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: aiam0509OpenMr. Joseph W. Kennebeck, Safety Project Engineer, Volkswagen of America, Inc., Englewood Cliffs, NJ 07632; Mr. Joseph W. Kennebeck Safety Project Engineer Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Kennebeck: This is in reply to your letter of August 26, 1971, in which you aske our opinion on how to position a 50th percentile 6-year-old child in determining the conformity of a seat belt warning system to S7.3.1(c) of Standard No. 208. Our opinion is that the child should be positioned with his back against the back of the seat and his head upright, in the posture in which he would be held by the seat belt if it were buckled around him as specified in S7.1. This is the position what will be used in our tests for conformity to S7.3.1(c).; The language that you cite from S8.1.11(b) of the standard ('norma upright sitting posture') is applicable to the position of test devices during the dynamic tests specified in S4 and S5, but is not applicable to the belt adjustment and warning system requirements of S7. The position that we intend to use under S7.3.1(c) is therefore not based on any definition of 'normal upright sitting posture.'; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2534OpenMr. William A. Bertolini, President, Bertolini Engineering Co., Inc., Butler Professional Center, 1375 Route 23, Butler, NJ 07405; Mr. William A. Bertolini President Bertolini Engineering Co. Inc. Butler Professional Center 1375 Route 23 Butler NJ 07405; Dear Mr. Bertolini: This responds to your March 7, 1977, letter asking whether you proposed remanufacture of 573 trailer chassis would constitute the manufacture of new chassis which would be required to conform to Standard No. 121, *Air Brake Systems,* or any other applicable regulation.; According to the remanufacture proposal you describe, Seatrain Line will be the user of the chassis both before and after the remanufacture, although it will no longer own any of them. Fruehauf Corporation will become the owner of all of the chassis, whereas it currently owns none.; The NHTSA regulations pertaining to the remanufacture of chassis ar found in 49 CFR Part 571.7. In that regulation the agency states that the chassis must be owned or leased by the same entity both before and after remanufacture. Since Seatrain is the current user of the vehicles (as owner and lessee) and will continue to be the user after remanufacture (as a lessee), it appears that the remanufactured vehicle will not be one that requires certification with motor vehicle safety standards.; It should be pointed out that if the transaction you describe fo achieving remanufacture becomes a large-scale practice in the trailer industry, the agency will be compelled to reconsider the meaning of 'manufacture' under its regulations.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam3775OpenMr. H. Nakaya, Mazda (North America), Inc., 23777 Greenfield Road, Southfield, MI 48075; Mr. H. Nakaya Mazda (North America) Inc. 23777 Greenfield Road Southfield MI 48075; Dear Mr. Nakaya: This responds to your October 13, 1983 letter regarding th classification of certain hypothetical mini- van models as either passenger cars, multipurpose passenger vehicles, or trucks for purposes of complying with Federal motor vehicle safety standards.; Your first question involved the effect of changes in floor pa geometry on this classification. You postulate separate cargo and passenger versions of the mini-van, with each version using identical suspension, steering and driveline components and each vehicle being of unibody construction. However, slight differences would exist in the floor pans of the two vehicles, with the passenger version having a lowered floor pan section to accommodate the rear seat.; Assuming that the cargo version has greater cargo-carrying volume tha passenger carrying volume (see, e.g., 49 CFR Part 523), we would consider that version to be a truck. (In the unlikely event the cargo version does not have that ratio of volumes, all versions of the mini-van would probably be considered passenger cars.) Since the passenger version of a mini-van would almost certainly have greater passenger-carrying volume than cargo carrying volume, that vehicle would be treated as a passenger car unless it meets the agency's 'multipurpose passenger vehicle' definition. That definition provides, in relevant part, that an MPV is a motor vehicle designed to carry 10 people or less and which is constructed on a 'truck chassis.' The 'chassis' of a vehicle includes the vehicle's power train as well as its entire load supporting structure. In the case of a vehicle using unibody construction, this load supporting structure would technically include the floor pan.; The fact that a common chassis is used in a family of vehicles, on member of which is classified as a 'truck,' is evidence that the common chassis is a 'truck chassis.' However, further evidence is needed to demonstrate that the chassis has truck attributes, such as information showing the design to be more suitable for heavy duty, commercial operation than a passenger car chassis. This further evidence is necessary since otherwise the introduction of a cargo carrying version of an existing passenger car could result in the reclassification of the passenger car into an MPV, if the agency only considered