ID: nht70-1.6

DATE: 05/01/70

FROM: AUTHOR UNAVAILABLE; R. A. Diaz; NHTSA

TO: Donald B. Haaversen

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of March 9, 1970, to the National Highway Safety Bureau, concerning our Federal motor vehicle tire standards.

The only tire standard promulgated to date is Federal Motor Vehicle Safety Standard No. 109, "New Pneumatic Tires-Passenger Cars" which was effective January 1, 1968. This standard specifies minimum performance for size, strength, endurance, high speed laboratory testing and labeling. For your information, I have enclosed a copy of Standard No. 109 and No. 110 with amendments.

The replies to your specific questions are as follows:

1.Question: New American made tires have DOT load ranges, load capacity and inflation pressures molded into the sidewall. Is this required (that they be permanently marked), or is it sufficient to affix a temporary marking (such as a sticker) with this same information?

Response: Section S4.3 states that this information shall be permanently molded into or onto all new passenger car tires manufactured after August 1, 1968. If the tire was manufactured between January 1, 1968 and July 31, 1968 the labeling requirements may be met by use of a label or tag.

2. Question: How is load capacity information arrived at? Is it by manufacturer certification, government conducted tests, or some other method?

Response: The load/inflation schedule is calculated by use of empirical formulas and coordinated through the various Tire and(Illegible Word) Associations as well as the Society of Automotive Engineers.

3. Question: Is it necessary that these tires be subject to safety tests? These particular tires are already imported by another organization and may already have passed the necessary tests, if any.Response: The application of the "DOT recital to a tire, is the tire manufacturers self certification that his tire conforms to all the minimum performance standards of Federal Motor Vehicle Safety Standard No. 109.

I have also enclosed for your review and information the following data:

1. U.S. Customs Regulations for Importation of Motor Vehicles and Items of Motor Vehicle Equipment.

2. Automobiles Imported Into the United States.

ID: nht76-4.14

DATE: 07/23/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: White Motor Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to White Motor Corporation's April 26, 1976, question whether S5.3.3 and S5.3.4 of Standard No. 121, Air Brake Systems, require minimum brake chamber air pressures of 60 psi and 95 psi, respectively, or whether these air pressures are included in the sections only as "bench marks" on which to base specifications for minimum actuation and release timing in brake systems. Section S5.3.3 specifies in part:

. . . With an initial service reservoir system air pressure of 100 psi, the air pressure in each brake chamber shall, when measured from the first movement of the service brake control, reach 60 psi in not more than 0.45 seconds. . . .

Your understanding that S5.3.3 and S5.3.4 only specify the air pressures of 60 psi and 95 psi as the basis for timing requirements is correct. Neither value is intended as a requirement that the vehicle be designed to provide a certain level of brake chamber air pressure. The values were based on an understanding of the typical configuration of existing air brake systems at the time the final rule was issued.

In response to your request for interpretation of these sections in view of White's intent to use a lower air pressure than was commonly used in the past, the agency will utilize the stated 60-psi value or a value that is 70 percent of the maximum air pressure (measured by the NHTSA at the brake chamber), whichever is lower. In the case of release, the stated 95-psi value or the value that represents maximum air pressure (measured by the NHTSA at the brake chamber), whichever is lower, will be used. For purposes of this determination, the maximum air pressure in the brake chamber is that obtainable with full brake application when the pressure in the service reservoir is at 100 psi. Use of the maximum air pressure application timing would be unreasonable because of the decreased rate of air pressure build-up that occurs as the brake chambers reach maximum pressure.

The agency will issue an interpretive amendment to S5.3.3 and S5.3.4 to reflect this interpretation.

ID: nht90-2.15

TYPE: INTERPRETATION-NHTSA

DATE: 04/12/90

FROM: BARRY FELRICE ASSOCIATE ADMINISTRATOR FOR RULEMAKING

TO: STEPHEN P. WOOD -- ACTING CHIEF COUNSEL NHTSA

TITLE: ACTION: PORSCHE'S MODIFIED ANTITHEFT EXEMPTION

ATTACHMT: ATTACHED TO LETTER DATED 05/31/90 FROM BARRY FELRICE -- NHTSA TO MIKE LOVE -- PORSCHE, A 35 PART 543; LETTER DATED 03/30/90 FROM MIKE LOVE -- PORSCHE TO JERRY CURRY -- NHTSA ADMINISTRATOR ON 49 CFR PART 543 EXEMPTION

TEXT: On April 4, 1990, Porsche Cars North America, Inc. (Porsche) submitted a request for approval of a modification to the existing antitheft device for the exempted MY 1990 Porsche 911 and 928 carlines.

