ID: aiam0841

Dear Mr. Stevens: This is in reply to your letter of August 1, 1972, to the attention o Mr. Jerome Palisi of our White Plains, New York Office, concerning certification requirements for a vehicle which you describe and indicate will be used by a college to transport ball teams and school personnel, but will not be equipped with flashing lights or other special school bus equipment. You apparently wish to know whether you must consider this vehicle as a school bus for purposes of certification to Federal requirements.; 'School bus' is defined in the motor vehicle safety standards to mean bus 'designed primarily to carry children to and from school, but not including buses operated by common carriers in urban transportation of school children' (49 CFR 571.3). Based upon the description you provide, the NHTSA would not consider the vehicle you describe to be a school bus. For purposes of certification to Federal requirements (49 CFR Parts 567 and 568), therefore, 'gross vehicle weight rating' should not be computed under the minimum values specified for school buses. In addition, the requirement that vehicle type be inserted on the certification label should be met by inserting, 'BUS.'; This letter should not be construed to mean that the NHTSA takes position as to whether this vehicle need, under State law, conform to requirements for school buses. The State must determine the scope and application of its own laws.; Yours truly, Richard B. Dyson, Assistant Chief Counsel

ID: aiam2867

Dear Mr. Kurre: This responds to your recent letter asking whether Safety Standard No 208 applies to side-facing seats in multipurpose passenger vehicle vans. You also ask to be advised of the criteria to be used for the installation of seat belts in these vehicles.; Safety Standard No. 208, *Occupant Crash Protection*, does require sid facing seats in multipurpose passenger vehicles to comply with one of the options under paragraph S4.2.2, since the side-facing seats in question would be considered designated seating positions. If a manufacturer chooses to install seat belts under one of the options of that paragraph, the seat belt assemblies must comply with Safety Standard No 209, *Seat Belt Assemblies*, and Safety Standard No. 210, *Seat Belt Anchorages*.; Safety Standard No. 210 does exempt side-facing seats from its strengt requirements, but all other requirements of the standard would be applicable. However, we strongly recommend that belt anchorages for side-facing seats be of at least equivalent strength to anchorages for forward and rearward facing seats, since the strength specifications are only minimum performance requirements. Side-facing seats were excepted from the strength requirements specified in the standard because the forces acting on side-facing seats are different from those acting on forward or rearward facing seats and the requirements and procedures were specifically developed for these latter seats.; Please contact this office if you have any further questions. Sincerely, Joseph J. Levin, Jr., Chief Counsel

