manufacturers passing forward deficits before reconciling their
shortfalls and exhausting those credits before reconciling past
deficits. Manufacturers of vehicles that generate a deficit at the end
of the model year could carry that deficit forward for three years
following the model year for which that deficit was generated. Deficits
would need to be reconciled at the reporting dates for year three. We
will accept comments on alternative approaches of reconciling deficit
shortfalls.
    Additional flexibilities for Class 7 and 8 combination tractors are
discussed later in Section IV.B.
(3) Class 2b-8 Vocational Vehicles
    Similar to the Class 7 and 8 combination tractor manufacturers, we
are offering a limited ABT program for Class 2b-8 vocational chassis
manufacturers. Vehicle credits would be generated for those
manufacturers that introduce products into the market with rolling
resistance improvements which are better than required to meet the
proposed vehicle standards, The certification of the chassis would be
based on the use of LRR tires. Credit calculation for the proposed
Class 2b-8 vocational vehicle CO2 and fuel consumption
credits (deficits) would be generated, either positive or negative,
according to Equation IV-5 and Equation IV-6:

Equation IV-5: The proposed Vocational Vehicle CO2 vehicle
credit (deficit)

Vocational Vehicle CO2 credit (deficit) (metric tons) =
(Std-FEL) x

(Payload Tons) x (Sales Volume) x (UL) x (10-6)

Where:

Std = the standard associated with the specific vocational vehicle
subcategory (g/ton-mile)
Payload tons = the prescribed payload for each subcategory in tons
(2.85 tons for LHD, 5.6 tons for MHD, and 19 tons for HHD vehicles)
FEL = Family Emission Limit for the vehicle family (g/ton-mile)
Volume = (projected or actual) production volume of the vehicle
family
UL = useful life of the vehicle (110,000 miles for LHD, 185,000
miles for MHD, or 435,000 miles for HHD vehicles)
10-6 converts the grams of CO2 to metric tons

Equation IV-6: Proposed Vocational Vehicle Fuel Consumption credit
(deficit) in gallons

Vocational Vehicle Fuel Consumption credit for (deficit) (gallons) =
(Std-FEL) x (Payload Tons) x (Sales Volume) x (UL) x 103

Where:

Std = the standard associated with the specific vocational vehicle
regulatory subcategory (gallon/1,000 ton-mile)
Payload tons = the prescribed payload for each regulatory
subcategory in tons (2.85 tons for LHD, 5.6 tons for MHD, and 19
tons for HHD vehicles)
FEL = Family Emission Limit for the vehicle family (gallon/1,000
ton-mile)
Volume = (projected or actual) production volume of the vehicle
family
UL = useful life of the vehicle (110,000 miles for LHD, 185,000
miles for MHD, or 435,000 miles for HHD vehicles)
10\3\ converts to gallons

    Also, similar to the proposed heavy-duty engine and tractor ABT
programs, the vehicle credits generated within each regulatory
subcategory would be allowed to be averaged, banked, or traded between
chassis manufacturers within their existing subcategories. For
vocational vehicles the proposed vehicle subcategories are based on the
vehicle's GVWR. We are proposing three vehicle subcategories LHD with a
GVWR less than or equal to 19,500 pounds, MHD vehicles with a GVWR
greater than 19,500 and less than or equal to 33,000 pounds, and HHD
vehicles with a GVWR greater than 33,000 pounds. These three weight
categories would form the subcategories for vocational vehicles and are
found in 40 CFR 1037.230. The proposed regulations use the term
``averaging set'' which aligns with the regulatory categories or
regulatory class in the context that they define the same set of
products.
    Similar to the proposed Heavy-duty Engine ABT program above,
vocational chassis manufacturers would be able to carry forward
deficits for three years before reconciling the shortfall. However,
just as in the engine category, manufacturers would need to use credits
earned once those credits have been generated to offset a shortfall
before those credits can be banked or traded for additional model
years. This restriction reduces the chance of chassis manufacturers
passing forward deficits before reconciling their shortfalls and
exhausting those credits before reconciling past deficits.
Manufacturers of vocational vehicles that generate a deficit at the end
of the model year could carry that deficit forward for three years
following the model year for which that deficit was generated. Deficits
would need to be reconciled at the reporting dates for year three. We
will accept comments on alternative approaches of reconciling deficit
shortfalls.
(4) Heavy-Duty Pickup Truck and Van Flexibility Provisions
    EPA and NHTSA are proposing specific flexibility provisions for
manufacturers of HD pickups and vans, similar to provisions adopted in
the recent rulemaking for light-duty car and truck GHGs and fuel
economy. Additional flexibilities that apply to the broad range of
heavy-duty vehicles, including HD pickups and vans, are discussed in
Section IV.B. All of these flexibilities would help enable new
technologies to be implemented faster and more cost-effectively than
without a flexibility program, and also help manufacturers deal with
unexpected shifts in sales.
    A manufacturer's credit or debit balance would be determined by
calculating their fleet average performance and comparing it to the
manufacturer's CO2 and fuel consumption standards, as
determined by their fleet mix, for a given model year. A target
standard is determined for each vehicle with a unique payload, towing
capacity and drive configuration. These unique targets, weighted by
their associated production volumes, are summed at the end of the model
year to derive the production volume-weighted manufacturer annual fleet
average standard. A manufacturer would generate credits if its fleet
average CO2 or fuel consumption level is lower than its
standard and would generate debits if its fleet average CO2
or fuel consumption level is above that standard. The end-of-year
reports would provide appropriate data to reconcile pre-compliance
estimates with final model year figures. Similar to the light-duty GHG
program, the agencies would address any ultimate deficits by a possible
void of certificates on a sufficient number of vehicles to address the
shortfall. Enforcement action would entail penalty or other relief as
appropriate or applicable.
    In addition to production weighting, we are proposing that the EPA
credit calculations include a factor for the vehicle useful life, in
miles, in order to allow the expression of credits in metric tons, as
in the light-duty GHG program. The NHTSA credit calculation would use
standard and performance levels in fuel consumption units (gallons per
100 miles), as opposed to fuel economy units (mpg) as done in the
light-duty program, along with the vehicle useful life, in miles,
allowing the expression of credits in gallons. We propose that other
provisions for the generation, tracking, trading, and use of the
credits be the same as those adopted in the light-duty GHG program,
including a 5-year limit on credit carry-forward to future model years
and a 3-year limit on deficit carry-forward (or credit carry-back).
    The total model year fleet credit (debit) calculations would use
the following equations:
CO2 Credits (Mg) = [(CO2 Std-CO2 Act)
x Volume x UL] / 1,000,000
Fuel Consumption Credits (gallons) = (FC Std-FC Act) x Volume x UL x
100

Where:

CO2 Std = Fleet average CO2 standard (g/mi)
FC Std = Fleet average fuel consumption standard (gal/100 mile)
CO2 Act = Fleet average actual CO2 value (g/
mi)
FC Act = Fleet average actual fuel consumption value (gal/100 mile)
Volume = the total production of vehicles in the regulatory class
UL = the useful life for the regulatory class (miles)

    We are proposing that HD pickups and vans comprise a self-contained
averaging set, such that credits earned may be used freely for other HD
pickups and vans but not for other vehicles or engines, and credits
generated by other vehicles or engines may not be used to demonstrate
compliance for HD pickups and vans. We believe this approach is
appropriate because the HD pickup and van fleet is relatively small and
the balanced fleetwide averaging concept is critical for obtaining the
desired technology development in the 2014-2018 timeframe, so that the
potential for large credit flows into or out of this vehicle category
would create unwarranted market uncertainty, which in turn could
jeopardize the impetus to develop needed technologies. An exception to
this approach is proposed for advanced technology credits as discussed
in Section IV.B(2).

    As described above, HD pickup and van manufacturers would be able
to carry forward deficits from their fleet-wide average for three years
before reconciling the shortfall. Manufacturers would be required to
provide a plan in their pre-model year reports showing how they would
resolve projected credit deficits. However, just as in the engine
category, manufacturers would need to use credits earned once those
credits have been generated to offset a shortfall before those credits
can be banked or traded for additional model years. This restriction
reduces the chance of vehicle manufacturers passing forward deficits
before reconciling their shortfalls and exhausting those credits before
reconciling past deficits. We request comments on all aspects of the
proposed HD pickup and van credit program.

