specifications. Third, the final rule's extensive modifications to the
proposed track test, resulting in a streamlined set of test scenarios,
should also help address concerns about heavy-vehicle testing.\78\
---------------------------------------------------------------------------

    \78\ We also note that NHTSA was unable to perform testing on
heavy-duty vehicles because it was not aware of any such vehicles
that are ADB-equipped. In any case, for the reasons given above, we
do not believe that it is necessary to test heavy-duty vehicles
prior to adopting this rule.
---------------------------------------------------------------------------

    Finally, while the requirements and test procedures in the final
rule are an increase in stringency from the longstanding requirements
for semiautomatic beam switching devices, this final rule is
appropriate because ADB systems are capable of providing an enhanced
beam that is brighter than the lower beam, which presents an increased
risk for glare if the system is not designed appropriately.
2. Test Fixtures vs. Stimulus Vehicles
    NHTSA identified two main alternatives to the proposed broad range
of eligible stimulus vehicles that would be used to elicit an ADB
system response. First, the agency considered specifying a small set of
specifically-identified stimulus vehicles, but tentatively decided that
a broad range of potential stimulus vehicles was necessary to ensure
that an ADB system can recognize multiple headlamp/taillamp
configurations on vehicles of different sizes and shapes.
    Second, NHTSA considered specifying test fixtures, including those
specified in SAE J3069.\79\ The NPRM noted SAE's rationale that
fixtures represent a worst-case scenario because some cameras use
movement to identify objects as vehicles. It also noted SAE's
explanation that the fixture lamps would represent a ``reasonable worst
case for intensity and location and should promote test
repeatability.'' \80\ NHTSA also noted that test fixtures could be
easier to use than actual vehicles.
---------------------------------------------------------------------------

    \79\ See NPRM at p. 51782-51783.
    \80\ SAE J3069, p. 3.
---------------------------------------------------------------------------

    However, the proposal identified several potential concerns with
test fixtures. The major concern was the lack of realism, so that
fixtures might not indicate whether the ADB system would recognize
actual vehicles and instead could permit ADB systems to be tuned to
detect fixtures. Another concern related to possible difficulties in
tuning out non-vehicle objects. Also of concern was the possibility
that the fixture characteristics might not represent a worst case.
    The NPRM therefore proposed a large set of eligible stimulus
vehicles. The agency tentatively concluded that it would be practicable
for manufacturers to design ADB systems to recognize and

shade any vehicle satisfying the proposed selection criteria. NHTSA
noted that the lighting configurations an ADB system would have to
recognize would not be unreasonably large, as front and rear lighting
designs are limited by the requirements of FMVSS No. 108 and the
realities of vehicle design. NHTSA also reasoned that there is a
limited, and not exceptionally large, number of makes and models of new
vehicles offered for sale in the United States every year
(approximately 420), and that the set of eligible stimulus vehicles
would be further limited by the proposed vehicle height constraint.
Comments
    Vehicle and equipment manufacturers opposed the use of stimulus
vehicles and commented that NHTSA should instead follow SAE J3069 and
use test fixtures. These commenters identified a variety of specific
concerns with stimulus vehicles.
    Several commenters (Mobileye, EMA, Volkswagen, SMMT, Ford, Toyota,
SAE, the Alliance, Global, and Honda) contended that the proposed
stimulus vehicle specifications would result in an impracticably large
set of potential vehicles. For example, SAE and the Alliance commented
that the NPRM specified an unmanageable and exceptionally large number
of potential stimulus vehicles, exacerbated by the fact that many
vehicles have multiple headlamp and/or taillamp trim levels, and that
the proposal does not account for motorcycles or heavy-duty vehicles.
They estimated that this could result in a set of up to 1,000 eligible
stimulus vehicles. The Alliance also contended that it would be
impossible for a manufacturer to choose a worst-case scenario and
guarantee that testing with the other thousands of vehicle choices
would exhibit reproducible results for the multitude of requirements.
MEMA, Volkswagen, and the Alliance commented that the proposal would
cause manufacturers to incur costs from repeated testing as the
stimulus vehicles need to be refreshed every year. Volkswagen also
commented that obtaining stimulus vehicles would be especially
burdensome for foreign original equipment manufacturers (OEMs) and test
facilities.
    Mobileye, SAE, Honda, and Ford commented that an FMVSS requiring a
manufacturer certification to account for the various configurations
and performance of thousands of vehicles in the market would be
unreasonable and unprecedented, as opposed to other FMVSS which
simulate real-world conditions with standardized test apparatus. As an
example, SAE, Ford, and Honda pointed to FMVSS No. 208, which uses a
fixed barrier to simulate a stimulus vehicle crashing head on into the
test vehicle within one specified range of speeds and does not require
selecting actual vehicles from a large population available in the
market to conduct this testing. Honda also pointed to FMVSS No. 214
(side impact) and FMVSS No. 301 (rear impact), and various New Car
Assessment Program (NCAP) test procedures that standardize the device
used to assess the crashworthiness of the test vehicle. SAE and Honda
contended that this approach allows the test to be practicable and
objective, and SAE suggested such an approach would be sufficiently
realistic because, as the NPRM noted, the lighting configurations an
ADB system would have to recognize are limited by the requirements of
FMVSS No. 108 and realities of vehicle design.
    Commenters also raised concerns related to vehicle production
cycles. SAE and Ford commented that the cycle plans of any given
vehicle design can last many years, with those designs solidified many
months prior to production, making it impossible for manufacturers to
account for other manufacturers' vehicles in any manageable timeframe.
A manufacturer would not be aware of which vehicles may pose compliance
challenges for its ADB system prior to these vehicles being sold to the
public, especially considering the extremely conservative and
challenging requirements associated with the NPRM. Honda made similar
comments.
    Mobileye commented that the proposal would lead OEMs to over-tune
the ADB system in order to ensure compliance, resulting in non-optimal
and overly sensitive system behavior and diminished safety benefits.
    Several commenters (Global, Mobileye, Valeo, the Alliance, MEMA,
and Volkswagen) raised concerns regarding the repeatability and/or
reproducibility of compliance test results. SAE, the Alliance, SMMT,
and Honda commented that the proposal was not objective.
    A few commenters did support using stimulus vehicles. Consumer
Reports supported a broad range of stimulus vehicles as reasonable to
adequately ensure ADB systems detect, identify, and shade vehicles of
different size, shape, and lighting configurations; however, it also
urged that testing be practical and efficient. Intertek commented that
a simple static test fixture may not be sufficient, and that using any
make or model within defined physical constraints is preferable to
adding an appendix with a list of eligible test vehicles. AAA commented
that no certified motor vehicle should be excluded from use as a
stimulus vehicle, and that the proposed limitation to the past five
model years together with the vehicle height constraints were practical
and acceptable.
    Several commenters, while not supporting the use of actual
vehicles, commented that if NHTSA were to use actual vehicles, it
should further limit the set of eligible stimulus vehicles. SL
Corporation (SL) commented that detailed criteria for stimulus vehicles
(such as light source, luminous intensity of the stimulus vehicle's
headlamp and rear lamp), specified by vehicle type, is needed. Global
commented about a need for consistency in any testing, further arguing
that the rule could bookend the vehicle population's performance (i.e.,
lowest/highest, narrowest/widest) to constrain the massive number of
stimulus vehicles. Toyota suggested that NHTSA limit the number of
stimulus vehicles to a practical and manageable list by only using the
top three U.S. selling vehicle models for each of the vehicle types
identified in Table XXI of the NPRM in the fifth model year prior to
the model year of the certified vehicle. Honda stated that if NHTSA
does not adopt test fixtures, it should test with a single stimulus
vehicle chosen by the manufacturer. Valeo suggested specifying a
standard stimulus vehicle. Mobileye suggested modifying SAE J3069 by
defining the use of a standardized dummy stimulus vehicle with lamps
representative of those approved by FMVSS No. 108 instead of the static
fixtures specified in SAE J3069. Mobileye also recommended
complementing the (modified) SAE test with a requirement for an
additional test drive by a test engineer to ensure stable detection and
reaction to vehicles of different makes and models in additional real-
world scenarios not specified in the track test.
Agency Response
    After evaluating the comments and considering the requirements of
the Safety Act and the National Technology Transfer and Advancement Act
(NTTAA),\81\ NHTSA has decided to specify test fixtures instead of
stimulus vehicles. The NTTAA directs agencies to use voluntary
consensus standards unless, among other things, doing so would be
inconsistent with applicable

law. We believe the test fixtures specified in the final rule are
consonant with both the Safety Act and the NTTAA.\82\ In particular, we
believe the test fixtures both meet the need for safety and better
align with SAE J3069 and other countries' standards.
---------------------------------------------------------------------------

    \81\ National Technology Transfer and Advancement Act of 1995,
Public Law 104-113, 110 Stat. 775 (1996). See Section X, Rulemaking
Analyses and Notices.
    \82\ We also note that the final rule does not adopt Mobileye's
suggestion to supplement the track test with an evaluative drive by
a test engineer, because such a requirement would not satisfy the
Safety Act requirement of objectivity.
---------------------------------------------------------------------------

    Most importantly, we concluded that the test fixtures specified in
the final rule meet the need for safety. There are two main reasons for
this. First, in this case the need for safety requires us to balance
visibility and glare prevention. As some commenters pointed out, a too-
demanding track test to evaluate glare, including a large set of
eligible stimulus vehicles, could lead manufacturers to tune the system
to provide sub-optimal forward illumination. Second, we concluded that
using real vehicles would generally not challenge ADB systems any more
robustly than properly-specified fixtures. In the NPRM we expressed the
concern that insufficiently realistic test fixtures could lead to ADB
systems with performance tuned to the fixtures, not to real vehicles,
resulting in a test that does not sufficiently replicate real-world
performance. To address this concern, NHTSA developed test fixtures
fitted with original manufacturer replacement equipment vehicle
headlamps and taillamps, instead of the lamps specified in SAE J3069
that are intended to simulate vehicle lighting. (See Section VIII.C.6
for a discussion of the final fixture specifications.) NHTSA then
tested whether an ADB system performed differently with these fixtures
than with an actual vehicle. As explained below, this testing showed
that the ADB system detected and responded to the finalized test
fixtures in generally the same way it did to an actual vehicle.
    NHTSA's recent research compared ADB performance when tested with
the finalized stimulus fixtures versus a stationary stimulus (i.e.,
actual) vehicle. For the most part, differences in performance were not
observed. For example, in straight oncoming and preceding test
scenarios, the ADB system recognized both the stimulus vehicle and test
fixture before either stimulus entered the measurement range. See
Figures 4 and 5.
[GRAPHIC] [TIFF OMITTED] TR22FE22.004

[GRAPHIC] [TIFF OMITTED] TR22FE22.005

    One exception to this was observed for the smallest-radius left
curve (oncoming) at the highest speed. In this case, the ADB system
performed better (recognized and adjusted sooner) when exposed to the
test fixture. For the fixture, the test vehicle adjusted its light
output at around 44 m and did not exceed the glare limits. For the real
vehicle, it reacted at 39 m, resulting in a glare exceedance. This
suggests that this ADB system likely relies on light source detection
rather than using supplemental systems such as radar or LIDAR to detect
a vehicle structure. Although we did not systematically test this
hypothesis, we suspect that the performance differences observed in
this case are caused by small differences in headlamp mounting heights
between the fixture and the real vehicle. See Figure 6. The agency did
not observe any situations in which the full vehicle was recognized,
but the test fixture was not.

