Federal Motor Vehicle Safety Standards; Glazing Materials

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:

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