Rulemaking has reviewed the changes submitted by Porsche, and finds that the system activation process as described by Porsche would not undermine the device and that it would qualify for de minimis treatment. Porsche has changed the antitheft system by allowing it to additionally monitor the glove box for opening. This means that if the glove box is opened while the system is armed, the alarm will be activated. Previously, the antitheft system would only monitor the vehicle's doors, hood, hatc, igni tion switch, and removal of its radio.

The system's alarm control unit will now be integrated with the central locking and interior light control units to save space and to simplify the vehicle's electrical system. Porsche's antitheft system will also now have the capability to accept other inputs such as motion sensors, and improved diagnostic capability to enhance serviceability.

The new system will continue to be armed by locking either the driver or passenger door with the ignition key. The same points of entry will continue to be monitored by the system and the disabling and alarm features will remain the same. The new syste m will also continue to be as protected and tamper resistant as the current system.

As stated above, Rulemaking does not believe that these changes are significant enough to warrant submission of a full modification petition by Porsche and, therefore, would qualify for de minimis treatment. Accordingly, Rulemaking requests a letter gra nting the change to the antitheft system be forwarded to Porsche, pursuant to Part 543.9(j).

Attachment Letter from Porsche Cars North America, Inc.

ID: nht88-2.3

TYPE: INTERPRETATION-NHTSA

DATE: 04/20/88

FROM: GEORGE ZIOLO -- DOT PAPERWORK PROCESSOR

TO: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TITLE: HEADLAMP COMBINATIONS - REQUEST FOR CLARIFICATION, FMVSS 108

ATTACHMT: ATTACHED TO LETTER DATED 09/12/88 TO GEORGE ZIOLO FROM ERIKA Z JONES; REDBOOK A32, STANDARD 108;

TEXT: Dear Ms. Jones:

I assist graymarket automobile importers in conforming their vehicles.

Some foreign models come equipped with four headlamps two of which are 7" diameter and two 5 3/4" diameter.

My clients modify them by installing two Type 2D1 (7" dia) high & low beam units outboards, and two Type 1C1 (5 3/4" dia) high beam units inboards.

OVSC (NEF-32) rejects such installations because they are "nonconforming" "headlighting systems". It is my opinion that such rejection is without basis.

As I understand it, the FMVSS are "minimum standards". S4.1.1 confirms this by requiring that "...each vehicle...be equipped with at least the number of lamps...specified in Tables I and III,...."

My clients' installation of two Type 2D1 lamps satisfies the minimum requirement specified in Table III.

My clients' installation of two Type IC1 lamps in addition to the two Type 2D1 lamps is not counter to a "headlighting system" as I can find in the standard. In addition, S4.4 appears to permit such combination.

While it may have been necessary to ensure symmetry in headlighting systems combinations in motorcycles by way of S4.1.1.34, where Table III calls for only one lamp, such clarification relative to vehicles other than motorcycles is obviously not needed s ince symmetry in such will be natural.

I therefore kindly request that you determine whether or not FMVSS 108 allows lamp combinations as outlined above and advise me at your earliest convenience. The cited lamp combinations are desired by my clients for reasons of appearance. Also, modificat ion of such vehicles to delete the 2D1 (7") lamp in lieu of a 2C1 (5 3/4") lamp is costly, including replacement of the entire front grille.