ID: aiam5279

Dear Mr. Plath: This is in reply to your letter of November 15, 1993 to Taylor Vinson of this Office on trailer conspicuity. You ask for confirmation of several points. Initially, we would like to comment as follows on the 4-point procedure you have outlined: '1) A chassis for purposes of the conspicuity requirement shall be considered to be a trailer.' This is correct. Because the chassis is designed for carrying property and for being towed by a motor vehicle, it is a 'trailer' as defined for purposes of compliance with the Federal motor vehicle safety standards. '2) That the total length of the chassis shall be used in computing the 50 percent coverage of high intensity reflective for each individual side.' This is correct. Under S5.7.1.4.2(a) of Standard No. 108, retroreflective tape 'need not be continuous as long as not less than half of the length of the trailer is covered . . . .' '3) In the case of a 48 foot chassis, the law will thus require a minimum of 24 feet of the approved reflective sheeting to be applied to each side. Further, there shall not be more than 18 inches of either red or silver reflective in a continuous strip and that there shall not be an allowed void of more than 48 inches between modules.' This is partially correct. Under S5.7.1.4.2(a), a minimum of 24 feet of reflective material must be applied to the side of a 48-foot trailer. However, S5.7.1.3(a) requires the colors to be red and white, not red and silver. Further, under S5.7.1.3(b), the permissible lengths of the sheeting are expressed as 'each white or red segment shall have a length of 300 mm +/- 150 mm.' We note that 450 mm is slightly less than 18 inches. Finally, Standard No. 108 does not specify any maximum permissible 'void . . . between modules.' Under S5.7.1.4.2(a), the spaces are to be distributed 'as evenly as practicable.' '4) * * * When the chassis is not loaded with a container, the application of 24 feet per side of a 48 foot chassis of evenly spaced reflective modules would comply with the law as we understand it. It would identify the extreme front and rear portions of the chassis. * * *' This is incorrect. Compliance by an unloaded container chassis with the conspicuity requirements is determined as if the container load were in place. S7.5.1.4.2(a) states that 'at the location chosen for conspicuity treatment , the strip shall not be obscured in whole or in part by other motor vehicle equipment or trailer cargo.' Because the container obscures the gooseneck, the conspicuity treatment mandated by Standard No. 108 cannot identify the extreme front portion of the chassis. Its front termination point will be behind the gooseneck, at a point where it is not obscured by the container. You have correctly stated this with respect to a loaded chassis but it applies to the unloaded chassis as manufactured: '. . . the entire 24 feet (50 per cent of length) shall be applied behind the gooseneck. In general this would mean that the rear 40 foot portion of the chassis would contain the 24 feet of reflective modules. Further we understand that the 50 percent requirement would be satisfied and that additional modules would not have to be applied to the gooseneck.' You conclude that a gooseneck chassis traveling without its container would be in violation of Standard No. 108 if its gooseneck were not marked 'creating a hazard and would violate the requirement stating that a void of no more than four feet is allowable.' You also ask ' i s there a benefit in applying the additional 4 feet of reflective within the rear 40 foot portion of the chassis?' As explained previously, Standard No. 108 does not require marking of the gooseneck of a container chassis, and there is no requirement limiting the spacing between segments of retroreflective material. We believe that the desired conspicuity of the trailer will be maintained by requiring the additional 4 feet of sheeting on the chassis behind the gooseneck when the gooseneck itself will be obscured with the container in place. Standard No. 108 does not prohibit a manufacturer from applying conspicuity treatment to the 8-foot gooseneck of a 48 foot trailer if it wishes to do so, however, the manufacturer is still required to apply not less than 24 feet of material in the 40-foot section behind the gooseneck. We shall be pleased to answer the following four questions you have also raised: '1) Will we need to apply 24 feet of stripping on a 48 foot chassis behind the gooseneck plus an additional 4 feet on the gooseneck?' You will have to apply 24 feet of stripping on the portion of a 48-foot chassis that lies behind the gooseneck, but you are not required to mark the gooseneck. '2) Since a chassis is considered to be treated as a trailer, shouldn't we apply the 24 feet evenly spaced from the extreme rear and front portions of the chassis?' As explained previously, the 24 feet of material is to be applied behind the gooseneck. If you wish to apply evenly spaced conspicuity treatment that includes the gooseneck, you may do so, as long as at least 24 feet of it is behind the gooseneck. '3) Is a tire considered a legal obstruction? If so, can we deduct the distance behind the tire from the 50 percent coverage?' Yes, a tire is 'motor vehicle equipment' within the meaning of S5.7.1.4.2(a) forbidding the obscuring of conspicuity treatment. No, you may not deduct the length of the area obscured by the tire from the 50 per cent coverage. You must include it in the 50 per cent computation. Thus, if a tire would obscure 3 feet of conspicuity material on the side of a 48 foot gooseneck trailer, the manufacturer must apply 24 feet of material in the 37 feet that is behind the gooseneck which is not obscured. We note in passing that the prints submitted for our review by J.Z. Peepas of Selecto-Flash depict conspicuity treatment that is above the top of the tire and apparently not obscured by it. '4) We anticipate that the slide mechanism on an extendable chassis will scrape the reflective film off the chassis. Is the operator then subject to penalties? How will the operator be able to avoid these penalties since they have no control over this process?' You are not required to place conspicuity treatment on the extendable portion of the chassis provided that not less than half of the length of the trailer is covered when the conspicuity treatment is placed elsewhere. In the event that conspicuity treatment is placed on the extendable portion and is damaged when the trailer is in use, the operator will not be subject to any penalties of this agency. Federal regulations governing the use of commercial vehicles in interstate commerce are issued by another agency of the Department of Transportation, the Federal Highway Administration (FHWA). The FHWA requires that vehicles manufactured on or after March 7, 1989, meet the requirements of Standard No. 108 in effect on the date of manufacture of the vehicle (49 CFR 393.11). Therefore, maintenance of the conspicuity treatment on trailers manufactured on or after December 1, 1993, is required by the FHWA. If you wish to write FHWA on this topic, you may address James E. Scapellato, Director, Office of Motor Carrier Standards, FHWA, Room 3107, 400 Seventh Street, SW, Washington, D.C. 20590. The individual states may have regulations in this area as well. We are unable to advise you on State requirements, and suggest that you consult the American Association of Motor Vehicle Administrators, 4600 Wilson Blvd., Arlington, Va. 22203. Sincerely, John Womack Acting Chief Counsel;

ID: 2703y

Mr. W. Marshall Rickert
Motor Vehicle Administrator
Maryland Department of Transportation
6601 Ritchie Highway
Glen Burnie, MD 21062

Dear Mr. Rickert:

Thank you for your letter seeking this agency's opinion as to whether the State of Maryland may amend its motor vehicle regulations to permit the installation of aftermarket tinting on motor vehicle windows, for individuals who may desire this for medical reasons. I am pleased to have this opportunity to describe the legal principles that relate to your question.

