ID: 17490.ztv

Tadashi Suzuki, Manager
Automotive Equipment
Legal & Homologation Sect.
Stanley Electric Co., Ltd.
2-9-13, Nakameguro, Meguro-ku
Tokyo 153,
Japan

Re: Vehicle Headlamp Aiming Device

Dear Mr. Suzuki:

This is in response to your letter of March 6, 1998, asking for confirmation of the acceptability of Stanley's aiming adjustment mechanism under Standard No. 108.

This mechanism is intended for headlamps that will be used on vehicles manufactured on and after September 1, 1998. On all such vehicles, each headlamp equipped with a vehicle headlamp aiming device (VHAD) must be manufactured with its calibration permanently fixed by its manufacturer (S7.8.5.2(c)).

The Stanley headlighting system consists of two headlamps, each equipped with two single-filament light sources. The headlamp is designed to be visually/optically aimable. Reflectors for both bulbs are integrally molded so that one aiming mechanism is sufficient to aim both the lower and upper beams. The headlamp system will be installed on a vehicle with an automatic leveling system which has a range of vertical movement of +/-2.5 degrees.

The headlamps in question that are intended for use on vehicles manufactured before September 1, 1998, are equipped with two aiming bolts to facilitate manual aiming. Bolt A is used for horizontal aiming. Both Bolts A and B are used for vertical aiming. From the drawings on Attachment 2 to your letter, it is evident that any independent movement of Bolt B also affects horizontal aim because it causes rotation around an axis that is other than horizontal. You have informed us that, with respect to vehicles manufactured on and after September 1, 1998, Stanley intends to provide headlamps that comply with S7.8.5.2(c) either by removing the VHAD from Bolt A or by permanently fixing its calibration (Stanley has not yet made its choice). With either choice, "the range of vertical adjustment by bolt B with less than 0.76 degree horizontal aim deviation is +/- 1 degree." You explain that "the automatic leveling system supplements the manual aiming system and covers the maximum variation of vehicle pitch, which depends on loading and the actual movement during driving and may exceed +/- 1 degree." We want to point out that if only Bolt B is used to adjust the lamp vertically by more than 1 degree, horizontal misaim will exceed 0.76 degree. This will result in a noncompliance, unless, pursuant to S7.8.5.2(b)(3), an advisory label is placed adjacent to the mechanism and instructions to be inserted in the vehicle operator's manual indicating that both Bolts A and B must be used to adjust vertical aim.

Alternatively, Stanley could retain the horizontal VHAD function and permanently fix its calibration. Paragraph S7.8.5.3(b) states that "there shall be no adjustment of horizontal aim unless the headlamp is equipped with a horizontal VHAD." Since the movement of either Bolt A or Bolt B affects the horizontal aim, it is not possible to use the fixed horizontal aim approach of S7.8.5.3(b) while allowing independent movements of Bolts A and B for vertical aim. Therefore, use of this alternative would require the addition of a second VHAD. In Stanley's design, finding the factory setting for horizontal aim depends on the relationship between the settings of two adjustment bolts rather than, as in the usual design, the absolute position of a single independent adjustment bolt. It would be necessary to equip both bolts with horizontal VHAD indicators with a fixed calibration so that the factory horizontal aim could be restored during the process of vertical aim adjustment. For example, having the VHAD indicators of each bolt read the same number could indicate the proper relationship for factory horizontal aim. We believe that this interpretation is consistent with the interpretation provided you on this subject by Transport Canada.

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:108
d.6/30/98

ID: 17491.ztv

Robert B. Nicholas, Esq.
McDermott, Will & Emery
600 13th Street, N.W.
Washington, DC 20005-3096

Dear Mr. Nicholas:

This is in reply to your letter of March 6, 1998, asking for confirmation of your interpretation that an electric-powered scooter, manufactured by your client EMPower Corporation, is not a "motor vehicle" within the meaning of 49 U.S.C. 30102(a)(6).

You have described the scooter as a three-wheeled vehicle with a maximum speed of 15 miles per hour. It has "a platform, no seat and is designed to be driven standing up. The scooter's steering mechanism, composed of handlebars, steering column, fork and wheel, is collapsible and folds toward the platform for easy storage and portability."

