Standard No. 108 initially allowed the center lamp to be wired so as to flash with the turn signals but, since September 1, l986, has required the center lamp to be steady-burning at all times when in use. Because your invention is not steady-burning at all times, and is activated by the brake pedal and not the turn signal control, the sale or installation of the invention may be prohibited by Federal law. If this invention is a lamp, it is not a center lamp that conforms to either the initial or current requirements of Standard No. 108 for center lamps. If, on the other hand, it is a module intended for insertion into an existing lamp, its sale or installation could violate existing Federal requirements. The National Traffic and Motor Vehicle Safety Act forbids the sale of equipment that does not comply with a Federal motor vehicle safety standard. If your invention is sold as a lamp, and intended to replace original equipment center lamps on l986 and subsequent model year cars, its sale would be in violation of the Act. On the other hand, there is no similar prohibition on sale of componentry such as an electronic module that would create a noncompliance once installed. However, there is a prohibition on the installation of such componentry (as well as installation of the invention in lamp form on l986 and subsequent model year cars). The Act forbids a manufacturer, distributor, dealer, or motor vehicle repair business from rendering inoperative in whole or in part any equipment on a vehicle which has been installed pursuant to a Federal motor vehicle safety standard. We interpret this as forbidding the installation of equipment that would take a vehicle out of compliance with a Federal safety standard. With respect to l985 model and older cars, which Standard No. 108 did not require to be equipped with center lamps, sale of your lamp exclusively for use on these older vehicles would not violate the Act. However, its installation remains subject to the rendering inoperative prohibition discussed above. There are other Federal standards involving equipment to consider. For example, we would be concerned if your lamp interfered with the field of view of the interior rear view mirror, and if its installation would affect the wiring of the other stop lamps so as to interfere with their design performance. However, there should be no problem with the field of view requirements if the lamp size is comparable to the required center lamps. Once you have satisfied these concerns under Federal law, use of the lamp remains subject to the laws of the individual States in which it is used. We are unable to advise you on these laws, and suggest that you consult for an opinion the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam0573OpenMr. R. W. Ward, Chief Engineer, K-D Lamp Company, 1910 Elm Street, Cincinnati, OH 45210; Mr. R. W. Ward Chief Engineer K-D Lamp Company 1910 Elm Street Cincinnati OH 45210; Dear Mr. Ward: In your letter of January 20 to Mr. Vinson of this office you ask fo an interpretation of paragraph S4.7 'Replacement Equipment' of Motor Vehicle Safety Standard No. 108.; Standard No. 108 applies to motor vehicles manufactured on or afte January 1, 1972. The standard specifies items with which these vehicles must be equipped. The standard also applies to items manufactured on or after January 1, 1972, intended to replace items required by Standard No. 108 to be original equipment on these vehicles. This replacement equipment must be manufactured to conform to Standard No. 108 and certified as meeting all applicable Federal Motor vehicle safety standards.; The standard does not require conformance or certification of item intended as replacement equipment on vehicles manufactured before January 1, 1972 (sic) In this circumstance a manufacturer may continue to manufacture replacement equipment that does not meet Standard No. 108.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4530OpenAIR MAIL; AIR MAIL; Mr. Mamoru Arisaka Manager, Automotive Lighting Homologation Sect Stanley Electric Co., Ltd. 2-9-13, Nakameguro, Meguro-ku Tokyo 153, JAPAN Dear Mr. Arisaka: This is in reply to your letter of July 7, 1988, with respect to a motorcycle lighting device called the 'rolling headlamp.' The headlamp is designed to have its vertical plane always perpendicular to the ground regardless of the inclination of the motorcycle. You have asked whether such a device is legally permissible. Motor Vehicle Safety Standard No. 108 does not prohibit alteration of the mounting angle of a headlamp. Although paragraph S4.3.1 requires each lamp to 'be securely mounted on a rigid part of the vehicle,' your lamp appears to be 'securely mounted' even if it is able to rotate. I hope this answers your question. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1732OpenMr. Eugene Hindin, President, Gindy Mfg. Corporation, Downingtown, PA 19335; Mr. Eugene Hindin President Gindy Mfg. Corporation Downingtown PA 19335; Dear Mr. Hindin: This responds to your November 25, 1974, request for our approval o Gindy's plans to establish the date of completion of manufacture of highway trailers for purposes of compliance with Standard No. 121, *Air brake systems*, which became effective January 1, 1975.; Unfortunately there is no simple formula for a determination in advanc that a trailer is complete. For example, your determination that a vehicle is roadworthy does not establish that it is complete.; We set out what we believe are straightforward criteria in a recen letter to a person concerned with essentially the same problem as you. A copy is enclosed. It can be seen that painting, and the installation of decals, tires, or rims can be accomplished after the date of manufacture. As for special lining arrangements, or the mounting of refrigerator units, this requires a determination by you of whether the trailer is substantially complete without these fixtures.; We do appreciate your efforts to meet the requirements of the standar in good faith, as evidenced by your timely request for guidance and submission of plans. Thank you for your interest in motor vehicle safety.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0820OpenMr. Albert Hammerstein, Robert Bosch GmbH, Department K/BEW3, 7 Stuttgart 30, Postfach 400, Germany; Mr. Albert Hammerstein Robert Bosch GmbH Department K/BEW3 7 Stuttgart 30 Postfach 400 Germany; Dear Mr. Hammerstein: Your Broadview, Illinois, Subsidiary recently forwarded to us a copy o your December 17, 1971, letter concerning aiming adjustment tests as specified in SAE Standard J580a. A search of our files does not reveal that your letter was previously received by this Office.; Specifically, your concern is the interpretation of a requirement whic is specified in SAE J580a as follows:; >>>'2. The mechanism, including the aiming adjustment, must be s designed as to prevent the unit from receding into the lamp body or housing when an inward pressure of 50 lb(sic) is exerted on the outer surface of the lens.'<<<; Our interpretation of the above requirement is that no visible recedin of the sealed beam unit is permitted when the inward pressure is applied on the outer lens surface. Testing for compliance to the requirements of FMVSS No. 108, which references SAE J580a, is conducted on the basis of this interpretation.; In the upcoming Notice of Proposed Rule Making (NPRM) on FMVSS No. 10 (Docket 69-19), we are considering the feasibility of specifying more objective type requirements on this aspect of aiming adjustment tests for headlamps. You will no doubt be interested in commenting on the proposed requirements after issuance of the NPRM.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam1698OpenMr. Donald J. McGee, Vice President, H & H Equipment Co., 6050 14th Street, Detroit, MI 48208; Mr. Donald J. McGee Vice President H & H Equipment Co. 6050 14th Street Detroit MI 48208; Dear Mr. McGee: This is in response to your letter of November 20, 1974, asking whethe a 'moving van' trailer which utilizes an air over hydraulic brake system is required to comply with Standard No. 121, *Air brake systems*.; 'Air brake system' is defined in S4. of the standard as 'a system tha uses air as a medium for transmitting pressure or force from the driver control to the service brake, but does not include a system that uses compressed air or vacuum only to assist the driver in applying muscular force to hydraulic or mechanical components.'; Since your trailer utilizes air as a medium for transmitting force fro the trailer 'glad hands' to the air/hydraulic actuator, it qualifies as an air brake system and must comply with Standard No. 121.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam4160OpenThe Honorable Glenn M. Anderson, Chairman, Subcommittee on Surface Transportation, U.S. House of Representatives, Room 2165, Rayburn House Office Building, Washington, DC 20515; The Honorable Glenn M. Anderson Chairman Subcommittee on Surface Transportation U.S. House of Representatives Room 2165 Rayburn House Office Building Washington DC 20515; Dear Mr. Anderson: Thank you for your letter forwarding correspondence from Congressma Howard Wolpe who contacted you on behalf of his constituent, Mr. Dennis D. Furr of Lansing, Michigan. Mr. Furr wrote to Congressman Wolpe with several questions pertaining to the regulations we administer for school buses. I appreciate this opportunity to respond to Mr. Furr's concerns regarding school bus safety.; I would like to begin with some background discussion of our school bu regulations. Our agency has two sets of regulations for school buses that were issued separately under the National Traffic and Motor Vehicle Safety Act ('the Vehicle Safety Act') and the Highway Safety Act. The first set, issued under the Vehicle Safety Act, applies to the manufacture and sale of new vehicles and includes our motor vehicle safety standards for school buses. In 1974, Congress amended the Vehicle Safety Act to direct NHTSA to issue motor vehicle safety standards for various aspects of school bus safety, including emergency exits, seating systems and occupant crash protection, rollover protection, and fuel systems. The standards we issued became effective April 1, 1977 and apply to each school bus manufactured on