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: aiam3462OpenMr. J. Kawano, General Manager, U.S. Representative Office, Toyota Motor Co., Ltd., One Harmon Plaza, Secaucus, NJ 07094; Mr. J. Kawano General Manager U.S. Representative Office Toyota Motor Co. Ltd. One Harmon Plaza Secaucus NJ 07094; This responds to your letter of February 3, 1981, asking two question about Safety Standard No. 105, *Hydraulic Brake Systems*. The questions were asked in regard to a type of brake reservoir you are considering producing which would service both the braking system and the clutch.; The first question is whether an interpretation you have made o section S5.4.2 of the standard is correct. The essential issue to that question is whether hydraulic fluid which is available to the clutch, either for normal use or in the event of clutch failure, can be counted as part of the minimum capacity required by section S5.4.2 for the braking system. The agency interprets the standard to require that the minimum fluid capacity requirements for brake reservoirs be met by fluid which is not available to the clutch, either during normal use or in the event of clutch failure. Thus, as will be explained below, your interpretation is incorrect.; Safety Standard No. 105 establishes requirements for a vehicle' braking system, including minimum capacity requirements for the reservoirs. Neither this standard nor any other Federal motor vehicle safety standard includes requirements for the reservoirs of a vehicle's clutch. While nothing prohibits a manufacturer from producing a master cylinder which service both the vehicles braking system and clutch, the minimum fluid capacity requirements for reservoirs must be met separately for a vehicle's braking system.; 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.<<<; 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 minimum flui capacity requirements for brake reservoirs 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 cylinder with reservoirs that have some fluid available to both the braking system and clutch, non of that common fluid may be counted toward meeting the minimum fluid capacity requirements of section S5.4.2.; Your interpretation of section S5.4.2 is incorrect because it count common fluid toward meeting these requirements. In reference to Figure 1 that you attached with your letter, no fluid above the top of the wall dividing X and Y from Z should be counted toward meeting section S5.4.2's requirements.; We are aware that this interpretation conflicts with our July 10, 1974 interpretation that you attached with your letter and regret any inconvenience. That interpretation indicated that all five designs included in your letter of May 24, 1974, appeared to conform to section S5.4.1, providing that the reservoir capacity requirements of section S5.4.2 were met. That interpretation did not properly consider the requirements of section S5.4.2, as discussed above. It should have indicated that designs (3) and (4) do not comply with Standard No. 105 because they cannot meet section S5.4.2's minimum capacity requirements without counting fluid that is common to the braking system and clutch.; Your letter also asked about which fluid should be counted i determining the minimum warning level specified in section S5.3.1(b). That section refers to a drop in the level of brake fluid in any master cylinder reservoir compartment to less that the recommended safe level specified by the manufacturer or to one-fourth of the fluid capacity of that reservoir compartment, whichever is greater.; The minimum warning level is thus determined by the fluid capacity o each compartment rather than by the total capacity of the reservoir, unless the manufacturer recommends a higher safe level. In reference to Figure 1 that you attached with your letter, the compartments in question are X and Y. Thus, the warning level for compartment X must not be less than 1/4 of the capacity of X. Similarly, the warning level for compartment Y must not be less that 1/4 the capacity of Y. Since there may be safety advantages to higher warning levels, particularly where the capacity of individual compartments is small in relation to the capacity of the reservoir, you may wish to specify a higher warning level such as that indicated in Figure 1, i.e., at a level above the wall separating X form Y.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4555OpenGeorge F. Ball, Esq. Office of the General Counsel General Motors Corporation New Center One Building 3031 West Grand Boulevard P.O. Box 33122 Detroit, MI 48232; George F. Ball Esq. Office of the General Counsel General Motors Corporation New Center One Building 3031 West Grand Boulevard P.O. Box 33122 Detroit MI 48232; "Dear Mr. Ball: This responds to your letter seeking our opinion as t whether a new minivan GM plans to introduce (referred to as the GM 200 minivans in your letter) could be classified as a 'multipurpose passenger vehicle' for the purposes of the Federal Motor Vehicle Safety Standards. In your letter, you indicated GM's belief that this new minivan should be classified as a multipurpose passenger vehicle, because it will be constructed on a truck chassis. Your company