You have cited interpretations of the agency in which other, similar vehicles were held not to be "motor vehicles." These exempted vehicles feature lack of a seat and the ability to be folded to be portable (see letters of June 12, 1995, to Andrew Grubb, re "California Go-Ped," letter of October 5, 1993, to Bernhard Peer, re "TWIP" electric scooter; and letter of April 1, 1991, to Mark. A Pacheco re "Walk Machine").

We concur with your conclusion that these interpretations are relevant to the EMPower electric scooter, as you have described it, and that, accordingly, the EMPower electric scooter is not a "motor vehicle" under 49 U.S.C. 30102(a)(6).

If you have any questions, you may call Taylor Vinson of this Office (202-366-5263).

Sincerely,
John Womack
Acting Chief Counsel
ref:VSA
d.5/22/98

ID: 17494.ztv

Mr. Keith Reichow
26409 148th Ave. S.E.
Kent, WA 98042-8142

Dear Mr. Reichow:

This is in reply to your letter of March 5, 1998, with respect to your planned importation of an automobile body. You have asked for a "letter that can be presented to U.S. Customs that would assist in clearing this hardware."

We are pleased to provide an interpretation to you. You intend to import "the frame with axles and suspension attached." In addition, "the aluminum body skin and fenders would be in place and the dashboard would be equipped with some instruments. The radiator, brake, clutch and gas pedals would also be mounted."

None of the Federal motor vehicle safety standards apply to any of these items of equipment. Accordingly, it is permissible for you to import the body by completing the box titled "Description Of Merchandise If Motor Vehicle Equipment" on the HS-7 Declaration Form which you may be required to execute, and, under it, checking Box 1 which states in pertinent part that "the equipment item was manufactured on a date when no applicable Federal Motor Vehicle Safety or Theft Prevention Standard was in effect." You may attach a copy of this letter to the form to facilitate entry.

Even though the assembled vehicle will be a replica of an early 1960s Lotus 7, it must comply upon manufacture with all Federal motor vehicle safety standards of 49 CFR Part 571 that apply to passenger cars manufactured in 1998, even if they are not necessarily compatible with a 35-year old design. The vehicle would have to meet the bumper standard as well (49 CFR Part 581).

If you have any questions, you may call Taylor Vinson of this Office (202-366-5263).

Sincerely,
John Womack
Acting Chief Counsel
ref:591
d.5/22/98

ID: 17495.drn

Ms. Leigh Morrison
Project Engineer
Irvin Automotive
2500 Takata Drive
Auburn Hills, MI 48326

Dear Ms. Morrison:

This responds to your letter asking whether any Federal motor vehicle safety standards (FMVSSs) apply to vanity mirrors in motor vehicle sun visors. In a telephone conversation with Dorothy Nakama of my staff, you explained that Irvin Automotive places vanity mirrors into sun visors, and sells the assemblage to motor vehicle manufacturers that then install the visors into motor vehicles.

Some background information may be helpful. The National Highway Traffic Safety Administration (NHTSA) is authorized to issue FMVSSs for new motor vehicles and new items of motor vehicle equipment. Unlike the practice in many countries, NHTSA does not provide approvals of motor vehicles or motor vehicle equipment. Instead, manufacturers are required to certify that their vehicles and equipment meet applicable standards.

Standard No. 201, Occupant Protection in Interior Impact, applies to "passenger cars and to multipurpose passenger vehicles, trucks, and buses with a GVWR of 4,536 kilograms or less." In an interpretation letter of July 3, 1997 to Daewoo Motor Company (copy enclosed), the agency stated that Daewoo's vanity mirror must be installed in a fashion that assures that the sun visor meets Standard No. 201. The letter to Daewoo referred to a provision, S3.4.2, that applied to sun visors. Effective May 8, 1997, that provision is S5.4.2, and states:

Each sun visor mounting shall present no rigid material edge radius of less than 3.2 mm that is statically contactable by a spherical 165 mm diameter head form.

The letter to Daewoo also stated that Daewoo's vanity mirror would not have to meet Standard No. 205, Glazing Materials.

You ask whether Standard No. 107, Reflecting Surfaces, applies to vanity mirrors. The answer is no. Effective May 6, 1996, NHTSA rescinded Standard No. 107. Even when it was in effect, Standard No. 107 did not apply to vanity mirrors.

