ID: nht72-2.19

DATE: 08/11/72

FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA

TO: Imperial Fire Apparatus

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of July 21 to Mr. (Illegible Words) Truck Body and Equipment Association, Inc., concerning interpretations of FMVSS No. 108 requirements relating to fire trucks.

The answers to the questions you asked are as follows:

I. Flashing Identification, Clearance, and (Illegible Word) Lights. (Illegible Word) calls for all identification clearance, and (Illegible Words) to be wired into a motor driven (Illegible Word) with a selector switch for "steady on" or "flashing". Is this procedure allowable?

(Illegible Word). Flashing side (Illegible Words), but not clearance and identification lamps, are permitted by FMVSS No. 108.

II. Flashing Lights.

Customer calls for a second set of identification and clearance lamps ((Illegible Words) and power) to be mounted adjacent to the existing lighting. This second set of lights is to be wired into a motor driven flasher with a separate control switch located in the cab. Is this procedure allowable?

Yes. The additional or supplemental lamps are permitted by FMVSS No. 108, and flashing these additional lamps is (Illegible Word) in non-compliance with the standard. Regulations of individual states may, however, be applicable to this arrangement.

III. Battery Disconnect Switch.

On many trucks, the battery is wired into a master switch whereby the battery can be completely isolated from the electrical system. When this switch is in the "off" position, all light switches including identification, clearance, and four (4) way hazard flashers become in-operative. With the vehicle's engine shut down, the four (4) way hazard signals may only be activated by turning (Illegible Word) to "on" and turning four (4) way hazard switch to "on". Is this installation in compliance with SAE (Illegible Words) 4.21. If there are lights that must be activated by a single driver action, could you please note them.

This installation is in compliance with the requirements of FMVSS No. 108, providing the master switch is separate from the ignition switch and the hazard warning signal lamps will flash with the master switch on and the ignition switch off.

ID: nht72-2.2

DATE: 02/23/72

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Cosco Household Products, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of January 12, 1972, concerning Motor Vehicle Safety Standard No. 213, "Child Seating Systems." You ask specific questions, enclosing 3 diagrams, regarding the application of certain provisions of the standard to a child seat you wish to build. You state that this seat in its present form is composed of a tubular steel frame, and has a molded plastic shell to seat the child, to provide head restraint, and to assist in containing the child under lateral decelerations.

You ask whether the shell is a rigid component, stating that it will most probably be manufactured of polyethylene of about .100 inch thickness, and will be deformable by hand. We believe that such a shell could be considered a non-rigid component. There is not at present a definition of "rigid" in the standard and manufacturers should rely on generally available definitions of the term in determining whether or not components are rigid.

You state further that in those areas where the shell contacts the tubular frame it is unquestionably rigid, and ask whether energy-absorbing material could be applied between the frame and the shell, rather than between the shell and the child as specified in S4.10 of the standard. In the particular case you present, it is not clear whether the rigidity of the shell is inherent or results because of its attachment to the frame. If by cushioning this attachment the rigidity will be eliminated, we would no longer consider the component to be rigid. However, the amount of cushioning needed would depend upon the amount necessary to eliminate the rigidity, and would not necessarily be the 1/2-inch thickness specified in S4.10 for covering rigid components. This determination would be for the manufacturer to make, based upon his analysis of when the rigidity has been removed from the component.

With reference to the question presented on sketch 1, we believe it is answered in the preceding paragraphs. Concerning sketch 2 you ask what the standard requires at point N, where there is "essentially no energy-absorbing material between the bottom of the groove and the rigid tube." S4.10 of the standard requires rigid components that may contact the head or torso, with certain exceptions, to be "covered" with energy-absorbing material having a thickness of at least 1/2 inch. If the point N with which you are concerned can contact the head or torso of the child during impact, taking into account compression of the material adjacent to it, then it must be covered with at least the specified thickness of energy-absorbing material.