B. Additional Proposed Flexibility Provisions

    The agencies are also proposing provisions to facilitate reductions
in GHG emissions and fuel consumption beginning in the 2014 model year.
While we view our proposed ABT and flexibility structure as sufficient
to encourage reduction efforts by heavy-duty highway engine and vehicle
manufacturers, we understand that other efforts may enhance the overall
GHG and fuel consumption reduction we anticipate achieving. Therefore
we propose the following flexibilities to create additional
opportunities for manufacturers to reduce their GHG emissions and fuel
consumption. These opportunities would help provide additional
incentives for manufacturers to innovate and to develop new strategies
and cleaner technologies.
(1) Early Credit Option
    The agencies are proposing that manufacturers of HD engines,
combination tractors, and vocational vehicles be eligible to generate
early credits if they demonstrate improvements in excess of the
proposed standards prior to model year they become effective. The start
dates for EPA's GHG standards and NHTSA's fuel consumption standards
vary by regulatory category (see Section II for the model years when
the standards become effective). Specifically, manufacturers would need
to certify their engines or vehicles to the standards at least six
months before the start of the first model year of the mandatory
standards. The limitations on the use of credits in the ABT programs--
i.e., limiting averaging to within each the regulatory category and
vehicle or engine subcategory--would apply for the proposed early
credits as well.
    NHTSA and EPA also request comment on whether a credit multiplier,
specifically a multiplier of 1.5, would be appropriate to apply to
early credits from HD engines, combination tractors, and vocational
vehicles, as a greater incentive for early compliance. Additionally,
the agencies seek comment on whether or not a requirement that HD
engines, combination tractors, and vocational vehicles that are
eligible to generate early credits, be allowed to do so only if they
certify prior to June 1, 2013 should a multiplier of 1.5 be applied to
early credits.
    We are proposing that manufacturers of HD pickups and vans who
demonstrate improvements for model year 2013 such that their fleet
average emissions and fuel consumption are lower than the model year
2014 standards be eligible for early credits. Under the proposed
structure for the fleet average standards, this credit opportunity
would entail certifying a manufacturer's entire HD pickup and van fleet
in model year 2013, and assessing this fleet against the model year
2014 target levels discussed in Section II. The agencies consider the
proposed availability of early credits to be a valuable complement to
the overall program to the extent that they encourage early
implementation of effective technologies. We request comment on ways
the early credit opportunities can be tailored to accomplish this
objective and protect against unanticipated windfalls.
(2) Advanced Technology Credits
    EPA and NHTSA are proposing targeted provisions that we expect
would promote the implementation of advanced technologies.
Specifically, manufacturers that incorporate these technologies would
be eligible for special credits that could be applied to other heavy-
duty vehicles or engines, including those in other heavy-duty
categories. We seek comment on any conversion factors that may be
needed. Technologies that we propose to make eligible are:
     Hybrid powertrain designs that include energy storage
systems.
     Rankine cycle engines.
     All-electric vehicles.
     Fuel cell vehicles.
    NHTSA and EPA request comment on whether a credit multiplier,
specifically a multiplier of 1.5, would be appropriate to apply to
advanced technology credits, as a greater incentive for their
introduction. NHTSA and EPA request comment on the list of technologies
identified as advanced technologies and whether additional technologies
should be added to the list. NHTSA and EPA also request comment on
whether credits generated from vehicles complying prior to 2014 and
using Advanced SmartWay or Advanced SmartWay II aerodynamic
technologies should be designated as Advanced Technology Credits.
(a) All-Electric Vehicles and HD Pickup Truck and Van Hybrids
    For HD pickup and van hybrids, we propose that testing would be
done using adjustments to the test procedures developed for light-duty
hybrids. NHTSA and EPA are also proposing that all-electric and other
zero emission vehicles produced in model years before 2014 be able to
earn credits for use in the 2014 and later HD pickup and van compliance
program, provided the vehicles are covered by an EPA certificate of
conformity for criteria pollutants. These credits would be calculated
based on the 2014 diesel standard targets corresponding to the
vehicle's work factor, and treated as though they were earned in 2014
for purposes of credit life. Manufacturers would not have to early-
certify their entire HD pickup and van fleet in a model year as for
other early-complying vehicles. NHTSA and EPA are also proposing that
model year 2014 and later EVs and other zero emission vehicles be
factored into the fleet average GHG and fuel consumption calculations
based on the diesel standards targets for their model year and work
factor. If advanced technology credits generated by pickups and vans
are used in another HD vehicle category, these credits would, of
course, be subtracted from the manufacturer's pickup and van category
credit balance.
    In the 2012-2016 MY Light-Duty Vehicle Rule, EPA discussed at
length the issue of whether to account for upstream emissions of GHGs
in assessing the amount of credit to offer to various types of electric
vehicles--that is, GHG emissions associated with generation of the
electricity needed to power the electric vehicle. See 75 FR 25434-
25436. Although acknowledging that such emissions would not be
accounted for if electric vehicle GHG emissions are assessed at zero
for credit generating purposes, EPA believed that this was the
appropriate course in order to provide an incentive for
commercialization of this extremely promising technology. At the same
time, EPA adopted a cumulative cap whereby upstream emissions would be
accounted for if sales of EVs exceeded a given amount.

    The agencies believe that these same considerations apply to heavy-
duty vehicles. Indeed, the agencies believe that introduction of EVs
into the heavy-duty fleet would be less frequent than for light-duty
vehicles, so that there is less risk of dilution of the main standards
by unexpectedly high introduction of EVs into the heavy-duty fleet and
at least an equally compelling reason to provide an incentive for the
technology's commercial introduction. Given the unlikelihood of
significant penetration of the technology in the model years of these
standards, the agencies similarly do not see a need to adopt the type
of cumulative caps which would trigger an upstream emission accounting
procedure as in the light-duty vehicle rule. The agencies solicit
comment on these issues, however.
(b) Vocational Vehicle and Tractor Hybrids
    For vocational vehicles or combination tractors incorporating
hybrid powertrains, we propose two methods for establishing the number
of credits generated, each of which is discussed next. The agencies are
not aware of models that have been adequately peer reviewed with data
that can assess this technology without the conclusion of a comparison
test of the actual physical product.
(i) Chassis Dynamometer Evaluation
    For hybrid certification to generate credits we propose to utilize
chassis testing as an effective way to compare the CO2
emissions and fuel consumption performance of conventional and hybrid
vehicles. We are proposing that heavy-duty hybrid vehicles be certified
using ``A to B'' vehicle chassis dynamometer testing. This concept
allows a hybrid vocational vehicle manufacturer to directly quantify
the benefit associated with use of its hybrid system on an application-
specific basis. The concept would entail testing the conventional
vehicle, identified as ``A'', using the cycles as defined in Section V.
The ``B'' vehicle would be the hybrid version of vehicle ``A''. The
``B'' vehicle would need to be the same exact vehicle model as the
``A'' vehicle. As an alternative, if no specific ``A'' vehicle exists
for the hybrid vehicle that is the exact vehicle model, the most
similar vehicle model would need to be used for testing. We propose to
define the ``most similar vehicle'' as a vehicle with the same
footprint, same payload, same testing capacity, the same engine power
system, the same intended service class, and the same coefficient of
drag.
    To determine the benefit associated with the hybrid system for GHG
performance, the weighted CO2 emissions results from the
chassis test of each vehicle would define the benefit as described
below:

1. (CO2--A-CO2--B)/(CO2--A) = --------
(Improvement Factor)
2. Improvement Factor x GEM CO2 Result--B = -------- (g/ton
mile benefit)

    Similarly, the benefit associated with the hybrid system for fuel
consumption would be determined from the weighted fuel consumption
results from the chassis tests of each vehicle as described below:

3. (Fuel Consumption--A-Fuel Consumption--B)/(Fuel Consumption--A) = --
------ (Improvement Factor)
4. Improvement Factor x GEM Fuel Consumption Result--B = --------
(gallon/1,000 ton mile benefit)

    The credits for the hybrid vehicle would be calculated as described
in the ABT program by Equation IV-5 and Equation IV-6, except that the
result from Equation 2 above replaces the (Std-FEL) value. We are
proposing that the tons of CO2 or gallons of fuel credits
generated by a hybrid vehicle could flow into any regulatory
subcategory.
    The agencies are proposing two sets of duty cycles to evaluate the
benefit depending on the vehicle application to assess hybrid vehicle
performance--without and with PTO systems. The key difference between
these two sets of vehicles is that one set (e.g., delivery trucks) does
not operate a PTO while the other set (e.g., bucket and refuse trucks)
does.
    The first set of duty cycles would apply to the hybrid powertrains
used to improve the motive performance of the vehicles without a PTO
system (such as pickup and delivery trucks). The typical operation of
these vehicles is very similar to the overall drive cycles proposed in
Section II. Therefore, the agencies are proposing to use the same
vehicle drive cycle weightings for testing these vehicles, as shown in
Table IV-2.
[GRAPHIC] [TIFF OMITTED] TP30NO10.047

    The second set of duty cycles apply to testing hybrid vehicles used
in applications such as utility and refuse trucks tend to have
additional benefits associated with use of stored energy, which avoids
main engine operation and related CO2 emissions and fuel
consumption during PTO operation. To appropriately address benefits,
exercising the conventional and hybrid vehicles using their PTO would
help to quantify the benefit to GHG emissions and fuel consumption
reductions. The duty cycle proposed to quantify the hybrid
CO2 and fuel consumption impact over this broader set of
operation would be the three primary drive cycles plus a PTO duty
cycle. Our proposed PTO cycle is based on consideration of using
alternate, appropriate duty cycles with Administrator approval in a
public process. The PTO duty cycle as proposed takes into account the
sales impact and population of utility trucks and refuse haulers. As
described in draft RIA Chapter 3, the agencies are proposing to add an
additional PTO cycle to measure the improvement achieved for this type
of hybrid powertrain application. The proposed weightings for the
hybrids with PTO are included in Table IV-3. The agencies welcome
comments on the proposed drive cycle weightings and the proposed PTO
cycle.

