ID: nht76-5.50

DATE: 07/01/76

FROM: AUTHOR UNAVAILABLE; John Womack for F. Berndt; NHTSA

TO: ROHR Industries, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Rohr Industries' April 27, 1976, letter asking how to test an emergency exit that contains no glazing in conformity with the provision of Standard No. 217, Bus Window Retention and Release, that specifies testing before and after a window retention test (S5.3.2.). You also ask whether the emergency exit identification requirements of S5.5.1 specify the placement of operating instructions at a designated seating position which does not qualify as an "adjacent seat" under the definition found in S4 of the standard.

The window retention requirement is not required in the case of an emergency exit that contains no glazing. Because this requirement is clearly inapplicable to such an exit, the emergency exit release requirements of S5.3.2 must be met, but without the need to conduct a window retention test.

In answer to your second question, S5.5.1 requires that a label indicating the location of the nearest exit release mechanism be placed at "adjacent seats" to any exit whose release mechanism is not located within the occupant space of that adjacent seat. There are no labeling requirements in S5.5.1 for seating that is not "adjacent" to the exit. As you note, some interior configurations result in seating whose "occupant space" is not within 10 inches of any emergency exit (measured as set forth in S4). Such seating would not have to be labeled with the location of the nearest release mechanism, although some manufacturers do provide this information voluntarily. The agency has evaluated a requirement for this labeling but considers present labelling practices adequate at this time.

SINCERELY,

April 27, 1976

Robert Williams Office of Crashworthiness National Highway Traffic Safety Administration U.S. Department of Transportation

Reference: FMVSS No. 217, Bus Window Retention and Release

This letter is forwarded in response to your suggestion made during our telephone conversation of April 15, 1976, during which we discussed the interpretation of certain requirements contained in the referenced FMVSS. Our discussion concerned an emergency roof exit installed in an urban transit bus in accordance with paragraph S5.2.1, since the bus configuration precludes installation of an accessible rear emergency exit.

The roof exit under discussion is not a push-out window. No window glazing is involved. It is of a metal-foam-sandwich construction comparable to the surrounding roof. Paragraph S5.3.2 requires each emergency exit allow manual release of the exit "both before and after the window retention test required by S5.1". Clarification of the application of these window retention tests to the non-glazed roof hatch is requested.

a. Is it required that a non-glazed roof emergency exit be subjected to the window retention test specified by paragraphs S5.1?

b. If testing is required, which of the terminating events in S5.1 are applicable when testing a non-window type exit?

c. If testing is required, must the test be accomplished with the vehicle resting on it's side per Figure 3B, Roof Emergency Exit?

During our phone conversation referenced above, you expressed your unofficial interpretations as being that a non-glazed roof emergency exit would be subject to the release force requirements of the standard but not the retention force requirements or testing under S5.1.

Clarification with respect to emergency exit identification is also requested. Paragraph S5.1 states in part -

". . .When a release mechanism is not located within the occupant space of an adjacent seat, a label meeting the requirements of S5.5.2 that indicates the location of the nearest release mechanism shall be placed within that occupant space."

Paragraph S4 defines an "adjacent seat" and "occupant space" in a manner which indicates that a designated seating position is not to be identified as an "adjacent seat" unless some portion of it's occupant space is not more than ten inches from an emergency exit, for a distance of at least fifteen inches measured horizontally and parallel to the exit. As you know, certain bus seating configurations are such that some designated seating positions are directly adjoining fixed windows/piar panels (non-glazed areas between windows). These fixed (non-push-out) windows and pier panels are not designed as, nor marked as emergency exits. The occupant space of the adjoining designated seating position is not within ten inches of an emergency exit for a distance of at least fifteen inches measured horizontally and parallel to that exit. Therefore, it is our understanding that these seating positions are not, by definition, adjacent seats.

a. Do these non-adjacent seats adjoining a fixed window or a pier panel require emergency exit location referral labelling under the current edition of FMVSS No. 217?

b. If so, which paragraph specifies such a requirement?

c. If not, has such a requirement been considered?

Here also during our phone conversation previously referenced, you expressed an unofficial opinion that these particular seating positions were not covered by labelling requirements. Please confirm.

Your review of and assistance with above will be greatly appreciated.

R. L. Ratz Safety Engineering Specialist

ID: nht72-1.46

DATE: 06/12/72

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: The Peterson Company

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of May 24, 1972, inquiring whether Standard No. 213 requires head rests, arm rests, and shields of certain Peterson child seats to be covered with nonrecovery, or slow-recovery energy absorbing material.

Paragraph S4.10.3 of Standard No. 213 exempts the contactable area of a rigid side of a child seating system from the requirement that it be covered with deformable, nonrecovery, or slow-recovery energy absorbing material (S4.10.1 and S4.10.2), when the contactable area of the side that is higher than the system's seating surface is at least 24 square inches. We would consider head rests, arm rests, and shields of the Peterson child seats in question to be within the exemption of S4.10.3 if their contactable area above the child seating surface is 24 square inches or more.

I point out, however, that the proposal of September 23, 1970 (35 F.R. 14786) would alter this result, as the exemption would no longer extend to any components contactable by the head.

ID: 2790y

Mr. Danny Pugh
Engineering Manager
Utilimaster Corporation
65266 State Rd. 19
P.O. Box 585
Wakarusa, IN 46573

Dear Mr. Pugh:

This responds to your letter seeking an interpretation of Standard No. 208, Occupant Crash Protection (49 CFR 571.208). More specifically, you asked about the requirements for safety belts at the various seating positions in vehicles with a gross vehicle weight rating under 10,000 pounds that you called "van conversions."

You first asked whether a "van conversion" would be classified as a passenger car, truck, or multipurpose passenger vehicle. Vehicles commonly called "vans" may be classed in four different vehicle categories (set forth at 49 CFR 571.3) for the purposes of our safety standards, depending on the configuration of the particular "van." Most cargo vans are classified as "trucks" under our safety standards, because those vehicles are "designed primarily for the transportation of property or special purpose equipment." Most passenger vans are classified as "multipurpose passenger vehicles," because they do not meet the definition of a "truck", but are "constructed on a truck chassis." Those vans that have eleven or more designated seating positions are classified as "buses," because they are "designed for carrying more than 10 persons. Finally, one minivan (the Nissan Axxess) was certified by its manufacturer as a "passenger car," because it was "designed for carrying 10 persons or less."