Sincerely,

FEDERAL REGISTER VOL 52, NO 208 10/28/87 NHTSA 49 CFR PART 571 (DOCKERT 87-15 NOTICE 1) FEDERAL MOTOR VEHICLE SAFETY STANDARDS, VEHICLE CLASSIFICATION (TEXT OMITTED)

ID: nht88-2.96

TYPE: INTERPRETATION-NHTSA

DATE: 08/10/88

FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TO: STEPHEN BORKOWSKI

TITLE: NONE

ATTACHMT: LETTER DATED 06/24/88 TO ERIKA Z. JONES FROM STEPHEN BORKOWSKI, OCC - 2243

TEXT: Dear Mr. Borkowski:

This is in reply to your letter of June 24, 1988, asking about the legality of your "Bimmer Dimmer Safety Stop Light Concept". The concept has as its goal to lessen the chance of rear end collisions, by governing "the intensity of brake light brightness to indicate the degree of braking being applied to a vehicle."

Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices, and Associated Equipment governs the legality of your concept. SAE Standard J586c Stop Lamps, August 1970, has been incorporated by reference, and specifies appropriate photometric requirements. Paragraph S4.5.4 of Standard No. 108 requires in pertinent part that "the stoplamps on each vehicle shall be activated upon application of the service brakes". We believe that this means that the lamp shall display the intensity that is designed into it to meet the photometrics of J586c. The photometrics are expressed in terms of a minimum for each test point and while there is not a corresponding maximum for each point, there is an overall maximum for the lamp. Thus, a lamp of variab le intensity could fall below the minimum at one or more test points or exceed the overall maximum. This, of course, would result in a noncompliance with Standard No. 108.

The agency examined the problem of rear end collisions and concluded that the most appropriate way to address it was through the center highmounted stoplamp, required equipment on passenger cars manufactured on and after September 1, 1985. This is inten ded not only to reduce the incidence of rear end collisions but also their severity. We are interested in the possibility of further reductions in rear end collisions. Because your concept may be of interest to that Office, I am forwarding a copy of yo ur letter to the agency's Associate Administrator for Research and Development for such further correspondence as may be warranted. We appreciate your interest in motor vehicle safety.

Sincerely,

ID: 19283.ogm

E. Pluribus Law Firm, P.C.
P.O. Box 326
Leland, MI 49654

Re: FMVSS 209

Dear Sir or Madam:

This responds to your letter concerning the test requirements of Standard No. 209, Seat Belt Assemblies. Your questions relate to provisions addressing the performance of seat belt buckles under this safety standard. Specifically, you ask several questions about what you describe as the "partial engagement" provisions of Standard No. 209. Your seven questions, and our response to each question are provided below.

l. How does NHTSA define "partial engagement" under FMVSS 209 3.21 & 5.27?

ANSWER: We note that Standard No. 209 does not contain either section you refer to in your question. However, S4.3(g) and S5.2(g) of Standard No. 209, respectively, each use the phrase "partial engagement" in describing the minimum performance criteria and the test procedures for assessing buckle performance. Under S4.3, a seat belt buckle with a metal-to-metal buckle must separate when subjected to a force of not more than 22 newtons 95 pounds) or less when in any position of "partial engagement." The meaning of the phrase "partial engagement" is not defined in Standard No. 209 and has not been previously interpreted by NHTSA insofar as it applies to this particular standard. We believe that "partial engagement" is that position where the male end and the female receptacle of a seat belt assembly is neither fully engaged and latched nor fully disengaged. Therefore, the two components are partially engaged when the male end is inserted into the receptacle but has not been inserted to the point where the latching mechanism has closed.

2. Is "partial engagement" one of the phenomena which NHTSA is concerned about in the language of FMVSS 209 3.5 - "Buckle release mechanism shall be designed to minimize the possibility of accidental release"?

ANSWER: No. As used in this Standard, "partial engagement" is not a phenomenon but is a state in which the buckle assembly is placed to test the resistance of the assembly to separation or disengagement when it is not in the fully latched position. The requirement in S4.1(e) that buckle release mechanisms be designed to minimize the possibility of accidental release is intended to provide some assurance that buckles will not be inadvertently released once in the latched position.

3. Is it correct that FMVSS 209 3.21 preclude [sic] certification of any buckle which requires more that 5 lbs. to release from any position of partial engagement? Specific reference should be made to the language "a metal buckle shall separate when in any position of partial engagement by a force of not more than 5 pounds (2.3 Kg)" in interpreting this provision.

