[Federal Register Volume 59, Number 242 (Monday, December 19, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-31089]


[[Page Unknown]]

[Federal Register: December 19, 1994]


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DEPARTMENT OF TRANSPORTATION
[Docket No. 94-65; Notice 2]

 

General Motors Corporation; Decision That Noncompliance With 
Standard No. 108 is Inconsequential to Safety

    General Motors Corporation (GM) of Warren, Michigan, determined 
that some of its vehicles failed to comply with 49 CFR 571.108, Federal 
Motor Vehicle Safety Standard (FMVSS) No. 108, ``Lamps, Reflective 
Devices, and Associated Equipment,'' and filed an appropriate report 
pursuant to 49 CFR Part 573, ``Defect and Noncompliance Reports.'' GM 
also applied to be exempted from the notification and remedy 
requirements of 49 U.S.C. Chapter 301 - ``Motor Vehicle Safety'' on the 
basis that the noncompliance is inconsequential to motor vehicle 
safety.
    Notice of receipt of the application was published on July 29, 
1994, and an opportunity afforded for comment (59 FR 38660). This 
notice grants the application.
    Figure 10 of FMVSS No. 108, referenced at S5.1.1.27(a)(3), lists 
the photometric requirements for center high-mounted stop lamps 
(CHMSLs). GM produced two different vehicle populations which do not 
meet the photometric requirements of Figure 10. The first population of 
vehicles, approximately 23,695 Cadillac Deville and Deville Concours 
produced between the start of the 1994 model year and November 19, 
1993, had their CHMSLs ``framed'' in the rear window by a 27 mm high 
opening in the blackout paint at the lower edge of the rear window. A 
vertical shift in the installed position of the rear window, compounded 
by build variation, caused the painted frame around the CHMSL on each 
of these vehicles to obscure the photometric performance at the 5D 
line.
    The second population of vehicles, approximately 65,403 Cadillac 
Deville and Deville Concours produced between November 19, 1993, and 
May 4, 1994, has a narrower painted ``frame'' around the CHMSL in the 
rear window. The painted frame width was reduced due to an engineering 
change by 5 mm to a width of 22 mm. The shift in installed position and 
build variation noted above obscured the 5D line on some of these 
vehicles. Other vehicles within this second population had the 10U line 
obscured as a result of build variation. In no case were both the 5D 
and 10U lines obscured.
    GM supported its application for inconsequential noncompliance as 
discussed below. GM also submitted diagrams and tables in support which 
are available for review in the NHTSA docket. According to GM:

    GM performed a dimensional analysis on a 51-vehicle sample to 
determine where the paint opening on the rear glass was in relation 
to the CHMSL. (Note that no CHMSL could be obscured at both the top 
and bottom by the paint line.) For those vehicles with the CHMSL 
obscured at the bottom of the lamp, the analysis, which approximates 
a normal distribution, indicated that 1.5 percent of the entire 
population of vehicles, or approximately 1,336 vehicles, could 
experience sufficient obscuration to render the vehicles out of 
compliance with FMVSS 108, with a 4.6 mm worst case infringement at 
the bottom of the CHMSL. However, a photometric test conducted on a 
CHMSL with a 4.6 mm mask at the bottom of the lamp established that 
for the test points that fell on and below horizontal, i.e., for the 
points on the H and 5D lines, photometric output exceeded FMVSS 108 
requirements by an average of 75 percent. * * * Even on the 5D line, 
all five test points were within 20 percent of FMVSS 108, with the 
worst performance at 5D-5R, where the tested value was 23.0 candela, 
or 82 percent of the 25.0 candela requirement.
    As for those vehicles with the CHMSL obscured at the top of the 
lamp, the sample suggests that 15 percent of the second population 
described above, or 9,810 vehicles, could be obscured to the point 
that they would fail to comply with FMVSS 108, with a worst case 
infringement at the top of the CHMSL of 4.5 mm. However, a 
photometric test on a CHMSL with a 4.5 mm mask at the top of the 
lamp demonstrated that while test values on the 10U line fall below 
required levels, the lamp provides approximately 75 percent more 
light output above horizontal (at the 5U and 10U lines combined) 
than required by FMVSS 108. (Photometric output of the obscured lamp 
as a whole approximated 33 percent more than FMVSS 108 
requirements.) * * *
    To determine the extent of the noncompliance for those vehicles 
obscured at the top of the CHMSL, GM plotted data from a series of 
photometric tests of 10U-V (the worst performing test point), with 
varying degrees of obscuration, against performance to the FMVSS 108 
requirement. The result approximates a linear function of 
obscuration versus photometric output, and suggests that subject 
CHMSLs obscured less than 3.07 mm will fall within 20 percent of the 
values listed in FMVSS 108 * * *. Applying the distribution 
determined from GM's 51-vehicle sample to that, approximately 76 
percent, or 7,456 of the 9,810 vehicles described above, will 
provide photometric output within 20 percent of the FMVSS 108 
requirements at 10U.
    As acknowledged in NHTSA's notices granting other similar 
Petitions for Determination of Inconsequential Noncompliance, a 
change in luminous intensity of approximately 25 percent is required 
before the human eye can detect a difference between two lamps. 
(See, e.g., Notice granting Petition by Subaru of America (56 Fed. 
Reg. 59971); and Notice granting Petition by Hella, Inc. (55 Fed. 
Reg. 37601, at 37602).) Given this, the 7,456 vehicles obscured less 
than 3.07 mm at the top of the CHMSL, as well as the 1,336 vehicles 
obscured at the bottom of the lamp, do not compromise motor vehicle 
safety since the noncompliance is imperceptible to the naked eye and 
the overall light at the outer zones (H & 5D; 5U & 10U) exceeds the 
FMVSS requirements.
    Although the degradation in light output for the 2,354 remaining 
vehicles would likely be discernible in a subjective side-by-side 
comparison with a conforming lamp, visible light is still emitted at 
the 10U line. Moreover, GM's photometric analysis indicates that 
even with a worst case obscuration of the 10U line, the 16 candela 
required light output at 10U-V is supplied at 8U-V. Given that and 
the location of the CHMSL on the subject vehicles, these CHMSLs 
perform their intended function in a manner virtually 
indistinguishable from CHMSLs on other vehicles that fully comply 
with FMVSS 108, as demonstrated below.
    The specified range of required photometric output for CHMSLs 
from 10U to 5D was developed from SAE J186a and is presumably 
intended to allow manufacturers latitude in locating CHMSLs for the 
myriad of vehicle designs, while assuring that sufficient light is 
available to signal drivers of following vehicles. For example, the 
10U photometric angle helps to assure that drivers of large vehicles 
(such as medium and heavy duty trucks), perceive a preceding 
vehicle's CHMSL signal, regardless of the size of that vehicle or 
the CHMSL's mounting location.
    However, the Cadillac CHMSL is mounted relatively high in 
relation to other passenger vehicles on the road, and is located in 
the passenger compartment, not on the deck lid. Therefore, the light 
emitted from the Cadillac CHMSL at the upward-most photometric 
angles is not as critical as light at those same angles emitted from 
vehicles with CHMSLs located rearward and closer to the ground.
    To illustrate this point, GM compared the Cadillac CHMSL to the 
CHMSL on the Mazda Miata. The Miata sits comparatively low to the 
ground, and its CHMSL is mounted low on the deck lid. After 
determining that the 16 candela photometric output required by FMVSS 
108 at 10U-V is provided by the Cadillac CHMSL with a worst case 
intrusion at 8U, GM overlaid the mounting location and 10U line of 
the Mazda Miata on a drawing of the Cadillac CHMSL and 8U line, 
placing the rear of the vehicles at the same location ***. The 
result shows that the 8U and 10U lines cross 37.4 feet behind the 
vehicles and 9.3 feet above the ground; until that point, the 
Cadillac CHMSL provides more light to the extreme up positions than 
does the fully compliant Miata CHMSL.
    GM then overlaid on the drawing of the Cadillac and Miata CHMSLs 
the average eye ellipse location for heavy duty trucks (cab over) 
and medium duty trucks, which are 7.7 feet and 6.8 feet from ground, 
respectively ***. The fact that these eye-ellipse locations fall 
well below the 9.3 feet intersection point of the Cadillac CHMSL 8U 
line and the Miata CHMSL 10U line demonstrates that the Cadillac 
CHMSL provides sufficient usable light to all following drivers.
    That is, because GM designed the subject vehicles with a high 
and forward CHMSL mounting location, drivers sitting at the highest 
positions from the road will see the photometric output intended by 
the Standard for the upward-most angles, regardless of (worst case) 
obscuration of the lamp. The Cadillac CHMSL actually provides a 
greater area of visible light than a vehicle with a fully compliant 
lamp that is mounted lower and rearward.
    There are vehicles with fully compliant CHMSLs, at mounting 
locations approximating that of the Cadillac, that cast more light 
in the upper extreme areas behind the vehicle. However, *** a 
compliant CHMSL (mounted at the same location as the Cadillac CHMSL) 
will provide only an additional triangular area six feet in length 
and eleven inches high of potentially usable light, starting 20 feet 
behind the vehicle. This small area is only visible to drivers of 
the largest vehicles. Given that and negligible decrease of light 
emitted by the Cadillac CHMSL, GM believes that the Cadillac CHMSL 
will perform its intended function effectively identical to fully 
compliant CHMSLs mounted at the same location. Furthermore, as 
demonstrated above, the Cadillac CHMSL provides more light at the 
extreme up angles than other fully compliant CHMSLs mounted lower 
and rearward. These factors, together with the small number of 
Cadillacs involved, support GM's belief that the CHMSLs at issue 
here will not have an adverse affect on motor vehicle safety.
    The CHMSLs otherwise meet all FMVSS 108 requirements, and the 
photometric output of the stop lamps, which are supplemented by the 
CHMSL, far exceeds FMVSS 108 minimum requirements.
    GM is not aware of any accidents, injuries, owner complaints or 
field reports related to this issue.
    General Motors believes that the noncompliance that results from 
a small obstruction of the CHMSL by blackout paint on the rear 
window is inconsequential as it relates to motor vehicle safety. In 
consideration of the foregoing, General Motors petitions that it be 
exempted from the recall and remedy provisions of the Act for this 
specific noncompliance with FMVSS 108.
    No comments were received on the application.