[GRAPHIC] [TIFF OMITTED] TR22FE22.006

    The test fixtures specified in the final rule more closely align
with SAE J3069 and better harmonize with other countries' standards
than the proposed broad range of eligible stimulus vehicles. This
should help facilitate deployment of ADB systems in the United States
because manufacturers are already familiar with SAE J3069 and because
it harmonizes with the Canadian regulations, which permit ADB systems
designed to meet either ECE R123 or SAE J3069. This approach also
results in a more manageable set of test scenarios and stimulus
vehicles to which manufacturers must certify,\83\ which will also
result in a less complex and costly test. Test fixtures will reduce the
test burden by establishing a consistent stimulus for testing, reducing
the cost of acquiring and maintaining the test stimulus, reducing the
test time, and more closely harmonizing with SAE J3069. NHTSA's testing
showed that fixtures simplified the coordination of each test run. A
single test driver was required to drive the test vehicle as opposed to
two drivers required for tests involving dynamic stimulus vehicles.
Additionally, no start and stop coordination was needed between the two
drivers. The use of fixtures also facilitates set-up for different
scenarios.\84\
---------------------------------------------------------------------------

    \83\ Specific to this rulemaking, NHTSA has concluded that using
test fixtures better balances the safety needs of visibility and
glare prevention, and is more practicable and appropriate, than
using a broad range of potential stimulus vehicles. We are not
implying that a large set of potential stimulus vehicles is
necessarily impracticable for an FMVSS. We also note that we do not
agree with the commenters who claimed that the proposal raised
issues with respect to objectivity, repeatability, or
reproducibility.
    \84\ NHTSA developed a single test fixture that was capable of
mounting both the motorcycle and the car/truck vehicle lamps; the
various lamps could be switched between test runs of different
scenarios.
---------------------------------------------------------------------------

3. Justification for Testing on Curves and General Approach for
Scenario Selection
    In addition to testing ADB performance in a straight-path scenario,
the NPRM proposed testing ADB systems on curved-path scenarios (both
left and right curves) with a variety of radii of curvature. The agency
proposed testing on a ``small'' curve with radii of curvature from 98
m-116 m (320-380 ft); a ``medium'' curve with radii of curvature of 223
m-241 m (730-790 ft); and a large curve, 335 m-396 m (1100-1300 ft).
The NPRM explained that the small curve was chosen because it
corresponded (approximately) to the shortest radii of curvature
appropriate for a vehicle traveling 25-35 mph, approximately the
minimum speed for which we proposed to allow ADB activation. The medium
curve corresponded to the shortest radii of curvature appropriate for
the higher ADB minimum activation speeds of some of the ADB-equipped
vehicles NHTSA tested. Finally, the large curve was intended to
correspond to a curve appropriate for vehicles traveling at higher
speeds, to test ADB performance on curves at higher speeds. Values for
speed and radius of curvature were selected to be consistent with the
simplified curve formula.\85\
---------------------------------------------------------------------------

    \85\ This is a standard formula used in road design that
specifies the relationship between vehicle speed and the radius of
curvature. See infra n.142 and accompanying text.
---------------------------------------------------------------------------

    The NPRM recognized that curves might present engineering
challenges for ADB systems. For example, on a curve an oncoming vehicle
enters the ADB system's field of view (FOV) from the edge; in a tight
curve, an oncoming vehicle will enter the field of view at a closer
distance than in a larger-radius curve. Performing adequately on large-
radius curves at relatively high speeds consequently presents a
slightly different engineering challenge than performance on tight
curves at lower speeds.
Comments
    Consumer Reports supported testing using curved path scenarios of
various curvatures. Intertek supported a more rigorous dynamic roadway
test than specified in SAE J3069 (which specifies straight test drive
paths) because the SAE J3069 approach may not be sufficient to validate
the performance of the ADB sensor over the range of situations that it
will normally encounter.

    On the other hand, several commenters opposed or raised issues with
testing on actual curves. SAE commented that NHTSA should follow SAE
J3069 and simulate curves using a straight path and varying the
placement of the test fixtures. SAE contended that curves are not
necessary because continuous tracking of the angular location of the
test fixture in straight scenarios is required, and that removing
curves would greatly reduce the testing burden. SAE noted that it
considered including curves in SAE J3069 but concluded that attempting
to capture hundreds of potential road geometries would make the test
excessively burdensome because ADB systems would function similarly
over many of these geometries and including them all would provide no
added value. SAE further determined that testing on a straight path
with one lane to the right and more than one lane to the left of the
ADB-equipped vehicle would capture the conditions necessary to
determine whether an ADB system functions appropriately and ensures an
adequate response to a wide variety of road geometries, while allowing
the test method to be simple enough to be objective and repeatable. For
example, SAE J3069 requires that in a straight-line encounter, an ADB
system must continuously track the angular location of an opposing
vehicle fixture as that angular position becomes increasingly further
from the center of the camera's field of view with decreasing distance
to the opposing vehicle. SAE commented that such an approach allows
evaluation of vehicles encountered on curves to be captured without
using actual curves.
    SAE, ALNA, Toyota, and the Alliance stated that the proposal would
require ADB systems to produce less glare than current FMVSS No. 108-
compliant lower beams, and that this issue was particularly acute on
curves. They argued that the proposed approach would reduce lower beam
visibility and negatively impact safety. SAE provided analyses and
graphs based on IIHS data on lower beam performance on different road
geometries, from straight roads to left and right curves of various
radii. Stanley and Intertek also asserted that the final rule should
account for the fact that current lower beams would not comply with the
glare limits on right curves.\86\
---------------------------------------------------------------------------

    \86\ The commenters' data and arguments on these points are
discussed in more detail in the sections below discussing each of
the test scenarios in the final rule.
---------------------------------------------------------------------------

Agency Response
    The final rule does not adopt some commenters' recommendation to
forgo actual curved-path scenarios, but it does reduce the measurement
distances in many of the test scenarios for which curves are specified.
    The agency is not persuaded that the SAE J3069 approach of
simulating curves by varying fixture placement relative to a test
vehicle's straight path adequately replicates curves. Two features of
the SAE test are intended to replicate what the system would encounter
in an actual curve. First, the fixtures are placed to the side of the
test vehicle's path. Second, the sudden appearance scenario is intended
to roughly replicate a curve in that the fixture's stimulus lamps
become visible at a close distance, which would happen on a relatively
tight curve. (The sudden appearance scenario is also intended to
exercise the ability of the ADB system to react to real world
situations such as another road user turning on their lights, turning
onto the road, or cresting a hill at distances as close as 100 m.) This
approach, however, does not accurately replicate real curves in at
least two respects.
    One is the trajectory of the fixture as it is tracked by the ADB
system (see Figure 7). An approaching vehicle on an actual curve enters
the ADB system's field of view from the edge, at a relatively far
distance; moves towards the center of the field of view as the distance
to the fixture closes; and then moves out towards the edge of the field
of view at a close distance. The trajectory is different, however, when
attempting to replicate a curve using a straight path and fixtures
placed out to the side. There, the fixture is first detected by the ADB
system near the center of the camera's field of view at a far distance,
and then moves out towards the edge of the field of view at closer
distances.
    For example, on an actual left curve with a radius of 230 m, the
fixture enters the FOV at the edge (25L) at a relatively far distance
(191 m) and moves towards the center of the FOV until around 35 m at
which point it moves out towards the edge of the FOV again (see Figure
7). In comparison, in the SAE test run, at 155 meters (the start of the
SAE test), Fixture 1 is near the center of the FOV at approximately 2.5
degrees left, and as the test vehicle approaches the fixture the
fixture moves out to the edge of the field of view.
    As another example, this time on a right curve with a radius of 230
m, the fixture enters the FOV at the right edge of the field of view
(25R) at about 205 m and moves towards and then across the center of
the FOV. In comparison, in the SAE test, at 155 meters (the start of
the SAE test), Fixture 3 is near the center of the FOV (at about 3
degrees right), and as the test vehicle approaches the fixture the
fixture trajectory moves out to the right edge of the field of view.
The SAE test evaluates rather large angles to the right of the beam
pattern, almost entirely to the right of where the NHTSA test method
examines the beam pattern performance. The agency believes this to be
unusual in reality, particularly for oncoming encounters.
    Because the SAE test does not accurately replicate the fixture
trajectory, it does not test how the system will need to actually
function. For example, one way to ``optimize'' optical recognition is
to focus on where an object is most likely to appear. The speed and
accuracy of image recognition software can be increased without
increasing computing power if systems are trained to look in smaller
portions of an image for key elements, as opposed to looking at the
entire image continuously. Including test scenarios with actual curves
will discourage manufacturers from taking ``shortcuts'' and designing
ADB systems that do not react until the stimulus vehicle enters narrow
angles within the camera's FOV.
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[GRAPHIC] [TIFF OMITTED] TR22FE22.007

    Second, the SAE approach does not accurately replicate real curves
with respect to the speed at which the fixture traces its trajectory.
On an actual curve, the fixture travels horizontally across the FOV
relatively quickly at longer distances than on a simulated curve. For
instance, a left curve requires the headlamp to start shading on the
left side of the pattern, quickly move to the right; briefly hold the
shade near the middle; and very quickly move the shade back to the far
left. A simulated curve, on the other hand, simply necessitates that
the system starts shading the middle of the pattern; hold nearly that
same angle; and then quickly move the shade either left or right at
closer distances. Including actual curved-path scenarios will
discourage manufacturers from very accurately following the straight
path pattern but less accurately following the paths required for real-
world curves; it should therefore result in better real-world
performance than would the SAE J3069 fixture placements.
    NHTSA's recent testing confirmed that the SAE scenarios do not
accurately model how an ADB system will perform on an actual curve. For
example, the agency tested ADB system performance on an 85 m left curve
as well as the most closely analogous SAE scenario, with the fixture
place in Fixture Position 1. (Fixture Position 1 is the closest
analogue to this scenario because it is the leftmost fixture position
in the SAE test.) See Figure 8. On the actual curve, the system did not
recognize and adjust to the fixture until 45 m. On the most closely
analogous SAE scenario (Fixture Position 1), the system was able to
continuously track the fixture from 150 m away. Even when the agency
repeated the same SAE scenario at a much higher speed of 61 mph, the
SAE test did not challenge the system's image recognition in an
observable way. This shows that an ADB system's initial image
recognition capability is not challenged by the SAE test as it is in a
more realistic curve test, meaning that NHTSA is less confident that
the SAE test would result in an equivalent level of safety as the
actual-curve test that NHTSA is finalizing. The practical implications
of this is that glare will not be sufficiently controlled by the SAE
test compared to the actual-curve test adopted in this final rule.

[GRAPHIC] [TIFF OMITTED] TR22FE22.008

    As another example, SAE J3069 does include a sudden appearance test
(using the oncoming and preceding motorcycle fixtures) in which the
fixture lamps are activated when the test vehicle is between 155 m and
100 m from the fixture. The agency found, however, that this also does
not realistically simulate a curve. See Figure 9. On an 85 m left curve
at 26 mph, the ADB system recognized the final rule oncoming motorcycle
fixture at 20 m. On the SAE sudden appearance scenario, in contrast,
the ADB system performed better, activating a shaded area at 70 m.
Additional comparative data from the final rule scenarios and the SAE
test scenarios are presented and discussed in Section VIII.C.8, Test
Scenarios.
[GRAPHIC] [TIFF OMITTED] TR22FE22.009

BILLING CODE 4910-59-C
    NHTSA disagrees with SAE's comment to the extent that it suggests
that a final rule incorporating actual curves might not be objective or
repeatable. The final rule sets out a rational test procedure that
yields a clear answer based upon readings obtained from measuring
instruments and is capable of producing identical results when test
conditions are exactly duplicated.\87\ The final rule specifies the
specific scenarios NHTSA may test, including ranges and values for key

testing parameters (e.g., differing radii of curvature), and specific
numeric limits for the maximum allowable illuminance at certain
distances; there is thus no ambiguity with respect to the parameter
values NHTSA may select in compliance testing. Moreover, NHTSA has
conducted a repeatability analysis and has concluded that the finalized
test scenarios and procedures are repeatable (see Section VIII.C.11,
Repeatability).
---------------------------------------------------------------------------

    \87\ See, e.g., Chrysler Corp. v. Dept. of Transp., 472 F.2d
659, 676 (6th Cir. 1972).
---------------------------------------------------------------------------

    NHTSA did, however, agree that some of the proposed curve scenarios
were too stringent. With respect to oncoming glare scenarios, the final
rule eliminates the short right curve scenario and reduces the
distances at which glare on the medium and large right curves and the
short and medium left curves is evaluated. With respect to preceding
glare scenarios, the final rule includes a straight-path scenario and a
medium left curve scenario. The specifications for the radii of
curvature have also been slightly modified. These modifications and
other choices are explained in more detail later in the preamble.
    In general, NHTSA selected the final scenarios based on three
criteria:
    The scenario represents commonly-encountered roadway geometries and
vehicle interactions. To ensure that ADB systems operate safely, the
final scenarios should include at least the most common road geometries
and vehicle interactions. Because the adaptive driving beam is intended
for distance illumination at speeds at which the lower beam does not
provide adequate illumination--typically above 20 mph--these geometries
and interactions should be those common at these speeds.\88\
---------------------------------------------------------------------------

    \88\ See NPRM, pp. 51787-51788.
---------------------------------------------------------------------------

    A compliant lower beam could pass the scenario. We also generally
chose scenarios such that a compliant lower beam would be able to pass
the scenario. There were several reasons for this. First, this (in
conjunction with the requirement that areas of reduced intensity meet
the corresponding lower beam laboratory photometric requirements)
ensures that an area of reduced intensity, up to and including a full
lower beam, will meet the same level of safety (with respect to both
visibility and glare prevention) as current lower beams certified to
FMVSS No. 108. Second, this is consistent with the concept for the
proposal: Extending the current laboratory-based lower beam photometric
requirements (specifically, the photometric maxima regulating oncoming
and preceding glare) for use in a vehicle-level test to evaluate the
ability of an ADB system to minimize glare (both oncoming and
preceding).\89\ Because the track test was intended as an extension of
the current laboratory photometric requirements, the track test
requirements should (generally) be such that a lower beam (or area of
reduced intensity) that complies with the current laboratory
photometric requirements will also comply with the track test
requirements.
---------------------------------------------------------------------------