the issue of whether a common chassis is used. For example, in the past, certain station wagons have been marketed without rear seats and with other modifications which render them the functional equivalent of a cargo van. The agency does not believe it to be appropriate in such a situation to reclassify the basic station wagon as an MPV.; The floor pan differences mentioned in your first question do no appear to be so significant as to require treating the two mini-van versions as having different chassis. The agency does not consider minor floor pan differences to negate the fact that two versions of the same family of vehicles employ the same 'chassis,' since to do so would likely mean that no unibody vehicles could be classified as MPV's. However, in the absence of any information regarding the extent to which the common chassis has truck-like attributes, we cannot state whether the vehicle would be treated as an MPV.; Your second question involves the effect of various seating designs o whether a unibody constructed mini-van is classified as an MPV. Since the seats are not part of the vehicle chassis, these variations should have no impact on whether the vehicle is an MPV. (Fuel economy classifications are dependent on seat configuration however--see 49 CFR Part 523.); Your third question involves the significance of the relative sale levels, order of introduction, and actual existence of two versions (cargo and passenger) of the mini-van. In theory, a passenger version of a mini-van could be classified as an MPV even if no cargo version were offered in the U.S. or indeed if none were ever produced. In such a situation, however, the manufacturer would be under a heavy burden to demonstrate that what is sold as a passenger carrying vehicle in fact has a 'truck chassis,' with heavy duty, commercially suited attributes. The existence of a truck version, and the fact that the truck version was either designed first or was the principal focus of the design would be additional factors which would tend to indicate that the chassis is a truck chassis.; If you have further questions in this matter, please contact us. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1748OpenHonorable Charles Wilson, House of Representatives, Washington, DC 20515; Honorable Charles Wilson House of Representatives Washington DC 20515; Dear Mr. Wilson: This responds to your request for consideration of Mr. J. M. Chandler' December 31, 1974, request for reconsideration of Standard No. 121, *Air brake systems*, because of its costs.; Standard No. 121 requires that newly- manufactured air-braked vehicle stop from speeds of up to 60 mph on wet and dry surfaces in the loaded and unloaded condition, without leaving a 12-foot-wide lane and without lockup of wheels above 10 mph. These performance requirements are based on a safety need for improved braking performance on air brake- equipped highway vehicles. Controlled stopping within the traffic lane is particularly important to tractor-trailer combinations to avoid 'jackknife' skids. The incompatibility of vehicle sizes can be reduced significantly by establishing equal stopping distances for trucks and passenger cars.; We have analyzed the costs and benefits to be gained in upgradin truck, bus, and trailer braking performance and have concluded that the savings in lives, injury, and property damage justify the incremental costs of this standard. Standard 121 does not require retrofit of vehicles manufactured prior to the standard's effective date.; From a cost standpoint, it is noteworthy that the arguments fo increased weight limits for commercial vehicles relied, in part, on the increased braking performance of vehicles which meet Standard No. 121. A major reason for the heavier vehicles would be to reduce the costs of transportation, and Standard No. 121 contributes directly to that goal.; As you may be aware, the NHTSA has in fact proposed postponement of th standard due to the current economic situation. Based on several hundred comments, there was persuasive evidence that a delay at this late date would create far greater dislocation in the automotive industry than would a January 1, 1975, implementation. A copy of our decision not to postpone the standard is enclosed.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam2867OpenMr. Robert B. Kurre, Director of Engineering, Wayne Corporation, P.O. Box 1447, Industries Road, Richmond, IN 47374; Mr. Robert B. Kurre Director of Engineering Wayne Corporation P.O. Box 1447 Industries Road Richmond IN 47374; Dear Mr. Kurre: This responds to your recent letter asking whether Safety Standard No 208 applies to side-facing seats in multipurpose passenger vehicle vans. You also ask to be advised of the criteria to be used for the installation of seat belts in these vehicles.; Safety Standard No. 208, *Occupant Crash Protection*, does require sid facing seats in multipurpose passenger vehicles to comply with one of the options under paragraph S4.2.2, since the side-facing seats in question would be considered designated seating positions. If a manufacturer chooses to install seat belts under one of the options of that paragraph, the seat belt assemblies must comply with Safety Standard No 209, *Seat Belt Assemblies*, and Safety Standard No. 210, *Seat Belt Anchorages*.; Safety Standard No. 210 does exempt side-facing seats from its strengt requirements, but all other requirements of the standard would be applicable. However, we strongly recommend that belt anchorages for side-facing seats be of at least equivalent strength to anchorages for forward and rearward facing seats, since the strength specifications are only minimum performance requirements. Side-facing seats were excepted from the strength requirements specified in the standard because the forces acting on side-facing seats are different from those acting on forward or rearward facing seats and the requirements and procedures were specifically developed for these latter seats.; Please contact this office if you have any further questions. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3325OpenMr. David R. Stevens, Quality Control Manager, Columbia Manufacturing Company, Westfield, Massachusetts 01085; Mr. David R. Stevens Quality Control Manager Columbia Manufacturing Company Westfield Massachusetts 01085; Dear Mr. Stevens: This is in response to your letter of June 17, 1980, and i confirmation of your several telephone conversations with Mr. Schwartz of my office.; In your letter, you asked whether the vehicle identification numbe (VIN) required by Federal Motor Vehicle Safety Standard No. 115 (46 CFR 571.115) must reflect each of your 16 moped 'models' if the differences between the models are cosmetic. Table 1 of S4.5.2 requires that the following information be encoded in the VIN of the motorcycles: Type of motorcycle, line, engine type, and net brake horsepower. The encoding of models is not required. 'Line' is defined in S3. *Definitions* to mean a name which a manufacturer applies to a family of vehicles within a make which have a degree of commonality in construction, such as body, chassis or cab type. Therefore, if the 16 moped 'models' are of the same construction, they would not be considered different lines unless Columbia chose to designate them as different lines.; You have also stated that Columbia has changed its moped moto manufacturer and has made minor modifications in its open frame moped. You wish to know if this must be reflected in the VIN. The VIN Standard for mopeds does not take effect until September 1, 1980, for vehicles whose model year changeover date occurs prior to September 1, 1980, and subsequent to January 1, 1981, and until the actual model year changeover date for vehicles whose model year changeover date falls between these two dates. Therefore, any changes Columbia has made prior to the effective date of the standard would presumably already be reflected in the VIN.; The National Highway Traffic Safety Administration does not giv advance approval of a manufacturer's compliance with motor vehicle safety standards or regulations, as it is the manufacturer's responsibility under the National Traffic and Motor Vehicle Safety Act to ensure that its vehicles comply with the applicable safety standards. However, my office has reviewed your proposed labels as forwarded with your letter. Based on our understanding of the information which you have provided, your labeling system apparently complies with Standard No. 115.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1318OpenHonorable John B. Conlan, House of Representatives, Washington, DC 20515; Honorable John B. Conlan House of Representatives Washington DC 20515; Dear Mr. Conlan: This will supplement the Bureau of Motor Carrier Safety's reply o October 30, 1973, to your letter of September 21, 1973, to the Interstate Commerce Commission, concerning Mr. William H. Arendell's automatic light-blinking device for truck signaling. The Bureau has referred your letter to us for further reply.; Enclosed for your constituent's information is a copy of Federal Moto Vehicle Safety Standard No. 108, entitled, 'Lamps, Reflective Devices and Associated Equipment.' The effect of paragraph S4.6 of the standard is to prohibit the use of automatic flashing clearance lamps for signaling purposes on vehicles manufactured on or after January 1, 1972. The term 'flash' is defined (paragraph S3) as 'a cycle of activation and deactivation of a lamp by automatic means continuing until stopped either automatically or manually.'; It appears that the device described in your constituent's letter fall within the prohibition of Standard No. 108, and could not be used as original equipment on vehicles. Its use as an aftermarket device would be subject to regulation by the individual States.; I trust the above information will be of interest to Mr. Arendell. Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam5422OpenMr. Lawrence Farhat President/CEO Neon Riders of America, Inc. 521 Copeland Street Jacksonville, FL 32204; Mr. Lawrence Farhat President/CEO Neon Riders of America Inc. 521 Copeland Street Jacksonville FL 32204; Dear Mr. Farhat: We have received your letter of July 5, 1994, wit respect to the legality of neon lighting that your company manufactures for installation on the undercarriage of motor vehicles. You report that some users have been cited by local law enforcement authorities, and state that there has been some confusion as to the legality of this lighting. You ask for our views. This agency establishes the Federal motor vehicle safety standards which must be met from the time a motor vehicle is manufactured up until its sale to its first purchaser for purposes other than resale. Standard No. 108 