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 |
|---|---|
| search results table | |
ID: aiam0028OpenMr. L.L. Willis, Vice President - Engineering, Thermo King Corporation, 314 West 90th Street, Minneapolis, Minnesota 55420; Mr. L.L. Willis Vice President - Engineering Thermo King Corporation 314 West 90th Street Minneapolis Minnesota 55420; Dear Mr. Willis: Thank you for your letter of July 11, 1967, regarding the applicabilit of the Federal Motor Vehicle Safety Standards to accessories which are purchased for installation after procurement of the car, and in particular, Safety Standard No. 201.; Standard No. 201, 'Occupant Protection in Interior Impact -- Passenge Cars,' applies only to vehicles as originally equipped and does not apply to accessories such as 'after market' auto air conditioners. However, the public would certainly benefit from the maximum degree of conformance that may be feasible on after market installations.; It is sincerely regretted that a written response to your first reques was not received by you and trust that you were not inconvenienced.; Sincerely yours, George C. Nield, Acting Director, Motor Vehicle Safet Performance Service; |
|
ID: aiam2500OpenMr. David F. Berry, Director, Quality Control & Special Products, Birmingham Manufacturing Company, Inc., P.O. Drawer 289, Springville, AL 35146; Mr. David F. Berry Director Quality Control & Special Products Birmingham Manufacturing Company Inc. P.O. Drawer 289 Springville AL 35146; Dear Mr. Berry: This responds to Birmingham Manufacturing Company's June 15, 1976 request to know the certification responsibilities of a manufacturer of low-bed trailers (of the removable goose-neck design) that provides the purchaser with the bed, suspension, and axle portions of the trailer without the gooseneck or the tires and rims. I apologize for our delay in answering.; The portion of the trailer you describe constitutes an 'incomplet vehicle' as that term is described in Part 568 of our regulations (Part 568 -- Vehicles Manufactured in Two or More Stages):; >>>S 568.3 *Definitions*. 'Incomplete vehicle' means an assemblage consisting, as a minimum, o frame and chassis structure, power train, steering system, suspension system, and brake system, to the extent that those systems are to be part of the completed vehicle, that requires further manufacturing operations, other than the addition of readily attachable components, such as mirrors or tire and rim assemblies, or minor finishing operations such as painting, to become a completed vehicle.; << |
|
ID: aiam2150OpenFile; File; On December 10, 1975, I received a telephone call from Mr. Dan Warne of Transportation Manufacturing Corporation in New Mexico (505 347-2011), concerning the scope of Standard No. 119.; Mr. Warner asked whether the standard required vehicles to be equippe with tires conforming to it. I explained that Standard 119 applies only to tires, while vehicles would be the subject of Standard No. 120. I declined to predict the issue date or effective dates of Standard 120, but assured him that the scheme of effective dates would take into account the realities of production and inventories.; Mark Schwimmer |
|
ID: aiam4987OpenMr. Michael Love Manager, Compliance Porsche Cars North America, Inc. P.O. Box 30911 Reno, Nevada 89520-3911; Mr. Michael Love Manager Compliance Porsche Cars North America Inc. P.O. Box 30911 Reno Nevada 89520-3911; Dear Mr. Love: This responds to your letter of April 3, 1992 requesting concurrence by this Office in your interpretation of the requirements of Standard No. 108 for the location of center highmounted stop lamps. Porsche wishes to install a center lamp on the movable spoiler of its 911 Carrera, a configuration previously approved by this Office providing that all photometric and visibility requirements are met. However, S5.3.1.8 of Standard No. 108 requires that 'If the lamp is mounted below the rear window, no portion of the lens shall be lower than 6 inches below the rear window on convertibles, or 3 inches on other passenger cars.' Although Porsche's intended center lamp meets this requirement with the spoiler in the extended position (when the car reaches 45 to 55 mph and slows to 9 to 12 mph), at other times, when the spoiler is lowered, the center lamp would be 7.5 inches below the window on the coupe, and 9.5 inches for the convertible. Nevertheless, you believe that this may be acceptable. You cite an opinion rendered Mazda in which NHTSA did not object to center lamps mounted on tailgates because, as we advised Mazda, the center lamp is a 'supplementary' lamp, and that 'Even if the deck, hatch, or tailgate upon which it is mounted should be open, following drivers may still observe the signals of the primary stop lamps. . .' You further quote NHTSA's frequently repeated advisory that 'Compliance of a vehicle is determined with respect to its normal driving position. . . ,' and argue that Porsche's design 'fulfills