Additionally, the National Traffic and Motor Vehicle Safety Act places the responsibility for classifying a particular vehicle in the first instance on the vehicle's manufacturer. For this reason, NHTSA does not approve or endorse any vehicle classification before the manufacturer itself has classified a particular vehicle. NHTSA may reexamine the manufacturer's classification in the course of any enforcement actions. If you are interested in the appropriate classification for a particular van conversion, we will offer our tentative opinion if you will provide us with detailed information on the van conversion in which you are interested.

You next asked on what date safety belts were required in "van conversions," what type of safety belts, and at what locations those belts were required. As explained above, we do not class vehicles as "van conversions" for the purposes of our safety standards. If the vans were classed as passenger cars, passenger cars manufactured on or after January 1, 1968 were required to have lap/shoulder safety belts at the front outboard seating positions and either lap/shoulder or lap-only safety belts at every other seating position in the car. Beginning December 11, 1989, passenger cars were required to have lap/shoulder safety belts at both front and rear outboard seating positions, with either lap/shoulder or lap-only safety belts at every other seating position. Since September l, l989, all passenger cars are required to be equipped with automatic crash protection for outboard front-seat occupants.

Multipurpose passenger vehicles and trucks with a gross vehicle weight rating of 10,000 pounds or less manufactured on or after July 1, 1971 were required to have lap/shoulder safety belts at the front outboard seating positions and either lap/shoulder or lap-only safety belts at every other seating position in the vehicle. Beginning September 1, 1991, vans classified as multipurpose passenger vehicles or trucks (other than motor homes) must have lap/shoulder belts at both front and rear outboard seating positions, with either lap or lap/shoulder belts at all other seating positions. Motor homes manufactured on or after September 1, 1991 will continue to be required to have lap/shoulder belts at front outboard seating positions and either lap/shoulder or lap-only safety belts at every other seating position. In addition, effective September l, l99l vans must meet dynamic crash test injury criteria for the front outboard seating positions.

If the vans were classed as buses, buses manufactured on or after July 1, 1971 were required to be equipped with either a lap/shoulder or a lap-only safety belt at the driver's seating position. Beginning September 1, 1991, buses with a gross vehicle weight rating of 10,000 pounds or less (except school buses) must be equipped with lap/shoulder belts at all front and rear outboard seating positions and either lap/shoulder or lap-only safety belts at every other seating position.

Also, the agency has proposed extending the automatic crash protection requirements mentioned above to these other vehicle classifications.

I hope this information is useful. If you have any further questions or need some additional information on this subject, please contact Steve Kratzke of my staff at this address or by telephone at (202) 366-2992.

Sincerely,

Paul Jackson Rice Chief Counsel

ref:208#571 d:12/13/90

ID: 571.108--Supplement beam--Boykin--16-0884

Mr. Marcus Boykin

B-G Innovative Safety Systems, LLC

79 Pasture Road

Lexington, TN 38351

Dear Mr. Boykin:

This responds to your letter asking about the application of Federal Motor Vehicle Safety Standard (FMVSS) No. 108, “Lamps, reflective devices, and associated equipment,” to a lighting system your company has developed.  In your letter and phone conversation with John Piazza of my staff, you describe your product as “an auxiliary vehicle lamp operating system” for use both as original equipment (OE) and as aftermarket equipment.

You state that your product, which adapts to the existing headlight wiring harness, provides a supplemental lower beam from the existing upper beam when the lower beam fails.  We understand that, when the lower beam is not in a failed state, the headlight system, controls, and telltales function normally.  If the lower beam is selected and has failed or does fail, your system provides a supplemental lower beam from the existing upper beam.  You state that the lighting on the converted upper beam is “diffused down to the same output illumination as” the lower beam.  If the upper beam is selected, the upper beam will continue to function normally. 

We further understand that, with respect to the OE version of your product, you contemplate a dashboard warning to warn the driver that the normal lower beam is not functioning.  In the aftermarket version of your product, once the vehicle’s lower beam has failed and your device is providing a supplemental lower beam, every time the engine is started the headlights will flash three times to warn the driver that the original equipment lower beam is not operating and that your device is providing a supplemental lower beam.  You state that you are seeking “interpretation and approval” of your device.

As we explain below, while NHTSA does not provide approvals of motor vehicles or motor vehicle equipment and does not make compliance determinations outside of an agency compliance proceeding, we are able to provide you with our interpretation of how NHTSA’s statute and regulations would apply to your product as you have described it to us.  We believe that your product would be considered supplemental lighting.  As such, it may be installed as original equipment as long as it does not impair the effectiveness of any required lighting.  If your product is offered as aftermarket equipment, it would not be directly subject to FMVSS No. 108 but would be subject to the Safety Act’s make inoperative prohibition.

Background

The National Highway Traffic Safety Administration (NHTSA) is authorized by the National Traffic and Motor Vehicle Safety Act (Safety Act), 49 U.S.C. Chapter 301, to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and new items of motor vehicle equipment.  NHTSA does not provide approvals of motor vehicles or motor vehicle equipment and does not make determinations as to whether a product conforms to the relevant FMVSS outside of an agency compliance proceeding.  Instead, the Safety Act requires manufacturers to self-certify that their products conform to all applicable FMVSSs.  Manufacturers must also ensure that their products are free of safety-related defects.

This letter provides you with our interpretation of how the statute and regulations administered by NHTSA would apply to your product as you have described it to us, based on our understanding of the information provided.  This is not an “approval” of your product.

Vehicle lighting sold as OE is regulated under FMVSS No. 108.  (All references in this letter are to subsections of FMVSS No. 108 unless otherwise noted.).  FMVSS No. 108 requires vehicles to be equipped with certain types of lamps (known as “required” lamps), which must meet very specific and detailed performance standards.[1]  All other lamps are considered “supplemental” lamps.[2]  Unlike OE required lamps, OE supplemental lamps are not required to meet any specific performance requirements.  However, they are required to comply with certain generally-applicable provisions of FMVSS No. 108.  One of these provisions is set forth in S6.2.1, which states: “No additional lamp, reflective device, or other motor vehicle equipment is permitted to be installed that impairs the effectiveness of lighting equipment required by this standard.”