has concluded that this minivan will be constructed on a truck chassis for several reasons. First, you state that this chassis has 'truck attributes' that make it more suitable for commercial use than a passenger car chassis would be. The examples of such truck attributes set forth in your letter were an integrated ladder-type frame with full-length longitudinal rails and supporting cross-members, an extended width rear axle, a powertrain certified as complying with the light-duty truck emissions standards, and a flat load floor. Second, you state the chassis is a truck chassis because a cargo van version of this vehicle will be marketed and sold for commercial use. Third, you provided an analysis showing that this minivan will have certain chassis and body characteristics similar to those characteristics of minivans that are now produced and classified as multipurpose passenger vehicles. At the outset, I would like to make clear that the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.) places the responsibility for classifying a particular vehicle in the first instance on its manufacturer. For this reason, NHTSA does not approve or endorse any vehicle classifications before the manufacturer itself has classified a particular vehicle. NHTSA may reexamine the manufacturer's classification in the course of any enforcement actions. We will, however, tentatively state how we believe we would classify this vehicle for the purposes of the safety standards. It is important for GM to be aware that these tentative statements of classification are based entirely on the information presented to the agency by GM, and the tentative classifications may change after NHTSA has had an opportunity to examine the vehicle itself or otherwise acquire additional information about the vehicle. With those caveats, we believe that the GM 200 minivan family could be classified as a multipurpose passenger vehicle for the purposes of the safety standards, because it will be constructed on a truck chassis. The fact that a cargo van version of the GM 200 will be marketed and sold for commercial use is evidence that the common chassis is a truck chassis. Additionally, the front to rear longitudinal side rails and supporting cross-members that are not present on the A-car chassis shows the GM 200 minivan chassis design is more suitable for heavy duty, commercial operations than the A-car chassis. Finally, the characteristics of the GM 200 chassis appear to be similar to the characteristics of other chassis that have been identified as 'truck chassis' by their manufacturers. Accordingly, assuming that your description of the GM 200 chassis is accurate, it appears to us that this minivan is constructed on a truck chassis. The version of your letter to me that has been placed in the public docket has all the information for which you requested confidential treatment deleted from it. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam4398OpenMr. Hiroshi Kato, Assistant Vice President, Technical, MMC Services, Inc., 3000 Town Center, Suite 1960, Southfield, MI 48075; Mr. Hiroshi Kato Assistant Vice President Technical MMC Services Inc. 3000 Town Center Suite 1960 Southfield MI 48075; Dear Mr. Kato: This responds to your letter dated August 3, 1987, in which you sough my confirmation of a previous interpretation I sent to you. The issue is the classification of a new mini-van for the purposes of our safety and bumper standards. I stated in a July 28, 1987 interpretation to your company that, based on the information you had provided, this new mini-van could be classified as a multipurpose passenger vehicle, because it is constructed on a truck chassis. My conclusion that the mini-van's chassis could be considered a truck chassis was based on information you had provided showing that the chassis design and construction was more suitable for heavy duty commercial operation than a conventional passenger car chassis.; In response to this letter, you sent me another letter dated August 3 1987, in which you stated that my previous interpretation may have been based on the erroneous belief that you were going to introduce a cargo version of this mini-van in to the United States, and that this cargo version would have a chassis that was substantially reinforced as compared with the chassis on a passenger version of this mini-van.; My previous interpretation was based on the fact that the mini-van yo will introduce into the United States is built on a truck chassis. My conclusion that the chassis can properly be characterized as a truck chassis was based on the facts that the chassis has a heavier-duty rear suspension and longitudinal members and a 25 percent higher gross vehicle weight rating than the sedan version of this vehicle. Assuming that these understandings are accurate, because nothing in your August 3 letter indicates they were inaccurate, the agency's position was accurately expressed in my July 28, 1987 letter to your company.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3742OpenMr. Karl-Heinz Ziwica, Manager, Safety & Emission Control Engineering, BMW of North America, Inc., Montvale, NJ 07645; Mr. Karl-Heinz Ziwica Manager Safety & Emission Control Engineering BMW of North America Inc. Montvale NJ 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 of 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 minimum flui 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 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 or caliper 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 brakes. 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 |
