ID: nht80-3.12

DATE: 06/25/80

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Kansas Department of Transportation

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your June 2, 1980, letter asking whether a school bus that is to be sold to a school district in your State will meet the Federal minimum requirements applicable to gross axle weight ratings (GAWR) and gross vehicle weight ratings (GVWR).

To the best of my knowledge, the Federal government has no minimum specifications for GAWR or GVWR. Certainly, this agency does not specify minimum weight ratings. Our only requirement is that the GAWR and GVWR be appropriate for the size and weight of a vehicle taking into consideration the type of equipment installed on it. From the information that you have provided us, we cannot say that the vehicle in question would or would not comply with that requirement. It is the responsibility of the vehicle manufacturer to certify that its vehicles comply with the Federal safety standards. No school bus manufacturer can sell you a school bus that they know will not comply with the requirements.

ID: aiam5432

"Dear Mr. Turner: This responds to your letter of May 2, 1994 requesting an interpretation of how the term 'daylight opening,' as used in a recent amendment of Standard No. 217, Bus Emergency Exits and Window Retention and Release, would apply to various exits (57 FR 49413, November 2, 1992, and 57 FR 57020, December 2, 1992). Your letter references a March 24, 1994 interpretation letter to Mr. Bob Carver of Wayne Wheeled Vehicles. That letter discussed the term 'daylight opening' as follows: The term 'daylight opening' is defined in the Final Rule as 'the maximum unobstructed opening of an emergency exit when viewed from a direction perpendicular to the plane of the opening.' An obstruction in this context would include any obstacle or object that would block, obscure, or interfere with, in any way, access to that exit when opened. In determining the 'maximum unobstructed opening of an emergency exit,' we would subtract, from the total area of the opening, the area of any portions of the opening that cannot be used for exit purposes as a result of the obstruction. The area measurements would be taken when viewed from a direction perpendicular to the plane of the opening. Your letter states that this interpretation represents a drastic change in what we understood from the wording of the final rule ... and what we were told by Rulemaking. We believed and were told that the definition of daylight opening applied to the exit opening itself and did not involve access to the opening. Access to and obstruction of openings are addressed later in the standard in section S5.4.2 School Bus Emergency Exit Extension. Before answering your specific questions, I would like to respond to these statements. You are correct that S5.4.2 includes requirements related to access to, and obstruction of, exits in that it specifies the minimum opening and the minimum amount of access required for various exits. However, the issue of minimum opening is separate from the issue, addressed in S5.2.3, of the maximum amount of area credited for any opening. Section S5.2.3 specifies the number and type of exits required on school buses. This section states: The area in square centimeters of the unobstructed openings for emergency exit shall collectively amount to at least 432 times the number of designated seating positions in the bus. The amount of emergency exit area credited to an emergency exit is based on the daylight opening of the exit opening. Thus, S5.2.3 specifies the maximum amount of area credited for any opening. An interpretation of the term 'daylight opening' that allowed credit for the exit opening, regardless of obstructions, would be contrary to the plain language of the definition of that term. Giving credit for obstructed areas would also be contrary to the intent of the final rule, which is to increase the area on larger buses which is available for exit in an emergency. With respect to your report of receiving an oral interpretation from agency staff, I would also like to emphasize that, to the extent the public has any questions concerning the meaning of any NHTSA standard or regulation, the only agency interpretations which are authoritative and which therefore can be relied upon by members of the public, such as manufacturers, are those issued in writing by the Chief Counsel. We have reminded agency staff not to make formal, or informal, oral statements that might misinterpreted by manufacturers as official agency guidance on which they may safely rely. Your letter states that the March 24 interpretation 'raises other questions regarding the various school bus emergency exits.' Your questions and the response to each follows. By way of background information, NHTSA does not approve motor vehicles or motor vehicle equipment. The following represents our opinion based on the facts provided in your letter. Rear Emergency Exit Door a. Section S5.4.2.1(a)(1) ... requires unobstructed passage of a rectangular parallelepiped 30 centimeters deep. It is our rationale and interpretation that a seat back or other interior component that lies forward of this 30 centimeter deep parallelepiped is not an obstruction to the rear emergency door and would not result in a reduction of the area credited to the rear emergency door. (See figure 1a) Is this interpretation correct? In the case of a rear emergency exit door, the depth requirement in S5.4.2.1(a)(1) reflects a determination that an interior component outside that limit does not render the exit unusable. Therefore, an interior component outside the area bounded by the transverse vertical plane of the exit opening, the two longitudinal vertical planes tangent to the sides of the exit opening, and the transverse vertical plane parallel to and 30 centimeters away from the plane of the exit opening would not be considered an obstruction for determining the area of 'daylight opening.' b. School buses are typically equipped with 39-inch (99 cm) wide seats. At the rear emergency door, one of the rear seats is typically shifted forward to provide the clearance required by S5.4.2.1(a)(1). The other rear seat is typically allowed to be near or against the rear wall of the bus to fully utilize the available seating floor space and to provide maximum knee clearance. When viewed from the rear, this seat protrudes into the door opening, and according to the (March 24) interpretation ..., the area of the obstruction would not be credited to the exit. Following the logic of the interpretation, the area of the seat itself and the area above the seat could not be credited. We disagree with the logic of the interpretation that door exits are only used by movement along the floor. If the bus is on its side or top, the exit must be used from