specifies the lighting equipment that is required when vehicles are manufactured. Lighting equipment that is not required is permissible if it does not impair the effectiveness of the required equipment. The new car dealer is responsible for ensuring that any lighting equipment that it adds before the sale of the vehicle does not impair the effectiveness of lighting equipment that is required by the standard. The initial determination of whether an impairment exists is made by the person responsible for adding the equipment. NHTSA will not question this determination unless it is clearly erroneous. If the lighting equipment is added after the vehicle's sale by a manufacturer, dealer, distributor, or motor vehicle repair business, it is subject to the restriction that it not 'knowingly make inoperative any part' of a lamp that has been installed in accordance with Standard No. 108. Supplementary motor vehicle lighting equipment, whether added before or after initial sale of the vehicle, is subject to the laws of States in which the vehicle is operated, even if the equipment is not prohibited under Federal law. State laws may vary and this is the reason for the confusion. With respect to neon lights, we are aware of aftermarket installations of neon lights on the underside of vehicles that illuminate the pavement below. If such lamps create glare that distracts another motorist from perceiving, for example, the turn signals in use, we would consider that an impairment and a partially making inoperative within the meaning of those terms. We are unable to advise you on State laws regarding the use of neon lights on the underside of vehicles, and suggest that you write for an opinion to the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. NHTSA would like manufacturers of this equipment to be aware that devices such as neon light systems which use high voltage may provide an ignition source for vehicle fires in the event of a crash. The agency would be concerned if undercarriage lighting in use causes or contributes to the severity of post- crash vehicle fires. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam1932OpenMr. W. G. Milby, Staff Engineer, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Staff Engineer Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This is in response to your letter of May 19, 1975, inquiring as to th effect of Federal Motor Vehicle Safety Standard No. 217, *Bus Window Retention and Release*, on a Connecticut law relating to school bus window emergency release.; As you are aware, section 103 (d) of the National Traffic and Moto Vehicle Safety Act of 1966 (15 U.S.C. 1392(d)) provides that no State or political subdivision of a State may promulgate or continue in effect standards applicable to an aspect of motor vehicle or motor vehicle equipment performance which is covered by a Federal motor vehicle safety standard, unless the standards are identical.; Standard No. 217 includes provisions relating to emergency exit forc applications. A differing State specification for emergency release force applications is voided by S103(d) since the Federal standard is intended to cover all aspects of emergency window release performance.; As explained in our November 29, 1974, letter to Mr. Donald L. Gibso (copy enclosed) a Federal standard will preempt any State law that relates to the same aspect of motor vehicle performance yet imposes different requirements. Your responsibility as a manufacturer is to comply with the Federal safety standard. You should note, however, that purchase specifications may be imposed by any person or organization, including a State or municipality, with respect to vehicles purchased for the person or organization's own use. Such specifications are not limited by Federal law, and in the case of governmental bodies are specifically allowed by S103(d), although of course they cannot alter a manufacturer's duty to conform to Federal standards.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam0620OpenMr. O. J. Danker, Irvin Industries Inc., 51 Weaver Street, Greenwich, CT 06830; Mr. O. J. Danker Irvin Industries Inc. 51 Weaver Street Greenwich CT 06830; Dear Mr. Danker: This is in reply to your letter of February 23, 1972, in which you lis information you wish to label on child seats you will manufacture, and ask whether the information as presented will comply with Motor Vehicle Safety Standard No. 213. You state that a label containing the model number, date of manufacture, and the company's name and place of business will be permanently affixed to the product, while a separate legend, containing other information, will be molded on the bottom of the seat in raised letters at least 3/32 inches high.; The labeling scheme you with to use would conform to paragraph S4. ('Labeling') of Standard No. 213, providing, of course, the blank spaces for model number and date of manufacture are appropriately filled in. We would suggest, however, that that part of the molded legend beginning '. . . and there is a minimum of 19 inches vertical clearance between this seating . . .', to the end of that provision be simplified to be more understandable to an ordinary consumer.; We are pleased to be of assistance. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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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.