ID: 2346y

Mr. R.M. Cooper
Vice President, Engineering
Gillig Corporation
Box 3008
Hayward, CA 94540-3008

Dear Mr. Cooper:

This responds to your letter asking this agency to consider a problem your company faces with respect to Standard 217, Bus Window Retention and Release (49 CFR 571.217). More specifically, you asked how some of your buses could be certified as complying with the emergency exit labeling requirements set forth in Standard 217 for buses other than school buses. I apologize for the delay in this response.

Paragraph S5.5.1 of Standard 217 provides that, in buses other than school buses, each push-out window or other emergency exit shall have the designation "Emergency Exit" followed by concise operating instructions, describing each motion necessary to unlatch and open the exit, located within 6 inches of the release mechanism. The purpose of this requirement is to identify for bus occupants the location and explain the use of specially-installed emergency exits. As I understand your letter, you have no difficulties providing appropriate instructions in the specified location.

Paragraph S5.5.1 continues with the following language:

When a release mechanism is not located within an occupant space of an adjacent seat, a label...that indicates the location of the nearest release mechanism shall be placed within the occupant space.

The terms "adjacent seat" and "occupant space" are defined in S4 of Standard 217 as follows:

"Adjacent seat" means a designated seating position located so that some portion of its occupant space is not more than 10 inches from an emergency exit, for a distance of at least 15 inches measured horizontally and parallel to the exit.

"Occupant space" means the space directly above the seat and footwell, bounded vertically by the ceiling and horizontally by the normally positioned seat back and the nearest obstruction of occupant motion in the direction the seat faces.

You stated that many of your buses have seats that face the aisle and that back up against windows designated as emergency exits. These aisle-facing seats are "adjacent seats" with respect to the emergency exits. The release mechanism for the emergency exit is not within the "occupant space" for these aisle-facing seats, since the release mechanisms are behind, not above, these seats. You enclosed a group of photographs to further illustrate this situation.

Since the release mechanism for the emergency exit is not within the occupant space of these adjacent aisle-facing seats, paragraph S5.5.1 of Standard 217 requires a label indicating the location of the release mechanism for the emergency exit to be placed within the occupant space for these seats. You have noted that the occupant space for these seats does not include any place to which this label could be attached. The nearest obstruction of occupant motion in the direction the aisle-facing seats face is the aisle facing seat on the opposite side of the bus. There are no intervening objects other than narrow vertical stanchions in the center of the aisle. Additionally, you suggested that placing the label on the floor or ceiling of the bus would not serve the purposes of this requirement, since those locations would not be readily visible to the seated occupant in an emergency situation.

In response to your letter, we have carefully considered the labeling requirements of S5.5.1 as they apply to aisle-facing seats in front of windows that serve as emergency exits. The final rule adopting this additional labeling requirement explained that NHTSA was concerned that an occupant of an adjacent seat might hinder egress through an emergency exit if the occupant did not know how to use the emergency exit. See 37 FR 9394, at 9395; May 10, 1972. In instances in which the release mechanism itself is not within the occupant space of an adjacent seat, a label within the occupant space directing the occupant of the seat to the emergency exit instructions will help reduce the likelihood that the occupants would inadvertently obstruct egress through the emergency exits.

NHTSA's goal of minimizing the likelihood of inadvertent obstruction of emergency exits is equally applicable to forward-facing and aisle-facing seats. However, the means of achieving that goal (i.e., placing a label within the occupant space of an adjacent seat, if the release mechanism is not within that occupant space) may not be equally successful for forward-facing and aisle-facing seats. The agency did not focus upon aisle-facing seats when it adopted this labeling requirement. With respect to forward-facing seats, it is relatively simple to locate a label within the occupant space that will be readily visible both to seated occupants and to persons standing in the aisle, as required by S5.5.2. However, with respect to aisle-facing seats, there may not be any location within the occupant space of such seats where a label could be placed so that the label would be visible to occupants of the seat and to persons standing in the aisle. If the labels were not visible in an emergency, such labels would not further NHTSA's goal of minimizing inadvertent obstruction of emergency exits.

