ID: 1651y

Mr. Wendell D. Kegg
Tire/Wheel Consultants
12190 Hoover Avenue, OH 44685

Dear Mr. Kegg:

This responds to your letter seeking an interpretation of Federal Motor Vehicle Safety Standard No. 110, Tire Selection and Rims. You were uncertain about section S4.3.1's requirements related to the inflation pressure for spare tires specified on vehicle placards. You asked whether a vehicle manufacturer can specify a higher inflation pressure for a spare tire than the maximum inflation pressure molded on the tire's sidewall.

As you know, FMVSS 110 sets forth requirements related to vehicle placards in passenger cars. Section S4.3 requires that the placard be "permanently affixed to the glove compartment door or an equally accessible location" and display the vehicle capacity weight; the designated seating capacity; the vehicle manufacturer's recommended cold tire inflation pressure for maximum loaded weight and, subject to the limitations of S4.3.1, for any other manufacturer-specified vehicle loading condition; and the vehicle manufacturer's recommended tire size designation. FMVSS 110 does not have any provision requiring the inclusion of information on the placard related to spare tires or air pressure related to spare tires. Accordingly, a passenger car manufacturer may, but is not required to, specify information related to spare tires on the placard.

In response to your question whether a passenger car manufacturer can specify a higher inflation pressure for a spare tire than the maximum inflation pressure molded on the spare tire's sidewall, section S4.3.1 of FMVSS 110 states that the vehicle placard must not specify an "inflation pressure other than the maximum permissible inflation pressure" required to be molded on the tire itself by section S4.3 of FMVSS 109, New Pneumatic Tires, unless the alternative inflation pressure satisfies the three conditions set forth in S4.3.1. The first condition requires that the alternative inflation pressure be less than the maximum permissible inflation pressure. The second condition requires that the vehicle loading condition be specified for the alternative reduced pressure. The third condition requires that the tire load rating be specified by an individual manufacturer for the tire size at that inflation pressure that is not less than the vehicle load on the tire for that vehicle loading condition. Accordingly, a vehicle manufacturer could not specify on its placard an inflation pressure that exceeds the maximum permissible inflation pressure.

I am enclosing a December 13, 1984 letter to Mr. Alberto Negro of Fiat, which explains the agency's position concerning a manufacturer's specification on the placard of an inflation pressure that exceeds the maximum inflation pressure molded on the tire. As that letter indicates, a manufacturer would have to meet each of the conditions specified in section S4.3.1, including that the alternative inflation pressure must be less than the maximum permissible inflation pressure. Because spare tires are subject to these requirements like any other pneumatic tire, a vehicle manufacturer could not specify a higher inflation pressure for a spare tire than the maximum inflation pressure molded on that tire.

If you have any further questions or need additional information on this subject, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992.

Sincerely,

Erika Z. Jones Chief Counsel

Enclosure

/ref:109#110 d:l/l8/89

ID: 1982-3.30

TYPE: INTERPRETATION-NHTSA

DATE: 12/08/82

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Lucas Industries Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of November 1, 1982, regarding an interpretation of the "lens area requirements of FMVSS No. 108" as applied to the high contrast lamp whose design you enclosed.

We understand that your design applies to rear lamps. The measurement for the illuminated area of a rear lamp as specified in SAE J585e, "Tail Lamps (Rear Position Lamps)," for example, is stated in part as follows:

. . . "To be considered visible, the lamp must provide an unobstructed projected illuminated area of outer lens surface. . . ."

This applies to the installation requirements, i.e., the device as used on a vehicle. It is not part of the laboratory test procedure.

Further, with regard to photometric requirements of a lamp, no measurement for the illuminated area of a rear lamp is specified in SAE test procedures.

In summary, Standard No. 108 does not prohibit Lucas from manufacturing the lamp in question, but the vehicle manufacturer must be careful to insure that the lamp, when installed, conforms to the standard's requirements for visibility of lens area.

