ID: aiam0404

Dear Mr. Wuddel: This is in reply to your letter of July 7, 1971, to the Nationa Highway Safety Bureau (now the National Highway Traffic Safety Administration) concerning the requirements for sealed beam headlamp units.; The answers to your specific questions are as follows: >>>1. Sealed beam units must meet the photometric specifications in SA J579 at the design voltage at or below the maximum amperes specified in SAE J573.; 2. Tolerances are as follows: *Electrical power* - the maximum electrical power is the product, i watts, of the design voltage multiplied by the maximum amperes at design volts. There is no specified minimum electrical power.; *Maximum amperes* - There is no tolerance. Maximum amperes is th maximum specified in SAE J573.; *Design watts* - There is no tolerance. There is, however, a toleranc on the actual watts or electrical power as described above.; 3. & 4. The filament types and positions are illustrative of curren practice only. Any type or position may be used to meet the specifications of J579 and J573.; 5. All glass sealed beam units are not mandatory. There are n restrictions in Federal Motor Vehicle Safety Standard No. 108 or the SAE Standards on the number of pieces or the materials which are used to complete the assembled sealed beam unit as long as the specifications, including those in SAE J571, are met. Caution should be used, however, to ensure that a good and durable seal is obtained between the metal back, if used, and the other parts to optimize the useful service life of the sealed beam unit.<<<; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs;

ID: aiam1716

Dear Mr. Henderson: This is in reply to your letter of October 17,1974, requesting ou opinion on whether a torso pad you wish to utilize in a newly-designed child seating system must conform to the requirements of paragraph S4.10.1 of Standard No. 213, 'Child Seating Systems' (49 CFR S 571.213). The enclosed description, diagrams, and pictures of the pad show that it is attached directly to the harness restraint of the seating system. You suggest that because it works with the restraint webbing, it provides a cushioning function more or less like deformable, force-distributing material. You also suggest that it falls under the exclusion for belt adjustment hardware.; In our view, based on the information you provide, the torso pad is rigid component of the child seating system, and is subject to the requirements for padding and minimum radii of paragraph S4.10.1. The fact that the pad is attached to the belt system does not alter this conclusion. Paragraph S4.10.1 refers to 'any rigid component,' and the torso shield must be evaluated as a component separately from the belt system or any other component. We have determined that rigid should be interpreted in its normal, dictionary sense, and it appears from the information you have provided that the torso pad by itself is rigid in nature.; We can neither agree that because the torso pad acts as a bel adjustment system it falls within the exemption for 'belt adjustment hardware.' That exemption is intended to apply only to traditional belt adjustment hardware mechanisms, which are generally completely integrated into the belt webbing and do not protrude from it.; Yours truly, Richard B. Dyson, Acting Chief Counsel

ID: aiam5042

"Dear Mr. Misorski: This responds to your letter of August 6, 1992 asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108. You write with reference to an amendment that became effective December 1, 1991, requiring a minimum of 12 square inches of lens area for rear stop or turn signals on vehicles over 80 inches wide, regardless of the separation between lamps. You request confirmation of your feeling that 'equipment manufactured prior to December 1, 1991 would be exempt from this ruling', and that 'it only applies to equipment that is manufactured after December 1, 1991.' You have asked for this interpretation to 'ensure compliance with our equipment fleet.' What the amendments require is that multipurpose passenger vehicles, buses, trucks, and trailers whose overall width is 80 inches or more, which are manufactured on and after December 1, 1991, be equipped with stop and turn signal lamps that meet the new requirements. Stop and turn signal lamps which were manufactured prior to that date that do not meet the new requirements are permissible to replace original equipment of the same type on vehicles manufactured before December 1, 1991, but they cannot be used as either original or replacement stop and turn signal lamps on vehicles manufactured on and after December 1, 1991. Furthermore, Standard No. 108 continues to allow manufacture and sale on and after December 1, 1991, of the old type of stop and turn signal lamps for replacement of original equipment on vehicles manufactured prior to December 1, 1991. I hope that this assists you with your compliance question. We shall be pleased to answer any further questions you may have. Sincerely, Paul Jackson Rice Chief Counsel";

