[Federal Register Volume 63, Number 134 (Tuesday, July 14, 1998)]
[Proposed Rules]
[Pages 37820-37827]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-18704]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. NHTSA-98-4028: Notice 4]
RIN 2127-AC85
Federal Motor Vehicle Safety Standards; Glazing Materials
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).
ACTION: Withdrawal of notice of proposed rulemaking.
-----------------------------------------------------------------------
SUMMARY: This notice withdraws a proposal in which the agency
considered amending Federal Motor Vehicle Safety Standard No. 205,
Glazing materials, to revise its light transmittance requirements. The
amendments would have specified a new procedure for testing the light
transmittance of glazing samples. Instead of specifying that they be
tested at the currently specified 90 degree angle, the standard would
have specified that they be tested at the acute angle at which the
glazing would be installed in the vehicle (the rake angle). The
amendments also would have added light transmittance requirements for
light trucks, vans, sport utility vehicles, and buses of less than
10,000 pounds gross vehicle weight rating (GVWR), and specified
different transmissibility requirements for the various windows.
After reviewing the available information, NHTSA has decided to
withdraw this proposal. The reasons for taking this action include the
following: the cost impacts of testing at the installed angle pursuant
to the proposed new procedure would not be adequately offset by the
potential safety benefits of increased visibility if glazing continues
to be installed at current rake angles; the practical limits imposed by
concerns about visual distortion will prevent rake angles from
increasing; the agency does not want to prohibit the use of the best
present solar windshield glazing in order to achieve slight differences
in effective light transmittance at current rake angles; the agency
wishes to better define the relationship between light transmittance
and highway safety before it establishes transmittance levels for
various vehicle windows; and without controlling for the installed
angle of the glazing, setting specific transmittance levels would not
consistently and predictably result in improved light transmittance.
Another reason for withdrawing this proposal to establish light
transmittance levels for additional classes of motor vehicles concerned
the fact that the proposed transmittance levels were premised upon
adopting the proposed new test method. Since the agency is not adopting
the new method, it can not adopt transmittance levels selected on the
basis of that method.
FOR FURTHER INFORMATION CONTACT: For technical issues: Richard Van
Iderstine, Office of Crash Avoidance Standards, National Highway
Traffic Safety Administration, 400 Seventh Street, S.W., Washington,
D.C., 20590. Telephone: (202) 366-5280.
For legal issues: Paul Atelsek, NCC-20, Rulemaking Division, Office
of Chief Counsel, National Highway Traffic Safety Administration, 400
Seventh Street, SW., Washington, D.C. 20590 (202) 366-2992.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Background
A. The current standard
B. Previous events related to this rulemaking
1. Request for Comments
2. Report to Congress
3. Court case against tint film installers
II. Notice of Proposed Rulemaking (NPRM)
A. Summary of issues analyzed
B. The proposed rule
1. Test procedure
2. Light transmittance levels
3. Vehicles covered
4. Compliance by multi-stage manufacturers
5. Amendments to the language of FMVSS No. 205
III. Comments on the NPRM
A. Tint film industry
B. Medical commenters
C. Safety groups
D. Law enforcement community
E. Manufacturers of motor vehicles
F. Glazing manufacturers
IV. Analysis of issues
A. Line-of-sight measurement of glazing transmittance
B. Proposed transmittance values
V. Agency decision
VI. ``Reissuance'' of Standard No. 205
I. Background
A. The Current Standard
Federal Motor Vehicle Safety Standard No. 205, Glazing Materials
(49 CFR 571.205), specifies performance requirements and permissible
locations for the types of glazing that may be installed in motor
vehicles. The standard incorporates by reference American National
Standards Institute (ANSI) Standard Z26.1, ``Safety Code for Safety
Glazing Materials for Glazing Motor Vehicles Operating on Land
Highways,'' as amended through 1980 (Z26). The requirements in Z26 are
specified in terms of performance tests that the various types, or
``items,'' of glazing must pass.
One of the tests is for luminous, or light, transmittance. This
test measures the regular (parallel) transmittance of a sample of the
glazing, in terms of the percentage of incident light that passes
through the glazing. During the test, light strikes the glazing at a 90
degree angle. To pass the test, the glazing must allow 70 percent of
the incident light to pass through.
The amount of light transmitted through vehicle glazing affects the
ability of the driver to see objects on the road. Low light
transmittance can make it difficult to detect low contrast objects,
such as pedestrians, whose luminance and coloring causes them to blend
with the background of the roadside environment. The effect of low
light transmittance levels on the driver's vision is most pronounced at
dusk and night when the ambient light level is low. This is because the
``contrast sensitivity'' of the eye diminishes as the overall
brightness of the scene decreases. This lower contrast sensitivity
makes it especially difficult to discern low contrast objects. This
problem is most acute for older drivers who have poorer contrast
sensitivity. Contrast sensitivity declines by a factor of two about
every 20 years after age 30. Thus, older drivers have poorer dusk and
night vision.
The light transmittance requirements must be met by all glazing
installed in windows that are ``requisite for driving visibility'' (see
Z26, table 1). In a longstanding interpretation of this term, NHTSA has
determined that all windows in a passenger car, with limited exceptions
not relevant here, are considered requisite for driving visibility.
For buses, trucks, and multipurpose passenger vehicles (MPV's),
glazing that meets the 70 percent light transmittance requirements is
required in the windshield, the windows to the immediate left and right
of the driver, and any rear or rear side windows that are requisite for
driving visibility. The agency has not issued an interpretation
specifying which rear or rear side windows are requisite for driving
visibility. In rear windows in buses, trucks, and MPV's that are not
requisite for driving visibility, items of glazing that are not subject
to the 70 percent
[[Page 37821]]
light transmittance requirements may be installed.