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ID: aiam3863OpenMr. John B. Walsh, Head, Regulations & Emissions Laboratory, Government Relations Department, U.S Suzuki Motor Corp., 3251 East Imperial Highway, Brea, CA 92621; Mr. John B. Walsh Head Regulations & Emissions Laboratory Government Relations Department U.S Suzuki Motor Corp. 3251 East Imperial Highway Brea CA 92621; Dear Mr. Walsh: This is in reply to your letter of October 31, 1984, to Mr. Vinson o this office, asking for confirmation of a 1972 agency interpretation of Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*.; In pertinent part, Table III of Standard No. 108 requires that, at minimum, a motorcycle be equipped with one taillamp, one stop lamp, and four turn signal lamps. Table IV directs that the stop lamp and taillamp be placed on the vertical centerline, and that the turn signal lamps be placed on each side of the vertical centerline with a minimum edge to edge separation distance of 4 inches between the turn signal lamp 'and tail or stop lamp.' Table IV expressly permits dual stop and taillamps 'symmetrically disposed about the vertical centerline.' No express exception is made to the 4-inch spacing requirement if dual stop or taillamps are installed, raising the question whether the minimum distance must be maintained no matter what the rear lighting configuration may be.; You have called our attention an (sic) interpretation of July 1, 1972 that Motor Vehicle Programs of this agency provided Stanley Electric Company Ltd. In that instance the proposed rear lighting configuration consisted of two combination stop, turn signal, and taillamps placed on either side of the vertical centerline. The agency opined that the minimum separation distance was not applicable to combination lamps when there was 'no tail or stop lamp mounted on the vertical centerline.' You have asked for confirmation that this remains the agency's view.; As you have pointed out Suzuki's proposed design of a unit combinin amber turn signal lamps with red stop and taillamps is similar to current passenger car practice where the minimum distance requirement does not exist. Therefore, this will confirm that the minimum edge to edge separation distance of 4 inches between turn signals and stop and taillamps applies when single stop and taillamps are installed on the vertical centerline, but not when dual stop and taillamps are installed on either side of the centerline.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4091OpenMr. Donald H. Giberson, Assistant Director, Division of Motor Vehicles, Department of Law and Public Safety, State of New Jersey, 26 South Montgomery Street, Trenton, NJ 08666; Mr. Donald H. Giberson Assistant Director Division of Motor Vehicles Department of Law and Public Safety State of New Jersey 26 South Montgomery Street Trenton NJ 08666; Dear Mr. Giberson: This responds to your request for an interpretation of FMVSS No. 121 *Air Brake Systems*. You asked whether vehicles equipped with 'Mini-Max' brakes, produced by Transquip Industries, Inc., comply with the standard. You stated that since the heavy spring is omitted and only a single diaphragm is used, there is no way the brake can function if the diaphragm ruptures. Your question is responded to below. We note that Motor Carrier Regulation 393.40 is administered by the Bureau of Motor Carrier Safety (BMCS) rather than by the National Highway Traffic Safety Administration (NHTSA). We have sent a copy of this correspondence to BMCS in order that they may respond to that part of your request.; By way of background information, NHTSA does not provide approvals o motor vehicles or equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with applicable safety standards. The following represents our opinion based on the facts provided in your letter.; Section S5.6.3 provides in relevant part: >>>The parking brake system shall be capable of achieving the minimu performance specified in either S5.6.1 or S5.6.2 with any single leakage-type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (except failure of a component of a brake chamber housing). . . .