different approaches. It is therefore our logic and interpretation that only the actual area obstructed (i.e. the area of the seat and the area below the seat) cannot be credited to the exit. For the case in question, the area above the seat can be used in many accident scenarios and therefore can be credited as 'daylight opening.' (See figure 1b) Is this interpretation correct? You are correct that emergency doors will be used by people moving along an interior surface other than the floor if the vehicle is on its side or roof following an accident. As stated in the March 24 interpretation, in determining the amount of daylight opening, you should not credit any area which 'cannot be used for exit purposes.' In the case of the seat illustrated in incoming letter from Wayne, the area over the seat is 6.12 inches by 12.5 inches. However, in reviewing that letter in light of your question, we now agree that the area over the seat may be usable in some accident scenarios. For your exit, neither your letter nor figure 1b provide dimensions of the area over the seat. If the area is large enough to be usable in an accident scenario, that area can be credited towards the daylight opening. c. The rear emergency door on Blue Bird school buses is hinged on the outside, and the top portion of the door is angled forward when the door is closed. When the door is opened and held in the open position by the device required by S5.4.2.1(a)(3)(i), the door protrudes into the exit opening when viewed from a direction perpendicular to the plane of the opening. It is our understanding, based on the interpretation of reference 3, that the protrusion of the door now constitutes an obstruction and the area of the obstruction cannot be credited to the exit area. (See figure 1c) Is this understanding correct? This is correct. Emergency Window Exits The seat backs of school bus seats can protrude into the lower region of side window exit openings. Side window exits when the bus is upright may be used by climbing over the seats. If the bus is on its side or top, the side window exits may be used from different approaches. Since areas of sufficient size above, in front of, and behind a protruding seat back could be used for different parts of the body, (i.e. head, knees, legs) when crawling out a side window exit in different vehicle orientations, it is our logic and interpretation that only the actual area of the seat back in the side window exit opening and the smallest area bounded by the seat back, a horizontal plane tangent to the top of the seat back, and the edges of the exit opening constitute obstructions and cannot be credited to the exit. (See figure 2) Is this interpretation correct? In your illustrations, the area obstructed by the seat back protruding into the window opening clearly cannot be credited to the daylight opening. Whether area above or forward or rearward of the seat back can be credited depends on whether the size of the area is sufficient to be used in exiting the vehicle. Any of these areas which permits passage of the ellipsoid proposed in a December 1, 1993 notice of proposed rulemaking indicates that these areas clearly should be credited (58 FR 63321, see proposed S5.4.2.1(c)). NHTSA proposed this because it believed it reflected the minimum size window which could be used as an exit. If not cut off by obstructions from other unobstructed areas of the daylight opening of the window, as viewed in a plan view, it may be possible that smaller areas should also be credited. In all of the illustrations in figure 2, the seat back extends less than halfway up in the opening. Therefore, it appears that the area above the seat would be credited. We also agree that if the seat protrudes near the front or rear edge of the window opening, it is unlikely that the area between the seat back and the nearest edge of the opening would be usable. However, one of your illustrations shows the seat back protruding near the center of the window opening. In such an instance, it may be possible that the area on each side of the seat back is large enough to be usable. For example, a person might use the window by climbing over the seat, with either their legs straddling the seat, or their head and torso over one side of the seat and their legs over the other. Side Emergency Exit Doors Following the logic presented above regarding the use of emergency exits in different vehicle orientations, we disagree with the interpretation that area A2 (an area bounded by a horizontal line tangent to the top of the seat back, a vertical line tangent to the rearmost portion of the top of the seat, the upper edge of the door opening, and the edge of the door forward of the seat) ... is not usable. In fact even when using the side emergency door when the vehicle is upright, a person would likely lean over the seat back and hold on to the seat, thus using area A2. Figure 3 enclosed is drawn more to scale than the illustration used in (the March 24 interpretation). We suggest the Agency review this illustration, conduct field research by using the exits in real buses, and then reconsider the interpretation ... regarding side emergency doors. We recommend that area A2 be credited as 'daylight opening' for a side emergency door. As explained in our response to question b on rear emergency exit doors, the area above some seats may be large enough to be credited toward the daylight opening. Front Service Door a. The lower portion of the grab handle on many school bus front service doors protrudes into the exit opening when viewed from a direction perpendicular to the plane of the opening. (See figure 4) Based on the (March 24) interpretation ..., we understand that this protrusion now constitutes an obstruction. Is this understanding correct? This is correct. b. The front service door of most school buses leads to a stepwell and steps used to enter the bus. On front engine transit style school buses, the steps are typically angled to the rear and the riser to the first step is just a few inches inboard of the door opening. It is our logic and interpretation that steps in a stepwell do not constitute an obstruction and their presence does not reduce the area credited to the entrance door opening. (See figure 4) Is this interpretation correct? The steps provide the means of using the door, allowing a person to move between the ground and the floor level of the bus. They do not 'block, obscure, or interfere with, in any way, access' of occupants descending to the front service door. Therefore, although they are visible in the doorway when the doorway is viewed in a plan view, the steps are not obstructions within the meaning of the definition of daylight opening. I hope you find this information helpful. If you have any other questions, please contact my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel";