Your third sketch asks whether energy-absorbing material is required where the shell loops over the tubular steel frame, when the side of the shell is greater than 24 square inches. You are apparently assuming that the area in question is contactable as that term is used in S4.10. In our view the answer to this question depends upon whether the part of the seat in question is actually a "side" and if so if its rigidity is uniform. If the area in question creates a frontal projection we would not consider it to be a "side" under S4.10. If it does not, but the side is significantly more rigid in the area of the tubular frame, then we would not consider the exemption in S4.10.3 to apply, since the shell would not be one component. The hazard created would be identical if the tubular frame were exposed, and not covered by the shell.

Finally, you ask for any information on the status of Notice 5, published September 23, 1970 (35 F.R. 14786). A final rule based on this notice is in preparation, and we expect that it will be issued in the near future. At the same time, we have placed in the docket a report entitled "Report of Test on Child Vehicles and Their Energy Absorbing Materials." This report summarizes recent test work done to investigate test procedures for head restraints and energy absorbing materials for child seats.

ID: nht72-2.20

DATE: 10/02/72

FROM: AUTHOR UNAVAILABLE; C. A. Baker for E. T. Driver; NHTSA

TO: The Grote Manufacturing Company

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of September 25 to Mr. Lewis C. Owen of this Office concerning the mounting of front clearance lamps on trucks and buses over 80 inches in width.

You are correct in your interpretation that these lamps must be mounted to indicate the overall width of the vehicle and as near the top as practicable. The width and height of the body in relation to that of the cab on a van type truck governs the proper location; therefore, each application must be judged individually. However, you are correct that the proper location should be the top front corners of the body when the height of the body is significantly higher than the cab.

Since this name question has been directed to us repeatedly and some manufacturers are installing cab mounted lights and others body mounted lights on quite similar vehicles, we anticipate that this aspect will be addressed in future rulemaking actions.

ID: nht72-2.21

DATE: 01/17/72

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

TO: Truck Body and Equipment Association, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of December 21, 1971, to Lawrence R. Schneider requesting an interpretation on the mounting of front identification lamps.

Standard No. 108 requires that identification lamps be mounted "as close as practicable to the top of the vehicle" (Table II). The "vehicle" is the vehicle as completed, and not the incomplete vehicle. Therefore, if the "top" of the vehicle, i.e., the highest point, is a location other than the cab, the identification lamps must be mounted at the "top", and not on the cab, if it is practicable to do so. Generally, manufacturers of van-body vehicles have found it practicable to mount identification lamps on the van body. Modified lighting diagram 0-1 which you enclosed originally depicted the correct location of identification lamps for a truck with a van body.

If the manufacturer of the cab portion of a truck has placed identification lamps on the cab, the lamps need not be removed when the lamps necessary for conformance are added at the "top."

Sincerely,

December 21, 1971 Mr.

Lawrence R. Schneider, Chief Counsel NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION U. S. Department of Transportation

Subject: REQUEST FOR INTERPRETATION ON MOUNTING HEIGHT OF FRONT IDENTIFICATION LAMPS.

Re: Lamps, Reflective Devices, and Associated Equipment Federal Motor Vehicle Safety Standard No. 108

The above referenced FMVSS No. 108, becoming effective January 1, 1972, establishes the location and mounting heights of the front identification lamps by stating-----

" . . . as close as practicable to the top of the vehicle . . ."

"On the front only-- and No part of the lamps or mountings shall extend below the top of the vehicle's windshield."

Insofar as trailers are concerned, identification lamps are not required on the front of the trailer. The reasoning for this is that the identification lamps stop the truck tractor will serve the requirement.

We shall use a typical van body truck as an example. (See attached Lighting Diagram O-1.) It is our contention that if identification lamps are mounted on top of chassis-cab vehicles--i.e. incomplete vehicles--as supplied by the chassis manufacturers, it is permissible to leave these lamps in place. We contend that it is not necessary to remove these chassis supplied lamps, nor is it necessary to add an additional set of identification lamps at the top of the body. Of course we realize that if there are not any identification lamps on top of the cab (vehicles 80 or more inches overall width), we would be held responsible to equip the truck with front identification lamps (as close as practicable to the top of the vehicle) as required by FMVSS No. 108.

Please advise us in writing if our interpretations are correct and in full compliance with FMVSS No. 108.