ANSWER: Again, we note that Standard No. 209 does not contain the section cited in your question. However, the language cited in your question is found in S4.3(g) of the Standard. If this is, in fact, that section that your question refers to, the answer is yes.

4. Assuming no testing of maximum engagement is required under FMVSS 209 5.27 if it is determined that partial engagement is not possible "by means of a technique representative of actual use", how important is it to conduct a fair and adequate test of "representative use?"

ANSWER: In answering this question, we assume that you are referring to S5.2(g) of Standard No. 209. In certifying compliance with a standard, manufacturers must make efforts to ensure that they have exercised due care. If the agency testing shows that an apparent noncompliance exists with a vehicle or item of equipment, the manufacturer is asked to show the basis for its certification that the vehicle or equipment complies with the relevant safety standard or standards. If there is a noncompliance, the manufacturer must conduct a recall campaign to remedy the problem. In addition, the manufacturer is subject to civil penalties unless it can establish that it exercised "due care" in the design and manufacture of the product and in the checks (through actual testing, computer simulation, engineering analyses, or other means) to ensure compliance, but nevertheless did not have reason to know that the vehicle or item of equipment did not comply with the safety standards.

5. What is a fair and adequate test to determine "whether partial engagement is possible by means of a technique representative of actual use" under FMVSS 209 5.27?

ANSWER: This agency has long stated that it is unable to judge what efforts would constitute "due care" in advance of the actual circumstances in which a noncompliance occurs. What constitutes "due care" in a particular case depends on all relevant facts, 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.

6. Would the NHTSA interpretations provided above be the same in 1988-91 as they have been provided in response to the request for interpretation herein.

ANSWER: Yes.

7. If the response to request No. 6 is negative, please identify all interpretations which would have been different and the underlying basis for the change in interpretation between 1988-91 and present.

ANSWER: See the answer to item 6 above.

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

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:209
d.7/8/2000

ID: 1985-01.10

TYPE: INTERPRETATION-NHTSA

DATE: 01/11/85

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHSTA

TO: Kazutoshi Kasagi -- Chief Inspector, International Trade and Industry Inspection Institute Ministry of International Trade and Industry (Japan)

TITLE: FMVSS INTERPRETATION

TEXT: Mr. Kazutoshi Kasagi Chief Inspector Internationally Agreed Safety Division International Trade & Industry Inspection Institute Ministry of International Trade & Industry Japanese Government 15-1, 6 Chome Ginza Chuo-ku Tokyo, Japan

This is in reply to your letter of November 13, 1984, with respect to interpretations of the motorcycle headlighting requirements of Federal Motor Vehicle Safety Standard No. 108, and SAE J584.

You have asked "whether other lighting systems than referred in S4.1.1.34, such as non-sealed beam head lamp with two bulbs, are acceptable or not." The answer is yes. Non-sealed lamps meeting the requirements of SAE J584 are acceptable, including those with two bulbs, as the "At-Focus Tests" paragraph of J584 is directed to "light source or sources."

Your next question is whether photometric compliance is judged when one light is on or two, including the maximum permissible output of 75,000 cd. The answer to this question depends on the design of the lamp; if it is designed so that both bulbs operate simultaneously, then photometrics including maximum output are determined with both bulbs operating. If the design is such that one bulb produces lower beam and the other the upper beam, then compliance is judged by that method of operation. Should one bulb produce both lower and upper beams and the other bulb perform an unregulated lighting function, then the photometric compliance would be judged with only the bulb used for the regulated function. In this case, however, the unregulated bulb must not interfere with the effectiveness of the headlamp. This also answers your final question about conduct of the out-of-focus test. It is to be conducted according to the design intent of the operation of the headlamp, i.e. the design function of each bulb or bulbs.

You have also asked about the geometrical center of a design when one of two bulbs (both with an upper beam and a lower beam filament apparently) is on. Operation of only one bulb alone would result in an assymetrical lighting display off the vehicle's centerline. This is permitted by S4.1.1.34 of Standard No. 108 for the sealed beam lighting systems specified therein. Therefore, we could not logically disapprove of it for unsealed headlighting systems. However, if only one bulb performed both the lower beam function and the upper beam, and the other bulb performed an unregulated lighting function, then the bulb providing the lower/upper the lower beam function and the upper beam, and the other bulb performed an unregulated lighting function, then the bulb providing the lower/upper beams must be located on the vehicle's vertical centerline.