SINCERELY,

NOVEMBER 1, 1982

Office of Chief Counsel, Room 5219 National Highway Traffic Safety Administration

Dear Sir

Subject: Federal Motor Vehicle Safety Standard 108

Our sister company, Lucas Electrical Limited, of Birmingham, England, has developed a "high contrast" lamp design for multifunction rear lamps on motor vehicles. The purpose of this letter is to seek your confirmation of our interpretation of the lens area requirements of FMVSS 108 as applicable to this design.

The Lucas high contrast design uses a conventional rear lamp bulb and reflector to direct light on to convex cylindrical lensing which is colored red, yellow or white according to the function. An opaque screen of any color having slits running in the same direction and parallel to the flutes of the lens is positioned between the inner and an outer lens. The outer lens has fluting at right angles to that of the inner lens and can be clear, tinted or of neutral density. A copy of U.S. Patent 4,241,388 is attached for more explicit information.

In operation, light from the bulb is directed as parallel rays onto the inner cylindrical lensing which focuses it through the slits in the opaque screen. After passing through the slits in the screen, the rays of light diverge and then strike the outer lens where they are refracted in a plane at right angles to the slits. To an observer, the light emitted by the lamp will be the color of the inner lens and will be in contrast to the appearance of the unilluminated lamp.

It is our interpretation that with such a lamp the projected luminous and illuminated areas requirements of FMVSS 108 are those of the outer lens rather than those of the slits behind it. We hope you will confirm this opinion.

LUCAS INDUSTRIES INC

A J Burgess Vice President (Technical)

United States Patent [19] Green

[11] 4,241,388 [45] Dec. 23, 1980

(Graphics omitted)

(Graphics omitted)

FIG.6.

(Graphics omitted)

ID: 1982-3.35

TYPE: INTERPRETATION-NHTSA

DATE: 12/22/82

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Automobile Importers of America Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your letter asking about the identification requirements of FMVSS 101, Controls and Displays. You asked whether it is permissible for a manufacturer to identify a certain manual control with the symbol specified by the European Economic Community (EEC) for the cold start control. According to your letter, the control resets injection timing and actuates cylinder warming.

By way of background information, the agency does not provide approvals of motor vehicles or motor vehicle equipment. The Vehicle Safety Act requires that each manufacturer assure that its products are in compliance with all applicable standards. The following only represents the agency's opinion based on the specific facts provided in your letter.

The answer to your question is yes, since Standard No. 101 does not include any identification requirements applicable to that specific type of control.

Section S5 of Standard No. 101 requires each passenger car manufactured with any control listed in S5.1 or in column 1 of Table I to meet the requirements of the standard for the location, identification and illumination of such control.

Neither section S5.1 nor column 1 of Table I list or include a single control which operates the two functions noted above.

Since Standard No. 101 does not include any identification requirements applicable to that type of control, identification is at the discretion of the manufacturer. It is therefore permissible, under that standard, to identify that type of control with the symbol specified by the EEC.

SINCERELY,

AUTOMOBILE IMPORTERS OF AMERICA, INC.

May 27, 1982

Frank A. Berndt, Chief Counsel National Highway Traffic Safety Administration

Dear Mr. Berndt:

One of our member companies would like an interpretation of FMVSS 101-80, Controls and Displays, as it applies to a specific design.

This passenger car is equipped with a diesel engine but the cold-starting control is not an automatic device linked to the ignition switch as are many designs. This particular model uses a manual control which resets injection timing and actuates cylinder warning.

European authorities require that the cold-start control symbol (Figure 19 of EEC Directive 78/316) be used to identify this control for those vehicles sold in Europe. Is it permissible for this symbol to be used for vehicles sold in the United States?

FMVSS 101-80, Controls and Displays, calls for any control item which is listed in Table I of the standard to be identified as shown in that Table. The diesel cold start control is not listed in Table I; the only similar controls required to be labeled are an engine choke and hand throttle, neither of which pertain to this device.

Does this mean that this device is not required to be identified by words and that the symbol control identification may be used on U.S. cars? If this is the case, the manufacturer will be able to commonize controls with European models and save unnecessary expense.