Accordingly, we plan to issue a notice proposing to amend and clarify the requirements of S5.5.1 of Standard 217 as they apply to aisle-facing seats. Please note that, unless and until a final rule amending S5.5.1 of Standard 217 becomes effective, the current requirements of S5.5.1 remain in effect for aisle-facing seats. However, the agency believes that it would be inappropriate at this time to enforce the requirement in S5.5.1 that additional information be labeled within the occupant space of aisle-facing seats given the uncertainty that such labels will serve the purpose for which the labeling requirements were established, as noted above. Accordingly, until the agency makes a final decision on the proposed rulemaking mentioned above, NHTSA will not take any enforcement actions against bus manufacturers that do not place a label indicating the location of the nearest emergency exit release mechanism within the occupant space of adjacent aisle-facing seats.

Sincerely,

Stephen P. Wood Acting Chief Counsel

/ref:217 d:3/20/90

ID: nht87-1.33

TYPE: INTERPRETATION-NHTSA

DATE: 02/20/87

FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA

TO: Bruce Torrey -- Product Performance Specialist, General Electric Company

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. Bruce Torrey Product Performance Specialist General Electric Company One Plastics Avenue Pittsfield, MA 01201

Thank you for your letters of August 13, and 26, 1986, concerning how the requirements of Standard No. 205, Glazing Materials, apply to glazing materials installed in the side windows of some New York City Transit Authority (NYCTA) buses. As explained be low, the information you provided in your letters and in your phone conversations with Stephen Oesch of my staff and the information provided by NYCTA in a June 19, 1986 letter to the agency indicates the glazing materials installed in the NYCTA buses do not comply with the marking requirements of the standard.

You explained in your letter that the glazing material used in the side and standee windows in the buses is Lexan sheet, which is a plastic material manufactured by General Electric. According to your letter, the Lexan glazing material used in these wind ows can meet all of the performance requirements set in Standard No. 205 for "AS-5" glazing materials. However, the material apparently was not marked as "AS-5" material, but may have instead been marked "AS-4/6." (Information provided to the agency by t he NYCTA in June 1986 indicates that the windows did not contain any "AS" number. At the time of your phone conversation with Mr. Oesch, you had not been able to confirm what markings, if any, had been placed on the glazing material by General Electric).

Standard No. 205 specifies performance and location requirements for glazing used in new vehicles and glazing sold as replacement equipment. (The various types of glazing are designated as "items" in the standard): Plastic glazing materials, such as Lexa n, can be used in a number of different locations in a bus depending on which performance requirements the glazing meets. If the plastic glazing meets the requirements set for AS-5 glazing materials, it can be used in any window in a bus, except for the windshield, windows to the immediate right and left of the driver and the rearmost windows if used for driving visibility.

In addition to setting performance requirements for different items of glazing, the standard requires glazing materials to contain certain markings. The marking requirements of S6 of the standard vary depending on the intended use of the glazing and the person that is marking the glazing. At a minimum, the standard requires the glazing to be marked pith the AS number (which indicates that the material meets the performance requirements set for that "item" of glazing material), a model number and the man ufacturer's logo. The information the agency has received about the markings on the glazing installed in the NYCTA buses indicates that the glazing does not have an AS number marked on it.

Any glazing sold for use in a motor vehicle must conform to the applicable requirements of Standard No. 205. Since there appears to be an apparent noncompliance, General Electric is required by Part 573 of our regulations to file a report with the agency providing additional details about the noncompliance and General Electric's plans to remedy the noncompliance. As you requested of Mr. Oesch, I am also enclosing a copy of the agency's regulation concerning the filing of a petition for a determination t hat a noncompliance is inconsequential.

If you have any further questions, please let me know.

Sincerely,

Erika Z. Jones Chief Counsel Enclosures

August 26, 1986

Office of the Chief Council National Highway Traffic Safety Administration 400 7th Street, S.W. Washington, D.C. 20590

Re: Letter from General Electric Company - August 13, 1986

Gentlemen:

In reference to my letter dated August 13, 1986 concerning the incorrect marking of glazing materials a matter of some urgency has come to my attention. It seems that the New York City Transit Authority is exercising exceptional prudence with regard to t his matter. If this situation continues hundreds of thousands of dollars worth of perfectly good material will be excluded from use.