or after that date. Under the Vehicle Safety Act, each person manufacturing or selling new buses must ensure that the vehicles comply with our school bus safety standards if intended for school use.; Some of Mr. Furr's concerns involve one of our school bus safet standards, Federal Motor Vehicle Safety Standard No. 222, *School Bus Passenger Seating and Crash Protection*. Mr. Furr believes that some State laws permit excessive numbers of children to be transported in school buses which he contends can result in unsafe seating configurations (such as a row of bench seats with one inch of aisle space). He suggests revising Standard No. 222 to require a 'three-two seating arrangement,' which we assume refers to school bus seat design and positioning.; We believe that an amendment to Standard No. 222 along the line suggested by Mr. Furr is not warranted. We are not aware of any data indicating that there is a safety problem with current school bus seating configurations or that manufacturers are or have been placing bench seats in a manner that prevents or impedes access through school bus aisles. In accordance with current requirements of Standard No. 222, manufacturers must provide high levels of crash protection for each designated seating position in their school buses, regardless of the configuration of a vehicle's seating. School bus seats are also subject to requirements ensuring access to school bus exits. The possibility that a State might permit loading school buses over the vehicles' rated seating capacity would not affect the manufacturers' and sellers' responsibilities under the Vehicle Safety Act to ensure that their school buses comply with this and other applicable safety standards.; As to Mr. Furr's concerns about school bus seat dimensions, please se the enclosed copy of a letter sent by NHTSA to Senator Donald Riegle, Jr., who contacted us with a similar inquiry on Mr. Furr's behalf regarding Standard No. 222's requirements for seat configuration.; The second suggestion from Mr. Furr was to amend Standard No. 222 t require safety belts for school bus passengers. Standard No. 222 currently does not require safety belts for passengers in large school buses (those with gross vehicle weight ratings greater than 10,000 pounds) because large school buses are already required to provide high levels of protection to passengers through a concept called 'compartmentalization.' Compartmentalization requires that the interior of large buses be improved so that children are protected without the need to fasten safety belts. The seating improvements include higher and stronger seat backs, additional seat padding, and better seat spacing and performance. Our safety standards do require safety belts for passengers in smaller school buses since those buses do not offer the same protection as that provided by compartmentalization.; Since large school buses already offer substantial protection t passengers, we believe that a safety standard requiring safety belts in those buses is not warranted at this time. However, we do not prevent State and local governments from ordering safety belts on their large school buses if they wish to do so. Most school bus manufacturers are capable of installing them in new school buses.; Issues relating to safety belts in large school buses are discussed i NHTSA's publication entitled, 'Safety Belts in School Buses,' (June 1985). I have enclosed a copy of the report for your information.; It appears from Mr. Furr's several suggestions for amending Standar No. 222 that his primary concern is with State regulations specifying how many children are permitted to be carried on school buses. It might be helpful to keep in mind a distinction between performance requirements, which apply to school bus manufacturers and sellers and are set by NHTSA, and operational requirements for school buses, which apply to bus users and are set by the States. We have recommendations for school vehicle use requirements, which I will discuss below in connection with the balance of Mr. Furr's letter.; Mr. Furr's other questions relate to the second set of regulations w issued for school buses under the authority of the Highway Safety Act. Those regulations, which are more in the nature of guidelines, comprise recommendations for operating school buses and apply to Federal funding of State highway safety programs. Highway Safety Program Standard No. 17, *Pupil Transportation Safety* (copy enclosed), which Mr. Furr references, includes recommendations that States provide seating accommodations of minimum specified dimensions for each school bus occupant and that States coordinate seating plans to eliminate standees. Each state determines how it will include Program Standard No. 17's guidelines in its highway safety program, and this agency does not insist on adoption of the standard.; Mr. Furr asks about Michigan's implementation of Program Standard No 17. Since Michigan state officials have informed him that the State has chosen not to adopt the standard, Mr. Furr asks if Michigan has either disregarded Federal funds or has accepted Federal funding and neglected