ID: NCC-240112-Goodyear Tire and Rubber Co.

August 8, 2024

Mark Cherveny
Manager, Global Relations, Standards & Compliance The Goodyear Tire & Rubber Company
200 Innovation Way
Akron, OH 44316-0001 

Dear Mr. Cherveny: 

This letter responds to Goodyear Tire & Rubber Company’s “Letter of Interpretation Request for § 571.139 S5.5(c): maximum inflation pressure,” which states that your company has received requests from original equipment vehicle manufacturers to stamp “350 kPa” on “Extra Load” passenger tires. Your request seeks clarification on whether your company is “permitted to stamp an Extra Load passenger tire with a maximum permissible inflation pressure of 350 kPa.” It then asks: “If this is permitted, then would the minimum breaking energy specified in [49 C.F.R.] § 571.109 Table I-C and the test inflation pressures specified in § 571.109 Table II – Test Inflation Pressures … still apply for strength testing?” 

In responding to this request, the National Highway Traffic Safety Administration (NHTSA) notes that the contents of this letter do not have the force and effect of law and are not meant to bind the public in any way. This letter is only intended to provide clarity regarding existing requirements under the law at the time of signature. 

As to your question whether “Extra Load” tires may be labeled as 350 kPa, NHTSA’s Federal Motor Vehicle Safety Standards (FMVSS) have no labeling requirements based on whether a passenger car tire is extra load or standard load. Thus, the FMVSS do not prohibit the proposed labeling on passenger car tires.1 

As to your question about the minimum breaking energy and inflation pressure tests in FMVSS No. 109, the testing requirements in Table I-C and Table II are based on a tire’s maximum inflation pressure and make no reference to whether the tire is labeled as standard load, extra

1 This letter, like your request, focuses solely on the FMVSS. Whether the proposed labeling complies with any other federal or state law or standards is outside the scope of this letter and we take no position on that question.

Page 2
Mr. Mark Cherveny 

load, or XL.2 Thus, passenger car tires with a maximum inflation pressure of 350 kPa are subject to the inflation pressures indicated for 350 kPa tires in the testing requirements set forth in Tables I-C and II. 

We note that your request did not inquire how the testing requirements in FMVSS 139, as opposed to those in FMVSS 109, apply to 350 kPa tires that have been stamped “Extra Load.” Because you did not request an interpretation of the testing standards in FMVSS 139, this letter does not provide such an interpretation. 