It would be greatly appreciated if you could respond to the following.

Mr. William Wallace New York City Transit Authority 25 Jamaica Avenue Brooklyn, NY 11207

Mr. R.J. Watters Commercial Plastics & Supply Company Transportation Division 1620 Woodhaven Drive Cornwells Heights, PA 19020

If you have any questions or concerns please feel free to contact me. I can be reached at (413)448-7629. I thank you in advance for you cooperation.

Regards,

Bruce M. Torrey Product Performance Specialist

August 13, 1986

Office of the Chief Council National Highway Traffic Safety Administration 400 7th Street S.W. Washington, D.C. 20590

Re: Incorrect Glazing Marking

Gentlemen:

In order to satisfy the Department of Transportation in New York City I need an official statement concerning the following matter.

Lexan sheet, manufactured by General Electric Company is a plastic (polycarbonate) material typically used for bus side windows and standee glazings. These products are tested per ANSI Z26.1 standards on a regular basis and submitted to AAMVA for verific ation and certification.

During this process our Lexan@ MR-5000 Bronze tinted material was assigned an AS 4/6 designation, as it appears on the Notice of Equipment Compliance from AAMVA. Apparently a misinterpretation of ANSI Z26.1 test NO. 2 which requires minimum light-transmi ssion value of 70%. (1/4" Bronze Lexan@ MR5000 has a value of 53%).

Instead of being appropriately marked, AS-5, they received the AS 4/6 marking.

The following, details pertinent information.

Material Distributor:

Commercial Plastics & Supply Corp. Transportation Division 1620 Woodhaven Drive Cornwells Heights, PA 19020

Bus Manufacturer:

Blitz Bus & Truck 4525 W. 26th Street Chicago, IL 60623

This particular situation involves some 3,000 side windows and another 390 standee windows.

Enclosed you will find supporting test data and a copy of our original Notice of Equipment Compliance.

If you have any questions please feel free to contact me. I can be reached at (413)448-7629.

Regards,

Bruce M. Torrey

Enclosures Omitted.

ID: 7323

Mr. Kevin B. Brown
EG&G Idaho, Inc.
P.O. Box 1625
Idaho Falls, ID 83415-4103

Dear Mr. Brown:

This responds to your letter concerning 49 CFR 567 requirements for intermediate or final stage manufacture vehicle labeling. I apologize for the delay in responding. You stated in your letter that EG&G Idaho, as prime contractor for the Department of Energy, Idaho Field Office, procures and maintains all government-owned vehicles, and occasionally procures truck chassis purchased through the General Services Administration for subsequent mounting of service bodies.

I am pleased to have this opportunity to explain our regulations to you. Before addressing the specific issues raised in the letter, some background information may be helpful. The National Traffic and Motor Vehicle Safety Act of 1966, as amended, 15 U.S.C., 1381-1431 (hereinafter "Safety Act") authorizes this agency to establish Federal motor vehicle safety standards for new motor vehicles and items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment. Rather, the Safety Act establishes a self-certification process which requires each manufacturer, in the exercise of due care, to ensure and certify that its products meet all applicable Federal safety standards. Thereafter, NHTSA periodically tests vehicles and equipment for compliance with the standards and investigates allegations of safety-related defects.

In addition, the Safety Act only requires new vehicles to comply with applicable safety standards. The only provision of the Safety Act that would apply after the first purchase of a vehicle is 15 U.S.C. 1397 (a)(2)(A), which states in relevant part that:

No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle ... in compliance with an applicable Federal motor vehicle safety standard.

The first question to be answered is whether EG&G Idaho is a manufacturer. Under 49 CFR 568.3, a final-stage manufacturer is "a person who performs such manufacturing operations on an incomplete vehicle that it becomes a completed vehicle." An incomplete vehicle is "an assemblage consisting, as a minimum, of frame and chassis structure..." that requires "further manufacturing operations, other than the addition of readily attachable components... ." Readily attachable components include items such as mirrors or tire and rim assemblies. Service bodies are not "readily attachable components." Therefore, in installing service bodies on new chassis, EG&G is acting as a final-stage manufacturer under federal regulations.