    \89\ See NPRM, pp. 51770, 51773.
---------------------------------------------------------------------------

    The scenario is generally within the capabilities of robustly-
designed internationally-available ADB systems. As noted above, the
field of view for current ADB systems is typically 25 degrees to the
left and right of the camera, and, as explained below,\90\ ADB
adaptation time--the time it takes an ADB system to recognize a
stimulus (once the stimulus is within the camera's field of view) and
dim the beam to a level that falls within the applicable glare limit--
is generally about 1 second. Therefore, NHTSA generally chose scenarios
such that it would be possible for an ADB system with such field of
view and response capabilities to pass the scenario. This is not to say
that all current ADB systems would necessarily be able to pass all the
final scenarios without any modifications. However, the agency intended
to select scenarios that were generally within the reach of current
technology (perhaps necessitating some additional improvements,
adjustments, or optimizations, depending on the ADB technology), to
facilitate timely deployment of ADB systems. NHTSA also recognized that
these systems have been in use in foreign markets for several years
with few, if any, apparent safety issues.\91\ We discuss and apply
these criteria in more detail in Section VIII.C.8, Test Scenarios.
---------------------------------------------------------------------------

    \90\ See Section VIII.C.5, ADB Adaptation Time.
    \91\ The fact that the final rule does not include all the
proposed scenarios does not mean that NHTSA has concluded that only
a relatively small set of narrowly circumscribed scenarios is
permissible in an FMVSS. In this case, NHTSA has concluded that
adopting a smaller set of test scenarios appropriately addresses
both the need for safety (including facilitating the timely
deployment of ADB systems) and practicability. This also does not
imply that FMVSS requirements must be tailored to the capabilities
of currently existing systems. See, e.g., Chrysler Corp. v. Dept. of
Transp., 472 F.2d 659, 673 (6th Cir. 1972) (``[T]he Agency is
empowered to issue safety standards which require improvements in
existing technology or which require the development of new
technology, and it is not limited to issuing standards based solely
on devices already fully developed.'').
---------------------------------------------------------------------------

4. Maximum Illuminance Criteria (Glare Limits)
    The NPRM included a set of photometric maxima to evaluate an ADB
system's ability to minimize glare in the track test (glare limits).
Because the current photometric test points from which the proposed
glare limits were derived are maxima, the agency proposed applying the
derived glare limits as maxima, so that any measured exceedance of an
applicable glare limit (except for momentary spikes) would be used to
determine compliance. The NPRM also extended the standard's ``design to
conform'' language to the proposed requirements, including the glare
limits.\92\ The NPRM also summarized the basis for the glare limits
(the full explanation for the derivation is given in the Feasibility
Study).
---------------------------------------------------------------------------

    \92\ As we explained in the NPRM, the proposal extended the
standard's longstanding ``design to conform'' language to the
proposed requirements because the concept of the rulemaking was to
extend the current headlamp requirements to ADB systems. We
therefore considered the continued appropriateness of ``design to
conform'' to be outside the scope of this rulemaking. However, this
extension in no way limits NHTSA's ability to revisit the issue of
design to conform in the future. Furthermore, if NHTSA were to
reconsider the design to conform language, it might not come to the
same conclusion it did when it originally adopted that language. As
we explained in the NPRM, NHTSA adopted the ``design to conform''
language when the standard was introduced in 1967 because it
accepted industry's contemporaneous representation that vehicle
lamps could not be manufactured to meet every single test point
without a substantial cost penalty unjustified by safety. We further
explained that, because lighting equipment design, technology, and
manufacturing have evolved and advanced since the late 1960's, NHTSA
might not come to the same conclusion were it to revisit this issue.
---------------------------------------------------------------------------

    The NPRM explained that the proposed glare limits deviate from SAE
J3069 in a few respects. First, two of the glare limits differ
slightly. At 60 m, SAE J3069 uses glare limits of 0.7 lux (oncoming)
and 8.9 lux (preceding) compared to the proposed 0.6 lux and 4.0 lux.
Second, SAE J3069 applies to a narrower range of distances (30 m-155 m)
than the proposed glare limits (15 m-220 m). Third, SAE J3069 applies
the glare limits only at the endpoints of the measurement ranges (i.e.,
155 m, 120 m, 60 m, and 30 m), while the NPRM applied the glare limits
throughout the entire measurement range. The proposal explained the
reasons for these deviations from SAE J3069.
Comments
    A few commenters (AAA, Consumer Reports, and Zoox) supported the
glare limits as proposed. Intertek agreed that the baseline glare limit
requirements should extend to the full distance ranges rather than only
at the four individual distances specified in SAE J3069. Several
commenters, however, contended that the glare limits were too stringent
and suggested a variety of modifications.

    SAE, Global, Ford, Toyota, the Alliance, and Auto Innovators
commented that the proposed glare limits were conservative and that
using absolute measurements of discomfort glare (the aspect of glare
that is painful or annoying, as opposed to the aspect of glare that
limits the ability to see other objects) is unreasonable and not
practicable. They recommended the final rule include reasonable
allowances for an ADB system to momentarily exceed the glare limits,
especially given the large number of proposed test scenarios. They also
stated that the proposed glare limits are well below the illuminance
provided by contemporary lower beams, including Insurance Institute for
Highway Safety (IIHS) top-rated lower beams for MY 2017 vehicles,
especially on curves. As noted earlier, SAE provided analyses and
graphs based on IIHS data on lower beam performance on different road
geometries, from straight roads to left and right curves of various
radii.\93\
---------------------------------------------------------------------------

    \93\ Auto Innovators also supplied an apparently somewhat
similar analysis of IIHS data (on pp. 12-13 of its comment).
However, the comment did not identify the geometry of the road (the
orientation of the headlamps to the photometer) for the
measurements, so the agency is unable to evaluate this submission.
In any case, NHTSA addresses this issue using the IIHS data
submitted by SAE and the agency's own testing of lower beams to the
scenarios included in the final rule.
---------------------------------------------------------------------------

    For those reasons, SAE, the Alliance, and Toyota argued that NHTSA
should evaluate the ratio of the ADB to lower beam illuminance. SAE
noted that this procedure is specified in SAE J3069, which requires the
measured illuminance to be no more than 25% above the measured lower
beam illuminance. SAE further stated that NHTSA's 2015 ADB Test Report
used a similar procedure, and that an UMTRI report found that 25% was
an acceptable maximum limit above the lower beam.\94\ Toyota commented
that following SAE J3069 in this respect would facilitate ADB
deployment across a wider range of vehicles.\95\ Auto Innovators also
argued for a similar 25% allowance (discussed below).
---------------------------------------------------------------------------

    \94\ DOT HS 808 209, Sept. 1994.
    \95\ SAE and other commenters also argued that comparing the
ratio of the illuminance from the adaptive beam to the lower beam
would also compensate for unaccounted for test variability such as
dips and bumps in the road. This is discussed below in Section
VIII.C.10.d, Allowance for Momentary Glare Exceedances.
---------------------------------------------------------------------------

    A few commenters expressed interest in the final rule accounting
for glare dosage. Toyota commented that there is no clear evidence that
exceeding the maximum illuminance for longer than 0.1 second leads to a
safety hazard any greater than what occurs with existing headlighting
systems on U.S. roads today. Mobileye similarly commented that a
distinction needs to be introduced between glaring that may cause
discomfort to other drivers and glaring which may pose a safety risk.
It asserted that, while the NPRM assumes that any glare exceedances for
more than 0.1 seconds are not acceptable, drivers commonly use
intentional, limited glaring as a signaling mechanism to other drivers.
Accordingly, Mobileye suggested allowing glare exceedances longer than
0.1 seconds. AAA commented that the final rule should not permit glare
exceedances lasting longer than 1 second because its research showed
that glare from an oncoming vehicle lasting approximately 1 second was
rated as highly distracting. Intertek believed that proposed 0.1 second
allowance would account for the majority of the issues related to glare
dosage, exposure, or perceptibility because any longer exceedance is
detectable by the human eye. Auto Innovators also asserted that the
final rule should account for glare dosage. (This is discussed further
below.)
    NHTSA received a few comments about the proposed measurement
distances. Intertek commented that regulating glare for distances
extending out to 220 m is unnecessary because the angular size and
position of oncoming headlamps at distances greater than 155 m mitigate
any harmful effects of glare. Intertek commented that testing out to
220 m creates additional complexity and testing costs. In contrast, AAA
suggested regulating glare beyond 220 m. They noted that European
specifications require camera recognition and reaction at distances of
400 meters (1,312 feet), and that intensity limits could be increased
from the current maximum of 150,000 cd to the European maximum of
430,000 cd if ADB systems are effective at this distance. SAE commented
that the proposed requirements for preceding glare are too stringent,
given the detection distance (120 m vs. 100 for the ECE) and the
minimum photometric requirements for rear lamps (2 cd vs. 4 cd for the
ECE).
    Valeo commented that the proposed maximum illuminance requirements
would result in wildly varying light output, especially compared to the
current ECE requirements, which result in a much more constant and
consistent light intensity. Valeo also suggested that the final rule
clarify that the requirements apply to the entire ADB system (both
left-hand and right-hand headlamps).
    Intertek suggested measuring luminance \96\ from the ADB system
headlamps rather than illuminance at the test fixture would provide
several benefits, including: The data collected from the test would
have a record which is very closely matched, and can be perceived and
analyzed in much the same way as what an actual driver of the stimulus
vehicle would have experienced; the recorded data can be viewed as a
map of luminous intensity (candela) emitted from the test vehicle,
which would be directly comparable to the existing photometry
requirements, and can be plotted as a function of time or approach
distance; over time, if this data is collected carefully and attention
is paid to those scenarios in which the driver of the stimulus vehicle
feels glared, a better quantitative baseline for and understanding of
glare can be established.
---------------------------------------------------------------------------

    \96\ ``Luminance'' refers to the luminous intensity produced by
a light source in a particular direction per solid angle, while, as
noted earlier, ``illuminance'' refers to the amount of light falling
on a surface. The unit of measurement for luminance is candela,
while the unit of measurement for illuminance is lux. A measure of
luminous intensity in candela can be converted to a lux equivalent
(and vice versa), given a specified distance.
---------------------------------------------------------------------------

    Auto Innovators stated that NHTSA should adopt a modified version
of the IIHS right-curve glare exposure criteria for all oncoming
scenarios.\97\ See Table 5. Auto Innovators contended that this would
be appropriate because the IIHS glare limits are intended to provide
consumers with a relative assessment of headlamp performance and it is
possible for a vehicle to drastically exceed the glare criteria in the
IIHS test and still comply with FMVSS No. 108; the IIHS protocol allows
exceedances in the form of cumulative exposures as opposed to hard
pass/fail limit at a single point in time, resulting in a series of
demerits (based on the percentage over the limit) for which it is
possible for a vehicle to achieve a ``Good'' rating while still
offering small amounts of glare. Auto Innovators recommended adopting a
similar method for establishing an allowable time exceedance for each
test range.
---------------------------------------------------------------------------

    \97\ Insurance Institute for Highway Safety. Headlight Test and
Rating Protocol, Version III (July 2018); Rationale and Supporting
Work for Headlight Test and Rating Protocol. (August 2015).