ID: aiam2627

Dear Mr. White: This responds to Michelin's March 23, 1977, letter concerning it February 20, 1976 petition for reconsideration of Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. Your petition for reconsideration was responded to on February 7, 1977 (42 Fr 7140). By this letter, you attempt to resubmit your petition for reconsideration.; Petitions for reconsideration must be received by the agency within 3 days of the publication of a notice. Since the resubmission of your petition is untimely, it has been considered a petition for rulemaking as required by Part 553,35 of our regulations (Code of Federal Regulations, Volume 49). The National Highway Traffic Safety Administration (NHTSA) denies your requested rulemaking.; Your petition suggests that consumers will be confused by the tir label information if the vehicle is not equipped with the tires identified on the label. The agency has determined that confusion will be minimized by the use if the optional heading 'Suitable Tire-Rim Choice.'; Your petition raises a second problem concerning tires of identica size designations manufactured by different companies. These tires may have different inflation pressures even though their sizes are identical. The agency understands that this difference in inflation pressure could result in confusion. Manufacturers, however, con avoid this problem through the use of the manufacturers's name on the tire information label as part of the tire information. Use of the manufacturer's name on the label should distinguish between two otherwise similar tires.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs;

ID: 17385.wkm

Mr. William Daws
B & W Farm Center
7581 East Monroe Road (M-46)
Breckenridge, MI 48615

Dear Mr. Daws:

Please pardon the delay in responding to your letter to Walter Myers of my staff asking whether the antilock brake system (ABS) requirements of Federal Motor Vehicle Safety Standard (Standard) No. 121, Air brake systems (49 Code of Federal Regulations (CFR) 571.121), would apply to your truck glider kits. The answer is yes.

The agency's regulation with regard to the combination of new and used components is found at 49 CFR 571.7(e), Combining new and used components (copy enclosed), which provides in pertinent part:

When a new cab is used in the assembly of a truck, the truck will be considered newly manufactured . . . unless the engine, transmission, and drive axle(s)(as a minimum) of the assembled vehicle are not new, and at least two of these components were taken from the same vehicle.

By its terms, therefore, paragraph 571.7(e) applies to specific situations in which a new cab or body is combined with used chassis components. Stated another way, the resulting vehicle will constitute a new vehicle unless the engine, transmission, and drive axle(s)are used and any two of those component came from the same vehicle. If, on the other hand, either the engine, transmission, and/or drive axle(s) are new or no two of them are from the same vehicle, then the vehicle is new. If the vehicle is considered new, it must be certified to meet all applicable safety standards (including ones requiring ABS) in effect as of the date of its manufacture (not the date the vehicle was ordered or delivered). See 49 CFR Part 567.

You also asked whether a truck is required to meet the Federal motor vehicle safety standards even if approximately 80 percent of its use will be off-road, in this case, farm use. The answer is yes.

Chapter 301 of Title 49, U.S. Code (U.S.C.)(hereinafter Act) authorizes this agency to establish Federal motor vehicle safety standards (FMVSS) applicable to new motor vehicles and new items of motor vehicle equipment. The Act defines "motor vehicle" as:

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

49 U.S.C. 30102(a)(6).

We have interpreted this language as follows. Vehicles that are equipped with tracks or are otherwise incapable of highway travel are plainly not motor vehicles. Agricultural equipment, such as tractors, are not motor vehicles. Further, vehicles designed and sold solely for off-road use (e.g., airport runway vehicles and underground mining vehicles) are not considered motor vehicles, even though they may be operationally capable of highway travel. On the other hand, vehicles that use the public highways on a necessary and recurring basis are motor vehicles. For instance, utility vehicles like the Jeep are plainly motor vehicles, even though they are equipped with special features to permit off-road operation. If a vehicle's greatest use will be off-road, but it will spend a substantial amount of time on-road, NHTSA has interpreted the vehicle to be a "motor vehicle." Further, if a vehicle is readily usable on the public roads and is in fact used on the public roads by a substantial number of owners, NHTSA has found the vehicle to be a motor vehicle.