If you have any further questions, we shall be happy to answer them.

Sincerely,

Frank Berndt Chief Counsel

November 13, 1984

Mr. Frank Berndt, Chief Counsel Office of Vehicle Safety Standards, National Highway Traffic Safety Administration, DOT, 400 Seventh Street, S.W., Washington, D.C. 20590, U.S.A.

Dear Mr. Frank Berndt:

This is to ask you about interpretation and applicability of FMVSS 108 and SAE J584(Motorcycle Headlamp). Before asking questions, I'm pleased to introduce our organization. International Trade and Industry Inspection Institute (ITIII) is an affiliated inspection organization of Ministry of International Trade and Industry, Japanese Government and has three main functions. ITIII itself conducts test and inspections of industrial products under the control of MITI and ITIII administrates private inspection organizations, consumer bodies and manufacturers in terms of inspection and test. ITIII also is involved in the drafting process of inspection standards and inspection method of industrial products. ITIII has been an approved laboratory of lighting equipments by American Association of Motor Vehicle Administrators (AAMVA) and we have regular visits of Mr. Bardel and Mr. Cardarelli from AAMVA. We keep close relations with AAMVA for many years.

Inquiry

FMVSS 108 S4. 1. 1.34 specifies acceptable lighting system of motor cycles. This arises the question of whether other lighting systems than referred in S4.1.1.34, such as non-sealed beam head lamp with two bulbs, are acceptable or not. If it is acceptable, we have three questions to ask you further with regard to SAE J584.

Question 1

Which case should non-sealed beam lamp comply with specified photometric value of SAE J584 either when one bulb is lighted on or two bulbs are on? How should we interpret the requirement of Maximum 75000 cd in each case?

Question 2

Which should be the case of geometrical center when one bulb is on as illustrated below?

"INSERT GRAPHIC"

Question 3

How should we conduct out of focus test of the applicable case asked in question 1?

I hope this contact will be the first step to create good relation with your organization and I appreciate your quick response to our question.

Best regards,

Kazutoshi Kasagi

Chief Inspector, Internationally Agreed Safety Division

ID: nht73-1.22

DATE: 09/25/73

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Thomas Built Buses, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letters of July 26 and August 7, 1973, requesting an opinion on the applicability of the emergency exit provisions (S5.3 to S5.5) of Motor Vehicle Safety Standard No. 217, "Bus Window Retention and Release" (49 CFR 571.217), to buses that are of the same design as "school buses," but which are not manufactured (they are not painted yellow, nor do they have warning devices) nor used as school buses. You ask further that the standard exempt prison buses.

We interpret the exemption for school buses to include buses similarly designed, without regard to their intended use. School bus is defined in 49 CFR 571.3 to mean,

"a bus designed primarily to carry children to and from school . . . ."

We are of the opinion that buses which share the same design as buses that clearly fall within the definition of "school bus" are school buses under Standard No. 217, and are therefore exempt from the emergency exit provisions of the standard. No modification of the standard is accordingly called for.

With respect to your request regarding prison buses, we are presently considering similar requests previously received, and plan to respond by notice published in the Federal Register in the near future.

Yours truly,

August 7, 1973

Robert L. Carter Associate Administrator for Vehicles U.S. Department of Transportation

Re: Motor Vehicle Safety Standard No. 217 Bus Window Retention and Release

Thomas Built Buses, Inc., High Point, North Carolina, a manufacturer of school bus bodies, respectfully petitions the Department of Transportation for a revision in wording of said Standard, particularly section S5.2.3 School Buses. We petition that the wording in this section be changed to read as follows: "The emergency exit requirements do not apply to school buses or buses of like design adapted for use for other than transporting children to and from school, but if such buses contain any pushout windows or other emergency exits, these exits shall conform to S5.3 through S5.5."