The National Highway Traffic Safety Administration ("NHTSA") is responsible for issuing Federal motor vehicle safety standards that impose requirements for specific levels of safety performance for new motor vehicles and motor vehicle equipment. Federal Motor Vehicle Safety Standard No. 205, Glazing Materials (49 CFR 571.205), which has been in effect since 1968, imposes a minimum level of light transmittance of 70 percent in all areas requisite for driving visibility (which includes all windows on passenger cars). The purpose of this requirement is to ensure adequate visibility through the windows, thereby reducing the risk of a motor vehicle crash.

Although Federal motor vehicle safety standards apply directly only to new vehicles and equipment, Federal law also imposes limits on the addition of tinting materials to motor vehicle glazing after vehicles have been purchased by consumers. Pursuant to section 108(a)(2) of the National Traffic and Motor Vehicle Safety Act, 15 U.S.C. 1397(a)(2), manufacturers, distributors, dealers, or motor vehicle repair businesses may not "render inoperative" any equipment or element of design installed in compliance with a Federal safety standard. Thus, those businesses may not install tinting that reduces the light transmittance of windows covered by Standard 205 to a level below the Federal requirement of 70 percent, since that would make the windows "inoperative" within the meaning of Standard 205.

This Federal prohibition is similar to that imposed by section 22-104 of the Maryland Vehicle Law, which provides: A person may not willfully or intentionally remove or alter any safety device or equipment that has been placed on any motor vehicle . . . in compliance with any law, rule, regulation, or requirement of . . . the United States or of this State . . . unless the removal or alteration is permitted by rule or regulation adopted by the [Maryland Motor Vehicle] Administrator.

The "render inoperative" provision of Federal law does not apply to actions by individual vehicle owners. Therefore, each State may regulate the extent to which aftermarket tinting may be applied by vehicle owners to their own vehicles. Thus, although section 22-104 appears to preclude aftermarket tinting by any person if the result would be to reduce the level of light transmittance below 70 percent, Maryland may amend its rules or regulations to permit such tinting by individuals, for medical or any other reasons deemed valid by the State. However, Maryland has no authority to grant any exemptions, including medical exemptions, from the "render inoperative" prohibition of Federal law that applies to commercial entities. Hence, regardless of any provisions of Maryland law, no manufacturer, distributor, dealer, or motor vehicle repair business may legally install window tinting film on a vehicle, unless the vehicle continues to comply with the Federal light transmittance requirements.

In adopting Standard 205, NHTSA determined that a minimum light transmittance of 70 percent is necessary to meet the need for motor vehicle safety. This is the same level of light transmittance contained in the Safety Code of the American National Standards Institute. If, as your letter suggests, Maryland is considering permitting vehicle owners to modify their vehicles such that their windows will have a lower level of light transmittance, we would urge you to carefully consider the safety consequences of such an exemption.

Please let me know if you need any further information on this subject.

Sincerely,

Paul Jackson Rice Chief Counsel

ref:205 d:l0/l5/90

ID: 2878o

Mr. Michael Rose
Technical Secretary for Executive Director
Jamaica Bureau of Standards
6 Winchester Road
Kingston l0
JAMAICA

Dear Mr. Rose:

This responds to your letter, addressed to the Director of the Office of the Federal Register, concerning Federal Motor Vehicle Safety Standard No. l09, New Pneumatic Tires. The National Highway Traffic Safety Administration (NHTSA) is the Federal agency which issued and administers that standard. Your questions are addressed below.

By way of background information, NHTSA issues Federal motor vehicle safety standards under the National Traffic and Motor Vehicle Safety Act, l5 U.S.C. l38l et seq. The term "motor vehicle safety standard" is defined by the Act as "a minimum standard for motor vehicle performance, or motor vehicle equipment performance, which is practicable, which meets the need for motor vehicle safety and which provides objective criteria" (section l02(2)). NHTSA does not grant approvals of motor vehicles or motor vehicle equipment. Instead, section ll4 of the Act requires manufacturers to certify compliance of each motor vehicle and item of equipment with all applicable standards. The Act requires that manufacturers exercise "due care" to ensure that their products conform to each applicable standard (section l08(b)(l)).

