ID: nht76-3.39

DATE: 06/21/76

FROM: THOMAS L. HERLIHY FOR STEPHEN P. WOOD -- NHTSA

TO: Mr. Jack Roadman

TITLE: FMVSR INTERPRETATION

TEXT: This is in response to your letters of February 26 and March 8, 1976, concerning the certification of a truck that you wish to build with a chassis that you have purchased from International Harvester. You have indicated that the chassis did not include an engine, transmission, or radiator. You installed a diesel engine, transmission, and a new driveshaft, and made various modifications to the chassis. You have had difficulties in persuading a body manufacturer to install a truck body.

The source of your difficulties appears to be a misunderstanding of the requirements of the National Traffic and Motor Vehicle Safety Act of 1966 (the Act) and the accompanying certification regulations. Pursuant to the Act, the National Highway Traffic Safety Administration has issued Federal motor vehicle safety standards. These standards apply to completed motor vehicles and to certain items of motor vehicle equipment (e.g., brake hoses, tires). The manufacturer of a motor vehicle or an item of equipment to which a standard applies is required by Section 114 of the Act to certify that his product complies with all applicable Federal motor vehicle safety standards.

"Incomplete vehicle" is defined in 49 CFR Part 568, Vehicles Manufactured in Two or More Stages, as:

an assemblage consisting, as a minimum, of frame and chassis structure, power train, steering system, suspension system, and braking system, to the extent that those systems are to be part of the completed vehicle, that requires further manufacturing operations, other than the addition of readily attachable components, such as mirrors or tire and rim assemblies, or minor finishing operations such as painting, to become a completed vehicle.

An incomplete vehicle is, strictly speaking, an item of motor vehicle equipment. There are no Federal motor vehicle safety standards that apply directly to these particular equipment items, and thus there is presently no certification requirement for incomplete vehicles. The manufacturer of an incomplete vehicle is required by Part 568, however, to furnish an "incomplete vehicle document". This document, which is described in @ 568.4, must indicate the conformity status of the incomplete vehicle with respect to each standard that applies to the vehicles into which it may be completed.

The chassis that you bought from International Harvester (IH) was an item of motor vehicle equipment to which no standards apply. Therefore, IH was not required to furnish you with a certification of compliance. Further, the chassis was not an incomplete vehicle because it lacked an engine and transmission. Therefore, IH was not required to furnish an incomplete vehicle document. Because of your operations on the chassis, you are the manufacturer of an incomplete vehicle. You, therefore, are the person required to furnish an incomplete vehicle document.

Your letter also indicated a concern they you were not given a "certificate of origin" by International Harvester when you purchased the chassis. Federal law does not require the issuance of a certificate of origin. Unless you intended to refer to the Section 114 "certification" discussed above, I assume that you have in mind a document that would be the subject of Pennsylvania state law.

Copies of the Act and the certification regulations are enclosed for your convenience.

ID: nht76-3.4

DATE: 03/11/76

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Inertia Switch, Ltd.

TITLE: FMVSS INTERPRETATION

TEXT: I am writing in response to your March 9, 1976, telephone conversation with Mark Schwimmer of this office concerning the meaning of "GVWR" as it appears in Federal Motor Vehicle Safety Standard No. 301-75, Fuel System Integrity.

"GVWR" or "Gross vehicle weight rating" is defined in 49 CFR 571.3 as:

the value specified by the manufacturer as the loaded weight of a single vehicle.

One constraint on this specification is found in @ 567.4(g)(3) of 49 CFR Part 567, Certification, which requires that the GVWR shall not

be less than the sum of the unloaded vehicle weight, rated cargo load, and 150 pounds times the vehicle's designated seating capacity. . . .

An information sheet entitled "Where to Obtain Federal Motor Vehicle Safety Standards and Regulations" is enclosed for your convenience. If you have any further questions, please do not hesitate to write.

ID: nht76-3.40

DATE: 01/20/76

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Department of the Army

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your December 11, 1975, request for copies of the Federal laws relevant to the use of trucks as carriers for snowplows and spreader bodies.

The National Highway Traffic Safety Administration (NHTSA) primarily regulates the manufacture of motor vehicles and motor vehicle equipment pursuant to authority of the National Traffic and Motor Vehicle Safety Act of 1966. You requested copies of the Federal laws pertinent to the "use" of a particular motor vehicle, but standards or laws regulating use are promulgated by the jurisdiction in which a motor vehicle is registered or driven.

It might be noted, however, that motor vehicle safety standards are applicable to the installation of snowplows and spreader bodies on new trucks. For example, paragraph S4.3.1.1 of Motor Vehicle Safety Standard No. 108, Lamps, reflective devices, and associated equipment (49 CFR 571.108), specifies that if motor vehicle equipment, including snowplows, would otherwise prevent compliance with the Standard by any required lamp or reflective device, an auxiliary lamp or reflective device meeting the requirements of the Standard must be provided. Similarily, when a spreader body is installed on a chassicab, the completed trucks must comply with all applicable Federal standards.

The truck dealer or other person who installs motor vehicle equipment on a truck that is certified as being in compliance with motor vehicle safety standards, prior to first sale of the vehicle, is responsible for ensuring that the truck remains in conformity. Failure to do so would constitute a violation of section 108(a)(1) of the National Traffic and Motor Vehicle Safety Act, and subject the responsible party to the civil penalty provisions and other sanctions of the Act.

When a truck has been sold and is in "use", the Act prohibits a manufacturer, distributor, dealer, or repair business from making alterations that render inoperative any devices or elements of design installed in compliance with the Federal safety standards.

Please contact us if we can be of any further assistance.

YOURS TRULY,

DEPARTMENT OF THE ARMY U.S. ARMY COLD REGIONS RESEARCH AND ENGINEERING LABORATORY

DECEMBER 11, 1975

National Highway Traffic Safety Administration Department of Transportation

In a study of snow removal equipment technology we are making for an NSF RANN project we have need for the federal laws applying to use of trucks as carriers for snowplows and spreader bodies (as well as dump bodies). Please furnish us with copies of the relevant laws, or a list which can be used to obtain them from other sources.

Thank you.

L. DAVID MINSK Research Physical Scientist Applied Research Branch

ID: nht76-3.41

DATE: 11/10/76

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Mr. J. W. Lawrence

TITLE: FMVSR INTERPRETATION

TEXT: This is in response to your July 19, 1976, letter requesting an interpretation of @ 567.4(g) of 49 CFR Part 567, Certification, with respect to the listing of pound and kilogram weight ratings.

You have cited my June 30, 1976, letter to Toyota Motor Sales, which stated that weight ratings may be expressed in both pounds and kilograms, provided that each kilogram rating appears "after" the corresponding pound rating. You have also cited 49 CFR Part 567.4(g), which specifies that "Gross Axle Weight Rating" or "GVWR" be "followed by" the pound ratings for each axle, identified in order from front to rear.

If A and B are two items of information on a label, the NHTSA interprets "A is followed by B" to mean "B appears to the right of A or below A or both." We consider "B appears after A" to have the identical meaning.

The pairing of pound and kilogram ratings that is permitted by the interpretation in the Toyota letter must appear hierarchically within the sequence of axle ratings specified in @ 567.4(g). For example, the following listing is permitted:

GAWR FRONT 2000lbs/907kgs Rear 2200lbs/998kgs while the following listing is not permitted:

GAWR FRONT 2000lbs REAR 2200lbs (907kgs/998kgs).

ID: nht76-3.42

DATE: 03/23/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Titan Trailer Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Titan Trailer Corporation's March 2, 1976, question whether certain bulk grain and feed meal trailers manufactured by Titan qualify as bulk agricultural commodity trailers that are permitted until June 30, 1976, to meet emergency and parking brake requirements other than those specified in S5.6 and S5.8 of Standard No. 121, Air Brake Systems.

Sections S5.6 and S5.8 provide that a trailer manufactured before June 30, 1976, that is designed to transport bulk agricultural commodities in off-road harvesting sites and to a processing plant or storage location, as evidenced by skeletal construction that accommodates harvest containers, a maximum length of 28 feet, and an arrangement of air control lines and reservoirs that minimizes damage in field operations, is entitled to a specified option.

From the descriptive material enclosed, it appears that the Titan models 92 and 24 are designed for field use and conform to the criteria of skeletal construction that accomodates a harvest container, despite the fact that the container is permanently attached to the frame that surrounds it. It is not clear that the trailers are not more than 28 feet in length, or that the design positions air lines and reservoirs to minimize field-related damage. Assuming that the length, air lines, and reservoirs do meet these criteria, it appears that the trailers would qualify for the manufacturer option under S5.6 and S5.8.

YOURS TRULY,

Titan Trailer corp.

March 2, 1976

Frank Burndt Acting Chief Counsel

On December 5, 1975, the NHTSA published an amendment to FMVSS 121 on page 235 of volume 40 of the Federal Register. This amendment exempted certain bulk agricultural commodity trailers from the parking brake requirements which had heretofore necessitated the use of spring brakes.

We manufacture a hopper trailer designed exclusively to haul bulk agricultural products. These trailers are frequently drawn through fields at harvest time by farm tractors - the conditions upon which the spring brake exemption was granted.

Several of our competitors, manufacturing similar hopper trailers, have told potential customers that these trailers are included under the spring brake exemption.

We would like to receive an official communication from your office as to whether or not these hopper trailers are covered under the spring brake exemption granted to agricultural commodities. To assist you in making this decision, we have enclosed photographs and a sales brochure pertaining to our hopper trailers.

Since our material orders and our sales will be strongly influenced by your response, we would greatly appreciate a prompt reply to this letter. Please feel free to contact me at (916) 662-3941 should you have any questions.

Thomas M. Tucker Assistant Manager

ID: nht76-3.43

DATE: 02/18/76

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

TO: Oshkosh Truck Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Oshkosh Truck Company's January 22, 1976, question whether a vehicle that complies with S5.1.1 of Standard No. 121, Air Brake System, when it is moving must also comply with the requirement when it is stationary. Section S5.1.1 specifies an air compressor of sufficient capacity to increase air pressure in the supply and service reservoirs from 85 p.s.i. to 100 p.s.i. within a limited period when the engine is operating at the vehicle manufacturer's maximum recommended rpm.

Section S5.1.1 does not specify whether or not the vehicle is moving as a test condition for the requirement. In view of the absence of this test condition, the NHTSA will resolve differences in this test condition in the manufacturer's favor if they affect the outcome of testing.

Yours truly,

ATTACH.

January 22, 1976

T. Herlihy -- National Highway Traffic Safety Administration

Dear Mr. Herlihy:

Based on discussions with Sid Williams it is my understanding that section 5.1.1 of FMVSS 121 does not require that compressor buildup time be tested when the vehicle is stationary. If the vehicle meets compressor buildup time when it is moving, but exceeds compressor buildup time when the vehicle is stationary, it is my understanding that the vehicle qualifies. Please confirm.

Sincerely,

Danny Lanzdorf -- Supervising Engineer

cc. J. Westphal; D. Thekkanath

ID: nht76-3.44

DATE: 01/22/76

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

TO: Wagner Electric Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Wagner Electric Corporation's October 21, 1975, question whether a trailer would satisfy the requirements of S5.2.1.1 of Standard No. 121, Air Brake Systems, to provide a reservoir "that is unaffected by a loss of air pressure in the service brake system," if the reservoir provided is either of two service brake system reservoirs on the vehicle, equipped with a pressure protection valve directly adjacent to each reservoir. The drawings enclosed in your letter indicate that the "protected tank" that is normally provided, separate from the service brake system, would be eliminated and either of the service brake system reservoirs would be used to satisfy S5.2.1.1 in the event of a parking brake application.

Your interpretation of S5.2.1.1 is correct. That section calls for a reservoir of air as an energy source that is used to release the vehicle's parking brakes after an automatic or manual application. In requiring that this reservoir be "unaffected by a loss of air pressure in the service brake system," the NHTSA means that a single failure of the service brake system would not result in loss of this air supply. With the pressure protection valves located as described in your enclosures, it appears that the system would comply with Section S5.2.1.1.

This "single failure" requirement must be distinguished from the requirement of S5.6.3 that the energy source for application of the parking brake be "not affected by loss of air pressure or brake fluid pressure in the service brake system." The NHTSA has interpreted this requirement to require an uninterrupted energy source despite loss of all air pressure from the service brake system. We recognize that the language of the two passages is substantially identical, and should be changed for clarity.

In a recent proposal to revise the parking brake requirements of the standard (40 FR 56920, December 5, 1975), the NHTSA inadvertently failed to make this distinction clear in its newly-proposed definition of "parking brake system" and intends to publish a correction of the proposal in the near future.

Yours truly,

ATTACH.

WAGNER ELECTRIC CORPORATION

October 21, 1975

Chief Counsel -- National Highway Traffic Safety Administration

Re: 49 CFR 571.121

Dear Sir: The early or first generation systems for FMVSS 121 complying trailers have completed almost a year of evaluation. Serious consideration for more economical systems has naturally evolved in this period of time.

In comparing tractor air brake systems and trailer air brake systems it is apparent that a good level of safety is provided on two axle tractors which employ only service reservoirs, i.e., do not have an isolated reservoir for the parking brake system. This introduced the probability that a (Illegible Word) axle trailer could benefit from a similar system schematic.

Our review of FMVSS 121 indicates that the equipment requirements are minimal - in keeping with the NHTSA policy of issuing performance oriented requirements. The system to be discussed later in this document meets all of the equipment requirements and will satisfy the related performance criteria.

In addition, all of the benefits for commercial or non-regulated necessities are maintained.

For introductory purpose we have reproduced the section from FMVSS 121 that deals with trailer equipment requirements:

S5.2.1.1 A reservoir shall be provided that is unaffected by a loss of air pressure in the service brake system.

On single axle trailers utilizing one service reservoir, a separate reservoir or protected reservoir compartment for parking brake control is clearly required to meet S5.2.1.1.

Tandem axle trailers afford other opportunities for system considerations. The system shown on Figure 1 introduces a new set of operating parameters which will in fact eliminate the expense of adding a third (parking brake control) reservoir on tandem axle trailers. We interpret S5.2.1.1 to mean that a single loss of air pressure in the service brake system following pressurization of the reservoir system to 90 psi shall not prevent a single release of the parking brakes.

The system shown on Figure 1 provides a separate reservoir and anti-lock system for the service brakes on each axle. Failure of system A will not reduce the pressure in service reservoir B or vise versa. The presence of one service reservoir pressurized to 90 psi will permit a full release of the parking brakes when the supply line is pressurized to the maximum 45 to 48 psi. The supply line pressure will be limited to this value by the pressure protection valve [which has an integral check valve] in the supply line immediately adjacent to the failed service reservoir. The four parking chambers will then receive a pressure of approximately 66 psi as delivered by the amplifying relay valve which receives air from the intact service reservoir.

This evaluation is based on the venting of one trailer service reservoir to atmosphere after the system is charged to 90 psi. We consider this to be the most extreme service brake system failure which can occur on the trailer. Note that a pressure loss in both service reservoirs would require two service brake system failures. Functional requirements following multiple service system failures is not required in any other section of FMVSS 121 and is not required in S5.2.1.1. We, therefore, conclude that the system shown on Figure 1 meets the intended requirements of S5.2.1.1.

The proposed system provides an opportunity to reduce the cost of the brake system required on tandem axle trailers. A comparison of the proposed system, which is Figure 1, with the existing system as shown on Figure 2 will show that the modification entails the addition of two check valves, one tee and three short lines to the amplifying relay valve and permits the elimination of the large parking brake reservoir, reservoir drain cock, supply line to the reservoir, and the cost of installing the reservoir on the vehicle. All of the parts shown on the schematics are currently being supplied for production FMVSS 121 trailer systems. The cost reduction can not be accurately defined by Wagner, but we estimate that the saving could range from $ 20.00 to $ 30.00 per vehicle depending on variable labor costs, reservoir cost, and vehicle configuration.

We encourage any NHTSA comments or questions regarding the system shown on Figure 1 and the requirements of S5.2.1.1 of FMVSS 121. It has been customary for requests for interpretation to the Chief Counsel's office which seek system or product "endorsement" to be answered by stating that the requesting party should be able to make that determination themselves.

In the instant case, we have made the determination that the dual service - two reservoir brake system for tandem axle trailers (Figure 1) is functionally acceptable and in compliance, and are therefore reporting it as such.

The dual service - two reservoir brake system for tandem axle trailers will be entering production in the immediate future. We would appreciate an acknowledgement of receipt of this letter and are anxious to answer any questions or supply additional information.

If you have any concern for the performance of the dual service - two reservoir brake system for tandem axle trailers or its compliance with respect to FMVSS 121 an early response from you will avoid the possibility of economic loss to the depressed trailer industry if, for some reason, they would have to reconvert this more economical system to earlier configurations.

Very truly yours,

John W. Kourik -- Chief Engineer, Automotive Products

Attachment

(Graphics omitted)

FIGURE 1

DUAL SERVICE - TWO RESERVOIR BRAKE SYSTEM FOR TANDEM AXLE TRAILER

(Graphics omitted)

FIGURE 1

DUAL SERVICE - TWO RESERVOIR BRAKE SYSTEM FOR TANDEM AXLE TRAILER

(Graphics omitted) FIGURE 2

DUAL SERVICE - THREE RESERVOIR BRAKE SYSTEM FOR TANDEM AXLE TRAILER

ID: nht76-3.45

DATE: 03/12/76

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

TO: Rockwell International

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Rockwell International's February 17, 1976, question whether the addition by a manufacturer of a computer power relay unit (CPR) to an antilock system already installed on a vehicle in satisfaction of Standard No. 121, Air Brake Systems, is prohibited by @ 108(a)(2) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. @ 1397(a)(2)). Section 108(a)(2) provides that, with one exception, no manufacturer, distributor, dealer, or repair business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle in compliance with an applicable Federal motor vehicle safety standard. As you describe the CPR function, it is added to a functioning antilock system to sense improper electrical signals and to prevent them from causing the antilock system to release the brakes when they should remain applied. The CPR acts by discontinuing power to the antilock system and warning the driver.

Section 108(a)(2) has been construed by the NHTSA to apply to situations where a system installed in compliance with a safety standard is defeated so that it no longer possesses the performance capabilities considered necessary by the agency and set forth in its standards. The agency has determined that some modifications can be made (e.g., substitution of a bumper that meets current requirements in place of a bumper that meets earlier requirements) as long as the performance required by the standard is met. In the case of your CPR, the issue is whether the addition of a device that shuts off the antilock function under some malfunction circumstances would be considered "knowingly [rendering] inoperative" an element of Standard No. 121.

As you describe the CPR function, it would not. As in other standards, Standard No. 121 contemplates failure of the regulated system and provides for the safest operation of the system under such circumstances. For example, the standard calls for low-air and antilock-failure warning signals (S5.1) and for uninterrupted operation of the air brake system in the event of electrical failure in the antilock system (S5.5). Antilock manufacturers have also provided logic circuits in their systems to sense certain malfunctions and take corrective action. The fact that the Rockwell CPR is additional protection against malfunction that is being added to systems already installed is not a significant distinction. From your description, the CPR does not defeat the designed performance called for by Standard No. 121, and its installation by a manufacturer would not constitute a violation of @ 108(a)(2).

YOURS TRULY,

February 17, 1976

National Highway Traffic Safety Administration

Attention: Office of Defects Investigation

Subject: Rockwell SKID-TROL(R) Request for Interpretation

Under the date of July 10, 1975, Rockwell International wrote to NHTSA advising of a safety related anti-lock problem that existed on some units. Also included in that letter (copy attached) was a reference to a Rockwell developed in-vehicle diagnostic aid that would enhance the operation and safety of the wheel anti-lock device.

This unit is known as the Computer Power Relay (CPR Unit) and its function is to detect unwanted intermittent signals that may be encountered due to mechanical problems, such as loose wheel bearings or misadjusted wheel end parts.

A more detailed description of its function is as follows:

* The CPR unit has been designed to operate in conjunction with Rockwell's SKID-TROL(R) wheel anti-lock system and detects improper sensor-to-rotor gap as soon as it occurs without the brakes being applied. Further, it gives the operator warning of the condition and returns the vehicle to the manual braking mode. A return to manual braking occurs when the unit detects an abnormal solenoid switching that occurs before the brake pedal is depressed. If such a condition should occur, the CPR removes the power to all wheel anti-lock units on the vehicle until the unit is purposely reset and the condition causing the abnormal switching is corrected.

Since July 1975, the unit has been regularly installed with Rockwell SKID-TROL(R) systems with successful results. We have, however, been asked by a customer as to conflict with Sec. 103 (2) (A) of the Safety Act, Public Law 93-492, which reads in part "No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard."

The effect of the CPR unit is the same as that of the normal fail-safe portion of an anti-lock device, except that it has the added advantages of detecting unwanted intermittent signals and is resetable.

In any event, Rockwell International would appreciate NHTSA's interpretation that the unit does not conflict with Sec. 103, paragraph (2) (A) of the Safety Act.

ROCKWELL INTERNATIONAL CORPORATION AUTOMOTIVE OPERATIONS

G. J. Flannery Director - Government Relations

ATTACH.

July 10, 1975

National Highway Traffic Safety Administration

Attention: Office of Defects Investigation

Attached is a copy of our letter to vehicle manufacturers in connection with a safety related wheel anti-lock problem that exists on some units in use and could exist in the future as the result of misassembly in maintenance. Also attached is a listing of vehicle manufacturers to whom this notice has been sent.

The wheel anti-lock system is performing as designed and the malfunction results from mechanical causes rather than electrical. It is expected that the individual vehicle manufacturers receiving this notice will advise NHTSA of the actual number of units released to the field. Rockwell International estimates that the major number of suspect units were assembled during the first few weeks of production of FMVSS #121 type units. A cutoff date of July 1, 1975 has been established to insure that all suspect units are corrected. Rockwell International will advise NHTSA of the total units shipped to vehicle manufacturers as soon as it is available.

Included in the attached notification is a recommendation that wheel bearings should be properly adjusted and wheel ends checked with a Service Aid Tester after maintenance.

Rockwell International has also developed in-vehicle diagnostic equipment that will be available in the near future that detects mechanical problems affecting the wheel anti-lock system.

Rockwell International will, in the interest of highway safety, provide this diagnostic equipment without charge to operators for use in conjunction with Rockwell International wheel anti-lock systems unitl they can be incorporated into new production vehicles.

Rockwell International will continue to make an all out effort to assist vehicle manufacturers in remedying the problem contained in the attached notification.

ROCKWELL INTERNATIONAL CORPORATION AUTOMOTIVE OPERATIONS

G. J. Flannery Director - Government Relations

ID: nht76-3.46

DATE: 01/08/76

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

TO: B. F. Goodrich Engineered Systems Company

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your August 28, 1975, question whether use of compressed air from a trailer air brake system to supply non-brake equipment such as an air suspension would violate the requirements of Standard No. 121, Air Brake Systems.

The answer to your question is no. Standard No. 121 does not contain a prohibition on the use of air pressure from the air brake system for powering auxiliary devices. The vehicle must of course conform to Standard No. 121 following installation of the device, if the installation occurs prior to the first purchase in good faith for purposes other than resale. For example, the brake actuation timing would still be required to meet S5.3.3 of the standard.

Although not a requirement of the standard, the NHTSA does consider it appropriate that a pressure protective valve be placed in the line to the auxiliary device so that a rupture of an auxiliary line does not cause depletion of air pressure in the brake system.

With respect to your request for approval of four installations of auxiliary equipment, the NHTSA does not issue approvals of specific designs, and therefore cannot state that vehicles modified in the described fashion would or would not be capable of meeting all requirements of the standard.

YOURS TRULY,

B. F. Goodrich Engineered Systems Company

August 28, 1975

R. L. Carter Acting Administrator National Highway Traffic Safety Administration U.S. Department of Transportation

The B.F. Goodrich Company has received numerous requests from our trailer customers asking for our approval to obtain air for auxiliary items, such as air suspension bags from the anti-skid air system.

Attached is one copy each of four drawings, Nos. 1998-42-43-44-45 which shows four different places in the anti-skid air system that air could be obtained for auxiliary items. Drawing -45 shows taking air from the Sealco Ratio Relay Valve. To assist you in evaluating this drawing, we are attaching a Sealco pamphlet describing the operation of the Ratio Relay Valve. We would appreciate your review and interpretation as to whether any or all of these methods would violate the requirements of MVSS-121. We would appreciate an early review of these proposed methods of obtaining air for auxiliary systems so that we will be in a position to properly advise our customers.

If you have any questions concerning information on the attached drawings please do not hesitate to contact me. I will look forward to a response from you and thank you for your consideration.

D. L. Haines Divisional Manager, Quality Assurance

B.F. Goodrich Engineered Systems Company

December 1, 1975

R. L. Carter Acting Administrator National Highway Traffic Safety Administration U.S. Department of Transportation

Subject: Anti-Skid - Containment of Air for Auxiliary Items

Ref: My letter of August 28, 1975

Dear Mr. Carter:

Attached to referenced letter I sent one copy each of four drawings, Nos. 1998-42,43,44,45, showing four different areas in the anti-skid air system that air could be obtained for auxiliary items, such as air suspension bags.

As of this date, we have not received a response on your review and interpretation as to whether any or all of these proposed methods would violate the requirements of MVSS-121.

As I pointed out, B.F. Goodrich has received numerous requests from our trailer customers asking for our approval to obtain air for auxiliary items. Therefore, your prompt response to my August 28 letter will be greatly appreciated.

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

D. L. Haines Divisional Manager, Quality Assurance

ID: nht76-3.47

DATE: 03/30/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Great Dane Trailers, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Great Dane Trailers' February 23, 1976, letter asking if a trailer equipped with one or more axles that have a gross axle weight rating (GAWR) of 24,000 pounds or more is excluded from the requirements of Standard No. 121, Air Brake Systems.

Section S3. of Standard No. 121 provides in part that any vehicle manufactured before September 1, 1977, that has a GAWR for any axle of 24,000 pounds or more is excluded from the standard. The determination of GAWR is made by the vehicle manufacturer (49 CFR 571.3) and must be based on the capabilities of the axle system at 60 mph. Because the determination is made by the vehicle manufacturer, the NHTSA is unable to say that the components you mention in your letter would necessarily constitute an axle system with a GAWR of 24,000 pounds.

YOURS TRULY,

Great Dane Trailers, Inc.

February 23, 1976

James C. Schultz Chief Counsel National Highway Traffic Safety Administration D.O.T.

Re: FMVSS-121 49 CFR 571.121

In accordance with Part 571 Docket No. 74-10; Notice 16 issued May 12, 1975, Section S3. Application, it is stated that FMVSS-121 does not apply to any vehicle manufactured before September 1, 1976, that has a gross axle weight rating (GAWR) for any axle of 24,000 pounds or more.

If we produced a structurally sound semi-trailer with dual tires having a capacity of 6000 pounds each, mounted on an axle with 24,000 pound rating with two springs per axle having a rating of 12,000 pounds each (therefore a 24,000 pound GAWR), is this vehicle exempt from the FMVSS-12 regulations?

I will be looking forward to receiving your legal opinion on this matter.

Dudley E. DeWitt Manager/R & D