the spirit of the height requirements under all conditions' and the height requirement itself 'under a majority of 'normal driving conditions.'' You further argue that even in the down position the triangular relationship between the center lamp and the stop lamps is retained. Finally, you argue that the proposed lamp conforms with NHTSA's philosophy to make Standard No. 108 more performance-oriented 'by fulfilling the photometric requirements at all positions.' I am sorry that we cannot concur in your interpretation. When we judge whether a vehicle meets the location and visibility requirements of Standard No. 108, we determine compliance of the vehicle in what appears to us to be its normal operating or driving position. The fact that the vehicle may not comply under all conditions of operation is, of course, of concern to us, but we try to weigh the realities of vehicle design and usage against the need of the public for safety. In the Mazda interpretation, there was no question that the vehicle as manufactured would comply with the locational requirement for center lamps when the tailgate was closed. The 'normal driving position' of a vehicle with a tailgate is with the tailgate in the closed position, and use of a vehicle with the tailgate not closed is likely to be infrequent compared with its use with the tailgate closed. In another interpretation, rendered years ago, the fact that a vehicle with hydraulic suspension would not meet the minimum height requirements for headlamps with the vehicle at rest was considered a technical noncompliance only because by the time the vehicle was in its normal operating condition (with the engine running and the car ready to move into the stream of traffic), the suspension had raised the vehicle to a height where the headlamps exceeded the minimum height requirements. By contrast, the center lamp on the Carerra will not meet the locational requirements from a state of rest up to a minimum of 45 mph, that is to say, under low-speed urban driving conditions where the center lamp is most likely to achieve its purpose of reducing the frequency and severity of rear end impacts. This, to us, is the 'normal operating position' of the Carerra with respect to the location of the proposed center lamp. I would like to close by pointing out that the agency went to a considerable extent in considering the comments of manufacturers before adopting the requirements of S5.3.1.8, in order to minimize design restrictions consistent with safety. NHTSA proposed three alternative locations, and adopted one that was less restrictive than any of the alternatives. Subsequently, pursuant to petitions for reconsideration by vehicle manufacturers, NHTSA relaxed the location requirements of S5.3.1.8 even further. Sincerely, Paul Jackson Rice Chief Counsel; |
|
ID: aiam0497OpenMr. J. C. Eckhold, Automotive Safety Director, Ford Motor Company, The American Road, Dearborn, MI, 49121; Mr. J. C. Eckhold Automotive Safety Director Ford Motor Company The American Road Dearborn MI 49121; Dear Mr. Eckhold: This is in reply to your letter of November 2, 1971, petitioning t amend Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' and offering comments concerning the notice of proposed rulemaking (Docket No. 3-3, Notice 4), published May 26, 1971 (36 F.R. 9565). You petitioned for the substitution of a 12-inch-per-minute burn rate for the 4-inch-per-minute horizontal burn rate presently specified. For the reasons stated below, your petition is hereby denied.; You base your petition on your belief that the expenditure fo materials that will comply with the 4-inch-per-minute burn rate cannot be justified in terms of the safety benefit achievable. In support of this you state that your analysis shows that the incidence of non-fuel fed fires is extremely low and the probability of injury is extremely remote. You further state that the cost necessary to comply with the standard's requirements as presently issued would involve an increase in vehicle cost from $4 to $10 per vehicle, while you presently have materials which you believe can meet a 12-inch-per-minute burn rate.; The Administration does not agree that there is insufficient data o which to justify the necessary expenditure to obtain a 4-inch-per-minute burn rate. There is ample evidence in the docket that the incidence and severity of non-fuel fires present an unreasonable risk to the public. The Administration has determined that in order for occupants to have sufficient time to escape from a vehicle fire, the material within the vehicle must have a horizontal burn rate that does not exceed 4 inches per minute. Ford has submitted no evidence to show that the 4-inch-per-minute burn rate is excessive or unreasonable from a safety standpoint. In addition, the high toxicity of some vehicle interior materials requires that they burn at a rate that is low enough that vehicle occupants will not be overcome by harmful gases before they