I will address your first two questions together. The questions are:

l. In the clause dealing with Test Sample, why are the batch size and sample size not mentioned?

2. Why does the standard make no reference to the frequency of testing.

As indicated above, Standard No. l09 is a minimum performance standard. All tires must be capable of meeting the standard's requirements.

The purpose of the test sample paragraph (S4.2.2.l) in Standard No. l09 is to indicate that a test set for a compliance test consists of three tires. One tire is checked for physical dimensions and is then subjected to resistance to bead unseating and strength, in sequence. The second tire is subjected to the endurance test, and the third tire is subjected to the high speed test.

Paragraph S4.2.2.l is not intended to address the question of how many sets of tires a manufacturer should test as a surveillance procedure during production or what batch size the test sets should be drawn from. A manufacturer is not required to conduct any particular frequency of testing or even to run the actual tests specified by Standard No. l09. Instead, a manufacturer must take whatever steps are necessary to ensure that each of its tires, if tested according to the requirements of the standard, would meet those requirements. (For test purposes, however, any one given tire would only be subjected to one of the three test sequences discussed above.) Since Standard No. l09 includes a number of specific test requirements, it is likely that a manufacturer would find it necessary to do some testing in order to ensure that a tire complied with the standard. For enforcement purposes, NHTSA would test a tire according to the specific test requirements of Standard No. l09.

Your third question is as follows:

3. Why does the standard make no reference to tolerances for tyre concentricity?

NHTSA's standards cover aspects of performance for which the agency has determined there is a safety need. To date, NHTSA has not determined that there is a need for requirements covering tire concentricity tolerances. We note that tire concentricity appears to be primarily an issue of occupant comfort rather than safety.

I hope this information is helpful.

Sincerely,

Erika Z. Jones Chief Counsel

ref:109 d:7/11/88

ID: 3298yy

Mr. S. Suzuki
Managing Director
Suzusho Trading Co.
Center Building No. 601
Fuchucho 1-12-7, Fuchu-shi
Tokyo, Japan

Your ref: ST-9015/91

Dear Mr. Suzuki:

This responds to your letter of 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. l08 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

ref:108 d:1/31/92

ID: nht76-3.10

DATE: 08/19/76

FROM: AUTHOR UNAVAILABLE; Frank A. Berndt; NHTSA

TO: William K. Rosenberry Esq.; Attorney at Law

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of July 14, 1976, to George Shifflett of the Office of Standards Enforcement, on behalf of a client who intends to install a different type of seat, carpeting, and headliner in a pick-up truck, which would then be sold to the general public. You asked whether a fabric supplier must test each fabric lot for flammability before certification to Motor Vehicle Safety Standard No. 302 can be given, and whether your client "may rely on the warranty of a fabric manufacturer that the fabric sold meets the requirements" of Standard No. 302.

You are correct in your understanding that the provisions of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq) apply to your client. His basic responsibility is to ensure that the vehicles he modifies are in compliance with the Federal standards when delivered to dealers for sale to the public. (15 U.S.C. 1397(a)(1)(A)) A temporary noncompliance during modifications is permissible if the vehicle is not used on the public roads while noncompliant (15 U.S.C. 1397(a)(2)(A)). Standards which would appear to be affected by your client's modifications include: Standard No. 207 Seating Systems, No. 208 Occupant Crash Protection, No. 210 Seat Belt Assembly Anchorages and No. 302 Flammability of Interior Materials.

As a person who alters a certified vehicle other than by the addition of readily detachable components, your client is also required to attach his own certification of compliance to each modified truck (49 CFR 567.7). Should a noncompliance be discovered as a result of an alterer's modification, the alterer would be liable for a civil penalty unless he could establish that he did not have actual knowledge of the non-compliance, and that he did not have reason to know in the exercise of due care that the vehicle did not comply (15 U.S.C. 1397(b)(2)).