Finally, as you note in your letter, FMVSS No. 138—unlike FMVSS 109 and 139—does refer to the maximum inflation pressures for both standard load and extra load tires. The U.S. Tire Manufacturers Association has requested that NHTSA amend FMVSS No. 109 and 139 “to clarify marking and testing based on load classification,” and that it specifically clarify “whether 350 kPa is acceptable as a ‘Maximum Permissible Inflation Pressure’ marking for XL tires.”3 NHTSA is considering that request. However, as they currently stand, the testing requirements in Tables I-C and II of FMVSS 109 make no reference to load classification and are based solely on a tire’s maximum inflation pressure. 

I hope this information is helpful. If you have any further questions, please feel free to contact David Jasinski of my office at (202) 366-2992.

Sincerely,
ADAM RAVIV
Adam Raviv Chief Counsel

Dated: 8/8/24
Ref: Standard No. 109

2 FMVSS No. 109 has never referred to the terms “standard load,” “extra load,” or “reinforced” tires. 58 FR 59227 (Nov. 8, 1993).
3 See Docket No. NHTSA-2019-0011-0017.

ID: aiam1854

Dear Mr. Fredhold: This responds to K-B Axle Company's March 4, 1975, request for guidanc in assisting K-B's customers in meeting their certification responsibilities under Standard No. 121, *Air brake systems*.; Standard No. 121 specifies air brake performance requirements (and som equipment requirements) which newly-manufactured trucks, buses, and trailers must be capable of meeting. For example, the standard specifies that if a truck or bus, in the loaded and unloaded condition, is stopped six times from 60 mph on certain test surfaces, it must be capable of stopping at least once in 258 feet without leaving a 12-foot wide lane and without uncontrolled wheel lockup.; Many manufacturers incorrectly assume that this requirement means that in order to certify that it has this capability, each vehicle produced must actually be tested from 60 mph on a test track. In fact the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1391, et. seq.) specifies the manufacturer's certification responsibility, which is to exercise 'due care' that the vehicle or item of equipment is *capable* of meeting all requirements.; NHTSA has made clear in the past, and has emphasized in it implementation of Standard No. 121, that a manufacturer is free to use whatever method is reasonably calculated to fulfill his responsibility to exercise due care. To cite a simple example, if a safety standard specifies that a certain safety device be no less than 8 inches above the ground, it would not be necessary to measure the height of each safety device on each vehicle produced to assure in the exercise of due care that it complies.; Standard No. 121, of course, establishes more complex performanc requirements, and they would be affected by the addition of your 'tag' or 'pusher' axles. Most final- stage manufacturers and alterers feel confident that they can meet such requirements as minimum air tank volume when they add a third axle. In more complex areas, however, they require some reasonable basis on which to certify, in the exercise of due care, that the vehicle still is capable of stopping within the required distance, and that the brake actuation and release times still meet the minimum performance levels of the standard.; As noted earlier, the standard and our statute do not require roa testing as the basis of certification. NHTSA, in a preamble to Standard No. 121 recognized:; >>>What constitutes due care in a particular case depends on al relevant facts, including such things as the time to elapse before a new effective date, the availability of test equipment, the limitations of current technology, and above all the diligence evidenced by the manufacturer.<<<; Road testing would be one method of exercising due care. You customers, of course, may not have the capability to conduct road testing.; As a supplier of the added component, you are in a good position t develop engineering data on the effect your axle has when added to a 121 vehicle. For example, you could add your axle to a 121 chassis with a representative body and conduct a road test to see that the vehicle with the added axle and gross vehicle weight would still meet the stopping distance requirements. You might also test the actuation and release times on this vehicle to see that the axle addition does not cause non-conformity. This experimentation would permit you to make general statements about the conditions under which your axle could be added to a 121-type chassis without causing non- conformity.; Although retardation force is not a requirement for a vehicle othe than a trailer, you suggest use of dynamometer data as a basis of certification. Such information would be a valid basis of certification if it is shown that a reasonable correlation exists between the retardation forces you specify and the actual ability of the modified truck to stop.; Yours truly, Richard B. Dyson, Assistant Chief Counsel