to comply with Program Standard No. 17.; The answer to both of those questions is no. NHTSA administers annuall highway safety grant funds to the States to enable States to establish and implement their highway safety programs in accordance with the program standards we issued. In qualifying for Federal funding under our grant program, States are given discretion about adopting Program Standard No. 17. Michigan is thus not subject to sanctions for receiving Federal funding for its highway safety program in the absence of its implementation of that standard.; In a related comment, Mr. Furr suggested NHTSA withhold highway safet funds to any State that does not require the use of safety belts on school buses. As explained above, NHTSA's funding program for highway safety programs does not penalize States for implementing Standard No. 17 in the manner in which they have chosen. Further, it would be inappropriate for NHTSA to impose sanctions against States that do not require safety belts on large school buses since we do not believe safety belts for passengers on those vehicles are necessary at this time.; I hope this information is helpful. Please contact my office if yo have any further questions.; Sincerely, Diane K. Steed |
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ID: aiam1362OpenMr. Arden H. Faris, Assistant Director, American Retreader's Association, Inc., P.O. Box 17203, Louisville, Kentucky 40217; Mr. Arden H. Faris Assistant Director American Retreader's Association Inc. P.O. Box 17203 Louisville Kentucky 40217; Dear Mr. Faris: This is in reply to your letter of November 20, 1973, asking under wha conditions retreaded tires, which you describe as, 'not first class mainly from the standpoint of appearance,' may be sold. You state that the tires are not defective, and are being sold for non-highway use, such as for farm wagons and hay bailers.; Standard No. 117 (Retreaded pneumatic tires) applies to all retreade tires manufactured for use on passenger cars. The sale of such tires for off-highway vehicular purposes does not remove them from the coverage of the standard. Consequently, the tires must comply fully with Standard No. 117, bear the manufacturer's identification number (49 CFR Part 574), and not be restricted to off-road operation.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam1677OpenMr. Kenneth Winiarski, Field Enterprises Education Corp., Merchandise Mart Plaza, Chicago, Illinois 60654; Mr. Kenneth Winiarski Field Enterprises Education Corp. Merchandise Mart Plaza Chicago Illinois 60654; Dear Mr. Winiarski: Your letter of October 8, 1974, to Mr. Bobby Boaz has been forwarded t this office for reply. You appear to be interested in obtaining some general statements regarding the applicability of motor vehicle safety standards to different types of motor vehicles.; We attempt to apply each Federal motor vehicle safety standard to a wide range of motor vehicles and motor vehicle equipment as is reasonable, practicable and appropriate. It is not entirely accurate, however, to say that the standards apply to the performance of equipment which vehicles are required to have. The standards are divided conceptually into three types: those which apply to new vehicles, those which apply to motor vehicle equipment (*e.g.* tires, child seats, etc.) and those which apply to both vehicles and equipment. In case of a standard which applies to vehicles, the tests employed by the standard can take into account vehicle structure, weight, and design. In other words it is the method by which equipment is integrated into a vehicle that is important, rather than the performance of equipment taken alone.; Standards which apply to vehicles specify the particular vehicle type to which they apply. Most early vehicle standards applied only to passenger cars. Since that time we have attempted to expand the applicability of some of these standards to other vehicle types. In each case, as I indicated above, a standard must be reasonable, practicable, and appropriate for the type of vehicle to which it is applied. In some cases, this is a matter of technology as you suggest. In other, however, the question may be one of safety need. For example, some standards do not apply to trailers (*e.g.*, Standard No. 302, 'Flammability of interior materials') or to equipment for use in trailers (No. 205. 'Glazing materials') because State laws prohibit people from riding in trailers. In this regard standards can also be directed at particular vehicle types to alleviate safety problems particular to them. A good example of this is Standard No. 217, 'Bus window retention and release.'; Your statements regarding seat belts and the applicability of Standard No. 208,209, and 210 are not correct. While these requirements are somewhat complex, I believe an appropriate summary would be that seat belts and anchorages are required at all permanent seating positions including lateral or rearward positions, in all motor vehicles except trailers, motorcycles, and the passenger seats in buses.; Yours truly, Richard B. Dyson, 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.