    In presenting its arguments, GM has separated its noncomplying 
vehicles into two categories, those in which the diminished luminous 
intensity of the CHMSL might be discernible, and those in which it 
might pass unnoticed.
    The noncompliance that is most likely to have a consequential 
effect on safety is the degradation in light output that ``would likely 
be discernible in a subjective side-by-side comparison with a 
conforming light.'' This appears to occur only in vehicles where 
compliance along the 10U line is affected. GM argues that, in the worst 
case, there is full compliance along a hypothetical 8U line, and that 
``visible light is still emitted at the 10U line.'' Thus, the effect on 
safety of a diminished luminous intensity in the two degrees between 8U 
and 10U must be considered. GM has pointed out the obvious, that the 
mounting height of the CHMSL is not standardized among vehicles, and 
that factor, in addition to the differing eye height of following 
drivers and the angle of approach, results in an infinite number of 
perceptions. The result of this is that, in some instances, the 
noncompliant Cadillac CHMSL ``actually provides a greater area of 
visible light'' than a complying CHMSL ``that is mounted lower and 
rearward.'' With respect to the two-degree area of noncompliance, a 
complying lamp ``will provide only an additional triangular area six 
feet in length and eleven inches high of potentially usable light, 
starting 20 feet behind the vehicle.'' Terming this a ``small area,'' 
GM submits that it ``is only visible to drivers of the largest 
vehicles.''
    NHTSA reviews noncompliances involving performance failures with 
special concern, and it has done so here. But it has concluded that GM 
has met this concern with respect to the possible effect of this 
specific noncompliance upon motor vehicle safety, and has decided that 
it does not affect safety in a consequential manner.
    With respect to the remaining noncompliances, those that might not 
be discernible to the naked eye, GM cites NHTSA's previous grants of 
inconsequentiality petitions based upon the agency's conclusion that a 
change in luminous intensity of approximately 25 percent must occur 
before the human eye can discern a difference. Three-quarters of GM's 
noncompliant lamps probably are said to have a noncompliance in 
luminous intensity that does not exceed 20 percent of Figure 10's 
specifications.
    GM has correctly noted NHTSA's position on the effect of deviations 
in luminous intensity. Additional support for that position has been 
provided in a recent report ``Driver Perception of Just-Noticeable 
Differences of Automotive Signal Lamp Intensities'' (DTNH22-92-D-07002) 
which found that 25 percent is a reasonable criterion for use in 
inconsequentiality decisions.
    Accordingly, the applicant has met its burden of persuasion that 
the noncompliance herein described is inconsequential to safety, and 
General Motors Corporation is hereby exempted from the notification 
requirements of 49 U.S.C. 30118 and the remedy requirements of 49 
U.S.C. 30120.

    (49 U.S.C. 30118, 30120; delegations of authority at 49 CFR 1.50 
and NHTSA Order 800-2)

    Issued on: December 13, 1994.
Barry Felrice,
Associate Administrator for Rulemaking.
[FR Doc. 94-31089 Filed 12-16-94; 8:45 am]
BILLING CODE 4910-59-P