ID: aiam3795

Dear Mr. Pepe: This responds to your letter concerning Safety Standard No. 209, *Sea Belt Assemblies*. You asked several questions about the requirements applicable to a Type 2 Vehicle Sensitive Emergency Locking Retractor utilizing a tension reducer device. The particular device you are concerned about is, according to your letter, activated by the vehicle door. With the door open the mechanism operates in a high tension mode, with the door closed the mechanism is in a low tension mode.; By way of background information, this agency does not grant approval of vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act it is the responsibility of the manufacturer to certify that its vehicles or equipment comply with applicable requirements. The following represents our opinion based on the facts provided in your letter.; Safety Standard No. 209 specifies requirements concerning minimum an maximum retraction force. Requirements are specified for both initial retraction force and retraction force after a test sequence which includes lengthy retractor cycling. See sections S4.3(j), (k) and S5.2(k).; As you know, retractors have traditionally had only one rather than tw tension modes. Standard No. 209 does not prohibit a design with two tension modes. However, as written, the standard's requirements do not distinguish between tension modes.; We agree with your suggestion that both tension modes should be teste for retraction force effort as specified in the standard. However, we do not agree with your suggestion that the high tension mode should only be tested for minimum retraction force and the low tension mode for maximum retraction force. Instead, because Standard No. 209 does not distinguish between tension modes, we interpret the standard to require that all of its requirements must be met in both tension modes. For example, under section S4.3(j)(6), both tension modes must exert a retractive force within the 0.2 to 1.5 pound range. For testing purposes, of course, a single retractor could only be fully tested for one of the two modes, since testing for both modes would involve twice the amount of cycling required by the standard.; Your letter states that since the high tension mode is used only fo stowing the webbing and is not in operation during normal use, you believe that only cycling tests without lock-ups should be performed in testing. While we appreciate this argument, the standard, as written, does not permit that exception. Section S5.2(k) states in relevant part:; >>>...An emergency-locking retractor or a nonlocking retractor attache to upper torso restraint shall be subjected to 45,000 additional cycles of webbing withdrawal and retraction between 50 and 100 percent extension. The locking mechanism of an emergency locking retractor shall be actuated at least 10,000 times within 50 to 100 percent extension of webbing during the 50,000 cycles....<<<; Since the standard does not distinguish between tension modes, lock-up should be performed in testing for both the low and high tension modes.; As already noted, the retractor in question represents a new desig which was not specifically considered in drafting Standard No. 209. If the standard as written creates problems, the manufacturer may wish to consider submitting a petition for rulemaking to amend the standard to establish special test procedures.; Your letter suggests that there may be a conflict between sectio S7.4.2 of Standard No. 208, *Occupant Crash Protection*, and Standard No. 209's 0.2 pound retraction force requirement (section S4.3(j)). However, section S7.4.2 of Standard No. 208 only applies to automatic belt systems, while section S5.3(j) of Standard No. 209 only applies to active belt systems. Therefore, there can be no conflict.; Sincerely, Frank Berndt, Chief Counsel

ID: aiam4945

Your ref: ST-9015/91 Dear Mr. Suzuki: This responds to your letter o October 16, l991, to the Director, Office of Public and Consumer Affairs, with reference to the 'Safety Shot' lighting device that you have developed. You have enclosed photographs illustrating three types of this device in operation. In brief, the device consists of a center red highmounted stop lamp, immediately flanked by amber lamps that serve as supplementary turn signal/hazard warning signal lamps. Although the photos are not entirely clear, the device appears to consist of segmented compartments in a common housing, with thicker dividers separating the signal and stop functions. Type I incorporates an L.E.D. and is mounted at the top of the rear window. Type II also incorporates an L.E.D. and is mounted at the bottom of the window. Type III is located at the top of the rear window and uses conventional bulbs for its light source. You have been referred to us by Chrysler Corporation. We assume that you approached Chrysler with a view towards having your device accepted as original motor vehicle equipment. You have asked for our views on whether it is possible to use this device in the U.S. market. In the United States, the applicable Federal motor vehicle safety standard for rear lighting is Standard No. 108, Lamps, Reflective Devices, and Associated Equipment. Section S5.4 of Standard No. 108 does not allow a center high-mounted stop lamp to be physically combined with any other lamp or reflective device. Because Safety Shot appears to have a common housing for signalling and stopping functions, the lamps are 'combined' within the meaning of the prohibition. This means that the Safety Shot may not be used as original equipment on motor vehicles, and it may not be offered as a replacement for original equipment center highmounted stop lamps (required on each passenger car manufactured on or after September 1, l985). If you wish to sell the Safety Shot as an accessory in the aftermarket, for passenger cars manufactured before September 1, l985, different considerations apply. Installation of the Safety Shot by a manufacturer, distributor, dealer, or motor vehicle repair business is not permitted if it renders inoperative, in whole or in part, the function of any other rear lighting device. The question, therefore, is whether the effectiveness of the function of any other rear lighting device is compromised by the Safety Shot to the extent that the other device's function is rendered, at the minimum, partially inoperative. We note that original equipment amber signal lamps are not prohibited from flashing when the stop lamps are operating. It would not appear that the addition of the Safety Shot to a passenger car manufactured before September 1, l985, would compromise the signals from the original turn signal and stop lamps in a manner to render them, at least, partially inoperative. However, the Safety Shot is subject to regulation by the individual States of the United States in which it is sold or used. We are unable to advise you on State laws, and suggest that you write for an opinion to American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. Motor vehicles are also required to be manufactured to conform to Standard No. 111, Rearview Mirrors. Under this standard, if installation of the Safety Shot prevents the vehicle from meeting the rearview mirror field of view requirements specified, the manufacturer, distributor, dealer, or motor vehicle repair business installing the Safety Shot must install a rear view mirror on the passenger side of the vehicle (as a practical matter, most vehicles in the U.S. are manufactured with this additional mirror). Sincerely, Paul Jackson Rice Chief Counsel;