Bruce Henderson

ID: 1984-2.40

TYPE: INTERPRETATION-NHTSA

DATE: 07/31/84

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Automobile Importers of America,Inc

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. Bruce Henderson Automobile Importers of America, Inc. 1735 Jefferson Davis Highway, Suite 1002 Arlington, Virginia 1002 Dear Mr. Henderson:

This is in reply to your letter to Mr. Vinson of this office, in which you asked for an interpretation of Motor Vehicle Safety Standard No. 108. Specifically, you would like to know whether a supplementary turn signal unit may be added to each front fender near the wheel well of a vehicle already equipped with a turn signal system meeting Standard No. 108. You also asked whether there were any restrictions on the mounting height of such a lamp.

Standard No. 108 allows lighting equipment additional to that required by the standard provided that it does not impair the effectiveness of the lighting equipment that the standard requires (paragraph S4.1.3). The supplementary turn signal unit that you describe would appear to enhance the effectiveness of the required turn signals rather than detract from them. There is no requirement that equipment, added at the option of the manufacturer, meet the specific requirements of the standard applicable to identical or similar items of equipment; i.e., the supplementary unit is not legally required to have the same flash rate as the primary turn signals, nor is it subject to the same mounting height restrictions. Obviously, if these specifications are met, supplementary equipment is less likely to impair the effectiveness of the required equipment within the meaning of S4.1.3.

As you are no doubt aware, some manufacturers are wiring their front side marker lamps to flash with the turn signals. This type of supplementary system is acceptable to us.

I hope that this answers your questions.

Sincerely,

Frank Berndt Chief Counsel

July 17, 1984

Mr. Taylor Vincent Office of Chief Counsel - NOA-30 National Highway Traffic Safety Administration 400 Seventh Street, SW Washington, DC 20590

Dear Mr. Vincent:

We would like to request all interpretation of the application of Federal Motor Vehicle Safety Standards (in particular, FMVSS 108) in the following case:

A passenger car complies fully with the requirements for turn signals in FMVSS 108. Is it permissable to add a "turn signal repeater lamp" to each front fender near the wheel well? This repeater lamp would indicate to a vehicle in an adjacent lane an intention to change lanes. The vehicle would continue to to meet requirements in FMVSS 108 for rate of flash, bulb burnout indications, etc.

If the use of such turn signal repeaters in addition to the "four-corner" signal lamps is permissible, is there any restriction on the mounting height - maximum or minimum?

Thank you for your attention and assistance in this matter.

Sincerely, Bruce Henderson BH:bd

ID: nht89-1.4

TYPE: INTERPRETATION-NHTSA

DATE: 01/18/89

FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TO: WENDELL D. KEGG -- TIRE WHEEL CONSULTANTS

TITLE: NONE

ATTACHMT: LETTER DATED 09/14/88 FROM WENDELL D. KEGG TO ERIKA Z. JONES -- NHTSA, OCC 2560

TEXT: Dear Mr. Kegg:

This responds to your letter seeking an interpretation of Federal Motor Vehicle Safety Standard No. 110, Tire Selection and Rims. You were uncertain about section S4.3.1's requirements related to the inflation pressure for spare tires specified on vehic le placards. You asked whether a vehicle manufacturer can specify a higher inflation pressure for a spare tire than the maximum inflation pressure molded on the tire's sidewall.

As you know, FMVSS 110 sets forth requirements related to vehicle placards in passenger cars. Section S4.3 requires that the placard be "permanently affixed to the glove compartment door or an equally accessible location" and display the vehicle capacit y weight; the designated seating capacity; the vehicle manufacturer's recommended cold tire inflation pressure for maximum loaded weight and, subject to the limitations of S4.3.1, for any other manufacturer-specified vehicle loading condition; and the ve hicle manufacturer's recommended tire size designation. FMVSS 110 does not have any provision requiring the inclusion of information on the placard related to spare tires or air pressure related to spare tires. Accordingly, a passenger car manufacturer may, but is not required to, specify information related to spare tires on the placard.