<<<; The single diaphragm used in the Mini-Max brake is common to both th service and parking brake systems. As part of the service brake system, it is part of a brake system 'other' than the parking brake system. Therefore, since the diaphragm is not a component of a brake chamber housing, section S5.6.3 requires that a vehicle must be able to achieve the minimum performance specified either in S5.6.1 or S5.6.2 in the event of a diaphragm failure.; We do not have sufficient data to determine whether particular vehicle equipped with Mini-Max brakes would meet the requirements of S5.6.1 or S5.6.2 in the event of a diaphragm failure. The answer to that question could depend on the nature of the particular vehicle. It is possible, of course, that a vehicle could be capable of meeting the requirements of S5.6.1 or S5.6.2 as a result of the braking force provided by the other parking brakes whose diaphragms have not failed.; We note that the California Highway Patrol (CHP) has raised this issu and other issues relating to the compliance and overall safety of Mini-Max brakes in connection with a petition for rulemaking, and that International Transquip has submitted comments on CHP's analysis. We have enclosed for your information a notice granting the CHP petition and an interpretation letter to International Transquip. The CHP and Mini-Max submissions have been placed in the Petitions for Rulemaking (PRM) Docket for FMVSS No. 121. If you desire copies of those submissions, please contact: Docket Section, National Highway Traffic Safety Administration, Room 5109, 400 Seventh Street, S.W., Washington, DC 20590 (202-426-2768).; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam4864OpenGary P. Toth, Esq. General Motors Corporation Legal Staff New Center One Building 3031 West Grand Blvd. P.O. Box 33122 Detroit, MI 48232; Gary P. Toth Esq. General Motors Corporation Legal Staff New Center One Building 3031 West Grand Blvd. P.O. Box 33122 Detroit MI 48232; "Dear Mr. Toth: This responds to your request for an interpretation o how the requirements of Standard No. 209, Seat Belt Assemblies (49 CFR 571.209) would affect some dual-spring retractor designs GM is considering. Your letter said that these dual-spring retractors are designed so that a spring with a lower retraction force is or can be engaged when the safety belt is being worn by an occupant. When the safety belt is removed, a spring with a higher retraction force is engaged to effectively stow the belt webbing. Your letter also said that the retractor for the shoulder belt portion of the lap/shoulder belts on which these designs would be used is an emergency locking retractor (ELR). The minimum and maximum retractor force requirements for ELRs are set forth in S4.3(j)(5) and (6) of Standard No. 209. Those sections specify minimum and maximum retractor force requirements when the retractors 'are tested in accordance with the procedures specified in paragraph S5.2(j).' S5.2(j) specifies that, for the purposes of measuring the retractor forces, the webbing shall be fully extended from the retractor and then retracting the webbing to 75 percent extension plus or minus 2 inches. Your letter stated that your dual-spring retractor designs will comply with the minimum retractor force requirements when tested under the conditions specified in S5.2(j). This is because the higher retraction force will always be engaged under those conditions. It appears that, when the higher retraction force is engaged in these dual-spring retractor designs, the retractors will comply with the minimum retractor force requirements. However, when the lower retraction force is engaged, the retractor force is less than the minimum retractor force requirement. Because these dual-spring retractors comply with the retractor force requirements when tested under the conditions specified in S5.2(j) of Standard No. 209, your company is ready to certify these designs as complying with Standard No. 209. You are, however, concerned with the implications of a February 16, 1984 NHTSA interpretation addressed to Mr. Frank Pepe. In that instance, Mr. Pepe stated that the ELR had two tension modes that were activated by the vehicle door. The subject retractor operated in a high tension mode when the vehicle door was open, and in a lower tension mode when the vehicle door was closed. The agency concluded that, because Standard No. 209 does not distinguish between tension modes, the subject retractors would have to comply with all the requirements of the standard, including the minimum and maximum retraction force requirements, in both tension modes. Your letter asked us to reevaluate the conclusions reached in our February 16, 1984 letter to Mr. Pepe. We believe that the facts presented in your letter are significantly different than those that were presented in the Pepe letter, so the conclusions reached in the Pepe letter are not the same we would reach for your company's dual-spring retractors. In the case of the Pepe letter, the starting point for our analysis of whether the retractors would comply with the minimum and maximum retractor force requirements was the language of S4.3(j) in Standard No. 209, which directed us to the test conditions set forth in S5.2(j) of Standard No. 209. However, the test conditions in S5.2(j) complete extension of the webbing, followed by subsequent retraction to 75 percent extension did not adjust the Pepe retractors to either the high or low tension mode. Some additional action beyond the conditions specified in S5.2(j) had to be taken to select either the high or low tension mode. Since the selection of the high or low tension mode was not specified in S5.2(j) or elsewhere in Standard No. 209, NHTSA concluded that the retractor would have to be certified as complying with the retractor force requirements when adjusted to either the high or low tension mode. The GM retractors present a significantly different situation. According to your letter, the conditions set forth in S5.2(j) will adjust the GM retractors in a way so that the higher retraction force will always be engaged. Assuming this to be the case, no adjustments beyond the conditions specified in S5.2(j) would be necessary to select a tension mode for the retractors. In these circumstances, compliance with the minimum retractor force requirements would be determined only under the conditions specified in S5.2(j). Sincerely, Paul Jackson Rice Chief Counsel"; |