With respect to Standard No. 302, there is no requirement that a fabric supplier "test each fabric lot for flammability before certification." In point of fact, 49 CFR 571.302 Motor Vehicle Safety Standard No. 302 does not apply to suppliers but only to vehicle manufacturers (or alterers) and it is they who are required to certify compliance with Standard No. 302. Generally, at a minimum, a vehicle manufacturer will require by contract with the supplier that the fabric meets Standard No. 302. In the exercise of "due care" the manufacturer may wish to examine the basis for the supplier's assurance of compliance, and to require periodic testing of the fabric being supplied him. Since there is no requirement that each fabric lot be tested, such testing as is conducted should be sufficient to demonstrate in the event of a noncompliance that the vehicle manufacturer has exercised due care. As to whether your client may rely on the "warranty" of his supplier, it has been our experience that simple reliance is insufficient to establish a "due care" defense. That manufacturer should examine the supplier's test results to insure that the margin of compliance of the test fabric is great enough that production variables do not result in noncompliance. Some manufacturers even conduct their own tests independent of the supplier.

Your client would also be responsible for conducting a notification and remedy campaign (15 U.S.C. 1411 et seq) if a noncompliance or safety-related defect occurs in the truck as a result of the alternations.

I enclose copies of the Act, 49 CFR Part 567, and Standards Nos. 207, 208, 210, and 302 for your information.

ID: nht92-9.33

DATE: January 31, 1992

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: S. Suzuki -- Managing Director, Suzusho Trading Co.

TITLE: Your ref: ST-9015/91

ATTACHMT: Attached to letter dated 10/16/91 from S. Suzuki to Director, Office of Public and Consumer Affairs, NHTSA (OCC 6611)

TEXT:

This responds to your letter of October 16, 1991, 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 1,1985).

If you wish to sell the Safety Shot as an accessory in the aftermarket, for passenger cars manufactured before September 1, 1985, 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, 1985, 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).

ID: nht89-1.75

TYPE: INTERPRETATION-NHTSA

DATE: 04/17/89

FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TO: LEON E. PANETTA -- HOUSE OF REPRESENTATIVES

TITLE: NONE

ATTACHMT: LETTER DATED 02/04/89 FROM LEON E., PANETTA TO ERIKA Z. JONES

TEXT: Dear Mr. Panetta:

This letter responds to your inquiry on behalf of your constituent, Mr. Botelho. You asked whether Federal regulations require mirrors to be placed on the right side of vehicles and whether such mirrors must be convex in nature. Mr. Botelho expressed hi s objection to requiring convex mirrors, because he believes convex mirrors distort images and cause objects to appear further away than they actually are. I am pleased to have this opportunity to explain this requirement and its background for you.

Standard No. 111, Rearview Mirrors (49 CFR @ 571.111, copy enclosed)) establishes performance and location requirements for the rearview mirrors installed in new vehicles. Specifically, a passenger car whose inside rearview mirror does not meet the fiel d of view requirements of section S5.1.1 must have an outside mirror on the passenger side of either unit magnification of a convex mirror. In a September 2, 1982 final rule amending Standard No. 111, the National Highway Traffic Safety Administration ( NHTSA) explained that convex mirrors offer safety benefits by providing an expanded field of view to the rear, thereby reducing the need for the driver to turn around to view the rear directly. On the other hand, some users of convex mirrors that were u sed to the images shown by conventional plane mirrors incorrectly perceived that the object shown in the convex mirror was further to the rear than it actually was. Additionally, some users of convex mirrors experienced double vision, eyestrain, and naus ea. After considering these potential advantages and disadvantages, NHTSA amended Standard No. 111 so that it does not require any vehicle to be equipped with convex mirrors, but it permits the use of convex mirrors on the passenger side of cars and lig ht trucks, provided that the convex mirror meets certain additional requirements.

The additional requirements applicable to convex mirrors on the passenger side of cars and light trucks are:

1. A maximum radius of curvature for the convex mirror. This limits the range of convexities to which drivers will be exposed. It also

ensures that the field of view will be noticeably greater than for a plane mirror.

2. A minimum radius of curvature for the convex mirror. This ensures that the image size in the convex mirror will be adequate and distortion will not be excessive.

3. A stringent maximum permissible variation in the radius of curvature over the surface of the convex mirror. This requirement, which is more stringent than the European requirement in this area, also ensures that convex mirrors will have low distortio n.

4. A warning etched on the convex mirror that objects shown in the mirror are closer than they appear. This requirement ensures that the driver who may not be familiar with convex mirrors will not be misled by the image size of the convex mirror and the apparent distance to the object.

Hence, we agree with Mr. Botelho that the area he has identified are potential problems unique to convex mirrors. However, our standard includes special requirements for convex mirrors to minimize the potential problems identified by Mr. Botelho and oth er potential problems that were identified in research studies of convex mirrors. We are not aware of any data showing that convex mirrors that comply with those special requirements present any unacceptable problems for drivers.