In response to your question whether a passenger car manufacturer can specify a higher inflation pressure for a spare tire than the maximum inflation pressure molded on the spare tire's sidewall, section S4.3.1 of FMVSS 110 states that the vehicle placar d must not specify an "inflation pressure other than the maximum permissible inflation pressure" required to be molded on the tire itself by section S4.3 of FMVSS 109, New Pneumatic Tires, unless the alternative inflation pressure satisfies the three con ditions set forth in S4.3.1. The first condition requires that the alternative inflation pressure be less than the maximum permissible inflation pressure. The second condition requires that the vehicle loading condition be specified for the alternative reduced pressure. The third condition requires that the tire load rating be specified by an individual manufacturer for the tire size at that inflation pressure that

is not less than the vehicle load on the tire for that vehicle loading condition. Accordingly, a vehicle manufacturer could not specify on its placard an inflation pressure that exceeds the maximum permissible inflation pressure.

I am enclosing a December 13, 1984 letter to Mr. Alberto Negro of Fiat, which explains the agency's position concerning a manufacturer's specification on the placard of an inflation pressure that exceeds the maximum inflation pressure molded on the tire. As that letter indicates, a manufacturer would have to meet each of the conditions specified in section S4.3.1, including that the alternative inflation pressure must be less than the maximum permissible inflation pressure. Because spare tires are sub ject to these requirements like any other pneumatic tire, a vehicle manufacturer could not specify a higher inflation pressure for a spare tire than the maximum inflation pressure molded on that tire.

If you have any further questions or need additional information on this subject, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992.

Sincerely,

ENCLOSURE

ID: 77-1.11

TYPE: INTERPRETATION-NHTSA

DATE: 01/26/77

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Mercedes-Benz of North America, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of December 21, 1976, asking whether Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices, and Associated Equipment applies to fog lamps installed on the rear of passenger cars.

No requirements of Standard No. 108 apply to fog lamps and they are subject to regulation by the individual states. Pursuant to S4.1.3, however, they may be prohibited if they impair the effectiveness of lighting equipment required by Standard No. 108.

You also asked that, absent inclusion of these lamps in Standard No. 108, your letter be treated as a petition "for rulemaking to amend Standard No. 108 to include such lighting requirements . . . for optional use on passenger cars." Your submission does not meet the requirements of our procedural regulations, a copy of which I enclose. Specifically, pursuant to 49 CFR 552.4(c) you should "set forth facts which it is claimed establish that an order is necessary." Among these facts should be reasons why you are petitioning for "optional" rather than mandatory use on passenger cars, and why other vehicles are not included in your petition (if, in fact true).

SINCERELY,

MERCEDES - BENZ OF NORTH AMERICA. INC.

December 21, 1976

National Highway Traffic Safety Administration Office of the Chief Counsel

Subject: Request for Interpretation FMVSS 108

FMVSS 108 specifies performance requirements for certain lamps, reflective devices and associated equipment for use on passenger cars. Mercedes-Benz of North America, Inc. hereby requests interpretation as to whether or not this standard applies to the performance and installation of fog lamps installed on the rear of passenger cars.

This request for interpretation specifically concerns those fog lamps currently used in Europe and subject to EEC regulations, a copy of which is enclosed for your review.

These requirements include a minimum candela output of 150 cd to a maximum of 300 cd measured at any test point within +/- 10 degrees right and left of the lamp axis and +/- 5 degrees up and down on the vertical axis.

The effective projected luminous area for these types of lamps is 140 sq. cm (21.7 sq. in.) maximum. These lamps are wired so as to be switched on with the headlamps and front fog lamps. The color emitted from the lamp when lighted is red within the appropriate SAE-CIE coordinates. The lamp is installed on/or at the rear of the vehicle, left of the centerline, no closer than 100 mm from the stop lamp.

Should this type of lighting device be subject to the current requirement of FMVSS 108, an interpretation is requested as to which aspect of performance this lamp should be designed.

Should this type of lighting device not be subject to the above standard, Mercedes-Benz of North America, Inc. hereby petitions for rulemaking to amend Standard 108 to include such lighting requirements as previously described for optional use on passenger cars.