Both OE and aftermarket vehicle lighting are subject to the Safety Act’s “make inoperative” prohibition (49 U.S.C. § 30122), which prohibits a manufacturer, distributor, dealer, rental company, or motor vehicle repair business from knowingly making inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable FMVSS.  While this “make inoperative” prohibition does not apply to individual vehicle owners, NHTSA encourages vehicle owners not to remove or otherwise tamper with vehicle safety equipment.  Also, any modifications made by a vehicle owner would have to comply with applicable state law. 

Discussion

FMVSS No. 108 requires vehicles to be equipped with one of several permissible headlighting systems.  Headlighting systems are comprised of headlamps and associated hardware.  The purpose of headlighting is primarily to provide forward illumination.[3] 

The threshold issue presented by your request is whether your product is part of the required headlighting system, and thus subject to FMVSS No. 108’s requirements applicable to headlighting systems or, instead, supplemental lighting that is regulated by FMVSS No. 108’s impairment provision.   

In determining whether lighting equipment that provides forward illumination is part of the required headlighting system or, instead, supplemental lighting, NHTSA looks at several factors.  These include: (1) where the lamp directs its light; (2) whether it uses a headlamp replaceable light source to emit a beam that provides significantly more light flux than supplemental cornering lamps or fog lamps; (3) whether the lamp is intended to be used regularly, or is limited to more narrow driving conditions and situations; (4) whether the vehicle’s complete lighting system, not including the lamp in question, would include all of the forward lighting equipment required by FMVSS No. 108;  (5) whether there is a manual on/off switch; and (6) whether the lighting feature is one that activates only upon the failure of an element of the required headlighting system and acts as a temporary backup of that lighting element.[4] 

The last of these factors is most relevant to your product.  Prior agency interpretations have found that a lighting feature that activates an upper beam light source when the lower beam fails or a lower beam headlamp upon the failure of an upper beam headlamp is supplemental lighting.[5]  The system you describe activates a back-up beam only upon the failure of the required lower beam.  Accordingly, we believe it is supplemental lighting. 

Since you contemplate selling your supplemental lighting device as original and/or aftermarket equipment, we will consider the requirements affecting each of these.

Supplemental lighting installed as original equipment

Supplemental lighting installed as OE (i.e. before sale to first purchaser other than for resale) is permitted if the lighting does not impair the effectiveness of any lighting equipment required by FMVSS No. 108 (S6.2.1).  If you are the manufacturer of original lighting equipment required by FMVSS No. 108, but not the manufacturer of the vehicle on which it is installed, the vehicle manufacturer, and not you, has the legal responsibility under the Safety Act to certify that the vehicle complies with FMVSS No. 108 and all other applicable FMVSSs.  Accordingly, the vehicle manufacturer must certify that supplemental lighting installed as OE complies with S6.2.1.  Effectiveness may be impaired if, among other things, the device creates confusion with the signal sent by another lamp, or functionally interferes with it, or modifies its candlepower to either below the minima or above the maxima permitted by the standard.[6] 

Table XIX has specific photometry requirements (maxima and minima) for lower beams.  Activation of an upper beam light source when a lower beam source fails raises considerations of glare.  The lower beam maxima are meant to ensure that other roadway users are not glared.  If your device produces a supplemental beam that exceeds the lower beam photometric maxima, we would consider that to impair the effectiveness of the headlighting system.  Accordingly, your device needs to modify the upper beam to ensure that the lower beam photometric maxima are not exceeded. [7]  Because your device is supplemental lighting, it would not be required to provide sufficient illumination to meet or exceed the photometric minima required for a lower beam headlamp.  However, we note that by reducing the output illumination of the upper beam to that of the lower beam, the reduced upper beam would provide only a limited amount of illumination that may not be sufficient to usefully illuminate the road. 

For your information, we also point out below several other requirements of which you should be aware in designing and manufacturing your product.  (Note that it is the responsibility of manufacturers, and not NHTSA, to identity all FMVSSs applicable to their products and certify the compliance of their products with the standards.)

• Your product must not interfere with the activation and operation of the upper beam.    
•  It may not impair the effectiveness of the upper beam headlamp indicator required by S9.5.  When your device is providing a supplemental lower beam, it should do so in a way that the upper beam indicator is not activated.  Also, when the driver (or vehicle, if it has a semiautomatic headlamp beam switching device, or automatic headlights) has activated the upper beams, the upper beams must be activated and the upper beam indicator must be activated.  
• S9.4 requires that “the lower and upper beams must not be energized simultaneously except momentarily for temporary signaling purposes or during switching between beams.” 
• The headlamps must be steady burning, except that they may be flashed for signaling purposes.[8]  We would not consider your system’s momentary flashing function as violating this requirement because it is similar to a signaling function and would not be likely to confuse other motorists because it only flashes upon start-up.  
• The device generally should not function in such a way that it would be likely to confuse other motorists (for example, it should not mask the ability of other drivers to perceive the front turn signal).
• If a telltale or control is offered as original equipment, it must comply with any relevant requirements in FMVSS No. 101, “Controls and displays.”

We wish to point out that Table I-a requires that “[t]he wiring harness or connector assembly of each headlighting system must be designed so that only those light sources intended for meeting lower beam photometrics are energized when the beam selector switch is in the lower beam position[.]”  Although it may appear that a device such as yours might not meet this requirement, NHTSA has interpreted the requirement otherwise. 

This issue arises if the lower beam is activated (with the beam selector switch in the lower beam position) and then fails, after which a system (such as yours) activates a modified upper beam as a backup lower beam.  If the backup lower beam utilizes upper beam light sources that are not normally used for meeting lower beam photometrics, the backup lower beam might be viewed as violating this requirement.[9]  However, prior interpretations have concluded that this Table I-a requirement does not apply to a failure condition in which a supplemental beam supplements a failed lower or upper beam, assuming the supplemental light does not otherwise impair the effectiveness of any required lighting.[10]  Applying that line of reasoning, we believe that your system would not create a noncompliance with the Table I-a requirement.

Supplemental lighting offered and installed as aftermarket equipment

Supplemental lighting offered as aftermarket equipment (accessory lighting) is not directly subject to FMVSS No. 108, which applies only to original equipment and lighting equipment manufactured to replace original lighting equipment required by FMVSS No. 108.  Section 30122 of the Safety Act, however, prohibits a manufacturer, distributor, dealer, rental company, or motor vehicle repair business from knowingly making inoperative, in whole or in part original required lighting equipment.  In applying the make inoperative prohibition to accessory lighting we typically ask whether the accessory lighting would impair the effectiveness of any required lighting.  Generally, if an item of accessory lighting would not be permitted as original equipment, commercial entities will not be permitted to install the lighting as an aftermarket accessory for a vehicle in use.  Thus, the make inoperative analysis is generally the same as the impairment analysis we applied above in the context of supplemental lighting installed as original equipment.  We observe that, due to varying headlamp designs throughout the vehicle fleet, there may be potential compatibility issues with the product you describe and certain vehicles.  In addition, manufacturers of aftermarket lighting accessories are subject to the Safety Act’s defect notification and remedy requirements discussed above.    

We also note that manufacturers of equipment to which an FMVSS applies must meet the manufacturer identification requirements set out in 49 CFR Part 566.  For these and other requirements, you may consult NHTSA’s New Manufacturers Handbook, available at https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/manufacturer_information_march2014.pdf.

If you have any further questions, please contact John Piazza at (202) 366-2992.

Sincerely,

Jonathan Morrison

Chief Counsel

Dated: 5/17/19

Ref: FMVSS No. 108

[1] The standard’s performance requirements also apply to lamps that are “for replacement of like equipment on vehicles to which this standard applies.”  On a related matter, we note that you state that “drivers with a failed light are out of compliance.”  This is incorrect, as FMVSS No. 108 does not regulate lighting in use.  Therefore, if a headlamp fails in operation, the vehicle is not “out of compliance” with the Federal standard (state laws may apply to in-use performance).

[2] NHTSA also uses the term “auxiliary” lamps.

[3] S4 (“Headlamp means a lighting device providing an upper and/or a lower beam used for providing illumination forward of the vehicle.”) (Formatting in original.)

[4] Letter to [Redacted] (Jan. 21, 2004) ((1)-(5)), available at https://isearch.nhtsa.gov/files/swivelinglamp.3.html (last accessed June 20, 2018); letter to L. W. Camp, Ford Motor Company (July 15, 1998) ((6)), available at https://isearch.nhtsa.gov/files/18080.ztv.html (last accessed June 20, 2018). 

[5] Letter to L. W. Camp, supra (lower beam backing up upper beam); letter to Ian Goldstein, Safe Passage Technologies (July 21, 1998) (upper beam backing up lower beam), available at https://isearch.nhtsa.gov/files/18164.ztv.html.

[6] See, e.g., letter to Byung M. Soh, Target Marketing Systems, Inc. (Sept. 13, 1988), available at https://isearch.nhtsa.gov/gm/88/nht88-3.100.html (last accessed June 20, 2018).

[7] Letter to Ian Goldstein, supra (“Because headlamps are primarily operated on the lower beam, activation of an upper beam light source when a lower beam source fails raises considerations of glare . . . the upper beam in this instance ideally should be activated at a markedly reduced intensity such that it does not impair the effectiveness of required lighting devices [S6.2.1], or, more specifically, that, as a lower beam substitute[] it does not compromise turn signal visibility.”)

[8] Table I-a.

[9] Whether this would occur depends on the design of that particular headlighting system.  For example, this would not be the case if the headlighting system used the same light sources for both the lower and the upper beams.

[10] Letter to L. W. Camp, supra (lower beam supplementing failed upper beam).  See also letter to Ian Goldstein, supra (modified upper beam supplementing failed lower

ID: nht95-4.85

TYPE: INTERPRETATION-NHTSA

DATE: November 27, 1995

FROM: Erika Z. Jones -- Mayer, Brown and Platt

TO: Samuel Dubbin, Esq. -- Chief Counsel, NHTSA

TITLE: FMVSS 207/Request for Interpretation

ATTACHMT: 1/4/96 letter from Samuel J. Dubbin to Erika Z. Jones (A44; Redbook 2; Std. 207)

TEXT: I am writing to request an interpretation of FMVSS 207 S4.4, pertaining to labelling of certain motor vehicle seats.

S4.4 provides that:

"Seats not designated for occupancy while the vehicle is in motion shall be conspicuously labeled to that effect."

It is my understanding that S4.4 does not require designated seating positions to be labeled, even if those seating positions are equipped with a folding seat back that enables that seat to be converted to a bed.

This conclusion is consistent with a letter from your office to Mr. Richard Moss, dated June 30, 1971, in which the Acting Chief Counsel advised that FMVSS 207 does not require designated seating positions to be labeled.

The vehicle seat at issue in my question is generally intended for occupancy while the vehicle is in motion, while it is configured as a bench seat. The bench seat contains several "designated seating positions" equipped with safety belts, and the se at is otherwise certified to FMVSS 207 requirements in the seat configuration. When the seat is converted to a bed by folding down the seat back, however, it is no longer "an occupant seat," as that term is defined in FMVSS 207.

Under these circumstances, it is my understanding that the labeling requirement in S4.4 does not apply, and I respectfully seek your concurrence in this conclusion.

Please let me know if I can obtain any additional information for you. I look forward to your response.

ID: nht90-4.81

TYPE: Interpretation-NHTSA

DATE: December 13, 1990

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Danny Pugh -- Engineering Manager, Utilimaster Corporation

TITLE: None

ATTACHMT: Attached to letter dated 9-13-90 to Chief Counsel, NHTSA from Danny Pugh (OCC 5214)

TEXT:

This responds to your letter seeking an interpretation of Standard No. 208, Occupant Crash Protection (49 CFR S571.208). More specifically, you asked about the requirements for safety belts at the various seating positions in vehicles with a gross vehic le weight rating under 10,000 pounds that you called "van conversions."

You first asked whether a "van conversion" would be classified as a passenger car, truck, or multipurpose passenger vehicle. Vehicles commonly called "vans" may be classed in four different vehicle categories (set forth at 49 CFR S571.3) for the purpose s of our safety standards, depending on the configuration of the particular "van." Most cargo vans are classified as "trucks" under our safety standards, because those vehicles are "designed primarily for the transportation of property or special purpos e equipment." Most passenger vans are classified as "multipurpose passenger vehicles," because they do not meet the definition of a "truck" but are constructed on a truck chassis." Those vans that have eleven or more designated seating positions are cl assified as "buses" because they are "designed for carrying more than 10 persons. Finally, one minivan (the Nissan Axxess) was certified by its manufacturer as a "passenger car" because it was "designed for carrying 10 persons or less."

Additionally, the National Traffic and Motor Vehicle Safety Act places the responsibility for classifying a particular vehicle in the first instance on the vehicle's manufacturer. For this reason, NHTSA does not approve or endorse any vehicle classifica tion before the manufacturer itself has classified a particular vehicle. NHTSA may reexamine the manufacturer's classification in the course of any enforcement actions. If you are interested in the appropriate classification for a particular van conver sion, we will offer our tentative opinion if you will provide us with detailed information on the van conversion in which you are interested.

You next asked on what date safety belts were required in "van conversions," what type of safety belts, and at what locations those belts were required. As explained above, we do not class vehicles as "van conversions" for the purposes of our safety sta ndards. If the vans were classed as passenger cars, passenger cars manufactured on or after January 1, 1968 were required to have lap/shoulder safety belts at the front outboard seating positions and either lap/shoulder or lap-only safety belts at every other seating position in the car. Beginning December 11, 1989, passenger cars were required to have lap/shoulder safety belts at both front and rear outboard seating positions, with either lap/shoulder or lap-only safety belts at every other seating p osition. Since September

1, 1989, all passenger cars are required to be equipped with automatic crash protection for outboard front-seat occupants.

Multipurpose passenger vehicles and trucks with a gross vehicle weight rating of 10,000 pounds or less manufactured on or after July 1, 1971 were required to have lap/shoulder safety belts at the front outboard seating positions and either lap/shoulder o r lap-only safety belts at every other seating position in the vehicle. Beginning September 1, 1991, vans classified as multipurpose passenger vehicles or trucks (other than motor homes) must have lap/shoulder belts at both front and rear outboard seati ng positions, with either lap or lap/shoulder belts at all other seating positions. Motor homes manufactured on or after September 1, 1991 will continue to be required to have lap/shoulder belts at front outboard seating positions and either lap/shoulde r or lap-only safety belts at every other seating position. In addition, effective September 1, 1991 vans must meet dynamic crash test injury criteria for the front outboard seating positions.

If the vans were classed as buses, buses manufactured on or after July 1, 1971 were required to be equipped with either a lap/shoulder or a lap-only safety belt at the driver's seating position. Beginning September 1, 1991, buses with a gross vehicle we ight rating of 10,000 pounds or less (except school buses) must be equipped, with lap/shoulder belts at all front and rear outboard seating positions, and either lap/shoulder or lap-only safety belts at every other seating position.

Also, the agency has proposed extending the automatic crash protection requirements mentioned above to these other vehicle classifications.

I hope this information is useful. If you have any further questions or need some additional information on this subject, please contact Steve Kratzke of my staff at this address or by telephone at (202) 366-2992.

ID: aiam4336

Dear Mr.: Thank your for your letter requesting an interpretation of how Standar No. 205, *Glazing Materials*, would apply to your proposed 'head-up display.' You described your head-up display as a system consisting of components located in the instrument panel and windshield that are capable of optically projecting instrument readings so that they appear forward of the lower part of the windshield. You stated that having the readings projected in this manner places them closer to the driver's line of sight and thus allows the driver to view the information more readily and clearly than if the driver had to look for the information on the instrument panel. As discussed below, the agency has conclude that the standard does not prohibit the use of your proposed display.; Before discussing the substantive question you asked, I want to addres your request that the agency not publicly release two types of information contained in your letter. First, you requested the agency to provide confidential treatment to the detailed description of the technology used in your head-up display. Second, you requested that the agency not disclose the name of your company. You explained in your letter requesting confidential treatment that while the device has been installed on a car displayed at a public automobile show, the technical details of the device are not a matter of public knowledge. You subsequently provided the agency with a copy of your letter in which the proprietary technical details have been deleted. Because the technical details of your proprietary device have not been publicly disclosed, we will treat the technical details as confidential. In addition, we will not disclose the name of your company. However, since all for the agency's interpretations are a matter of pubic record, we will place a copy of your letter, which has been purged of the confidential information and your company name, and our response in the agency's public interpretation file.; In the copy of your letter that has been purged of confidentia information, you explain that your head-up display uses a small membrane that is attached to the windshield to reflect certain information from the instrument panel. You explained that the area of the windshield on which the membrane is attached can meet all of the applicable requirements of Standard No. 205 set for glazing materials used in a windshield, except the requirement that the light transmittance through the glazing material be at least 70 percent. You further explained that the membrane is not opaque, but does have a light transmittance that is less than 70 percent.; Based on your analysis of the requirements of Standard No. 205 and th requirements of the American National Standard 'Safety Code for Safety Glazing Materials for Glazing Motor Vehicles Operating on Land Highways,' (ANS Z26) incorporated by reference in Standard No. 205, you stated that the 70 percent transmittance requirement does not apply to all window areas. You noted that ANS Z26, a manufacturer can place a shade band on the upper edge of a windshield that has a light transmittance of less than 70 percent. You further noted that Standard No. 205 and ANS Z26 do not define the boundaries of the shadeband or set a minimum light transmittance level for the glazing materials used in the shadeband. Futhermore, you pointed out that Standard No. 205 and ANS Z26 do not specifically define what areas of the glazing are requisite for driving visibility.; In support of your position that the area of the windshield affected b your head-up display is not requisite for driving visibility, you noted that the membrane used in the display system covers a small area of the glazing that is located toward the lower left edge of the windshield. To demonstrate that the membrane is not within an area requisite for driving visibility, you examined the effect of the membrane's location on the ability of the car to comply with the requirements of Standard No. 103, *Windshield Defrosting and Defogging*, and 104, *Windshield Wiping and Washing*. Standards No. 103 and 104 define three different areas on the windshield and require the wiping system and the defrosting/defogging system of a car to wipe or defrost/defog a prescribed minimum percentage of each of the three areas. Based on your evaluation of a windshield that has a head-up display membrane, you demonstrated that the area of the windshield covered by the membrane represent only a minimal portion of the three areas of the windshield that are required by those standards to be wiped or defrosted/defogged. You further demonstrated that a car could comply with the requirements of Standard Nos. 1-3 and 104 even though the membrane slightly projects into the areas regulated by those standards.; In further support of your position that the head-up display is no located in an area requisite for driving visibility, you provided a comparison of the effects of the head- up display versus the effects of a vehicle's hood design or unretracted head lamp on a driver's forward and downward visibility. In this comparison, you presented information that measure, from the driver's eyepoint, the locations and amount of the driver's forward visibility that would be obstructed by portions of the hood design and by an unretracted head lamp. You then compared the obstruction caused by those design features with the effects of the head-up display on the driver's visibility. The information you provided shows that a vehicle's hood design or an unretracted head lamp can extend as far up in the driver's field of view as the head-up display and provide more obstruction to a driver's forward visibility than the head- up display.; You are correct that while Standard No. 205 and ANS Z26 apply a 7 percent light transmittance requirement to areas of the glazing that are 'requisite for driving visibility,' neither Standard No. 205 nor ANS Z26 specifically defines what areas of the glazing are requisite for driving visibility. In fact, as you pointed out in your letter ANS Z26 specifically defines what areas of the glazing are requisite for driving visibility. In fact, as you pointed out in your letter, ANS Z26 specifically provides, in a footnote to S4.2 of ANS Z26, an exception to the 70 percent light transmittance requirement. The footnote explains that a manufacturer can provide an area on the glazing, such as a shade band, that has a light transmittance of less than 70 percent as long as the areas requisite for driving visibility have a light transmittance of 70 percent. In interpreting the requisite for driving visibility requirement, the agency has not specified a minimum area of the windshield that is requisite for driving visibility. Instead, the agency has said, such as in a letter of February 15, 1974, to Mr. George Nield, that in determining what areas are requisite for driving visibility, the agency will use an approach of determining those areas by reference to vertical heights in relation to the driver's eyes.; (I believe it is important to note that the agency's decision, in th context of shade bands, not to adopt proposed specific size limits on areas of the windshield which could have less than 70 percent transmittance, was based on the conclusion that such a requirement was not necessary because of the voluntary practices of the industry. Thus, although the agency has not adopted a specific requirement, it has been relying on the good faith adherence of the industry to that voluntary practice on shade bands. The agency first proposed a limit on the size and light transmittance of shade bands in a notice published in November 1978(43 FR 51677). In commenting on the notice, several vehicle manufacturers said that such a requirement was not needed since the industry was voluntarily following a Society of Automotive Engineers Recommended Practice (SAE J100, 'Passenger Car Glazing Shade Bands') that established boundaries for shade bands used on glazed surfaces in passenger cars. As NHTSA explained in a notice published in January 1981 (46 FR 40), the agency decided to defer further action on the proposed shade band limit until it gathered additional data on the adequacy of the voluntary industry practice.); After reviewing the information you have submitted, the agency ha concluded that the membrane used in your system is located in an area of the glazing that is not requisite for driving visibility. The agency reached this conclusion based on the specific fact of your particular design and the following considerations. The membrane used in your system is small in size, is located near the bottom edge of the glazing area and toward the corner of the glazing area, and although the membrane has a light transmittance that is less than 70 percent, it is not opaque.; In determining that your head-up display is not located in an are requisite for driving visibility, the agency also considered the effect of the display on a car's ability to meet the requirements of Standard Nos. 103 and 104. Although Standard Nos. 103 and 104 do not define the limits of what areas are requisite for driving visibility, the areas of the windshield covered by the performance requirement of those standards do indicate the agency's concern that, at a minimum, specified portions of those areas of the windshield be clear during inclement weather inclement weather to provide the driver with a view of the road. The information provided with your letter shows that a small portion of the head-up display in your vehicle partially falls within the defined areas, but the vehicle still meets the performance requirements of the standards.; Another factor in the agency's decision was the information in you letter showing a comparison of the effects of the membrane versus the effects of a vehicle's hood design or unretracted head lamp on a driver's forward visibility. The information you provided shows that a vehicle's hood design or an unretracted head lamp can intrude as far up into the driver's field of view as the head-up display and provide more obstruction to a driver's forward visibility than head-up display. This information is an additional indication that the head-up display is not located within an area that is requisite for driving visibility.; Although the agency has concluded that in your particular case you head-up display is not in an area requisite for driving visibility, the agency believes that with the advent of new glazing and other technologies using the windshield, such as the head-up display, it is appropriate to again re-examine the issue for whether to specify the size of the area of the windshield that are requisite for driving visibility. It is apparent that there will be a number of new technologies using the windshield. For example, the March 30, 1987 issue of *Automotive News* carried a news article announcing the development, by PPG Industries and Flight Dynamics, of a 6 inch square holographic display on the windshield.; NHTSA believes that the issues associated with these devices should b addressed in a comprehensive manner. In particular, the agency believes that it needs further information on such issues as whether the areas on the windshield used by these display devices need to have a lower light transmittance value and, if so, what that value should be, where on the windshield the devices can be located, and what limitations should be placed on their size. Addressing these issues in a comprehensive manner by setting general performance requirements applicable to all such devices, regardless of the technology used, will avoid the inconsistencies and possible design specific limitations that might arise if the agency attempts to provide case-by-case interpretations for each specific design. For all these reasons, NHTSA has concluded that it will address these issues through a comprehensive rulemaking action.; You raised one final issue in your letter. You asked that if the agenc concluded that your head-up display does not comply with Standard No. 205, it should regard the noncompliance as a technical one which does not warrant enforcement. Since the agency has concluded that your head-up display does not violate the requirements of Standard No. 205, it should regard the noncompliance as a technical one which does not warrant enforcement. Since the agency has concluded that your head-up display does not violate the requirements of Standard No. 205, the issue is moot.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel

ID: 86-3.31

TYPE: INTERPRETATION-NHTSA

DATE: 05/27/86

FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA

TO: Toshio Maeda

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. Toshio Maeda Executive Vice President & Chief Operating Officer Nissan Research & Development, Inc. P.O. Box 8650 Ann Arbor, MI 48104

Dear Mr. Maeda:

Thank you for your letter of April 11, 1986, requesting an interpretation of the comfort and convenience requirements of Standard No. 208, Occupant Crash Protection. Your specific question is whether the retraction requirements of S7.4.5 of the standard apply only to the front outboard seating positions. As explained below, the answer is yes.

The April 12, 1985 notice proposed changes to the comfort and convenience requirements in response to petitions for reconsideration. In the case of the retraction requirements, the proposed language of S7.4.5 said that the requirement would only apply to a safety belt system installed at the "front outboard designated seating position." In the November 6, 1985 final rule adopting the retraction requirement, the agency dropped the reference to the "front outboard seating position." However, S7.4.5 still referred to conducting a compliance test on a test dummy which has been positioned "in accordance with S10." S10, in turn, references the test dummy positioning requirements of S8.1.11. S8.1.11.1 and S8.1.11.2 provide for positioning test dummies in the front outboard seating positions. Thus, the minor change in the language of the requirements did not change the applicability of the requirement. However, to eliminate any possible ambiguity about the application of the retraction requirement, the agency is planning to amend S7.4.5 to provide explicitly that it only applies to the front outboard designated seating positions.

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

Sincerely,

Erika Z. Jones Chief Counsel April 11, 1986 Ref : W-159-H

Ms. Erika Jones Chief Counsel National Highway Traffic Safety Administration 400 7th St., S.W. Room 5219 Washington, D.C. 20590

Dear Ms. Jones:

Re: REQUEST FOR INTERPRETATION 49 CFR Part 571 Docket No. 74-14; Notice 42 Seat Belt Comfort and Convenience

On behalf of Nissan Motor Co., Ltd. of Tokyo, Japan, Nissan Research & Development, Inc. herewith requests interpretation of a somewhat ambiguous phrase in the NHTSA's final rule on the performance requirements for seat belt assemblies (Federal Motor Vehicle Safety Standard 208).

S571. 208. S7.4.5, Retraction, reads, in part, ". . .the torso and lap belt webbing of any of those seat belt systems shall automatically retract when the adjacent vehicle door is in the open position, or when the seat belt latchplate is released, to a stowed position." (Emphasis added)

Question:

In the case of a 2-door vehicle, what would be considered the "adjacent" door for either the rear outboard seat or the rear center seat? Or is the retraction performance requirement intended to be applicable to rear seating positions at all?

Since the effective date for this requirement is already less than six months away, any urgency with which you can address our concern is highly appreciated.

If you have any questions, please contact Mr. Tomoyo Hayashi of my Washington, D.C. staff at (202) 466-5284.

Thank you very much. Again, we would be grateful for a prompt response.

Respectfully submitted,

Toshio Maeda Executive Vice President & Chief Operating Officer

TM:TH:mab cc) Mr. Steve Oesch, Chief Counsel Office, NHTSA

ID: nht94-2.71

TYPE: Interpretation-NHTSA

DATE: May 6, 1994

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Jeffrey D. Shetler -- Manager of Government Relations, Kawasaki Motors Corp. U.S.A.

TITLE: None

ATTACHMT: Attached to letter dated 2/7/94 from Jeffrey D. Shetler to the Associate Administrator for Enforcement, NHTSA (OCC-9697)

TEXT:

This is in reply to your letter of February 7, 1994, to the Associate Administrator for Enforcement requesting an interpretation of Federal Motor Vehicle Safety Standard No. 108. So that we may serve you better in the future, please note that the Office of Chief Counsel is the one to which requests for interpretations should be addressed.

You have asked whether the "proposed application of a projector beam headlamp to a motorcycle" will meet the requirements of Standard No. 108. In this headlamp "the projector beam (lower beam) is located on the left side and the high beam is on the right side." You continue by saying that "the outer lens of the headlamp assembly is symmetrically positioned about the vertical centerline," and you ask whether the headlamp complies with the requirements of Table IV of Standard No. 108.

Table III of Standard No. 108 requires a motorcycle to have at least one headlamp. Table IV requires the headlamp to be located "on the vertical centerline, except that if two are used they shall be symmetrically disposed about the vertical centerline." The device you describe contains the upper and lower beams in one housing and hence is a single headlamp. Although your projector beam headlamp would be mounted literally on the vertical centerline, the beams provided by the headlamp are located on eit her side of the centerline and are therefore asymmetrical in relation to the centerline of the motorcycle when either beam is activated. A redesign of the lamp so that its vertical centerline becomes its horizontal centerline and Line A becomes the vert ical centerline would be a configuration that meets Table IV since both beams of the single headlamp would then be located on the vertical centerline. SAE J584 does not specify the location of one beam in relation to the other for dual beam motorcycle h eadlamps, i.e., whether one beam is to be mounted above or below the other.

Your second question concerns an interpretation of S5.1.1.23. This paragraph provides an alternative for motorcycles to the headlamps specified by Table III, and allows a motorcycle to be equipped with "one half of any headlighting system specified in S 7 which provides both a full upper beam and full lower beam, and where more than one lamp must be used, the lamps shall be mounted vertically, with the lower beam as high as practicable." You have asked whether this means that your proposed headlamp "sh all be mounted on the upper half and the high beam shall be on the lower half when using one half of any headlighting system specified in S7," or "is our proposed layout in the attachment acceptable?"

As I have explained, your proposed layout in the attachment is not acceptable under Table IV without reorientation. The headlighting systems specified in S7 are those intended for four-wheeled motor vehicles (other than trailers). As we understand it, your proposed headlamp has been developed as a headlamp system for motorcycles and not as half of a headlamp system for vehicles other than motorcycles. Because motorcycle photometrics differ from those for vehicle other than motorcycles, your proposed headlamp could not be half of a system specified in S7 which may be used on motorcycles as an alternative to the headlamps specified by Table III.

ID: 15647.ztv

Mr. Michael J. Rood
Vice President, Engineering
Safe-Lite Mfg. Co.
6230 Gross Point Road
Niles, IL 60714

Dear Mr. Rood:

This is in reply to your letter of July 23, 1997, to Taylor Vinson of this Office, asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108. We apologize for the delay in responding, but your letter presented unique questions which took some time to resolve to the agency's satisfaction.

There are three aspects of reflex reflector conspicuity treatment that you wish us to address, to clarify questions asked by owners who wish to retrofit their trailers, as well as by manufacturers of new trailers. Retrofitting of trailers manufactured before December 1, 1993, of course, is not subject to the requirements of Standard No. 108.

As you point out, S5.7.2.2(a) allows the use of reflex reflectors as a conspicuity alternative to S5.7.1.4 "in the same locations and in the same length in which retroreflective sheeting is required. . . ." You believe that because reflex reflectors cannot be trimmed, it is impossible that reflex reflectors can comply in some instances with the literal requirement of S5.7.2.2 that they be applied "in the same length" as retroreflective sheeting to meet conspicuity requirements.

The conspicuity requirements of Standard No. 108, including the provisions referring to practicability, are stated in terms of sheeting material. Each reflex reflector used to fulfill conspicuity requirements must have photometric performance equivalent to that of a 100 mm length of sheeting material, and the conspicuity treatment may then be implemented using reflex reflectors with a center-to-center spacing not greater than 100 mm. Conspicuity treatments using one reflex reflector as an alternative to 100 mm of sheeting material would be equivalent in minimum performance and nearly identical in reflective appearance to a treatment using sheeting material.

The trailer manufacturer has the choice of using either reflex reflectors or sheeting material. However, reflex reflectors could not be used to comply with the standard if they cannot replicate a complying sheeting material installation. For example, S5.7.1.4.2(a) requires the conspicuity treatment to originate and terminate "as close to the front and rear as practicable," and that it need not be continuous as long as "the spaces are distributed as evenly as practicable." If sheeting material would terminate closer to the front or rear than is possible with reflex reflectors on a particular trailer, or if it results in a more even distribution of spaces, then sheeting material must be used to meet the practicability provisions. There may be instances when sheeting material is better than reflex reflectors in taking account of ribs and obstructions on the trailer body in marking the overall length of the vehicle, or when its use would result in lesser gaps in the treatment than use of reflex reflectors.

Similarly, if a trailer manufacturer determines that it may use reflex reflectors as a conspicuity treatment, it must use a single reflector of 100 mm length rather than a bar of reflectors of 300 mm if the single reflector would more closely mark the extreme width or length of the trailer or result in smaller gaps.

Underride Protection Devices

Paragraph S5.7.1.4.1(c) requires a strip of retroreflective sheeting in alternating colors to be installed across the full width of the horizontal member of the rear underride protection device.

You have enclosed sample reflex reflector bars that are 12 inches (approximately 300 mm) in length. You point out that, unlike retroreflective sheeting, reflex reflectors cannot be trimmed in application. Assuming that the underride protection bar is 90 inches (7' 6") in length, you present two options. In the first option, you would center a white reflex reflector on the bar, and work outward with alternating red and white reflectors (seven in all), which would leave 3 inches of uncovered surface at both ends of the underride bar. In the second option, you would work inward from reflectors placed at the end of the underride bar, distributing the 6 inches of uncovered surface evenly between reflectors. We understand that this means that seven reflectors would be provided, with only 1 inch of space between adjacent reflectors.

The standard requires reflex reflectors to be used "in the same locations and in the same length in which retroreflective sheeting is required...with the center of each reflector not more than 100 mm (4 in) from the center of each adjacent reflector." The underride protection device in question would have been treated with 90 inches of sheeting material, and an exact replacement using reflex reflectors would require 22 reflex reflectors with each reflector replacing 4 inches of sheeting material. However, Standard No. 108 does not recognize fractional reflex reflectors because, unlike sheeting material, they are non-homogenous indivisible units. Nor does it assume that there will be sufficient space to apply a greater number of whole reflex reflectors. Therefore, the agency has decided that the "full width" requirement can be met by using the greatest number of whole reflectors (on a basis of one reflector per 4 inches) that will fit in the length required for sheeting material. Since both of the options you propose use 21 rather than 22 reflex reflectors, neither would satisfy the standard. Given the space limitations on an underride guard, you would have to supplement the bars of three reflectors with some double or single reflectors to achieve acceptable coverage. Since the maximum cumulative space between reflectors would always be less than 4 inches per element of the conspicuity treatment, the distribution of spaces would have little practical significance. However, arrangements that mark the actual full width are always preferable to those that only approximate it.

Rear Width of a Trailer

Similarly, the conspicuity treatment specified in S5.7.1.4.1(a) is to be applied "across the full width of the trailer." You ask how a continuous pattern of alternating red and white reflex reflectors are to be applied in multiples of 12-inch segments when there are rear door hardware obstructions that do not allow it.

You suggest that if the linear space between hardware obstructions is between 12 and 24 inches, then one reflex reflector can be centered in this space provided that it is a different color than its two neighbors. If the space is between 24 and 36 inches, two reflex reflectors could be centered, again preserving a pattern of alternating colors. This scheme would apply in successive 12-inch increments with the reflectors applied at both ends of the completed scheme, "positioned as close to each end as practicable."

As in the underride interpretation above, the minimum number of reflex reflectors needed to implement an element of conspicuity treatment is the number of mm (or inches) of sheeting material that would have been used, divided by 100 mm (or 4 inches) and rounded down to the greatest whole number. In general, it would be a matter of chance if the minimum number of reflex reflectors could be arranged in a single line when obstructions are present, especially when the reflectors are combined in bars of three. However, element 1 of the rear trailer conspicuity treatment (S5.7.1.4.1(a)) is not required to be located on the same parallel plane; obstructions can be cleared by mounting some of the reflex reflector bars above or below obstructions to obtain a greater number of reflex reflectors in the treatment. Of course, the treatment must mark the full width of the body in the same manner as a treatment with sheeting material.

Unique Trailer Side Walls and Rub Rails

The required conspicuity treatment for trailer sides is set forth in S5.7.1.4.2(a). It requires that conspicuity treatment originate and terminate as close to the front and rear as practicable, and that a strip of retroreflective sheeting need not be continuous as long as not less than half of the length of the trailer is covered and the spaces are distributed as evenly as practicable.

You bring to our attention the fact that the distance from one outer rib to another on the side of some "plate" trailers could vary from 5 to 42 inches, and that your reflector will not fit into a section narrower than 12 inches. You would provide reflex reflectors in alternate color segments to cover not less than half the trailer length, even though there might be a space between some segments. This treatment would start and finish as close to both ends of the trailer "as practicable," and meet the requirement of S5.7.1.3(c) that neither color in the aggregate exceed two-thirds of the total provided to mark the sides.

As noted above, the practicability requirements for the placement and distribution of the retroreflective material in S5.7.1.4.2(a) were conceived and expressed in terms of a treatment using sheeting. If these requirements are more closely fulfilled using sheeting material, then sheeting material must be used. Although either sheeting material or reflex reflectors could be used on trailers with uninterrupted sills, it may be impossible to use triple reflector bars exclusively as a complying conspicuity treatment on the side of a trailer with ribs. Depending on the distance between the ribs, trailer manufacturers would be expected to use single reflectors or bars of two reflectors (or simply to use sheeting material) for that element of the conspicuity treatment.

If you have further questions, you may phone Taylor Vinson at 202-366-5263.

Sincerely,
John Womack
Acting Chief Counsel
ref:108
d.5/6/98