weight-based attributes would avoid the above-mentioned disincentive
for the use of lightweighting technology by taking vehicle curb weight
out of the standards determination.
    After taking these considerations into account, EPA and NHTSA have
decided to propose standards for HD pickups and vans based on a ``work
factor'' attribute that combines vehicle payload capacity and vehicle
towing capacity, in pounds, with an additional fixed adjustment for
four-wheel drive (4wd) vehicles. This adjustment would account for the
fact that 4wd, critical to enabling the many off-road heavy-duty work
applications, adds roughly 500 lb to the vehicle weight. Under our
proposal, target GHG and fuel consumption standards would be determined
for each vehicle with a unique work factor. These targets would then be
production weighted and summed to derive a manufacturer's annual fleet
average standards.
    To ensure consistency and help preclude gaming, we are proposing
that payload capacity be defined as GVWR minus curb weight, and towing
capacity as GCWR minus GVWR. We are proposing that, for purposes of
determining the work factor, GCWR be defined according to SAE
Recommended Practice J2807 APR2008, GVWR be defined consistent with
EPA's criteria pollutants program, and curb weight be defined as in 40
CFR

86.1803-01. We request comment on the need to establish additional
regulations or guidance to ensure that these terms are determined and
applied consistently across the HD pickup and van industry for the
purpose of determining standards.
    Based on analysis of how CO2 emissions and fuel
consumption correlate to work factor, we believe that a straight line
correlation is appropriate across the spectrum of possible HD pickups
and vans, and that vehicle distinctions such as Class 2b versus Class 3
need not be made in setting standards levels for these vehicles.\71\ We
request comment on this proposed approach.
---------------------------------------------------------------------------

    \71\ Memorandum from Anthony Neam and Jeff Cherry, U.S.EPA, to
docket EPA-HQ-OAR-2010-0162, October 18, 2010.
---------------------------------------------------------------------------

    We note that payload/towing-dependent gram per mile and gallon per
100 mile standards for HD pickups and vans parallel the gram per ton-
mile and gallon per 1,000 ton-mile standards being proposed for Class 7
and 8 combination tractors and for vocational vehicles. Both approaches
account for the fact that more work is done, more fuel is burned, and
more CO2 is emitted in moving heavier loads than in moving
lighter loads. Both of these load-based approaches avoid penalizing
truck designers wishing to reduce GHG emissions and fuel consumption by
reducing the weight of their trucks. However, the sizeable diversity in
HD work truck and van applications, which go well beyond simply
transporting freight, and the fact that the curb weights of these
vehicles are on the order of their payload capacities, suggest that
setting simple gram/ton-mile and gallon/ton-mile standards for them is
not appropriate. Even so, we believe that our proposal of payload-based
standards for HD pickups and vans is consistent with the NAS Report's
recommendation in favor of load-specific fuel consumption standards.
    These attribute-based CO2 and fuel consumption standards
are meant to be relatively consistent from a stringency perspective.
Vehicles across the entire range of the HD pickup and van segment have
their respective target values for CO2 emissions and fuel
consumption, and therefore all HD pickups and vans would be affected by
the standard. With the proposed attribute-based standards approach, EPA
and NHTSA believe there should be no significant effect on the relative
distribution of vehicles with differing capabilities in the fleet,
which means that buyers should still be able to purchase the vehicle
that meets their needs.
(c) Proposed Standards
    The agencies are proposing standards based on a technology analysis
performed by EPA to determine the appropriate HD pickup and van
standards. This analysis, described in detail in draft RIA Chapter 2,
considered:
     The level of technology that is incorporated in current
new HD pickups and vans,
     The available data on corresponding CO2
emissions and fuel consumption for these vehicles,
     Technologies that would reduce CO2 emissions
and fuel consumption and that are judged to be feasible and appropriate
for these vehicles through the 2018 model year,
     The effectiveness and cost of these technologies for HD
pickup and vans,
     Projections of future U.S. sales for HD pickup and vans,
and
     Forecasts of manufacturers' product redesign schedules.
    Based on this analysis, EPA is proposing the CO2
attribute-based target standards shown in Figure II-1 and II-2, and
NHTSA is proposing the equivalent attribute-based fuel consumption
target standards, also shown in Figure II-1 and II-2, applicable in
model year 2018. These figures also shows phase-in standards for model
years before 2018, and their derivation is explained below, along with
alternative implementation schedules to ensure equivalency between the
EPA and NHTSA programs while meeting statutory obligations. Also, for
reasons discussed below, separate targets are being established for
gasoline-fueled (and any other Otto-cycle) vehicles and diesel-fueled
(and any other Diesel-cycle) vehicles. The targets would be used to
determine the production-weighted standards that apply to the combined
diesel and gasoline fleet of HD pickups and vans produced by a
manufacturer in each model year.

[GRAPHIC] [TIFF OMITTED] TP30NO10.018

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    \72\ The NHTSA proposal provides voluntary standards for model
years 2014 and 2015. Target line functions for 2016-2018 are for the
second NHTSA alternative described in Section II.C(d)(ii).

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

[GRAPHIC] [TIFF OMITTED] TP30NO10.019

    Described \73\ mathematically, EPA's and NHTSA's proposed functions
are defined by the following formulae:

    \73\ The NHTSA proposal provides voluntary standards for model
years 2014 and 2015. Target line functions for 2016-2018 are for the
second NHTSA alternative described in Section II.C(d)(ii).

EPA CO2 Target (g/mile) = [a x WF] + b
NHTSA Fuel Consumption Target (gallons/100 miles) = [c x WF] + d

Where:

WF = Work Factor = [0.75 x (Payload Capacity + xwd)] + [0.25 x
Towing Capacity]
Payload Capacity = GVWR (lb)-Curb Weight (lb)
xwd = 500 lb if the vehicle is equipped with 4wd, otherwise equals 0
lb
Towing Capacity = GCWR (lb)-GVWR (lb)
Coefficients a, b, c, and d are taken from Table II-7 or Table II-
8.\74\
---------------------------------------------------------------------------

    \74\ The NHTSA proposal provides voluntary standards for model
years 2014 and 2015. Target line functions for 2016-2018 are for the
second NHTSA alternative described in Section II.C(d)(ii).

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

[GRAPHIC] [TIFF OMITTED] TP30NO10.020

[GRAPHIC] [TIFF OMITTED] TP30NO10.021

    These targets are based on a set of vehicle, engine, and
transmission technologies assessed by the agencies and determined to be
feasible and appropriate for HD pickups and vans in the 2014-2018
timeframe. Much of the information used to make this technology
assessment was developed for the recent 2012-2016 MY light-duty vehicle
rule. See Section III.B for a detailed analysis of these vehicle,
engine and transmission technologies, including their feasibility,
costs, and effectiveness in HD pickups and vans.
    To calculate a manufacturer's HD pickup and van fleet average
standard, the agencies are proposing that separate target curves be
used for gasoline and diesel vehicles. The agencies estimate that in
2018 the target curves will achieve 15 and 10 percent reductions in
CO2 and fuel consumption for diesel and gasoline vehicles,
respectively, relative to a common baseline for current (model year
2010) vehicles. An additional two percent reduction in GHGs would be
achieved by the EPA program from a proposed direct air conditioning
leakage standard. These reductions are based on the agencies'
assessment of the feasibility of incorporating technologies (which
differ significantly for gasoline and diesel powertrains) in the 2014-
2018 model years, and on the differences in relative efficiency in the
current gasoline and diesel vehicles. The resulting reductions
represent roughly equivalent stringency

levels for gasoline and diesel vehicles, which is important in ensuring
our proposed program maintains product choices available to vehicle
buyers.
    The NHTSA fuel consumption target curves and the EPA GHG target
curves are equivalent. The agencies established the target curves using
the direct relationship between fuel consumption and CO2
using conversion factors of 8,887 g CO2/gallon for gasoline
and 10,180 g CO2/gallon for diesel fuel.
    It is expected that measured performance values for CO2
would generally be equivalent to fuel consumption. However, as
explained below in Section II. E. (3), EPA is proposing an alternative
for manufacturers to demonstrate compliance with N2O and
CH4 emissions standards through the calculation of a
CO2-equivalent (CO2eq) emissions level that would
be compared to the CO2-based standards, similar to the
recently promulgated light-duty GHG standards for model years 2012-
2016. For test families that do not use this compliance alternative,
the measured performance values for CO2 and fuel consumption
would be equivalent because the same test runs and measurement data
would be used to determine both values, and calculated fuel consumption
would be based on the same conversion factors that are used to
establish the relationship between the CO2 and fuel
consumption target curves (8887 g CO2/gallon for gasoline
and 10,180 g CO2/gallon for diesel fuel). In this case, for
example, if a manufacturer's fleet average measured compliance value
exactly meets the fleet average CO2 standard, it will also
exactly meet the fuel consumption standard. The proposed NHTSA fuel
consumption program will not use a CO2eq metric. Measured
performance to standards would be based on the measurement of
CO2 with no adjustment for N2O and
CH4. For manufacturers that choose to use the EPA
CO2eq approach, compliance with the CO2 standard
would not be directly equivalent to compliance with the NHTSA fuel
consumption standard.
(d) Proposed Implementation Plan
(i) EPA Program Phase-In MY 2014-2018
    EPA is proposing that the GHG standards be phased in gradually over
the 2014-2018 model years, with full implementation effective in the
2018 model year. Therefore, 100 percent of a manufacturer's vehicle
fleet would need to meet a fleet-average standard that would become
increasingly more stringent each year of the phase-in period. For both
gasoline and diesel vehicles, this phase-in would be 15-20-40-60-100
percent in model years 2014-2015-2016-2017-2018, respectively. These
percentages reflect stringency increases from a baseline performance
level for model year 2010, determined by the agencies based on EPA and
manufacturer data. Because these vehicles are not currently regulated
for GHG emissions, this phase-in takes the form of target line
functions for gasoline and diesel vehicles that become increasingly
stringent over the phase-in model years. These year-by-year functions
have been derived in the same way as the 2018 function, by taking a
percent reduction in CO2 from a common unregulated baseline.
For example, in 2014 the reduction for both diesel and gasoline
vehicles would be 15% of the fully-phased-in reductions. Figures II-1
and II-2, and Table II-7, reflect this phase-in approach.
    EPA is also proposing to provide manufacturers with an optional
alternative implementation schedule in model years 2016 through 2018,
equivalent to NHTSA's proposed first alternative for standards that do
not change over these model years, described below. Under this option
the phase-in would be 15-20-67-67-67-100 percent in model years 2014-
2015-2016-2017-2018-2019, respectively. Table II-8, above, provides the
coefficients ``a'' and ``b'' for this manufacturer's alternative. As
explained below, the stringency of this alternative was established by
NHTSA such that a manufacturer with a stable production volume and mix
over the model year 2016-2018 period could use Averaging, Banking and
Trading to comply with either alternative and have a similar credit
balance at the end of model year 2018.
    Under the above-described alternatives, each manufacturer would
need to demonstrate compliance with the applicable fleet average
standard using that year's target function over all of its HD pickups
and vans starting in 2014. EPA also requests comment on a different
regulatory approach to the phase-in, intended to reduce the testing and
certification burden on manufacturers during the 2014-2017 phase-in
years, while achieving GHG reductions on the same schedule as the
proposed phase-in. In this alternative approach, each manufacturer
would be required to demonstrate compliance with the final 2018
targets, but only over a predefined percentage of its HD pickup and van
production. The remaining vehicles produced each year would not be
regulated for GHGs. Thus this approach would have the effect of setting
final standards in 2014 that do not vary over time, but with an
annually increasing set of regulated vehicles. The percentage of
regulated vehicles would increase each year, to 100 percent in 2018. We
think it likely that manufacturers would leave the highest emitting
vehicles unregulated for as long as possible under this approach,
because these vehicles would tend to be the costliest to redesign or
may simply be phased out of production. We therefore expect that, to be
equivalent, the percentage penetration each year would be higher than
the 15-20-40-60 percent penetrations required under the proposed
approach. EPA requests comment on this regulatory alternative, and on
what percentage penetrations are appropriate to achieve equivalent
program benefits.
(ii) NHTSA Program Phase-In 2016 and Later
    NHTSA is proposing to allow manufacturers to select one of two fuel
consumption standard alternatives for model years 2016 and later.
Manufacturers would select an alternative at the same time they submit
the model year 2016 Pre-Certification Compliance Report; and, once
selected, the alternative would apply for model years 2016 and later,
and could not be reversed. To meet the EISA statutory requirement for
three years of regulatory stability, the first alternative would define
a fuel consumption target line function for gasoline vehicles and a
target line function for diesel vehicles that would not change for
model years 2016 and later. The proposed target line function
coefficients are provided in Table II-8.
    The second alternative would be equivalent to the EPA target line
functions in each model year starting in 2016 and continuing
afterwards. Stringency of fuel consumption standards would increase
gradually for the 2016 and later model years. Relative to a model year
2010 unregulated baseline, for both gasoline and diesel vehicles,
stringency would be 40, 60, and 100 percent of the 2018 target line
function in model years 2016, 2017, and 2018, respectively.
    The stringency of the target line functions in the first
alternative for model years 2016-2017-2018-2019 is 67-67-67-100
percent, respectively, of the 2018 stringency in the second
alternative. The stringency of the first alternative was established so
that a manufacturer with a stable production volume and mix over the
model year 2016-2018 period, could use Averaging, Banking and Trading
to comply with

either alternative and have a similar credit balance at the end of
model year 2018 under the EPA and NHTSA programs.
    NHTSA also requests comment on a different regulatory approach that
would parallel the above-described EPA regulatory alternative involving
certification of a pre-defined percentage of a manufacturer's HD pickup
and van production.
(iii) NHTSA Voluntary Standards Period
    NHTSA is proposing that manufacturers may voluntarily opt into the
NHTSA HD pickup and van program in model years 2014 or 2015. If a
manufacturer elects to opt into the program, the program would become
mandatory and the manufacturer would not be allowed to reverse this
decision. To opt into the program, a manufacturer must declare its
intent to opt in to the program at the same time it submits the Pre-
Certification Compliance Report. See proposed regulatory text for 49
CFR 535.8 for information related to the Pre-Certification Compliance
Report. If a manufacturer elects to opt into the program in 2014, the
program would be mandatory for 2014 and 2015. A manufacturer would
begin tracking credits and debits beginning in the model year in which
they opt into the program. The handling of credits and debits would be
the same as for the mandatory program.
    For manufacturers that opt into NHTSA's HD pickup and van fuel
consumption program in 2014 or 2015, the stringency would increase
gradually each model year. Relative to a model year 2010 unregulated
baseline, for both gasoline and diesel vehicles, stringency would be
15-20 percent of the model year 2018 target line function (under the
NHTSA second alternative) in model years 2014-2015, respectively. The
corresponding absolute standards targets levels are provided in Figure
II-1 and II-2, and the accompanying equations.
    NHTSA also requests comment on a different regulatory approach that
would parallel the above-described EPA regulatory alternative involving
certification of a pre-defined percentage of a manufacturer's HD pickup
and van production.
(2) What are the proposed HD pickup and van test cycles and procedures?
    EPA and NHTSA are proposing that HD pickup and van testing be
conducted using the same heavy-duty chassis test procedures currently
used by EPA for measuring criteria pollutant emissions from these
vehicles, but with the addition of the highway fuel economy test cycle
(HFET) currently required only for light-duty vehicle GHG emissions and
fuel economy testing. Although the highway cycle driving pattern would
be identical to that of the light-duty test, other test parameters for
running the HFET, such as test vehicle loaded weight, would be
identical to those used in running the current EPA Federal Test
Procedure for complete heavy-duty vehicles.
    The GHG and fuel consumption results from vehicle testing on the
Light-duty FTP and the HFET would be weighted by 55 percent and 45
percent, respectively, and then averaged in calculating a combined
cycle result. This result corresponds with the data used to develop the
proposed work factor-based CO2 and fuel consumption
standards, since the data on the baseline and technology efficiency was
also developed in the context of these test procedures. The addition of
the HFET and the 55/45 cycle weightings are the same as for the light-
duty CO2 and CAFE programs, as we believe the real world
driving patterns for HD pickups and vans are not too unlike those of
light-duty trucks, and we are not aware of data specifically on these
patterns that would lead to a different choice of cycles and
weightings. More importantly, we believe that the 55/45 weightings will
provide for effective reductions of GHG emissions and fuel consumption
from these vehicles, and that other weightings, even if they were to
more precisely match real world patterns, are not likely to
significantly improve the program results.
    Another important parameter in ensuring a robust test program is
vehicle test weight. Current EPA testing for HD pickup and van criteria
pollutants is conducted with the vehicle loaded to its Adjusted Loaded
Vehicle Weight (ALVW), that is, its curb weight plus \1/2\ of the
payload capacity. This is substantially more challenging than loading
to the light-duty vehicle test condition of curb weight plus 300
pounds, but we believe that this loading for HD pickups and vans to \1/
2\ payload better fits their usage in the real world and would help
ensure that technologies meeting the standards do in fact provide real
world reductions. The choice is likewise consistent with use of an
attribute based in considerable part on payload for the standard. We
see no reason to set test load conditions differently for GHGs and fuel
consumption than for criteria pollutants, and we are not aware of any
new information (such as real world load patterns) since the ALVW was
originally set this way that would support a change in test loading
conditions. We are therefore proposing to use ALVW for test vehicle
loading in GHG and fuel consumption testing.
    EPA and NHTSA request comment on the proposed test cycles,
weighting factors, test loading conditions, and other factors that are
important for establishing an effective GHG and fuel consumption test
program. Additional provisions for our proposed testing and compliance
program are provided in Section V.B.
(3) How are the HD pickup and van standards structured?
    EPA and NHTSA are proposing fleet average standards for new HD
pickups and vans, based on a manufacturer's new vehicle fleet makeup.
In addition, EPA is proposing in-use standards that would apply to the
individual vehicles in this fleet over their useful lives. The
compliance provisions for these proposed fleet average and in-use
standards for HD pickups and vans are largely based on the recently
promulgated light-duty GHG and fuel economy program, as described below
and in greater detail in Section V.B. We request comment on any
compliance provisions we have taken from the light-duty program that
commenters feel would not be appropriate for HD pickups and vans or
that should be adjusted in some way to better regulate HD GHGs and fuel
consumption cost-effectively.
(a) Fleet Average Standards
    In this proposal we outline how each manufacturer would have a GHG
standard and a fuel consumption standard unique to its new HD pickup
and van fleet in each model year, depending on the load capacities of
the vehicle models produced by that manufacturer, and on the U.S.-
directed production volume of each of those models in that model year.
Vehicle models with larger payload/towing capacities would have
individual targets at numerically higher CO2 and fuel
consumption levels than lower payload/towing vehicles would, as
discussed in Section II.C(1). The fleet average standard for a
manufacturer would be a production-weighted average of the work factor-
based targets assigned to unique vehicle configurations within each
model type produced by the manufacturer in a model year.
    The fleet average standard with which the manufacturer must comply
would be based on its final production figures for the model year, and
thus a final assessment of compliance would occur after production for
the model year ended. Because compliance with the fleet average
standards depends on

actual test group production volumes, it is not possible to determine
compliance at the time the manufacturer applies for and receives an EPA
certificate of conformity for a test group. Instead, at certification
the manufacturer would demonstrate a level of performance for vehicles
in the test group, and make a good faith demonstration that its fleet,
regrouped by unique vehicle configurations within each model type, is
expected to comply with its fleet average standard when the model year
is over. EPA would issue a certificate for the vehicles covered by the
test group based on this demonstration, and would include a condition
in the certificate that if the manufacturer does not comply with the
fleet average, then production vehicles from that test group will be
treated as not covered by the certificate to the extent needed to bring
the manufacturer's fleet average into compliance. As in the light-duty
program, additional ``model type'' testing would be conducted by the
manufacturer over the course of the model year to supplement the
initial test group data. The emissions and fuel consumption levels of
the test vehicles would be used to calculate the production-weighted
fleet averages for the manufacturer, after application of the
appropriate deterioration factor to each result to obtain a full useful
life value. See generally 75 FR 25470-25472.
    EPA and NHTSA do not currently anticipate notable deterioration of
CO2 emissions and fuel consumption performance, and are
therefore proposing that an assigned deterioration factor be applied at
the time of certification: an additive assigned deterioration factor of
zero, or a multiplicative factor of one would be used. EPA and NHTSA
anticipate that the deterioration factor would be updated from time to
time, as new data regarding emissions deterioration for CO2
are obtained and analyzed. Additionally, EPA and NHTSA may consider
technology-specific deterioration factors, should data indicate that
certain control technologies deteriorate differently than others. See
also 75 FR 25474.
(b) In-Use Standards
    Section 202(a)(1) of the CAA specifies that EPA set emissions
standards that are applicable for the useful life of the vehicle. The
in-use standards that EPA is proposing would apply to individual
vehicles. NHTSA is not proposing to adopt in-use standards because it
is not required under EISA, and because it is not currently anticipated
that there will be any notable deterioration of fuel consumption. For
the EPA proposal, compliance with the in-use standard for individual
vehicles and vehicle models will not impact compliance with the fleet
average standard, which will be based on the production weighted
average of the new vehicles.
    EPA is proposing that the in-use standards for HD pickups and vans
be established by adding an adjustment factor to the full useful life
emissions and fuel consumption results used to calculate the fleet
average. EPA is also proposing that the useful life for these vehicles
with respect to GHG emissions be set equal to their useful life for
criteria pollutants: 11 years or 120,000 miles, whichever occurs first
(40 CFR 86.1805-04(a)).
    As discussed above, we are proposing that certification test
results obtained before and during the model year be used directly to
calculate the fleet average emissions for assessing compliance with the
fleet average standard. Therefore, this assessment and the fleet
average standard itself do not take into account test-to-test
variability and production variability that can affect measured in-use
levels. For this reason, EPA is proposing an adjustment factor for the
in-use standard to provide some margin for production and test-to-test
variability that could result in differences between the initial
emission test results used to calculate the fleet average and emission
results obtained during subsequent in-use testing. EPA is proposing
that each model's in-use CO2 standard would be the model-
specific level used in calculating the fleet average, plus 10 percent.
This is the same as the approach taken for light-duty vehicle GHG in-
use standards (See 75 FR 25473-25474).
    As it does now for heavy-duty vehicle criteria pollutants, EPA
would use a variety of mechanisms to conduct assessments of compliance
with the proposed in-use standards, including pre-production
certification and in-use monitoring once vehicles enter customer
service. The full useful life in-use standards would apply to vehicles
that had entered customer service. The same standards would apply to
vehicles used in pre-production and production line testing, except
that deterioration factors would not be applied.
(4) What HD pickup and van flexibility provisions are being proposed?
    This proposal contains substantial flexibility in how manufacturers
can choose to implement the EPA and NHTSA standards while preserving
their timely benefits for the environment and energy security. Primary
among these flexibilities are the gradual phase-in schedule,
alternative compliance paths, and corporate fleet average approach
described above. Additional flexibility provisions are described
briefly here and in more detail in Section IV.
    As explained in Section II.C(3), we are proposing that at the end
of each model year, when production for the model year is complete, a
manufacturer calculate its production-weighted fleet average
CO2 and fuel consumption. Under this proposed approach, a
manufacturer's HD pickup and van fleet that achieves a fleet average
CO2 or fuel consumption level better than its standard would
be allowed to generate credits. Conversely, if the fleet average
CO2 or fuel consumption level does not meet its standard,
the fleet would incur debits (also referred to as a shortfall).
    A manufacturer whose fleet generates credits in a given model year
would have several options for using those credits to offset emissions
from other HD pickups and vans. These options include credit carry-
back, credit carry-forward, and credit trading. These provisions exist
in the 2012-2016 MY light-duty vehicle National Program, and similar
provisions are part of EPA's Tier 2 program for light-duty vehicle
criteria pollutant emissions, as well as many other mobile source
standards issued by EPA under the CAA. The manufacturer would be able
to carry back credits to offset a deficit that had accrued in a prior
model year and was subsequently carried over to the current model year,
with a limitation on the carry-back of credits to three years,
consistent with the light-duty program. We are proposing that, after
satisfying any need to offset pre-existing deficits, a manufacturer may
bank remaining credits for use in future years. We are also proposing
that manufacturers may certify their HD pickup and van fleet a year
early, in MY 2013, to generate credits against the MY 2014 standards.
This averaging, banking, and trading program for HD pickups and vans is
discussed in more detail in Section IV.A. For reasons discussed in
detail in that section, we are not proposing any credit transferability
to or from other credit programs, such as the light-duty GHG and fuel
consumption programs or the proposed heavy-duty engine ABT program.
    Consistent with the President's May 21, 2010 directive to promote
advanced technology vehicles, we are proposing and seeking comment on
flexibility provisions that would parallel similar provisions adopted
in the light-duty program. These include credits for advance technology
vehicles such as electric vehicles, and credits for

innovative technologies that are shown by the manufacturer to provide
GHG and fuel consumption reductions in real world driving, but not on
the test cycle. See Section IV.B.
    We believe that it may also be appropriate to take steps to
recognize the benefits of flexible-fueled vehicles (FFVs) and dedicated
alternative-fueled vehicles based on the approach taken by EPA in the
light-duty vehicle rule for later models years (2016 and later).
However, unlike in that rule, we do not believe it is appropriate to
create a provision for additional credits similar to the 2012-2015
light-duty program because the HD sector does not have the incentives
mandated in EISA for light-duty vehicles. In fact, since heavy-duty
vehicles were not included in the EISA incentives for FFVs,
manufacturers have not in the past produced FFV heavy-duty vehicles. On
the other hand, we do seek comment on how to properly recognize the
impact of the use of alternative fuels, and E85 in particular, in HD
pickups and vans, including the proper accounting for alternative fuel
use in FFVs in the real world.\75\ As proposed, FFV performance would
be determined in the same way as for light-duty vehicles, with a 50-50
weighting of alternative and conventional fuel test results through MY
2015, and a manufacturer-determined weighting based on demonstrated
fuel use in the real world after MY 2015 (defaulting to an assumption
of 100 percent conventional fuel use). For dedicated alternative fueled
vehicles, NHTSA proposes that vehicles be tested with the alternative
fuel, and a petroleum equivalent fuel consumption level be calculated
based on the Petroleum Equivalency Factor (PEF) that is determined by
the Department of Energy. However, we are accepting comment on whether
to provide a flexibility program similar to the program we currently
offer for light-duty FFV vehicles.
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    \75\ E85 is a blended fuel consisting of nominally 15 percent
gasoline and 85 percent ethanol.
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D. Class 2b-8 Vocational Vehicles

    Class 2b-8 vocational vehicles consist of a very wide variety of
configurations including delivery, refuse, utility, dump, cement,
transit bus, shuttle bus, school bus, emergency vehicle, motor
homes,\76\ and tow trucks, among others. The agencies are defining that
Class 2b-8 vocational vehicles are all heavy-duty vehicles which are
not included in the Heavy-duty Pickup Truck and Van or the Class 7 and
8 Tractor categories, with the exception of vehicles for which the
agencies are deferring setting of standards, such as small business
manufacturers. In addition, recreational vehicles are included under
EPA's proposed standards but are not included under NHTSA's proposed
standards.
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    \76\ See above for discussion of applicability of NHTSA's
standards to non-commercial vehicles.
---------------------------------------------------------------------------

    As mentioned in Section I, vocational vehicles undergo a complex
build process. Often an incomplete chassis is built by a chassis
manufacturer with an engine purchased from an engine manufacturer and a
transmission purchased from another manufacturer. A body manufacturer
purchases an incomplete chassis which is then completed by attaching
the appropriate features to the chassis.
    The agencies face difficulties in establishing the baseline
CO2 and fuel consumption performance for the wide variety of
vocational vehicles which makes it difficult to try and set different
standards for a large number of potential regulatory categories. The
diversity in the vocational vehicle segment can be primarily attributed
to the variety of vehicle bodies rather than to the chassis. For
example, a body builder can build either a Class 6 bucket truck or a
Class 6 delivery truck from the same Class 6 chassis. The aerodynamic
difference between these two vehicles due to their bodies will lead to
different baseline fuel consumption and GHG emissions. However, the
baseline fuel consumption and emissions due to the components included
in the common chassis (such as the engine, drivetrain, frame, and
tires) will be the same between these two types of complete vehicles.
Furthermore, the agencies evaluated the aerodynamic improvement
opportunities for vocational vehicles. For example, the aerodynamics of
a fire truck are impacted significantly by the equipment such as
ladders located on the exterior of the truck. The agencies found little
opportunity to improve the aerodynamics of the equipment on the truck.
The agencies also evaluated the aerodynamic opportunities discussed in
the NAS report. The panel found that there was no fuel consumption
reduction opportunity through aerodynamic technologies for bucket
trucks, transit buses, and refuse trucks \77\ primarily due to the low
vehicle speed in normal operation. The panel did report that there are
opportunities to reduce the fuel consumption of straight trucks by
approximately 1 percent for trucks which operate at the average speed
typical of a pickup and delivery truck (30 mph), although the
opportunity is greater for trucks which operate at higher speeds.\78\
To overcome the lack of baseline information from the different vehicle
applications without sacrificing much fuel consumption or GHG emission
reduction potential, the agencies propose to set standards for the
chassis manufacturers of vocational vehicles (instead of the body
builders) and the engine manufacturers.
---------------------------------------------------------------------------

    \77\ See 2010 NAS Report, Note 19, page 133.
    \78\ See 2010 NAS Report, Note 19, page 110.
---------------------------------------------------------------------------

    EPA is proposing CO2 standards and NHTSA is proposing
fuel consumption standards for manufacturers of chassis for new
vocational vehicles and for manufacturers of heavy-duty engines
installed in these vehicles. The proposed heavy-duty engine standards
for CO2 emissions and fuel consumption would focus on
potential technological improvements in fuel combustion and overall
engine efficiency and those proposed controls would achieve most of the
emission reductions. Further reductions from the Class 2b-8 vocational
vehicle itself are possible within the timeframe of these proposed
regulations. Therefore, the agencies are also proposing separate
standards for vocational vehicles that will focus on additional
reductions that can be achieved through improvements in vehicle tires.
The agencies' analyses, as discussed briefly below and in more detail
later in this preamble and in the draft RIA Chapter 2, show that these
proposed standards appear appropriate under each agency's respective
statutory authorities. Together these standards are estimated to
achieve reductions of up to 11 percent from vocational vehicles.
    EPA is also proposing standards to control N2O and
CH4 emissions from Class 2b-8 vocational vehicles. The
proposed heavy-duty engine standards for both N2O and
CH4 and details of the standard are included in the
discussion in Section II. EPA is not proposing air conditioning leakage
standards applying to chassis manufacturers to address HFC emissions.
    As discussed further below, the agencies propose to set
CO2 and fuel consumption standards for these chassis based
on tire rolling resistance improvements and for the engines based on
engine technologies. The fuel consumption and GHG emissions impact of
tire rolling resistance is impacted by the mass of the vehicle. However
the impact of mass on rolling resistance is relatively small so the
agencies propose to aggregate several vehicle weight categories under a
single category for setting the standards. The agencies propose to
divide the vocational vehicle segment into three broad regulatory
categories--Light

Heavy-Duty (Class 2b through 5), Medium Heavy-Duty (Class 6 and 7), and
Heavy Heavy-Duty (Class 8) which is consistent with the nomenclature
used in the diesel engine classification. The agencies are interested
in comment on this segmentation strategy (subcategorization). As the
agencies move towards future heavy-duty fuel consumption and GHG
regulations for post-2017 model years, we intend to gather GHG and fuel
consumption data for specific vocational applications which could be
used to establish application-specific standards in the future.
(1) What are the proposed CO2 and fuel consumption standards
and their timing?
    In developing the proposed standards, the agencies have evaluated
the current levels of emissions and fuel consumption, the kinds of
technologies that could be utilized by manufacturers to reduce
emissions and fuel consumption and the associated lead time, the
associated costs for the industry, fuel savings for the consumer, and
the magnitude of the CO2 and fuel savings that may be
achieved. The technologies that the agencies considered while setting
the proposed vehicle-level standards include improvements in lower
rolling resistance tires. The technologies that the agencies considered
while setting the engine standards include engine friction reduction,
aftertreatment optimization, among others. The agencies' evaluation
indicates that these technologies are available today in the heavy-duty
tractor and light-duty vehicle markets, but have very low application
rates in the vocational market. The agencies have analyzed the
technical feasibility of achieving the proposed CO2 and fuel
consumption standards, based on projections of what actions
manufacturers would be expected to take to reduce emissions and fuel
consumption to achieve the standards, and believe that the proposed
standards are cost-effective and technologically feasible and
appropriate within the rulemaking time frame. EPA and NHTSA also
present the estimated costs and benefits of the proposed vocational
vehicle standards in Section III.
(a) Proposed Chassis Standards
    As shown in Table II-9, EPA is proposing the following
CO2 standards for the 2014 model year for the Class 2b
through Class 8 vocational vehicle chassis. Similarly, NHTSA is
proposing the following fuel consumption standards for the 2016 model
year, with voluntary standards beginning in the 2014 model year. For
the EPA GHG program, the proposed standard applies throughout the
useful life of the vehicle.
    EPA and NHTSA are proposing more stringent vehicle standards for
the 2017 model year which reflect the CO2 emissions
reductions required through the 2017 model year engine standards. As
explained in Section II. D. (2)(c)(iv) below, engine performance is one
of the inputs into the compliance model, and that input will change in
2017 to reflect the 2017 MY engine standards. The 2017 MY vehicle
standards are not premised on manufacturers installing additional
vehicle technologies.
[GRAPHIC] [TIFF OMITTED] TP30NO10.022

(i) Off-Road Vocational Vehicle Standards
    In developing  the proposal EPA and NHSTA received comment from
manufacturers and owners that certain vocational vehicles sometimes
have very limited on-road usage. These trucks are defined to be motor
vehicles under 40 CFR 85.1703, but they will spend the majority of
their operations off-road. Trucks, such as those used in oil fields,
will experience little benefit from low rolling resistance tires. The
agencies are therefore proposing to allow a narrow range of these de
facto off-road trucks to be excluded from the proposed vocational
vehicle standards because the trucks require special off-road tires
such as lug tires. The trucks must still use a certified engine, which
will provide fuel consumption and CO2 emission reductions to
the truck in all

applications. To insure that these trucks are in fact used chiefly off-
road, the agencies are proposing requirements that the vehicles have
off-road tires, have limited high speed operation, and are designed for
specific off-road applications. The agencies are specifically proposing
that a truck must meet the following requirements to qualify for an
exemption from the vocational vehicle standards:
---------------------------------------------------------------------------

    \79\ Manufacturers may voluntarily opt-in to the NHTSA fuel
consumption program in 2014 or 2015. If a manufacturer opts-in, the
program becomes mandatory.
---------------------------------------------------------------------------

     Installed tires which are lug tires or contain a speed
rating of less than or equal to 60 mph; and
     Include a vehicle speed limiter governed to 55 mph.
    EPA and NHTSA have concluded that the on-road performance losses
and additional costs to develop a truck which meets these
specifications will limit the exemption to trucks built for the desired
purposes. The agencies welcome comment on the proposed requirements and
exemptions.
(b) Proposed Heavy-duty Engine Standards
    EPA is proposing GHG standards \80\ and NHTSA is proposing fuel
consumption standards for new heavy-duty engines installed in
vocational vehicles. The standards will vary depending on whether the
engines are diesel or gasoline powered. The agencies' analyses, as
discussed briefly below and in more detail later in this preamble and
in the draft RIA Chapter 2, show that these standards are appropriate
and feasible under each agency's respective statutory authorities.
---------------------------------------------------------------------------

    \80\ Specifically, EPA is proposing CO2,
N2O, and CH4 emissions standards for new
heavy-duty engines over an EPA specified useful life period (see
Section II. E. for the N2O and CH4 standards).
---------------------------------------------------------------------------

    The agencies have analyzed the feasibility of achieving the GHG and
fuel consumption standards, based on projections of what actions
manufacturers are expected to take to reduce emissions and fuel
consumption. EPA and NHTSA also present the estimated costs and
benefits of the heavy-duty engine standards in Section III. In
developing the proposed rules, the agencies have evaluated the kinds of
technologies that could be utilized by engine manufacturers compared to
a baseline engine, as well as the associated costs for the industry and
fuel savings for the consumer and the magnitude of the GHG and fuel
consumption savings that may be achieved.
    With respect to the lead time and cost of incorporating technology
improvements that reduce GHG emissions and fuel consumption, the
agencies place important weight on the fact that during MYs 2014-2017,
engine manufacturers are expected to redesign and upgrade their
products only once. Over these four model years there will be an
opportunity for manufacturers to evaluate almost every one of their
engine models and add technology in a cost-effective way to control GHG
emissions and reduce fuel consumption. The time-frame and levels for
the standards, as well as the ability to average, bank and trade
credits and carry a deficit forward for a limited time, are expected to
provide manufacturers the time needed to incorporate technology that
will achieve the proposed GHG and fuel consumption reductions, and to
do this as part of the normal engine redesign process. This is an
important aspect of the proposed rules, as it will avoid the much
higher costs that would occur if manufacturers needed to add or change
technology at times other than these scheduled redesigns. This time
period will also provide manufacturers the opportunity to plan for
compliance using a multi-year time frame, again in accord with their
normal business practice. Further details on lead time, redesigns and
technical feasibility can be found in Section III.
    EPA's existing criteria pollutant emissions regulations for heavy-
duty highway engines establish four regulatory categories (three for
compression-ignition or diesel engines and one for spark ignition or
gasoline engines) that represent the engine's intended and primary
truck application, as shown in Table II-10 (40 CFR 1036.140). The
agencies welcome comments on the existing definition of the regulatory
categories (such as typical horsepower levels) as described in 40 CFR
1036.140. All heavy-duty engines are covered either under the heavy-
duty pickup truck and van category or under the heavy-duty engine
standards.
[GRAPHIC] [TIFF OMITTED] TP30NO10.023

    For the purposes of the GHG engine emissions and engine fuel
consumption standards that EPA and NHTSA are proposing, the agencies
intend to maintain these same four regulatory subcategories for GHG
engine emissions standards and fuel consumption standards. This
category structure would enable the agencies to set standards that
appropriately reflect the technology available for engines for use in
each type of vehicle.
(i) Diesel Engine Standards
    EPA's proposed heavy-duty diesel engine CO2 emission
standards are presented in Table II-11. Similar to EPA's non-GHG
standards approach, manufacturers may generate and use credits to show
compliance with the standards. The EPA standards become effective in
2014 model year, with more stringent standards becoming effective in
model year 2017. Recently, EPA's

non-GHG heavy-duty engine program provided new emissions standards for
the industry in three year increments. Largely, the heavy-duty engine
and truck manufacturer product plans have fallen into three year cycles
to reflect this environment. The proposed two-step CO2
emission standards recognize the opportunity for technology
improvements over this timeframe while reflecting the typical diesel
truck manufacturer product plan cycles.
    NHTSA's fuel consumption standards, also presented in Table II-11,
would contain voluntary engine standards starting in 2014 model year,
with mandatory engine standards starting in 2017 model year,
synchronizing with EPA's 2017 model year standards. A manufacturer may
opt-in to NHTSA's voluntary standards in 2014, 2015 or 2016. Once a
manufacturer opts-in, the standards become mandatory for the opt-in and
subsequent model years, and the manufacturer may not reverse its
decision. To opt into the program, a manufacture must declare its
intent to opt in to the program with documented communication of the
intent, at the same time it submits the Pre-Certification Compliance
Report. See 49 CFR 535.8 for information related to the Pre-
Certification Compliance Report. A manufacturer opting into the program
would begin tracking credits and debits beginning in the model year in
which they opt into the program.
    The agencies are proposing the same standard level for the Light
Heavy and Medium Heavy diesel engine categories. The agencies found
that there is an overlap in the displacement of engines which are
currently certified as LHDD or MHDD. The agencies developed the
baseline 2010 model year CO2 emissions from data provided to
EPA by the manufacturers during the non-GHG certification process.
Analysis of CO2 emissions from 2010 model year LHD and MHDD
diesel engines showed little difference between LHD and MHD diesel
engine baseline CO2 performance, which overall averaged 630
g CO2/bhp-hr (6.19 gal/100 bhp-hr),\81\ in the 2010 model
year. Furthermore, the technologies available to reduce fuel
consumption and CO2 emissions from these two categories of
engines are similar. The agencies are proposing to maintain these two
separate engine categories with the same standard level (instead of
combining them into a single category) to respect the different useful
life periods associated with each category. The agencies are proposing
to evaluate compliance with the LHD/MHD diesel engine standards based
on the Heavy-duty FTP cycle.
---------------------------------------------------------------------------

    \81\ Calculated using the conversion 10,180 g CO2/
gallon for diesel fuel.
---------------------------------------------------------------------------

    The agencies found a difference in the baseline 2010 model year
CO2 and fuel consumption performance between the LHD/MHD
diesel engines, which averaged 630 g CO2/bhp-hr (6.19 gal/
100 bhp-hr),\82\ and the HHD diesel engines, which averaged 584 g
CO2/bhp-hr (5.74 gal/100 bhp-hr). The HHD diesel engine data
is also based on manufacturer submitted CO2 data for non-GHG
emissions certification process. In addition, the agencies believe that
there may be some technologies available to reduce fuel consumption and
CO2 emissions that may not be appropriate for both the LHD/
MHD diesel and the HHD diesel engines, such as turbocompounding.
Therefore, the agencies are proposing a standard level for HHD diesel
engines which differs from the LHD/MHD diesel engine standard level
likewise to be evaluated on the Heavy-duty FTP cycle.
---------------------------------------------------------------------------

    \82\ Calculated using the conversion 10,180 g CO2/
gallon for diesel fuel.
---------------------------------------------------------------------------

    We are proposing standards based on the Heavy-duty FTP cycle for
engines used in vocational vehicles reflecting their primary use in
transient operating conditions typified by both frequent accelerations
and decelerations as well as some steady cruise conditions as
represented on the Heavy-duty FTP. The primary reason the agencies are
proposing to set two separate HHD diesel engine standards--one for HHD
diesel engines used in tractors and the other for HHD diesel engines
used in vocational vehicles--is to encourage engine manufacturers to
install technologies appropriate to the intended use of the engine with
the vehicle. Tractors spend the majority of their operation at steady
state conditions, and will obtain in-use benefit of technologies such
as turbocompounding and other waste heat recovery technologies during
this kind of typical engine operation. Therefore, the engines installed
in line haul tractors would be required to meet the standard based on
the SET, which is a steady state test cycle. On the other hand,
vocational vehicles such as urban delivery trucks spend more time
operating in transient conditions and may not realize the benefit of
this type of technology in-use. The use of the Heavy-duty FTP for these
engines would focus engine design on technologies that realize in-use
benefits during the kind of operation typical for these engines.
Therefore, we are proposing that engines installed in vocational
vehicles be required to meet the standard and demonstrate compliance
over the transient Heavy-duty FTP cycle. The levels of the standards
reflect the difference in baseline emissions for the different test
procedures.
    As noted in Section II.B above, the engine standards that EPA is
proposing and the voluntary standards being proposed by NHTSA for the
2014 model year would require diesel engine manufacturers to achieve on
average a three percent reduction in fuel consumption and
CO2 emissions over the baseline 2010 model year performance
for the HHD diesel engines and a five percent reduction for the LHD and
MHD diesel engines. The agencies' assessment of the NAS report and
other literature sources indicates that there are technologies
available to reduce fuel consumption by this level in the proposed
timeframe in a cost-effective manner. These technologies include
improved turbochargers, aftertreatment optimization, low temperature
exhaust gas recirculation, and engine friction reductions. Additional
discussion on technical feasibility is included in Section III below
and in draft RIA Chapter 2.
    Additionally, the agencies are proposing that diesel engines
further reduce fuel consumption and CO2 emissions in the
2017 model year. The proposed 2017 model year standards for the LHD and
MHD diesel engines represent a 9 percent reduction from the 2010 model
year. The proposed reductions represent on average a five percent
decrease over the 2010 baseline for HHD diesel engines required to test
compliance using the Heavy-duty FTP test cycle. The additional
reductions may be achieved through the increased development of the
technologies evaluated for the 2014 model year standard. See draft RIA
Chapter 2. The agencies' analysis indicates that this type of advanced
engine development will require a longer development time than the 2014
model year and therefore are proposing to provide additional lead time
to allow for its introduction.
    Similar to EPA's non-GHG standards approach, manufacturers may
generate and use credits by the same engine subcategory to show
compliance with both agencies' standards.

[GRAPHIC] [TIFF OMITTED] TP30NO10.024

    In proposing these standards for diesel engines used in vocational
vehicles, the agencies have looked primarily at the typical performance
levels of the majority of engines in the fleet. As explained above in
Section II.B, we also recognize that when regulating a category of
products for the first time, there will be individual products that may
deviate from this baseline level of performance. Recognizing that for
these products a reduction from the industry baseline may be more
costly than the agencies have assumed or perhaps even not feasible in
the lead time available for these standards, EPA and NHTSA are
proposing a regulatory alternative whereby a manufacturer could comply
with a unique standard based on a five percent reduction from the
products own 2011 baseline level. Our assessment is that this five
percent reduction is appropriate and technologically feasible given the
manufacturers' ability to apply similar technology packages with
similar cost to what we have estimated for the primary program. For
this purpose, the agencies do not see that potential obstacles are
greater or lesser for engine standards which are based on the SET
procedure or Heavy-duty FTP cycle. We do not believe this alternative
needs to continue past 2016 since manufacturers will have had ample
opportunity to benchmark competitive products and make appropriate
changes to bring their product performance into line with the rest of
the industry.
    However, we are requesting comment on the potential to extend this
regulatory alternative for one additional year for a single engine
family with performance measured in that year as nine percent beyond
the engine's own 2011 model year baseline level. We also request
comment on the level of reduction beyond the baseline that is
appropriate in this alternative. The five percent level reflects the
aggregate improvement beyond the baseline we are requiring of the
entire industry. As this provision is intended to address potential
issues for legacy products that we would expect to be replaced or
significantly improved at the manufacturer's next product change, we
request comment if a two percent reduction would be more appropriate.
We would consider two percent rather than five percent if we were
convinced that making all of the changes we have outlined in our
assessment of the technical feasibility of the standards was not
possible for some engines due to legacy design issues that will change
in the next design cycle. We are proposing that manufacturers making
use of these provisions would need to exhaust all credits within this
subcategory prior to using this flexibility and would not be able to
generate emissions credits from other engines in the same regulatory
subcategory as the engines complying using this alternate approach.
(ii) Gasoline Engine Standard
    Heavy-duty gasoline engines are also used in vocational vehicle
applications. The number of engines certified in the past for this
segment of vehicles is very limited and has ranged between three and
five engine models. Unlike the purpose-built heavy-duty diesel engines
typical of this segment, these gasoline engines are developed for
heavy-duty pickup trucks and vans primarily, but are also sold as loose
engines to vocational vehicle manufacturers. Therefore, the agencies
evaluated these engines in parallel with the heavy-duty pickup truck
and van standard development. As with the pickup truck and van segment,
the agencies anticipate that the manufacturers will have only one
engine re-design within the 2014-18 model years under consideration
within this proposal. In our meetings with all three of the major
manufacturers in this segment, confidential future product plans were
shared with the agencies. Reflecting those plans and our estimates for
when engine changes will be made in alignment with those product plans,
we have concluded that the 2016 model year reflects the most logical
model year start date for the heavy-duty gasoline engine standards. In
order to meet the standards we are proposing for heavy-duty pickups and
vans, we project that all manufacturers will have redesigned their
gasoline engine offerings by the start of the 2016 model year. Given
the small volume of loose gasoline engine sales relative to complete
heavy-duty pickup sales, we think it is appropriate to set the timing
for the heavy-duty gasoline engine standard in line with our
projections for engine redesigns to meet the heavy-duty pickup truck
standards. Therefore, NHTSA's proposed fuel consumption standard and
EPA's proposed CO2 standard for heavy-duty gasoline engines
are first effective in the 2016 model year.
    The baseline 2010 model year CO2 performance of these
heavy-duty gasoline engines over the Heavy-duty FTP cycle is 660 g
CO2/bhp-hr (6.48 gal/100 bhp-hr) in 2010 based on non-GHG
certification data provided to EPA by the manufacturers. The agencies
propose that manufacturers achieve a five percent reduction in
CO2 in the 2016 model year over the 2010 MY baseline through
use of technologies such as coupled cam phasing, engine friction
reduction, and stoichiometric gasoline direct injection. Additional
detail on technology feasibility is included in Section III and in the
draft RIA Chapter 2.
    NHTSA is proposing a 7.05 gallon/100 bhp-hr standard for fuel
consumption while EPA is proposing a 627 g CO2/bhp-hr
standard tested over the Heavy-duty FTP, effective in the 2016 model
year. Similar to EPA's non-GHG standards approach, manufacturers may
generate and use credits by the same engine subcategory to show
compliance with both agencies' standards.
    In the preceding section on diesel engines, we describe an
alternative compliance approach for diesel engines based on
improvements from an engine's own baseline of performance. We are not
making a similar proposal for gasoline engines, but we request comment
on the need for and appropriateness of such an approach. Comments
suggesting the need for a

similar approach should include specific recommendations on how the
approach would work and the technical reasons why such an approach
would be necessary in order to make the gasoline engine standards
feasible.
(c) In-Use Standards
    Section 202(a)(1) of the CAA specifies that emissions standards are
to be applicable for the useful life of the vehicle. The in-use
standards that EPA is proposing would apply to individual vehicles and
engines. NHTSA is not proposing to adopt in-use standards that would
apply to the vehicles and engines in a similar fashion.
    EPA is proposing that the in-use standards for heavy-duty engines
installed in vocational vehicles be established by adding an adjustment
factor to the full useful life emissions and fuel consumption results.
EPA is proposing a 2 percent adjustment factor for the in-use standard
to provide some margin for production and test-to-test variability that
could result in differences between the initial emission test results
and emission results obtained during subsequent in-use testing.
    EPA is proposing that the useful life for these engine and vehicles
with respect to GHG emissions be set equal to the respective useful
life periods for criteria pollutants. EPA proposes that the existing
engine useful life periods, as included in Table II-12, be broadened to
include CO2 emissions and fuel consumption for both engines
and tractors (see 40 CFR 86.004-2). While NHTSA proposes to use useful
life considerations for establishing fuel consumption performance for
initial compliance and for ABT, NHTSA does not intend to implement an
in-use compliance program for fuel consumption, because it is not
required under EISA and because it is not currently anticipated there
will be notable deterioration of fuel consumption over the engines'
useful life.
[GRAPHIC] [TIFF OMITTED] TP30NO10.025

    EPA requests comments on the magnitude and need for an in-use
adjustment factor for the engine standard and the compliance model GEM,
based chassis standard.
(2) Test Procedures and Related Issues
    The agencies are proposing test procedures to evaluate fuel
consumption and CO2 emissions of vocational vehicles in a manner very
similar to Class 7 and Class 8 combination tractors. This section
describes a simulation model for demonstrating compliance, engine test
procedures, and a test procedure for evaluating hybrid powertrains (a
potential means of generating credits, although not part of the
technology on which the proposed standard is premised).
(a) Computer Simulation Model
    As previously mentioned, to achieve the goal of reducing emissions
and fuel consumption for both trucks and engines, we are proposing to
set separate engine and vehicle-based emission standards. For the
vocational vehicles, engine manufacturers would be subject to the
engine standards, and chassis manufacturers would be required to
install certified engines in their chassis. The chassis manufacturer
would be subject to a separate vehicle-based standard that would use
the proposed truck simulation model to evaluate the impact of the tire
design to determine compliance with the truck standard.
    A simulation model, in general, uses various inputs to characterize
a vehicle's properties (such as weight, aerodynamics, and rolling
resistance) and predicts how the vehicle would behave on the road when
it follows a driving cycle (vehicle speed versus time). On a second-by-
second basis, the model determines how much engine power needs to be
generated for the vehicle to follow the driving cycle as closely as
possible. The engine power is then transmitted to the wheels through
transmission, driveline, and axles to move the vehicle according to the
driving cycle. The second-by-second fuel consumption of the vehicle,
which corresponds to the engine power demand to move the vehicle, is
then calculated according to the fuel consumption map embedded in the
compliance model. Similar to a chassis dynamometer test, the second-by-
second fuel consumption is aggregated over the complete drive cycle to
determine the fuel consumption of the vehicle.
    NHTSA and EPA are proposing to evaluate fuel consumption and
CO2 emissions respectively through a simulation of whole-
vehicle operation, consistent with the NAS recommendation to use a
truck model to evaluate truck performance. The agencies developed the
GEM for the specific purpose of this proposal to evaluate truck
performance. The GEM is similar in concept to a number of vehicle
simulation tools developed by commercial and government entities. The
model developed by the agencies and proposed here was designed for the
express purpose of vehicle compliance demonstration and is therefore
simpler and less configurable than similar commercial products. This
approach gives a compact and quicker tool for evaluating vehicle
compliance without the overhead and costs of a more complicated model.
Details of the model are included in Chapter 4 of the draft RIA.
    GEM is designed to focus on the inputs most closely associated with
fuel consumption and CO2 emissions--i.e., on those which
have the largest impacts such as aerodynamics, rolling resistance,
weight, and others.
    EPA and NHTSA have validated GEM based on the chassis test results
from three SmartWay certified tractors tested at Southwest Research
Institute. The validation work conducted on these three vehicles is
representative of the other Class 7 and 8 tractors. Many

aspects of one tractor configuration (such as the engine, transmission,
axle configuration, tire sizes, and control systems) are similar to
those used on the manufacturer's sister models. For example, the
powertrain configuration of a sleeper cab is similar to the one used on
a straight truck. Details of the validation testing and its
representativeness are included in draft RIA Chapter 4. Overall, the
GEM predicted the fuel consumption and CO2 emissions within
4 percent of the chassis test procedure results for three test cycles--
the California ARB Transient cycle, the California ARB High Speed
Cruise cycle, and the Low Speed Cruise cycle. These cycles are very
similar to the ones the agencies are proposing to utilize in compliance
testing. Test to test variation for heavy-duty vehicle chassis testing
can be higher than 4 percent based on driver variation. The proposed
simulation model is described in greater detail in draft RIA Chapter 4
and is available for download by interested parties at (http://
www.epa.gov/otaq/). We request comment on all aspects of this approach
to compliance determination in general and to the use of the GEM in
particular.
    The agencies are proposing that for demonstrating compliance, a
chassis manufacturer would measure the performance of tires, input the
values into GEM, and compare the model's output to the standard. Tires
are the only technology on which the agencies' own feasibility analysis
for these vehicles is predicated. An example of the GEM input screen is
included in Figure II-3. The input values for the simulation model
would be derived by the manufacturer from tire test procedure proposed
by the agencies in this proposal. The agencies are proposing that the
remaining model inputs would be fixed values that are pre-defined by
the agencies and are detailed in the draft RIA Chapter 4, including the
engine fuel consumption map to be used in the simulation.
[GRAPHIC] [TIFF OMITTED] TP30NO10.026

(b)Tire Rolling Resistance Assessment
    As with the Class 7 and 8 combination tractors, NHTSA and EPA are
proposing that the vocational vehicle's tire rolling resistance input
to the GEM be determined using the ISO 28580:2009 test method.\83\ The
agencies believe the ISO test procedure is appropriate to propose for
this program because the procedure is the same one used by the NHTSA
tire fuel efficiency labeling program \84\ and is consistent with the
direction being taken by the tire industry both in the United States
and Europe, and with the EPA SmartWay program. The rolling resistance
from this test would be used to specify the rolling resistance of each
tire on the steer and drive axle of the vehicle. The results would be
expressed as a rolling resistance coefficient and measured as kilogram
per ton (kg/metric ton). The agencies are proposing that three tire
samples within each tire model be tested three times each to account
for some of the production variability and the average of the three
tests would be the rolling resistance coefficient for the tire.
---------------------------------------------------------------------------

    \83\ ISO, 2009, Passenger Car, Truck, and Bus Tyres--Methods of
Measuring Rolling Resistance--Single Point Test and Correlation of
Measurement Results: ISO 28580:2009(E), First Edition, 2009-07-01.
    \84\ NHTSA, 2009. ``NHTSA Tire Fuel Efficiency Consumer
Information Program Development: Phase 1--Evaluation of Laboratory
Test Protocols.'' DOT HS 811 119. June. (http://www.regulations.gov,
Docket ID: NHTSA-2008-0121-0019).
---------------------------------------------------------------------------

(c)Defined Vehicle Configurations in the GEM
    As discussed above, the agencies are proposing a methodology that
chassis manufacturers would use to quantify the tire rolling resistance
values to be input into the GEM. Moreover, the agencies are proposing
to define the remaining

GEM inputs (i.e., specify them by rule), which may differ by the
regulatory subcategory (for reasons described in the draft RIA). The
defined inputs being proposed include the drive cycle, aerodynamics,
truck curb weight, payload, engine characteristics, and drivetrain for
each vehicle type, among others.
(i) Metric
    Based on NAS's recommendation and feedback from the heavy-duty
truck industry, NHTSA and EPA are proposing standards for vocational
vehicles that would be expressed in terms of moving a ton of payload
over one mile. Thus, NHTSA's proposed fuel consumption standards for
these trucks would be represented as gallons of fuel used to move one
ton of payload one thousand miles, or gal/1,000 ton-mile. EPA's
proposed CO2 vehicle standards would be represented as grams
of CO2 per ton-mile.
(ii) Drive cycle
    The drive cycle being proposed for the vocational vehicles consists
of the same three modes proposed for the Class 7-8 combination
tractors. The agencies are thus proposing the use of the Transient
mode, as defined by California ARB in the HHDDT cycle, a constant speed
cycle at 65 mph and a 55 mph constant speed mode. However, we are
proposing different weightings for each mode than proposed for Class 7
and 87 and 8 combination tractors, given the known difference in
driving patterns between these two categories of vehicles. (The same
reasoning underlies the agencies' proposal to use the Heavy-duty FTP
cycle to evaluate compliance with the standards for diesel engines used
in vocational vehicles.)
    The variety of vocational vehicle applications makes it challenging
to establish a single cycle which is representative of all such trucks.
However, in aggregate, the vocational vehicles typically operate over
shorter distances and spend less time cruising at highway speeds than
combination tractors. The agencies evaluated two sources for mode
weightings, as detailed in draft RIA Chapter 3. The agencies are
proposing the mode weightings based on the vehicle speed
characteristics of single unit trucks used in EPA's MOVES model which
were developed using Federal Highway Administration data to distribute
vehicle miles traveled by road type.\85\ The proposed weighted
CO2 and fuel consumption value consists of 37 percent of 65
mph Cruise, 21 percent of 55 mph Cruise, and 42 percent of Transient
performance, which are reflected in the GEM.
---------------------------------------------------------------------------

    \85\ The Environmental Protection Agency. Draft MOVES2009
Highway Vehicle Population and Activity Data. EPA-420-P-09-001,
August 2009 http://www.epa.gov/otaq/models/moves/techdocs/
420p09001.pdf.
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(iii) Empty Weight and Payload
    The total weight of the vehicle is the sum of the tractor curb
weight and the payload. The agencies are proposing to specify each of
these aspects of the vehicle. The agencies developed the truck curb
weight inputs based on industry information developed by ICF.\86\ The
proposed curb weights are 10,300 pounds for the LH trucks, 13,950
pounds for the MH trucks, and 29,000 pounds for the HH trucks.
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    \86\ ICF International. ``Investigation of Costs for Strategies
to Reduce Greenhouse Gas Emissions for Heavy-Duty On-Road
Vehicles.'' July 2010. Pages 16-20. Docket ID EPA-HQ-OAR-
2010-0162-0044.
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    NHTSA and EPA are also proposing the following payload requirement
for each regulatory category. The payloads were developed from Federal
Highway statistics based on averaging the payloads for the weight
categories represented within each vehicle subcategory.\87\ The
proposed payload requirement is 5,700 pounds for the Light Heavy-Duty
trucks, 11,200 pounds for Medium Heavy-Duty trucks, and 38,000 pounds
for Heavy Heavy-Duty trucks. Additional information is available in
draft RIA Chapter 3.
---------------------------------------------------------------------------

    \87\ The U.S. Federal Highway Administration. Development of
Truck Payload Equivalent Factor. Table 11. Last viewed on March 9,
2010 at http://ops.fhwa.dot.gov/freight/freight_analysis/faf/faf2_
reports/reports9/s510_11_12_tables.htm.
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(iv) Engine
    As the agencies are proposing separate engine and truck standards,
the GEM will be used to assess the compliance of the chassis with the
vehicle standard. To maintain the separate assessments, the agencies
are proposing to use fixed values that are pre-defined by the agencies
for the engine characteristics used in GEM, including the fuel
consumption map which provides the fuel consumption at hundreds of
engine speed and torque points. If the agencies did not standardize the
fuel map, then a truck that uses an engine with emissions and fuel
consumption better than the standards would require fewer vehicle
reductions than those being proposed. The agencies are proposing that
the engine characteristics used in GEM be representative of a diesel
engine, because it represents the largest fraction of engines in this
market.
    The agencies are proposing two distinct sets of fuel consumption
maps for use in GEM. The first fuel consumption map would be used in
GEM for the 2014 through 2016 model years and represent a diesel engine
which meets the 2014 model year engine CO2 emissions
standards. A second fuel consumption map would be used beginning in the
2017 model year and represents a diesel engine which meets the 2017
model year CO2 emissions and fuel consumption standards and
accounts for the increased stringency in the proposed MY 2017
standard). Effectively there is no change in stringency of the
vocational vehicle standard (not including the engine) so that there is
stability in the vocational vehicle (not including engine) standards
for the full rulemaking period. These inputs are reasonable (indeed,
seemingly necessitated) given the separate proposed regulatory
requirement that vocational vehicle chassis manufacturers use only
certified engines.
(v) Drivetrain
    The agencies' assessment of the current vehicle configuration
process at the truck dealer's level is that the truck companies provide
software tools to specify the proper drivetrain matched to the buyer's
specific circumstances. These dealer tools allow a significant amount
of customization for drive cycle and payload to provide the best
specification for the customer. The agencies are not seeking to disrupt
this process. Optimal drivetrain selection is dependent on the engine,
drive cycle (including vehicle speed and road grade), and payload. Each
combination of engine, drive cycle, and payload has a single optimal
transmission and final drive ratio. The agencies are proposing to
specify the engine's fuel consumption map, drive cycle, and payload;
therefore, it makes sense to specify the drivetrain that matches.
    In conclusion, for vocational vehicles, compliance would be
determined by establishing values for the tire rolling resistance and
using the prescribed inputs in GEM. The model would produce
CO2 and fuel consumption results that would be compared
against EPA's and NHTSA's respective standards.
(d) Engine Test Procedures
    The NAS panel did not specifically discuss or recommend a metric to
evaluate the fuel consumption of heavy-duty engines. However, as noted
above they did recommend the use of a load-specific fuel consumption
metric for the

evaluation of vehicles.\88\ An analogous metric for engines would be
the amount of fuel consumed per unit of work. Thus, EPA is proposing
that GHG emission standards for engines under the CAA would be
expressed as g/bhp-hr: similarly, NHTSA's proposed fuel consumption
standards under EISA would be represented as gallons of fuel per 100
horsepower-hour (gal/100 bhp-hr). EPA's metric is also consistent with
EPA's current standards for non-GHG emissions for these engines.
---------------------------------------------------------------------------

    \88\ See 2010 NAS Report, Note 19, page 39.
---------------------------------------------------------------------------

    EPA's criteria pollutant standards for engines currently require
that manufacturers demonstrate compliance over the transient FTP cycle;
over the steady-state SET procedure; and during not-to-exceed testing.
EPA created this multi-layered approach to criteria emissions control
in response to engine designs that optimized operation for lowest fuel
consumption at the expense of very high criteria emissions when
operated off the regulatory cycle. EPA's use of multiple test
procedures for criteria pollutants helps to ensure that manufacturers
calibrate engine systems for compliance under all operating conditions.
With regard to GHG and fuel consumption control, the agencies believe
it is more appropriate to set standards based on a single test
procedure, either the Heavy-duty FTP or SET, depending on the primary
expected use of the engine.
    As discussed above, it is critical to set standards based on the
most representative test cycles in order for performance in-use to
obtain the intended (and feasible) air quality benefits. We further
explained why the Heavy-duty FTP is the appropriate test cycle for
engines used in vocational vehicles, and the steady-state SET procedure
the most appropriate for engines used in combination tractors. We are
not concerned if off-cycle manufacturers further calibrate these
designs to give better in-use fuel consumption while maintaining
compliance with the criteria emissions standards as such calibration is
entirely consistent with the goals of our joint program. Further, we
believe that setting standards based on both transient and steady-state
operating conditions for all engines could lead to undesirable
outcomes. For example, as noted earlier, turbocompounding is one
technology that the agencies have identified as a likely approach for
compliance with our proposed HHD SET standard described below.
Turbocompounding is a very effective approach to lower fuel consumption
under steady driving conditions typified by combination tractor trailer
operation and is well reflected in testing over the SET test procedure.
However, when used in driving typified by transient operation as we
expect for vocational vehicles and as is represented by the Heavy-duty
FTP, turbocompounding shows very little benefit. Setting an emission
standard based on the Heavy-duty FTP for engines intended for use in
combination tractor trailers could lead manufacturers to not apply
turbocompounding even though it can be a highly cost effective means to
reduce GHG emissions and lower fuel consumption.
    The current non-GHG emissions engine test procedures also require
the development of regeneration emission rates and frequency factors to
account for the emission changes during a regeneration event (40 CFR
86.004-28). EPA and NHTSA are proposing to exclude the CO2
emissions and fuel consumption increases due to regeneration from the
calculation of the compliance levels over the defined test procedures.
We considered including regeneration in the estimate of fuel
consumption and GHG emissions and have decided not to do so for two
reasons. First, EPA's existing criteria emission regulations already
provide a strong motivation to engine manufacturers to reduce the
frequency and duration of infrequent regeneration events. The very
stringent 2010 NOX emission standards cannot be met by
engine designs that lead to frequent and extended regeneration events.
Hence, we believe engine manufacturers are already reducing
regeneration emissions to the greatest degree possible. In addition to
believing that regenerations are already controlled to the extent
technologically possible, we believe that attempting to include
regeneration emissions in the standard setting could lead to an
inadvertently lax emissions standard. In order to include regeneration
and set appropriate standards, EPA and NHTSA would have needed to
project the regeneration frequency and duration of future engine
designs in the timeframe of this proposal. Such a projection would be
inherently difficult to make and quite likely would underestimate the
progress engine manufacturers will make in reducing infrequent
regenerations. If we underestimated that progress, we would effectively
be setting a more lax set of standards than otherwise would be
expected. Hence in setting a standard including regeneration emissions
we faced the real possibility that we would achieve less effective
CO2 emissions control and fuel consumption reductions than
we will achieve by not including regeneration emissions. We are seeking
comments regarding regeneration emissions and what approach if any the
agencies should use in reflecting regeneration emissions in this
program.
(e) Hybrid Powertrain Technology
    Although the proposed vocational vehicle standards are not premised
on use of hybrid powertrains, certain vocational vehicle applications
may be suitable candidates for use of hybrids due to the greater
frequency of stop-and-go urban operation and their use of power take-
off (PTO) systems. Examples are vocational vehicles used predominantly
in stop-start urban driving (e.g., delivery trucks). As an incentive,
the agencies are proposing to provide credits for the use of hybrid
powertrain technology as described in Section IV. The agencies are
proposing that any credits generated using such technologies could be
applied to any heavy-duty vehicle or engine, and not be limited to the
vehicle category generating the credit. Section IV below also details
the proposed approach to account for the use of a hybrid powertrain
when evaluating compliance with the truck standard. In general,
manufacturers can derive the fuel consumption and CO2
emissions reductions based on comparative test results using the
proposed chassis testing procedures. We are proposing the same three
drive cycles and cycle weightings discussed for the vocational vehicles
to evaluate trucks that use hybrid powertrains to power the vehicle
during motive operation (such as pickup and delivery trucks and transit
buses). However, we are proposing an additional PTO test cycle for
trucks which use a PTO to power equipment while the vehicle is either
idling or moving (such as bucket or refuse trucks). The reductions due
to the hybrid technology would be calculated relative to the same type
of vehicle with a conventional powertrain tested using the same
protocol.
(3) Summary of Proposed Flexibility and Credit Provisions
    EPA and NHTSA are proposing a number of flexibility provisions for
vocational vehicle chassis manufacturers and engine manufacturers, as
discussed in Section IV below. These provisions are all based on an
averaging, banking and trading program for emissions and fuel
consumption credits. They include provisions to encourage the
introduction of advanced technologies such as hybrid drivetrains,
provisions to

incentivize early compliance with the proposed standards, and
provisions to allow compliance using innovative technologies
unanticipated by the agencies in developing this proposal.
(4) Deferral of Standards for Small Chassis Manufacturing and Small
Engine Companies
    EPA and NHTSA are proposing to defer greenhouse gas emissions and
fuel consumption standards from small vocational vehicle chassis
manufacturers meeting the SBA size criteria of a small business as
described in 13 CFR 121.201 (see 40 CFR 1036.150 and 1037.150). The
agencies will instead consider appropriate GHG and fuel consumption
standards for these entities as part of a future regulatory action.
This includes both U.S.-based and foreign small volume heavy-duty truck
and engine manufacturers.
    The agencies have identified ten chassis entities that appear to
fit the SBA size criterion of a small business.\89\ The agencies
estimate that these small entities comprise less than 0.5 percent of
the total heavy-duty vocational vehicle market in the United States
based on Polk Registration Data from 2003 through 2007,\90\ and
therefore that the exemption will have a negligible impact on the GHG
emissions and fuel consumption improvements from the proposed
standards.
---------------------------------------------------------------------------

    \89\ The agencies have identified Lodal, Indiana Phoenix,
Autocar LLC, HME, Giradin, Azure Dynamics, DesignLine International,
Ebus, Krystal Koach, and Millenium Transit Services LLC as potential
small business chassis manufacturers.
    \90\ M.J. Bradley. Heavy-duty Vehicle Market Analysis. May 2009.
---------------------------------------------------------------------------

    EPA and NHTSA have also identified three engine manufacturing
entities that appear to fit the SBA size criteria of a small business
based on company information included in Hoover's.\91\ Based on 2008
and 2009 model year engine certification data submitted to EPA for non-
GHG emissions standards, the agencies estimate that these small
entities comprise less than 0.1 percent of the total heavy-duty engine
sales in the United States. The proposed exemption from the standards
established under this proposal would have a negligible impact on the
GHG emissions and fuel consumption reductions otherwise due to the
standards.
---------------------------------------------------------------------------

    \91\ The agencies have identified Baytech Corporation, Clean
Fuels USA, and BAF Technologies, Inc. as three potential small
businesses.
---------------------------------------------------------------------------

    To ensure that the agencies are aware of which companies would be
exempt, we propose to require that such entities submit a declaration
to EPA and NHTSA containing a detailed written description of how that
manufacturer qualifies as a small entity under the provisions of 13 CFR
121.201.

E. Other Standards Provisions

    In addition to proposing CO2 emission standards for
heavy-duty vehicles and engines, EPA is also proposing separate
standards for N2O and CH4 emissions.\92\ NHTSA is
not proposing comparable separate standards for these GHGs because they
are not directly related to fuel consumption in the same way that
CO2 is, and NHTSA's authority under EISA exclusively relates
to fuel efficiency. N2O and CH4 are important
GHGs that contribute to global warming, more so than CO2 for
the same amount of emissions due to their high Global Warming Potential
(GWP).\93\ EPA is proposing N2O and CH4 standards
which apply to HD pickup trucks and vans as well as to all heavy-duty
engines. EPA is not proposing N2O and CH4
standards for the Class 7 and 8 tractor or Class 2b-8 chassis
manufacturers because these emissions would be controlled through the
engine program.
---------------------------------------------------------------------------

    \92\ NHTSA's statutory responsibilities relating to reducing
fuel consumption are directly related to reducing CO2
emissions, but not to the control of other GHGs.
    \93\ N2O has a GWP of 298 and CH4 has a
GWP of 25 according to the IPCC Fourth Assessment Report.
---------------------------------------------------------------------------

    EPA is requesting comment in Section II.E.4 below on possible
alternative CO2 equivalent approaches to provide near-term
flexibility for 2012-14 MY light-duty vehicles.
    Almost universally across current engine designs, both gasoline-
and diesel-fueled, N2O and CH4 emissions are
relatively low today and EPA does not believe it would be appropriate
or feasible to require reductions from the levels of current gasoline
and diesel engines. This is because for the most part, the same
hardware and controls used by heavy-duty engines and vehicles that have
been optimized for nonmethane hydrocarbon (NMHC) and NOX
control indirectly result in highly effective control of N2O
and CH4. Additionally, unlike criteria pollutants, specific
technologies beyond those presently implemented in heavy-duty vehicles
to meet existing emission requirements have not surfaced that
specifically target reductions in N2O or CH4.
Because of this, reductions in N2O or CH4 beyond
current levels in most heavy-duty applications would occur through the
same mechanisms that result in NMHC and NOX reductions and
would likely result in an increase in the overall stringency of the
criteria pollutant emission standards. Nevertheless, it is important
that future engine technologies or fuels not currently researched do
not result in increases in these emissions, and this is the intent of
the proposed ``cap'' standards. The proposed standards would act to cap
emissions at today's levels to ensure that manufacturers maintain
effective N2O and CH4 emissions controls
currently used should they choose a different technology path from what
is currently used to control NMHC and NOX but also largely
successful methods for controlling N2O and CH4.
As discussed below, some technologies that manufacturers may adopt for
reasons other than reducing fuel consumption or GHG emissions could
increase N2O and CH4 emissions if manufacturers
do not address these emissions in their overall engine and
aftertreatment design and development plans. Manufacturers will be able
to design and develop the engines and aftertreatment to avoid such
emissions increases through appropriate emission control technology
selections like those already used and available today. Because EPA
believes that these standards can be capped at the same level,
regardless of type of HD engine involved, the following discussion
relates to all types of HD engines regardless of the vehicles in which
such engines are ultimately used. In addition, since these standards
are designed to cap current emissions, EPA is proposing the same
standards for all of the model years to which the rules apply.
    EPA believes that the proposed N2O and CH4
cap standards would accomplish the primary goal of deterring increases
in these emissions as engine and aftertreatment technologies evolve
because manufacturers will continue to target current or lower
N2O and CH4 levels in order to maintain typical
compliance margins. While the cap standards are set at levels that are
higher than current average emission levels, the control technologies
used today are highly effective and there is no reason to believe that
emissions will slip to levels close to the cap, particularly
considering compliance margin targets. The caps will protect against
significant increases in emissions due to new or poorly implemented
technologies. However, we also believe that an alternative compliance
approach that allows manufacturers to convert these emissions to
CO2eq emission values and combine them with CO2
into a single compliance value would also be appropriate, so long as it
did not undermine the stringency of the CO2 standard. As
described below, EPA is proposing that such an alternative

compliance approach be available to manufacturers to provide certain
flexibilities for different technologies.
    EPA requests comments on the approach to regulating N2O
and CH4 emissions including the appropriateness of ``cap''
standards, the technical bases for the levels of the proposed
N2O and CH4 standards, the proposed test
procedures, and the proposed timing for the standards. In addition, EPA
seeks any additional emissions data on N2O and
CH4 from current technology engines.
    EPA is basing its proposed N2O and CH4
standards on available test data. We are soliciting additional data,
and especially data for in-use vehicles and engines that would help to
better characterize changes in emissions of these pollutants throughout
their useful lives, for both gasoline and diesel applications. As is
typical for EPA emissions standards, we are proposing that
manufacturers should establish deterioration factors to ensure
compliance throughout the useful life. We are not at this time aware of
deterioration mechanisms for N2O and CH4 that
would result in large deterioration factors, but neither do we believe
enough is known about these mechanisms to justify proposing assigned
factors corresponding to no deterioration, as we are proposing for
CO2, or for that matter to any predetermined level. We are
therefore asking for comment on this subject.
    In addition to N2O and CH4 standards, this
section also discusses air conditioning-related provisions and EPA's
proposal to extend certification requirements to all-electric HD
vehicles and vehicles and engines designed to run on ethanol fuel.
(1) What is EPA's proposed approach to controlling N2O?
    N2O is a global warming gas with a GWP of 298. It
accounts for about 0.3% of the current greenhouse gas emissions from
heavy-duty trucks.\94\
---------------------------------------------------------------------------

    \94\ Value adapted from ``Inventory of U.S. Greenhouse Gas
Emissions and Sinks: 1990-2007. April 2009.
---------------------------------------------------------------------------

    N2O is emitted from gasoline and diesel vehicles mainly
during specific catalyst temperature conditions conducive to
N2O formation. Specifically, N2O can be generated
during periods of emission hardware warm-up when rising catalyst
temperatures pass through the temperature window when N2O
formation potential is possible. For current heavy-duty gasoline
engines with conventional three-way catalyst technology, N2O
is not generally produced in significant amounts because the time the
catalyst spends at the critical temperatures during warm-up is short.
This is largely due to the need to quickly reach the higher
temperatures necessary for high catalyst efficiency to achieve emission
compliance of criteria pollutants. N2O formation is
generally only a concern with diesel and potentially with future
gasoline lean-burn engines with compromised NOX emissions
control systems. If the risk for N2O formation is not
factored into the design of the controls, these systems can but need
not be designed in a way that emphasizes efficient NOX
control while allowing the formation of significant quantities of
N2O. However, these future advanced gasoline and diesel
technologies do not inherently require N2O formation to
properly control NOX. Pathways exist today that meet
criteria emission standards that would not compromise N2O
emissions in future systems as observed in current production engine
and vehicle testing \95\ which would also work for future diesel and
gasoline technologies. Manufacturers would need to use appropriate
technologies and temperature controls during future development
programs with the objective to optimize for both NOX and
N2O control. Therefore, future designs and controls at
reducing criteria emissions would need to take into account the balance
of reducing these emissions with the different control approaches while
also preventing inadvertent N2O formation, much like the
path taken in current heavy-duty compliant engines and vehicles.
Alternatively, manufacturers who find technologies that reduce criteria
or CO2 emissions but see increases N2O emissions
beyond the cap could choose to offset N2O emissions with
reduction in CO2 as allowed in the proposed CO2eq
option discussed in Section II.E.3.
---------------------------------------------------------------------------

    \95\ Memorandum ``N2O Data from EPA Heavy-Duty
Testing''.
---------------------------------------------------------------------------

    EPA is proposing an N2O emission standard that we
believe would be met by current-technology gasoline and diesel vehicles
at essentially no cost. EPA believes that heavy-duty emission standards
since 2008 model year, specifically the very stringent NOX
standards for both engine and chassis certified engines, directly
result in stringent N2O control. It is believed that the
current emission control technologies used to meet the stringent
NOX standards achieve the maximum feasible reductions and
that no additional technologies are recognized that would result in
additional N2O reductions. As noted, N2O
formation in current catalyst systems occurs, but their emission levels
are inherently low, because the time the catalyst spends at the
critical temperatures during warm-up when N2O can form is
short. At the same time, we believe that the proposed standard would
ensure that the design of advanced NOX control systems for
future diesel and lean-burn gasoline vehicles would control
N2O emission levels. While current NOX control
approaches used on current heavy-duty diesel vehicles do not compromise
N2O emissions and actually result in N2O control,
we believe that the proposed standards would discourage any new
emission control designs for diesels or lean-burn gasoline vehicles
that achieve criteria emissions compliance at the cost of increased
N2O emissions. Thus, the proposed standard would cap
N2O emission levels, with the expectation that current
gasoline and diesel vehicle control approaches that comply with heavy-
duty vehicle emission standards for NOX would not increase
their emission levels, and that the cap would ensure that future diesel
and lean-burn gasoline vehicles with advanced NOX controls
would appropriately control their emissions of N2O.
(a) Heavy-Duty Pickup Truck and Van N2O Exhaust Emission
Standard
    EPA is proposing a per-vehicle N2O emission standard of
0.05 g/mi, measured over the Light-duty FTP and HFET drive cycles.
Similar to the CO2 standard approach, the N2O
emission level of a vehicle would be a composite of the Light-duty FTP
and HFET cycles with the same 55 percent city weighting and 45 percent
highway weighting. The standard would become effective in model year
2014 for all HD pickups and vans that are subject to the proposed
CO2 emission requirements. Averaging between vehicles would
not be allowed. The standard is designed to prevent increases in
N2O emissions from current levels, i.e., a no-backsliding
standard.
    The proposed N2O level is approximately two times the
average N2O level of current gasoline and diesel heavy-duty
trucks that meet the NOX standards effective since 2008
model year.\96\ Manufacturers typically use design targets for
NOX emission levels at approximately 50% of the standard, to
account for in-use emissions deterioration and normal testing and
production variability, and we expect manufacturers to utilize a
similar approach for N2O emission compliance. We are not
proposing a more stringent

standard for current gasoline and diesel vehicles because the stringent
heavy-duty NOX standards already result in significant
N2O control, and we do not expect current N2O levels to rise
for these vehicles particularly with expected manufacturer compliance
margins.
---------------------------------------------------------------------------

    \96\ Memorandum ``N2O Data from EPA Heavy-Duty
Testing''.
---------------------------------------------------------------------------

    Diesel heavy-duty pickup trucks and vans with advanced emission
control technology are in the early stages of development and
commercialization. As this segment of the vehicle market develops, the
proposed N2O standard would require manufacturers to
incorporate control strategies that minimize N2O formation.
Available approaches include using electronic controls to limit
catalyst conditions that might favor N2O formation and
considering different catalyst formulations. While some of these
approaches may have associated costs, EPA believes that they will be
small compared to the overall costs of the advanced NOX
control technologies already required to meet heavy-duty standards.
    The light-duty GHG rule requires that manufacturers begin testing
for N2O by 2015 model year. The manufacturers of complete
pickup trucks and vans (Ford, General Motors, and Chrysler) are already
impacted by the light-duty GHG rule and will therefore have this
equipment and capability in place for the timing of this proposal.
    Overall, we believe that manufacturers of HD pickups and vans (both
gasoline and diesel) would meet the proposed standard without
implementing any significantly new technologies, only further
refinement of their existing controls, and we do not expect there to be
any significant costs associated with this standard.
(b) Heavy-Duty Engine N2O Exhaust Emission Standard
    EPA is also proposing a per engine N2O emissions
standard of 0.05 g/bhp-hr for heavy-duty engines which become effective
in 2014 model year. These standards remain the same over the useful
life of the engine. The N2O emissions would be measured over
the Heavy-duty FTP cycle because it is believed that this cycle poses
the highest risk for N2O formation versus the additional
heavy-duty compliance cycles. Averaging between vehicles would not be
allowed. The standard is designed to prevent increases in
N2O emissions from current levels, i.e., a no-backsliding
standard.
    The proposed N2O level is twice the average
N2O level of current diesel engines as demonstrated in the
ACES Study and in EPA's testing of two additional engines with
selective catalytic reduction aftertreatement systems.\97\
Manufacturers typically use design targets for NOX emission
levels of about 50% of the standard, to account for in-use emissions
deterioration and normal testing and production variability, and
manufacturers are expected to utilize a similar approach for
N2O emission compliance. EPA requests comment on the
agency's technical assessment of current and potential future
N2O formation in heavy-duty engines, as presented here.
---------------------------------------------------------------------------

    \97\ Coordinating Research Council Report: ACES Phase 1 of the
Advanced Collaborative Emissions Study, 2009. (This study included
detailed chemical characterization of exhaust species emitted from
four 2007 model year heavy heavy diesel engines.)
---------------------------------------------------------------------------

    Engine emissions regulations do not currently require testing for
N2O. The Mandatory GHG Reporting final rule requires
reporting of N2O and requires that manufacturers either
measure N2O or use a compliance statement based on good
engineering judgment in lieu of direct N2O measurement (74
FR 56260, October 30, 2009). The light-duty GHG final rule allows
manufacturers to provide a compliance statement based on good
engineering judgment through the 2014 model year, but requires
measurement beginning in 2015 model year (75 FR 25324, May 7, 2010).
EPA is proposing a consistent approach for heavy-duty engine
manufacturers which allows them to delay direct measurement of
N2O until the 2015 model year. EPA welcomes comments on
whether there are differences in the heavy-duty market which would
warrant a different approach.
    Manufacturers without the capability to measure N2O by
the 2015 model year would need to acquire and install appropriate
measurement equipment in response to this proposed program. EPA has
established four separate N2O measurement methods, all of
which are commercially available today. EPA expects that most
manufacturers would use photo-acoustic measurement equipment, which EPA
estimates would result in a one-time cost of about $50,000 for each
test cell that would need to be upgraded.
    Overall, EPA believes that manufacturers of heavy-duty engines,
both gasoline and diesel, would meet the proposed standard without
implementing any new technologies, and beyond relatively small
facilities costs for any companies that still need to acquire and
install N2O measurement equipment, EPA does not project that
manufacturers would incur significant costs associated with this
proposed N2O standard.
    EPA is not proposing any vehicle-level N2O standards for
heavy-duty trucks (combination and vocational) in this proposal. The
N2O emissions would be controlled through the heavy-duty
engine portion of the program. The only requirement of those truck
manufacturers to comply with the N2O requirements is to
install a certified engine.
(2) What is EPA's proposed approach to controlling CH4?
    CH4 is greenhouse gas with a GWP of 25. It accounts for
about 0.03% of the greenhouse gases from heavy-duty trucks.\98\
---------------------------------------------------------------------------

    \98\ Value adapted from ``Inventory of U.S. Greenhouse Gas
Emissions and Sinks: 1990-2007. April 2009.
---------------------------------------------------------------------------

    EPA is proposing a standard that would cap CH4 emission
levels, with the expectation that current heavy-duty vehicles and
engines meeting the heavy-duty emission standards would not increase
their levels as explained earlier due to robust current controls and
manufacturer compliance margin targets. It would ensure that emissions
would be addressed if in the future there are increases in the use of
natural gas or any other alternative fuel. EPA believes that current
heavy-duty emission standards, specifically the NMHC standards for both
engine and chassis certified engines directly result in stringent
CH4 control. It is believed that the current emission
control technologies used to meet the stringent NMHC standards achieve
the maximum feasible reductions and that no additional technologies are
recognized that would result in additional CH4 reductions.
The level of the standard would generally be achievable through normal
emission control methods already required to meet heavy-duty emission
standards for hydrocarbons and EPA is therefore not attributing any
cost to this part of the proposal. Since CH4 is produced in
gasoline and diesel engines similar to other hydrocarbon components,
controls targeted at reducing overall NMHC levels generally also work
at reducing CH4 emissions. Therefore, for gasoline and
diesel vehicles, the heavy-duty hydrocarbon standards will generally
prevent increases in CH4 emissions levels. CH4
from heavy-duty vehicles is relatively low compared to other GHGs
largely due to the high effectiveness of the current heavy-duty
standards in controlling overall HC emissions.
    EPA believes that this level for the standard would be met by
current gasoline and diesel trucks and vans, and would prevent
increases in future CH4

emissions in the event that alternative fueled vehicles with high
methane emissions, like some past dedicated compressed natural gas
vehicles, become a significant part of the vehicle fleet. Currently EPA
does not have separate CH4 standards because, unlike other
hydrocarbons, CH4 does not contribute significantly to ozone
formation.\99\ However, CH4 emissions levels in the gasoline
and diesel heavy-duty truck fleet have nevertheless generally been
controlled by the heavy-duty HC emission standards. Even so, without an
emission standard for CH4, future emission levels of
CH4 cannot be guaranteed to remain at current levels as
vehicle technologies and fuels evolve.
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    \99\ But see Ford Motor Co. v. EPA, 604 F. 2d 685 (DC Cir. 1979)
(permissible for EPA to regulate CH4 under CAA section
202(b)).
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    In recent model years, a small number of heavy-duty trucks and
engines were sold that were designed for dedicated use of natural gas.
While emission control designs on these recent dedicated natural gas-
fueled vehicles demonstrate CH4 control can be as effective
as gasoline or diesel equivalent vehicles, natural gas-fueled vehicles
have historically produced significantly higher CH4
emissions than gasoline or diesel vehicles. This is because the fuel is
predominantly methane, and most of the unburned fuel that escapes
combustion without being oxidized by the catalyst is emitted as
methane. However, even if these vehicles meet the heavy-duty
hydrocarbon standard and appear to have effective CH4
control by nature of the hydrocarbon controls, the heavy-duty standards
do not require CH4 control and therefore some natural gas
vehicle manufacturers have invested very little effort into methane
control. While the proposed CH4 cap standard should not
require any different emission control designs beyond what is already
required to meet heavy-duty hydrocarbon standards on a dedicated
natural gas vehicle (i.e., feedback controlled 3-way catalyst), the cap
will ensure that systems provide robust control of methane much like a
gasoline-fueled engine. We are not proposing more stringent
CH4 standards because we believe that the controls used to
meet current heavy-duty hydrocarbon standards should result in
effective CH4 control when properly implemented. Since
CH4 is already measured under the current heavy-duty
emissions regulations (so that it may be subtracted to calculate NMHC),
the proposed standard would not result in additional testing costs. EPA
requests comment on whether the proposed cap standard would result in
any significant technological challenges for manufacturers of natural
gas vehicles.
(a) Heavy-Duty Pickup Truck and Van CH4 Standard
    EPA is proposing a CH4 emission standard of 0. 05 g/mi
as measured on the Light-duty FTP and HFET drive cycles, to apply
beginning with model year 2014 for HD pickups and vans subject to the
proposed CO2 standards. Similar to the CO2
standard approach, the CH4 emission level of a vehicle would
be a composite of the Light-duty FTP and HFET cycles with the same 55%
city weighting and 45% highway weighting.
    The level of the proposed standard is approximately two times the
average heavy-duty gasoline and diesel truck and van levels.\100\ As
with N2O, this proposed level recognizes that manufacturers
typically set emissions design targets with a compliance margin of
approximately 50% of the standard. Thus, we believe that the proposed
standard should be met by current gasoline vehicles with no increase
from today's CH4 levels. Similarly, since current diesel
vehicles generally have even lower CH4 emissions than
gasoline vehicles, we believe that diesels would also meet the proposed
standard with a larger compliance margin resulting in no change in
today's CH4 levels.
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    \100\ Memorandum ``CH4 Data from 2010 and 2011 Heavy-
Duty Vehicle Certification Tests''.
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(b) Heavy-Duty Engine CH4 Exhaust Emission Standard
    EPA is proposing a heavy-duty engine CH4 emission
standard of 0.05 g/hp-hr as measured on the Heavy-duty FTP, to apply
beginning in model year 2014. The proposed standard would cap
CH4 emissions at a level currently achieved by diesel and
gasoline heavy-duty engines. The level of the standard would generally
be achievable through normal emission control methods already required
to meet 2007 emission standards for NMHC and EPA is therefore not
attributing any cost to this part of this proposal (see 40 CFR 86.007-
11).
    The level of the proposed CH4 standard is twice the
average CH4 emissions from the four diesel engines in the
ACES study.\101\ As with N2O, this proposed level recognizes
that manufacturers typically set emission design targets at about 50%
of the standard. Thus, EPA believes the proposed standard would be met
by current diesel and gasoline engines with little if any technological
improvements. The agency believes a more stringent CH4
standard is not necessary due to effective CH4 controls in
current heavy-duty technologies, since, as discussed above for
N2O, EPA believes that the challenge of complying with the
CO2 standards should be the primary focus of the
manufacturers.
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    \101\ Coordinating Researth Council Report: ACES Phase 1 of the
Advanced Collaborative Emissions Study, 2009.
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    CH4 is measured under the current 2007 regulations so
that it may be subtracted to calculate NMHC. Therefore EPA expects that
the proposed standard would not result in additional testing costs.
    EPA is not proposing any vehicle-level CH4 standards for
heavy-duty trucks (combination or vocational) in this proposal. The
CH4 emissions would be controlled through the heavy-duty
engine portion of the program. The only requirement of these truck
manufacturers to comply with the CH4 requirements is to
install a certified engine.
(3) Alternative CO2 Equivalent Option
    If a manufacturer is unable to meet the N2O or
CH4 cap standards, EPA is proposing that the manufacturer
may choose to comply using CO2 credits. In other words, a
manufacturer could offset any N2O emissions or any
CH4 emissions by taking steps to further reduce
CO2. A manufacturer choosing this option would convert its
measured N2O and CH4 test results in excess of
the applicable standards into CO2eq to determine the amount
of CO2 credits required. For example, a manufacturer would
use 25 Mg of positive CO2 credits to offset 1 Mg of negative
CH4 credits or use 298 Mg of positive CO2 credits
to offset 1 Mg of negative N2O credits.\102\ By using the
Global Warming Potential of N2O and CH4, the
proposed approach recognizes the inter-correlation of these elements in
impacting global warming and is environmentally neutral to meeting the
proposed individual emissions caps.
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    \102\ N2O has a GWP of 298 and CH4 has a
GWP of 25 according to the IPCC Fourth Assessment Report.
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    The proposed NHTSA fuel consumption program will not use
CO2eq, as suggested above. Measured performance to the NHTSA
fuel consumption standards will be based on the measurement of
CO2 with no adjustment for N2O and/or
CH4. For manufacturers that use the EPA alternative
CO2eq credit, compliance to the EPA CO2 standard
will not be directly equivalent to compliance to the NHTSA fuel
consumption standard.

(4) Light-Duty Vehicle N2O and CH4 Standards
    For light-duty vehicles, as part of the MY 2012-2016 rulemaking,
EPA finalized standards for N2O and CH4 which
take effect with MY 2012. 75 FR at 25421-24. Similar to the heavy-duty
standards discussed in Section II.E above, the light-duty vehicle
standards for N2O and CH4 were established to cap
emissions and prevent future emissions increases, and were generally
not expected to result in the application of new technologies for
current vehicle designs or significant costs for the manufacturers. EPA
also finalized an alternative CO2 equivalent standard
option, which manufacturers may choose to use in lieu of complying with
the otherwise-applicable N2O and CH4 standards.
The CO2-equivalent standard option allows manufacturers to
fold all N2O and CH4 emissions, on a
CO2-equivalent basis, along with CO2 into their
otherwise applicable CO2 emissions standard level. For
flexible-fueled vehicles, the N2O and CH4
standards must be met on both fuels (e.g., both gasoline and E-85).
    EPA has learned since the standards were finalized that some
manufacturers may have difficulty meeting the N2O and/or
CH4 standards in the early years of the program for a few of
the vehicle models in their existing fleet. This is problematic in the
near-term because there is little lead time to implement unplanned
redesigns of vehicles to meet the standards. In such cases,
manufacturers may need to either drop vehicle models from their fleet
or to comply using the CO2 equivalent alternative. On a
CO2 equivalent basis, folding in all N2O and
CH4 emissions would add 3-4 g/mile or more to a
manufacturer's overall fleet-average CO2 emissions level
because the alternative standard must be used for the entire fleet, not
just for the problem vehicles. This could be especially challenging in
the early years of the program for manufacturers with little compliance
margin because there is very limited lead time to develop strategies to
address these additional emissions. EPA believes this poses a
legitimate issue of sufficiency of lead time in the short term (as well
as an issue of cost, since EPA assumed that the N2O and
CH4 standards were essentially cost free) but expects that
manufacturers would be able to make technology changes (e.g.,
calibration or catalyst changes) to the few vehicle models not
currently meeting the N2O and/or CH4 standards in
the course of their planned vehicle redesign schedules in order to meet
the standards.
    Because EPA intended for these standards to be caps with little
anticipated near-term impact on manufacturer's current product lines,
EPA believes that it would be appropriate to provide additional
flexibility in the near-term to allow manufacturers to meet the
N2O and CH4 standards. EPA requests comments on
the option of allowing manufacturers to use the CO2
equivalent approach for one pollutant but not the other for their
fleet--that is, allowing a manufacturer to fold in either
CH4 or N2O as part of the CO2-
equivalent standard. For example, if a manufacturer is having trouble
complying with the CH4 standard but not the N2O
standard, the manufacturer could use the N2O equivalent
option including CH4, but choose to comply separately with
the applicable N2O cap standard. EPA requests comments on
allowing this approach in the light-duty program for MYs 2012-2014 as
an additional flexibility to help manufacturers address any near-term
issues that they may have with the N2O and CH4
standards.
    EPA also requests comments on possible alternative approaches of
providing additional near-term flexibility. For example, as discussed
in Section II.E above, EPA is proposing for HD vehicles and engines to
allow manufacturers to use CO2 credits, on a CO2
equivalent basis, to offset N2O and CH4 emissions
above the applicable standard. EPA requests comment on whether this
approach would be appropriate for the light-duty program as an
additional flexibility. Again, the additional flexibility would be
limited to MYs 2012-2014 for the reasons discussed above. EPA notes
that, after considering all relevant comments, provisions to address
this issue may be finalized in an action independent of the heavy-duty
rulemaking process in the interest of finalizing the provisions as soon
as possible to provide manufacturers with certainty for MY 2012 light-
duty vehicles.
(5) EPA's Proposed Standards for Direct Emissions From Air Conditioning
    Air conditioning systems contribute to GHG emissions in two ways--
direct emissions through refrigerant leakage and indirect exhaust
emissions due to the extra load on the vehicle's engine to provide
power to the air conditioning system. HFC refrigerants, which are
powerful GHG pollutants, can leak from the A/C system.\103\ This
includes the direct leakage of refrigerant as well as the subsequent
leakage associate with maintenance and servicing, and with disposal at
the end of the vehicle's life.\104\ The most commonly used refrigerant
in automotive applications--R134a, has a high GWP of 1430.\105\ Due to
the high GWP of R134a, a small leakage of the refrigerant has a much
greater global warming impact than a similar amount of emissions of
CO2 or other mobile source GHGs.
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    \103\ The United States has submitted a proposal to the Montreal
Protocol which, if adopted, would phase-out production and
consumption of HFCs.
    \104\ The U.S. EPA has reclamation requirements for refrigerants
in place under Title VI of the Clean Air Act.
    \105\ The global warming potentials used in the NPRM analysis
are consistent with Intergovernmental Panel on Climate Change (IPCC)
Fourth Assessment Report. At this time, the global warming potential
values from the IPCC Second Assessment Report have been agreed upon
as the official U.S. framework for addressing climate change. The
global warming potential values from the IPCC Second Assessment
Report are used in the official U.S. greenhouse gas inventory
submission to the climate change framework. When inventories are
recalculated for the final rule, changes in global warming potential
may lead to adjustments.
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    Heavy-duty air conditioning systems today are similar to those used
in light-duty applications. However, differences may exist in terms of
cooling capacity (such that sleeper cabs have larger cabin volumes than
day cabs), system layout (such as the number of evaporators), and the
durability requirements due to longer truck life. However, the
component technologies and costs to reduce direct HFC emissions are
similar between the two types of vehicles.
    The quantity of GHG refrigerant emissions from heavy-duty trucks
relative to the CO2 emissions from driving the vehicle and
moving freight is very small. Therefore, a credit approach is not
appropriate for this segment of vehicles because the value of the
credit is too small to provide sufficient incentive to utilize feasible
and cost-effective air conditioning leakage improvements. For the same
reason, including air conditioning leakage improvements within the main
standard would in many instances result in lost control opportunities.
Therefore, EPA is proposing that truck manufacturers be required to
meet a low leakage requirement for all air conditioning systems
installed in 2014 model year and later trucks, with one exception. The
agency is not proposing leakage standards for Class 2b-8 Vocational
Vehicles at this time due to the complexity in the build process and
the potential for different entities besides the chassis manufacturer
to be involved in the air conditioning system production and
installation, with consequent difficulties in developing a regulatory
system.
    EPA is proposing a leakage standard which is a ``percent
refrigerant leakage

per year'' to assure that high-quality, low-leakage components are used
in each air conditioning system design. The agency believes that a
single ``gram of refrigerant leakage per year'' would not fairly
address the variety of air conditioning system designs and layouts
found in the heavy-duty truck sector. EPA is proposing a standard of
1.50 percent leakage per year for Heavy-duty Pickup Trucks and Vans and
Class 7 and 87 and 8 Tractors. The proposed standard was derived from
the vehicles with the largest system refrigerant capacity based on the
Minnesota GHG Reporting database.\106\ The average percent leakage per
year of the 2010 model year vehicles is 2.7 percent. This proposed
level of reduction is roughly comparable to that necessary to generate
credits under the light-duty vehicle program. See 75 FR 25426-25427.
Since refrigerant leakage past the compressor shaft seal is the
dominant source of leakage in belt-driven air conditioning systems, the
agency is seeking comment on whether the stringency of a single
``percent refrigerant leakage per year'' standard fairly addresses the