Samples of these types of lighting devices can be made available for review and testing. Should additional data be necessary to further evaluate this type of lighting system as currently regulated by EEC, please do not hesitate to contact this office.

HEINZ W. GERTH

ID: 77-3.40

TYPE: INTERPRETATION-NHTSA

DATE: 08/03/77

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Michelin Tire Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your June 7, 1977, letter asking who must mark a rim in accordance with the requirements of Standard No. 120, Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars, in those cases where the rim is manufactured by one manufacturer and then supplied to a wheel manufacturer who welds the rim to a disc making a completed wheel.

The National Highway Traffic Safety Administration has determined that the rim marking must be undertaken by the rim manufacturer. The rim manufacturer is best able to supply the required rim information and undertake the certification required by S5.2 of the standard. The subsequent addition of the disc to the rim should not alter the information marked on the rim.

SINCERELY,

JUNE 7, 1977

Office of the Chief Counsel National Highway Traffic Safety Administration Department of Transportation

Re: FMVSS 120, Tire Selection and Rims for Motor Vehicles other than Passenger Cars

We are writing to request an interpretation of the rim marking requirement of FMVSS 120 Tire Selection and Rims for Motor Vehicle other than Passenger Cars.

We are interested in the case where a rim manufacturer supplies rims to a wheel manufacturer who then welds these rims to discs thus producing wheels. In such a situation, is the rim manufacturer or the wheel manufacturer responsible for the markings required by FMVSS 120?

Your prompt reply to this inquiry would be appreciated.

MICHELIN TIRE CORPORATION Technical Group

John B. White Engineering Manager Technical Information Dept.

TELEGRAPHIC MESSAGE

NAME OF AGENCY:

Department of Transportation National Highway Traffic Safety Adm. PRECEDENCE Action P (Illegible Word) DATE PREPARED: 8/16/77

SECURITY CLASSIFICATION

TYPE OF (Illegible Word): [x] (Illegible Word) [] BOOK [] MULTIPLE-ADDRESS

NAME: Fred Koch PHONE NUMBER: 202-426-2800

THIS SPACE FOR USE OF COMMUNICATION UNIT: #26417

TO: ROBERT STEVENSON TECHNICAL SALES MANAGER, WHEEL DIVISION GKN SANKEY, LIMITED

PURSUANT TO YOUR TELEPHONE CALL OF AUGUST 15, 1977, TO FRED KOCH REGARDING FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 120, OUR ANSWERS TO YOUR TWO QUESTIONS FOLLOW.

1. REGARDING THE PRESENCE OF MOLDED LETTERING ON RIM SURFACES IDENTIFYING MILL SOURCE OF MATERIAL NOT SPECIFIED IN THE STANDARD, THERE IS NO OBJECTION TO SUCH MARKING APPEARING ON THE FINISHED RIM PROVIDED IT DOES NOT INTERFERE WITH UNDERSTANDING AND CLARITY OF SEPARATE MARKINGS REQUIRED BY THE STANDARD.

2. REGARDING THE SPACING OF NUMBERS ON THE RIM REPRESENTING DATE OF MANUFACTURER, THE INTENT IS TO MINIMIZE AREA OCCUPIED AND TO AVOID IRREGULAR OR INCONSISTENT SPACING AND OPENINGS IN WHICH INFORMATION MIGHT BE LOST OR UNDETECTED. HOWEVER, THE USE OF VERY SHORT SPACING BETWEEN MONTH, DAY, AND YEAR IS NOT PROHIBITED BY THE STANDARD.

E. T. DRIVER, DIRECTOR OFFICE OF CRASH AVOIDANCE MOTOR VEHICLE PROGRAMS NMV-30 PAGE NO.: 2 NO. OF PGS.: 2

ID: nht80-2.40

DATE: 05/29/80

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Isuzu Motors America, Inc.

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. Hiroshi Abe Assistant General Manager Isuzu Motors America, Inc. 21415 Civil Center Drive Southfield, Michigan 48076

Dear Mr. Abe:

This is in response to your letter of April 3, 1980, concerning the application of Federal Motor Vehicle Safety Standard No. 115 to incomplete vehicles.