I hope this information is helpful. If you have any further questions or need any additional information on this subject, please let me know.

Sincerely,

ENCLOSURE

ID: nht88-2.34

TYPE: INTERPRETATION-NHTSA

DATE: 05/27/88

FROM: TEVES, ALFRED -- TEVES TECHNICAL SERVICE

TO: ERIKA Z. JONES -- NHTSA CHIEF COUNSEL

TITLE: BRAKE FLUID RESERVOIR DESIGN ACCORDING TO FMVSS 105 REQUEST FOR INTERPRETATION

ATTACHMT: OCTOBER 9, 1981 LETTER FROM BERNDT TO KAWANO, OCTOBER 3, 1988 LETTER FROM JONES TO BURKARD, EBNER, AND TEVES, FEBRUARY 3, 1981 LETTER FROM KAWANO TO BERNDT, JULY 10, 1974 LETTER FROM DYSON TO NAKAJIMA, AND MAY 24, 1988 LETTER FROM TEVES TO GREG ORY

TEXT: during his visit at NHTSA on May 17th, 1988 Mr. Ebner presented our new brake system to your experts.

We request an interpretation of S 5.4.2 (reservoir capacity) and S 5.3.1/b (Fluid level indicator) of FMVSS 105, with respect to the proposed brake fluid reservoir shown in the attachment.

Essential is the existence of an ancillary brake unit in this new brake system. This ancillary brake unit serves the brake circuits 1 and 2 directly.

Compared with a conventional reservoir the proposed brake fluid reservoir's distinctive feature is the exit for the ancillary unit.

This ancillary unit serves the brake circuits 1 and 2. When the brake pedal is released, the used brake fluid will flow back to the reservoir. This unit does not cause any additional fluid volume.

Teves interprets standard 105 S 5.4.2 and S 5.3.1/b) as follows:

1. The total minimum capacity of a reservoir shall be equivalent to the fluid displacement resulting when all the wheel cylinder or caliper pistons serviced by the reservoir move from a new lining, fully retracted position to a fully worn, fully applied position.

2. Reservoir systems utilizing a portion of the reservoir for a common supply to two or more subsystems, individual partial compartments shall each have a minimum volume of fluid equal to at least the volume displaced by the master cylinder piston servi cing the subsystem, during a full stroke of the piston.

3. The total amount of the fluid shall be solely available for the brakes.

4. The ancillary unit shall not use brake fluid for other purposes than for the brake circuits.

5. A drop in the level of brake fluid in any master cylinder reservoir compartment to less then the recommended safe level specified by the manufacturer ot to one-fourth of the fluid capacity of that reservoir compartment, which ever is greater.

The ancillary unit does not diminish the built in safety features of the reservoir. In case of a circuit failure, volume 1 resp. volume 2 remains still available for the brakes and the fluid level indicator lamp gives a warning to the driver.

In case of a fluid leakage in the ancillary unit, the unit is switched off. The fluid level indicator lamp and additional a separate warning lamp gives a warning to the driver. The fluid volumes 1 and 2 remain in the reservoir and are fully usable fo r applying the brakes with the master cylinder.

Accordingly, we believe that the proposed brake fluid reservoir described in this letter and presented to your experts fulfils the requirements S 5.4.2 and S 5.3.1 (b) of FMVSS 105.

We ask that you confirm our interpretation at your earliest convenience.

FMVSS 105, S 5.4.2: V = V[1] + V[2] + V[3] + V[4] V: GREATER OR EQUIVALENT TO FLUID DISPLACEMENT RESULTING WHEN ALL W/C MOVE FROM A NEW LINING POSITION TO A FULLY WORN LINING POSITION. MAX V[4] FLI V[3] V[1] V[2] BRAKE BRAKE ANCILLARY UNIT CIRCUIT 1 CIRCUIT 2 SERVICING BRAKE CIRCUIT 1+2

FMVSS 105, S 5.3.lb V[1] + V[3] >/- 0.25 (V[1] + V[3] + V[4]) V[2] + V[3] >/- 0.25 (V[2] + V[3] + V[4])

V[1] VOL. DISPLACEMENT EQUIVALENT TO A V[2] >/- FULL STROKE OF THE RELATED M/C-PISTON. TEVES MASTER CYLINDER RESERVOIR DESIGN ACCORDING TO FMVSS 105 3-34513-07