Nothing in your letter suggests that your trucks should be treated any differently from any other trucks, which are clearly motor vehicles. We note that a particular customer's planned use would not ordinarily affect whether a vehicle is considered to be a motor vehicle. Moreover, even if your particular customers' planned use were relevant, 20 percent would represent a substantial amount of time on-road.

I am also enclosing for your information fact sheets entitled Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment; Where to Obtain NHTSA's Safety Standards and Regulations; and Federal Requirements for Manufacturers of Trailers.

I hope this information is helpful to you. Should you have any further questions or need additional information, feel free to contact Mr. Myers of my staff at this address or at (202) 366-2992, fax (202) 366-3820.

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosures
ref:121#567#568#571
d.12/4/98

ID: 18065.nhf

Mr. Ron Smith
Vice-President
Access Wheels, Inc.
7101 North 55^th Avenue
Glendale, AZ 85301

Dear Mr. Smith:

This is in response to your letter in which you asked whether you are required to conduct impact crash tests as a prerequisite to complying with federal safety requirements. I apologize for the delay in my response. You explain that you modify minivans and full-size vans, both before and after the first retail sale, to accommodate persons with disabilities. The modifications you perform typically involve installing wheelchair lift mechanisms in full-size vans and wheelchair ramp assemblies in lowered floor minivans. You explain that you install various combinations of equipment acquired from a large number of manufacturers and suppliers in your modifications. You explain that you rely on an assortment of impact crash test data, other testing, and engineering analysis in determining whether the vehicle complies with the safety standards. You state that you believe you have exercised due care with respect to these determinations and compliance with all the applicable safety standards. In light of these circumstances, you have asked whether you are required to conduct multiple crash tests. As discussed below, Access Wheels is required to assure that each of the vehicles it manufactures complies with all applicable safety standards, but it is not required to conduct crash tests of any of its vehicles to certify compliance with these standards.

We would like to begin by explaining that the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. Manufacturers are required to certify that their products conform to our safety standards before they can be offered for sale. Federal law prohibits any person from manufacturing, introducing into interstate commerce, selling, or importing any new motor vehicle or item of motor vehicle equipment unless the vehicle or equipment item conforms to all applicable safety standards. NHTSA, however, does not approve motor vehicles or motor vehicle equipment items, nor does the agency endorse any commercial products or their vendors. Instead, the motor vehicle safety statutes, found in Chapter 301 of Title 49, U.S. Code, establish a self-certification process under which each manufacturer must certify that its products meet all applicable safety standards.

Each of the safety standards specifies performance requirements. Dynamic tests are prescribed under some of the standards, such as Standard No. 208, Occupant Crash Protection, and Standard No. 301, Fuel System Integrity. However, the agency does not require a manufacturer to test its products only in the manner specified in the safety standards. A manufacturer may choose any means of evaluating a vehicle or equipment item to determine whether it complies with the requirements of an applicable standard, provided that the manufacturer assures that the vehicle or equipment item will comply with the standard when tested by NHTSA.

According to 49 U.S.C. 30115, a person may not certify a vehicle as complying with all applicable safety standards "if, in exercising reasonable care, the person had reason to know the certification is false or misleading in a material respect." NHTSA has long said that it is unable to judge what efforts would constitute "reasonable care" in advance of the actual circumstance in which a noncompliance occurs. What constitutes "reasonable care" in a particular case depends on many factors, including such things as the limitations of current technology, the availability of test equipment, the size of the manufacturer, and above all, the diligence exercised by the manufacturer.