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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 |
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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: aiam4775OpenMr. Jeff Cornell Engineering The Bargman Company 129 Industrial Avenue Coldwater, MI 49036; Mr. Jeff Cornell Engineering The Bargman Company 129 Industrial Avenue Coldwater MI 49036; Dear Mr. Cornell: This is in reply to your letter of July 25, l990, t Taylor Vinson of this Office, asking for clarification of the amendments to Standard No. 108 which were published on May l5 of this year. With reference to section S5.1.1.31, requiring photometric measurement of the entire lamp (and not its individual compartments), you have asked whether this includes the maximums because the preamble to the final rule discussed the requirement only in terms of the minimums. Section S5.1.1.31 refers unqualifiedly to 'measurements' of photometrics, and thus includes maximums as well as minimums. The preamble spoke of minimums only as an example, and was not intended to exclude maximums. I am sorry if this caused some confusion. You have also pointed out that the preamble refers to a minimum luminous lens area of 12 square inches for certain lamps, while the applicable SAE standards that Standard No. 108 incorporates by reference state the minimum as 75 square centimeters, which is only 11.625 square inches. You request a clarification of this point. The appropriate value is 75 square centimeters (11.625 square inches). As a general rule of construction, the text of a standard constitutes the legal requirements which apply. When a value is clearly stated, as in the SAE materials, it takes precedence over an inconsistent value appearing outside the standard, such as in the preamble to the May l5 amendments. The earlier versions of the SAE standards (which the new SAE materials supersede for new motor vehicle equipment) spoke in terms of 12 square inches, and the agency retained this non-metric terminology for purposes of discussing in the preamble the difference between the old and new requirements. Although the SAE could have adopted a value of 77.42 square centimeters (12 square inches) in its new materials, it chose to round the value off to 75 square centimeters, thereby reducing its previously specified minimum luminous lens area by .375 square inch. With respect to another concern, you have presented the hypothetical of the use 'in a molded bumper or fiberglass cap' of three identical single compartment stop lamps per side, none of whose individual luminous lens areas meets the 75 square centimeter requirement, but which, in combination, would exceed it. You have asked whether this would comply with the new requirements. Our answer is no. On May l5, Standard No. 108 was also amended to add a definition for 'Multiple lamp arrangement.'(S3). This is 'an array of two or more separate lamps on each side of the vehicle which operate together to give a signal.' Paragraph 5.3.2 of the newly-incorporated SAE Standard J1398 MAY85 for stop lamps on wide vehicles states in pertinent part that 'The functional lighted lens area of a single lamp . . . and each lamp of a multiple lamp arrangement shall be at least 75 square centimeters.' The configuration you describe is a 'multiple lamp arrangement' and each lamp in the array is subject to the minimum specified requirement. You further ask, if 'the vendor making these lights mounts the individual lights in a molded housing', whether this would create a 'multiple compartment lamp', and if so, 'then how is it different if it is installed into a molded bumper or fiberglass cap.' The definition of 'Multiple compartment lamp' adopted on May 15 states that it is 'a device which gives its indication by two or more separately lighted areas which are joined by one or more common parts, such as a housing or lens.' Multiple lamps cannot be combined to create a 'multiple compartment lamp'. If the individual lamps are mounted in a molded housing, they remain 'an array of two or more separate lamps on the same side of the vehicle which operate together to give a signal', that is to say, a 'multiple lamp arrangement.' The 'lighted areas' of a 'multiple compartment lamp' are something less than a complete lamp, but, when joined by common parts become a single lamp. The configuration you describe is not a 'multiple compartment lamp.' If you have any further questions, we shall be pleased to answer them. Sincerely, Paul Jackson Rice 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
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