Your earliest response will be appreciated.

Very truly yours,

TRUCK BODY AND EQUIPMENT ASSOCIATION --

Paul A. Tatarski

Manager Engineering Services

Enclosure:

(Graphics omitted)

FOR VEHICLES OF 80 OR MORE INCHES OVERALL WIDTH

RECOMMENDED LAMP AND REFLECTOR LOCATIONS IN ACCORDANCE WITH THE FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 108

(DRAWING IS NOT TO SCALE)

The general areas indicated for lamps and reflectors are acceptable to the U.S. Department of Transportations National Highway Traffic Safety Administration and the Bureau of Motor Carrier Safety. Consult Federal MVSS No. 108 and the applicable tables therein for exact requirements such as: mounting height limitations lamp combinations and alternative locations.

LEGEND

1. Headlamps (2)-white (4 optional)

2. Front side-marker lamps (2)-amber

3. Front side reflectors (2)-amber

4. Front turn-signal lamps (2)-amber

4a. Front turn-signal lamps (2)-amber (optional location)

5. Front identification lamps (3)-amber 5a. Front identification lamps (3)-amber (optional location)

6. Front clearance lamps (2)-amber

7. Rear side-marker lamps (2)-amber

8. Rear side reflectors (2)-red

9. Rear identification lamps (3)-red

10. Rear clearance lamps (2)-red

11. Rear reflectors (2)-red

12. Rear stop-tail & turn-signal lamps (2)-red

13. Rear licence plate lamp (1)-white

14. Rear backup lamp (1)-white (location optional provided optical requirements are met)

15. Intermediate side-marker lamps (2)-amber (if vehicle is 30' or more overall length)

16. Intermediate side reflectors (2)-amber (if vehicle is 30' or more overall length)

NOTE

LAMPS AND REFLECTORS MAY BE MOUNTED AT OTHER PRACTICABLE LOCATIONS PROVIDED LOCATION AND VISIBILITY REQUIREMENTS OF FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 108 ARE MET.

Lighting Diagram

Supplement 1/1/71

ID: nht72-2.22

DATE: 02/18/72

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

TO: FMC Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to the questions you ask in your letter of January 7 concerning the Federal Motor Vehicle Safety Standards.

In your first question you ask whether a vehicular hazard warning signal operating unit must conform to SAE Recommended Practice J910 specified in Table 1 of Standard No. 106, or to the newer SAE J910s. The answer is J910; the revision J910a cannot become a requirement of Standard No. 103 without ruleasking action by this agency. As of (Illegible Words) has issued no proposal that (Illegible Word) be adopted. You also ask whether hazard lamps at both ends of the vehicle must flash simultaneously. The operating unit is defined in (Illegible Word) as a device "which causes all turn signal lamps to flash simultaneously . . ." This means that all turn signal lamps must flash on the same cycle, and that separate cycles for froat and rear turn signal lamps are not permissible.

In answer to your second question, Standard No. 108 does not yet specify requirements for side turn signal lamps, and thus does not prohibit their use on your motor home. As indicated in our "Program Plan for Motor Vehicle Safety Standards," October 1971, this agency intends to issue a notice in the near future proposing to incorporate requirements for side turn signal lamps in Standard No. 108

Finally you ask whether Standard No. 101 requires illumination (Illegible Words) handlamp switch with park ponition to operate clearance, I.D., and the marker lamps. Standard No. 101 does not require illumination of the headlamp switch, even if the switch does (Illegible Word) is the operation of other lamps whose controls, if separate, would have to be illuminated.

ID: GF006332

Mr. Timothy C. Murphy
Vice President, Engineering
Peterson Manufacturing Company
4200 East 135^th Street
Grandview, MO 64030

Dear Mr. Murphy:

This responds to your letter dated August 18, 2004, asking whether strobing stop lamps or auxiliary lamps are permissible under the requirements of Federal motor vehicle safety standard (FMVSS) No. 108.

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.