Table 5--Auto Innovators' Modified Maximum Illuminance Criteria Based on
                              IIHS Protocol
------------------------------------------------------------------------
                                                             Illuminance
                       Distance (m)                          limit (lx)
------------------------------------------------------------------------
30 to 59.9................................................             6

60 to 119.9...............................................           3.4
120 to 220................................................             1
------------------------------------------------------------------------

    Auto Innovators gave a few different arguments for adopting its
proposed glare limits. First, it claimed that the IIHS glare limits
better reflect modern headlighting systems. It noted that the proposed
glare limits are based, in part, on headlamps typical of the 1997 model
year, whereas the IIHS protocol is based on contemporary headlighting
systems. Next, Auto Innovators contended that the IIHS protocol
accounts for research indicating that the harmful effects of glare
depend on both peak illuminance and overall dosage of glare exposure.
Finally, Auto Innovators contended that the IIHS methodology accounts
for glare effects due to incidence angle whereas the Feasibility Study
does not. Auto Innovators recommended eliminating the 15-29.9 m
measurement range (for both oncoming and preceding scenarios) because
its test data showed not only that the least amount of failures
occurred in this interval but that the exceedance durations for all
failures in this range were 1.0 second or less.\98\
---------------------------------------------------------------------------

    \98\ Auto Innovators also argues that glare exceedances at these
short distances may be caused by swiveling of the headlamps. While
this only applies to swiveling beam ADB systems, Auto Innovators
believes that any safety standard should remain technology neutral.
---------------------------------------------------------------------------

    In addition to recommending NHTSA adopt its suggested glare limits,
Auto Innovators recommended that the final rule require passage of a
percentage of averaged individual illuminance readings to achieve
compliance instead of looking to the maximum recorded illuminance in
each measurement range. Specifically, Auto Innovators appeared to
suggest that NHTSA perform three test runs for each scenario and
average the maximum illuminance in each measurement range recorded for
each scenario. Then, it asks that NHTSA allow up to 15% of the averaged
illuminance readings to exceed its recommended glare limits by up to
25%. Auto Innovators cited the same UMTRI and NHTSA reports referenced
earlier, as well as three inconsequentiality petition grants as the
basis for the 25% allowance.\99\ Auto Innovators commented that the 15%
allowance comes from the turn signal test requirements in S14.9.3 of
FMVSS No. 108. It contended that this amount of performance variation
is consistent with the challenges of outdoor dynamic testing where
little previous experience exists, especially compared to the highly-
controlled laboratory photometric testing that has previously been
used. Auto Innovators commented that it would be difficult not to
attribute failures of illuminance readings to variances that could
appear in the novel and unique aspects of the test procedure, rather
than to quality control issues, particularly where the time and
complexity of the testing preclude conducting it on multiple ADB-
equipped vehicles. It also asserted that this approach is consistent
with the standard's design to conform language. Mobileye similarly
suggested specifying a pass/fail ratio for the measured illuminance
values in each specified measurement interval.
---------------------------------------------------------------------------

    \99\ 85 FR 39678 (July 1, 2020) (grant of petition for
inconsequential noncompliance for side marker lamp below photometric
minima); 85 FR 39679 (July 1, 2020) (grant of petition for
inconsequential noncompliance for rear reflectors below minima); 55
FR 37601 (Sept. 12, 1990) (grant of petition for inconsequential
noncompliance for taillamp exceeding maxima).
---------------------------------------------------------------------------

Agency response
    NHTSA agrees with the commenters that the proposed glare limits
were overly stringent at some geometries and measurement distances in
that a current, FMVSS No. 108-compliant lower beam would not have
complied with some of these requirements. The agency has therefore
modified the proposal by deleting the short right curve scenario and
modifying measurement distances for other specified radii of curvature.
NHTSA believes that these modifications reasonably ensure that a lower
beam that complies with the current FMVSS No. 108 photometry
requirements would be within the glare limits as applied in the
specified measurement ranges in each of the final scenarios. This is
discussed in further detail in Section VIII.C.8, Test Scenarios.\100\
---------------------------------------------------------------------------

    \100\ NHTSA anticipates that ADB systems could provide better
glare protection than current lower beams if dynamic vertical aim is
incorporated into the systems. Current lower beams will produce
glare on hills and undulating roads. Because of the nature of the
adaptive beam's area of unreduced intensity, it does not have the
same sensitivity to aim as a lower beam with respect to seeing
distance. For example, an ADB pattern could be aimed down more than
a lower beam (preventing glare even when the vehicle pitches) while
still providing appropriate seeing distance in directions where
glare protection is not required. However, the agency decided not to
require additional glare protection performance from ADB systems
beyond that currently produced by lower beams (except on right
curves) and anticipates aiming strategies might be incorporated into
ADB systems in order to maintain reasonable compliance margins.
---------------------------------------------------------------------------

    NHTSA disagrees with some commenters' suggestions to follow SAE
J3069 and only consider an ADB system as not complying with the glare
limits if the measured ADB illuminance exceeds 25% of lower beam
illuminance. The final rule differs from the proposal by eliminating
overly stringent scenarios and providing additional adjustments to
account for testing variability, including data filtering procedures
and an adjustment for vehicle pitch, in addition to the proposed
allowance for momentary glare exceedances. The agency believes that
these modifications obviate the need for any further glare limit
allowances. While more relaxed test requirements might facilitate ADB
deployment, they would not ensure that ADB systems function properly.
We believe that the final requirements and test procedures strike a
reasonable balance between visibility and glare prevention.
    Neither the UMTRI report nor the comments relating to the NHTSA
research cited by the commenters are persuasive. The UMTRI report
concerned the evaluation of inconsequentiality petitions, not the
appropriate magnitude of the lower beam maxima, which is the relevant
issue when considering the appropriate level for the glare limits.\101\
As explained in the NPRM, the proposed glare limits were based on FMVSS
No. 108's longstanding Table XIX photometric maxima. While the 2015 ADB
Test Report did examine how close the observed ADB illuminance values
were to the relevant glare limit, including an analysis of the effect
on the results of increasing the glare limits by up to 25%,\102\ the
analysis did not concern ``just noticeable differences'' or state or
imply that exceedances of up to 125% of the relevant glare limit were
inconsequential. Instead, the purpose of this analysis was to ``see
whether increasing the glare limit would have changed an exceeding
result to a non-exceeding result.'' \103\ The 2015 ADB Test Report also
examined the ratio of ADB illuminance to lower beam illuminance. This
analysis was intended to evaluate ADB functionality, not as a means of
evaluating ADB compliance. This was particularly useful because some of
the lower beam headlighting systems tested in the 2015 study were not
designed to meet the requirements

of FMVSS No.108. Using a ratio allowed for the comparison of basic ADB
functionality against the lower beam regardless of the photometric
standard to which the lower beam was designed.\104\
---------------------------------------------------------------------------

    \101\ See DOT HS 808 209, Sept. 1994, p. 9 (concluding that
``using 25% as a criterion for inconsequential noncompliance'' is
appropriate for lower-beam headlamps) (emphasis added).
    \102\ 2015 ADB Test Report, p. 133.
    \103\ Id.
    \104\ Although commenters did not suggest it, we also decided
not to adopt an adjustment such that if ADB illuminance exceeds an
applicable glare limit, the exceedance would be considered a
noncompliance only if the ADB illuminance exceeded the lower beam
illuminance (i.e., without a 25% cushion). The reasons for this are
the same as the reasons for not adopting the commenters'
recommendations.
---------------------------------------------------------------------------

    Regarding the distances at which to regulate glare, regulating
oncoming glare out to 220 m is appropriate. As the Feasibility Study
explained, at greater distances a smaller glare limit is appropriate
because, at greater distances, ``the glare source will be seen by the
oncoming driver at a smaller angle.'' \105\ NHTSA was able to test the
final scenarios out to this distance (where applicable) and did not
encounter any testing difficulties related to this distance. On the
other hand, NHTSA did not develop testing scenarios for oncoming glare
at distances greater than 220 m, and so is not prepared to test beyond
that distance. The reasons for regulating oncoming glare out to 220 m
are discussed in greater detail in Section VIII.D.4, Requirements for
area of unreduced intensity. NHTSA does agree with SAE that it is more
appropriate to test preceding glare only out to 100 m, and not the
proposed 120 m. The reasons for this are discussed in more detail in
Section VIII.C.8.g, Scenario 7: Preceding Straight.
---------------------------------------------------------------------------

    \105\ Feasibility Study, p. 23.
---------------------------------------------------------------------------

    The agency disagrees with Valeo's assertion that specifying the
glare limits as a stepwise (discontinuous) function of distance will
result in dramatic fluctuations in light output. The glare limits are
photometric maxima, not design requirements, and there is no reason to
think that manufacturers will design headlamps that suddenly increase
or decrease in brightness for reasons unrelated to road conditions.
Moreover, the laboratory requirements that reference the Table XIX
photometric maximum intensity limits preclude manufacturers from
producing areas of reduced intensity that vary as Valeo would suggest.
In fact, the output limits specified in Table XIX require lower beam
intensities (which is what the agency requires the ADB systems to
produce in the area of reduced intensity) well below those calculated
by Valeo at the further distances of the measurement subrange.
    While the final rule could have specified the glare limits as a
continuous function of distance, this would have been more complicated.
In any case, the stepwise specification is less stringent than
specifying glare limits as a continuous function of the closing
distance between the test vehicle and the test fixture. The glare
limits for each of the four specified ranges was derived from the
shortest distance in the range, and then applied to all the (further)
distances in the range. As the Feasibility Study explained, however,
the glare limits are derived to decrease as distance increases.\106\
Therefore, if the glare limits were specified as a continuous function
of distance, they would decrease throughout the interval as distance
increased. By specifying the glare limits as a stepwise function, the
glare limits are higher at the further distances in the interval than
they would have been if we specified them as a continuous function of
distance. This has the benefit of simplicity. It also essentially gives
manufacturers an additional margin for error than they would have had
if we specified the limits as a continuous function of distance. The
final rule has, however, incorporated Valeo's suggestion to clarify
that the requirements apply to the entire ADB system.
---------------------------------------------------------------------------

    \106\ Id.
---------------------------------------------------------------------------

    Intertek makes an interesting suggestion for quantifying perceived
glare. However, based on the agency's stated goals of minimizing the
cost impact of the regulation and providing a pathway for introduction
of ADB systems for use on U.S. roadways as quickly as possible, the
final rule does not adopt Intertek's suggestion. To do so would require
additional research to inform the agency on how such changes would
affect the glare and photometry limits specified, as well as any costs
associated with requiring the agency and the industry to switch from
test methods designed around measuring illuminance at the test vehicle
to measuring luminance. The agency simply has no data to support such a
change at this time.
    NHTSA understands Auto Innovators' suggestion to adopt the IIHS
glare limits as related to their general argument that the proposed
glare limits and test scenarios were too stringent. As explained
earlier, NHTSA agreed with this point to some extent and modified the
measurement distances, test scenarios, and allowances accordingly.
However, the agency does not adopt Auto Innovators' glare limits for
two reasons.
    First, the glare limits suggested by Auto Innovators are three
times the proposed limits, which are based on the current photometry
requirements. The intent of this rulemaking is to permit ADB without
increasing glare from levels currently on the road. NHTSA's testing
showed that Auto Innovators' suggested limits do not represent glare
produced by compliant lower beams under the controlled driving
situations that are part of the ADB test, particularly for straight and
left curve scenarios. For the left curve and straight path scenarios,
testing of the Fusion and Volvo demonstrated that a considerable margin
is achieved with the proposed glare limits.\107\ See Table 6. These
same types of margins are present throughout our lower beam testing.
This confirms that these limits provide a boundary to protect the
public from additional glare beyond what is currently experienced on
the roads today. See also the discussions of lower beam performance on
various scenarios in Section VIII.C.8, Test Scenarios. The commenter's
suggested limits would significantly increase that boundary and permit
substantially higher glare on the roads.
---------------------------------------------------------------------------

    \107\ The Fusion used had not been rated by IIHS. The Volvo was
rated ``acceptable'' by IIHS.

                        Table 6--Lower Beam Illuminance Margin for Proposed Glare Limits
----------------------------------------------------------------------------------------------------------------
                           Range  (m)                               Glare limit     Max illum.      Margin  (%)
----------------------------------------------------------------------------------------------------------------
                                        Volvo 210 m left curve at 42 mph
----------------------------------------------------------------------------------------------------------------
150.0-120.0.....................................................             0.3           0.051              83
119.9-60.0......................................................             0.6           0.158              74
59.9-30.0.......................................................             1.8           0.788              56
29.9-15.0.......................................................             3.1           2.118              32
----------------------------------------------------------------------------------------------------------------

                                       Fusion 400 m right curve at 54 mph
----------------------------------------------------------------------------------------------------------------
70.0-60.0.......................................................             0.6           0.415              31
59.9-30.0.......................................................             1.8           0.933              48
29.9-15.0.......................................................             3.1           1.394              55
----------------------------------------------------------------------------------------------------------------

    Second, the agency believes the proposed oncoming glare limits
(which are derived from the Table XIX left side photometric maxima) are
most appropriate for any oncoming scenario--including right curves--
because they were derived from limits designed specifically for
oncoming traffic (which in the United States are typically to the left,
except on right curves). Auto Innovators' suggested limits may be
appropriate for the right side of lower beams where the compromise
between seeing distance and glare places greater value on seeing toward
the right side. This is appropriate for a static beam pattern that
limits glare in all horizontal directions no matter where the other
road user is located. If one thinks of oncoming interactions as being
oriented in terms of either straight, left curve, or right curve, two
of these three (straight and left curve) have the other vehicle toward
the left of the subject vehicle's headlamps. So, for those two
situations, it is better to allow more potential glare to the right
side of the road (where other road users are less likely to be) in
order to provide some seeing light in that direction. For the remaining
right curve situation, the beam is still limited, but less so, and some
glare is expected to account for better seeing distance toward the
right for the other two situations. No such compromise needs to be
applied for ADB. The ADB pattern creates a reduced illumination area to
the left when the other vehicle is to the left and an unreduced area to
the right. When the other vehicle is toward the right, the same
protection can now be applied to those encounters as to the straight
and left, without sacrificing seeing distance. As such, the agency is
using the glare limits derived for the left side oncoming curve
scenario for the right curve scenario.
    The agency acknowledges the relationship between dosage (the
product of illuminance and duration) and the disabling effects of
glare. For glare control, the IIHS headlamp rating procedure uses a
derivative of dosage (distance for which a limited illuminance is
exceeded). However, the quantified crash risks associated with
exceeding these limits is not clear. Research the agency conducted in
2008 began to explore this relationship, noting that ``specification of
the integrated (summed) values throughout the segment would be more
likely to provide control for glare recovery, but would involve
headlamp light measurement procedures that are more complex than those
currently used to determine if a headlamp meets the FMVSS 108
requirements.'' \108\ Until this final rule, the basic structure of the
headlighting regulation (goniometer--photometry) did not provide a
foundation for which glare dosage could be readily measured and
regulated. As such, the agency has not focused its research in this
area. While NHTSA agrees that a qualitative relationship exists, the
agency has not established, and does not know of, a quantified
relationship between glare dosage and crash risk.
---------------------------------------------------------------------------