S4.1 of Standard No. 115 provides that "(e)ach vehicle manufactured in more than one stage shall have a VIN and check digit assigned by the incomplete vehicle manufacturer." Consequently, Isuzu Motors, Inc. would be the entity responsible for assigning the vehicle identification number (VIN) to incomplete vehicles which it ships to the United States.

You wish to know whether the manufacturer identifier in the VIN of each of these vehicles may designate the vehicle as a "truck" instead of as an "incomplete vehicle" if Isuzu knows that the completed vehicle will be a truck.

S4.5.1 of the standard provides that the first three characters of the VIN shall identify the manufacturer, make and type of vehicle. Table I of S4.5.2 delineates the different types of vehicles and includes a separate type designation for "incomplete vehicles." As explained in the preamble to Notice 8 (March 22, 1979, 44 FR 17489, at 17490), the "incomplete vehicle" category was added because "incomplete" vehicle manufacturers would have little way of knowing the final configuration of the vehicles they produce." It was never the intent of the agency, however, to preclude a manufacturer from indicating the precise types of completed vehicles if this is known.

Sincerely,

Frank Berndt Chief Counsel

April 3, 1980 Mr. Frederick Schwarts, Jr. Office of the Chief Counsel National Highway Traffic Safety Administration 400 Seventh Street, S.W. Washington, D.C. 20590

Subject: Incomplete Vehicle Attributes --- FMVSS 115 VIN

Dear Mr. Schwarts:

This letter is intended to seek your advice on whether the use of VIN for our incomplete trucks meets the requirements of FMVSS 115 --- Vehicle Identification Number.

We currently manufacture and ship to the U.S. incomplete vehicles for which we assume "legal responsibility for all duties and liabilities imposed by the Act, with respect to the vehicle as finally manufactured" as specified in 49 CFR Part 567 ---Certification, 567.5(e). All the vehicles are completed into trucks by the final manufacturer in the U.S. Therefore, the vehicle type description shown in the certification label as set forth in 567.5(e) is "Truck."

In light of this situation, we are planning to use the VIN (the first three characters) assigned to our trucks rather than to incomplete vehicles. The same would apply to the VIN appearing on the above-mentioned certification label.

We believe this arrangement would not contradict the requirements of FMVSS Part 115, but would appreciate your confirmation. We are looking forward to hearing from you. Thank you in advance for your cooperation.

Sincerely yours,

H. Abe Assistant General Manager 05/29/80

ID: nht80-2.42

DATE: 06/02/80

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Donald Boyd & Associates, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your recent letter requesting confirmation that large commercial truck tractors do not have to comply with Federal Motor Vehicle Safety Standard No. 216, Roof Crush Resistance. You also asked whether large trucks should be designed to comply with the "belt system" option under Safety Standard No. 208, Occupant Crash Protection.

You are correct in your assumption that large commercial trucks would not have to comply with Safety Standard No. 216 since that standard only applies to passenger cars. You are also correct in stating that trucks with a GVWR greater than 10,000 pounds may meet the seat belt option of Safety Standard No. 208 found in paragraph S4.3.2. Under S4.3.1, manufacturers do have the option of meeting the crash protection requirements of S5 by means that require no action by vehicle occupants (with current technology this means air cushion restraints or automatic seat belts). Further, vehicles manufactured prior to August 15, 1977, were permitted to comply with Safety Standard No. 216 in lieu of the "rollover" requirements of Standard No. 208, and for large trucks this would have been a simple test to meet. However, since the vehicle would also have been required to meet the "frontal" and "lateral" requirements by automatic means if option S4.3.1 were taken, no truck manufacturers chose to comply with the "rollover" requirements of Standard No. 208 via the Standard No. 216 option. Rather, seat belts were installed on all large trucks.