We base our petition on the fact that we as a body manufacturer do offer our base product design for other uses such as churches, activity buses for schools used for field trips and other school events, Boy Scouts, YMCA's, Salvation Army Clubs, etc. These units are constructed of the same basic design as what is termed a school bus but may vary as to color and omission of specific school bus safety warning systems. Our conclusion is that as the Standard is presently worded, it is a double Standard in that it states the Standard applies not to school buses but to those same buses if used for other than hauling children to and from school. We feel strongly that the Standard should apply to neither school buses or those of like design used by other groups or the Standard should apply to all buses including school buses. Due to the basic design of the product for school use, we are in agreement with the Standard as proposed but suggest the above additions.

In addition to the above, we respectfully submit to the Department of Transportation that prison buses which are vehicles manufactured to haul prisoners from one point to another, should not be included under this Standard. Prison buses should be exempt along with school buses and the others listed. The basis for this petition on prison buses is due to the fact that the Standard contradicts the specific purpose of a prison bus. In other words, prison buses are security vehicles with a minimum of escape possibility whereby the Standard increases escape possibility.

We would respectfully request your expediting a ruling on this petition since all body manufacturers have buses as described in this petition on order to build after September 1, 1973, and the effective date of said Standard is September 1, 1973. If further information is required by you, please advise us immediately.

Respectfully submitted,

James Tydings Chief Engineer

c.c. Berkley Sweet Executive Secretary School Bus Manufacturers Institute 5530 Wisconsin Avenue Washington, D. C. 20015

July 26, 1973

Berkley C. Sweet Truck Body & Equipment Association

Dear Mr. Sweet:

Kindly forward this letter to the Department of Transportation for the purpose of obtaining an interpretation on FMVSS #217 - Bus Window Retention and Release.

We request an interpretation on the definition of "School Bus" as applied to units which we sell to school bus route contractors. Many contractors use their buses for purposes other than just carrying school children. For example, they may carry a Sunday School class to the beach for a weekend. Will the requirement for a minimum number of emergency exits be applicable to a bus used in such a case?

We request that the "designated seating capacity" for a handicapped persons vehicle be taken as the number of wheelchair spaces plus the seated passenger capacity.

Are "School Activity Buses" required to have a minimum number of emergency exits? Such buses are used to carry sports teams to games and classes on field trips. These buses are owned by the schools and used because most states have laws that preclude the use of state owned route buses for such activities.

We request an exemption for buses which are sold to prisons on the basis that we sold less than 100 of them during 1972. We expect to sell approximately 30 such vehicles this year. Also, there is the reason of possible prison escape.