can escape from the vehicle. We believe, based upon material found in the docket, that a burn rate of not more than 4 inches per minute is necessary to respond adequately to this need.; You argue further that your suppliers maintain that it would b difficult to meet the 4-inch-per-minute burn rate because of inherent variations in materials, and submit data showing that 'two vinyl coated seat fabrics of the same grain and dark colors' exhibited burn rates of .40 inches per minute and 6.25 inches per minute respectively. The NHTSA understands that the burn rate of some materials may vary. This fact will be taken into account, along with the frequency and extent of any test failures, in assessing whether a manufacturer has exercised due care. It would not be appropriate, however, to respond to the problem of variability by relaxing the overall burn rate. Such an action would probably result simply in manufacturers choosing cheaper and less safe materials.; You also argue that based upon your preliminary findings, aging o materials treated with fire retardants tends to nullify the retardant treatment and destroys the appearance of the material. Other data you submit shows a situation in which the flame retardants did not deteriorate, but the treatment caused deterioration of the material. The evidence available to the NHTSA does not, however, indicate that it is necessary to use flame-retardant treatments that display these undesirable characteristics in order to comply with the standard.; Finally, your petition contains no evidence that the 12-inch-per-minut burn rate that you recommend will allow sufficient escape time in the event of a vehicle fire. Based on the Administration's findings, such a rate would not provide the escape time necessary.; With reference to your comments concerning the proposed amendment t the standard of May 26, 1971, these will be considered as far as is practicable in that rulemaking action.; Sincerely, Robert L. Carter, Acting Associate Administrator, Moto Vehicle Programs; |
|
ID: aiam3311OpenMs. Frances Zinn, President, Flair Interiors, Inc., 55918 St. Road 15 S., Briston, IN 46507; Ms. Frances Zinn President Flair Interiors Inc. 55918 St. Road 15 S. Briston IN 46507; Dear Ms. Zinn: This responds to your recent letter asking whether an assembler o automotive seating would be responsible for defects in the metal frames used in the seats. Apparently, you purchase metal frames from a supplier and then pad and cover them as vehicle seats.; The National Highway Traffic Safety Administration issues safet standards and regulations governing the manufacture of motor vehicles and motor vehicle equipment pursuant to authority of the National Traffic and Motor Vehicle Safety Act, as amended 1974 (15 U.S.C. 1381, *et seq.*.). There are two safety standards directly applicable to vehicle seating, Standard No. 207, *Seating Systems*, and Standard No. 302, *Flammability of Interior Materials*. However, both of these standards apply only to completed vehicles and are, therefore, the responsibility of the vehicle manufacturer, not a supplier such as your company.; In addition to the Federal safety standards, manufacturers of moto vehicles and motor vehicle equipment are responsible for any defects in their products which affect motor vehicle safety. Under 49, Code of Federal Regulations, Part 579.5, the vehicle manufacturer is responsible for any safety-related defect determined to exist in the vehicle or in any item of original equipment, including the original seats. Each manufacturer of an item of replacement equipment is responsible for any safety-related defect in that equipment. Therefore, if you are selling your seats to a vehicle manufacturer, that manufacturer would be responsible for the seats. If, however, you are selling the seats as aftermarket equipment, you would be responsible for their safety. This means you would have to recall the equipment and remedy free of charge any defect relating to motor vehicle safety. If the defect resulted from faulty frames, you could still be held responsible for the seat under Federal law, since you would be considered the manufacturer. You will have to contact a private attorney to determine whether you would then have a right of action against the manufacturer of the seat frames.