SINCERELY,

DONALD BOYD & ASSOCIATES, INC. Consulting Engineers

April 22, 1980

Office of Chief Counsel National Highway Traffic Safety Administration

Re: Roof Structure Crashworthiness Requirements for large commerciales vehicles

Dear Sir:

Based on my review of Federal Motor Vehicle Safety Standards, I have concluded that it is not necessary for manufacturers of large commercial truck tractors to comply with FMVSS roof crash resistance performance standards. However, I would like to get your opinion.

FMVSS 216 relates to passenger cars and, because of the 5,000 pound test load limitation, cannot be expected to apply to large commercial truck tractors which should experience substantially higher forces in most rollovers. Standard number 208; S4.3 applies to "trucks and multipurpose passenger vehicles with GVWR of more than 10,000 pounds" and provides two options for meeting crashworthiness requirements. Realistically, however, it would seem that truck manufacturers should select one of these (the "belt system" option) because the other option (which refers back to 216 and the 5,000-pound load limitation) would not be expected to provide adequate roof structure to resist a 30 mile per hour rollover of a large commercial truck.

Therefore, I have concluded that large commercial truck tractors should be designed to comply with the "belt system" option of FMVSS 208 to provide better occupant protection and, in meeting the requirements of this option, will satisy the occupant crash protection Federal Motor Vehicle Safety Standards for trucks manufactured prior to August 15, 1977.

I would greatly appreciate a response from you indicating whether my interpretation of these requirements is consistent with that of the Office of the Chief Counsel.

Donald E. Boyd, Ph.D., P.E.

ID: nht73-2.48

DATE: 12/21/73

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

TO: Blue Bird Body Company

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your November 8, 1973, request for an interpretation of the warning signal requirements of Standard No. 121, Air brake systems.

S5.1.5 of that standard states:

A signal, other than a pressure gauge, that gives a continuous warning to a person in the normal driving position when the ignition is in the "on" or "run" position and the air pressure in the service reservoir system is below 60 psi. The signal shall be either visible within the driver's forward field of view, or both audible and visible.

A warning that "the air pressure in the service reservior system is below 60 psi" is intended to mean that a warning device's sensor could be located in the system you described in your letter between the source of air pressure and the check valve(s) required by S5.2.1.5. As you pointed out, this location would sense pressure below 60 psi anywhere from the compressor through the entire service reservior system. A single warning installed before the check valves in a split service brake system would fulfill the requirements of S5.1.5 as long as it is positioned to sense pressure below 60 psi in any part of the split service reservior system.

P2 Your interpretation of the signal requirements is correct. The signal must be both audible and visible, or it must be visible within the driver's forward field of view. A simple audible signal is insufficient, as is a simple visible signal which is not within the driver's forward field of view.

Yours Truly,

November 8, 1973

Richard Dyson Assistant Chief Council NHTSA

Dear Mr. Dyson:

We have several questions relating to FMVSS 121, S5.1.5, warning signal.

Our interpretation of S5.1.4 and S5.1.5 is that a gauge and a signal are required on each service reservior system. Neither a gauge nor a signal are required on the "wet tank" which is between the service tanks and the compressor and is separated from the service tanks by check valves. It seems to us that a signal on the "wet tank" in lieu of on the service tanks might be more effective in warning the operator of the system malfunction. Our reasoning is as follows: If there is no signal on the "wet tank", a failure of any of the components shown in red on the attached sketch would not be known to the operator until the pressure in the service tanks dropped below 60 psi. With a signal on the "wet tank", the operator would immediately be aware of a failure in any of the components from the compressor through the service system.

Will a warning signal on the wet tank in lieu of a signal on each service tank meet the requirements of FMVSS 121? If not, would NHTSA consider such an amendment?

Also, a major brake manufacturer has supplied us with their written interpretation of FMVSS 121, S5.1.5. Their interpretation would allow warning signals to be visible or audible or both. This is in conflict with our understanding of S5.1.5 which says ". . . the signal shall be either visible. . . or both audible and visible." Which is correct?

Thank you for your early reply.

W. G. Milby Project Engineer

cc: Ben Newberry Dave Phelps

(FLOW CHART OMITTED)