49 CFR 586.6 establishes certain requirements for final-stage manufacturers, including:

(a) Each final-stage manufacturer shall complete the vehicle in such a manner that it conforms to the standards in effect on the date of the manufacture of the incomplete vehicle, the date of final completion, or a date between those two dates. ... (b) Each final-stage manufacturer shall affix a label to the completed vehicle in accordance with 567.5 of this chapter.

EG&G must attach the proper label to the completed vehicle as set out in 49 CFR 567.5(c), a copy of which is enclosed for your convenience. According to your letter, EG&G mounts bodies in accordance with the original (i.e., incomplete) manufacturer's instructions or recommendations. In that case, EG&G's certification that the completed vehicle conforms to all applicable safety standards can state simply that the vehicle has been completed in accordance with the prior manufacturer's instructions, per 567.5(c)(7).

When EG&G mounts a new body on a new chassis, the resulting vehicle is subject to the Safety Act and the certification requirements of 49 CFR 567 and 568. However, according to your letter, you also mount bodies on "existing used" chassis. 49 CFR 571.7(e) deals with combining new and used components:

When a new cab is used in the assembly of a truck, the truck will be considered newly manufactured for purposes of paragraph (a) of this section [stating that safety standards apply to all relevant motor vehicles], the application of the requirements of this chapter, and the [Safety] Act, 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.

This means that the vehicle resulting from placing a new body upon a used chassis is a used vehicle. If, in addition to adding a new body, the operation also modifies the chassis by adding new components, such as new engine, transmission, suspension, etc., it is more likely that the resulting vehicle would be considered a new vehicle. If your vehicles produced with "existing used chassis" will incorporate the engine, transmission, and drive axle from the existing used chassis, the completed vehicles would be "used" and would not require vehicle certification. Some of our standards, however, apply to individual items of motor vehicle equipment (e.g., brake hoses and fluids, lighting equipment, tires, seatbelt assemblies, glazing). If your converted vehicles incorporate new items of these types of equipment, the items must comply with the applicable Federal safety standards. For example, lights are subject to requirements specified in Standard No. 108, and glazing is subject to requirements specified in Standard No. 205.

Finally, you ask whether "EG&G Idaho need[s] to be certificated... ." There is no procedure to certify any manufacturer. It is the manufacturer that must certify that its vehicles meet the applicable federal safety standards. However, you should submit the manufacturer's information required by 49 CFR 566 to NHTSA. This information includes the name and address of the manufacturer (in this case, EG&G), a description of the type of vehicle manufactured, the use for which it is intended, and the fact that EG&G is a final stage manufacturer. I have enclosed a copy of Part 566 for your information.

For your information, I have also enclosed a general information sheet for new manufacturers that gives a succinct outline of the relevant NHTSA regulations and explains how to get copies of those regulations.

I hope this information is helpful. If you have any further questions or need some additional information on this subject, feel free to contact David Elias of my staff at this address or by telephone at (202) 366-2992.

Sincerely,

Paul Jackson Rice Chief Counsel Enclosures ref:567 d:9/4/92

ID: nht76-2.31

DATE: 03/05/76

FROM: AUTHOR UNAVAILABLE; S. P. Wood; NHTSA

TO: Department of California Highway Patrol

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of March 10, 1976, asking whether S4.6(b) of Motor Vehicle Safety Standard No. 108 allows a flashing side marker lamp "in any location on the side of a motor vehicle without having to comply with State law pertaining to side-mounted turn signals."

S4.6(b) allows side marker lamps to flash for signalling purposes. Since a flashing side marker lamp is in essence a side turn signal lamp, any State regulation specifically addressed to location and flash rate of side turn signals would appear to be preempted by Standard No. 108, if the side marker lamp is combined with a side turn signal lamp. If the side turn signal lamp is a separate lamp, then it would be subject to State regulation.

Your inquirer wishes to install "a side marker lamp on each side near the middle of the trailer to flash with the turn signal lamps." If the lamp to be added is not the intermediate side marker lamp required by Standard No. 108 for trailers whose length is 30 feet or more, it would be governed by the California Vehicle Code and not preempted.

We intend to address the issues of side mounted turn signal lamps, flashing side marker lamps, and flashing headlamps in a rulemaking proposal whose publication is imminent, and I will include your letter in the Docket as a comment to be considered.

YOURS TRULY,

DEPARTMENT OF CALIFORNIA HIGHWAY PATROL

March 10, 1976

File No.: 61.A218.A4343

James C. Schultz Chief Counsel National Highway Traffic Safety Administration

We have a question concerning an interpretation of Section S4.6(b) of FMVSS No. 108. This paragraph states that "means may be provided to flash headlamps and sidemarker lamps for signaling purposes".

We have had an inquiry from a supplier to a major trailer manufacturer as to whether or not he can install a sidemarker lamp on each side near the middle of the trailer to flash with the turn signal lamps. The California Vehicle Code provides that "side-mounted turn signal lamps of an approved type projecting a flashing amber light to either side may be used to supplement the front and rear turn signals. Side-mounted turn signal lamps mounted to the rear of the center of the vehicle may project a flashing red light no part of which shall be visible from the front." The Administrative Regulations require the approved side turn signal lamps to meet the same requirements as SAE Standard J914a.

These standards were adopted to assure that lamps installed on a vehicle as a side turn signal lamp had sufficient performance to be of value to other motorists both day and night, whether mounted on a passenger car, a truck or a trailer. A range of mounting heights was established in our regulations so that the side turn signal lamp would be near the eye height of drivers alongside the vehicle.

In the past, the only vehicles flashing the sidemarker lights as allowed by your standard were passenger cars. In these cases, we had read your standard as permitting the minimum number of sidemarker lamps required by your standard to flash but not giving authority for the indiscriminate addition of numerous other sidemarker lamps in other locations on the side of the vehicle.

We do not see any particular problem with allowing a required sidemarker lamp to flash simultaneously with a required turn signal lamp on the same side and on the same end of the vehicle. Unfortunately, one major passenger car manufacturer selected a system that caused the sidemarker lamps to flash alternately with the turn signals which, in our opinion, detracts from the signal value of the required turn signal instead of adding to it, particularily when both signals are seen to flash alternately at certain angles from the front or rear of the vehicle.

We now come to the question. Does Section S4.6(b) permit a manufacturer to install and flash with the turn signal any sidemarker lamp in any location on the side of a motor vehicle or trailer without having to comply with State law pertaining to side-mounted turn signals?

If the answer is "yes", we ask that you consider an appropriate revision to FMVSS No. 108 within the near future. We suggest that an amendment be proposed to require the side turn signals to flash simultaneously and in unison with the appropriate turn signal rather than alternately with the signal. In addition, we request that:

1. Only the minimum required sidemarker lamps on the each end of the vehicle be allowed to flash with the turn signal lamps.

2. Only sidemarker lamps near the eye height of passenger car drivers alongside the vehicle be allowed to flash. Sidemarker lamps at the extreme tops of trucks and trailer lamps are so far removed from the turn signal that another driver seeing them blink would likely be distracted by them instead of relating them to a turn being signaled.

3. New provisions be worded so attempts of various state laws to require higher-performing side mounted turn signals that are effective in the daytime are not placed in limbo because the Federal Standard allows a far less effective lamp of only 0.25 to 0.62 candlepower to flash in its place.

4. High mounted sidemarker lamps on buses not be allowed to flash as part of the turn signal system, because transit buses are permitted in this State to simultaneously flash all clearance and sidemarker lamps as a crime warning signal when driver or passengers are accosted. These signals are visible both from police patrol cars and police helicopters. Before-and-after surveys have shown that they are quite effective in making substantial increases in the rate of apprehension of suspects.

5. Headlamps not be allowed to flash with the turn signal lamps as now permitted. It is more important that a driver of a vehicle be able to see a lighted roadway in the direction in which he is going rather than using the headlamps to supplement an already effective front turn signal.

We would appreciate receiving your interpretation of the flashing headlamp and sidemarker lamp provisions. If you wish, we will be pleased to send you copies of our regulations on side turn signal lamps, alternately flashing headlamps for emergency vehicles, and data on the reduction in crime on buses following the installation of flashing crime warning lamps.

WARREN M. HEATH Commander Engineering Section

ID: nht93-4.48

DATE: June 25, 1993

FROM: Kenneth P. Simons -- Lawyer

TO: Department of Transportation -- Trucking Division

TITLE: None

ATTACHMT: Attached to letter dated 4/25/94 from John Womack to Ken Simons (A42; Std. 121)

TEXT:

I would like an answer or information as to whether or not over the road trailers (as in tractor trailer) of recent manufacture are required to be equipped with "maxi" brakes on one or both axles.

The "maxi" brake I am referring to is found on all road tractors and sets the brakes automatically when the air pressure gets down to a minimum level.

Thank you for you anticipated cooperation.

ID: nht71-5.24

DATE: 12/15/71

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

TO: Mobilefreeze Co., Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of September 7, 1971, to Mr. Stan Haransky, Truck Body and Equipment Association, Inc., concerning the mounting height of lamps and reflectors on your motor-cycle trailers.

A copy of Federal Motor Vehicle Safety Standard No. 108, "Lamps, Reflective Devices and Associated Equipment" is enclosed for your information. The minimum mounting height for lamps and reflectors listed in Table IV of this Standard is 15 inches. We do not have the authority to exempt any motor vehicles from meeting these requirements.

Enc.

ID: nht74-1.28

DATE: 07/15/74

FROM: C. BAKER FOR E. T. DRIVER -- NHTSA

TO: Stanley Electric Co., Ltd.

COPYEE: L. C. OWEN

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of June 27 concerning the location of motorcycle turn signal lamps relative to a combination stop lamp and reflex reflector.

The minimum edge to edge separation distance specified in Table IV of FMVSS No. 108 for motorcycle turn signal lamps is to be measured from the edge of the illuminated surface of both lamps.

The answer to your question 2 is therefore applicable, "2. edge to edge of tail and stop lamp so drawn in sketch C?"

ID: 77-3.46

TYPE: INTERPRETATION-NHTSA

DATE: 08/04/77

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

TO: Humanoid Systems

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your June 3, 1977, request for confirmation that @ 572.7(b) of Part 572, Anthropomorphic Test Dummy (49 CFR 572), specifies a minimum time period during which the pendulum used in testing may not reverse direction rather than an exact time.

Your interpretation is correct. The specification that the pendulum "shall not reverse direction until T=123 ms" means that reverse travel must not occur earlier than 123 milliseconds after chordal displacement begins. The agency believes that this language can be improved and intends to clarify it at the next opportunity.

ID: nht94-9.3

TYPE: Interpretation-NHTSA

DATE: January 11, 1994

FROM: Don Vierimaa -- Truck Trailer Manufacturers Association

TO: Pat Boyd -- NHTSA

TITLE: None

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

TEXT:

A customer has requested that a 4 inch (100 mm) wide retroreflective sheeting be placed along the side of a trailer he is ordering. The manufacturer is reluctant to provide this width of sheeting since the rule states in S5.7.1.3(d) that Grade DOT-C2 sheeting shall have a width of 50 mm. This provides no tolerance nor does it provide a minimum.

May a manufacturer install 4 inch (100 mm) wide retroreflective sheeting instead of 2 inch (50 mm) sheeting on the side of new trailers?

ID: nht94-1.18

TYPE: Interpretation-NHTSA

DATE: January 11, 1994

FROM: Don Vierimaa -- Truck Trailer Manufacturers Association

TO: Pat Boyd -- NHTSA

TITLE: None

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

TEXT:

A customer has requested that a 4 inch (100 mm) wide retroreflective sheeting be placed along the side of a trailer he is ordering. The manufacturer is reluctant to provide this width of sheeting since the rule states in S5.7.1.3(d) that Grade DOT-C2 sh eeting shall have a width of 50 mm. This provides no tolerance nor does it provide a minimum.

May a manufacturer install 4 inch (100 mm) wide retroreflective sheeting instead of 2 inch (50 mm) sheeting on the side of new trailers?