ID: nht74-2.47

DATE: 08/27/74

FROM: Frank Berndt; NHTSA

TO: Armstrong Rubber Company

TITLE: FMVSR INTERPRETATION

TEXT: This will confirm that the suggested defect notification letter, enclosed in your letter of August 14, 1974, meets the requirements of 49 CFR Part 577.

We appreciate your taking this action with respect to the Steel Belted Surveyor 78 tire.

ID: nht74-2.48

DATE: 07/26/74

FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA

TO: Stanley Electric Co., Ltd.

COPYEE: L. OWEN

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of July 11 in which you asked what standards will be applied to stop and turn signal lamps after September 1, 1974.

Parking, stop, and turn signal lamps are required by Section S4.1.1.11 and S4.1.1.12 to meet the grouped photometric minimum candlepower requirements specified in Figure 1 of FMVSS No. 108. Prior to September 1, 1974, multiple compartment or multiple lamps need only meet the group value total specified in Figure 1 for a single compartment or single lamp. After that date, however, the higher candlepower values for two and three compartments or lamps specified in Figure 1 are applicable.

Docket 69-19; Notice 3, published in the Federal Register on October 25, 1972, only proposed that SAE (Illegible Word) and (Illegible Word) be referenced in FMVSS No. 108. Until such time as Standard 108 is further amended, SAE J586b, June 1966, and J588d, June 1966, are applicable to stop lamps and turn signal lamps, respectively.

If the new revisions to the SAE standards are included as an amendment to Standard 108, sufficient lead time will be provided to allow the manufacturers to make any changes necessary to meet the new requirements.

Sincerely,

Not Controlled

ATTACH.

STANLEY ELECTRIC CO., LTD.

July 11, 1974

E.T. Driver -- Director Office of Operating Systems Motor Vehicle Programs,

U. S. Department of Transportation, National Highway Traffic Safety Administration

Re: A lamp with two or three lighted compartments used in Stop Lamp and Turn Signal Lamp.

Dear Mr. Driver

According to S 4.1.1.12 in MVSS No. 108 a lamp with two or three lighted compartment is required to meet the minimum photometoric values at each test point specified in table 2 of SAE Standard J575d.

However, after September 1, 1974 a Stop Lamp has to be complied with SAE J586c by P.R. dated October 25, 1972 and SAE J508e for Turn Signal Lamp and further the standards of a lamp with two or three lighted compartments will be applied to a lamp with two or three lighted compartments and by F.R. dated April 9, 1974 the F.R. dated October 25, 1972 has been postponed.

Please let us know what standards will be applied to Stop, Turn Signal Lamp after September 1, 1974, the standards as they are now or the proposal as it is being planned will become effective.

Thanking you in advance for your cooperation,

Very truly yours, H. MIYAZAWA -- Director, Automotive Lighting, Engineering Dept.

ID: nht74-2.49

DATE: MAY 24, 1974

FROM: ALFRED TEVES

TO: JAMES B. GREGORY -- ADMINISTRATOR-NHTSA

TITLE: INTERPRETATION OF FMVSS NO. 105-75

ATTACHMT: 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, MAY 27, 1988 LETTER FROM TEVES TO JONES, AND OCTOBER 9, 1988 LETTER FROM JONES TO BURKARD, EBNER, AND TEVES

TEXT: We wish to request clarification of our interpretation of S5.4.1, Master Cylinder Reservoirs, of FMVSS No. 105-75, (105a) published in the Federal Register on May 18, 1973.

S.5.4.1 reads as follows:

Master Cylinder Reservoirs.

A master cylinder shall have a reservoir compartment for each service brake subsystem serviced by the master cylinder. Loss of fluid from one compartment shall not result in a complete loss of brake fluid from another compartment.

As we understand it, this Section does not prohibit the designs sketched below.

See Illustration on Original

F: Front

R: Rear

C: Clutch

ID: nht74-2.5

DATE: 11/04/74

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: Todco Division

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Todco's September 27, 1974, question whether Standard No. 121, Air brake systems, 49 CFR 571.121, requires a spring brake system on Todco's "Jifflox converter dolly." You describe the Jifflox dolly as a trailer converter dolly which may also be used as a "third axle attachment" on a two-axle truck.