    \108\ DOT HS 811 043 Nighttime Glare and Driving Performance:
Research Findings, 2008.
---------------------------------------------------------------------------

    Another limitation of IIHS's method is that it considers all glare
doses equal (except for distances between 5 m and 10 m). The impacts of
glare, however, are also related to the angle between the glare source
and the line of sight of the viewer. The glance pattern of drivers in
nighttime glare situations is not well understood, as some drivers may
be inclined to look toward the glare source effectively causing the
angle between the line of sight and the glare source to be zero.\109\
To the extent that a driver follows driver's education recommendations
and does not look at the glare source, glare doses in roadway
interactions are not equally impactful at all distances, as the angle
between the glare source and the line of sight is smaller at far
distances. Such an effect is reflected in the current photometric
tables and was, in fact, taken into account in the glare limits
derivation in the Feasibility Study, in that the glare limits are
smaller at greater distances.\110\ NHTSA therefore disagrees with Auto
Innovators that the IIHS study accounts for glare effects due to
incidence angle.\111\
---------------------------------------------------------------------------

    \109\ 2007 Report to Congress, pg. iv.
    \110\ See Feasibility Study, p. 23.
    \111\ In addition, we note that the negative impacts of glare
are not limited to disabling glare, but are also related to the
annoyance and even painful experience of other roadway users.
NHTSA's 2008 research concluded that ``the peak illuminance, rather
than the dosage, was the primary factor associated with rated
discomfort.'' DOT HS 811 043 Nighttime Glare and Driving
Performance: Research Findings, 2008.
---------------------------------------------------------------------------

    NHTSA is therefore finalizing the glare limits as proposed. Future
development of glare dosage as full vehicle dynamic testing for
headlighting systems continues to mature is of interest to the agency.
    With respect to Auto Innovators' comments regarding specifying an
allowance of 25% over the glare limits, we disagree with this for the
reasons given above regarding the evaluation of the ratio of adaptive
driving beam to lower beam illuminance. NHTSA also does not find the
cited inconsequentiality petition grants to be persuasive because they
did not concern headlamps, and, except for one of the petitions, did
not concern glare. The agency was also not persuaded by the suggestions
by Auto Innovators and Mobileye to adopt a pass/fail ratio or to
average a number of test runs in order to mitigate test-related
variability. Such procedures, while occasionally specified in an FMVSS,
would be unusual. In any case, we do not believe this is necessary here
for two reasons. First, we believe the final test procedure already has
sufficient allowances for test-related variability (an allowance for
momentary glare exceedances, a vehicle pitch adjustment, and the
application of a low-pass filter with a cutoff frequency of 35
Hz).\112\ Second, we conducted a repeatability analysis and found the
final test procedure to be repeatable.\113\
---------------------------------------------------------------------------

    \112\ See Section VIII.C.10, Data Acquisition and Measurement.
    \113\ See Section VIII.C.11, Repeatability.
---------------------------------------------------------------------------

5. ADB Adaptation Time
    The NPRM included a 0.1 second or 1 m magnitude allowance for
momentary glare exceedances. This was intended to account for
variations in illumination due not to the ADB system but to
uncontrolled or uncontrollable

testing variables. This differs from an allowance for an adaptation
time, which would account for the operation of the ADB system--
specifically, the time it takes an ADB system to recognize a stimulus
(once the stimulus is within the camera's field of view) and respond by
dimming the beam, switching from an area of unreduced intensity to an
area of reduced intensity. SAE J3069 specifies a 2.5 second maximum ADB
adaptation time during the sudden appearance test drive. (The NPRM did
not include a ``sudden appearance'' scenario because the system's
ability to respond quickly is exercised by the shorter-radii curve
scenarios.) The NPRM did not propose a time limit within which an ADB
system would be required to respond to a stimulus, but sought comment
on whether one should be included in the regulation.
Comments
    Some commenters interpreted the 0.1 second allowance for momentary
glare exceedances as an adaptation time allowance.\114\ Mobileye, Ford,
Honda, Volkswagen, and Auto Innovators contended that 0.1 second is not
technically feasible and the final rule should specify a duration
greater than 0.1 second because ADB systems need time to recognize the
stimulus and modify the beam. Mobileye and Ford stated that without
this, ADB systems would behave erratically, and Mobileye stated that it
would result in many more false positives, leading to reduced
visibility. Honda asserted that an insufficient time allowance would
dis-incentivize the deployment of systems that operate over a wide
range of conditions, and might especially be an issue on curves with a
radius of 320-380 ft, on which an opposing vehicle will enter the ADB
vehicle's field of view suddenly at a close distance. Honda suggested
an allowance for an adaptation time sufficient to ensure that ADB
systems have an appropriate amount of time to react to the sudden
appearance of other vehicles or when environmental lighting changes
dynamically when driving.
---------------------------------------------------------------------------

    \114\ The proposed allowance for momentary glare exceedances
(intended to account for uncontrolled test-related variability) is
discussed in Section VIII.C.10.d.
---------------------------------------------------------------------------

    Mobileye, Ford, Volkswagen, and Auto Innovators specifically
supported the 2.5 second ``reaction time'' specified in SAE J3069. Ford
commented that 2.5 seconds is reasonable based on its extensive
experience with auto beam switching systems similar to ADB systems
available internationally. Mobileye also noted that ECE R48 defines the
minimal distance below which glaring is not allowed. Auto Innovators
commented that its test data showed that a majority of exceedances were
less than 2.0 seconds, with only a few exceedances over 2.5 seconds
(limited to scenarios in which the stimulus vehicle was difficult to
detect, such as the stationary motorcycle). Mobileye, Volkswagen, and
Auto Innovators commented that 2.5 seconds would still be an
improvement over human-driver reaction time.
    In contrast, AAA asserted that 2.5 seconds is inordinately long,
and that the reaction time should be decreased to approximately 1
second, based on its research which showed that glare from an oncoming
vehicle lasting approximately 1 second was rated as highly distracting.
Agency Response
    Although the final rule does not specify an allowable ``adaptation
time,'' the agency does agree that the final rule should generally take
into account how long it takes a typical, well-designed ADB system to
respond. Typical ADB adaptation times are a little over 1 second. An
ADB test report published by SAE in 2016 reported a reaction time of
about 1.1 seconds.\115\ NHTSA's testing showed comparable times,
ranging from .56 seconds to 1.22 seconds when suddenly exposed to a
stimulus.\116\ These reported adaptation times are much less than the
2.5 seconds specified in SAE J3069.
---------------------------------------------------------------------------

    \115\ Assessment of Adaptive Driving Beam Photometric
Performance (SAE 2016-01-1408), p. 3. This included the time it took
for an experimenter to turn on the stimulus vehicle headlamps at a
predetermined distance, so the actual system response time was
shorter than this.
    \116\ 2015 ADB Test Report, p. 92.
---------------------------------------------------------------------------

    In addition, at the speeds the track tests are conducted, the test
vehicles will cover a significant amount of the measurement distance
within an adaptation time of 2.5 seconds (nearly 28 m at 25 mph, or 55
m at 50 mph). For example, the SAE sudden appearance scenarios specify
that the fixture lamp be suddenly exposed when the test vehicle is
between 155 m and 100 m from the fixture. At 55 mph (24.6 m/s) the test
vehicle will have traveled 61.5 m in 2.5 s. If the fixture lamps were
activated at 100 m, this means that the test vehicle would be about 40
m from the fixture by the time the 2.5 second allowance had elapsed.
This would mean that only one illuminance value (at 30 m) would be
evaluated by the SAE test. Similarly, in a real-world vehicle
interaction, with two vehicles approaching each at 70 mph (31.3 m/s)
each, if the ABD system takes 2.5 s to react, the two vehicles will
have traveled 157 m before the ADB system reacts.
    After consideration of the studies and data discussed above, NHTSA
believes that an ADB adaptation time of 2.5 seconds is exceedingly
long. The final rule does not specify an adaptation time, however,
because the final scenario parameters have generally been specified so
that glare is not regulated until the fixture has been within the field
of view of a typical ADB system (25 degrees to each side) long enough
for the system to react (for example, in the small left curve scenario
the fixture is within the camera's field of view for approximately 1.24
s before the fixture enters the measurement distance range for that
scenario). There are some exceptions to this. For some of the smaller-
radii curve scenarios, the final rule begins regulating glare at a
distance at which a typical ADB system might not have had time to
react. Even here, however, there is not a need for an adaptation time
because a typical ADB system would not exceed the glare limits even at
these distances. At these further distances, because there will be a
relatively wide angle between the test vehicle headlamps and the test
fixture, the upper beam illuminance at those angles (and distances) is
not likely to exceed the applicable glare limit. There is also no
apparent safety need for directing high illuminance at such wide
angles. These points are covered in more detail in the sections below
for the various test scenarios.
6. Test Fixture Specifications
    The NPRM identified test fixtures, including those specified in SAE
J3069, as a regulatory alternative. The NPRM explained that SAE J3069
specifies four test fixtures: An opposing car/truck fixture; an
opposing motorcycle fixture; a preceding car/truck fixture; and a
preceding motorcycle fixture. The NPRM explained that the SAE fixtures
are fitted with lights intended to simulate actual vehicle lamps; the
lamps are intended to represent reasonable worst-case for intensity and
location and promote repeatability. For headlamp representations, the
SAE standard specifies a lamp projecting 300 cd of white light in a
specified manner and angle instead of actual headlamps. In addition to
being intended to represent a reasonable worst-case condition, the SAE
J3069 rationale also states a ``concern that if the actual lower beam
headlamps were used on the opposing vehicle test fixture the large
gradients present in typical lower beam patterns would cause
unnecessary test

variability.'' \117\ For the taillamp representations, SAE J3069
specifies lamps emitting no more than 7 cd of red light in a specified
manner and angle. The fixtures are fitted with photometers positioned
near where a driver's eyes or the rearview/side mirrors would be
located to measure illumination from the ADB test vehicle
headlamps.\118\ The lamp and photometer locations are based on ``median
location values provided by [the University of Michigan Transportation
Research Institute].'' \119\
---------------------------------------------------------------------------

    \117\ SAE J3069, p. 4.
    \118\ SAE J3069 5.5.2 and Figures 1 and 2 (opposing vehicle
fixture); 5.5.3 and Figures 3 and 4 (preceding vehicle fixture).
    \119\ SAE J3069, p. 3.
---------------------------------------------------------------------------

    The NPRM identified and sought comment on potential issues with the
SAE J3069 fixture specifications, particularly whether using simulated
lamps instead of actual vehicle lamps was sufficiently realistic. We
stated that test fixtures may encourage an ADB system designed to
ensure identification of test fixtures rather than actual vehicles,
which might not adequately ensure that the system performs
satisfactorily when faced with a wide range of real-world vehicles and,
particularly, real-world vehicle lighting. We stated that we were not
confident that the lamps specified in SAE J3069 represented a worst-
case scenario. As one example of this, we noted that the minimum
intensity allowed for a taillamp is 2.0 cd at H-V and as low as 0.3 cd
at an angle of 20 degrees. These values are considerably lower than the
7.0 cd lamp specified in SAE J3069. We therefore sought comment on the
extent to which narrowly-defined lamps can be used to establish
performance requirements that reasonably ensure an ADB system will
recognize and adapt appropriately to the wide range of lighting
configurations permitted under FMVSS No. 108. We also noted, with
respect to the concern raised in SAE J3069 that using actual lower beam
headlamps on the opposing vehicle fixtures would lead to test
variability, that in the real world an ADB system must be able to
identify headlamps from many different types and models of vehicles; if
an ADB system was so sensitive to actual headlamp gradients that those
gradients affected ADB system performance, the variability would be
attributable to the ADB system, not the test.
Comments
    The agency received several comments relating to test fixture
specifications. While many manufacturers urged NHTSA to adopt SAE
J3069,\120\ some commenters identified potential concerns with the SAE
J3069 fixtures. Mobileye commented that the major drawback of SAE J3069
is the use of synthetic stimulus light sources, which presents a
challenge because in actual driving scenarios, the system is trained to
ignore the types of synthetic light sources specified in SAE J3069
because they are more likely to be lights from houses, driveways, or
other non-vehicle sources. Mobileye pointed out that vehicle headlamps
differ from the SAE fixtures in shape, power source (DC), and having a
distinct non-uniform light dispersion pattern. Mobileye suggested that
placing lamps on static fixtures will force an ADB system to react to
light sources even when it positively recognizes them as not being part
of a vehicle. Mobileye recommended that the fixture closely resemble a
``uniform'' or ``standard'' vehicle with lamps representative of those
approved by FMVSS No. 108 instead of the static fixtures specified in
SAE J3069, so as not to force the ADB system to downgrade its real-life
performance to comply with a synthetic test.\121\ Intertek commented
that it is possible for image recognition software to be adjusted to
specifically identify and respond to the SAE J3069 test fixture and
test track without necessarily ensuring adequate real-world
performance.
---------------------------------------------------------------------------