ID: aiam3794

Dear Mr. Pepe: This responds to your letter concerning Safety Standard No. 209, *Sea Belt Assemblies*. You asked several questions about the requirements applicable to a Type 2 Vehicle Sensitive Emergency Locking Retractor utilizing a tension reducer device. The particular device you are concerned about is, according to your letter, activated by the vehicle door. With the door open the mechanism operates in a high tension mode, with the door closed the mechanism is in a low tension mode.; By way of background information, this agency does not grant approval of vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act it is the responsibility of the manufacturer to certify that its vehicles or equipment comply with applicable requirements. The following represents our opinion based on the facts provided in your letter.; Safety Standard No. 209 specifies requirements concerning minimum an maximum retraction force. Requirements are specified for both initial retraction force and retraction force after a test sequence which includes lengthy retractor cycling. See sections S4.3(j), (k) and S5.2(k).; As you know, retractors have traditionally had only one rather than tw tension modes. Standard No. 209 does not prohibit a design with two tension modes. However, as written, the standard's requirements do not distinguish between tension modes.; We agree with your suggestion that both tension modes should be teste for retraction force effort as specified in the standard. However, we do not agree with your suggestion that the high tension mode should only be tested for minimum retraction force and low tension mode for maximum retraction force. Instead, because Standard No. 209 does not distinguish between tension modes, we interpret the standard to require that all of its requirements must be met in both tension modes. For example, under section S4.3(j)(6), both tension modes must exert a retractive force within the 0.2 to 1.5 pound range. For testing purposes, of course, a single retractor could only be fully tested for one of the two modes, since testing for both modes would involve twice the amount of cycling required by the standard.; Your letter states that since the high tension mode is used only fo stowing the webbing and not in operation during normal use, you believe that only cycling tests without lock-ups should be performed in testing. While we appreciate this argument, the standard, as written, does not permit that exception. Section S5.2(k) states in relevant part:; >>>...An emergency-locking retractor or a nonlocking retractor attache to upper torso restraint shall be subjected to 45,000 additional cycles of webbing withdrawal and retraction between 50 and 100 percent extension. The locking mechanism of an emergency locking retractor shall be actuated at least 10,000 times within 50 to 100 percent extension of webbing during the 50,000 cycles....<<<; Since the standard does not distinguish between tension modes, lock-up should be performed in testing for both the low and high tension modes.; As already noted, the retractor in question represents a new desig which was not specifically considered in drafting Standard No. 209. If the standard as written creates problems, the manufacturer may wish to consider submitting a petition for rulemaking to amend the standard to establish special test procedures.; Your letter suggests that there may be a conflict between sectio S7.4.2 of Standard No. 208, *Occupant Crash Protection*, and Standard No. 209's 0.2 pound retraction force requirement (section S4.3(j)). However, section S7.4.2 of Standard No. 208 only applies to automatic belt systems, while section S5.3(j) of Standard No. 209 only applies to active belt systems. Therefore, there can be no conflict.; Sincerely, Frank Berndt, Chief Counsel