Thanking you in advance for your services, we remain

Very truly yours,

James Tydings Chief Engineer

ID: aiam4418

Dear Mr. Rossow: This responds to your request for an interpretation of Federal Moto Vehicle Safety Standard No. 121, *Air Brake Systems*. Section S6.2.1 of that standard specifies for certain tests conducted on a dynamometer that '(t)he dynamometer inertia for each wheel is equivalent to the load on the wheel with the axle loaded to its gross axle weight rating.' According to your letter, you have interpreted the term 'equivalent' in this section to 'authorize compliance testing by reference to axle loads under actual stopping conditions.' You requested confirmation of this interpretation. As discussed below, we disagree with your suggested interpretation.; By way of background information, the National Highway Traffic Safet Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with all applicable standards. The following represents our opinion based on the facts provided in your letter.; As indicated in your letter, your request for an interpretation wa submitted in light of recent correspondence between your company and NHTSA's Office of Vehicle Safety Compliance (OVSC). OVSC requested you to submit information on the compliance with Standard No. 121 of the Mercedes-Benz model L-1317, a two axle straight truck. You responded to that request by submitting a compliance certification and interpretation concerning section S6.2.1. In letter dated April 9, 1987, OVSC informed you that it did not agree with your interpretation.; Standard No. 121's dynamometer tests are set forth in section S5.4 That section specifies that brake assemblies must meet the requirements of S5.4.1 (brake retardation force--relevant only to towed vehicles), S5.4.2 (brake power), and S5.4.3 (brake recovery), under the conditions of S6.2. One of those conditions, set forth in S6.2.1, is as follows:; >>>S6.2.1 The dynamometer inertia for each wheel is equivalent to th load on the wheel with the axle loaded to its gross axle weight rating. For a vehicle having additional gross axle weight ratings specified for operation at reduced speeds, the GAWR used is that specified for a speed of 50 mph, or, at the option of the manufacturer, any speed greater than 50 mph.<<<; In support of your suggested interpretation, you noted that axle load of a decelerating vehicle vary under different deceleration conditions, i.e., as a vehicle travelling forward decelerates, the load on the axles shifts so that the front axle load rises and rear axle load falls. You stated that it is your reading of Standard No. 121 that the manufacturer 'can assess compliance by either using a static load value or determining which of the varying values of the axle load should be considered in view of actual vehicle behavior.' With respect to gross axle weight rating (GAWR), you suggested that when used in the context of Parts 567 and 568, the GAWR is properly measured in a static manner, to permit determination of whether the load carrying capacity of a vehicle axle in actual use has been reached. For dynamometer tests of service brakes under dynamic conditions, however, you argued that such tests should properly take into account the dynamic effects of deceleration.; You then stated the following: >>>The language of S6.2.1, setting dynamic test conditions, indicate that the dynamometer inertia for each wheel is to be set at the 'equivalent' to the load on the wheel, when the axle is loaded to its GAWR (i.e., its load-carrying capacity). This language is not restrictive and grants a manufacturer the flexibility of determining an 'equivalent' loading in consideration of the dynamic phenomena in conducting the tests required by S5.4. Thus, the static GAWR is permitted to be linked to dynamic conditions by the word 'equivalent.'<<<; We disagree with your suggested interpretation, which we believe i inconsistent with the language of S6.2.1, past interpretations of that provision, and the compliance test procedures the agency has long followed with respect to this provision. As indicated above, S6.2.1 specifies that the dynamometer inertia for each wheel is 'equivalent to the load on the wheel with the axle loaded to its gross axle weight rating.' The phrase 'equivalent to the load' uses the singular 'load,' instead of the plural 'loads,' to show that the dynamometer inertia has only a single value. By itself, this suggests that S6.2.1 was not intended to provide multiple options for the dynamometer inertia setting, depending on the dynamic conditions simulated.; Further, the overall language of S6.2.1 shows how the singl dynamometer inertia setting is to be determined. The term 'GAWR' is defined in 49 CFR Part 571.3 as 'the value specified by the vehicle manufacturer as the load-carrying capacity of a single axle system, as measured at the tire-ground interfaces.' When an axle is loaded to its load-carrying capacity, there is one 'load on the wheel,' at whose 'equivalent' the dynamometer inertia must be set.; While we believe that the language of section S6.2.1 is clear on th issue raised by your letter, we also note that agency guidance in the form of past interpretation letter and OVSC's laboratory procedures for Standard No. 121 are also clear. In an interpretation letter to Wagner Electric, dated May 26, 1972, the agency stated:; >>>In the dynamometer test conditions of S6.2.1, the dynamomete inertia for each brake assembly is based on 1/2 the GAWR of the axle. The rating for each axle is required to be stated separately. If, in the example you give, you choose to give 17,000 pounds as the rating for each axle, then the dynamometer inertia would be at 8,500 pounds for each brake assembly.; <<>>Section S5.1.1 does not specify whether or not the vehicle is movin as a test condition for the requirement. In view of the absence of this test condition, the NHTSA will resolve differences in this test condition in the manufacturer's favor if they affect the outcome of testing.<<<; We do not agree that this letter supports your suggeste interpretation. The letter addressed only the issue of how a requirement should be read in view of the absence of a particular test condition. As explained at length above, we conclude that section S6.2.1 clearly specifies the particular test conditions to be followed for this section. Therefore, the Oshkosh letter is not relevant to requests for interpretation of S6.2.1.; You also argued that in order to provide an appropriate braking system with proper distribution of brake forces between the axles, its design must take into account the transfer of weight from the rear axle to the front axle during normal and emergency braking conditions. You stated that such a design and compliance test leads to a significant reduction in premature lockup of the rear axle. You also argued that NHTSA has recognized your braking system as 'a safe and effective system' in its research testing.; We agree that a manufacturer must take into account the transfer o weight from the rear axle to the front axle when designing an appropriate braking system. This is necessary to provide safe brake performance during varying loading conditions, for normal and emergency brake applications on varying road conditions, and it is so for all kinds of vehicles. However, the requirements of Standard No. 121 do not require vehicles to have too much rear braking, as you appear to imply. The requirements of S5.4.2 (Brake Power), and S5.4.3 (Brake Recovery), are minimum performance requirements intended to help ensure that brakes retain adequate stopping capacity during and after exposure to conditions caused by prolonged or severe use, such as long, downhill driving. In practice, in order to perform well in such conditions, both front and rear brakes must have a minimum capacity, and this capacity is related to GAWR despite the fact that the actual loads borne by the front and rear axles vary during different brake applications. The agency therefore referred to GAWR in section S6.2.1, because this is an objective value that is readily ascertainable for every vehicle, and performance based on this value meets the particular safety need provided for by the requirements of section S5.4. These minimum requirements are not intended, nor do they operate, as a restriction on the design decisions that manufacturers must make independently to distribute braking capacity to meet anticipated load distributions.; Contrary to your assertion, NHTSA has not concluded that your brak system is 'safe and effective.' We also note that the quotations of the agency's research report cited in your letter address only limited aspects of braking performance and are taken out of context. We note that you stated that '(t)he Agency reported finding that the subject vehicle's front and rear axles were '. . .well balanced and tended to lock at close to the same pedal effort level.' (p. 19).' A more complete quotation is as follows:; >>>. . . In the empty driver best effort stops the driver was also abl to utilize this peak friction, although not as effectively as the antilock, because the brakes on front and rear axles of the vehicle were well balanced and tended to lock at close to the same pedal effort level. In the loaded case, however, the front axle tended to lock prematurely and it was not possible for the driver to maintain all four wheels near the peak friction level. He could keep the front tires near the peak but when this occurred rear braking was relatively low. If he applied more braking, the front axle locked and he lost steering control due to lack of lateral traction at the front tires.'<<<; Based on the information before the agency, OVSC is continuing it investigation concerning the compliance of your vehicles with Standard No. 121.; Sincerely, Erika Z. Jones, Chief Counsel