[GRAPHIC] [TIFF OMITTED] TP30NO10.048

(ii) Engine Dynamometer Evaluation
    The engine test procedure we are proposing for hybrid evaluation
involves exercising the conventional engine and hybrid-engine system
based on an engine testing strategy. The basis for the system control
volume, which serves to determine the valid test article, would need to
be the most accurate representation of real world functionality. An
engine test methodology would be considered valid to the extent the
test is performed on a test article that does not mischaracterize
criteria pollutant performance or actual system performance. Energy
inputs should not be based on simulation data which is not an accurate
reflection of actual real world operation. It is clearly important to
be sure credits are generated based on known physical systems. This
includes testing using recovered vehicle kinetic energy. Additionally,
the duty cycle over which this engine-hybrid system would be exercised
would need to reflect the use of the application, while not promoting a
proliferation of duty cycles which prevent a standardized basis for
comparing hybrid system performance. The agencies are proposing the use
of the Heavy-duty FTP cycle for evaluation of hybrid vehicles, which is
the same test cycle proposed for engines used in vocational vehicles.
For powerpack testing, which includes the engine and hybrid systems in
a pre-transmission format, the engine based testing is applicable for
determination of brake-specific emissions benefit versus the engine
standard. For post-transmission powertrain systems and vehicles, the
comparison evaluation based on the Improvement Factor and the GEM
result based on a vehicle drive trace in a powertrain test cell or
chassis dynamometer test cell seem to accurately reflect the
performance improvements associated with these test configurations. It
is important that introduction of clean technology be incentivized
without compromising the program intent of real world improvements in
GHG and fuel consumption performance. The agencies seek comments on the
most appropriate test procedures to accurately reflect the performance
improvement associated with hybrid systems tested using these or other
protocols.
(3) Innovative Technology Credits
    NHTSA and EPA are proposing a credit opportunity intended to apply
to new and innovative technologies that reduce fuel consumption and
CO2 emissions, but for which the reduction benefits are not
captured over the test procedure used to determine compliance with the
standards (i.e., the benefits are ``off-cycle''). See 75 FR 25438-25440
where EPA adopted a similar credit program for MY 2012-2016 light-duty
vehicles. In this case, the `test procedure' includes not only the
Heavy-duty FTP and SET procedures used to measure compliance with the
engine standards, but also the GEM. Eligible innovative technologies
would be those that are newly introduced in one or more vehicle models
or engines, but that are not yet widely implemented in the heavy-duty
fleet. This could include known technologies not yet widely utilized in
a particular subcategory. Further, any credits for these off-cycle
technologies would need to be based on real-world fuel consumption and
GHG reductions that can be measured with verifiable test methods and
representing driving conditions typical of the vehicle application.
    We would not consider technologies to be eligible for these credits
if the technology has a significant impact on CO2 emissions
and fuel consumption over the primary test cycles or are the
technologies on whose performance the various vehicle and engine
standards are premised. However, EPA and NHTSA are aware of some
emerging and innovative technologies and concepts in various stages of
development with CO2 emissions and fuel consumption
reduction potential that might not be adequately captured on the
proposed certification test cycles, and we believe that some of these
technologies might merit some additional CO2 and fuel
consumption credit generating potential for the manufacturer. Examples
include predictive cruise control, gear-down protection, and active
aerodynamic features not exercised in the certification test, such as
adjustable ride height for pickup trucks. We believe it would be
appropriate to provide an incentive to encourage the introduction of
these types of technologies and that a credit mechanism is an effective
way to do so. This optional credit opportunity would be available
through the 2018 model year reflecting that technologies may be common
by then, but the agencies welcome comment on the need to extend beyond
model year 2018.
    EPA and NHTSA propose that credits generated using innovative
technologies be restricted within the subcategory where the credit was
generated. The agencies request comments whether credits generated
using innovative technologies should be fungible across vehicle and
engine categories.
    We are proposing that manufacturers quantify CO2 and
fuel consumption reductions associated with the use of the off-cycle
technologies such that the credits could be applied based on the
proposed metrics (such as g/mile and gal/100 mile for pickup trucks, g/
ton-mile and gal/1,000 ton-mile for tractors and vocational vehicles,
and g/bhp-hr and gal/100 bhp-hr for engines). Credits would have to be
based on real additional reductions of CO2 emissions and
fuel consumption and would need to be quantifiable and verifiable with
a repeatable methodology. Such submissions of data should be submitted
to EPA and NHTSA, and would be subject to a public evaluation process
in which the public would have opportunity for comment. See 75 FR
25440. We propose that the technologies upon which the credits are
based would be subject to full useful life compliance provisions, as
with other emissions controls. Unless the manufacturer can demonstrate
that the technology would not be subject to in-use deterioration over
the useful life of the vehicle, the manufacturer would have to account
for deterioration in the estimation of the credits in order to ensure
that the credits are based on real in-use emissions reductions over the
life of the vehicle.
    In cases where the benefit of a technological approach to reducing
CO2 emissions and fuel consumption cannot be adequately
represented using existing test cycles, EPA and NHTSA would review and
approve as appropriate test procedures and analytical approaches to
estimate the effectiveness of the technology for the purpose of
generating credits. The demonstration program should be robust,
verifiable, and capable of demonstrating the real-world emissions
benefit of the technology with strong statistical significance. See 75
FR

25440. For HD pickups and vans, EPA and NHTSA believe that the 5-cycle
approach currently used in EPA's fuel economy labeling program for
light-duty vehicles may provide a suitable test regimen, provided it
can be reliably conducted on the dynamometer and can capture the impact
of the off-cycle technology (see 71 FR 77872, December 27, 2006). EPA
established the 5-cycle test methods to better represent real-world
factors impacting fuel economy, including higher speeds and more
aggressive driving, colder temperature operation, and the use of air
conditioning.
    The CO2 and fuel consumption benefit of some
technologies may be able to be demonstrated with a modeling approach.
In other cases manufacturers might have to design on-road test programs
that are statistically robust and based on real-world driving
conditions. Whether the approach involves on-road testing, modeling, or
some other analytical approach, the manufacturer would be required to
present a proposed methodology to EPA and NHTSA. EPA and NHTSA would
approve the methodology and credits only if certain criteria were met.
Baseline emissions and control emissions would need to be clearly
demonstrated over a wide range of real-world driving conditions and
over a sufficient number of vehicles to address issues of uncertainty
with the data. Data would need to be on a vehicle model-specific basis
unless a manufacturer demonstrated model-specific data was not
necessary. Approval of the approach to determining a CO2 and
fuel consumption benefit would not imply approval of the results of the
program or methodology; when the testing, modeling, or analyses are
complete the results would likewise be subject to EPA and NHTSA review
and approval. The agencies believe that suppliers and vehicle
manufacturers could work together to develop testing, modeling, or
analytical methods for certain technologies, similar to the SAE
approach used for A/C refrigerant leakage scores. As with the similar
procedure for alternative off-cycle credits under the 2012-2016 MY
light-duty vehicle program, the agencies would include an opportunity
for public comment as part of any approval process.
    The agencies request comments on the proposed approach for off-
cycle emissions credits, including comments on how best to structure
the program. EPA and NHTSA particularly request comments on how the
case-by-case approach to assessing off-cycle innovative technology
credits could best be designed, including ways to ensure the
verification of real-world emissions benefits and to ensure
transparency in the process of reviewing manufacturers' proposed test
methods.

V. NHTSA and EPA Proposed Compliance, Certification, and Enforcement
Provisions

A. Overview

(1) Proposed Compliance Approach
    This section describes EPA's and NHTSA's proposed program to ensure
compliance with EPA's proposed emission standards for CO2,
N2O, and CH4 and NHTSA's proposed fuel
consumption standards, as described in Section II. To achieve the goals
projected in this proposal, it is important for the agencies to have an
effective and coordinated compliance program for our respective
standards. As is the case with the Light-Duty GHG and CAFE program, the
proposed compliance program for heavy-duty vehicles and engines has two
central priorities. (1) To address the agencies' respective statutory
requirements; and (2) to streamline the compliance process for both
manufacturers and the agencies by building on existing practice
wherever possible, and by structuring the program such that
manufacturers can use a single data set to satisfy the requirements of
both agencies. It is also important to consider the provisions of EPA's
existing criteria pollutant program in the development of the approach
used for heavy-duty certification and compliance. The existing EPA
heavy-duty highway engine emissions program has an established
infrastructure and methodology that would allow effective integration
with this proposed GHG and fuel consumption program, without needing to
create new unique processes in many instances. The compliance program
would also need to address the importance of the impact of new control
methods for heavy-duty vehicles as well as other control systems and
strategies that may extend beyond the traditional purview of the
criteria pollutant program.
    The proposed heavy-duty compliance program would use a variety of
mechanisms to conduct compliance assessments, including preproduction
certification and postproduction, in-use monitoring once vehicles enter
customer service. Specifically, the agencies are establishing a
compliance program that utilizes existing EPA testing protocols and
certification procedures. Under the provisions of this program,
manufacturers would have significant opportunity to exercise
implementation flexibility, based on the program schedule and design,
as well as the credit provisions that are being proposed in the program
for advanced technologies. This proposal includes a process to foster
the use of innovative technologies, not yet contemplated in the current
certification process. EPA would continue to conduct compliance preview
meetings which provide the agency an opportunity to review a
manufacturer's new product plans and ABT projections. Given the nature
of the proposed compliance program which would involve both engine and
vehicle compliance for some categories, it would be necessary for
manufacturers to begin pre-certification meetings with EPA early enough
to address issues of certification and compliance for both integrated
and non-integrated product offerings.
    Based on feedback EPA and NHTSA received during the Light-Duty GHG
comment period, both agencies would seek to ensure transparency in the
compliance process. In addition to providing information in published
reports annually regarding the status of credit balances and compliance
on an industry basis, EPA and NHTSA seek comment on additional
strategies for providing information useful to the public regarding
industry's progress toward reducing GHG emissions and fuel consumption
from this sector while protecting sensitive business information.
(a) Heavy-Duty Pickup Trucks and Vans
    The proposed compliance regulations (for certification, testing,
reporting, and associated compliance activities) for heavy-duty pickup
trucks and vans closely track both current practices and the recently
adopted greenhouse gas regulations for light-duty vehicles and trucks.
Thus they would be familiar to manufacturers. EPA already oversees
testing, collects and processes test data, and performs calculations to
determine compliance with both CAFE and CAA standards for Light-Duty.
For Heavy-Duty products that closely parallel light-duty pick-ups and
vans, under a coordinated approach, the compliance mechanisms for both
programs for NHTSA and EPA would be consistent and non-duplicative for
GHG pollutant standards and fuel consumption requirements. Vehicle
emission standards established under the CAA apply throughout a
vehicle's full useful life.
    Under EPA existing criteria pollutant emission standard program for
heavy-duty pickup trucks and vans, vehicle manufacturers certify a
group of vehicles called a test group. A test group

