ID: nht74-1.46

DATE: 11/05/74

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

TO: Midland-Ross Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Midland-Ross' October 8, 1974, clarification of its February 8, 1974, petition for an amendment of S5.1.2.1 and S5.2.1.2 of Standard No. 121, Air brake systems, that would establish separate air reservoir volume requirements for several brake chamber types generally available in the air brake component market. You point out that Midland-Ross was referring to chamber stroke and not chamber diameter as the chamber dimension which could affect the safety of a brake system. You also requested that we adopt SAE Standard J10b instead of J10a as our specification of a reservoir that "withstands" certain internal hydrostatic pressure.

In our denial of your petition, we did understand your point that additional stroke could be discouraged by a reservoir capacity requirement based on chamber size at maximum travel of the piston or diaphragm. We found that the stopping distance requirements in effect mandate the installation of high performance components, and we do not anticipate a safety problem. If a safety problem does arise in the future, we would consider a modification of S5.1.2.1 and S5.2.1.2.

SAE Standard No. J10b is identical to J10a in its requirement that no rupture or permanent circumferential deformation of the reservoir exceed one percent. Therefore, for purposes of S5.1.2.2 and S5.2.1.3, we are adopting SAE J10b as our specification of "withstand" until we undertake further rulemaking.

Yours truly,

ATTACH.

POWER CONTROLS DIVISION Midland-Ross Corporation

October 8, 1974

James B. Gregory -- Administrator, U.S. Department of Transportation, National Highway Traffic Safety Adm.

Dear Mr. Gregory:

Subject: N40-30 (TWH)

Thank you for your response to our petition dated February 8, 1974 in regard to Section S5.1.2.1 and S5.2.1.2 of Standard 121 Air Brake Systems. We feel that our petition may not have been clear in regard to use of small volume chambers which apparently led to your misinterpreting our concern. We also believe you may have referred to the incorrect SAE Standard regarding air reservoirs.

In regard to our petition for clarification of air reservoir required volumes, we made mention of the fact that "current reservoir volume requirement based on maximum displacement encourages the use of small volume chambers". By this statement we did not imply smaller diameter chambers but shorter stroke chambers. It is quite easily determined that little chamber stroke is required if the foundation brakes are carefully adjusted with minimum liner to drum clearance. A chamber with 1.5" stroke could be adequate and will meet all of the standard's requirements. If a vehicle manufacturer would elect to go with this short stroke, he could reduce reservoir capacity by 25%. However, there would be very little safety factor to allow for drum expansion and liner wear. It is this condition of which we are concerned and feel it is wrong to penalize the vehicle manufacturer by requiring them to have larger reservoirs when they attempt to provide this additional safety advantage. We ask that you again review this matter and adopt one of the recommended changes to S5.1.2.1 and S5.2.1.2 as stated in our petition.

In the last paragraph of your response you mention the NHTSA has adopted the SAE Standard No. J10a in regard to the definition of "withstand". We assume you intended to refer to SAE Standard J10b and would appreciate your concurrence with this assumption.

Sincerely,

M. J. Denholm -- Director of Engineering

ID: nht93-9.3

DATE: December 4, 1993

FROM: David Fabrycky

TO: Chief Counsel -- US DOT, NHTSA

TITLE: None

ATTACHMT: Attached To Letter Dated 5/12/94 From John Womack To David Fabrycky (A42; Std. 213; VSA 108(a)(2)(A)

TEXT: Dear Sir,

I and my associates are currently involved in the development of a child safety device that is intended to prevent the inadvertent and curiosty based opening of the safety buckle by a one to six year old. Although there have been many studies done on the value of such a device the Code of Federal Regulations contains many relevant statements regarding the testing and operation of child restraint systems.

I am writing you for the purpose of gaining your insight and opinion as to the relationship between the type of device we have developed and the standards articulated in the Code of Federal Regulations.

Our device is and after-market item purchased by the parent or gaurdian. The device covers the safety buckle and prevents the child from gaining access to the pushbutton. The adult or gaurdian is presumed to possess sufficient mannual dexterity and cognitive skills to easily remove the cover and release the safety belt. The device is also transparent so that the objective is visible.

Regarding the following sections, what is your opinion of the installation of such a device on a child's seat belt buckle in conjuction with other approved devices?

Please find several references to the Code of Federal Regulations followed by specific issues/questions in boldface.

CFR 571.214

S5.4.3.5 Buckle Release. Any buckle in a child restraint system belt assembly designed to restrain a child using the system shall: (a) When tested in accordance with S6.2.1 prior to the dynamic test of S6.1, not release when a force of less than 9 pounds is applied and shall release when a force of not more than 14 pounds is applied:

The device requires that a latch be accuated and the cover pivoted away from the buckle so that the pushbutton can be depressed. If none of the forces required to accomplish these tasks exceed the limits specified, would the device be acceptable.

The device requires the manual dexterity to exert the forces in many directions simulateously. Does this comply with the foregoing requirement?

(b) After the dynamic test S6.1, when tested in accordance with S6.2.3, release when a force of not more than 16 pounds is applied;

2

The device does not bear the restraining force of any test and is designed to operate after any stress as when first installed.

(c) Meet the requirements of S4.3(d)(2) of FMVSS No. 209 (CFR 571.209), except that the minimum surface area for child restraint buckles designed for pushbutton application shall be 0.6 square inch;

The device covers the pushbutton during use. The parent or gaurdian is required to remove the device in order to access the pushbutton.

S6 Test Conditions and procedures.

This section describes in detail the procedures required for child restraint system. How would the addition of the device relate to the objectives of the tests?

S6.2 Buckle Release Test procedure.

This section describes in detail the procedures required for buckle of child restraint systems. How would the addition of the device relate to the objectives of the tests?

What other Regulations seem relevant to the development of our device and do you have other observations or opinions that relate to public policy that I have not mentioned?

Thank you in advance for your prompt response.

Sincerly

ID: nht94-2.66

TYPE: Interpretation-NHTSA

DATE: May 4, 1994

FROM: Richard Kreutziger -- Executive Director, New York State Distributors Ass'n. (OCC-9945)

TO: John Womack -- Acting Chief Counsel, NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 5/18/94 from John Womack to Richard Kreutziger (A42; Std. 217)

TEXT:

I have today received the preliminary data from one of the members of NYSBDA the following "fax".

As noted in the preliminary data of FMVSS 217 - there are a number of bus body distributors. As also noted these are small business operations and many, many things affect their ability to carry on a successful company profitable operation. Among the " things" is keeping current with the "school bus regulations". In the process of their daily business - the sales and pricing of their vehicles to comply with the requirements of state and federal regulations and standards is very important. I hope you are readily able to realize the point I am trying to make. Quick changes can be very detrimental to that profit factor as well as the individual position of accountability to, not only their customers - but to themselves.

As you can readily view from the following "fax" there are certain "conditions" that are acceptable to the manufacturer.

We have a special position here in New York State - in that the state regulations exceed the minimum 217 requirements (except for placement of left side emergency door). NYS requires added emergency exits, such as push-out windows and roof hatches based upon capacity of the vehicle.

The distributors now are faced here in New York State with a very large unknown factor. To meet the state regulations - for door (L/S/E/D) placement - with folding seat cushion - longer body length - aisle dimension factor at L/S/E/D. Anything that you can furnish and supply to me in a timely fashion - to help my association membership will be greatly appreciated.

Attachment

CARPENTER MANUFACTURING, INC.

BULLETIN NO. 94 - 34 May 3, 1994

TO: All Carpenter Distributors

SUBJECT: EMERGENCY EXIT - DELAYED EFFECTIVE DATE

NHTSA has postponed enactment of certain parts of FMVSS 217 relative to emergency exits; this change was to have taken effect on May 2, 1994. We were notified by fax on May 2nd that the effective date of the "additional emergency exit" requirement "has been delayed until September 1, 1994."

Carpenter will allow its distributors to omit certain options on orders currently in-house at no change order fee, provided the following conditions are met:

1. Order is not on schedule or started at time of receipt of change order; 2. Change order must be received by Friday, 5/13/94; 3. Only options on list below can be deleted or changed; 4. No pre-built orders can be changed; 5. Body length change will require cancellation of current order and resubmission of new order at current pricing.

Approved option deletions are:

1. Side emergency door and related components; 2. Flip seats and 4-logged seats; 3. Heater plumbing and routing; 4. Roof hatches and push-out sash not required by state specs.

Please note that the rear door hold-open device and reflective striping around the rear door opening will still be required and cannot be deleted.

You must keep in mind that orders are being schedule constantly; therefore, it is important to get any change order faxed as soon as possible. You will be notified by Martin Miller as to whether or not your change order can be accepted.

You may cover more than one body order on each change order, but all bodies on a given change order must have identical changes.

Todd Bontrager Asst. Vice President of Sales School Bus Division

ID: nht94-6.4

DATE: May 4, 1994

FROM: Richard Kreutziger -- Executive Director, New York State Distributors Ass'n. (OCC-9945)

TO: John Womack -- Acting Chief Counsel, NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 5/18/94 from John Womack to Richard Kreutziger (A42; Std. 217)

TEXT:

I have today received the preliminary data from one of the members of NYSBDA the following "fax".

As noted in the preliminary data of FMVSS 217 - there are a number of bus body distributors. As also noted these are small business operations and many, many things affect their ability to carry on a successful company profitable operation. Among the "things" is keeping current with the "school bus regulations". In the process of their daily business - the sales and pricing of their vehicles to comply with the requirements of state and federal regulations and standards is very important. I hope you are readily able to realize the point I am trying to make. Quick changes can be very detrimental to that profit factor as well as the individual position of accountability to, not only their customers - but to themselves.

As you can readily view from the following "fax" there are certain "conditions" that are acceptable to the manufacturer.

We have a special position here in New York State - in that the state regulations exceed the minimum 217 requirements (except for placement of left side emergency door). NYS requires added emergency exits, such as push-out windows and roof hatches based upon capacity of the vehicle.

The distributors now are faced here in New York State with a very large unknown factor. To meet the state regulations - for door (L/S/E/D) placement - with folding seat cushion - longer body length - aisle dimension factor at L/S/E/D. Anything that you can furnish and supply to me in a timely fashion - to help my association membership will be greatly appreciated.

Attachment

CARPENTER MANUFACTURING, INC.

BULLETIN NO. 94 - 34

May 3, 1994 TO: All Carpenter Distributors

SUBJECT: EMERGENCY EXIT - DELAYED EFFECTIVE DATE

NHTSA has postponed enactment of certain parts of FMVSS 217 relative to emergency exits; this change was to have taken effect on May 2, 1994. We were notified by fax on May 2nd that the effective date of the "additional emergency exit" requirement "has been delayed until September 1, 1994."

Carpenter will allow its distributors to omit certain options on orders currently in-house at no change order fee, provided the following conditions are met:

1. Order is not on schedule or started at time of receipt of change order; 2. Change order must be received by Friday, 5/13/94; 3. Only options on list below can be deleted or changed; 4. No pre-built orders can be changed; 5. Body length change will require cancellation of current order and resubmission of new order at current pricing.

Approved option deletions are:

1. Side emergency door and related components; 2. Flip seats and 4-logged seats; 3. Heater plumbing and routing; 4. Roof hatches and push-out sash not required by state specs.

Please note that the rear door hold-open device and reflective striping around the rear door opening will still be required and cannot be deleted.

You must keep in mind that orders are being schedule constantly; therefore, it is important to get any change order faxed as soon as possible. You will be notified by Martin Miller as to whether or not your change order can be accepted.

You may cover more than one body order on each change order, but all bodies on a given change order must have identical changes.

Todd Bontrager Asst. Vice President of Sales School Bus Division

ID: nht95-1.12

TYPE: INTERPRETATION-NHTSA

DATE: January 5, 1995

FROM: Philip R. Recht -- Chief Counsel, NHTSA

TO: Randal Busick -- President, Vehicle Science Corporation

TITLE: NONE

ATTACHMT: Attached to 10/14/94 letter from Randal Busick to Mary Versailles

TEXT: Dear Mr. Busick:

This responds to your letter of October 14, 1994, concerning whether a belt design would comply with S7.1.2 of Standard No. 208, Occupant Crash Protection, as amended in a final rule published on August 3, 1994 and effective on September 1, 1997 (59 FR 3 9472). As described in your letter, for this belt design, "the inboard lower FMVSS 210 anchorage is located on the seat frame and thus, as the seat moves fore and aft, the system allows a minimum of two seat belt adjustment positions and the distance be tween the two extreme adjustment positions of the system is more than 5 cm."

The August 3 final rule amended Standard No. 208 to improve the fit and increase the comfort of safety belts for a variety of different sized occupants. After the effective date, S7.1.2 will, in pertinent part, read as follows:

. . . for each Type 2 seat belt assembly which is required by Standard No. 208 (49 CFR 571.208), the upper anchorage, or the lower anchorage nearest the intersection of the torso belt and the lap belt, shall include a movable component which has a min imum of two adjustment positions. The distance between the geometric center of the movable component at the two extreme adjustment positions shall be not less than five centimeters, measured linearly.

As illustrated in the drawing provided with your letter, the inboard anchorage on your seat design is the "the lower anchorage nearest the intersection of the torso belt and the lap belt."

It would appear that, under the definition of "seat belt anchorage" in Standard No. 210, Seat Belt Anchorages, the seat would be considered part of the anchorage for your design. Standard No. 210 defines a "seat belt anchorage" as any component, other t han the webbing or straps, involved in transferring seat belt loads to the vehicle structure, including, but not limited to, the attachment hardware, seat frames, seat pedestals, the vehicle structure itself, and any part of the vehicle whose failure cau ses separation of the belt from the vehicle structure.

If the seat is part of the anchorage, and if the seat can be adjusted more than 5 cm, measured linearly, it appears that your design will meet the requirement of S7.1.2.

While not directly relevant to your question, agency technical staff raised concerns about a device in the drawing enclosed with your letter. The drawing of the system shows a device labeled "Slider Bar" to which the outboard lower end of the seat belt anchorage is attached. While no detail is provided on this device, agency staff are concerned that the device (which appears to function as the lower outboard anchorage) allows the seat belt webbing attachment to slide freely fore and aft longitudinally . If our interpretation of the drawing is correct, this device may prevent the belt system from meeting the occupant protection requirements of Standard No. 208, as well as prevent the anchorage from meeting the anchorage location requirements of S4.3 o f Standard No. 210. Finally, the device may introduce slack in the belt system, preventing the belt from adequately securing a child safety restraint in the seat or providing complete protection to an adult.

I hope this information has been helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992.

Sincerely,

ID: nht73-2.2

DATE: 08/30/73

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Electrical Testing Laboratories, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of June 18, 1973, concerning the conformity of certain designs of type III seat belt assemblies with Standard No. 209.

The first feature which you describe is a restraint consisting of a waist band with a single shoulder strap. The shoulder strap is attached to the buckle in front and is looped around the waist band in back. Unless this restraint has more elements then you describe, we haver serious questions about its conformity with the requirements for type III seat belts under Standard 209. Section S4.1(c) provides that the assembly must restrain the upper torso without shifting the pelvic restraint into the abdominal region and that the upper torso restraint shall be designed to minimize its vertical forces on the shoulders and spine. It appears doubtful that the described assembly meets either of these requirements.

The second feature you described is a strap through the harness assembly that passes around the seat back and is anchored to the floor by means of the vehicle's seat belt assembly anchorage. Your question appears to be whether such a restraint is a seat back retainer as required by Section S4.1(h). The attachment you describe would not be a seat back retainer under Section S4.1(h).

The third feature described, a closed loop strap without floor attachment would also violate the requirements of S4.1(h), unless it is designed and labelled for use only in specific models having adequate seat back restraints, as specified in that paragraph.

The fourth feature is the ability of a harness to move freely up and down on the restraint strap. This feature is the ability of harness to move freely up and down on the restraint strap. This feature is allowable under Standard 209.

Yours truly,

ELECTRICAL TESTING LABORATORISE, INC.

June 18, 1973

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

Subject: Type 3 Seat Belt Assemblies.

Dear Mr. Dyson:

We have recently been asked to perform tests on type III seat belt assemblies, the design of which has caused us some doubt as to their meeting some of the requirements of FMVSS 209. What we would like to know is whether or not the following design features are acceptable under the requirements for type III seat belt assemblies as outlined in FMVSS 209.

1. Upper torso restraint: Restraint consists of single strap starting at the midpoint of the pelvic band (strap around the waist). The anchor point is the buckle tongue hardware. The strap then passes over on shoulder of the child and is terminated in a loop through which the pelvic belt passes freely.

2. Seat Back Retainer: Strap passes through harness assembly around seat in a closed loop and is anchored to the vehicle by a narrow anchor plate using the same bolt as used to secure the seat belt assembly. This installation is performed by the purchaser.

3. Strap: The harness assembly is secured to the seat back by a closed loop strap. No seat back restraint provided.

4. Harness assembly: The harness assembly is secured by either the seat back retainer or strap and is free to move up or down on this section of webbing.

The specimens we have in for test are combinations of the above features and as such we would appreciate knowing what features are acceptable and which are not.

Should you require any additional information on this subject, in relation to the descriptions, please contact either Mr. H. D. Pomponio or myself.

Very truly yours,

C. F. Robb -- Manager, Automotive/Mechanical Division

ID: GF001071

Mr. David Regan
Trecan Combustion Limited
4049 St Margarets Bay Road
Hubley, Nova Scotia B3Z1C2
Canada

Dear Mr. Regan:

This responds to your February 10, 2004, letter and phone conversation with George Feygin of my staff. You ask whether snow melting machines manufactured by your company would be classified as "motor vehicles." You manufacture three different machines with the primary function of melting large quantities of snow. In order to move from location to location, these machines are equipped with wheels and function much like a trailer. As explained below, based on the information you provided us, we would not consider these machines to be motor vehicles for the purposes of our regulations.

Title 49 U.S.C Chapter 301 authorizes the National Highway Traffic Safety Administration (NHTSA) to prescribe Federal motor vehicle safety standards (FMVSSs) applicable to new motor vehicles and new items of motor vehicle equipment. Section 30102(a)(6) defines "motor vehicle" as:

"[A] vehicle driven or drawn by mechanical power and manufactured primarily for use on the public streets, roads, and highways, but does not include a vehicle operated only on a rail line."

NHTSA has issued several interpretations of this language. We have stated that vehicles equipped with tracks, agricultural equipment, and other vehicles incapable of highway travel are not motor vehicles. We have also determined that certain vehicles designed and sold solely for off-road use (e.g., airport runway vehicles and underground mining vehicles) are not motor vehicles, even if they may be operationally capable of highway travel. Finally, we have concluded that items of mobile construction equipment that use the highways only to move between job sites and that typically spend extended periods of time at a single site are not motor vehicles. However, we do consider vehicles that use the public roads on a necessary and recurring basis to be motor vehicles.

In the present case, your letter states that your snow melting machines are designed primarily for use by airports and other large facilities, such as parking garages. While these machines are capable of highways travel, you state that in all likelihood such travel will be limited to reaching permanent or semi-permanent job sites (i.e specific locations where large snow piles are continuously accumulated). Based on this information, it appears that these machines are akin to airport runway vehicles or items of mobile construction equipment that do not travel on highways on a recurring basis. Accordingly, we find that the snow melting machines described in your letter are not "motor vehicles." Because these machines are not motor vehicles, they are not subject to our regulations and requirements, including the requirement to meet all applicable FMVSSs.

We note that our finding is limited specifically to the equipment described in your letter, and is largely based on your representation of its intended use. In your correspondence, you state that some snow melting machines may be sold to large cities, but you do not elaborate further. We presume that snow melting machines purchased by large cities would also remain mostly at some single location designated for snow melting activities. However, we wish to caution that our finding does not apply to snow melting equipment that is intended to be used extensively on public roads on a recurring basis.

I hope you find this information helpful. If you have any other questions please contact Mr. George Feygin at (202) 366-2992.

Sincerely,

Jacqueline Glassman
Chief Counsel

ref:571
d.3/12/04

ID: GF006103

Larry C. Dickinson, Ph.D.
Manager, Engineering & Technology
Martin Marietta Composites
PO Box 30013
Raleigh, NC 27622

Dear Mr. Dickinson:

This responds to your phone conversation with George Feygin of my staff and subsequent e-mail asking whether Federal Motor Vehicle Safety Standard No. 223, Rear impact guards (FMVSS No. 223), S5.2.2 allows for "elastic deformation" as opposed to plastic deformation. Specifically, you ask whether the requirement that the energy absorption be accomplished by plastic deformation would preclude a material that returns to its original shape (i.e., elastic material).

By way of background, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to certify that their vehicles and equipment meet applicable requirements. The issues raised by your letter are addressed below.

FMVSS No. 223 requires that underride guards fitted to new trailers and semitrailers provide a certain amount of energy absorption to lessen the crash forces on a passenger vehicle colliding from the rear. In creating FMVSS No. 223, the agency sought to balance concerns associated with rear impact guards being overly rigid and non-yielding in rear impact crashes against those associated with the guards being insufficiently rigid to prevent intrusion of a trailer into a vehicle occupant compartment. Accordingly, the standard requires that a certain minimum amount of force be absorbed through "permanent yielding" or plastic deformation of the guard. [1] S5.2.2 of the standard states:

" [a] guard  . . .shall absorb by plastic deformation within the first 125 mm of deflection at least 5,650 J of energy at each test location P3."
(emphasis added).

The standards energy absorption requirement cannot be met by elastic deformation for two reasons. First, the language of the standard calls for plastic deformation. Second, the prescribed method of measuring the required energy absorption greatly restricts any elastic qualities of the rear impact guard. Specifically, any energy that the guard returns to the force application device when the load is removed (i.e., the elastic component of the deformation) is subtracted from the total energy absorption for purposes of meeting the requirement.

The requirement that guards absorb energy by plastic deformation was to ensure that the guard did not subsequently return the absorbed energy to the colliding vehicle, because that energy return could increase the chance of death or injury to the occupants. Any immediate rebound occurring after the crash event could pose a threat to passenger vehicle occupants.

In an August 4, 1998, letter to Mr. Toms of Power Brace (copy enclosed), NHTSA stated that the plastic deformation requirement of S5.2.2 does not preclude use of certain elastic materials that return to their original shape very slowly (approximately 24 hours). Based on your conversation with Mr. Feygin, it is our understanding that your question concerned materials that returned to their original shape immediately after impact.

I hope this information is helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992.

Sincerely,

Jacqueline Glassman
Chief Counsel

Enclosure
ref:223
d.10/21/03





---

[1] See Preamble to the Final Rule, January 24, 1996 (61 FR 2004 at 2011).

ID: nht80-1.10

DATE: 02/07/80

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Michelin Tire Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your November 16, 1979, letter in which you requested an interpretation of the requirements of Federal Motor Vehicle Safety Standard No. 109 (49 CFR @ 571.109). Specifically, you asked if it is permissible for a tire manufacturer to label its tires with information about other tire sizes which the labeled tire could be used to replace. For example, you stated that Michelin would like to label its tires with the alphanumeric tire size which its P-metric tire sizes could replace and that Michelin would like to label its 230-15 tires as replacements for the 225-15 tires. Such labeling is expressly prohibited by Standard No. 109.

Paragraph S4.3(a) of Standard No. 109 specifies that each tire shall be labeled with "one size designation, except that equivalent inch and metric size designations may be used." With respect to the alphanumeric sizes and the P-metric replacements and the 225-15 and 230-15 sizes, the suggested replacement sizes have different section widths and minimum size factors than the sizes they would be replacing. In other words, they are not equivalent size designations, and S4.3(a) prohibits the tire from containing more than one size designation in these circumstances.

Labeling of the sort you have requested has been commonly referred to as "dual-size markings." Dual-size markings are a representation that a particular tire can be considered as meeting fully the criteria of two separate tire size designations. In fact, such tires do not satisfy the physical dimension criteria in Standard No. 109 for both size designations. As a consequence, labeling of this type was specifically prohibited when the labeling requirements of Standard No. 109 were amended at 36 FR 1195, January 26, 1971. The prohibition has been repeated in subsequent notices which addressed the question of tire labeling under the Standard; see 39 FR 10162, March 18, 1974 and 42 FR 12869, March 7, 1977.

I should note that prohibition of dual-size markings does not mean that NHTSA believes that the replacement tires would perform inadequately if installed on the rims. However, dual-size markings represent a marketing effort by tire manufacturers to attempt to persuade consumers to change the size and/or type of tires mounted on their cars. It is inappropriate to extend this marketing effort to the Federally required label on the tire. The manufacturer must provide the consumer, in a straightforward manner, technical information necessary for the safety of the consumer's automobile. This should be the only purpose of the label.

Sincerely,

ATTACH.

MICHELIN TIRE CORPORATION -- Technical Group November 16, 1979

Office of the Chief Counsel -- National Highway Traffic Safety Administration, U. S. Department of Transportation

Ref: Federal Motor Vehicle Safety Standard 109

Gentlemen:

We are considering marking our P-series tires with the alpha-numeric size they replace shown below in parenthesis. An example would be as follows:

P205/75 R15 (replaces FR78-15)

Similarly, we are considering marking our 230-15 tire as follows:

230-15 (replaces 225-15)

The 230-15 can be used on all cars that are fitted with 225-15.

Please advise us if such markings would be in violation of FMVSS 109 or any other D.O.T. Standard.

Your quick response would be appreciated since we are planning to start these programs shortly.

Thank you.

Yours truly,

John B. White -- Engineering Manager, Technical Information Dept.

ID: Toyota_knee_bolster

Chris Tinto, Director, Technical & Regulatory Affairs
Toyota Motor North America, Inc.
1850 M Street, NW Suite 600
Washington, DC 20036

Dear Mr. Tinto:

This responds to your request for an interpretation regarding the definition of "air bag system" as it pertains to test procedures specified in our occupant crash protection standard. Your letter asked if an inflatable knee bolster would be considered part of the "driver frontal air bag system" under the procedure for low risk deployment (LRD) tests of the driver air bag. As explained below, for purposes of LRD tests, the driver frontal air bag system refers to the steering wheel hub-mounted inflatable restraint and does not include an inflatable knee bolster.

On May 12, 2000, the National Highway Traffic Safety Administration (NHTSA) amended Federal Motor Vehicle Safety Standard (FMVSS) No. 208 to minimize the risk of injury from deploying air bags for small adults and children (65 Federal Register 30680; Advanced air bag rule). The Advanced Air Bag Rule adopted a LRD test to address the risk air bags pose to out-of-position occupants, particularly those of small stature. The test is performed by activating a frontal air bag system with a test dummy in "worst case" positions: placing the dummys chin on the module and for the 5^th percentile adult female test dummy, also placing the dummy's chin on the steering wheel.

In your letter you stated that Toyota has equipped some of its vehicles with a knee air bag (knee bolster), which deploys in a frontal crash along with the driver air bag located in the steering wheel hub. You further stated that Toyota considers a knee bolster part of the frontal air bag system and therefore, it should be deployed during a LRD test. Your letter also noted that both the knee bolster and the air bag located in the steering wheel hub deploy in the rigid barrier test described in S22.5 of FMVSS No. 208, which determines the deployment stage for the LRD procedure in S26.

In a November 19, 2003, final rule, the agency specifically addressed which air bag system components are fired in a LRD test. The agency stated that:

While neither "air bag [system]" or "inflatable restraint [system]" is defined in FMVSS No. 208 or any other place in 49 CFR Part 571, the intent of the term "air bag" is to describe the components that make up the passenger- side dash-mounted and driver-side steering wheel hub-mounted, inflatable restraints used for occupant protection in a frontal impact. This does not refer to any other pyrotechnic system such as a belt pretensioner or inflatable knee bolster (68 Federal Register 65179, 65186; emphasis added).

We further stated that the agency has no data on the effect deploying devices other than the frontal air bag will have on the LRD test procedure. We also do not have any data on the performance of any of these other pyrotechnic devices for out-of-position occupants in the field. Specifically, we are concerned that inflatable knee bolsters could negatively impact the repeatability of the LRD tests, even though they would inflate in a real crash. Therefore, when the agency performs a LRD test on a vehicle equipped with inflatable knee bolsters, the knee bolsters are not inflated.

If you have any further questions, please contact Mr. Chris Calamita of my staff at (202) 366-2992.

Sincerely,

Jacqueline Glassman
Chief Counsel

ref:208
d.7/19/04