Standard No. 121 applies to vehicles, and specifies separate requirements for trucks, buses, and trailers. It appears that the Jifflox is subject to separate requirements under the standard depending on its use.

If Todco manufactures (Illegible Word) sells the Jifflox for use as a "trailer converter dolly" (defined in 49 CFR 571.3 as a trailer equipped with one or more axles, a lower half of a fifth wheel, and a drawbar), it constitutes a vehicle subject to Standard No. 121. As such it is exempted from the parking brake system requirements (S5.6) and its emergency braking capability is not required to be applied by an emergency source, such as a spring brake, that is not affected by loss of air pressure or brake fluid pressure in the service brake system.

If a truck manufacturer utilizes the Jifflox as an additional axle in the suspension of its vehicle, the truck manufacturer must assure that the truck meets the requirements applicable to it with the Jifflox incorporated in it. This means that, if the truck is manufactured to accept the Jifflox dolly and the truck is rated for a gross vehicle weight rating that depends on inclusion of the axle, the truck must comply with all applicable requirements of the standard with the Jifflox attached. If the truck manufacturer determines that parking brakes are required on the Jifflox axle to meet S5.6.1 or S5.6.2, those parking brakes would have to be applied by an energy source that is not affected by loss of air pressure or brake fluid pressure in the service brake system.

Yours truly,

ATTACH.

September 27, 1974

Richard Dyson -- Chief Council, National Highway Traffic Safety Administration

Dear Mr. Dyson:

This is a second request regarding a ruling on the Jifflox Converter Dolly. This letter is in lieu of our first request of which our copy has been misplaced.

The Jifflox Converter Dolly has been manufactured, sold and licensed as a converter dolly. As stated in F.M.V.S.S.-121 paragraph S.5.8 a converter dolly need not have spring brakes. However, the Jifflox is unique in the fact that it can also be used as a third axle attachment.

In previous conversations with Mr. Sid Williams it has been his opinion that since the Jifflox is sold and licensed as a converter dolly it would be exempt from spring brakes. He reffered us to your office for an official ruling.

Since we deal directly with the truck manufacturers they are obviously concerned with this ruling. They have in fact requested from us an official ruling from your office.

I would think that since the Jifflox is sold throughout the United States, an ammendment to F.M.V.S.S.-121 would be in order. However an official ruling from your office in letter form would suffice.

Since we are a member of the T.T.M.A., I am forwarding a copy of this letter to Mr. Bert Weller, in hopes that research in this matter may be expedited.

If you have any questions regarding this matter, do not hesitate to contact me.

Sincerely

Frank L. Wigand, Eng. Dept. -- TODCO Division

cc: Joseph J. Cunha; Bert Weller

ID: nht74-2.50

DATE: 07/10/74 EST

FROM: RICHARD B. DYSON -- NHTSA ASSISTANT CHIEF COUNSEL

TO: K. NAKAJIMA -- DIRECTOR/GENERAL MANAGER, FACTORY REPRESENTATIVE OFFICE - TOYOTA

TITLE: N40-30

ATTACHMT: OCTOBER 9, 1988 LETTER FROM JONES TO BURKARD, EBNER, AND TEVES, OCTOBER 9, 1981 LETTER FROM BERNDT TO KAWANO, FEBRUARY 3, 1981 LETTER FROM KAWANO TO BERNDT, MAY 24, 1974 LETTER FROM TEVES TO GREGORY, AND MAY 27, 1988 LETTER FROM TEVES TO JONES

TEXT: This is in reply to your letter of May 24, 1974 to Dr. Gregory asking whether the five master cylinder reservoir designs indicated would meet the requirements of S5.4.1 of Motor Vehicle Safety Standard No. 105-75.

Each of these designs appears to conform to S5.4.1 providing that the reservoir capacity requirements of S5.4.2 are met. It appears that Designs (3) and (4) would require additional fluid for the clutch.