As mentioned above, light transmittance of glazing is measured in a
laboratory test with the glazing perpendicular to the measuring device,
instead of at the angle at which it is mounted in the vehicle (called
the ``rake'' angle). Glazing transmits the maximum amount of light when
it is mounted perpendicular to the line of sight (i.e., at an angle of
90 degrees), as in the current Standard No. 205 test. As the mounting
angle decreases, the amount of light transmitted by the windshield also
decreases. For example, windshield glazing with a light transmittance
of 73 percent when tested perpendicular to the measured light beam,
would have a light transmittance of about 65 percent when tested at a
typical windshield rake angle of 60 degrees. (A rake angle of 60
degrees from the vertical axis places the sample at a 30 degree angle
with respect to the horizontal light beam representing the line of
sight.)
B. Previous Events Related to This Rulemaking
1. Request for Comments
NHTSA received four petitions for rulemaking to amend Standard No.
205 ``to permit 35 percent minimum luminous transmittance plastic film
on glazing in the side and rear locations of passenger cars.'' If that
film were placed on glazing with 70 percent light transmittance, the
combined effect would be to allow an overall transmittance of 24.5
percent.
NHTSA granted the petitions and issued a Request for Comments on
July 20, 1989 (54 FR 30427). NHTSA received over 100 comments from a
variety of groups in response to the Request for Comments. The comments
are available for public review in Docket 89-15, Notice 1.
NHTSA received many comments from police departments and other
safety groups opposing darker tinting. These commenters were concerned
about the ability of the police to see occupants and objects in
vehicles with darker tinting and about traffic safety risks. Some
commenters opposed any reduction in the required level of window light
transmittance under Standard No. 205 because they believed the current
level of light transmittance was necessary, particularly for older
drivers and for night driving. Domestic automobile manufacturers
advocated more research to define driving visibility needs and opposed
allowing additional tinting unless research shows that driver and
police safety would be maintained. They further indicated that they
were pursuing technological advances to reduce solar loads without
reducing safety.
Some commenters were supportive of the petitions. Three German
automobile manufacturers and a European research institute working on
visibility issues supported allowing darker tinting for rear and rear
side windows, but opposed it for front side windows. The petitioners
and other commenters stated that darker tinting reduces solar heat
transmittance and would increase the comfort of vehicle occupants and
reduce chlorofluorocarbon (CFC) emissions, thus providing an
environmental benefit.
2. Report to Congress
The House Appropriations Committee requested NHTSA to report to
the House and Senate Committees on Appropriations on the adequacy of
current regulations governing window tinting. In March of 1991, NHTSA
issued a Report to Congress which concluded:
The light transmittance of windows on new passenger cars
complying with Standard No. 205 does not present an unreasonable risk
of crash occurrence. While it is not possible to quantify the safety
effects of lowering the light transmittance through window tinting,
data indicate that extensive tinting can reduce the ability of drivers
to detect objects, which could lead to an increase in crashes.
A change in the way light transmittance is measured in
Standard No. 205 may be appropriate. Performing the test at the angle
the glass is installed on the vehicle, along the driver's line of
sight, is more representative of the real world. Light transmittance
requirements could be based on the light transmitting performance of
production cars since, as noted above, windows in these vehicles
provide light transmittance which does not present an unreasonable risk
of crash occurrence.
Because light trucks, including pick-ups, vans and sport
utility vehicles, and buses with a GVWR of less than 10,000 pounds
(collectively referred to in this document as light trucks) are now
used more as personal transportation vehicles, it may be appropriate to
harmonize light transmittance of these vehicles with the requirements
of passenger cars.
The benefits of tinting do not appear great enough to
justify any loss in safety that may be associated with allowing
excessive tinting of windows. Further, technology already being applied
in production car windows can reduce the heat build up in the occupant
compartment while preserving the driver's visibility. A greater
reduction in the ability of drivers to see through the windshield, rear
window or front side windows would be expected to decrease highway
safety.
3. Court Case Against Tint Film Installers
NHTSA initiated an enforcement case against aftermarket tint film
installers who were installing tint film which results in less than 70
percent light transmittance, thereby making safety features installed
pursuant to the requirements of Standard No. 205 inoperative. The U.S.
District Court of the Middle District of Florida ruled against the
agency, holding that Standard No. 205 was not enforceable against
window tinting businesses because the agency did not issue a ``new and
revised'' Federal Motor Vehicle Safety Standard pursuant to the second
sentence of Section 103(h) of the National Traffic and Motor Vehicle
Safety Act (Safety Act, since codified at 49 USC Chapter 301). United
States v. Blue Skies Projects, Inc., 785 F.Supp 957, (M.D. Fla., 1991).
II. Notice of Proposed Rulemaking (NPRM)
NHTSA published an NPRM on January 22, 1992 (57 FR 2496). In the
NPRM, the agency first analyzed the issues presented by the petition,
the Report to Congress, and public comments submitted in response to
the Request for Comments. Then the agency proposed a number of
substantive changes in the light transmittance requirements.
A. Summary of Issues Analyzed
The agency examined the suggested benefits of tinting. These
included reduction in heat and energy transmittance, reduction in
excessive amounts of visible light, reduction in glare, reduction in
lacerations and ejections, and increased privacy and aesthetic
concerns. NHTSA tentatively concluded that all of these benefits were
minimal, could be better achieved through other means such as
sunglasses, or could be achieved equally well using untinted film.
NHTSA also examined the potential effect on highway safety of
various levels of light transmission. NHTSA generally concluded in its
report to Congress that excessive window tinting reduced the ability of
drivers to perceive the driving environment, particularly for older
drivers and drivers with spectacles. The reduction was most pronounced
when viewing low contrast objects, especially at dusk or at night.