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam3741OpenMr. Karl-Heinz Ziwica, Manager, Safety & Emission Control Engineering, BMW of North America, Inc., Montvale, New Jersey 07645; Mr. Karl-Heinz Ziwica Manager Safety & Emission Control Engineering BMW of North America Inc. Montvale New Jersey 07645; Dear Mr. Ziwica: This responds to your letter requesting an interpretation of Standar No. 105, *Hydraulic Brake Systems*. Your request was in regard to a type of brake reservoir you are considering producing which would contain common fluid for the brake circuits and the brake hydraulic power assist unit. The issue raised by your letter was whether section S5.4.2 of the standard permits the common fluid to be counted as part of the minimum capacity required for the braking system. As discussed below, the answer to that question is no.; The first sentence of section S5.4.2 states: >>>Reservoirs, whether for master cylinders or other type systems shall have a total minimum capacity equivalent to the fluid displacement resulting when all the wheel cylinders or caliper pistons serviced by the reservoirs move from a new lining, fully retracted position (as adjusted initially to the manufacturer's recommended setting) to a fully worn, fully applied position, as determined in accordance with S7.18(c) of this standard.<<<; As noted by your letter, the agency has previously interpreted thi section with respect to a brake reservoir servicing both the braking system and the clutch. In an October 9, 1981, letter to Toyota, we explained:; >>>This section specifies the total minimum fluid capacity that vehicle's braking system reservoirs must have. That amount is determined by reference to the vehicle's braking system, i.e., by the fluid displacement which results when all the wheel cylinders or caliper pistons serviced by the reservoirs move from a new lining, fully retracted position to a fully worn, fully applied position. The purpose of this requirement is to assure that a vehicle's braking system reservoirs have adequate fluid capacity to service the brakes.<<<; >>>The agency interprets section S5.4.2 to require that the minimu fluid capacity requirements be met by fluid which is solely available to the brakes. If fluid is available to both the brakes and the clutch, some of that fluid is available to both the brakes and the clutch, some of that fluid will be used by the clutch in normal service and thus be unavailable to the brakes. In the event of clutch failure, all of the common fluid may be used by the clutch. Therefore, while standard No. 105 does not prohibit manufacturers from producing master cylinders with reservoirs that have some fluid available to both the braking system and the clutch, none of that common fluid may be counted toward meeting the minimum requirements of section S5.4.2.<<<; This same rationale applies to a reservoir which contains common flui for the brake circuits and brake hydraulic power assist unit. As indicated in our October 1981 letter, the minimum fluid capacity requirements were determined by reference to the vehicle's braking system for the purpose of assuring that a vehicle's braking system reservoirs have adequate fluid capacity to service the brakes, i.e., the wheel cylinders and pistons. More specifically, the requirement for minimum capacity equivalent to the fluid displacement resulting when all the wheel cylinders of clipper pistons serviced by the reservoirs move from a new lining, fully retracted position to a fully worn, fully applied position, was based upon maintaining a sufficient supply of fluid to enable a vehicle to stop even when there was complete brake lining wear-out in the service brake. Put another way, the requirement assures an adequate supply of brake fluid over the lifetime of the brake linings, even if a driver fails to add fluid as part of routine maintenance.; This purpose would not be met if fluid available to both the brak circuits and brake hydraulic power assist unit was counted toward meeting the minimum fluid capacity requirements. Some of the common fluid would be used by the brake hydraulic power assist unit in normal service and thus be unavailable to the brake circuits. Moreover, in some instances of brake hydraulic power assist unit failure (e.g., a failure in the brake hydraulic power assist unit return line), all of the common fluid might be used by that unit.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam4084OpenConfidential; Confidential; Dear Confidential: This responds to your request for this agency's concurrence that proposed mini-van, which would use a front-wheel-drive passenger car platform as its base, would qualify as a light truck under 49 CFR Part 523.5(a)(5). The vehicle would have an airduct lying on top of the floor and running longitudinally rearward from the dash area between the two front seats and then turning outboard to enter the bottom of the 'B' pillar. While the top of the airduct would be above the level floor plane in the area between the front seats and immediately behind the front seats, it would not extend under the second or third seats, which would be removable. The floor would otherwise be flat from the forward most point of installation of those seats to the rear of the automobile's interior.; By way of background information, the National Highway Traffic Safet Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the statutes administered by NHTSA, it is the responsibility of the manufacturer to make any necessary classifications of vehicles and required certifications and to otherwise ensure that its vehicles meet all