The Federal standard applicable to lighting equipment, including stop lamps, is FMVSS No. 108, Lamps, Reflective Devices and Associated Equipment. The relevant sections of that standard read as follows:

S5.5.10 The wiring requirements for lighting equipment in use are:

(a) Turn signal lamps, hazard warning signal lamps, and school bus warning lamps shall be wired to flash;

(b) Headlamps and side marker lamps may be wired to flash for signaling purposes;

(c) A motorcycle headlamp may be wired to allow either its upper beam or its lower beam, but not both, to modulate from a higher intensity to a lower intensity in accordance with section S5.6;

(d) All other lamps shall be wired to be steady-burning. [emphasis added]

In short, S5.5.10(d) of FMVSS No. 108 mandates that all lamps be steady burning, unless otherwise explicitly permitted.In the present case, stop lamps do not fall under any exception enumerated in S5.5.10 (a) through (c).Accordingly, FMVSS No. 108 requires stop lamps to be steady burning. We regard a strobe lamp as one that flashes. For this reason, the strobing stop lamps described in your letter would be prohibited by FMVSS No. 108, if they are installed as original equipment on motor vehicles.They would also be prohibited from being sold as replacement for original equipment stop lamps.Further, unless auxiliary lamps mentioned in your letter fall under any exception enumerated in S5.5.10 (a) through (c), they must also be steady burning.

This prohibition would also apply to aftermarket lighting installation because 49 U.S.C. 30122 prohibits manufacturers, dealers, distributors, and motor vehicle repair businesses from making inoperative safety equipment installed in accordance with FMVSS No. 108 (and any other applicable FMVSS as well).Accordingly, installation of a strobing lamp not permitted by S5.5.10 would create a noncompliance with FMVSS No. 108 which constitutes "making inoperative" within the meaning of the statute.

The list of persons prohibited from making vehicle modifications affecting compliance in 49 U.S.C. 30122 does not include vehicle owners.

I hope you find this information 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

ref:108
d.11/1/04

ID: GF006472

Mr. Jim Haigh
Vice President
Transpec Worldwide
7205 Sterling Ponds Ct.
Sterling Heights, MI 48312




Dear Mr. Haigh:

This responds to your e-mail regarding installation of certain auxiliary lighting on school buses. Specifically, you ask whether installing a "Driver Alert Device" on school buses, which you state has been mandated by the State of Alabama, conflicts with Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, reflective devices and associated equipment.

Your e-mail and your web site (www.transpecworldwide.com/products/driver_alert.htm) explain that the "Driver Alert Device" is an LED message board mounted on the school bus emergency door that is wired to flash the word "Caution" when the school bus is backing up. The device is also wired into the eight-lamp school bus warning lamp system. When the amber lamps of the system are activated, the LED sign alternately flashes "Caution-Stopping". When the red lamps of the system are activated, the sign flashes "Stop" or "Do not Pass".

First, S5.5.10 of FMVSS No. 108 generally requires that all lamps, including auxiliary lighting, must be steady burning, unless otherwise specifically permitted. Your message board does not fall under any exception enumerated in S5.5.10.

Second, S5.1.3 of FMVSS No. 108 prohibits additional lighting devices that impair the effectiveness of lamps required by FMVSS No. 108. The agency interprets the standard as generally prohibiting electronic message boards because they have the potential of impairing the effectiveness of required lighting (see August 4, 1997 letter to Mr. Alan Robinson).

However, with respect to school buses equipped with flashing electronic message boards, we do not prohibit them because we believe that under certain local conditions, an electronic message board could enhance the safety of school bus passengers. That is, we defer to the States with respect to the narrow issue of prescribing or prohibiting electronic message boards on school buses.

We caution that this interpretation is limited to electronic message boards on school buses. For example, the agency recently explained that our standards would prohibit a flashing red lamp located on the roof of a school bus, because it had the potential of impairing the effectiveness of the required lighting (see 5/22/03 letter to J. Adam Krugh IV). Further, electronic message boards must be located far enough away from the required lighting so as to minimize any potential impairment.