Since some of your modifications occur after the first sale of the vehicle to a consumer, you should also be aware of the statutory prohibition against making inoperative any device or element of design installed on or in a motor vehicle in compliance with an applicable standard. After the first sale of the vehicle, manufacturers, distributors, dealers, and repair businesses are prohibited from "knowingly making inoperative" any device or element of design installed on or in a motor vehicle in compliance with an applicable standard. In general, the "make inoperative" prohibition (49 U.S.C. 30122) requires businesses which modify motor vehicles to ensure that they do not remove, disconnect, or degrade the performance of safety equipment installed in compliance with an applicable standard. Violations of this prohibition are punishable by civil penalties of up to $1,100 per violation.

If you have any further questions regarding vehicle certification requirements or the safety standards, please contact Ms. Nicole Fradette of my staff at 202-366-2992.

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosure
d.10/22/98
ref:VSA

ID: 1982-3.36

TYPE: INTERPRETATION-NHTSA

DATE: 12/30/82

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Wonder Enterprise

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of November 22, 1982, asking whether Federal regulations would prohibit use of your patented device, the "Illuminated Wonder Panel." This device would be used in the space provided for the front license plate and consists of a panel on which numbers or letters would be illuminated from behind, if an owner wished to "personalize" his vehicle. You have indicated that the candela for each character averages .0365, and that with a seven character maximum, a total output of less than .25 candela would result You submitted photographs showing this device in operation from a distance of 50 feet on a vehicle using parking lamps only, and using parking lamps/low beam headlamps.

Your device is not directly regulated by the Federal motor vehicle safety standard on vehicle lighting, Standard No. 108 As an item of original equipment, your device is permissible unless it impairs the effectiveness of lighting equipment required by the standard, such as parking lamps and headlamps. Judging by the photographs you submitted, it does not appear that your device would impair the effectiveness of other lighting equipment. As an aftermarket item, your device is subject to regulation by any State in which the vehicle bearing it is registered. You will have to consult these States for further advice.

We hope that this is responsive to your request.

SINCERELY,

November 22, 1982

Robert Munoz Wonder Enterprise

Frank Burndt Chief Counsel National Highway Traffic Safety Administration

Dear Mr. Burndt:

I am a distributor that is interested in marketing a special type of lighting device for use on motor vehicles. This device is basically an illuminated personalized auto tag that is affixed to the front bumper of a car (for those states with single license plates). The tag, 6" x 12", will have personalized names or numbers on it, and only these letters or numbers will be illuminated; the rest of the tag will not emit light. This tag, registered in the U.S. Patent Office as the "Illuminated Wonder Panel", is no different than the current personalized automobile tags used in those states with single license plates, except that on this tag the personalized characters are illuminated.

The tag consists of a channel light housing that produces the incandescent light, an amber colored acylic panel thru which the light is emitted, and a clear cover plate. A prototype panel with the name "WONDER" in standard 2 inch letters, was submitted to a testing laboratory to measure the intensity of light produced (attached is the laboratory worksheet). The results showed an average of .0365 candela per letter or less than .25 candela total. With a maximum of seven characters on a tag, the intensity would never exceed .50 candela. Even though this is relatively minimal candlepower, I have enclosed two photographs taken of a vehicle at approximately 50 feet at night with the "WONDER" panel on the bumper, to illustrate the relative light intensities. Since the tag is designed to operate in conjunction with the lights, one picture is taken with the low beam headlights on, the other is taken with only the parking lights on.

The "Illuminated Wonder Panel" as described here, would be available as an automobile accessory; it is a form of ornamental lighting that to my knowledge is not defined by any SAE lighting standards or tests and may therefore not be regulated federally.

I believe this tag can be of value to the user and that the minimal light produced from the tag will not interfere with the intended operation of the existing vehicle's lights, or degrade the level of traffic safety while in its use. After speaking with Mr. Taylor Vinson and upon his suggestion, I am presenting this information to your Administration so that you may review it and advise me by providing a statement or opinion, in regards to its use prior to its production and distribution. Please let me know whether or not this would be in conflict with any safety standards and what subsequent procedures if any, need to be followed on a State level.

Thank you. I look forward to your response.

Robert Munoz President

ENVIRONMENTAL LAB WORK REQUEST OMITTED.

ID: nht94-2.68

TYPE: Interpretation-NHTSA

DATE: May 5, 1994

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Randolph Schwarz

TITLE: None

ATTACHMT: Attached to letter dated 9/30/93 Est. from Randolph Schwarz to John Messera (OCC-9211)

TEXT:

This responds to your letter to Mr. John Messera of NHTSA, requesting an interpretation of Federal Motor Vehicle Safety Standard No. 116; Motor vehicle brake fluids. Your letter has been referred to my office for a response. As a consumer retrofitting your vehicle with DOT 5 brake fluid, you had several questions concerning the possible effects that an ingredient in the brake fluid might have on elastomers used in brake systems. Your questions are answered below.

You described "seal swelling additives" added to DOT 5 brake fluid, that contact various elastomers in the brake system. Your first question was, when brake fluid manufacturers combine additives with brake fluid, should consumers be concerned with the c ombined fluids' compatibility with various elastomers used in braking systems?

Standard No. 116 defines, at S4. Definitions, brake fluid as a liquid designed for use in a motor vehicle hydraulic brake system where it will contact elastomeric components made of: styrene and butadiene rubber (SBR); ethylene and propylene rubber (EPR) ; polychlorophene (CR) brake hose inner tube stock; or natural rubber (NR). In order to minimize failures in hydraulic braking systems, Standard No. 116 specifies minimum performance standards for brake fluids. These performance standards include tests for styrene and butadiene rubber cups,the most common type of elastomer in a hydraulic brake system. The brake fluid manufacturer must certify that the brake fluid complies with Standard No. 116. (See S5.2.2(d).)

While DOT 5 brake fluid must meet Standard No. 116, the specific ingredients in the fluid are not regulated by the standard. However, in addition to compliance with Standard No. 116, brake fluid manufacturers must ensure that the fluid is free of safety -related defects under the National Traffic and Motor Vehicle Safety Act. Sections 151-159 of the Safety Act concern the recall and remedy of products with defects related to motor vehicle safety. In the event that the brake fluid manufacturer or NHTSA determines that the brake fluid contains a safety related defect, the brake fluid manufacturer would be responsible for notifying purchasers of the defective brake fluid and remedying the problem free of charge.

In your letter, you stated that you are retrofitting a vehicle with DOT 5 brake fluid. If your vehicle contained a brake fluid other than DOT 5 in its brake system, we recommend that the old fluid be flushed completely out of the brake system, before be ing replaced with DOT 5. This is necessary to ensure that the DOT 5 brake fluid does not mix with any other brake fluid type.

Your second question was whether DOT 5 brake fluid's compliance with

Standard No. 116 ensures compatibility with elastomers. The answer is yes, for SBR elastomers. Further, besides Standard No. 116, the brake fluid manufacturer is subject to sections 151-159 of the Safety Act, that were previously discussed. At this ti me, NHTSA is not aware of safety related defects resulting from other ingredients used with brake fluid.

Your third question was whether Standard No. 116 only addresses SBR compatibility with brake fluid. Standard No. 116, at S4, addresses brake fluid that contacts four elastomer types. However, the tests specified in the standard are only of the most com monly used SBR cups.

Your fourth question was, if Standard No. 116 only mentions SBR elastomer, would it be advisable to add other elastomers to the specification, or to discuss elastomer compatibility on the brake fluid container?

Information discussing the elastomer compatibility of the brake fluid, or other ingredients, may be voluntarily placed on brake fluid containers. Standard No. 116 specifies information that brake fluid containers must carry. However, Standard No. 116 do es not prohibit manufacturers from noting on brake fluid containers, compatibility of the silicone brake fluid, or other ingredients, with various elastomers.

Finally, you asked what Standard No. 116 specifies as the maximum viscosity for DOT 5 brake fluid, at -40 degrees Fahrenheit. Standard No. 116 specifies, at S5.1.3 (o), that the maximum viscosity is 900 centistokes (cSt).

I hope that this information is helpful. If you have any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992.

ID: nht93-6.29

DATE: September 2, 1993

FROM: Donald W. Vierimaa -- Vice President-Engineering, Truck Trailer Manufacturers Association

TO: John Womack -- Acting Chief Counsel, NHTSA

COPYEE: TTMA Engineering Committee; Tank Conference Engineering Committee; The 3M Company; Reflexite

TITLE: Conspicuity

ATTACHMT: Attached to letter dated 2/7/94 from John Womack to Donald W. Vierimaa (A42; Std. 108)

TEXT:

We request three interpretations pertaining to S5.7 of FMVSS 108.

Conversion from S1 to English linear dimensions

May we consider the following nominal English dimensions equivalent for the purpose of compliance with S5.7 of FMVSS 108?

FMVSS 108 English English Citation Item Metric (actual**) (nominal)

5.7.1.3(b) Length of 300 mm 11.8 inches 12 inches red or white +/- 150 mm +/- 5.9 inches +/- 6 inches block of (150 mm (5.9 inches (6 inches sheeting to 450 mm) to 17.7 in.) to 18 inches)

5.7.1.3(d) Width of Grade 50 mm min* 1.9 inches 2 inches DOT C2 sheeting

5.7.1.3(d) Width of Grade 75 mm min* 2.9 inches 3 inches DOT C3 sheeting

5.7.1.3(d) Width of Grade 100 mm min* 3.9 inches 4 inches DOT C4 sheeting

5.7.1.4(b) Edge of white 75 mm min. 2.9 inches 3 inches sheeting to any lamp

5.7.1.4(c) Edge of red 75 mm min. 2.9 inches 3 inches sheeting to an amber lamp

5.7.1.4.1(a) Height of 1.25 m 49.2 inches 49 inches horizontal sheeting on rear

5.7.1.4.1(b) Length of 300 mm min* 11.8 inches 12 inches sheeting in upper contours of trailer

5.7.1.4.2(a) Height of 1.25 m 49.2 inches 49 inches horizontal sheeting on side of trailer

5.7.1.4.2(b) Alternative 25 mm min* 0.98 inches 1 inch width of two strips of Grade DOT C2 sheeting and their separation 25 mm max 0.98 inches 1 inch

5.7.1.5 Sheeting 3 mm min 0.118 inches 1/8 (0.125) certification inch character height

5.7.1.5 Sheeting 300 mm max 11.8 inches 12 inches certification marking separation

5.7.2.2(b) Alternative 100 mm max 3.9 inches 4 inches reflex reflector center to center separation

5.7.2.3 Reflex 3 mm min 0.118 inches 1/8 (0.125) reflector inch certification character height

* Assumed to be minimum. ** Significant decimal places for comparison.

The nominal English dimensions without underlining would appear to be acceptable conversions since they exceed the minimum metric dimensions. The nominal English dimensions underlined would, however, exceed the metric maximum dimension.

SAE J1322 JUN85, "Preferred Conversion Values for Dimensions in Lighting - Inch-Pound Units/S1," describes how English units may be converted to S1 (metric) units, but does not describe how to convert S1 units to English Units.

Vertical Location of Rear and Side Sheeting Cargo tank trailers may have a "vertical" surface only at their "belt line" which may be as high as 90 inches (2.3 m) above the ground. Retroreflective sheeting could, however, be located much closer to the ground, but for some

cargo tank trailers this may place the sheeting on non-vertical surfaces. In our comment of March 31, 1992 to Docket No. 80-9; Notice 4 we stated that "it is not clear from the proposed rulemaking as to where retroreflective material should be placed on curved surfaces of tank and some dump trailers or angled surfaces of some dump trailers."

One manufacturer of retroreflective sheeting states that "the sheeting could be applied at a maximum angle of 30 degrees to the vertical." This manufacturer reports that "An angle greater than this provides less conspicuity as defined by NHTSA."

May retroreflective sheeting be located significantly higher than 1.25 m above the road surface if there is no vertical surface lower than this height without installing structure just for the sheeting?

Upper Contour Sheeting

May the horizontal and vertical sheeting to the right and left upper contours of the trailer body required per S5.7.1.4.1(b) be of the dimensions and location shown in the enclosed figures 1 through 5?

Since a number of trailer manufacturers are presently installing conspicuity treatments in accordance with S5.7 of FMVSS 108 as standard equipment or at the request of their customers, your timely response is desirable.

ID: nht93-4.4

DATE: May 19, 1993

FROM: Richard A. Zander -- Project Engineer, AlliedSignal Automotive Proving Grounds

TO: Office of Chief Council, NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 3/23/94 from John Womack to Richard A. Zander (A42; Std. 105)

TEXT:

I am writing to obtain your official interpretation of the following statement in 49 CFR 57, 105 Section S5.1.4.2(a) "each vehicle with GVWR of 10,000 lbs. or less shall be capable of making 5 fade stops (10 fade stops on the second test) from 60 mph at a deceleration not lower than 15 fpsps for each stop, followed by 5 fade stops at the maximum deceleration attainable from 5 to 15 fpsps."

I am requesting your official interpretation of the phrase "at a deceleration not lower than 15 fpsps for each stop." As further reference Section S7.11.2.1 states "Attain the required deceleration within 1 second and, as a minimum, maintain it for the remainder of the stopping time."

Within the industry, I know of three different interpretations of this statement, there could by more:

1. The average deceleration for the stop must be greater than 15 fpsps. The average deceleration is calculated from one second after the stop begins to a vehicle speed of 5 mph.

2. After 1 second the deceleration can not drop below 15 fpsps even for an instant. If the deceleration drops below 15 fpsps at any time it is considered a failure even if the average deceleration is greater than 15 fpsps. 3. The average deceleration for the stop must be greater than 15 fpsps and the deceleration must be greater than 15 fpsps for at least 75% of the stop excluding the first second of the stop.

In the "Laboratory procedures for FMVSS No. 105-83, TP-105-83-00, dated January 31, 1984, page 1.49, data sheet No. 1.16 for the fade stops, requests the following information for the deceleration "Average Sust Decel" see pages 1 and 2 of Attachment A. Therefore, it appears that NHTSA's interpretation of the statement "at a deceleration not lower than 15 fpsps for each stop" is "the average sustained deceleration."

Pages 3 & 4 of attachment A are a typical fade stops. The X axis is time and on the Y axis is deceleration and pedal force.

Interpretation ONE would consider these a pass because the average deceleration was greater than 15 fpsps and the pedal force did not exceed 150 lbs.

Interpretation TWO would consider these a fail because several data points fell below 15 fpsps. This interpretation appears to not consider the intent of the fade procedure. The intent being that a vehicle be capable of making multiple

high deceleration stops in a short period of time without drastic changes in effectiveness. Thus the recovery stops have a maximum and a minimum pedal force requirement based on the baseline check stops.

Maintaining an average deceleration of at least 15 fpsps insures adequate heat build up in the linings to determine if they will fade or drastically change effectiveness.

The deceleration could fall below 15 fpsps for short periods of time due to instrumentation noise or in stop fade which was not immediately compensated for by the driver. Interpretation THREE would consider these a pass because the average deceleration is greater than 15 fpsps and the deceleration is greater than 15 fpsps for 75% of the stop after the first one second.

Considering the intent of the fade procedure, the 75% requirement is not necessary to insure adequate heat build-up in the linings.

The NHTSA interpretation "average sustained deceleration" would also consider these a pass.

I am also requesting that you send the latest version of the test procedure for FMVSS No. 105 from the office of vehicle compliance. Please send to:

Richard Z. Zander Allied Signal Automotive Proving Grounds 3214 State Road 2 New Carlisle, IN 46552

Thank you for your time and effort to respond to my requests.

ATTACHMENT

Laboratory Procedures for Federal Motor Vehicle Safety Standard No. 105-83; TP-105-83-00; January 31, 1984. (Text omitted)