    \120\ See Section VIII.O, Regulatory Alternatives.
    \121\ Auto Innovators also suggested using standardized
headlamps and taillamps in lieu of the proposed broad range of
actual stimulus vehicles.
---------------------------------------------------------------------------

    We also received comments on the proposed stimulus vehicle lighting
that are equally relevant to test fixture lighting. Bosch recommended
that, to ensure system robustness, NHTSA specify stimulus vehicles with
a wide variety of light source technologies and consider utilizing a
reference publication such as the Ward's Automotive Yearbook to stay
current with rapidly evolving headlamp technology. Honda noted that the
NPRM did not specify which headlamp beams should be activated on the
stimulus vehicle and suggested that the final rule clarify that this is
the lower beam. Auto Innovators raised the possibility of a situation
where the regulation specifies a specific vehicle or vehicle component,
but the item is later determined to be noncompliant or subject to
manufacturer in-cycle design changes or modifications. Auto Innovators
suggested that this potential for non-compliance presents an
unforeseeable uncertainty to the compliance process, because such
changes will not always be known at the time a manufacturer of the ADB
vehicle conducts self-certification testing or to a third-party
conducting compliance testing for the agency.
Agency Response
    The final rule specifies test fixtures conforming to SAE J3069 with
respect to the types of fixtures and photometer placement. The final
rule departs from SAE J3069 by specifying vehicle lamps from high-
selling vehicles instead of lamps intended to simulate vehicle
lighting.
    The final rule specifies the same four types of fixtures specified
in SAE J3069: An oncoming car/truck fixture; a preceding car/truck
fixture; an oncoming motorcycle fixture; and a preceding motorcycle
fixture. The final rule follows the SAE specifications for the
locations of the stimulus lighting. SAE based these locations on data
regarding the typical mounting locations of vehicle lighting. NHTSA
agrees that these locations are appropriate, and within the FMVSS No.
108 mounting location requirements.
    The rule also follows SAE J3069 for the locations of the
illuminance meters. SAE based these locations on data regarding typical
driver's eye heights and mounting locations for the rearview/side
mirrors. The illuminance meter locations specified in the final rule
are the same as in the proposal, with one exception. In its recent
revisions to SAE J3069, SAE revised the specifications for the
placement of the illuminance meters (corresponding to two side-view
mirrors) on the preceding motorcycle fixture. The revision notes that
the figure depicted in the prior version of the practice showed the
mirrors to be 0.2 m from the centerline of the rear position lamp,
which is not consistent with the FMVSS No. 111 required minimum. FMVSS
No. 111 requires that each motorcycle have a mirror ``mounted so that
the horizontal center of the reflective surface is at least 279 mm
outward of the longitudinal centerline of the motorcycle.'' \122\ The
revised version of SAE J3069 shows the motorcycle mirror separation to
be 0.4 m, which is consistent with the FMVSS No. 111 required minimum.
The specification in the final rule adopts this revised specification.
---------------------------------------------------------------------------

    \122\ S10.1.
---------------------------------------------------------------------------

    We did, however, agree with Mobileye that--as we also tentatively
concluded in the NPRM--the simulated lamps specified in SAE J3069 would
not be sufficiently realistic. We therefore agreed with Mobileye's and
Auto Innovators' suggestions to use standardized vehicle lamps on the
fixtures. The final rule therefore departs

from SAE J3069 and specifies actual vehicle lamps for the fixtures. The
reasons for this choice are explained in more detail below. The final
rule specifies headlamp assemblies from a 2018 Ford F-150 (halogen) and
a 2018 Toyota Camry (LED). For motorcycles, the final rule specifies a
5.75 inch headlamp assembly from a 2018 Harley Davidson Sportster using
an HB2 replaceable light source.\123\ The rule specifies right and left
taillamp assemblies from a 2018 Ford F-150 incandescent rear
combination lamp and right and left tail lamp assemblies from a 2018
Toyota Camry combination lamp. For motorcycles, the final rule
specifies a layback LED taillamp assembly from a 2018 Harley Davidson
Roadster.
---------------------------------------------------------------------------

    \123\ This is different than the motorcycle headlamp used in
NHTSA recent testing. For that testing, NHTSA used a 5.75 inch
bullet headlamp kit from a 2018 Harley Davidson Roadster using an
HB2 replaceable light source (part #68593-06). After that testing
and before the publication of this final rule, that part went out of
production and has been replaced with part #68297-05B.
---------------------------------------------------------------------------

    There were several reasons for specifying actual vehicle lamps.
NHTSA agrees with the concerns Mobileye identified regarding the use of
synthetic fixture lighting and with Intertek that specifying synthetic
lighting could result in vehicle manufacturers programming systems to
recognize unrealistic fixtures, thus decoupling compliance test
performance from actual performance.\124\ The agency's intent was to
specify a variety of light source technologies that are common in the
market in order to assess how an ADB system performs with respect to
light systems it will encounter while in actual use on the roads. This
will discourage manufacturers from designing specifically to fixture
lamps lacking characteristics typical of actual automotive lamps (e.g.,
non-uniform illuminance, variations in shape). Using actual vehicle
lamps also reduces the cost of manufacture of the test fixture (since
the highly specialized SAE fixture lighting is much more expensive).
The agency agrees with Bosch that it is important that the lamps on the
fixtures continue to be representative of vehicle lamps in use. To that
end, NHTSA envisions future technical rulemakings to amend the lamps
specified in the regulatory text.
---------------------------------------------------------------------------

    \124\ SAE J3069 MAR2021 added a note requiring that any pulse
width modulation or similar frequency control be sufficiently above
the commercial power grid frequency and updated the conical angle
specification. Even with these changes, NHTSA still believes that
the finalized vehicle lighting is more appropriate.
---------------------------------------------------------------------------

    The agency also does not believe that the synthetic light sources
specified in SAE J3069 represent a worst-case scenario. As NHTSA
explained in the NPRM, the minimum taillamp intensities allowed by
FMVSS No. 108 (2.0 cd at H-V and as low as 0.3 cd at 20 degrees) are
considerably lower than the 7.0 cd lamp specified in SAE J3069. NHTSA
also does not agree with SAE that specifying actual vehicle headlamps
would result in excessive variability, but continues to believe, as
stated in the NPRM, that gradients in typical headlamp beam patterns
would likely only affect the repeatability of the test if the reaction
by the ADB system changes based on this difference. If this is the
case, the ADB system will have this issue in actual use (especially
since the specified headlamps are from high-selling vehicles and
therefore common on the road), and this should not be considered
variability attributable to the test, but a failing of the ADB system.
In any case, NHTSA's testing showed that the tested ADB system was
generally able to recognize the fixtures fitted with these lamps.
Comparative test data for the SAE fixtures and the final rule fixtures
is presented in the discussions for each scenario (see Section
VIII.C.8).
    The final rule also clarifies various aspects of the test
procedures related to the fixture lamps. It clarifies that the stimulus
headlamps will have the lower beam activated and aimed per the SAE
Recommended Practice J599 Lighting Inspection Code (J599) procedures,
as applicable. The final rule also specifies how to power the fixture
lamps. SAE J3069 does not specify how to power the test-fixture
lighting; this could leave open the possibility of powering the fixture
in ways that are dissimilar to how actual automotive head and taillamps
are powered, and potentially lead to ambiguities in how performance is
measured. Accordingly, the final rule specifies that the lamps will
have been energized for at least 5 minutes before each test scenario
trial is performed.
    The agency considered Mobileye's comment that the fixture should
resemble a ``standard'' vehicle but decided not to adopt this. Using a
fixture incorporating vehicle elements (e.g., hood, grill) raises
issues of which elements to specify and how to specify them. NHTSA did
consider implementing a portion of a vehicle in the fixtures, such as a
partial front or rear section of a vehicle that would include the
original equipment lamps as mounted in the production vehicle.
Including a portion of the actual vehicle body would provide a more
real-world stimulus with the added detail of some elements of vehicle
shape and light reflections on the body surfaces. However, while this
option was not examined in NHTSA's research, our research did not
demonstrate any significant difference in ADB response between actual
stimulus vehicles and the test fixtures we are specifying, suggesting
that adding detail elements to the fixture is not necessary.\125\
---------------------------------------------------------------------------

    \125\ SAE J3069 MAR2021 allows the fixture to be ``constructed
in a manner that represents the intended vehicle type to avoid false
readings that the stimulus fixture is not a vehicle'' (sections
<IP_ADDRESS> and <IP_ADDRESS>). As noted in the text, we considered but did
not examine this alternative. However, we believe, based on the
results of our testing (see Section VIII.C.2, Test Fixtures vs.
Stimulus Vehicles), that specifying actual vehicle lamps makes the
fixtures sufficiently realistic so that the ADB system will
recognize the fixture as a vehicle.
---------------------------------------------------------------------------

    With respect to Auto Innovators' comment regarding the possibility
of a noncompliance of actual vehicle components used as a stimulus in a
compliance test, NHTSA recognizes this possibility, but anticipates
that the laboratory test procedures will provide for confirming that
the vehicle lamps used on the test fixture comply with the applicable
FMVSS No. 108 photometry requirements.
7. Test Fixture Placement
    The proposal specified stimulus vehicles in the adjacent left lane
to evaluate oncoming glare. To evaluate preceding glare, it essentially
specified the stimulus vehicle either in the same lane as the test
vehicle or in the adjacent left lane.
    The final rule, while specifying test fixtures, generally follows
the NPRM approach. The test fixture will be placed in the adjacent left
lane (from the perspective of the test vehicle) to evaluate both
oncoming glare and preceding glare, essentially the same placement as
proposed.\126\ See Figure 10 (Figures 27-28 in the regulatory text).
This corresponds to Fixture Position 2 in SAE J3069. The final rule
does not specify fixtures situated similarly to SAE Positions 1 and 3.
In the SAE test method, fixtures placed in those locations are
primarily intended to simulate curves; the final rule includes curved-
path scenarios, so simulating curves with strategic fixture placement
is not necessary. The final rule also specifies that the projection of
the fixture lamp's optical axis onto the road surface should be tangent
to the road edge at the location of the photometer, and that the
fixture be centered in the lane.
---------------------------------------------------------------------------

    \126\ The test vehicle will be driven within the right adjacent
lane and will not change lanes.