ID: nht74-2.6

DATE: 09/26/74

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: Eagle International Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your July 16, 1974, request for approval of the Bendix "dual circuit air brake system" for use on your buses in satisfaction of Standard No. 121, Air brake systems. In a subsequent phone call with Mr. Herlihy of this office, you stated that your only concern was whether the standard requires a parking brake system that meets the axle-by-axle retardation force requirements of S5.6.1 and the grade holding requirements of S5.6.2.

The National Highway Traffic Safety Administration is unable to "approve" plans or prototype systems for compliance with a standard in advance, because there is no way to establish that a vehicle so equipped actually meets the requirements until it has been manufactured.

With regard to your specific question, S5.6 states that each vehicle shall have a parking brake system that meets the requirements of S5.6.1 or S5.6.2 at the manufacturer's option. This means that you are free to choose a system which meets either of these requirements but does not meet both.

Yours truly,

ATTACH.

July 16, 1974

Sid Williams; 400 7th Street, S.W.; Washington, D.C. 20024

Dear Sid:

Enclosed is a copy of our Dual Circuit Air Brake System as developed by the Bendix heavy vehicle system group (their drawing number SA-8117-99). With this is an explanatory writeup describing a circuit operation for normal running, parking position and for service brake failure on the rear or front axle.

We would appreciate receiving your comments and possibly your approval for use in compliance with safety standards #121.

As previously mentioned we would like to avoid the use of spring brakes especially on the tag axle because these wheels are independently sprung and have a tendency to lock up because they do not have a load dividing connection with the drive wheels.

I would appreciate your help on these matters and hope to hear from you soon.

With warmest personal regards,

Sincerely yours,

Harry L. Cuthbert -- Chief Engineer, Eagle International Inc.

Enc: 2

SA-9117-99

EXPLANATORY WRITE-UP

NORMAL RUNNING

1. All reservoirs charged and accessory pressure protection valve open.

2. Parking Control Valve handle in release position. DD-3 Valve (Item 20) does not deliver air. DD-3 locks are disengaged. Service Interlock Valve controlled from its delivery line.

3. "Stand-by" Valve (Item 15) does not deliver any brake valve air, and low pressure indicator switches are open.

4. Service brakes can be applied by treadle valve; primary section of the brake valve applies rear axle and secondary section of the brake valve applies front axle.

SECONDARY BRAKES

1. A service brake failure, which would result in a rear axle circuit reservoir pressure loss will cause the "Stand-by" Valve (Item 15) to open. This will supplement the front axle brakes with rear axle brakes by applying modulated from axle circuit service pressure to the parking diaphragm.

2. A front axle circuit service brake failure will only cause a loss of front axle braking. Full service brakes can be applied on the rear axle through the treadle valve (Item 14).

3. In event of a broken treadle, the parking brakes can be applied as a "Back-up" emergency.

PARKING POSITION

1. When Parking Control Valve Handle (Item 18) is moved to the "park" position, the DD3 locks engage. The parking DD3 Valve will first deliver adequate pressure to the DD3 parking diaphragm, and then exhaust it automatically. In this condition, the parking application will remain applied strictly by "a mechanical means."

2. Service Interlock Valve being decontrolled, is closed and parking brakes cannot be released until PP-1 is pushed and a full service application is made and released, in this sequence.

RCF: dw Current for Drawing Revision #7; 6/18/74 (Graphics omitted) ITEM QTY DESCRIPTION 1 1 AIR COMPRESSOR 2 1 GOVERNOR 3 1 RESERVOIR-SUPPLY 4 1 (Illeg.) 5 1 (Illeg.) 6 1 (Illeg.) 7 1 (Illeg.) 8 3 DRAIN COCK 9 1 SAFETY VALVE 10 1 PRESSURE PROTECTION VALVE 11 3 SINGLE CHECK VALVE 12 3 LOW PRESSURE SWITCH 13 2 AIR PRESSURE GAUGE 14 1 (Illeg.) 15 1 (Illeg.)

TWO-STEP RELEASE OF DD-3 ACTUATORS.