ID: 1124

Mr. Dennis G. Moore
President
Sierra Products, Inc.
1113 Greenville Road
Livermore, CA 94550

Dear Mr. Moore:

This responds to your letter of July 31, 1995, with respect to lens area requirements of amber turn signal lenses.

You believe that "by reducing the minimal area of the Amber Turn Signal light lens from 12 square inches to approximately 8 square inches or 6 square inches the U.S. would have more practical rules for U.S. Exports at no expense to Safety. You ask that, "If NHTSA's Legal Council feels this error should be corrected through the Petitioning Process, I ask that this writing be considered a `Petition for Change of FMVSS #108 Request'".

Standard No. 108 contains two relevant regulations, one applicable to vehicles whose overall width is less than 80 inches, and one to those whose overall width is 80 inches or more.

Under paragraph S5.1.1.26(a), the functional lighted lens area of a single turn signal lamp of either red or amber on a vehicle whose overall width is less than 80 inches shall be not less than 50 square centimeters. This is approximately 8 square inches. Therefore, no rulemaking is required to implement your recommendation.

The standard that applies to turn signal lamps on vehicles whose overall width is 80 inches or more is SAE Standard J1395 APR85, incorporated by reference in Standard No. 108. Under its paragraph 5.3.2, the functional lighted lens area of a single turn signal lamp shall be at least 75 square centimeters, or approximately 12 square inches. Therefore, rulemaking is required to implement your recommendation.

We are transmitting your letter to our Office of Safety Performance Standards for consideration as a petition for rulemaking to change the minimum lens area requirement for

turn signal lamps on large vehicles from 75 to 50 square centimeters. On September 4, 1995, I determined that your letter met our procedural requirements for a petition. Accordingly, the Office of Safety Performance Standards will inform you not later than January 1, 1996, whether your petition has been granted.

If you have any questions, you may refer them to Taylor Vinson of this Office (202-366-5263).

Sincerely,

John Womack Acting Chief Counsel ref:108 d:9/20/95