typically includes multiple vehicle lines and model types that share
critical emissions-related features. The manufacturer generally selects
and tests a single vehicle, typically considered ``worst case'' for
criteria pollutant emissions, which is allowed to represent the entire
test group for certification purposes. The test vehicle is the one
expected to be the worst case for the emission standard at issue.
Emissions from the test vehicle are assigned as the value for the
entire test group. However, the compliance program in the recent GHG
regulations for light-duty vehicles, which is essentially the well
established CAFE compliance program, allows and may require
manufacturers to perform additional testing at finer levels of vehicle
models and configurations in order to get more precise model-level fuel
economy and CO2 emission levels. This same approach would be
applied to heavy-duty pickups and vans. Additionally, like the light-
duty program, approved use of analytically derived fuel economy would
be allowed to predict the fuel efficiency and CO2 levels of
some vehicles in lieu of testing when deemed appropriate by the
agencies. The degree to which analytically derived fuel economy would
be allowed and the design of the adjustment factors would be determined
by the agencies.
(b) Heavy-Duty Engines
    Heavy-duty engine certification and compliance for traditional
criteria pollutants has been established by EPA in its current general
form since 1985. In developing a program to address GHG pollutants, it
is important to build upon the infrastructure for certification and
compliance that exists today. At the same time, it is necessary to
develop additional tools to address compliance with GHG emissions
requirements, since the proposed standard reflect control strategies
that extend beyond those of traditional criteria pollutants. In so
doing, the agencies are proposing use of EPA's current engine test
based strategy--currently used for criteria pollutant compliance--to
also measure compliance for GHG emissions. The agencies are also
proposing to add new strategies to address vehicle specific designs and
hardware which impact GHG emissions. The traditional engine approach
would largely match the existing criteria pollutant control strategy.
This would allow the basic tools for certification and compliance,
which have already been developed and implemented, to be expanded for
carbon dioxide, methane, and nitrous oxide. Engines with similar
emissions control technology may be certified in engine families, as
with criteria pollutants.
    For EPA, the proposed approach for certification would follow the
current process, which would require manufacturer submission of
certification applications, approval of the application, and receipt of
the certificate of conformity prior to introduction into commerce of
any engines. EPA proposes the certificate of conformity be a single
document that would be applicable for both criteria pollutants and
greenhouse gas pollutants. NHTSA would assess compliance with its fuel
consumption standards based on the results of the EPA GHG emissions
compliance process for each engine family.
(c) Class 7 and 8 Combination Tractors and Class 2b-8 Vocational
Vehicles
    Currently, except for HD pickups and vans, EPA does not directly
regulate exhaust emissions from heavy-duty vehicles as a complete
entity. Instead, a compliance assessment of the engine is undertaken as
described above. Vehicle manufacturers installing certified engines are
required to do so in a manner that maintains all functionality of the
emission control system. While no process exists for certifying these
heavy-duty vehicles, the agencies believe that a process similar to the
one we propose for use for heavy-duty engines can be applied to the
vehicles.
    The agencies are proposing related certification programs for
heavy-duty vehicles. Manufacturers would divide their vehicles into
families and submit applications to each agency for certification for
each family. However, the demonstration of compliance would not require
emission testing of the complete vehicle, but would instead involve a
computer simulation model, GEM. This modeling tool uses a combination
of manufacturer-specified and agency-defined vehicle parameters to
estimate vehicle emissions and fuel consumption. This model would then
be exercised over certain drive cycles. EPA and NHTSA are proposing the
duty cycles over which Class 7 and 8 combination tractors would be
exercised to be: 65 mile per hour steady state cruise cycle, the 55
mile per hour steady state cruise cycle, and the California ARB
transient cycle. Additional details regarding these duty cycles will be
addressed in Section V.D(1)(b) below. Over each duty cycle, the
simulation tool would return the expected CO2 emissions, in
g/ton-mile, and fuel consumption, gal/1,000 ton-mile, which would then
be compared to the standards.

B. Heavy-Duty Pickup Trucks and Vans

(1) Proposed Compliance Approach
    EPA and NHTSA are proposing new emission standards to control
greenhouse gases (GHGs) and reduce fuel consumption from heavy-duty
trucks between a gross vehicle weight rating between 8,500 and 14,000
pounds that are not already covered under the MY 2012-2016 light-duty
truck and medium-duty passenger vehicle GHG standards. In this section
``trucks'' now refers to heavy-duty pickup trucks and vans between
8,500 and 14,000 pounds not already covered under the above light-duty
rule.
    First, EPA is proposing fleet average emission standards for
CO2 on a gram per mile (g/mile) basis and NHTSA is proposing
fuel consumption standards on a gal/100 mile basis that would apply to
a manufacturer's fleet of heavy-duty trucks and vans with a GVWR from
8,500 pounds to 14,000 pounds (Class 2b and 3). CO2 is the
primary pollutant resulting from the combustion of vehicular fuels, and
the amount of CO2 emitted is highly correlated to the amount
of fuel consumed. In addition, the EPA is proposing separate emissions
standards for three other GHG pollutants: CH4,
N2O, and HFC. CH4 and N2O emissions
relate closely to the design and efficient use of emission control
hardware (i.e., catalytic converters). The standards for CH4
and N2O would be set as caps that would limit emissions
increases and prevent backsliding from current emission levels. In lieu
of meeting the caps, EPA is optionally proposing that manufacturer
could offset any N2O emissions or any CH4
emissions above the cap by taking steps to further reduce
CO2. Separately, EPA is proposing to set standards to
control the leakage of HFCs from air conditioning systems. EPA and
NHTSA are requesting comment on the opportunity for manufacturers to
earn credits toward the fleet-wide average CO2 and fuel
consumption standards for improvements to air conditioning system
efficiency that reduce the load on the engine and thereby reduce
CO2 emissions and fuel consumption.
    Previously, complete vehicles with a Gross Vehicle Weight Rating of
8,500-14,000 pounds could be certified according to 40 CFR part 86,
subpart S. These heavy-duty chassis certified vehicles were required to
pass emissions on both the Light-duty FTP and HFET (California
certified only

requirement).\197\ These proposed rules would use the same testing
procedures already required for heavy-duty chassis certification,
namely the Light-duty FTP and the HFET but extend the requirement for
chassis certification for CO2 emissions to diesel-powered
vehicles. Currently, chassis certification is a gasoline requirement
and a diesel option. Using the data from these two tests, EPA and NHTSA
would compare the CO2 emissions and fuel consumption results
against the attribute-based target. The attribute upon which the
CO2 standard would be based would be a function of vehicle
payload, vehicle towing capacity and two-wheel versus four-wheel drive
configuration as discussed in Section II.C(1)(b) of this notice. The
attribute-based standard targets would be used to determine a
manufacturer fleet standard and would be subject to an average banking
and trading scheme similar to the light-duty GHG rule.
---------------------------------------------------------------------------

    \197\ Diesel engines are engine-certified with the option to
chassis certification Federally and for California.
---------------------------------------------------------------------------

    This proposal would require nearly all heavy-duty trucks between
8,500 and 14,000 pounds gross vehicle weight rating that are not
already covered under the light-duty truck and medium-duty passenger
vehicle GHG standards to have a CO2, CH4 and
N2O values assigned to them, either from actual chassis
dynamometer testing or from the results of a representative vehicle in
the test group with appropriate adjustments made for differences. This
requirement would apply based on whether the vehicle manufacturer sold
the vehicle as a complete or nearly complete vehicle.\198\
Manufacturers would be allowed to exclude vehicles they sell to
secondary manufacturers without cabs (often known as rolling chassis),
as well as a very small number of vehicles sold with cabs.
Specifically, a manufacturer could certify up to two percent of its
vehicles with complete cabs, or up to 2,000 vehicles if its total sales
in this category was less than 100,000, as vocational vehicles. To the
extent manufacturers are allowed to engine certify for criteria
pollutant (non-GHG) requirements today, they would be allowed to
continue to do so under the proposed regulations.
---------------------------------------------------------------------------

    \198\ The proposed regulations would use the term ``cab-complete
vehicle'' to refer to incomplete vehicles sold with complete cabs,
but lacking a cargo carrying container.
---------------------------------------------------------------------------

    Because the program being proposed for heavy-duty pickup trucks and
vans is so similar to the program recently adopted for light-duty
trucks and codified in 40 CFR part 86, subpart S, EPA is proposing to
apply most of those subpart S regulatory provisions to heavy-duty
pickup trucks and vans and to not recodify them in the new part 1037.
Most of the new part 1037 would not apply for heavy-duty pickup trucks
and vans. How 40 CFR part 86 applies, and which provisions of the new
40 CFR part 1037 apply for heavy-duty pickup trucks and vans is
described in Sec.  1037.104.
(a) Certification Process
    CAA section 203(a)(1) prohibits manufacturers from introducing a
new motor vehicle into commerce unless the vehicle is covered by an
EPA-issued certificate of conformity. Section 206(a)(1) of the CAA
describes the requirements for EPA issuance of a certificate of
conformity, based on a demonstration of compliance with the emission
standards established by EPA under section 202 of the Act. The
certification demonstration requires emission testing, and must be done
for each model year.\199\
---------------------------------------------------------------------------

    \199\ CAA Section 206(a)(1).
---------------------------------------------------------------------------

    Under existing heavy-duty chassis certification and other EPA
emission standard programs, vehicle manufacturers certify a group of
vehicles called a test group. A test group typically includes multiple
vehicle car lines and model types that share critical emissions-related
features.\200\ The manufacturer generally selects and tests one vehicle
to represent the entire test group for certification purposes. The test
vehicle is the one expected to be the worst case for the criteria
emission standard at issue.
---------------------------------------------------------------------------

    \200\ The specific test group criteria are described in 40 CFR
86.1827-01, car lines and model types have the meaning given in 40
CFR 86.1803-01.
---------------------------------------------------------------------------