2. (Illegible Words)

3. (Illegible Words)

(Graphics omitted)

(Illeg. table)

ID: nht74-2.7

DATE: 07/24/74

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: The Bendix Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Bendix's June 10, 1974, request for interpretation of the Standard No. 121 requirement in S5.5.1 that "on a vehicle equipped with an antilock system, electrical failure of any part of the antilock system shall not increase the actuation and release times of the service brakes." You ask whether this language permits use of a separate device that senses electrical failure in the antilock system and automatically reduces pressure to the front brakes as a safety measure. The device would increase brake actuation and release time.

S5.5 is addressed to antilock systems and S5.5.1 mandates that antilock systems be designed not to interfere with air brake performance if they fail electrically. S5.5.1 does not prohibit separate safety devices which are designed to operate in the event of antilock electrical failure to compensate for that failure. Therefore the Bendix automatic front axle limiting system, as we understand its operation, is not prohibited by S5.5.1 simply because it operates when it senses an antilock electrical failure.

Sincerely,

ATTACH.

BENDIX HEAVY VEHICLE SYSTEMS GROUP

James B. Gregory -- Administrator, National Highway Traffic Safety Administration

June 10, 1974

Subject: Request for Interpretation

Re: S5.5.1 (Antilock System Failure) Federal Motor Vehicle Safety Standard No. 121

Gentlemen:

As a result of the adoption of the stopping distance provisions of FMVSS No. 121, higher torque brakes on front axles were required. On certain vehicles, these higher torque brakes created wheel lockup/stability problems which were to be solved or controlled by the use of an antilock system. The Automotive Industry concerns with vehicle stability, as expressed in petitions submitted to NHTSA, are directed towards antilock reliability and stability problems that may be amplified by an antilock system failure.

The concern with vehicle stability due to high torque front brakes are recognized by NHTSA in Docket 74-10, Notice 1, wherein a manual control for limiting front axle braking was proposed. Such proposal was, however, subsequently withdrawn in Docket 74-10, Notice 2, primarily, we suspect, because of the manual control feature.

The Bendix Corporation, Heavy Vehicle Systems Group, has developed an automatic front axle limiting system, separate from the antilock system itself, that will sense an electrical failure of the front axle antilock system and "automatically" reduce front axle braking to 50% of that normally provided. Attention is invited to the performance comparison (Enclosure 1) wherein the automatic limiting curve reflects that 120 psi rear axle pressure is required to reach 60 psi at the front axle. While Bendix' system does not introduce an air line restriction, it does limit the level of front axle braking pressures so that the 60 psi and 95 psi pressure levels set forth in Section 5.3.3 (Brake Actuation Time) and Section 5.3.4 (Brake Release Time) respectively, are not achieved, nor are the corresponding actuation and release times realized.

Section 5.5.1 (Antilock System Failure) provides that an ". . . electrical failure of any part of the antilock system shall not increase the actuation and release times of the service brakes." Bendix is of the opinion that since the affect on response time is caused by a system separate from the antilock system itself, it is not within the purview of, and hence not in conflict with Section 5.5.1.

An official interpretation is requested from NHTSA as to whether it concurs with Bendix' opinion that the Bendix Automatic Front Axle Limiting System is not covered by the provisions of, and is not in conflict with Section 5.5.1.

We would be happy to discuss the details of this matter if you feel additional information is necessary.

Very truly yours,

R. W. Hildebrandt -- Group Director of Engineering

Attachment

PERFORMANCE COMPARISON

Standard (Non Limiting) System Vs: System With Automatic Limiting Upon Antilock Failure

(Graphics omitted)

Rear Axle Brake Pressure (PSI)

ID: nht74-2.8

DATE: 11/06/74

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: Truck Body and Equipment Association, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your October 3, 1974, questions whether the exemption for 24,000-pound axle vehicles from Standard No. 121, Air brake systems, until September 1, 1976, applies to fire fighting vehicles, and whether a tandem axle assembly consits of two "axle systems" for purposes of our definition of "Gross axle weight rating."

The answer to both of your questions is yes. A fire fighting vehicle would qualify for exemption until 1976 if any of its axles has a gross axle weight rating of 24,000 pounds or more.

A tandem axle assembly, which we understand to mean a running rear assembly consisting of two axles and associated components, comprises two "axle systems." As we pointed out in the preamble to Notice 2 of Docket No. 74-10, the term "axle system" is used only to avoid confusion in situations where a suspension system does not employ an axle (39 FR 17550, May 17, 1974).