ID: aiam4097

Dear Ms. Dingledy: This responds to your letter to Steve Kratzke of my staff, askin several questions about the effects of an amendment to the buckle force requirements in Standard No. 213, *Child Restraint Systems* (49 CFR S571.213). Buckles used on child restraints manufactured on or after February 16, 1986, must release with a minimum of 9 pounds force and a maximum of 14 pounds force. Buckles used on child restraints manufactured between January 1, 1981, and February 15, 1986, were required to release with a minimum of 12 pounds applied force and a maximum of 20 pounds applied force. Buckles used on child restraints manufactured before January 1, 1981, were required to release with a maximum of 20 pounds applied force. You asked with which buckle release force requirements replacement buckles provided by your company should comply. Assuming that the replacement buckles are to be installed by you or dealers, distributors, or repair businesses, the answer is that the buckles may, at your option, comply with either the release force requirements applicable to child restraint buckles as of the date of manufacture of the child restraint *or* with the current buckle release force requirements.; Standard No. 213, like all of our safety standards applicable to item of motor vehicle equipment, does not apply to the equipment after its first purchase in good faith for purposes other than resale. This general rule is, however, limited by the provisions of section 108(a)(2)(A) of the Safety act (15 U.S.C. 1397(a)(2)(A)), which specifies: 'No manufacturer, distributor, dealer or motor vehicle repair business shall knowingly render inoperative...any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard....' Please note that these prohibitions do not apply to the child restraint owner rendering inoperative some element of design installed on his or her child restraint. Hence, replacement buckles that are sold to and installed by child restraint owners are not required to comply with the provisions of Standard No. 213.; However, if you as a manufacturer, or any dealers, distributors, o repair businesses were to remove complying buckles from a child restraint and replace them with buckles that did not comply with Standard No. 213, this would violate section 108(a)(2)(A). This result arises because buckles with the specified release force levels were installed on an item of motor vehicle equipment (the child restraint system) in compliance with an applicable Federal motor vehicle safety standard (Standard No. 213). Section 109 of the Safety Act (15 U.S.C. 1398) specifies that each violation of section 108(a)(2)(A) subjects the violator to a potential $1,000 civil penalty.; Assuming that you or your dealers and distributors will be installin the replacement buckles, section 108(a)(2)(A) give you an option of which release force requirements the replacement buckles must meet. In connection with several other standards that have been amended, the National Highway Traffic Safety Administration has stated its opinion that a manufacturer, distributor, dealer, or repair business does *not* knowingly render inoperative an element of design by replacing components installed in satisfaction of a safety standard with other components used in newer items of the same type in satisfaction of the same standard, even if the newer version of the standard imposes less stringent performance requirements. See, for example, the enclosed opinion issued when Standard No. 121, *Air Brake Systems*, was amended, 42 FR 26279, May 23, 1977. In this context, this opinion means that child restraint manufacturers may install replacement buckles that either:; >>>1. comply with the requirements of Standard No. 213 as of the dat the child restraint was manufactured, or; 2. comply with the current requirements of Standard No. 213.<<< If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel

ID: aiam4971

"Dear Dr. French: This responds to your letter inquiring about a recen amendment to Safety Standard No. 111, Rearview Mirrors. (49 CFR 571.111) You explained that your company is developing electronically controlled dimmable (day/night) rearview mirrors for motor vehicles and requested that the agency assess your reading of section S11 of the standard. We are pleased to have this opportunity to interpret our standard for you. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approval of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, the manufacturer is responsible for certifying that its vehicles or equipment comply with applicable standards. The following letter represents our opinion based on the facts presented in your letter. Safety Standard No. 111 specifies requirements for the performance and location of rearview mirrors. Section S11, which was recently amended to better address new mirror designs, specifies requirements for mirror construction. (See 56 FR 58513, November 20, 1991.) The section states in relevant part that: All single reflectance mirrors shall have an average reflectance of at least 35 percent. If a mirror is capable of multiple reflectance levels, the minimum reflectance level in the day mode shall be at least 35 percent and the minimum reflectance level in the night mode shall be at least 4 percent. A multiple reflectance mirror shall either be equipped with a means for the driver to adjust the mirror to a reflectance level of at least 35 percent in the event of electrical failure, or achieve such reflectance level automatically in the event of electrical failure. You asked whether an alternate power source can be used to achieve the specified fail-safe operation (i.e., adjusting the mirror to a reflectance level of at least 35 percent in the event of electrical failure). While your letter did not specify what you meant by 'alternate power source,' we assume that it means an electrical power source other than the one intended to normally operate the mirror. Examples of an alternate electrical power source include solar energy or a self-contained battery system. We interpret the term 'electrical failure,' as used in section S11 of Standard No. 111, to include any type of electrical failure. This would include electrical failure related to an alternate power source as well as electrical failure related to the primary power source. Therefore, unless adjustment of the mirror to a reflectance level of at least 35 percent occurred even in situations where there was electrical failure related to the alternate power source, the alternate electrical source could not be used to provide the fail-safe operation required by section S11. The preamble to the final rule amending Standard No. 111 explained that the agency wanted to assure that multiple reflectance mirrors are capable of providing adequate images at all times during the vehicle's operation, including electrical failure situations where the mirror is unpowered. The agency noted that situations can occur where the mirror would be unpowered even though the vehicle could be operational, citing connector faults and circuit board faults. See 56 FR 58515. To comply with section S11 in situations where a mirror is unpowered as a result of electrical failure, a mirror would either have to default automatically to the high reflectance mode (as in the case of an opposite polarity fail-safe liquid crystal mirror described in the preamble) or be capable of being manually adjusted to the high reflectance mode. We do not have enough information about your proposed mirror to determine whether it would comply with the amendments in the case of electrical failure related to the alternate power source. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure";