    EPA requires the manufacturer to make a good faith demonstration in
the certification application that vehicles in the test group will both
(1) comply throughout their useful life within the emissions bin
assigned, and (2) contribute to fleetwide compliance with the
applicable emissions standards when the year is over. EPA issues a
certificate for the vehicles included in the test group based on this
demonstration, and includes 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 with the applicable standards.
    The certification process often occurs several months prior to
production and manufacturer testing may occur months before the
certificate is issued. The certification process for the existing
heavy-duty chassis program is an efficient way for manufacturers to
conduct the needed testing well in advance of certification, and to
receive certificates in a time frame which allows for the orderly
production of vehicles. The use of conditions on the certificate has
been an effective way to ensure that manufacturers comply throughout
their useful life and meet fleet standards when the model year is
complete and the accounting for the individual model sales is
performed. EPA has also adopted this approach as part of its LD GHG
compliance program.
    EPA is proposing to similarly condition each certificate of
conformity for the GHG program upon a manufacturer's good faith
demonstration of compliance with the manufacturer's fleetwide average
CO2 standard. The following discussion explains how EPA
proposes to integrate the proposed vehicle certification program into
the existing certification program.
    An integrated approach with NHTSA will be undertaken to allow
manufacturers a single point of entry to address certification and
compliance. Vehicle manufacturers would initiate the formal
certification process with their submission of application for a
certificate of conformity to EPA.
(b) Certification Test Groups and Test Vehicle Selection
    For heavy-duty chassis certification to the criteria emission
standards, manufacturers currently as mentioned above divide their
fleet into ``test groups'' for certification purposes. The test group
is EPA's unit of certification; one certificate is issued per test
group. These groupings cover vehicles with similar emission control
system designs expected to have similar emissions performance (see 40
CFR 86.1827-01). The factors considered for determining test groups
include Gross Vehicle Weight, combustion cycle, engine type, engine
displacement, number of cylinders and cylinder arrangement, fuel type,
fuel metering system, catalyst construction and precious metal
composition, among others. Vehicles having these features in common are
generally placed in the same test group.\201\
---------------------------------------------------------------------------

    \201\ EPA provides for other groupings in certain circumstances,
and can establish its own test groups in cases where the criteria do
not apply. See 40 CFR 86.1827-01(b), (c) and (d).
---------------------------------------------------------------------------

    EPA is proposing to retain the current test group structure for
heavy-duty pickups and vans in the certification requirements for
CO2. At the time of

certification, manufacturers would use the CO2 emission
level from the Emission Data Vehicle as a surrogate to represent all of
the models in the test group. However, following certification further
testing would generally be allowed for compliance with the fleet
average CO2 standard as described below. EPA's issuance of a
certificate would be conditioned upon the manufacturer's subsequent
model level testing and attainment of the actual fleet average, much
like light-duty CAFE and GHG compliance requires. Under the current
program, complete heavy-duty Otto-cycle vehicles under 14,000 pounds
Gross Vehicle Weight Rating are required to chassis certify (see 40 CFR
86.1801-01(a)). The current program allows complete heavy-duty diesel
vehicles under 14,000 pounds GVWR to optionally chassis certify (see 40
CFR 86.1863-07(a)). As discussed earlier, these proposed rules would
now require all HD vehicles under 14,000 pounds GVWR to chassis certify
except as noted in Section II.
    EPA recognizes that the existing heavy-duty chassis test group
criteria do not necessarily relate to CO2 emission levels.
See 75 FR 25472. For instance, while some of the criteria, such as
combustion cycle, engine type and displacement, and fuel metering, may
have a relationship to CO2 emissions, others, such as those
pertaining to the some exhaust aftertreatment features, may not. In
fact, there are many vehicle design factors that impact CO2
generation and emissions but are not major factors included in EPA's
test group criteria.\202\ Most important among these may be vehicle
weight, horsepower, aerodynamics, vehicle size, and performance
features. To remedy this, EPA is considering allowing manufacturers
provisions similar to the LD GHG rule that would yield more accurate
CO2 estimates than only using the test group emission data
vehicle CO2 emissions.
---------------------------------------------------------------------------

    \202\ EPA noted this potential lack of connection between fuel
economy testing and testing for emissions standard purposes when it
first adopted fuel economy test procedures. See 41 FR 38677, Sept.
10, 1976.
---------------------------------------------------------------------------

    EPA believes that the current test group concept is appropriate for
N2O and CH4 because the technologies that would
be employed to control N2O and CH4 emissions may
generally be the same as those used to control the criteria pollutants.
However, manufacturers would determine if this approach is adequate
method for N2O and CH4 emissions compliance or if
testing on additional vehicles is required to ensure the entire fleet
meet applicable standards.
    As just discussed, the ``worst case'' vehicle a manufacturer
selects as the Emissions Data Vehicle to represent a test group under
the existing regulations (40 CFR 86.1828-01) may not have the highest
levels of CO2 in that group. For instance, there may be a
heavier, more powerful configuration that would have higher
CO2, but may, due to the way the catalytic converter has
been matched to the engine, actually have lower NOX, CO, PM
or HC emissions. Therefore, EPA is proposing to require a single
Emission Data Vehicle that would represent the test group for both
criteria pollutant and CO2 certification. The manufacturer
would be allowed to initially apply the Emission Data Vehicle's
CO2 emissions value to all models in the test group, even if
other models in the test group are expected to have higher
CO2 emissions. However, as a condition of the certificate,
this surrogate CO2 emissions value would generally be
replaced with actual, model-level CO2 values based on
results from additional testing that occurs later in the model year
much like the light-duty CAFE program, or through the use of approved
methods for analytically derived fuel economy. This model level data
would become the official certification test results (as per the
conditioned certificate) and would be used to determine compliance with
the fleet average. Only if the test vehicle is in fact the worst case
CO2 vehicle for the test group could the manufacturer elect
to apply the Emission Data Vehicle emission levels to all models in the
test group for purposes of calculating fleet average emissions.
Manufacturers would be unlikely to make this choice, because doing so
would ignore the emissions performance of vehicle models in their fleet
with lower CO2 emissions and would unnecessarily inflate
their CO2 fleet average. Testing at the model level would
necessarily increase testing burden beyond the minimum Emission Data
Vehicle testing.
    EPA requests comment regarding whether the existing heavy-duty
chassis test group can adequately represent CO2 emissions
for certification purposes, and whether the Emission Data Vehicle's
CO2 emission level is an appropriate surrogate for all
vehicles in a test group at the time of certification, given that the
certificate would be conditioned upon additional model level testing
occurring during the year and that the surrogate CO2
emission values would be replaced with model-level emissions data from
those tests. Comments should also address EPA's desire to minimize the
up-front pre-production testing burden and whether the proposed
efficiencies would be balanced by the requirement to test all model
types in the fleet by the conclusion of the model year in order to
establish the fleet average CO2 levels.
    As explained in Sections II and III, there are two standards that
the manufacturer would be subject to, the fleet average standard and
the in-use standard for the useful life of the vehicle. Compliance with
the fleet average standard is based on production weighted averaging of
the test data that applies for each model, For each model, the in-use
standard is set at 10 percent higher than the level used for that model
in calculating the fleet average. The certificate covers both of these
standards, and the manufacturer has to demonstrate compliance with both
of these standards for purposes of receiving a certificate of
conformity. The certification process for the in-use standard is
discussed above.
(c) Pre-Model Year (or Compliance Plan) Reporting
    EPA and NHTSA are proposing that manufacturers submit a compliance
plan for their entire fleet prior to the certification of any test
group in a given model year. Preferably, this compliance plan would be
submitted at the manufacturer's annual certification preview meeting.
This preview meeting is typically held before the earliest date that
the model year can begin. The earliest a model year can begin is
January 2nd of the calendar year prior to the model year. This plan
would include the manufacturer's estimate of its attribute-based
standard, along with a demonstration of compliance with the standard
based on projected model-level CO2 emissions and fuel
consumption, and production estimates. This information would be
similar to the information submitted to NHTSA and EPA in the pre-model
year report required for CAFE compliance for light-duty vehicles.
Included in the compliance plan, manufacturers seeking to take
advantage of credit flexibilities would include these in their
compliance demonstration. Similarly, the compliance demonstration would
need to include a credible plan for addressing deficits accrued in
prior model years. EPA and NHTSA would review the compliance plan for
technical viability and conduct a certification preview discussion with
the manufacturer. The agencies would view the compliance plan as part
of the manufacturer's good faith demonstration, but understands that
initial projections can vary considerably from the reality of final
production and emission results. In