NHTSA has established Standard No. 111, Rearview Mirrors. In an interpretation letter dated October 21, 1971 to Mr. James V. Blethen (copy enclosed), NHTSA stated that Standard No. 111 "does not apply to mirrors per se but specifies requirements that must be met by rearview mirrors mounted in new passenger cars and multipurpose passenger vehicles." Since your vanity mirrors in sun visors are presumably not meant to be used as rearview mirrors, Standard No. 111 would not apply to your product.

NHTSA's statute also addresses defects that are related to motor vehicle safety. If a manufacturer or NHTSA determines that a safety-related defect exists, the manufacturer must notify purchasers of its product and remedy the problem free of charge. (This responsibility is borne by the vehicle manufacturer in cases in which your sun visors are installed on a new vehicle by or with the express authorization of that vehicle manufacturer.) Any manufacturer which fails to provide timely notification of or remedy for a defect may be subject to a civil penalty of up to $1,100 per violation.

I hope this information is helpful. If you have any further questions, please feel free to contact Dorothy Nakama at this address or by telephone at (202) 366-2992.

Sincerely,
John Womack
Acting Chief Counsel
Enclosures
ref:107#111#201#205
d.4/29/98

ID: 17497.ztv

Herr Tilman Spingler
Robert Bosch GmbH
FAX 9-011-49-7121-35-1792

Dear Herr Spingler:

This is in reply to your fax of March 12, 1998, commenting on our letter to you of March 10 with respect to the visual/optical headlamp aiming provisions of Federal Motor Vehicle Safety Standard No. 108.

In response to your question, our letter advised that it would not be permissible to install on new vehicles a mixed headlighting system in which a headlamp on one side of the vehicle would have a VHAD for vertical aim and on the opposite side a visually aimable headlamp. We also advised that the VHAD appeared to allow for vertical aim only and did not include a horizontal aiming feature. You comment that it was not the intent to have a headlamp with only a vertical VHAD but "to replace the vertical VHAD (bubble level) by means which allow optical/visual aim and to leave the horizontal VHAD as it is." We understand from your remark that both headlamps would have a horizontal VHAD and that one would have a vertical VHAD as well while the other would substitute for the vertical VHAD a means allowing optical/visual aim. This clarification, then, moots our previous comment.

You have also commented that "mixed installation should only be permitted in the case of replacement of a damaged headlamp as indicated in my FAX of 1/14/98," and asked whether our advice that the headlamps on both sides of a new vehicle have to be identical "really only applicable for new vehicles."

We do not seem to have received your FAX of January 14, 1998, in which you indicated that your question pertained to replacement headlamps rather than original equipment. While the prohibition against mixed headlamp aiming systems that was the subject of the March 10 interpretation applies only to new vehicles, the agency is concerned that the ability to correctly aim all headlamps on a vehicle could be lost as a result of certain mixes of replacement headlamps. Accordingly, the agency expects to propose shortly rulemaking that will address this issue.

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:108
d.6/3/98

ID: 17501.wkm

The Honorable Paul D. Coverdell
United States Senate
100 Colony Square, Suite 300
1175 Peachtree Street, NE
Atlanta, GA 30361

ATTN: Brice Willis

Dear Senator Coverdell:

This responds to your letter to Mr. Steve O. Palmer, the Department's Deputy Assistant Secretary for Governmental Affairs, which was referred to this agency for reply.

Your letter forwarded a letter dated January 23, 1998, from Mr. Jimmie D. Gowen, Jr., President, Big John Trailers, Folkston, GA. Mr. Gowen's letter enclosed copies of letters to The Honorable Saxby Chambliss, U. S. House of Representatives, and to Ms. Heidi Coleman, Assistant Chief Counsel for General Law in this office. Mr. Gowen stated in his letter to you that his company produces self-propelled loader/crane carriers that are equipped with early model used truck air brake axles that are not designed for antilock brake system (ABS) applications as now required by Federal Motor Vehicle Safety Standard (Standard) No. 121, Air brake systems. He stated that such vehicles are utilized primarily off-road in logging operations, although they are capable of being towed between job sites. He stated that being required to comply with the ABS requirements would result in his company's having to eliminate the vehicle from the company's product line. He therefore asked your assistance in bringing the matter to the attention of the proper authorities.

For your information, Mr. Gowen wrote to this agency on January 26, 1998, and submitted additional information to us on March 12, 1998. He asked whether knuckle boom loader trailers and self-propelled loader carriers that his company produces are required to comply with the ABS requirements of Standard 121. We replied that they are not subject to the ABS requirements because those particular vehicles do not meet the statutory definition of "motor vehicle."⁽¹⁾ Therefore, they need not comply with the Federal motor vehicle safety standards, in particular the ABS requirements of Standard 121. A copy of our response to Mr. Gowen is enclosed for your information.

I hope this information is helpful to you. Please let me know if I can be of any further assistance in this matter.

Sincerely,
John Womack
Acting Chief Counsel
Enclosure
ref: 121#VSA
d.4/23/98

1. "'[M]otor vehicle' means a vehicle driven or drawn by mechanical power and manufactured primarily for use on public streets, roads, and highways, but does not include a vehicle operated only on a rail line." 49 U.S.C. 30102(a)(6).

ID: 17506-r.wkm

Mr. Chris Cardwell
Manufacturing Engineer
McKechnie Vehicle Components
Fluid Handling Division
Post Office Box 537
Newberry, SC 27108

Dear Mr. Cardwell:

Please pardon the delay in responding to your letter to this office in which you ask for an "official ruling" as to whether the plastic tubing you produce is subject to Federal Motor Vehicle Safety Standard (Standard) No. 106, Brake hoses, or any other Federal motor vehicle safety standard.

You state that your company intends to produce plastic tubing for use in the model year 2000 Ford Escort. The tubing will be utilized as low-pressure brake fluid return lines running from the clutch to the brake fluid reservoir and from the fluid reservoir to the brake master cylinder. The fluid in these lines will not be under pressure since the reservoir is open to the atmosphere. You feel that for that reason, these tubes are not subject to Standard No. 106.

Standard No. 106 applies to new motor vehicles and to "hydraulic, air, and vacuum brake hose, brake hose assemblies, and brake hose end fittings...." The term "brake hose" is defined in pertinent part in S4 of the standard as:

[A] flexible conduit, other than a vacuum tubing connector, manufactured for use in a brake system to transmit or contain the fluid pressure or vacuum used to apply force to a vehicle's brakes.

Hoses are excepted from Standard 106 if they do not transmit or contain the brake fluid pressure or vacuum used to apply force to a vehicle's brakes. To determine whether the hoses you produce are excluded from the standard, you must determine whether a failure of your hose would result in a loss of pressure in the brake system. If this would be the case, the hoses transmit or contain the pressure used to apply force to the vehicle's brakes and therefore would have to comply with the standard. (See NHTSA's August 3, 1984 letter to Eaton Corporation, copy enclosed, concerning small diameter hoses used on air brake equipped trucks.) Failure of a conduit that transmits or contains the pressure used to apply force to a vehicle's brakes would either immediately or eventually affect the vehicle's braking performance. It is important, therefore, for such hoses to meet the performance requirements of Standard 106, to reduce the likelihood of failure in service. If you use a check valve or some other device to prevent loss of pressure, then the hose would not contain or transmit the pressure and would not be required to comply with Standard 106.

I hope this information is helpful to you.

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosure
ref:106
d.6/5/98

ID: 17513mer.b-i

Mr. Daniel J. Selke
Manager, Safety Engineering
Mercedes-Benz of North America, Inc.
One Mercedes Drive
P.O. Box 350
Montvale, NJ 07645-0350

Dear Mr. Selke:

This responds to your letter to the National Highway Traffic Safety Administration (NHTSA) asking about the test requirements in Federal Motor Vehicle Safety Standard No. 213, "Child Restraint Systems," for a child restraint system you plan to sell. You believe that the system is a "built-in" child restraint system under Standard 213 and ask for confirmation that the restraint will not be tested in "misuse" configurations, i.e., installed on the testing apparatus in ways contrary to Mercedes-Benz's instructions for using the restraint. As explained below, we have carefully considered your suggested interpretation and regret that we cannot confirm it.

You describe the restraint as follows:

The system is composed of two parts; an integrated booster cushion and an add-on impact shield. The booster cushion is operated by a push-button. When activated, a portion of the rear seat of a vehicle equipped with the system raises to form the booster cushion. . . .[Daimler-Benz AG's (DBAG's)] integrated child restraint system is a progressive system designed for use with children as they grow older. The impact shield is designed for use in conjunction with the booster seat for children who weigh 9 to 18 kg (20 to 40 lbs.). The impact shield is secured directly in front of the child by the lap and shoulder belt with the "legs" of the shield stabilized by being placed on both sides of the booster cushion. Without the presence of the booster cushion, the "legs" of the impact shield would collapse making use of the shield alone unrealistic. The design of the impact shield acts to secure the child's torso and to keep the child's legs fixed. Children who weigh 18 to 36 kg. (40 to 80 lbs.) only need the booster seat and standard lap and shoulder belt to be properly secured. Children who weigh more than 36 kg (80 lbs.) may use the conventional lap and shoulder belts.

For convenience, we have depicted these recommended weight ranges and restraint configurations in the following table:

DBAG'S RECOMMENDATIONS

Your specific questions concern how NHTSA would test the restraint. You want us to confirm that when the restraint is tested in the configuration intended for children under 40 lb., the agency would test the system using both the booster and the shield with the vehicle's lap and shoulder belt. You also ask us to confirm that when the restraint is tested in the configuration intended for children greater than 40 lb., the booster would be used with the vehicle's lap and shoulder belt. You would like us to concur that "At no time, would testing of the system be required that involved use of the shield without the booster."

We agree with some of your statements but do not agree with others. We agree that the shield would not be tested without the booster. Standard 213 defines a "child restraint system" as "any device except Type I or Type II seat belts, designed for use in a motor vehicle or aircraft to restrain, seat, or position children who weigh 50 pounds or less." An impact shield is designed "to restrain. . . children." The standard also defines an "add-on" child restraint system as "any portable child restraint system." A portable impact shield that is sold to consumers without any other accompanying parts would be an add-on child restraint system and, obviously, would be tested to Standard 213's requirements without any other part. Your shield, however, is merely a component of a child restraint system and is not intended to be used separately from the other parts of the restraint system. The shield cannot even support itself on its "legs" without the booster cushion. Because of these factors, we do not consider your impact shield to be an add-on child restraint system. The shield itself would not be tested to the requirements of Standard 213 without the booster.

However, there is a question of whether your restraint system (booster cushion with impact shield) is a "built-in child restraint system" under Standard 213 (S4). Configured in the mode used to restrain children under 40 lb., the restraint does not meet the standard's definition of a "built-in child restraint system."

The standard defines "built-in child restraint system" as "a child restraint system that is designed to be an integral part of and permanently installed in a motor vehicle." (Emphasis added.) NHTSA has used the term "integral" in the context of Standard 213 to mean "formed as a unit with another part." See, e.g., April 29, 1980 letter to Mr. Koziatek (copy enclosed). The add-on impact shield would not be formed as a unit with the motor vehicle. Also, the add-on shield would not be "permanently installed" in the vehicle. Because of these factors, we would not consider the add-on shield to be part of the built-in child restraint system. Accordingly, we would not use the shield when testing the restraint in Standard 213 compliance tests.

This means that the booster would have to meet Standard 213's requirements when configured so as to consist of the cushion alone with the lap and shoulder belts, without the shield, and when tested with each of the appropriate test dummies specified in the standard. The standard specifies that child restraints recommended for children weighing 20 to 40 lb. are tested with a dummy representing a 3-year-old child. Because the add-on shield is not part of the built-in system, it would not be used in the compliance test using the 3-year-old dummy, notwithstanding any instructions you might provide to consumers to use the shield. Add-on, nonpermanent components can be lost or misplaced and may not be accessible when the restraint has to be used.

Standard 213 does not prohibit you from voluntarily providing add-on pieces to possibly improve the performance of your built-in restraint. However, as stated in the preceding paragraph, the restraint must provide a minimum level of safety and meet Standard 213's requirements without use of the add-on components, to ensure that the restraint will provide adequate protection in the event the add-on components are not used. Of course, if Mercedes-Benz redesigned this seat to assure that the shield was "integral" and "permanently installed," these considerations would not apply.

With respect to the restraint's configuration for older children, Standard 213 also specifies that a test dummy representing a 6-year-old child is used to test a child restraint that is recommended for children weighing 40 or more lb. Accordingly, we would also use the 6-year-old dummy in compliance tests to test the booster cushion and lap and shoulder belts. We agree with you that when the booster is tested in the configuration intended for children greater than 40 lb., the booster would be used with the vehicle's lap and shoulder belt, without the shield.

There is another matter we would like to address, concerning your labeling of the restraint for children weighing as little as 20 lb. You should note that S5.5.5(f) of Standard 213 prohibits manufacturers from recommending booster seats for children less than 13.6 kilograms (30 lb.). This prohibition is based on test data that showed that the 20 lb. dummy (representing a 9-month-old child) was consistently ejected from booster seats in 30 mile per hour dynamic tests. (See final rule adding the prohibition to Standard 213, 59 Fed. Reg. 37167, July 21, 1994.) NHTSA believes children weighing approximately 20 to 30 lb. need a restraining system that provides a higher degree of upper torso and crotch restraint, such as that provided by convertible or toddler restraints, than that provided by a booster seat. Accordingly, the DBAG booster seat must not be recommended for children weighing less than 30 lb.

We would like to take this opportunity to make one last point before closing. In arguing that the DBAG booster seat should be tested only in accordance with your instructions for using the restraint, you state that Standard 213 "was not designed to sanction improper use or misuse of any child restraint system...." Standard 213 is intended to address, among other things, the problem of misuse of child restraints. It does so by requiring restraints that have features that are likely to be misused to meet performance requirements when installed on the test seat assembly in the "misuse" mode. For example, because NHTSA determined that parents were not attaching the top tethers of child restraints when installing the restraints in their vehicles, Standard 213 was amended to require restraints that have tether straps to meet the standard's requirements with the tether unattached. (See S6.1.2(a)(1), requiring restraints to be secured using only a lap belt and without a tether.) Standard 213 also addresses misuse by standardizing certain aspects of child restraints, such as the manner of installation, to reduce the chance of confusion and incorrect use resulting from such confusion. We believe that the likelihood that parents will misuse a built-in system is reduced when all the components needed to restrain the child are built into the child restraint system.

I hope this information is helpful. Please contact Deirdre Fujita of my staff at (202) 366-2992 if you have other questions.

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosure
ref:213
d.8/4/98

ID: 17539.wkm

Mr. C. Thomas Terry
Director, Safety Affairs and Regulations
General Motors Corporation
30200 Mound Road
Box 9010
Warren, MI 48090-9010

Dear Mr. Terry:

Please pardon the delay in responding to your letter to Mr. John Womack of this office in which you stated that General Motors (GM) is considering the use of dual vacuum hoses between the engine manifold and the booster unit to meet the failed power-assist requirement of Federal Motor Vehicle Safety Standard (Standard) No. 135, Passenger car brake systems.

You stated that the hoses would be connected to the manifold at two separate locations and to two separate non-removable check valves at the booster unit. Thus, failure of one hose would not affect system performance since the other hose would continue to provide vacuum to the booster unit. The check valves would prevent loss of vacuum from the booster in the event of failure of one of the hoses. You asked our agreement that in such a system, only one hose at a time need be disconnected when conducting the failed power-assist test of Standard No. 135, specifically subparagraphs S7.11.3(g) and (h). We have carefully considered your suggested interpretation but, for the reasons discussed below, we do not agree.

Subsection S7.11.4 establishes the applicable performance requirement as follows:

The service brakes on a vehicle equipped with one or more brake power assist units or brake power units, with one such unit inoperative and depleted of all reserve capability, shall stop the vehicle as specified in S7.11.4(a) or S7.11.4(b).

(a) Stopping distance from 100 km/h test speed: 168m (551 ft).

(b) Stopping distance for reduced test speed: S0.10 + 0.0158V.

In testing for this requirement, subparagraph S7.11.3(g) provides:

Disconnect the primary source of power for one brake power assist unit or brake power unit, or one of the brake power unit or brake power assist unit subsystems if two or more subsystems are provided (emphasis added).

Subparagraph S7.11.3(h) provides:

If the brake power unit or power assist unit operates in conjunction with a backup system and the backup system is automatically activated in the event of a primary power service failure, the backup system is operative during this test.

The agency does not consider the use of hoses from the engine manifold to the booster unit as the primary source of power for the brake power-assist system. The power or medium used to operate the brake power assist system is vacuum, the primary source of which is the engine. Thus, the "primary source of power" of a vacuum-operated brake power-assist system is the engine intake manifold, which provides vacuum to the power assist unit regardless of the number of vacuum hoses used to transmit the vacuum. Loss of vacuum generated by the engine constitutes a loss of the primary power source. That is what the failed power-assist test of S7.11 seeks to replicate, that is, the standard seeks to ensure that in the event of loss of power assist, the driver will still be able to bring the vehicle to a stop in the required distance of 168 meters (551 feet) with the prescribed brake pedal force of 500 Newtons.

In this test, therefore, all hoses from the engine intake manifold to the booster unit are disconnected and the system is depleted of vacuum. The stopping tests are then conducted without reconnecting the brake power assist unit to the vacuum source. This is not to imply that the engine is turned off for this portion of the testing, but rather that the source of power, the engine manifold, is disconnected from the power assist unit. I note that with respect to S7.7, Stops with Engine Off, the difference is that residual vacuum remains in the system to be used to power the brake assist unit. For the inoperative brake power assist test, the system and any subsystems must be depleted.

A "backup" system as provided in S7.11.3(h) would be a separate electric or vacuum accumulator that would automatically activate in the event of failure of the primary power source. Thus, the dual hose system you described in your letter would not constitute a backup system. Rather, it would be no more than components of the primary power source.

I hope this information is helpful to you. Should you have any further questions or need additional information, feel free to contact Walter Myers of my staff at this address or at (202) 366-2992, fax (202) 366-3820.

Sincerely,
Frank Seales, Jr.
Chief Counsel
d.7/15/98
ref:105#135

ID: 17556.wkm

Mr. Enzo Bauk
Director of Engineering
Electric Vehicles International LLC
1331 Main Street
Anderson, IN 46016

Dear Mr. Bauk:

This responds to your letter of March 16, 1998 and refers to the telephone conversation of May 20, 1998 between Mr. O. L. Rand of your staff and Walter Myers of my staff. You stated that your company manufactures, among other things, electric buses and trolleys that use air-over-hydraulic (AOH) braking systems. You stated that there are currently no brake systems available that will permit you to comply with the antilock brake system (ABS) requirements of Federal Motor Vehicle Safety Standard (Standard) No. 121, Air brake systems. You enclosed a list of twenty-five manufacturers and suppliers whom you contacted but who could not or would not provide you the required equipment except at considerable additional cost because of the small number of units involved. You stated that you believe that the ABS requirement should not apply to your vehicles "until the market offers a reliable economically viable system for small equipment manufacturers."

Standard No. 121 defines air brake systems as follows:

Air brake system means a system that uses air as a medium for transmitting pressure or force from the driver control to the service brake, including an air-over-hydraulic brake subsystem, but does not include a system that uses compressed air or vacuum only to assist the driver in applying muscular force to hydraulic or mechanical components (emphasis added).

The standard further defines AOH brake systems as:

Air-over-hydraulic brake subsystem means a subsystem of the air brake system that uses compressed air to transmit a force from the driver control to a hydraulic brake system to actuate the service brakes.

Thus, the ABS requirements of Standard No. 121, by their terms, apply to your AOH-equipped vehicles.

In reviewing the list of companies that you contacted for AOH brake systems equipped with ABS, we noted that all those companies are U.S. manufacturers and suppliers. As Mr. Rand and Mr. Myers discussed in their telephone conversation, AOH systems are more commonly used in Europe and Japan than they are in the U.S. Thus, you could perhaps have better luck locating suppliers in those areas that could provide the components that you need. In that connection, I refer you to an article entitled Antilock Brakes, Part II which appears in the March 2, 1998 issue of Transport Topics, commencing at page 12. A brief discussion of the effect of antilock requirements on AOH systems appears at page 16 where the author comments on techniques used by Hino Diesel Trucks engineers in Japan (copy enclosed).

Mr. Rand and Mr. Myers also discussed the provisions of 49 Code of Federal Regulations, Part 555, TEMPORARY EXEMPTION FROM MOTOR VEHICLE SAFETY STANDARDS (copy enclosed). Mr. Taylor Vinson of this office ((202) 366-5263; fax (202) 366-3820) may be contacted for additional information on this procedure.

I hope this information is helpful to you. Should you have other questions or need additional information, feel free to contact Mr. Myers at this address or at (202) 366-2992, fax (202) 366-3820.

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosures
d.7/9/98
ref:121