Yours truly,

ATTACH.

TRUCK BODY AND EQUIPMENT ASSOCIATION, (Illegible Word)

October 3, 1974

Richard Dyson -- Office of Chief Council, National Highway Traffic Safety Administration

Dear Mr. Dyson:

Recently several members of our Fire Apparatus Manufacturers Division have contacted us with questions concerning FMVSS 121 and its effective date. In order that we may accurately answer these questions, we would like the following clarified.

(1) Does a fire apparatus qualify for the "Special Permit Vehicle" classification if it is equipped with an axle with a GAWR equal to or greater than twenty-four thousand pounds (24,000 lbs.)?

(2) Is a tandem axle assembly comprised of two "Axle Systems", per your GAWR definition?

Your cooperation in this matter is greatly appreciated.

Sincerely yours,

Byron Crampton -- Manager of Engineering Services

ID: nht74-2.9

DATE: 03/19/74

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: American Snowblast Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your March 4, 1974, question whether your rotary snowplows, constructed with four-wheel drive and four-wheel steer and a top speed of 35 miles per hour, must be certified to conform to Federal motor vehicle safety standards. You also asked whether "certified brakes" will be sufficient certification to Standard 121, what the effects of a locked transfer case are on an anti-lock system, and what procedure exists to petition for an exemption from the standard.

I have enclosed an information sheet which explains that the vehicles you build for highway use are motor vehicles subject to the standard. The standard applies to the performance of the vehicle as a whole, not just to the brake system. In the event that the vehicles as completed do not actually comply, it is the manufacturer of the vehicle who is responsible.

I have enclosed a copy of the law and regulations explaining the basis for and necessary procedures to apply for a temporary exemption from our safety standards.

With regard to a locked transfer case, S6.1.11 of the air brake standard requires:

S6.1.11 Special drive conditions. A vehicle equipped with an interlocking axle system or a front wheel drive system that is engaged and disengaged by the driver is tested with the system disengaged.

Yours truly,

ATTACH.

March 4, 1974

Department of Transportation - NHTSA

Attention: Sid Williams

Gentlemen:

Please give us your opinion on where we stand with respect to FMVSS-121.

We build large rotary snowplows (brochure enclosed) which are sold primarily to airports. We do build an average of five or so per year for highway plowing, and this is our area of concern.

These machines are air braked, four wheel drive and four wheel steer, have a top speed of 35 m.p.h., and weigh less than 40,000 lbs. but more than 30,000 lbs.

Our questions are: must we certify; will certified brakes be sufficient to certify the vehicle; what are the effects of a locked transfer case on anti-lock; the procedure for petitioning for an exemption, etc.

Sincerely

AMERICAN SNOWBLAST CORPORATION;

D. L. Massy -- Chief Engineer

Enclosure Omitted.

ID: nht74-3.1

DATE: 07/30/74

FROM: RICHARD B. DYSON -- NHTSA ACTING CHIEF COUNSEL

TO: P. K. KAMATH -- SENIOR SAFETY ENGINEER OSHKOSH TRUCK CORPORATION

TITLE: N40-30 [ZTV]

ATTACHMT: LETTER DATED 07/09/74 FROM P.K. KAMATH TO RICHARD DYSON -- NHTSA, 49CFR PART 571 FMVSS 101; CONTROL LOCATION, IDENTIFICATION AND ILLUMINATION

TEXT: Dear Mr. Kamath:

This is in reply to your letter of July 9, 1974, asking whether Standard No. 101 requires identification and illumination of an emergency engine stop control, in addition to the engine stop control intended for normal use.

The "engine stop" control referred to in Standard No. 101 means any control used to stop the engine, and would include the emergency control. If it is important for the normal control to be identified and illuminated, it is all the more important that a control intended for emergency use meet the requirements of the standard. Identification such as "emergency engine stop" would be acceptable under Standard No. 101. Illumination, of course, must meet the requirements of the standard, but since you have not described the emergency system or its location we cannot offer a more precise comment.

Yours truly,