addition, the compliance plan must be approved by the EPA Administrator
prior to any certificate of compliance being issued. The agencies
request comment on the proposal to evaluate manufacturer compliance
plans prior to the beginning of model year certification.
(d) Demonstrating Compliance With the Proposed Standards
(i) CO2 and Fuel Consumption Fleet Standards
    As noted, attribute-based CO2 standards result in each
manufacturer having a fleet average CO2 standard unique to
its heavy-duty truck fleet of GVWR between 8,500-14,000 pounds and that
standard would be separate from the standard for passenger cars, light-
trucks, and other heavy-duty trucks. The standards depend on those
attributes corresponding to the relative capability, or ``work
factor'', of the vehicle models produced by that manufacturer. The
proposed attributes used to determine the stringency of the
CO2 standard are payload and towing capacity as described in
Section II.C of this notice. Generally, fleets with a mix of vehicles
with increased payloads or greater towing capacity (or utilizing four
wheel drive configurations) would face numerically less stringent
standards (i.e., higher CO2 grams/mile standards) than
fleets consisting of less powerful vehicles. (However, the standards
would be expected to be equally challenging and achieve similar percent
reductions.) Although a manufacturer's fleet average standard could be
estimated throughout the model year based on projected production
volume of its vehicle fleet, the final compliance values would be based
on the final model year production figures. A manufacturer's
calculation of fleet average emissions at the end of the model year
would be based on the production-weighted average emissions of each
model in its fleet. The payload and towing capacity inputs used to
determine manufacturer compliance with these proposed rules would be
the advertised values.
    The agencies propose to use the same general vehicle category
definitions that are used in the current EPA HD chassis certification
(See 40 CFR 86.1816-05). The new vehicle category definitions differ
slightly from the EPA definitions for Heavy-duty Vehicle definitions
for the existing program, as well as other EPA vehicle programs.
Mainly, manufacturers would be able to test, and possibly model, more
configurations of vehicles than were historically in a given test
group. The existing criteria pollutant program requires the worst case
configuration be tested for emissions certification. For HD chassis
certification, this usually meant only testing the vehicle with the
highest ALVW, road-load, and engine displacement within a given test
group. This worst case configuration may only represent a small
fraction of the test group production volume. By testing the worst
case, albeit possibly small volume, vehicle configuration, the EPA had
a reasonable expectation that all represented vehicles would pass the
given emissions standards. Since CO2 standards are a fleet
standard based on a combination of sales volume and work factor (i.e.,
payload and towing capability), it may be in a manufacturer's best
interest to test multiple configurations within a given test group to
more accurately estimate the fleet average CO2 emission
levels and not accept the worst case vehicle test results as
representative of all models. Additionally, vehicle models for which a
manufacturer desires to use analytically derived fuel economy (ADFE) to
estimate CO2 emission levels may need additional actual test
data for vehicle models of similar but not identical configurations.
The agencies are requesting comment on allowing the manufacturer to
test as many configurations within a test group as the manufacturer
requires in order to best represent the volumes of each configuration
within that test group. The agencies are also requesting comment on
using an ADFE approach similar to that used by light-duty vehicles, as
explained in the light-duty vehicle/light-duty truck EPA guidance
document CCD-04-06 titled ``Updated Analytically Derived Fuel Economy
(ADFE) Policy for 2005 MY and Later'', but expanded to a greater
fraction of possible subconfigurations and using lower confidence
limits than used for light-duty vehicles and light-duty trucks.
    The agencies are proposing the use of ADFE similar to that allowed
for light-duty vehicles in 40 CFR 600.006-08(e). This provision would
allow EPA and NHTSA to accept analytical expressions to generate
CO2 and fuel economy that have been approved in advance by
the agencies.
    For model years 2014 through 2017, or earlier if a manufacturer is
certifying in order to generate early credits, EPA is proposing the
equation and parameter values as expressed in Section II C or assigning
a CO2 level to an individual vehicle's relevant attributes.
These CO2 values would be production weighted to determine
each manufacturer's fleet average. Each parameter would change on an
annual basis, resulting in the annual increase in stringency. For the
function used to describe the proposed standard, see Section II.C of
this notice.
    The GHG and fuel economy rulemaking for light-duty vehicles adopted
a carbon balance methodology used historically to determine fuel
consumption for the light-duty labeling and CAFE programs, whereby the
carbon-related combustion products HC and CO are included on an
adjusted basis in the compliance calculations, along with
CO2. The resulting carbon-related exhaust emissions (CREE)
of each test vehicle is calculated and it is this value, rather than
simply CO2 emissions, that is used in compliance
determinations. The difference between the CREE and CO2 is
typically very small.
    NHTSA and EPA are not proposing to adopt the CREE methodology for
HD pickups and vans, and so are not proposing to adjust CO2
emissions to further account for additional HC and CO. The basis of the
CREE methodology in historical labeling and CAFE programs is not
relevant to HD pickups and vans, because these historical programs do
not exist for HD vehicles. Furthermore, test data used in this proposal
for standards-setting has not been adjusted for this effect, and so it
would create an inconsistency, albeit a small one, to apply it for
compliance with the numerical standards we are proposing. Finally, it
would add complexity to the program with little real world benefit. We
request comment on this proposed approach.
(ii) CO2 In-Use Standards and Testing
    Section 202(a)(1) of the CAA requires emission standards to apply
to vehicles throughout their statutory useful life. Section II.B(3)(b)
of this proposal discusses in-use standards.
    Currently, EPA regulations require manufacturers to conduct in-use
testing as a condition of certification for heavy-duty trucks between
8,500 and 14,000 gross vehicle weight that are chassis certified. The
vehicles are tested to determine the in-use levels of criteria
pollutants when they are in their first and third years of service.
This testing is referred to as the In-Use Verification Program, which
was first implemented as part of EPA's CAP 2000 certification program
(see 64 FR 23906, May 4, 1999).
    EPA is requesting comment on applying the in-use program already
set forth in the 2012-2016 MY light-duty vehicle rule to heavy-duty
pickups and vans. The In-Use Verification Program for heavy-duty
pickups and vans would follow the same general provisions of the light-
duty program in regard to

testing, vehicle selection, and reporting. See 75 FR 25474-25476.
(e) Cab-Chassis Vehicles and Complete Class 4 Vehicles
    As discussed in Section I.C(2)(a), we are proposing to include most
cab-chassis Class 2b and 3 vehicles in the complete HD pickup and van
program. Because their numbers are relatively small, and to reduce the
testing and compliance tracking burden to manufacturers, we would treat
these vehicles as equivalent to the complete van or truck product they
are derived from. The manufacturer would determine which complete
vehicle configuration it produces most closely matches the cab-chassis
product leaving its facility, and would include each of these cab-
chassis vehicles in the fleet averaging calculations as though it were
identical to the corresponding complete vehicle.
    Any in-use testing of these vehicles would do likewise, with
loading of the tested vehicle to a total weight equal to the ALVW of
the corresponding complete vehicle configuration. If the secondary
manufacturer had altered or replaced any vehicle components in a way
that would substantially affect CO2 emissions from the
tested vehicle (e.g., axle ratio has been changed for a special purpose
vehicle), the vehicle manufacturer could request that EPA not test the
vehicle or invalidate a test result. Secondary (finisher) manufacturers
would not be subject to requirements under this provision, other than
to comply with anti-tampering regulations. However, if they modify
vehicle components in such a way that GHG emissions and fuel
consumption are substantially affected, they become manufacturers
subject to the standards under this proposal.
    We realize that this approach does not capture the likely loss of
aerodynamic efficiency involved in converting these vehicles from
standard pickup trucks or vans to ambulances and the like, and thus it
could assign them lower GHG emissions and fuel consumption than they
deserve. However, we feel that this approach strikes a fair balance
between the alternatives--grouping these vehicles with vocational
vehicles subject only to engine standards and tire requirements, or
creating a complex and burdensome program that forces vehicle
manufacturers to track, and perhaps control, a plethora of vehicle
configurations they currently do not manage. We request comment on this
proposed provision and any suggestions for ways to improve it.
    Some complete Class 4 trucks are very similar to complete Class 3
pickup truck models, including their overall vehicle architecture and
use of the same basic engines. EPA and NHTSA request comment on whether
these vehicles should be regulated as part of the HD pickup and van
category and thereby be subject to that regulatory regime (i.e.,
standard stringency, chassis-based compliance for entire vehicle,
credit opportunities limited to HD pickup and van subcategory, etc.),
instead of as vocational vehicles as currently proposed. Comment is
also requested on whether such chassis certification should be allowed
as a manufacturer's option instead, and on whether vehicles so
certified for GHG emissions and fuel consumption should also be allowed
to certify to chassis-based criteria pollutant standards as well.
Commenters are asked to address the environmental impacts of this
potential change.
(2) Proposed Labeling Provisions
    HD pickups and vans currently have vehicle emission control
information labels showing compliance with criteria pollutant
standards, similar to emission control information labels for engines.
As with engines, we believe this label is sufficient.
(3) Other Certification Issues
(a) Carryover Certification Test Data
    EPA's proposed certification program for vehicles allows
manufacturers to carry certification test data over from one model year
to the next, when no significant changes to models are made. EPA will
also apply this policy to CO2, N2O and
CH4 certification test data.
(b) Compliance Fees
    The CAA allows EPA to collect fees to cover the costs of issuing
certificates of conformity for the classes of vehicles and engines
covered by this proposal. On May 11, 2004, EPA updated its fees
regulation based on a study of the costs associated with its motor
vehicle and engine compliance program (69 FR 51402). At the time that
cost study was conducted the current rulemaking was not considered.
    At this time the extent of any added costs to EPA as a result of
this proposal is not known. EPA will assess its compliance testing and
other activities associated with the rule and may amend its fees
regulations in the future to include any warranted new costs.