regulatory requirements. This letter provides the agency's opinion based on the facts stated above. As discussed below, it is our opinion that the proposed mini-van would qualify as a light truck under 49 CFR Part 523.5(a)(5).; Section 523.5 provides in relevant part: >>>(a) A light truck is an automobile other than a passenger automobil which is either designed for off-highway operation, as described in paragraph (b) of this section, or designed to perform at least one of the following functions:; (1) Transport more than 10 persons, (2) Provide temporary living quarters, (3) Transport property on an open bed, (4) Provide greater cargo-carrying than passenger-carrying volume, or (5) Permit expanded use of the automobile for cargo-carrying purpose or other nonpassenger- carrying purposes through the removal of seats by means installed for that purpose by the automobile's manufacturer or with simple tools, such as screwdrivers and wrenches, so as to create a flat, floor level surface extending from the forwardmost point of installation of those seats to the rear of the automobile's interior.<<<; With respect to the location of the airduct, it is necessary in orde to come within section 523.5(a)(5) that the removal of seats creates a flat, floor level, surface extending from the forwardmost point of installation of those seats to the rear of the automobile's interior. Since the airduct would not extend under the removable second or third seats, and since the floor is otherwise flat from the forward most point of installation of those seats to the rear of the automobile's interior, it is the agency's opinion that the vehicle would qualify as a light truck under section 523.5(a)(5).; This does not constitute an opinion as to whether this vehicle would b classified as a passenger car, multipurpose passenger vehicle, or truck for purposes of the safety standards. We note that the classification of the proposed mini-van for purposes of safety standards would be covered by 49 CFR Part 571.3 rather than Part 523. We have enclosed a copy of a letter dated December 1, 1983 which addresses some of the issues involved in making such a classification.; Sincerely, Erika Z. Jones, Chief Counsel |
|
ID: aiam2853OpenMr. Donald Beyer, National Service Manager, Vespa of America Corporation, 355 Valley Drive, Brisbane, CA 94005; Mr. Donald Beyer National Service Manager Vespa of America Corporation 355 Valley Drive Brisbane CA 94005; Dear Mr. Beyer: This is in reply to your letter of July 3, 1978, requesting a interpretation of Motor Vehicle Safety Standard No. 108, specifically, whether turn signal systems installed on mopeds must meet the standard's requirements. One of NHTSA's engineers has informally advised you, in your words, 'that because turn signal units on mopeds are not required devices...they are not required to meet the specific requirements in FMVSS 108 relative to motorcycles as long as they do not affect the operation of the other required equipment.'; We are pleased that Vespa is considering installing turn signal lamp on motor vehicles that S4.1.1.26 excuses from having them. If you wish to install systems that you intend to comply with Standard No. 108 and which for one reason or another fail to do so, it is doubtful that NHTSA would take any action against Vespa since the equipment is clearly optional and added only at a manufacturer's discretion. We would also view as preempted under Section 103(d) of the National Traffic and Motor Vehicle Safety Act any State action either to require turn signal lamps on mopeds or to establish requirements for such were they added at the option of the manufacturer.; I hope this clarifies the matter for you. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
|
ID: aiam1286OpenMr. Jordan J. Pokrinchak, President, Jordan Research Corporation, 179 Rennell Driver, Southport, CT 06490; Mr. Jordan J. Pokrinchak President Jordan Research Corporation 179 Rennell Driver Southport CT 06490; Dear Mr. Pokrinchak: This is in reply to your letter of September 18, 1973 asking for a interpretation of Standard No. 108. You understand that 'the stop lamps must light when applying the automobile brakes and/or when applying the trailer brakes individually.' You tell us of a product that gives a driver 'manual control of the trailer brakes [but] does not light the stop lamps in this mode.'; Paragraph S4.5.4 of Standard No. 108 requires that 'the stop lamps o each vehicle shall be activated upon application of the service brakes.' This section of Standard No. 108 requires that stop lamps on new motor vehicles be wired in this manner. The standard does not apply after the vehicle is purchased, and thus does not prohibit a vehicle owner from modifying the wiring of his vehicle by adding the Electronic Trailer Brake Control. Such an addition, however, might be precluded under State law.; Yours truly, Richard B. Dyson, Assistant 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.