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

Sincerely,

Stephen P. Wood
Acting Chief Counsel

2 Enclosures

NCC-112:Gfeygin:mar:11/2/05:62992:OCC 006472
Cc: NCC-110 Subj/Chron, Docket Std. 108
S:\INTERP\108\GF006472.doc

ID: GF006474

Mr. Michael Kastner
Director of Government Relations
National Truck Equipment Association
1300 19^th Street, NW, 5^th Floor
Washington, DC 20036-1609




Dear Mr. Kastner:

This is in response to your letter in which you requested an interpretation of the new tire information requirements in S4.3.3 of the Federal Motor Vehicle Safety Standard (FMVSS) No. 110, Tire selection and rims for motor vehicles with a GVWR of 4536 kilograms (10,000 pounds) or less. Specifically, you ask if the tire and rim information specified in S4.3.3 of FMVSS No. 110 could be set forth separately from the certification label. As discussed below, the answer is no. However, as we have indicated in the past, it is permissible to provide a certification label in two parts under certain circumstances.

S4.3.3 reads (with emphasis added) as follows:

Additional labeling information for vehicles other than passenger cars.Each vehicle shall show the size designation and, if applicable, the type designation of rims (not necessarily those on the vehicle) appropriate for the tire appropriate for use on that vehicle, including the tire installed as original equipment on the vehicle by the vehicle manufacturer, after each GAWR listed on the certification label required by 567.4 or 567.5 of this chapter. This information shall be in the English language, lettered in block capitals and numerals not less than 2.4 millimeters high and in the following format:

Truck ExampleSuitable Tire-Rim Choice

GVWR: 2,441 kilograms (5381 pounds).

GAWR: Front1,299 kilograms (2,864 pounds) with P265/70R16 tires, 16 8.0 rims at 248 kPa (36 psi) cold single.

GAWR: Rear1,299 kilograms (2,864 pounds) with P265/70R16 tires, 16 8.00 rims, at 248 kPa (36 psi) cold single.

The information required by S4.3.3 thus cannot appear separately from the certification label.

We note, however, that as we explained in a May 3, 1984, letter to Takeshi Tanuma of Nissan, NHTSA permits the use of a certification label in two parts, under certain circumstances. We explained that while the Part 567 certification regulations specify that "a label" must be used, the agency has permitted the use of a label in two parts in circumstances which will not lead to confusion and which will satisfy the basic intent of Part 567. Specifically, the two portions of the label must be placed in close proximity to each other, to permit individuals to readily find all the specified information and to leave no doubt as to the significance of either portion of the label. Further, the two portions must be oriented in such a manner that the specified information appears in the required order. As a practical matter, these considerations require that the two portions be affixed to the same vehicle part. While the agency did not specify a particular distance as a maximum permissible separation of the two portions of the label, we stated that the two portions must be located so as to leave the unmistakable impression that they provide related information.

Accordingly, the information required by S4.3.3 cannot be separated from the certification label. However, the certification label may be affixed in two parts under the circumstances described above.

We note that the information required by S4.3.3 cannot be added to the tire information placard required by S4.3 of FMVSS No. 110. As the agency previously explained in amending the tire safety information regulations, additional information is not appropriate because it would overcrowd the already content-rich vehicle placard (see 69 FR 31306 at 31311).

Finally, we note that in the end of your letter, you requested that, if a separate label is not permitted, the agency treat your letter as a request for rulemaking to amend FMVSS No. 110 in order to afford vehicle manufacturers the option of specifying alternative tire and rim information separately from the certification label. However, your letter did not provide sufficient supporting information for us to determine whether rulemaking would be warranted.

If, after reviewing this letter, you still believe that rulemaking is needed, please submit a petition for rulemaking with detailed supporting information. Among other things, the agency would want to examine actual examples (photographs) of vehicles unable to display the information required by S4.3.3 on the usual certification label or a split certification label. We would also want to review additional information about spacing problems, and what location requirements might be appropriate for an additional label.

I hope you find this information helpful. If you have further questions, you may contact Mr. George Feygin of my staff at (202) 366-2992.