[[Page 37822]]
NHTSA also examined the necessity for good visibility through
particular windows. Front side windows are necessary for viewing
intersections, making lane changes with peripheral vision, viewing the
side mirrors, and for making eye contact with other drivers and
pedestrians who wish to cross the driver's path. Rear side windows are
necessary for viewing intersections with acute angles, and for merging
onto limited access highways. Rear windows are necessary for merging,
backing, and allowing other drivers to see the center high mounted stop
lamps.
In addition, the agency examined research studies on the issue of
tinting safety. Based on three research studies on the relationship
between tinting and object detection, NHTSA concluded that the ability
to detect objects decreases as the tint level increases. Although NHTSA
concluded that low levels of light transmittance are a safety problem,
it was unable to define the magnitude of that problem in terms of a
numerical relationship between vehicle collisions and tinting levels.
The agency also noted studies showing that 35 percent light
transmittance tinting would make it difficult for police officers to
detect objects, including a drawn weapon, inside a vehicle during
traffic stops.
B. The Proposed Rule
After considering these issues, the agency proposed to amend
Standard No. 205 in two major ways. First, to account for the effect of
rake angle on light transmittance, NHTSA proposed to change the test
procedure so that the glazing sample's luminous transmittance would be
viewed and measured at the maximum installation angle (i.e., the
maximum nominal rake angle at which glazing could be installed in a
motor vehicle). Second, the agency proposed to specify different light
transmittance levels for the various windows in vehicles.
1. Test Procedure
The proposed test procedure was based on the Society of Automotive
Engineer's (SAE) Recommended Practice J1203, Light Transmittance of
Automotive Windshield Safety Glazing Materials and the current Test No.
2 in ANSI Z26. However, the agency simplified the test by eliminating
the need to consider the seating reference point when determining the
maximum rake angle.
2. Light Transmittance Levels
Since the proposed new test procedure had the effect of making the
existing transmittance requirements more stringent, NHTSA proposed to
reduce the required light transmittance levels of the windshield to 60
percent. This level is close to the current level of line-of-sight
transmittance for most vehicle windshields as measured by the proposed
procedure (i.e., on average, the transmittance levels would not have
changed from the status quo). Therefore, the proposed reduction in
light transmittance presented no additional safety concern. All but two
currently produced vehicles would have passed the proposed test. NHTSA
requested comment on whether it should specify a line-of-sight
transmittance level higher than 60 percent because a research study
indicated that permitting transmittance as low as 60 percent might
present difficulties for spectacle-wearing drivers and because the
European Economic Community was considering proposing a 65 percent
level.
NHTSA proposed to require front side windows to have a line-of-
sight light transmittance of not less than 60 percent. All current
vehicle models would have complied with the proposed requirement. NHTSA
chose this level because the agency believes that the light
transmittance level for side vision should be the same as for front
vision. Because front side windows are not raked as much as
windshields, front side windows could have become slightly darker under
the proposed amendment.
NHTSA proposed to require 50 percent minimum line-of-sight light
transmittance for rear windows. NHTSA did not propose the 60 percent
line-of-sight transmittance because (1) the 50 percent level is
adequate for high contrast objects, and low contrast objects are less
important in rear vision than in frontal vision, (2) 50 percent
transmittance would be adequate to preserve the benefits of center high
mounted stop lamps, and (3) 60 percent transmittance would disallow a
number of current vehicle designs, for which no safety problem has been
identified. However, the ``privacy windows'' offered as optional
equipment on some MPV's would not be permitted under the proposed
amendment since they have a line-of-sight light transmittance of 20
percent or less.
NHTSA proposed to require 30 percent minimum line-of-sight light
transmittance for the rear side windows. It chose this level because
(1) all new passenger cars and MVS (except MPVs with optional 'privacy
windows') currently meet these requirements, and (2) rear side windows
are less important for driving visibility than other vehicle windows,
so darker tinting on them might not result in measurable adverse safety
consequences.
NHTSA noted that requiring improved reflectance of interior and
side rear view mirrors in Standard No 111, Rearview mirrors, could
compensate for any potential darkening of the side and rear windows.
The agency requested comment on whether those requirements would be
desirable.
3. Vehicles Covered
NHTSA proposed to apply the requirements consistently to all
passenger cars, light trucks, MPVs, and buses with a GVWR 10,000 pounds
or less. This would have represented an extension of light
transmittance requirements to certain unspecified rear and rear side
windows in light trucks that NHTSA has said in interpretations are not
requisite for driving visibility. NHTSA observed that some of these
passenger vehicles were being sold with glass having very low light
transmittance.
4. Compliance by Multi-stage Manufacturers
Some light trucks are manufactured in more than one stage or
altered after they have been completed and certified by the original
manufacturer. Under 49 CFR Part 567, a final-stage manufacturer must
certify that the completed vehicle complies with all applicable safety
standards and an alterer must certify that the altered vehicle
continues to comply with all applicable safety standards. (Throughout
the rest of this document, the term ``final-stage manufacturer'' is
used to refer to both final-stage manufacturers and alterers.) A
practical impact of extending light transmittance requirements to
certain rear and rear side windows in light trucks would have been to
require final-stage manufacturers to certify compliance with light
transmittance requirements for rear and rear side windows, if such
windows are present in a vehicle, as they now do for front windshields
and front side windows.
NHTSA believed that final-stage manufacturers would generally be
able to certify compliance with the expanded light truck requirements
in Standard No. 205 without conducting compliance testing, because they
could continue to rely on the certification of the prime glazing
manufacturer. The prime glazing manufacturer would certify that its
glazing material would comply with the light transmittance requirements
of the standard if installed in a vehicle at up to a certain rake
angle. A final-stage manufacturer would be able to rely on the
certification so long as it installed
[[Page 37823]]
the glazing at an angle not less than the specified angle.
5. Amendments to the language of FMVSS No. 205
To effectuate these changes, NHTSA proposed adding sections to the
standard describing the test procedure and the transmittance
requirements for the various windows. The NPRM also proposed numerous
changes to the sections specifying where the various items of glazing
described in Z26 can be installed in vehicles. Basically, the changes
would have taken those items of glazing that could be installed in
areas requisite for driving visibility and tested under the current
test procedure of Z26, and restricted them to use in trucks, buses, and
MPVs with greater than 10,000 pounds GVWR. At the same time, the NPRM
proposed to create corresponding new items of glazing (item 2A instead
of item 2, for example) that would have been tested according to the
proposed test procedure and permitted to be installed in passenger cars
and light trucks. NHTSA also proposed to designate a new kind of
bullet-resisting glazing that would have 85 percent of the
transmittance of the permanent vehicle glazing.
III. Comments on the NPRM
The nearly 1,000 comments on the NPRM were predominantly negative.
Over 90 percent of the comments came from automobile window tint film
installers, distributors, and manufacturers, and from consumers,
although most of these were form letters. There were also comments from
law enforcement personnel and organizations, legislators, physicians,
highway safety groups, automobile manufacturers, and members of the
glazing industry. The comments are summarized below, grouped according
to the constituency that they represent.
A. Tint Film Industry
The tint film industry (tinters) of 5,000 businesses employing
20,000 people and represented by the International Window Film
Association (IWFA), opposed the proposal and urged NHTSA to amend the
standard along the lines of their original petition. IWFA's extensive
comment was consistent with, and included nearly every argument made
by, the other members of the industry. It stated that there was no
justification for NHTSA to propose higher levels of light transmittance
than the levels for which they had petitioned. It insisted that the
total transmittance be lowered to 24.5 percent. It also disputed
NHTSA's jurisdiction over their industry, citing the Blue Skies case.
IWFA commented that there was no safety problem with tint film. It
stated that one eighth of all cars have tint film, and many MPV's have
privacy glass, yet these vehicles have demonstrated no safety problem.
It further stated that no data had been submitted to the docket proving
a safety problem, that no tinter was aware of any lawsuits or customer
complaints alleging that tint film was a safety problem, and that
virtually all consumers commented that there was a safety benefit to
the film. In addition, it asserted that most police commenters support
the state tint laws, most of which allow more tinting (usually 35
percent total) than Standard No. 205.
In support of its position, IWFA submitted research studies that it
had commissioned. Its studies concluded that 35 percent tint film does
not affect: (1) The ability of police to see into vehicles at night or
at dusk; (2) driver detection of low contrast targets at night or at
dusk; or (3) older driver performance.
IWFA also criticized the conclusions that the agency drew from the
research cited in the NPRM. It stated that two of the studies were
unrealistic, poor quality, or carelessly designed and conducted. In
IWFA's view, the third study actually supported the use of dark tint
films behind the driver.
IWFA asserted that the regulatory flexibility analysis in the NPRM
grossly undervalues the benefits of tinting because it did not consider
the aggregate benefits of tinting. It especially noted the medical
benefits of protection against harmful radiation, and the reduction of
solar load with consequent reduction in fuel consumption and CFC
emissions.
IWFA also stated that NHTSA underestimates the economic impact of
the rule on the tinting industry. According to an IWFA survey, 77
percent of all tinters, which are predominantly small businesses,
stated that they would be put out of business by NHTSA's proposed rule.
IWFA stated that NHTSA, in performing its cost-benefit analysis,
should consider that different areas of the country (e.g., the Sunbelt
versus the Northeast) derive different levels of benefit from tinting.
It stated that, for this reason, a uniform national standard for window
tint is inappropriate and that regulation should be left to vary among
the States.
B. Medical Commenters
The medical commenters were divided on the issue of tinting. Two
optometrists wrote in support of the NPRM. One Arizona doctor supported
the NPRM and does not believe that ultraviolet (UV) radiation is a
significant issue. However, two other doctors commented that they
prescribe tint film for protection from UV radiation. A medical
researcher offered an extensive comment on the need for tint film,
warned of skin conditions and drug sensitivities to even visible light,
and concluded that a thriving tint film industry was necessary for
patients.
C. Safety Groups
Advocates for Highway and Auto Safety (Advocates) opposed the NPRM
because that group believed it would unnecessarily lower windshield and
front side window performance. It also stated that it believed that the
benefits of international harmonization are diluted by unacceptable
light transmittance of the rear and rear side windows. Advocates did
not express a strong opinion on the change in the test procedure to
measure transmittance at the installed angle.
The Insurance Institute for Highway Safety (IIHS) supported the
proposed transmittance requirements for the windshield and front side
windows, and generally supported the proposed transmittance measurement
procedure. However, it opposed the lower transmittance requirements for
the rear and rear side windows. In support of its position, IIHS cited
research that it sponsored on the results of reduced transmittance on
rearward visibility. The study concluded that older drivers would fail
to see low contrast pedestrians up to 83 percent of the time through
glazing tinted to 22 percent transmittance. It concluded that
transmittance levels below 53 percent (measured perpendicular to the
glass) would dangerously reduce nighttime visibility.
D. Law Enforcement Community
The law enforcement community was divided over the issue of
tinting, but was generally opposed to the 30 percent transmittance
requirements for the rear side windows due to security concerns.
Fourteen individual officers wrote to say that they support and use
tint film. Another 232 officers opposed the NPRM because of concerns
about visibility through the darker rear side windows.
Forty-four police departments and State motor vehicle
administrations commented on the proposal. Five supported the NPRM.
Thirty-three opposed the NPRM because of the darker rear side windows.
Six opposed it because it does not allow tinting as dark as that
permitted by the state. Fifteen were opposed because they did
[[Page 37824]]
not like the new measurement procedure. Thirteen favored consistent
rules for cars and vans. Some of the State agencies believe that the
current rule allows States to set transmittance levels, and that the
NPRM would preempt State laws for the first time.
Police in some States ran tests of visibility of the interior of
the vehicle to a person standing outside the vehicle and looking in
through glazing with different levels of transmittance. Virginia and
Maine found 28 percent transmittance to provide unsatisfactory
visibility. New York found 39.5 percent unsatisfactory. Maine and New
York found 40 percent and 58 percent levels of transmittance,
respectively, to be satisfactory.
E. Manufacturers of Motor Vehicles
Most of the manufacturer commenters urged that the current standard
be maintained until further research indicates a safety need for a
change. Ford, GM, Chrysler, Toyota, and the Motor Vehicle Manufacturers
Association (now known as the American Automobile Manufacturers
Association (AAMA)) all asserted that NHTSA had demonstrated no safety
need for the proposal. They cited NHTSA's own conclusion in its Report
to Congress that the current light transmittance requirements do not
pose an unreasonable risk of crash occurrence. They urged NHTSA to
conduct research to quantitatively relate driver visibility needs to
crash occurrence before regulating in this area. GM stated that NHTSA
should not single out lighting in its analysis from other
interdependent factors, such as glare and driver fatigue, relating to
crash avoidance.
The foreign vehicle manufacturers generally supported the proposed
measurement procedure. Mercedes Benz gave unqualified support to the
measurement procedure. Toyota and Suzuki both agreed in principle with
the line-of-sight measurement method. However, Suzuki opposed the
variability that the new procedure would introduce and instead
recommended retaining the existing test and adding a mathematical
formula to adjust the results to take the rake angle into account.
Volkswagen stated that the procedure was incomplete because the optical
systems, procedures, and definitions for certain terms were
inadequately specified. Volkswagen and Fiat both recommended the
adoption of the European test procedure.
The domestic manufacturers all opposed the new measurement
procedure. Chrysler stated that NHTSA's method of defining the
installation angle was not objective because sometimes the test
installation angle might be higher than the actual angle. Ford and the
AAMA asserted that simply changing window trim components on a single
vehicle model could alter the test installation angle, and therefore
the measured transmittance, even though these changes would not affect
the real world installation angle and line-of-sight transmittance. Some
of these commenters stated that NHTSA was wrong to base the procedure
partly on SAE Recommended Practice J1203, because the development of
reflective coated glazing materials had caused the industry to reassess
that practice's adequacy and, after the NPRM was published, to take
steps to withdraw it.
Ford, GM, and Chrysler also claimed that NHTSA had underestimated
the costs of complying with the new test procedure. Ford reported a
round-robin test among the manufacturers to support its claim that
accurate transmittance measurements could not be made through glazing
at windshield rake angles, and concluded that compliance costs would be
higher, if indeed the test procedure were repeatable enough to allow
certification at all.
Some commenters stated that the procedure was impracticable because
the instrumentation necessary to implement it does not exist. Chrysler
stated that there are no instruments designed to measure transmittance
repeatable with the test specimen at an angle, that it is impractical
to try to eliminate all extraneous light, and that existing test
equipment would be prone to variability. Hitachi Instruments also
commented that there is no commercially available equipment, but said
that NHTSA's procedure could be implemented using spectrophotometers,
if certain changes were made as Hitachi recommended.
The foreign automobile manufacturers had mixed reactions to the
various proposed transmittance levels. Mercedes Benz gave unqualified
support to all the proposed transmittance levels. Volkswagen agreed
with all the proposed levels except for the 50 percent for the rear
window, which it urged be lowered to 40 percent. Toyota opposed all the
proposed levels except the 30 percent for the rear side window, stating
that NHTSA's report shows that 50 vehicle models, and many of Toyota's
current models, would not be in compliance due to their rake angle or
the fact that they employ solar energy reflecting glass. Suzuki and
Fiat supported the 60 percent level but opposed any higher level.
The domestic vehicle manufacturers all opposed the light
transmittance requirements on safety grounds primarily for the reason
given above, i.e., that NHTSA had no research proving that there was a
safety problem or that it had chosen the correct transmittance levels
in the various windows. Ford stated that visibility decreases at a
constant rate as light transmittance decreases--therefore, without a
break in the curves that could be used as a critical value, the
specification of any particular value was arbitrary.
Ford criticized the research studies that the agency relied on to
select the proposed transmittance levels. It stated that the NHTSA
research was unrealistic because it used passenger cars in a laboratory
environment rather than vehicles typically equipped with privacy glass.
Ford cited a GM study indicating that drivers of vehicles equipped with
privacy glass would likely compensate for decreased visibility, as a
result of the higher seating positions and belt lines, by using the
vehicle's larger side view mirrors. Ford also submitted an analysis of
National Automotive Sampling System (NASS) data that it claimed showed
that privacy glass equipped vans have a better safety record than
station wagons.
The commenters also cited the loss of benefits of preventing
excessive amounts of glare, visible light, and dangerous UV radiation.
GM suggested that the loss of daytime safety that would result from
disallowing darker tinting might more than offset any increase in
nighttime safety.
GM, Ford, and Chrysler all asserted that the proposed transmittance
requirements would also increase costs. They all commented that less-
tinted glazing would increase the solar load and necessitate a redesign
of the air conditioning systems to achieve higher capacity, possibly
resulting in a loss of fuel economy. Ford even suggested that body
redesign might be necessary to provide for larger grills. GM stated
that the additional radiation and heat reaching the inside of the
vehicle would cause more rapid degradation of the instrument panel,
seats, and other interior materials. GM submitted computer modeling
studies of interior vehicle temperatures with different glazing
materials. GM concluded that it would have to find or develop new,
probably more expensive materials and possibly even redesign instrument
panels. Also, it asserted that recently introduced heat absorbing and
reflective coated windshields would not be able to be used with
installation angles greater than 60 degrees.
[[Page 37825]]
Nearly all vehicle manufacturers were opposed to the elimination of
privacy glass on the rear and rear side windows of light trucks. They
also pointed out that there had been no customer complaints about these
products, despite heavy market penetration (50-80 percent) on vehicles
where it was offered as an option. GM stated that, given the safety-
consciousness of its consumers, the absence of complaints was, in
itself, an indication that privacy glass presented no safety problem.
Toyota suggested that elimination of privacy glass would result in more
vehicle theft, as the cargo became more visible from the outside. In
addition, several commenters asserted that there are no available
alternative glazing materials that can match current privacy glass in
solar rejection and appearance, and that development of these glazing
materials would take at least five years.
Some commenters stated that NHTSA should clarify what is meant by
the term ``requisite for driving visibility.'' Stating that the
proposal would divorce the new transmittance requirements from the
portion of Z26 that refers to the term, Mercedes Benz suggested that
NHTSA add a definition for ``shade bands'' and declare them not
requisite for driving visibility. Suzuki requested that a definition of
the phrase be included in the standard.
F. Glazing Manufacturers
PPG Industries (PPG) and Libby Owens Ford (LOF) both emphasized the
significant research and investments they had made in developing solar
and heat reduction glazing. PPG and LOF believe that the proposed
transmittance requirements in the standard would eliminate both the new
glazing and the use of standard products by the industry. LOF opposed
all aspects of the rulemaking, but recommended various lower
transmittance values that would allow the continued use of existing
glass products, in the event that NHTSA planned to implement the
proposal.
PPG also stated that the lead time required to produce new products
that meet the proposed requirements would necessitate the temporary use
of less effective materials. LOF estimated that compliant solar control
glazing would take five years to develop and test.
PPG stated that heat resistant glazing is more effective than NHTSA
assumed in the NPRM, because the heat transfer rate from the glass to
the outside air is higher than the heat transfer rate from the glass to
the vehicle interior. PPG and LOF also asserted, without providing
data, that fuel economy would be reduced by up to 10 percent, or 1.0-
1.5 mpg without solar control glass. These and other commenters stated
that steeply raked windshields have the greatest need for solar
rejection glazing, yet are also the most likely to be restricted in its
use by the proposed transmittance requirements.
The glazing manufacturers asserted that NHTSA overestimated the
relative impact of light transmission on visual acuity. PPG conducted
vision studies at Rensselaer Polytechnic Institute that it said
indicate that other factors, such as age, road condition, and glare
affect visual acuity more than windshield light transmission reduction
(down to 50 percent). At night, with lights shining in the driver's
eyes, the reduced windshield transmittance reduced driver visibility by
less than one percent. LOF submitted a study conducted in cooperation
with GM and Cornell University that suggested that night driving was
actually improved when tinted glass was substituted for clear glass.
Regarding the safety of police, LOF suggested that NHTSA consider the
effect of external reflectivity of the outside surface of the glazing
and include in the standard a maximum exterior reflectance of 25
percent.
Glazing manufacturers also commented that the proposed test
procedure is impractical and unnecessary, and would increase costs. PPG
stated that the test is complex, requires very sophisticated and
expensive instrumentation and computer software, including an optical
alignment system and a double beam ratio recording spectrophotometer.
LOF estimated that this equipment would cost $500,000. In addition, LOF
estimated that its certification costs for the 175 types of its glazing
would rise from $230,000 to $730,000 annually because it would have to
assign different model numbers to the same glass specifying its use in
front side windows, rear side windows, and rear windows.
LOF commented that glazing parts that are manufactured close to the
lower limit of transmission may fail the standard at the assembly site
(presumably because they are installed at a greater rake angle than
anticipated), rather than at the glass manufacturing plant where
remedial actions are possible. LOF suggested that the standard should
permit calculating the angled transmittance values from the normal
transmittance values using a series of curves.
Finally, the agency received a September 1995 report from DRI/
McGraw-Hill, and a similar docket comment from LOF, indicating that
rake angles have reached a practical maximum. The study of glazing
design trends was conducted for Monsanto, a supplier of automobile
glass, and was based on reviews of the technical literature, secure
interviews with industry, OEM, and government sources, and statistics
run on market profile data. The report concluded that further increases
in rake angles would be limited both by laminate-caused distortion and
by viewing glare design considerations to a range of 63 to 66 degrees
of rake. NHTSA believes the actual maximum is slightly higher, because
it knows of one production vehicle with a 68 degree rake angle. If
these conclusions are correct, the recent trend toward increasing rake
angles will abate.
IV. Analysis of Issues
The commenters have suggested a variety of arguments for why NHTSA
should not go forward with its proposal. NHTSA is relying on some of
those arguments in its decision to withdraw the proposal, but not on
others. This section identifies some of those arguments that NHTSA
finds compelling, and some that it does not find compelling. The
following section, Section V, summarizes the main reasons for the
agency's decision.
A. Line-of-Sight Measurement of Glazing Transmittance
NHTSA continues to believe that a line-of-sight measurement
technique would have many advantages. The technique measures the
effective transmittance of the glazing as it is used in the real world.
It would also allow the nearly vertical rear windows in trucks and some
passenger cars to be more heavily tinted than the more slanted glazing
in most car windows without a relative loss of visibility. The current
test procedure, although easy to perform, has the disadvantage of
allowing vehicles with the same glazing to have radically different
effective transmittance values, depending on the rake angle of their
windows.
However, the commenters have raised significant questions about the
practicability of the proposed procedure. NHTSA agrees that the
procedure is more complex. New, expensive equipment would have to be
purchased and, perhaps even in some cases, developed in order to test
the transmittance of glazing at its installed angle. NHTSA believes
that the certification costs would also increase, although probably not
so much as LOF suggests. The transmittance for a particular type of
glazing that is installed at a variety of angles in different vehicles
would, as a practical
[[Page 37826]]
matter, only have to be tested at the maximum angle at which it is
installed. Only in the unlikely event that a vehicle manufacturer
always installed glazing that is tinted to the maximum extent allowed,
given its installation angle, would it become necessary to make glazing
in a large number of shades to match installation angles.
NHTSA does not agree, however, that it is impossible to measure
transmittance at the installation angle. U.S. manufacturers claimed
that, for coated glass, accurate measurements and calculations are
impossible. Regarding Ford's round-robin tests to demonstrate that
measurements could not be made at windshield rake angles, NHTSA
disagrees with Ford's conclusion. The problem in Ford's testing was
that one company was unable to make accurate measurements, apparently
because the required sample size did not fit that company's test
apparatus. The measurement scatter for the other companies (about 2
percent) was no greater for the solar reflective glazing than for clear
laminated glass. There is some instrumental variation inherent in any
measurement.
NHTSA believes that the approach of measuring the transmittance
normal to the glazing and then using a formula to calculate the
theoretical transmittance at the installed angle would be practical.
This is the approach recommended by LOF and the Japanese automobile
manufacturers. The Japanese manufacturers suggested a computational
method that necessitates only laboratory work to convert normal
transmittance measurements at the manufacturing plant to transmittance
values at angles. Adoption of this approach would solve any problems
associated with measuring coated glass at angles.
There would still be increased costs associated with determining
transmittance by calculation. To the extent that manufacturers want to
install the darkest possible glass, there would still be a
multiplication of the different shades of glazing corresponding to the
various installation angles. If this occurred, it would result in
increased inventory costs from having to produce and maintain a supply
of a greater variety of tinted glazing.
B. Proposed Transmittance Values
NHTSA is also withdrawing the portion of the proposal that
specified different light transmittance levels for the various vehicle
windows. There are several reasons for taking this action.
First, the agency wants to obtain more data defining the
relationship between transmittance and safety before setting different
light transmittance levels, especially in light of the absence of
support for the proposed values. Ideally, the additional data would
include statistics concerning the involvement of vehicles with tinted
windows in crashes, but this is problematic, given the existing data
collection mechanisms. The presence or absence of tint film is not
recorded on State crash report forms. In addition, many crashes that
involve backing vehicles go unrecorded because they occur in parking
lots and driveways, areas that the agency's databases do not cover.
NHTSA will consider how to capture these data in the future.
Second, if the manufacturers are not required to account for the
effect of the installed angle of the glass when measuring light
transmittance, promulgating a larger set of specific transmittance
values for glazing would not necessarily result in the desired levels
of line-of-sight transmittance, because of the wide variety of window
rake angles. For example, two vehicle models using the same 50 percent
transmittance glass (measured perpendicular to the window) in the rear
window would have very different actual transmittances if the windows
on one model were significantly more raked than on the other. Setting
60, 50, and 30 percent transmittance values for various windows would
give a false impression of regulatory precision because the variability
in rake angles would generate a much wider range of in-use
transmittance values.
Third, given the decision to withdraw the proposal to specify
testing glazing at its installed angle, there would have been a scope
of notice problem if the agency had adopted the proposed light
transmittance levels. The proposal had two interdependent parts: (1)
The proposed light transmittance levels; and (2) the proposed new test
method. The adoption of the transmittance levels was premised upon
changing the test method from the current procedure of testing at a
right angle to the glazing to a new procedure of testing the glazing at
the same angle at which an occupant would look through the glazing as
it is installed in a vehicle. For any given piece of glazing, testing
it at a right angle yields higher transmittance values than testing it
at an acute angle, i.e., the installed angle. Since the agency is not
adopting the new test method, it can not adopt transmittance levels
premised on adopting that method. Even if the agency had concluded,
based on the comments and other available information, that it were
nevertheless desirable to go ahead and adopt new light transmittance
levels, the proposed levels would have had to be adjusted upward to
offset the effects of retaining the current test method. However,
adjusting the levels upward, and then adopting them, would have been
beyond scope of notice.
Although the agency is withdrawing this proposal, NHTSA wants to
emphasize that it does not accept the proposition advanced by some
commenters that the agency cannot regulate in this area without
numerically linking crash data to specific light transmittance values.
Isolating the contribution of light transmittance from the
contributions of the other interrelated driver, vehicle, highway, and
environmental factors that cause crashes is extremely difficult.
Predicting the effectiveness of countermeasures such as uniform line-
of-sight light transmittance at certain values is even more difficult.
Although NHTSA attempts, within its capabilities, to quantify the
benefits of its actions, it still has a duty to regulate when such
regulations would meet the need for motor vehicle safety, even in areas
with inherent uncertainty. Therefore, especially for the crash
avoidance standards, decisionmaking necessarily rests in part on policy
judgment.
The agency is not basing its decision to withdraw the proposal on
the research data submitted by IWFA regarding the effect of different
levels of light transmittance on object detection. The researchers
employed by IWFA used a simulator-type experiment in an attempt to
demonstrate that glazing with transmittance as low as 17 percent did
not interfere with object detection during left turns, backing, or lane
changing. The value of the simulation is questionable, since the
actions were sequential, and therefore less challenging than an actual
driving experience in which a driver must operate the vehicle controls
at the same time he or she is attempting to look through the glazing
and detect objects outside the vehicle in the driving environment.
Further, the method of characterizing the average contrast of the
targets may be misleading because the targets were not homogeneous in
color or reflectivity (e.g., it is easier to see someone in a dark suit
if he or she is wearing a white hat). NHTSA also does not regard a 22
percent target detection failure rate as good performance.
In fact, most research indicates that light transmittance and
safety are related. In 10 of the 15 investigations of target detection
with varying light transmittance, there were reductions in the
subjects' abilities to identify and detect targets corresponding with
[[Page 37827]]
reductions in transmittance. The agency believes that the few
investigations in which there was not any significant relationship used
inappropriate experimental performance criteria, target contrast,
illumination, and task difficulty. Some did not even use glazing with
transmittances of less than 70 percent. NHTSA concludes that the most
credible studies confirm the common-sense relationship between light
transmittance and target identification.
In response to those commenters that believed the NPRM would for
the first time preempt States from setting their own transmittance
requirements, NHTSA notes this would not be the case. Federal law
already preempts States from setting any different level of
transmittance for regulated windows on new vehicles at the time of
sale. Federal law also preempts States from allowing businesses to make
inoperative the transmittance levels on regulated windows of used
vehicles. However, States are free to set and enforce lower minimum
transmittance levels on regulated windows for vehicles to be licensed
in or used in the State.
Similarly, States are free to set and enforce transmittance levels
for windows not regulated under the Federal standard (e.g., the rear
and rear side windows of light trucks). The States are free to prohibit
dark windows in these vehicles if they believe it is necessary for the
safety of police officers.
V. Agency Decision
After reviewing the available information, NHTSA has decided to
withdraw the proposal regarding the light transmittance requirements of
Standard No. 205, for the following reasons:
(1) While the proposal to measure light transmittance at the
installed angle has theoretical merit, the proposed requirements would
add costs for manufacturers, in the form of increased testing,
certification, and inventory costs, which would be passed on to
consumers without, as noted below, providing any assurance of
commensurate additional benefits.
(2) There is limited prospect of commensurate increases in
visibility and safety. The agency believes that, barring unforeseen
advances in glass properties, windshield rake angles have now reached a
practical limit of about 66 to 68 degrees due to the need to avoid
visual distortion. If this is true, the recent trend toward greater
rake angles will not continue. Thus, one of the agency's concerns when
issuing the NPRM is now moot. At windshield rake angles of 66 to 68
degrees, there would be little practical improvement in windshield
visibility between the proposed regulation and the current regulation
to offset the increased costs.
(3) The proposed amendment would have had the practical effect of
limiting solar reflective windshields to a rake angle of about 63
degrees. The difference in transmittance between the same windshield at
rake angles of 63 degrees and 66 degrees is slight and not commensurate
to the cost of limiting vehicle design or the changes that might be
forced on glass technology.
The agency intends to monitor developments in this area. Should the
factors limiting rake angle be overcome in the future and more extreme
rake angles become a reality, the agency may revisit the issue.
(4) NHTSA finds persuasive the industry comments that the proposal
would make solar control glazing less feasible and more costly for
windshields. The windshield is the principal point of entry of solar
heat into the interior of most vehicles. Increased rake angles
exacerbate solar heating by presenting a more favorable angle for solar
radiation and a greater uninsulated surface area. A type of windshield
glazing which reflects infrared solar radiation, while retaining the 70
percent perpendicular visible light transmittance required by the
present regulation, has been developed for vehicles with high rake
angles. Since the proposal would have only affected vehicles with the
highest rake angles (over 63 degrees), a possible unintended
consequence would have been to bar the use of the most effective solar
control windshield glazing on the vehicles with the greatest need of
it. Since the agency no longer foresees a continuing trend toward
greater windshield rake angles, it is not inclined to prohibit the use
of the best currently available solar control windshield glazing for
the sake of effective light transmittance differences that are very
small at the rake angles that are possible, given the limits on rake
angles imposed by visual distortion.
(5) NHTSA wishes to better define the relationship between light
transmittance and highway safety before requiring differing
transmittance values for different vehicle windows.
(6) Without line-of-sight measurements, setting specific
transmittance values would not result in consistent actual light
transmittance. The wide range of window rake angles would result in
different line-of-sight transmittance values, even when the drivers of
vehicles with different rake angles are looking through identical
glazing. Therefore, promulgating graduated transmittance values would
give a false sense of precision.
(7) The decision to withdraw the proposal to establish light
transmittance levels for additional classes of motor vehicles was also
based on the fact that the proposed transmittance levels were premised
upon adopting the proposed new test method. Since the agency is not
adopting the new method, it can not adopt transmittance levels selected
on the basis of that method.
VI. ``Reissuance'' of Standard No. 205
The light transmittance requirements for Standard No. 205 were
originally adopted pursuant to the first sentence of former section
103(h) of the National Traffic and Motor Vehicle Safety Act (Safety
Act), 15 U.S.C. Sec. 1392(h), as the ``initial'' standard based on an
``existing'' standard (i.e., ANSI Z26). The second sentence of that
section provided that ``new and revised standards'' should be issued
``on or before January 31, 1968.''
Section 103(h) was repealed in conjunction with the 1994
codification of the Safety Act into 49 U.S.C. Chapter 301. The House
Judiciary Committee Report accompanying that codification states that
the section was repealed because it had already been ``executed.'' This
supports the agency's view that section 103(h) did not impose a
continuing duty upon the agency to reissue each of the initial
standards that had been based on safety standards that existed prior to
enactment of the Safety Act. Nevertheless, to the extent that former
section 103(h) could have been construed as requiring a reexamination
and reissuance of such standards, the present rulemaking proceeding
constitutes such a reexamination and reissuance of the current
standard.
This reissuance does not affect the requirements of the standard,
but simply reaffirms and republishes the requirements as they presently
exist in 49 CFR part 571.205. For this reason, no regulatory analyses
have been conducted.
Issued: July 8, 1998.
L. Robert Shelton,
Associate Administrator for Safety Performance Standards.
[FR Doc. 98-18704 Filed 7-13-98; 8:45 am]
BILLING CODE 4910-59-P