---------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TR22FE22.010

BILLING CODE 4910-59-P
    NHTSA acknowledges that it is common in real-world driving for
preceding vehicles to be located in the same lane or in the adjacent
right lane. However, the agency believes that simply testing with the
preceding fixture in the left adjacent lane will not result in a loss
of information about ADB system performance. The purpose of the testing
is to evaluate whether the ADB system is working in an integrated
fashion; this can be done on either side. While real-world situations
with a stimulus to the right side are common, it is reasonable to
expect that if a system functions on the left it will also function on
the right. Further, the final rule also has tests that include curves
to the right, where the detection system is exercised (limited to
oncoming and limited distances) on the right side of the field of view.
8. Test Scenarios \127\
---------------------------------------------------------------------------

    \127\ The test scenario numbering used in the preamble and in
the final rule regulatory text (at Table XXII) differs somewhat from
the test scenario number in the ADB test report and repeatability
assessment docketed with this final rule.
---------------------------------------------------------------------------

a. Scenario 1: Oncoming Straight
    The NPRM proposed testing for oncoming glare in a straight-path
test scenario at speeds from 60 mph to 70 mph at measurement distances
of 15 m to 220 m.
Comments
    ALNA, Toyota, SAE, and the Alliance commented that the proposed
glare limits are at or well below those regularly occurring today from
lower beams, including, the commenters appeared to suggest, in a
straight-path scenario. SAE and the Alliance stated that the glare
limits are not reasonable if lower beams, including IIHS ``Good''-rated
lower beams, would fail to comply. SAE provided a graphical analysis
(based on IIHS data) of lower beam illuminance on a straight road (from
0 m to 125 m) for nine MY 2017 IIHS Top Safety Picks, all with FMVSS
108-compliant IIHS-rated ``Good'' headlamps. The graph shows that
almost all those headlamps complied with the proposed glare limits at
all proposed measurement distances.
Agency Response
    NHTSA is finalizing the proposed specifications for this scenario,
including the proposal to evaluate illuminance from 15 m to 220 m. The
rule thus evaluates glare across a broader range of distances than SAE
J3069, which evaluates glare at 30 m, 60 m, 120 m, and 155 m,
respectively. The reasons for choosing this range are discussed in the
NPRM (83 FR at 51778-51781) and elsewhere in this preamble.
    The available data indicate that current lower beams can comply
with the glare limits in this scenario. The IIHS data submitted by SAE
show that the lower beams for the 9 vehicles for which data was
provided were generally within the glare limits on a straight road for
all the distances for which the final rule regulates glare. NHTSA's
testing also shows that current lower beams would pass this scenario.
NHTSA tested the lower beams of a MY 2019 Ford Fusion and MY 2016 Volvo
XC90 in this scenario. The measured illuminance of the lower beams was
found to be within the glare limits by a considerable margin at all
distances. See Figure 11 and Figure 12.\128\
---------------------------------------------------------------------------

    \128\ The illuminance measured from the higher-mounted
photometer representing the truck driver eye point, is, as expected,
lower than that measured from the lower-mounted photometer intended
to represent a passenger car driver's eye point. For that reason,
some of the test data included in this preamble may not report the
illuminance values measured from the higher-mounted illuminance
meter.

---------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TR22FE22.011

    NHTSA's analysis and testing also indicate that current ADB systems
can reasonably be expected to comply with this scenario. As Figure 7
makes clear, the fixture is within the ADB camera's field of view at
the beginning of the measurement range, at less than 5 degrees left of
the center of the field of view. (As noted earlier, the field of view
of current ADB systems extends to about 25 degrees left and right.)
Accordingly, the ADB system should have sufficient time to detect and
react to the fixture stimulus lamps and adjust the beam. The agency's
ADB test data confirms this. For example, the ADB system we tested was
within the glare limits at all distances when tested with the oncoming
car/truck fixture. See Figure 13. Additionally, NHTSA's 2015 testing
showed that an older ADB system was able to pass this scenario even
when tested with stimulus vehicles, both moving and stationary.\129\
---------------------------------------------------------------------------

    \129\ 2015 ADB Test Report at p. 103 (Table 23) (results for
Audi show adaptive beam within the glare limits at all distances on
the straight scenario, with both a static and dynamic stimulus
vehicle). Audi indicated that the shaded area of the adaptive beam
complied with the FMVSS No. 108 lower beam requirements.
---------------------------------------------------------------------------

    The ADB system also passed the SAE scenario that is the closest
analog to this scenario (with the car/truck test fixture in Position
2), and NHTSA did not see a significant difference between performance
on the NHTSA and SAE test protocols here.\130\ See Figure 13.
---------------------------------------------------------------------------

    \130\ Agency testing showed some anomalies when testing with the
motorcycle fixtures (both the final rule fixture and the SAE
fixture). For that reason, the results of that testing are discussed
separately. See Appendix C.

---------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TR22FE22.012

b. Scenario 2: Oncoming Small Left Curve
    The NPRM provided for testing oncoming glare on left curves with
radii of 98 m to 116 m, at speeds from 20 mph to 30 mph, for the full
range of 15 m to 220 m.
Comments
    In addition to general comments from several manufacturers that the
proposal would require ADB systems to produce less glare than current
FMVSS No. 108-compliant lower beams, particularly on curves, SAE
provided a graphical analysis of IIHS data of illuminance from nine
``Good''-rated lower beams from 0 m to 125 m on a 150 m left curve. The
data show that almost all the lower beams were within the glare limits
in this entire range, except that one vehicle occasionally exceeded the
glare limits between 15 m and 60 m, one vehicle exceeded the glare
limits at 15 m, and a couple of vehicles exceeded the glare limits
between about 60 m and 90 m.
    The Alliance, SAE, OICA, and SMMT commented that current ADB
systems would not comply with this scenario because it would
necessitate a camera field of view wider than provided on current ADB
systems. The Alliance stated that the camera visibility needed to
detect a stimulus vehicle on this curve is almost 45 degrees (with a
median) and 40 degrees (without a median). Both the Alliance and SAE
contended that, should this scenario be retained, camera visibility
would have to be extended, which would increase costs, potentially
diminish performance in the more critical central portion of the
visibility zone, and create dis-harmonization, limiting the
availability of ADB systems in the United States. SAE also stated that
upper beams at greater than 15 degrees left or right are not as bright
as lower beams straight ahead, and at an angle of 40 degrees the light
toward a stimulus vehicle driver is low. SAE stated that this is
supported by the fact that millions of semiautomatic beam systems on
the roads today are equipped with the same or similar forward vision
cameras and detection algorithms as ADB systems and have not resulted
in glare complaints. This suggests, SAE asserted, that wide angle
visibility (i.e., beyond 25 degrees) is unnecessary and precludes any
need to test on curves of these radii.
    Honda commented that the proposed 0.1 s or 1 m allowance for
momentary spikes does not allow enough time for an ADB system to
respond to sudden changes in stimulus lighting, and that this
especially might be an issue on curves with a radius of 98 m-116 m, on
which an opposing vehicle will enter the ADB system's field of view
suddenly at a close distance.
Agency Response
    The final rule retains this scenario but modifies the distances at
which illuminance from the ADB system is evaluated: The measurement
range now begins at 59.9 m \131\ instead of the proposed 220 m. The
reasons for this are explained below.
---------------------------------------------------------------------------

    \131\ In the regulatory text this is specified as ``less than 60
m.'' Other distance specifications are stated similarly. The
preamble discussion simplifies this for ease of exposition.
---------------------------------------------------------------------------

    First, the available data indicate that current, FMVSS 108-
compliant lower beams might not comply with the glare limits at
distances greater than 60 m but would generally comply at closer
distances. The IIHS data submitted by SAE show that almost all the
tested lower beams were almost fully within the glare limits in the
modified distance range (15 m-59.9 m), while some of the lower beams
exceeded the glare limits for distances greater than 60 m. NHTSA's
testing also shows that current lower beams would pass this modified
scenario. NHTSA tested two vehicles with lower beams activated on an 85
m left curve, and both vehicles performed well with considerable
margins. See Figure 14.

[GRAPHIC] [TIFF OMITTED] TR22FE22.013

    Next, NHTSA believes that this modified specification is within the
capabilities of most current ADB systems. On a curve with a 100 m
radius, at the highest vehicle speed specified for this scenario (30
mph), the fixture will enter the camera's field of view (25 degrees) at
77 m (see Figure 7). At the distance at which the final rule begins
evaluating the system's illuminance (59.9 m), the fixture is therefore
well within the camera's field of view (at about 21 degrees). The
fixture is not only within the camera's FOV, but has been within the
FOV for 1.24 s, which is a sufficient time for an ADB system to react.
NHTSA acknowledges that for shorter radii in the specified range, the
time elapsed between the fixture entering the system's field of view
and the test vehicle reaching the beginning of the evaluation range
(59.9 m), may not provide sufficient time for an ADB system to react
and switch from an area of unreduced intensity (i.e., upper beam) to an
area of reduced intensity. For example, on a curve with an 85 m radius
at 30 mph, the fixture will enter the camera's field of view at 63 m.
At 59.9 m, the fixture will have been within the system's FOV for 0.13
s. The agency does not, however, expect this to result in a
noncompliance because at that distance the headlamps are at a large
enough angle to the photometer that the upper beam should be within the
glare limits. (Agency testing generally showed that the upper beam was
within the glare limits at angles greater than 20 degrees. There are no
upper beam photometry requirements at angles wider than 12 degrees. At
12 degrees, Table XVIII specifies (depending on the type of upper beam)
a minimum of, at most, 1,500 cd (at horizontal) and 1,000 cd (at 2.5D).
    NHTSA's ADB test data bear this out. When NHTSA tested an ADB
system at 29 mph on a curve at the upper bound of the range (115 m),
the ADB system detected and reacted to the fixture prior to the
measurement range. See Figure 15. On the other hand, when testing the
ADB system on a curve at the lower bound of the radius range (85 m),
the system did not react to the fixture and dim the beam until 41 m--
which is after the specified beginning of the measurement range (59.9
m). See Figure 16. However, the illuminance (the upper beam) at these
large angles was below the applicable glare limit, and the system was
able to react and adapt the beam before the geometry was such that the
narrower angle of the upper beam would exceed the glare limit.

[GRAPHIC] [TIFF OMITTED] TR22FE22.014

    NHTSA also tested the SAE scenario that is the closest analog to
this scenario (with the oncoming fixtures in Position 1) and observed
no glare limit exceedances. See Figure 17. However, the illuminance
was, for closer distances, significantly lower than the illuminance
measured during the corresponding final rule scenario. This is because,
as the test vehicle approaches the SAE fixture, the fixture moves more
and more off-angle from the test vehicle as the distance closes,
resulting in lower-than-expected illuminance.

[GRAPHIC] [TIFF OMITTED] TR22FE22.015

    NHTSA notes that this scenario, as modified, does not evaluate
illuminance from 60 m to 220 m, so it would not test whether the ADB
system switched from an upper beam to an adaptive beam in this range.
In the NPRM the agency tentatively concluded that it was important to
regulate illuminance in the full range of 15 m-220 m. However, as
explained above, NHTSA decided the full range is unnecessary because an
upper beam projected at angles larger than 20 degrees is not glaring at
distances beyond those at which we are evaluating illuminance in this
scenario.
c. Scenario 3: Oncoming Medium Left Curve
    NHTSA proposed testing for oncoming glare on left curves with radii
of 223 m to 241 m, at speeds of 40-45 mph, for the full range of 15-220
m.
Comments
    NHTSA received one comment specifically related to this scenario.
SAE provided a graphical analysis of IIHS illuminance data (out to 125
m) for nine lower beams on a 250 m left curve showing that all the
lower beams were within the glare limits, except for two headlamps that
had some exceedances between 60 m and 110 m. As noted earlier, some
commenters argued more generally that the proposed glare limits were so
stringent that even currently-compliant lower beams would exceed them.
Agency Response
    The final rule modifies the measurement range, which now begins at
150 m instead of the proposed 220 m. The rationale for this is
analogous to the rationale for limiting the measurement distances for
the small left curve.
    First, the available data indicate that compliant lower beams would
generally comply with these requirements. As explained earlier, this
(in conjunction with the requirement that areas of reduced intensity
meet the corresponding lower beam laboratory photometric requirements)
means that an area of reduced intensity, up to and including a full
lower beam, will meet the same level of safety (with respect to both
visibility and glare prevention) as current lower beams certified to
FMVSS No. 108. The IIHS data submitted by SAE shows that almost all the
tested lower beams complied with the glare limits for the distances for
which data was reported. NHTSA's testing also shows that current lower
beams would pass this modified scenario; both lower beams NHTSA tested
had illuminance values within the glare limits by a considerable
margin. See Figure 18.