Sincerely,

Stephen P. Wood
Acting Chief Counsel

ref:110
d.11/16/05

ID: GF006496

Mr. Merrill Sutton
Tie Down Engineering, Inc.
5901 Wheaton Drive
Atlanta, GA 30336

Dear Mr. Sutton:

This responds to your facsimile and subsequent phone conversation with George Feygin of my staff regarding the possibility of placing your companys name on "side two" of brake hoses manufactured by Meiji Rubber and Chemical, Ltd. (Meiji). You indicated that Meiji is duly registered with the U.S. Department of Transportation (DOT) as a brake hose manufacturer. Further, Meiji is prepared to place your name, as a distributor, on "side two" of the brake hose.

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.

Federal Motor Vehicle Safety Standard No. 106 (FMVSS No. 106) has certain labeling requirements. S5.2.1 of the standard states:

S5.2.1 Each hydraulic brake hose shall have at least two clearly identifiable stripes of at least one-sixteenth of an inch in width, placed on opposite sides of the brake hose parallel to its longitudinal axis. One stripe may be interrupted by the information required by S5.2.2, and the other stripe may be interrupted by additional information at the manufacturer's option." (Emphasis added.)

Based on the language of the standard, Meiji, as a manufacturer of brake hoses, is permitted to enter "additional information" on the other side of the brake hose at its option. Such "additional information" can include, among other things, the name of your company.

We note that one side (or "side one") of the brake hose must contain information as required by S5.2.2. Specifically, the one side of the brake hose must include: (a) the symbol DOT; (b) a designation that identifies the manufacturer of the hose; (c) the nominal inside diameter of the hose; (d) the month, day and year of manufacture; [1] and (e) either "HR" to indicate regular-expansion hydraulic hose or "HL" to indicate low-expansion hydraulic hose.

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:106
d.10/9/03





---

[1] Your facsimile contained drawings of the brake hose in question. We note that the drawing of "side one" of the brake hose contains only the month and year of the manufacture but not the date.

ID: GF006498

Mr. Jack W. DeYoung
Tumbleweed Trucks, Inc.
318 Kwanzan Drive
Lynden, WA 98264

Dear Mr. DeYoung:

This responds to your facsimile dated August 29, 2003, seeking further clarification of our interpretation letter sent to you on August 7, 2003. In response to our August 7^th letter, you have reprogrammed the flash rate in your hazard warning signal flasher. You now ask whether the newly reprogrammed flash rate complies with the requirements of Federal Motor Vehicle Safety Standard No. 108 (Standard No. 108).

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.

As previously discussed, SAE Recommended Practice J945, "Vehicular Hazard Warning Signal Flasher," February 1966 (SAE 945), is incorporated by reference in Standard No. 108, as the Federal Requirement for Flashers. Paragraph 3 of J945 and its accompanying Figure 1 specify requirements for "Flash Rate and Percent Current On Time." The flash rate must be 60 to 120 flashes per minute for "normally open" (i.e., variable load) flashers, and 90 to 120 flashes per minute for "normally closed" (i.e., fixed load) flashers. This paragraph also specifies that:

"flashing rate . . . shall be measured after the flashers have been operating for a minimum of five consecutive cycles and shall be an average of at least three consecutive cycles." (emphasis added)

Your newly reprogrammed flash pattern operates as follows (in milliseconds):

ON	OFF	ON	OFF	ON	OFF
200	250	200	250	200	850

Our calculations indicate that the above flash pattern, taking into account the averaging procedure set forth in J945, is within the specified flash rate.

In considering this issue further, however, we believe this type of flash pattern is very different from what NHTSA contemplated in incorporating J945 by reference in Standard No. 108. As you know, existing flashers operate at an essentially constant rate. Moreover, while Figure 1 of J945 permits considerable flexibility in flash rate, our calculations indicate that the flash rate and percent current on time for each and every cycle of your flash pattern fall outside the figure.

As we have stated before, we believe that motor vehicle safety is best promoted by standardization of lighting signals. The information currently provided by signal lamps, such as flashers, is well understood by the driving public, instantly recognized, and unambiguously informative. We are concerned that very different flash patterns have the potential to cause confusion. Therefore, we plan in the near future to modify Standard No. 108 in a way that would preclude your design.

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

ref:108
d.4/2/04