[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]


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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.

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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:
    <bullet> 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.
    <bullet> 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.
    <bullet> 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.
    <bullet> 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