[GRAPHIC] [TIFF OMITTED] TR22FE22.016

    Next, NHTSA's analysis also indicates that the modified
specifications are within the field-of-view and adaptation time
capabilities of most current ADB systems. For example, on a 230 m curve
at 45 mph, over two seconds elapse between the fixture entering the
field-of-view and the vehicle reaching the measurement range (150 m),
providing the ADB system sufficient time to react and adapt the beams.
As with the small left curve, however, for shorter radii in the
specified range, the time elapsed between the fixture entering the ADB
system's field of view and the vehicle reaching the beginning of the
measurement range may not provide sufficient time for the ADB system to
adapt and switch from an area of unreduced intensity to an area of
reduced intensity. For example, on a 210 m curve, only .57 seconds
elapse. However, as with the small left curve, at those distances the
headlamps are at a large enough angle to the photometers that the upper
beam should be within the applicable glare limit.
    Again, NHTSA's ADB test data bears this out. NHTSA tested an ADB
system on a 210 m left curve at 44 mph. See Figure 19. The measured
illuminance values were within the glare limits except for two
exceedances lasting less than 0.1 s (which would not be considered a
noncompliance because they are within the allowance for momentary glare
exceedances). The ADB system reacted to the fixture at 120 m. Prior to
that (i.e., from 150 m to 121.9 m), the ADB system was projecting an
upper beam, but the upper beam was within the glare limits.
    In comparison, when testing the most analogous SAE test scenario
(with the fixture in Position 1) there were no glare limit exceedances,
and, at closer distances, the SAE test scenario resulted in lower
illuminance values than were measured on the actual left curve.
[GRAPHIC] [TIFF OMITTED] TR22FE22.017

    In addition, as noted earlier for the small left curve scenario,
although the final rule reduces the start of the measurement distance
in this scenario from 220 m to 150 m, this should not present a risk
that oncoming vehicles will experience glare outside of 150 m for the
reasons discussed earlier.
d. Scenario 4: Oncoming Large Left Curve
    The NPRM specified testing for oncoming glare on left curves with
radii of 335-396 m, at speeds of 50-55 mph, from 15 m to 220 m.
Comments
    NHTSA did not receive any comments that related specifically to
this curve. Commenters argued more generally that currently-compliant
lower beams would not always comply with the glare limits, especially
on curves, and that there might not be sufficient time for the ADB
system to react to the stimulus lighting.
Agency Response
    The final rule adopts this scenario essentially as proposed (the
largest-specified radius of curvature has been rounded up). Both a
lower beam and an ADB system can reasonably be expected to comply with
the glare limits throughout this range.
    The available data indicate that current FMVSS No. 108-compliant
lower beams can comply with the glare limits in the full measurement
range. The IIHS data submitted by SAE did not include a left curve with
a radius this large. However, the IIHS data did include lower beam
performance on a 250 m radius left curve and a straight road. As
explained in the preceding section for the medium left curve scenario,
all the IIHS-tested headlamps were essentially within the glare limits
at all distances for which data was reported (out to about 125 m) on
both the 250 m left curve and the straight road. Because the curve in
this scenario is essentially between a 250 m left curve and a straight
road, it is reasonable to extrapolate that the lower beams tested by
IIHS would also have complied on left curves with radii greater than
250 m. NHTSA's test data confirms this. Both the Fusion and the Volvo
lower beams were within the glare limits on this curve. See Figure 20.
[GRAPHIC] [TIFF OMITTED] TR22FE22.018

    These specifications are also within the capabilities of current
ADB systems. On a curve with a 335 m radius at the highest speed
specified for this scenario (55 mph), the fixture will enter the
camera's field of view (25 degrees) at 283 m (see Figure 7). At the
distance at which we will begin evaluating the system's illuminance
(220 m), the fixture is therefore well within the camera's field of
view (at about 20 degrees), and has been within the FOV for 1.27 s,
which is sufficient time for an ADB system to react.
    NHTSA's testing confirmed this. The ADB system tested was generally
able to respond and shade the fixture in this scenario. See Figure 21.
The system reacted at 185 m and performed well from a recognition
standpoint. The area of reduced intensity exceeded the limits in the
60-120 m range as well as the 30-60 m range. Because these exceedances
last longer than 0.1 s. and occur while the vehicle pitch is less than
0.3 degrees from the average pitch throughout the run, these
exceedances would be considered possible noncompliances. However, these
failures are relatively marginal, and the beam pattern could be
modified to fully comply with this scenario.
[GRAPHIC] [TIFF OMITTED] TR22FE22.019

    As with the other oncoming left curve scenarios, the closest SAE
test analogue is with an oncoming fixture in Position 1. Again, NHTSA's
testing showed that, compared to NHTSA's test, the SAE test resulted in
much lower illuminance at close distances than on an actual curve. See
Figure 22. Thus, data indicate again that the two test methods can
yield different results, and that the actual curve test is preferable
because it would be more evaluative of real-world performance.
[GRAPHIC] [TIFF OMITTED] TR22FE22.020

BILLING CODE 4910-59-P
e. Scenario 5: Oncoming Medium Right Curve
    The NPRM proposed regulating glare on right curves with a radius of
223 m to 241 m, at speeds of 40-45 mph, from 15 m to 220 m.
Comments
    SAE provided a graphical analysis of illuminance data for nine IIHS
``Good''-rated lower beams on a 250 m radius right curve from 0 m to
125 m and

stated that it demonstrated none of those lower beams would meet the
proposed glare limits. Other commenters argued more generally that
current lower beams would exceed the proposed glare limits, especially
on curves. Intertek commented that NHTSA should limit the range for
right-hand curves to account for lower beam patterns at 3 degrees
right. Stanley ran simulations for a 232 m radius right curve and
commented that the proposed glare limits appeared to be inconsistent
with the current photometric requirement for lower beams at several
points (especially from 1R to 3R). It asked that the agency reconsider
the proposed glare limits and make them consistent with the current
regulatory requirements for lower beams.
Agency Response
    The final rule retains this scenario but revises the measurement
range to begin at 50 m instead of the proposed 220 m.
    NHTSA agrees with the commenters that current compliant lower
beams--especially ones that perform well on the IIHS test--would likely
not comply with the glare limits from 51 m-220 m. The IIHS data
submitted by SAE show that almost all the lower beams tested by IIHS
exceeded the glare limits at distances of 60 meters and greater on a
250 m right curve. NHTSA also examined IIHS lower beam data for a 2020
Toyota Camry with ``Good''-rated LED lower beams.\132\ IIHS measured
that vehicle on a 250-m radius curve to have a 5-lux line at 79.5 m
\133\ (70 m is the minimum without receiving demerits), which would
exceed the applicable glare limit at that distance (0.6 lux).
---------------------------------------------------------------------------

    \132\ See www.iihs.org/ratings/vehicle/toyota/camry-4-door-sedan/2020#headlights (last accessed Dec. 18, 2020).
    \133\ Corresponding to approximately 0.3D, 7R.
---------------------------------------------------------------------------

    After considering the comments, NHTSA has determined that these
results should have been generally expected based on a comparison of
the oncoming glare limits and the longstanding Table XIX lower beam
photometry requirements that regulate lower beam design. The oncoming
glare limits were derived from the Table XIX left-side maxima (700 cd
at 1U, 1.5 L to L and 1,000 cd at 0.5 U, 1.5L to L).\134\ On a right
curve, however, the fixture enters the lower beam pattern from the
right side and traces a trajectory across the beam pattern from right
to left (See Figure 7). The Table XIX right-side maxima (1,400 cd at
1.5U, 1R to R and 2,700 cd at 0.5U, 1R to 3R) are higher than the left-
side maxima. In addition, unlike on the left side, the right-side
photometry is not limited at 0.5U extending indefinitely horizontally.
The left-side photometry is limited by the line 0.5U, 1.5L-L. The
right-side photometry is limited by 0.5U, 1R-3R. While right-side
photometry is ultimately limited at 1.5U, 1R-R, this line provides
considerably more flexibility to provide light down the right side.
Consequently, the Table XIX right-side maxima, on which current lower
beams are based, permit intensities that exceed the oncoming glare
limits, which were derived from the left-side maxima. Indeed, data show
that current compliant lower beams exceed the derived glare limits on
the right side at distances greater than 50 m. More specifically, based
on the IIHS data presented by SAE, exceedances at about 3R and greater
(corresponding to measurement distances of greater than about 50 m) are
found, and many fewer glare limits exceedances to the left of 3 degrees
right. Accordingly, the final rule revises this scenario so that the
measurement range does not start until 50 m.
---------------------------------------------------------------------------

    \134\ Feasibility Study, p. 23.
---------------------------------------------------------------------------

    The agency notes that even with this modification, the glare limits
in this final rule are still (as Stanley suggested) more stringent than
currently allowed by the Table XIX right-side maxima from 1R to
3R.\135\ However, this level of stringency is reasonable and provides a
manageable design range. The lower beam photometry was designed to
provide a generic beam to prevent glare regardless of the actual road
and traffic conditions; it was not customized to provide glare
protection to oncoming vehicles on a right curve. Because most
situations in which an oncoming vehicle can be glared will occur with
the oncoming vehicle to the left, the existing Table XIX lower beam
photometry requirements require shading the left side and permit more
light on the right side. However, the adaptive driving beam is not, and
need not be, an all-purpose beam like a conventional lower beam. It is
clear in the photometry tables that the appropriate glare limits for
oncoming situations are the left-side maxima in Table XIX, on which the
oncoming glare limits are based. These limits should, to the extent
possible, apply to oncoming glare, including from the right-side. In
any case, the agency believes that current lower beams would generally
comply with the glare limits as applied in this scenario with the
revised measurement distance range.
---------------------------------------------------------------------------

    \135\ In Appendix A, we provide additional data and discussion
on this.
---------------------------------------------------------------------------

    Indeed, both IIHS and NHTSA lower beam test data demonstrate that
compliant lower beams, including high-rated IIHS beams, would generally
be within the glare limits in this revised scenario. The IIHS data
submitted by SAE shows that for distances between 15 m and 60 m, most
of the lower beams were within the glare limits. Vehicles 1 and 7 seem
to take the most advantage of the flexibilities provided toward the
right side beyond 3 degrees in performing well in the IIHS right-curve
test, and the lower beams on both vehicles were below the glare limits
within 50 m. This demonstrates that a vehicle can both perform well on
the IIHS right-curve distance rating and stay within the glare limits
in this final rule's revised scenario.
    NHTSA's testing also showed that current lower beams can pass this
revised scenario. NHTSA tested two lower beams on a 210 m right curve,
and both were within the glare limits at all distances within the
specified measurement range. See Figure 23. The agency also saw similar
results in our 2015 testing, which (among other things) evaluated lower
beam illuminance on a 231 m right curve, and found that the lower beams
exceeded the glare limits at 60 meters and greater, and was within the
glare limits from 15 m to 60 m.\136\
---------------------------------------------------------------------------

    \136\ 2015 ADB Test Report, p. 193 (Fig. 85, Mercedes Trial 82
[lower beam]); p. 63 (Mercedes test vehicle modified by manufacturer
to produce a FMVSS No. 108 compliant beam pattern).

---------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TR22FE22.021

    NHTSA notes that these data from contemporary lower beams differ
somewhat from data on 1990s-era lower beams presented in the
Feasibility Study. Specifically, Figure 9 in the Feasibility Study,
which displayed a lower beam pattern typical of MY 1997 vehicles, seems
to indicate that lower beams would likely be within the oncoming glare
limits on the right side of the beam pattern illustrated in Figure 9.
However, as Auto Innovators pointed out in its comment, lower beam
design has changed since 1997. NHTSA believes it is reasonable to
assume that at least some manufacturers are supplying more light at or
just above the horizon for horizontal angles greater than 3 degrees
right (without violating the 1,400 cd maximum) than in the past in
order to perform well on the IIHS tests.\137\ Lower beams that are
designed to perform well on the IIHS test may thus be more likely to
fail the glare limits in the ADB track test, even if the system is
projecting an area of reduced intensity onto the fixture. This is
compounded by the effect of vehicle pitch: With higher intensity light
at larger vertical angles of the beam pattern, slight changes in pitch
can push the higher intensity portion of the lower beam upwards and
cause the oncoming glare limit to be exceeded. Further, at angles
beyond 3 degrees right, the glare limits begin to veer dramatically
from the flexibilities provided in the current Table XIX requirements
(specifically, the right-side maxima). Accordingly, the oncoming glare
limits, in conjunction with the revised measurement distances, are
consistent with the angular limits of the current lower beam
photometry. The track test continues the longstanding flexibilities for
lower beam design on the right side beyond 3 degrees.
---------------------------------------------------------------------------

    \137\ Comment from Alliance for Automotive Innovation (July 31,
2020) (NHTSA-2018-0090-0219), p. 11 (Fig. 5, Low-Beam Headlight
Intensity Pattern from IIHS Headlight Rating.
---------------------------------------------------------------------------

    The modified specifications for this scenario are also within the
capabilities of typical ADB systems. Because illuminance is evaluated
starting at 50 m from the fixture, there is more than enough time for
an ADB system to detect and react to the fixture (more than 7 seconds
on a 230 m radius curve).
    The agency's ADB test data bear this out. When testing an ADB
system on a 210-meter radius right curve, the illuminance was within
the glare limits except for some limited exceedances, which can readily
be addressed by minor changes in the design of the area of reduced
intensity. See Figure 24. Similarly, the 2015 testing with actual
stimulus vehicles showed that even an older ADB system was able to pass
a right curve (231 m) oncoming scenario at 15 m to 50 m.\138\
---------------------------------------------------------------------------

    \138\ 2015 ADB Test Report, p. 193 (Fig. 85, Mercedes Trial 83
[ADB]); p. 63 (Mercedes test vehicle modified by manufacturer to
produce a FMVSS No. 108 compliant beam pattern).

---------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TR22FE22.022

    The ADB system NHTSA tested had more exceedances when tested to the
most closely analogous SAE J3069 scenario (with the test fixture in
Position 3) compared to NHTSA's test. See Figure 25. This is because at
the measurement distances in this scenario, Fixture Position 3 is in
the bright (right-side) portion of the beam pattern, while the fixture
in NHTSA's test scenario is in the less-bright portion of the beam
pattern (center-right to center-left).
[GRAPHIC] [TIFF OMITTED] TR22FE22.023

    NHTSA notes that this scenario does not evaluate the illuminance
from the ADB system from 50 m-220 m, so it would not test whether the