C. Heavy-Duty Engines

(1) Proposed Compliance Approach
    Section 203 of the CAA requires that all motor vehicles and engines
sold in the United States to carry a certificate of conformity issued
by the U.S. EPA. For heavy-duty engines, the certificate specifies that
the engine meets all requirements as set forth in the regulations (40
CFR part 86, subpart N, for criteria pollutants) including the
requirement that the engine be compliant with emission standards. This
demonstration is completed through emission testing as well as
durability testing to determine the level of emissions deterioration
throughout the useful life of the engine. In addition to compliance
with emission standards, manufacturers are also required to warrant
their products against emission defects, and demonstrate that a service
network is in place to correct any such conditions. The engine
manufacturer also bears responsibility in the event that an emission-
related recall is necessary. Finally, the engine manufacturer is
responsible for tracking and ensuring correct installation of any
emission related components installed by a second party (i.e., vehicle
manufacturer). EPA believes this compliance structure is also valid for
administering the proposed GHG regulations for heavy-duty engines.
(a) Certification Process
    In order to obtain a certificate of conformity, engine
manufacturers must complete a compliance demonstration, normally
consisting of test data from relatively new (low-hour) engines as well
as supporting documentation, showing that their product meets emission
standards and other regulatory requirements. To account for aging
effects, low-hour test results are coupled with testing-based
deterioration factors (DFs), which provide a ratio (or offset) of end-
of-life emissions to low-hour emissions for each pollutant being
measured. These factors are then applied to all subsequent low-hour
test data points to predict the emissions behavior at the end of the
useful life.
    For purposes of this compliance demonstration and certification,
engines with similar engine hardware and emission characteristics
throughout their useful life may be grouped together in engine
families, consistent with current criteria-pollutant certification
procedures. Examples of such characteristics are the combustion cycle,
aspiration method, and aftertreatment system. Under this system, the
worst-case engine (``parent rating'') is selected based on having the
highest fuel feed per engine stroke, and all emissions testing is
completed on this model. All other models within the family (``child
ratings'') are expected to have emissions at or below the parent model
and therefore in compliance with emission standards. Any engine within
the family

can be subject to selective enforcement audits, in-use, confirmatory,
or other compliance testing.
    We are proposing to continue to use this approach for the selection
of the worst-case engine (``parent rating'') for fuel consumption and
GHG emissions as well. We believe this is appropriate because this
worst case engine configuration would be expected to have the highest
in-use fuel consumption and GHG emissions within the family. We note
that lower engine ratings contained within this family would be
expected to have a higher fuel consumption rate when measured over the
Federal Test Procedures as expressed in terms of fuel consumption per
brake horsepower hour. This higher fuel consumption rate is misleading
in the context of comparing engines within a single engine family. This
seeming contradiction can be most easily understood in terms of an
example. For a typical engine family a top rating could be 500
horsepower with a number of lower engine ratings down to 400 horsepower
or lower included within the family. When installed in identical trucks
the 400 and 500 horsepower engines would be expected to operate
identically when the demanded power from the engines is 400 horsepower
or less. So in the case where in-use driving never included
acceleration rates leading to horsepower demand greater than 400
horsepower, the two trucks with the 400 and 500 horsepower engines
would give identical fuel consumption and GHG performance. When the
desired vehicle acceleration rates were high enough to require more
than 400 horsepower, the 500 horsepower truck would accelerate faster
than the 400 horsepower truck resulting in higher average speeds and
higher fuel consumption and GHG emissions measured on a per mile or per
ton-mile basis. Hence, the higher rated engine family would be expected
to have the highest in-use fuel consumption and CO2
emissions.
    The reason that the lower engine ratings appear to have worse fuel
consumption relates to our use of a brake specific work metric. The
brake specific metric measures power produced from the engine and
delivered to the vehicle ignoring the parasitic work internal to the
engine to overcome friction and air pumping work within the engine. The
fuel consumed and GHG emissions produced to overcome this internal work
and to produce useful (brake) work are both measured in the test cycle
but only the brake work is reflected in the calculation of the fuel
consumption rate. This is desirable in the context of reducing fuel
consumption as this approach rewards engine designs that minimize this
internal work through better engine designs. The less work that is
needed internal to the engine, the lower the fuel consumption will be.
If we included the parasitic work in the calculation of the rate, we
would provide no incentive to reduce internal friction and pumping
losses. However, when comparing two engines within the very same family
with identical internal work characteristics, this approach gives a
misleading comparison between two engines as described above. This is
the case because both engines have an identical fuel consumption rate
to overcome internal work but different rates of brake work with the
higher horsepower rating having more brake work because the test cycle
is normalized to 100 percent of the engine's rated power. The fuel
consumed for internal work can be thought of as a fixed offset
identical between both engines. When this fixed offset is added to the
fuel consumed for useful (brake) work over the cycle, it increases the
overall fuel consumption (the numerator in the rate) without adding any
work to the denominator. This fixed offset identical between the two
engines has a bigger impact on the lower engine rating. In the extreme
this can be seen easily. As the engine ratings decrease and approach
zero, the brake work approaches zero and the calculated brake specific
fuel consumption approaches infinity. For these reasons, we are
proposing that the same selection criteria, as outlined in 40 CFR part
86, subpart N, be used to define a single engine family designation for
both criteria pollutant and GHG emissions. Further, we are proposing
that for fuel consumption and CO2 emissions only any
selective enforcement audits, in-use, confirmatory, or other compliance
testing would be limited to the parent rating for the family. This
approach is being contemplated for administrative convenience and we
seek comments on alternatives to address compliance testing. Consistent
with the current regulations, manufacturers may electively subdivide a
grouping of engines which would otherwise meet the criteria for a
single family if they have evidence that the emissions are different
over the useful life.
    The agency utilizes a 12-digit naming convention for all mobile-
source engine families (and test groups for vehicles). This convention
is also shared by the California Air Resources Board which allows
manufacturers to potentially use a single family name for both EPA and
California ARB certification. Of the 12 digits, 9 are EPA-defined and
provide identifying characteristics of the engine family. The first
digit represents the model year, through use of a predefined code. For
example, ``A'' corresponds to the 2010 model year and ``B'' corresponds
to the 2011 model year. The 5th position corresponds to the industry
sector code, which includes such examples as light-duty vehicle (V) and
heavy-duty diesel engines (H). The next three digits are a unique
alphanumeric code assigned to each manufacturer by EPA. The next four
digits describe the displacement of the engine; the units of which are
dependent on the industry segment and a decimal may be used when the
displacement is in liters. For engine families with multiple
displacements, the largest displacement is used for the family name.
For on-highway vehicles and engines, the tenth character is reserved
for use by California ARB. The final characters (including the 10th
character in absence of California ARB guidance) left to the
manufacturer to determine, such that the family name forms a unique
identifying characteristic of the engine family.
    This convention is well understood by the regulated industries,
provides sufficient detail, and is flexible enough to be used across a
wide spectrum of vehicle and engine categories. In addition, the
current harmonization with other regulatory bodies reduces
complications for affected manufacturers. For these reasons, we are not
proposing any major changes to this naming convention for this
proposal. There may be additional categories defined for the 5th
character to address heavy-duty vehicle test groups, however that will
be discussed later.
    As with criteria pollutant standards, the heavy-duty diesel
regulatory category is subdivided into three regulatory subcategories,
depending on the GVW of the vehicle in which the engine will be used.
These regulatory subcategories are defined as light-heavy-duty (LHD)
diesel, medium heavy-duty (MHD) diesel, and heavy heavy-duty (HHD)
diesel engines. All heavy-duty gasoline engines are grouped into a
single subcategory. Each of these regulatory subcategories are expected
to be in service for varying amounts of time, so they each carry
different regulatory useful lives. For this reason, expectations for
demonstrating useful life compliance differ by subcategory,
particularly as related to deterioration factors.
    Light heavy-duty diesel engines (and all gasoline heavy-duty
engines) have

the same regulatory useful life as a light-duty vehicle (110,000
miles), which is significantly shorter than the other heavy-duty
regulatory subcategories. Therefore, we believe it is appropriate to
maintain commonality with the light-duty GHG rule. During the light-
duty GHG rulemaking, the conclusion was reached that no significant
deterioration would occur over the useful life. Therefore, EPA is
proposing to specify that manufacturers would use assigned DFs for
CO2 and the values would be zero (for additive DFs) and one
(for multiplicative DFs). EPA is interested in data that addresses this
issue.
    For the medium heavy-duty and heavy heavy-duty diesel engine
segments, the regulatory useful lives are significantly longer (185,000
and 435,000 miles, respectively). For this reason, the agency is not
convinced that engine/aftertreatment wear will not have a negative
impact on GHG emissions. To address useful life compliance for MHD and
HHD diesel engines certified to GHG standards, we believe the criteria
pollutant approach for developing DFs is appropriate. Using
CO2 as an example, many of the engine deterioration concerns
previously identified will affect CO2 emissions. Reduced
compression, as a result of wear, will cause higher fuel consumption
and increase CO2 production. In addition, as aftertreatment
devices age (primarily particulate traps), regeneration events may
become more frequent and take longer to complete. Since regeneration
commonly requires an increase in fuel rate, CO2 emissions
would likely increase as well. Finally, any changes in EGR levels will
affect heat release rates, peak combustion temperatures, and
completeness of combustion. Since these factors could reasonably be
expected to change fuel consumption, CO2 emissions would be
expected to change accordingly.
    HHD diesel engines may also require some degree of aftertreatment
maintenance throughout their useful life. For example, one major heavy-
duty engine manufacturer specifies that their diesel particulate
filters be removed and cleaned at intervals between 200,000 and 400,000
miles, depending on the severity of service. Another major engine
manufacturer requires servicing diesel particulate filters at 300,000
miles. This maintenance or lack thereof if service is neglected, could
have serious negative implications to CO2 emissions. In
addition, there may be emissions-related warranty implications for
manufacturers to ensure that if rebuilding or specific emissions
related maintenance is necessary, it will occur at the prescribed
intervals. Therefore, it is imperative that manufacturers are detailed
in their maintenance instructions. The agency currently seeks public
comment on how to properly address this issue.
    Lean-NOX aftertreatment devices may also facilitate GHG
reductions by allowing engines to run with higher engine-out
NOX levels in exchange for more efficient calibrations. In
most cases, these aftertreatment devices require a consumable
reductant, such as diesel exhaust fluid, which requires periodic
maintenance by the vehicle operator. Without such maintenance, the
emission control system may be compromised and compliance with emission
standards may be jeopardized. Such maintenance is considered to be
critical emission related maintenance and manufacturers must therefore
demonstrate that it is likely to be completed at the required
intervals. One example of such a demonstration is an engine power de-
rate strategy that will limit engine power or vehicle speed in absence
of this required maintenance.
    If the manufacturer determines that maintenance is necessary on
critical emission-related components within the useful life period,
they must have a reasonable basis for ensuring that this maintenance
will be completed as scheduled. This includes any adjustment, cleaning,
repair, or replacement of critical emission-related components.
Typically, the agency has only allowed manufacturers to schedule such
maintenance if the manufacturer can demonstrate that the maintenance is
reasonably likely to be done at the recommended intervals. This
demonstration may be in the form of survey data showing at least 80
percent of in-use engines get the prescribed maintenance at the correct
intervals. Another possibility is to provide the maintenance free of
charge. We see no reason to depart from this approach for GHG-related
critical emission-related components; however the agency welcomes
commentary on this approach.
(b) Demonstrating Compliance With the Proposed Standards
(i) CO2 Standards
    The final test results (adjusted for deterioration, if applicable)
form the basis for the Family Certification Limit (FCL), which the
manufacturer must specify to be at or above the certification test
results. This FCL becomes the emission standard for the family and any
certification or confirmatory testing must show compliance with this
limit. In addition, manufacturers may choose an FCL at any level above
their certified emission level to provide a larger compliance margin.
If subsequent certification or confirmatory testing reveals emissions
above the FCL, the new, higher result becomes the FCL.
    The FCL is also used to determine the Family Emission Limit (FEL),
which serves as the emission limit for any subsequent field testing
conducted after the time of certification. This would primarily include
selective enforcement audits, but also may include in-use testing and/
or production line testing for GHGs. The FEL differs from the FCL in
that it includes an EPA-defined compliance margin; currently proposed
to be 2 percent. Under this scenario the FEL would always be 2 percent
higher than the FCL.
 Engine Emission Testing
    Under current non-GHG engine emissions regulations, manufacturers
are required to demonstrate compliance using two test methods: The
heavy-duty transient cycle and the heavy-duty steady state test. Each
test is an engine speed versus engine torque schedule intended to be
run on an engine dynamometer. Over each test, emissions are sampled
using the equipment and procedures outlined in 40 CFR part 1065, which
includes provisions for measuring CO2, N2O, and
CH4. Emissions may be sampled continuously or in a batch
configuration (commonly known as ``bag sampling'') and the total mass
of emissions over each cycle are normalized by the engine power
required to complete the cycle. Following each test, a validation check
is made comparing actual engine speed and torque over the cycle to the
commanded values. If these values do not align well, the test is deemed
invalid.
    The transient Heavy-duty FTP cycle is characteristic of typical
urban stop-and-go driving. Also included is a period of more steady
state operation that would be typical of short cruise intervals at 45
to 55 miles per hour. Each transient test consists of two 20 minute
tests separated by a ``soak'' period of 20 minutes. The first test is
run with the engine in a ``cold'' state, which involves letting the
engine cool to ambient conditions either by sitting overnight or by
forced cooling provisions outlined in Sec.  86.1335-90 (or 40 CFR part
1036). This portion of the test is meant to assess the ability of the
engine to control emissions during the period prior to reaching normal
operating temperature. This is commonly a challenging area in criteria
pollutant emission control, as cold combustion chamber surfaces tend to
inhibit mixing and vaporization of