ID: aiam5353

"Dear Mr. Schwarz: This responds to your letter to Mr. John Messera o NHTSA, requesting an interpretation of Federal Motor Vehicle Safety Standard No. 116, Motor vehicle brake fluids. Your letter has been referred to my office for a response. As a consumer retrofitting your vehicle with DOT 5 brake fluid, you had several questions concerning the possible effects that an ingredient in the brake fluid might have on elastomers used in brake systems. Your questions are answered below. You mentioned 'seal swelling additives' added to DOT 5 brake fluid, that contact various elastomers in the brake system. Your first question was, when brake fluid manufacturers combine additives with brake fluid, should consumers be concerned with the combined fluids' compatibility with various elastomers used in braking systems? Standard No. 116 defines, at S4. Definitions, brake fluid as a liquid designed for use in a motor vehicle hydraulic brake system where it will contact elastomeric components made of: styrene and butadiene rubber (SBR), ethylene and propylene rubber (EPR), polychlorophene (CR) brake hose inner tube stock, or natural rubber (NR). In order to minimize failures in hydraulic braking systems, Standard No. 116 specifies minimum performance standards for brake fluids. These performance standards include tests for styrene and butadiene rubber cups, the most common type of elastomer in a hydraulic brake system. The brake fluid manufacturer must certify that the brake fluid complies with Standard No. 116. (See S5.2.2(d).) While DOT 5 brake fluid must meet Standard No. 116, the specific ingredients in the fluid are not regulated by the standard. The brake fluid manufacturer is expected to be aware that in addition to SBR, its brake fluid may contact EPR, CR, and NR elastomers in the brake system. Thus, the brake fluid manufacturers must ensure that contact between the fluid and the above stated elastomers would not result in a safety-related defect under the National Traffic and Motor Vehicle Safety Act. Sections 151-159 of the Safety Act concern the recall and remedy of products with defects related to motor vehicle safety. In the event that the brake fluid manufacturer or NHTSA determines that the brake fluid contains a safety related defect, the brake fluid manufacturer would be responsible for notifying purchasers of the defective brake fluid and remedying the problem free of charge. Your second question was whether DOT 5 brake fluid's compliance with Standard No. 116 ensures compatibility with elastomers. The answer is yes, for SBR elastomers. Further, besides Standard No. 116, the brake fluid manufacturer is subject to sections 151-159 of the Safety Act, that were previously discussed. At this time, NHTSA is not aware of safety related defects resulting from other ingredients used with brake fluid. Your third question was whether Standard No. 116 only addresses SBR compatibility with brake fluid. Standard No. 116, at S4, addresses brake fluid that contacts four elastomer types. However, the tests specified in the standard are only of the most commonly used SBR cups. Your fourth question was, if Standard No. 116 only mentions SBR elastomer, would it be advisable to add other elastomers to the specification, or to discuss elastomer compatibility on the brake fluid container? Information discussing the elastomer compatibility of the brake fluid, or other ingredients, may be voluntarily placed on brake fluid containers. Standard No. 116 specifies information that brake fluid containers must carry. However, Standard No. 116 does not prohibit manufacturers from noting on brake fluid containers, compatibility of the silicone brake fluid, or other ingredients, with various elastomers. Finally, you asked what Standard No. 116 specifies as the maximum viscosity for DOT 5 brake fluid, at -40 degrees Fahrenheit. Standard No. 116 specifies, at S5.1.3(c), that the maximum viscosity is 900 centistokes (cSt). I hope that this information is helpful. If you have any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel";