ID: aiam0297

Dear Mr. Niguma: This is in reply to your letter of January 23, 1971, to Mr. Rodolfo A Diaz, regarding attachment bolts used to secure seat belt assemblies to a motor vehicle.; The intent of the requirement in paragraph S4.3(c)(1) of Standard 20 is to assure that inadequate attachment bolts will not be used to attach seat belt assemblies to the vehicle. This paragraph does not require that the specific models of vehicles be listed on the label. It provides that if a seat belt assembly is *designed* for use in specific vehicles in which *only* one end of a belt assembly can be attached by a single bolt, then the bolt need only have a breaking strength of 5,000 pounds.; It should be noted, however, that paragraph S4.1(1) of the Standar requires the manufacturer of seat belt assemblies for aftermarket use to furnish an instruction sheet stating whether the assembly is for universal installation or for installation only in specifically stated motor vehicles. If, as you state, the seat belt assemblies used in MAZDA vehicles are designed exclusively for specific models, such models must be listed on the installation instruction sheet.; Please contact us if we can be of further assistance. Sincerely, Clue D. Ferguson, Director, Office of Crashworthiness, Moto Vehicle Programs;

ID: aiam1170

Dear Mr. Gilleran: This is in reply to your letter of June 21, 1973, concerning Standar No. 123 in which you reference a discussion with Mr. Vinson of this office and ask whether a neutral gear indicator must be provided on motorcycles manufactured on or after September 1, 1974.; Paragraph S5.2.2 *Display illumination and operation* states 'If a item of equipment listed in Table 2, Column 1, is provided, the display for such item shall ... illuminate as specified in Column 2, and shall operate as specified in Column 3'.; One of the two equipment items listed in Table 2 is 'Neutra indication'. However, Paragraph S5.2.2 does not require that the item be provided, only that, if a manufacturer provides it, it shall be a green display lamp and it shall illuminate when the gear selector is in the neutral position.; You are right that this interpretation is at variance with the preambl statement that 'Illumination of the neutral position has been deemed essential'. We are considering whether rulemaking action should be taken on this subject.; Yours truly, Richard B. Dyson, Assistant Chief Counsel

ID: nht87-1.72

TYPE: INTERPRETATION-NHTSA

DATE: APRIL 27, 1987

FROM: KOJI TOKUNAGA -- MANAGER, ISUZU MOTORS

TO: ERIKA Z. JONES -- CHIEF COUNSEL, NHTSA

TITLE: FMVSS 124 - ACCELERATOR CONTROL SYSTEMS

ATTACHMT: ATTACHED TO MEMO DATED 8-8-88, TO KOJI TOKUNAGA, FROM ERIKA Z. JONES, STD. 124

TEXT: The purpose of this letter is to seek your agency's interpretation of some requirements of FMVSS 124 - Accelerator Control Systems in the specific context of a new system to be used for our vehicles.

This system features electric control. The system's outline is explained below and illustrated on the attached sheet.

As the accelerator pedal is depressed by the driver, the amount of pedal displacement is converted into proportional electric signals by the accelerator pedal sensor which is in fact a potentiometer equipped with two accelerator pedal position switches. These signals are fed into the control unit where position switch, and then fed into the stepping motor. The stepping motor works to move the throttle lever through the motor's arm and linkage. Thus, the engine speed is controlled in proportion to the amount of accelerator pedal displacement.

The moving components in this system are the accelerator pedal, stepping motor arm, linkage and throttle lever. I would like to receive your answer to the following questions regarding the interpretation of the requirements:

1. Energy sources (S5. 1)

In this vehicle, Isuzu considers the battery that drives the stepping motor to be one of the energy sources under S5. 1, and the return springs (accelerator pedal and throttle lever return springs) the other sources. Is this interpretation correct?

2. Disconnection or severance (S5. 2)

a. Is a severance in electric wires in this system a severance or disconnection within the meaning of S5.2? Isuzu considers negative because electric wires are not a moving part.

b. If a severance in electric wires were a severance or disconnection under S5.2, what about a short-circuiting that may result from such a severance? Does the Standard require that the throttle returns to the idle position even in such a condition?

c. Our understanding is that a failure (other than severance or disconnection) of a system component itself (i.e. a failure in the accelerator pedal sensor with pedal position switches, control unit, throttle valve position switch, or stepping motor) is not subject to the throttle return requirement under the Standard. Is this correct?

3. Definition of "driver-operated accelerator control system"

It is our interpretation that the battery and the electric wires from the battery to the control unit are not a part of the accelerator control system under this definition. Is this interpretation correct?

Vehicles equipped with this control system are already distributed in Japan, and we would like to introduce such vehicles to our U.S. customers as soon as possible. Therefore, your prompt review of, and answer to, these questions would be greatly apprec iated.

I am looking forward to hearing from you on this subject.

Attached sheet

Battery

Throttle valve position switch

Accelerator pedal sensor with accelerator pedal position switches

Arm

Throttle lever

Linkage

Return springs

Stepping motor

Accelerator pedal

Return spring

Control unit

Electric wire

Accelerator Control System

ID: aiam1960

Dear Ms. Hoffman: This is in response to your letter inquiring whether certain automotiv products are subject to the defect reporting requirements of the Traffic Safety Act (Section 158(a)(1)), and whether manufacturers are required to submit defect reports on communications arising out of improper customer maintenance or abuse.; Section 102(4) of the Traffic Safety Act defines 'motor vehicl equipment', in part, as:; >>>'. . . any system, part, or component of a motor vehicle a originally manufactured or any similar part or component manufactured or sold for replacement or improvement of such system, part, or component or as any accessory, or addition to the motor vehicle . . .'<<<; Thus, any item of equipment which becomes 'part' of the motor vehicl is an item of motor vehicle equipment covered by the Act. We further have determined that any item of equipment intended by the equipment manufacturer for use principally by the user of a motor vehicle, or any item that is normally kept in the vehicle, is an 'accessory' to the vehicle and is also covered by the Act.; In deciding whether or not the items listed in your letter are items o motor vehicle equipment and thus subject to the defect reporting requirements of the Act, the above factors were considered. In the list below, those items not considered motor vehicle equipment are 'repair shop items,' not intended for principal use by the user of a motor vehicle. The particular reason for the inclusion of each of the other items within the coverage of the Act is given following each item.; *Hand tools*: >>>Lugnut tightner (sic): Yes, because it is principally intended fo use by a motor vehicle user with the vehicle. Therefore, it is an accessory.; Clutch adjusting tool: No. It is not an accessory as principal intende use is by someone other than the user, such as a repairman.; Feeler gauge: No. Battery carrier: No. Point file: No. Ratchet wrench: No.<<< *Mechanical tools*: >>>Sanders: No. Pullers: No. Crankshaft grinder: No. Honing machine: No.<<< *Repair kits*: >>>Soldering/welding kits: No. Tire repair kits: Yes, because the plugs, cement, vulcanizing liqui and patches become part of the tire and thus part of the motor vehicle.<<<; *Suspension devices*: >>>Sway bars: Yes, because they become part of the vehicle whe attached thereto.; Steering stabilizers: Yes, because they become part of the vehicle whe attached thereto.; Wheel balancers: If you are referring to the machine used to balanc wheels, then it is not an item of motor vehicle equipment as it is not an accessory. If you are referring to the actual weights attached to the wheels, then they are motor vehicle equipment because they become part of the vehicle.<<<; *Towing devices*: >>>Chains: Yes, because during the towing operation, they become par of the vehicle.; Hitches: Yes, because they are attached to the vehicle and thereb become part of it.; Towbars: Yes, because during the towing operation, they become part o the vehicle.<<<; *Test instruments*: Timing light: No. Tire gauges: Yes, to the extent that they are sold principally t owners for use with the vehicle.; Compression tester: No. Vacuum and fuel pump tester: No.<<< *Chemicals*: >>>Traction compound chemical: If by this you mean some sort o substance designed to help owners get their vehicle moving on slippery surfaces, then it is an accessory and is covered.; Lubricants: Yes, because they become part of the vehicle.<<< *Miscellaneous*: >>>Anti-theft devices: Yes, because they become part of the vehicle. Battery cables: Yes, if they are sold to vehicle users for us primarily with (sic) vehicle.; Battery charger: No. Fire extinguisher: Yes, if it is sold principally to users for use wit the vehicle.; Flares: Yes, because they (sic) principally intended for use with th vehicle by users.; Fusees (sic): Yes, because they are principally intended for use wit the vehicle by users.; Mudflaps: Yes, because they become part of the motor vehicle. Traction bars: Yes, because upon installation they become part of th vehicle.; Wheel adaptors: Yes, because upon installation they become part of th vehicle.<<<; In response to your question concerning the submission of defec reports, it is important to note that the intent of Section 158 of the Act is to provide the National Highway Traffic Safety Administration (NHTSA) with the information it needs in order to fulfill its responsibility to examine manufacturers' judgments regarding the relationship to safety of vehicle and equipment defects. If a manufacturer discovers a safety-related defect in its product the manufacturer is avoiding the imposition of a penalty by forwarding copies of communications regarding such defect to NHTSA. If, on the other hand, the product does not contain a safety-related defect, the manufacturer does not incur any liability for having forwarded copies of communications concerning the defect to the NHTSA.; The regulations concerning defect reporting provide that onl communications 'sent to more than one dealer or purchaser . . .regarding such defect' be forwarded to the NHTSA (49 CFR SS 573.4(c)(8) and 573.7). It would appear that the communications about which you are concerned are principally individual communications to individual purchasers or dealers. The manufacturer would not have to submit copies of such communications to the NHTSA. This provision is carried over into the proposed amendments to Part 573 which are being issued in order to bring the regulation into line with Section 158 by including equipment manufacturers (39 F.R. 1863, January 15, 1974, 39 F.R. 43075, December 10, 1974).; If you have any further questions, please feel free to contact us. Yours truly, Richard B. Dyson, Assistant Chief Counsel

ID: aiam0476

Dear Mr. Nakajima: As indicated to you in the November 1 meeting in Mr. Laskin's office the seat belt retractor demonstrated by Toyota and shown on page 9 of the attachment to your letter is considered by the National Highway Traffic Safety Administration to be an automatic locking retractor. The classification of a retractor is determined by its operation, not by its design, and the Toyota retractor, however unconventional in design, operates in the manner prescribed for automatic locking retractors.; With respect to the test procedure of S5.3(a)(6), it is the intent o the test to load the seat belt assembly in a manner that represents the type of tension encountered in use. It is our opinion that the test set up shown on page 9 of the attachment to your letter is a correct application of the procedure to the Toyota retractor.; Please advise us if we can be of further assistance. Sincerely, Lawrence R. Schneider, Chief Counsel

ID: 2834o

Bill Hunt, Project Engineer
Telex Communications, Inc.
8601 Northeast Highway 6
Lincoln, NE 68505

Dear Mr. Hunt:

This letter responds to your inquiry of November 3, 1987, in which you enclosed a diagram to show the relationship between your company, Telex Communications, Inc. (Telex or your company), and a Telex customer you designated as Company XYZ (or your customer). As I understand your diagram, Telex manufactures a trailer which it sells to Company XYZ. Company XYZ then delivers the trailer to its subcontractors, Companies ABC and DEF, who install items such as generators and communications equipment.

Your letter suggests that you are uncertain about your company's certification responsibility. It is your company's position that as an incomplete vehicle manufacturer, you should provide the document specified in 49 CFR 568.4(a). On the other hand, your customer asserts that as the incomplete vehicle manufacturer, Telex must assume legal responsibility for the incomplete vehicle under 49 CFR 568.7(a), and certify the vehicle's compliance under Part 567. On a number of occasions, you spoke with Joan Tilghman of my staff on the matters raised in your letter.

On the diagram enclosed with your letter, you state that the trailers Telex delivered to Company XYZ are equipped with "running gear, brakes, lights, etc." Telex assigns a VIN, gross axle weight rating, and a gross vehicle weight rating to each trailer it delivers to Company XYZ. You are concerned because two contractors with whom you have no relationship add equipment to the trailer after you deliver it to your customer.

First, having reviewed the drawing of the trailer and the narrative information in your letter, it is not clear to me whether your trailers are, in fact, incomplete vehicles. You may wish to provide me with information that more completely describes your trailer so that I may give a more definitive answer to your question. A photograph showing the trailer as it is delivered to Company XYZ would be helpful. However, I shall be as responsive as I can be given the information you supplied in your letter. If the trailers are incomplete vehicles, then Part 568 would not compel your company to certify the trailers' compliance with all applicable Federal safety standards. Under 568.7, Telex may elect to assume legal responsibility for all the certification duties and liabilities imposed on a manufacturer under the National Traffic and Motor Vehicle Safety Act, and affix the certification label as specified in 567.5(e). But if Telex decides against assuming certification responsibility, then it must supply the incomplete vehicle document specified in 568.4.

If the trailers are completed vehicles which are converted to a different use by Company XYZ through its subcontractors, you must certify them irrespective of whether your customer contracts to have other equipment added to the vehicles after delivery. The fact that your customer contracts to have a generator and communications equipment added does not mean that the vehicle requires further manufacturing operations to perform its intended function. The determination of whether a vehicle requires further manufacturing operations to perform its intended functions is not a subjective inquiry into what use the particular person to whom the vehicle is delivered intends to make of the vehicle. In previous interpretations, we have explained that the question is whether the particular vehicle type (e.g., trailer, van) requires further manufacturing operations to perform the customary functions that an ordinary purchaser would expect of this vehicle type.

For example, a van that is delivered to a dealer ready for road use is a completed vehicle, even if the dealer intends to send it to a van converter to have different equipment (seats, refrigerators, etc.) installed before selling the van to a retail customer. Similarly, the trailer your company delivers to Company XYZ is a completed vehicle if it needs no further manufacturing operations to perform the functions an ordinary purchaser would expect of a trailer.

Under the National Traffic and Motor Vehicle Safety Act (Vehicle Safety Act), a complete vehicle manufacturer's certification responsibilities apply up to the vehicle's first purchase in good faith for purposes other than resale. It appears from your letter that Company XYZ purchases your trailers for purposes other than resale, and that after its purchase, Company XYZ subcontracts with two other companies to add a generator and communications equipment to the trailers. If my assumptions are correct, then the two subcontracting companies have no certification responsibilities under the Vehicle Safety Act, because they are modifying vehicles after their first purchase in good faith for purposes other than resale.

The only limitations on the modifications those subcontractors can make to the trailers is set out in 108(a)(2)(A) of the Vehicle Safety Act (15 U.S.C. 1397(a)(2)(A)). That section states that:

No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in 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... If Company XYZ's subcontractors are "manufacturers," distributors," "dealers," or "motor vehicle repair businesses" within the meaning of 108(a)(2)(A), they may not remove, disconnect, or degrade the performance of safety equipment or designs that Telex installed in the trailers in compliance with an applicable Federal safety standard.

I hope you find this information helpful. If you have any further questions on this subject, or wish to provide additional information about the particular relationships that were the subject of this letter, please feel free to contact Ms. Tilghman at this address or by telephone at (202) 366-2992.

Sincerely,

Erika Z. Jones Chief Counsel

ref:VSA#567&568 d:3/l/88

ID: 2809yy

Mr. Thomas D. Turner
Manager, Engineering Services
Blue Bird Body Company
P.O. Box 937
Fort Valley, GA 31030

Dear Mr. Turner:

This responds to your inquiry concerning the applicability of Federal Motor Vehicle Safety Standard No. 221; School Bus Body Joint Strength, to specific joints attaching the floor and stepwell of a school bus. Your letter included a blueprint of the floor and stepwell structure of a large school bus, and asked whether the joints joining the stepwell to the Number 1 and 2 floor sections of the bus are required to comply with the joint strength requirement of Standard No. 221.

Based on the information provided in your letter, I conclude that the joints attaching the floor sections to the stepwell are required to comply with the joint strength requirement contained in S5 of Standard 221. I also conclude that the joints in the stepwell are subject to that requirement.

As you are aware, S4 of the Standard defines "body panel" as:

"...a body component used on the exterior or interior surface to enclose the bus' occupant space."

S4 also defines "body panel joint" as:

"...the area of contact or close proximity between the edges of a body panel and another body component, excluding spaces designed for ventilation or another functional purpose, and excluding doors, windows, and maintenance access panels."

S5 of the Standard requires that body panel joints must comply with the strength requirement. The floor panels and stepwells of a bus are body components which come within the definition of body panel, as they serve to enclose the occupant space of the bus. The joints attaching the floor panels to the stepwell are body panel joints, since they represent the area of contact between the edges of a body panel (either a floor panel or the stepwell) and another body component (either the stepwell or a floor panel), and do not represent a space designed for ventilation or another functional purpose, or a door, window, or maintenance access panel.

I note that the joints attaching the stepwell to the floor sections are identical to, and in the same horizontal plane as, the joints used elsewhere in the floor assembly. I also note that the stepwell assembly described in your letter is also subject to the joint strength requirement. The various portions of the stepwell serve to enclose the occupant space, and are therefore body components which come within the definition of body panel. Therefore, the joints attaching those portions of the stepwell which enclose the occupant space are body panel joints subject to the requirements of the Standard.

Your letter argues that the stepwell joints are exempted from the definition of "body panel joint" by virtue of their being designed for another functional purpose. You do not, however, state the purpose. I disagree with this assertion. As noted above, S4 of the Standard exempts spaces designed for ventilation or another functional purpose from the definition of body panel joint. The agency's longstanding criterion for determining the applicability of this exemption has been whether the body panel joint in question is considered to have a function in enclosing the occupant space. See, March 18, 1977 letter to W.G. Milby (copy attached).

In this case, the stepwell clearly has the function of enclosing occupant space. I note that, by enclosing occupant space at a location which provides access to the front door, the stepwell occupies a critical location in relation to an important exit. Because of its location, the integrity of the stepwell in a crash is as important as the integrity of any other component comprising the floor.

In addition, you argue that the joints between the floor sections and the stepwell need not comply with S5 because they are below the level of the floor. This argument is based on your interpretation of an April 26, 1976 letter from this office to W.G. Milby at Blue Bird which states that components located entirely below the floor level are not subject to the Standard.

That letter did not intend to exclude from the Standard all portions of a bus located below the plane formed by the primary floorline of the bus. The exclusion of those portions below the floor level was instead predicated on the assumption that there is a body panel (i.e., a floor panel) at floor level which encloses the occupant space, and which is located between the occupant space and that portion of the bus excluded from the standard. I note that the floor level of a bus is not a single continuous plane; it is determined at any particular point by the plane of the panel that comprises the floor at that point. Therefore, I do not agree that the stepwell-to-floor panel joints indicated in your letter are below the floor level or are excluded from the standard's joint strength requirements.

I hope you have found this information useful. Please do not hesitate to contact J. Edward Glancy of my staff at (202) 366-2992 if you have any further questions.

Sincerely,

Paul Jackson Rice Chief Counsel

Enclosures ref:22l d:l/l4/9l

ID: nht91-1.16

DATE: January 14, 1991

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Thomas D. Turner -- Manager, Engineering Services, Blue Bird Body Company

TITLE: None

ATTACHMT: Attached to letter from Frank A. Berndt to W.G. Milby; Also attached to letter dated 3-18-77 from Frank Berndt to W.G. Milby; Also attached to letter dated 8-16-90 from Thomas D. Turner to Paul J. Rice (OCC 5110)

TEXT:

This responds to your inquiry concerning the applicability of Federal Motor Vehicle Safety Standard No. 221; School Bus Body Joint Strength, to specific joints attaching the floor and stepwell of a school bus. Your letter included a blueprint of the floor and stepwell structure of a large school bus, and asked whether the joints joining the stepwell to the Number 1 and 2 floor sections of the bus are required to comply with the joint strength requirement of Standard No. 221.

Based on the information provided in your letter, I conclude that the joints attaching the floor sections to the stepwell are required to comply with the joint strength requirement contained in S5 of Standard 221. I also conclude that the joints in the stepwell are subject to that requirement.

As you are aware, S4 of the Standard defines body panel, as:

"...a body component used on the exterior or interior surface to enclose the bus' occupant space."

S4 also defines "body panel joint" as:

"...the area of contact or close proximity between the edges of a body panel and another body component, excluding spaces designed for ventilation or another functional purpose, and excluding doors, windows, and maintenance access panels."

S5 of the Standard requires that body panel joints must comply with the strength requirement. The floor panels and stepwells of a bus are body components which come within the definition of body panel, as they serve to enclose the occupant space of the bus. The joints attaching the floor panels to the stepwell are body panel joints, since they represent the area of contact between the edges of a body panel (either a floor panel or the stepwell) and another body component (either the stepwell or a floor panel), and do not represent a space designed for ventilation or another functional purpose, or a door, window, or maintenance access panel.

I note that the joints attaching the stepwell to the floor sections are identical to, and in the same horizontal plane as, the joints used elsewhere in the floor assembly. I also note that the stepwell assembly described in your letter is also subject to the joint strength

requirement. The various portions of the stepwell serve to enclose the occupant space, and are therefore body components which come within the definition of body panel. Therefore, the joints attaching those portions of the stepwell which enclose the occupant space are body panel joints subject to the requirements of the Standard.

Your letter argues that the stepwell joints are exempted from the definition of "body panel joint" by virtue of their being designed for another functional purpose. You do not, however, state the purpose. I disagree with this assertion. As noted above, S4 of the Standard exempts spaces designed for ventilation or another functional purpose from the definition of body panel joint. The agency's longstanding criterion for determining the applicability of this exemption has been whether the body panel joint in question is considered to have a function in enclosing the occupant space. See, March 18, 1977 letter to W.G. Milby (copy attached).

In this case, the stepwell clearly has the function of enclosing occupant space. I note that, by enclosing occupant space at a location which provides access to the front door, the stepwell occupies a critical location in relation to an important exit. Because of its location, the integrity of the stepwell in a crash is as important as the integrity of any other component comprising the floor.

In addition, you argue that the joints between the floor sections and the stepwell need not comply with S5 because they are below the level of the floor. This argument is based on your interpretation of an April 26, 1976 letter from this office to W.G. Milby at Blue Bird which states that components located entirely below the floor level are not subject to the Standard.

That letter did not intend to exclude from the Standard all portions of a bus located below the plane formed by the primary floorline of the bus. The exclusion of those portions below the floor level was instead predicated on the assumption that there is a body panel (i.e., a floor panel) at floor level which encloses the occupant space, and which is located between the occupant space and that portion of the bus excluded from the standard. I note that the floor level of a bus is not a single continuous plane; it is determined at any particular point by the plane of the panel that comprises the floor at that point. Therefore, I do not agree that the stepwell-to-floor panel joints indicated in your letter are below the floor level or are excluded from the standard's joint strength requirements.

I hope you have found this information useful. Please do not hesitate to contact J. Edward Glancy of my staff at (202) 366-2992 if you have any further questions.

ID: nht88-2.11

TYPE: INTERPRETATION-NHTSA

DATE: APRIL 29, 1988

FROM: J. E. CARR -- PRODUCT SAFETY AND ENVIRONMENTAL CONTROL

TO: ERIKA JONES -- CHIEF COUNSEL, NHTSA

TITLE: INTERPRETATION OF TERMS FOR FMVSS 124

ATTACHMT: ATTACHED TO MEMO DATED 11-9-88 TO J. E. CARR, FROM ERIKA Z. JONES -- NHTSA, STD 124

TEXT: The increasingly restrictive emissions requirements being specified make it imperative that Diesel Truck Engines have electronic engine controls. On many Caterpillar Truck Engines the traditional mechanical governor is being replaced by an Electronic Co ntrol Module (ECM). Caterpillar is asking NHTSA for interpretation of how the terms used in FMVSS 124 would be applied to an electronic system.

Regulation FMVSS 124, paragraph S5.2, concerns the throttle going to idle if there is a severance or disconnect in the accelerator control system. The accelerator control system is defined as all vehicle components, except the fuel metering device, that regulate engine speed in direct response to movement of the driver-operated control. When the mechanical governor and linkage is replaced by electronics and electrical wires, the distinction of what is part of the accelerator control system and what is part of the fuel metering device requires interpretation.

Attached is a sketch showing 3 types of accelerator control systems either in use or planned by Caterpillar.

Type I is a mechanical linkage pedal to a mechanical governor which moves a fuel rack. This is the mechanical system that has been in production for several years and is shown here for reference only.

Type II is a mechanical linkage connected to an accelerator pedal position sensor which is electrically connected to an Engine Control Module (ECM) and a Brushless Torque Motor (BTM) controling fuel injection by moving the fuel rack. The Caterpillar acce lerator pedal position sensor can be located at the OEM's option but is generally mounted on the engine compartment side of the firewall. Both the ECM and BTM are mounted on the engine. The ECM has a function similar to the mechanical governor in Type I in that it senses pedal position and engine speed along with several other factors and signals the BTM as to the desired amount of fuel to be injected.

Type III is a mechanical linkage to an accelerator pedal position sensor which is electrically connected to an ECM and to individual unit injectors. The ECM is mounted on the engine. The ECM senses pedal position and engine speed along with several oth er factors and signals the individual injectors as to the desired amount of fuel to be injected.

It is Caterpillar's position that in Type II and Type III Systems the term "Driver-Operated Accelerator Control System" includes all linkage and wiring up to the ECM. All other components shown in the sketch (except the battery) are part of the "Fuel Me tering Device".

Caterpillar would like confirmation from NHTSA that our interpretation of the definitions used in FMVSS 124 is correct. We would appreciate a prompt response. If you have any questions, please contact me or Jim McCollum on 309-675-5377.

SYSTEM COMPARISON

TYPE I

GOV RACK

Accelerator pedal

linkage

TYPE II

Accelerator pedal position sensor

Accelerator pedal

Bat.

ECM

BTM

RACK

TYPE III

Accelerator pedal position sensor

Accelerator pedal

ACCELERATOR CONTROL SYSTEM

ECM

Bat.

FUEL METERING DEVICE

ID: 1669y

J.W. Lawrence, Manager, Compliance
Volvo GM Heavy Truck Corporation
7825 National Service Road
Airpark West, P.O. Box 26115
Greensboro, NC 27402-6115

Dear Mr. Lawrence:

This is a response to your letter of October 5, 1988, asking this agency to "reconsider and rescind" an interpretation of Standard 124, Accelerator Control Systems (49 CFR /571.124). The interpretation which was the subject of your request was addressed to Mr. Leon Steenbock and dated March 17, 1988. Mr. Steenbock asked whether it is permissible under Standard 124 to install a locking hand throttle control in a new motor vehicle. In our response to Mr. Steenbock, we stated that while nothing in the Standard prohibits installing a hand-throttle control in a new vehicle, "'locking hand throttle controls' are expressly prohibited by Standard 124."

In your letter, you stated that most (and perhaps all) heavy truck manufacturers install hand throttles for engine warm-up, extended idle periods; and for vocational applications such as pumping, compacting, and mixing. You also stated that your company installs only locking hand throttle controls and that these locking hand throttle controls hold the driver-selected engine idle speed until such time as the driver selects a new idle speed, or disengages the throttle.

In support of your position that the letter to Mr. Steenbock was incorrect, you referred to the agency's response to petitions for reconsideration of Standard 124. NHTSA's response to requests that special provisions be made for hand throttles was as follows:

Mack and Alfa Romeo petitioned that "hand-throttles" and throttle positioners be specifically excluded from the definition of "idle position." Petitioners stated that in the event such a device is used a return to the preset throttle position occurs upon release of the driver-operated accelerator control system. This request is granted. If a driver choose to raise the lowest engine speed threshold by the use of a throttle positioning device, the throttle should return to that new position within the same time requirements specified in section S5.3. Accordingly, the NHTSA is amending the definition of "idle position" to provide for the use of throttle positioners. (37 FR 20033, September 23, 1972.)

In accordance with this stated intent, the definition of "idle position" in S4.1 of Standard 124 was amended to read:

(T)he position of the throttle that will provide the lowest engine speed for existing conditions according to the manufacturers' recommendations. These conditions include, but are not limited to, engine speed adjustments for cold engine, air conditioning equipment, and emission control equipment, and the use of throttle setting devices.

Because of this language, we agree with your position that Standard 124 permits the installation of hand throttles, including locking hand throttle controls, provided that the vehicle's engine returns to the lowest engine speed threshold as adjusted by use of the hand throttle within the time and under the conditions set forth in S5 of Standard 124. To the extent that our March 17, 1988 letter is inconsistent with this interpretation, it is incorrect.

I hope you find this information helpful. If you have further questions, please call Joan F. Tilghman of my staff at (202) 366-2992.

Sincerely,

Erika Z. Jones Chief Counsel

cc: Mr. Leon Steenbock Administrative Manager, Engineering FWD Corporation Clintonville, WI 54929-1590

/ref:124 d:2/l0/89