fuel and aftertreatment devices do not tend to function well at low
temperatures.
    Following the first test, the engine is shut off for a period of 20
minutes, during which emission analyzer checks are performed and
preparations are made for the second test (also known as the ``hot''
test). After completion of the second test, the results from the cold
and hot tests are weighted and a single composite result is calculated
for each pollutant. Based on typical in-use duty cycles, the cold test
results are given a \1/7\ weighting and the hot test results are given
a \6/7\ weighting. Deterioration factors are applied to the final
weighted results and the results are then compared to the emission
standards.
    Prior to 2007, compliance only needed to be demonstrated over the
Heavy-duty FTP. However, a number of events brought to light the fact
that this transient cycle may not be as well suited for engines which
spend much of their duty cycle at steady cruise conditions, such as
those used in line-haul semi-trucks. As a result, the steady-state SET
procedure was added, consisting of 13 steady-state modes. During each
mode, emissions were sampled for a period of five minutes. Weighting
factors were then applied to each mode and the final weighted results
were compared to the emission standards (including deterioration
factors). In addition, emissions at each mode could not exceed the NTE
emission limits. Alternatively, manufacturers could run the test as a
ramped-modal cycle. In this case, the cycle still consists of the same
speed/torque modes, however linear progressions between points are
added and instead of weighting factors, each mode is sampled for
various amounts of time. The result is a continuous cycle lasting
approximately 40 minutes. With the implementation of part 1065 test
procedures in 2010, manufacturers are now required to run the modal
test as a ramped-modal cycle. In addition, the order of the speed/
torque modes in the ramped-modal cycle have changed for 2010 and later
engines.
    It is well known that fuel consumption, and therefore
CO2 emissions, are highly dependent on the drive cycle over
which they are measured. Steady cruise conditions, such as highway
driving, tend to be more efficient, having lower fuel consumption and
CO2 emissions. In contrast, highly transient operation, such
as city driving, tends to lead to lower efficiency and therefore higher
fuel consumption and CO2 emissions. One example of this is
the difference between EPA-measured city and highway fuel economy
ratings assigned to all new light-duty passenger vehicles.
    For this heavy-duty engine and vehicle proposal, we believe it is
important to assess CO2 emissions and fuel consumption over
both transient and steady state test cycles, as all vehicles will
operate in conditions typical of each cycle at some point in their
useful life. However, due to the drive cycle dependence of
CO2 emissions, we do not believe it is reasonable to have a
single CO2 standard which must be met for both cycles. A
single CO2 standard would likely prove to be too lax for
steady-state conditions while being too strict for transient
conditions. Therefore, the agencies are recommending that all heavy-
duty engines be tested over both transient and steady-state tests.
However, only the results from either the transient or steady-state
test cycles would be used to assess compliance with GHG standards,
depending on the type of vehicle in which the engine will be used.
Engines that will be used in Class 7 and 8 tractors would use the
ramped-modal cycle for GHG certification, and engines used in
vocational vehicles would use the Heavy-duty FTP cycle. In both cases,
results from the other test cycle would be reported but not used for a
compliance decision. Engines will continue to be required to show
criteria pollutant compliance over both cycles, in addition to NTE
requirements.
    The agencies propose that manufacturers submit both composite data
sets, as well as modal data for criteria and GHG pollutants for engine
certification. This would include submission of discrete mode results
from the continuous analyzer data collected during the ramped-modal
cycle test. This would also include providing both cold start and hot
start transient heavy-duty FTP emissions results, as well as the
composite emissions at the time of certification. In an effort to
improve the accuracy of the simulation model being used for assessing
CO2 and fuel consumption performance and overall engine
emissions performance, gaseous pollutants sampled using continuous
analyzers (including but not limited to emissions results for
CO2, CO, and NOX) would need to provide the
constituent data from each of the test modes. The agencies welcome
comment on this proposed requirement. As explained above in Section II,
the agencies are proposing an alternative standard whereby
manufacturers may elect that certain of their engine families meet an
alternative percent reduction standard, measured from the engine
family's 2011 baseline, instead of the main 2014 MY standard. As part
of the certification process, manufacturers electing this standard
would not only have to notify the agency of the election but also
demonstrate the derivation of the 2011 baseline CO2 emission
level for the engine family. Manufacturers would also have to
demonstrate that they have exhausted all credit opportunities.
Durability Testing
    Another element of the current certification process is the
requirement to complete durability testing to establish DFs. As
previously mentioned, manufacturers are required to demonstrate that
their engines comply with emission standards throughout the regulatory
compliance period of the engine. This demonstration is commonly made
through the combination of low-hour test results and testing based
deterioration factors.
    For engines without aftertreatment devices, deterioration factors
primarily account for engine wear as service is accumulated. This
commonly includes wear of valves, valve seats, and piston rings, all of
which reduce in-cylinder pressure. Oil control seals and gaskets also
deteriorate with age, leading to higher lubricating oil consumption.
Additionally, flow properties of EGR systems may change as deposits
accumulate and therefore alter the mass of EGR inducted into the
combustion chamber. These factors, amongst others, may serve to reduce
power, increase fuel consumption, and change combustion properties; all
of which affect pollutant emissions.
    For engines equipped with aftertreatment devices, DFs take into
account engine deterioration, as described above, in addition to aging
affects on the aftertreatment devices. Oxidation catalysts and other
catalytic devices rely on active precious metals to effectively convert
and reduce harmful pollutants. These metals may become less active with
age and therefore pollutant conversion efficiencies may decrease.
Particulate filters may also experience reduced trapping efficiency
with age due to ash accumulation and/or degradation of the filter
substrate, which may lead to higher tailpipe PM measurements and/or
increased regeneration frequency. If a pollutant is predominantly
controlled by aftertreatment, deterioration of emission control depends
on the continued operation of the aftertreatment device much more so
than on consistent engine-out emissions.
    At this time, we anticipate that most engine component wear will
not have a significant negative impact on CO2 emissions.
However, wear and aging of

aftertreatment devices may or may not have a significant negative
impact on CO2 emissions. In addition, future engine or
aftertreatment technologies may experience significant deterioration in
CO2 emissions performance over the useful life of the
engine. For these reasons, we believe that the use of DFs for
CO2 emissions is both appropriate and necessary. As with
criteria pollutant emissions, these DFs are preferably developed
through testing the engine over a representative duty cycle for an
extended period of time. This is typically either half or full useful
life, depending on the regulatory class. The DFs are then calculated by
comparing the high-hour to low-hour emission levels, either by division
or subtraction (for multiplicative & additive DFs, respectively).
    This testing process may be a significant cost to an engine
manufacturer, mainly due to the amount of time and resources required
to run the engine out to half or full useful life. For this reason,
durability testing for the determination of DFs is not commonly
repeated from model year to model year. In addition, some DFs may be
allowed to carry over between families sharing a common architecture
and aftertreatment system. EPA prefers to have manufacturers develop
testing-based DFs for their products, and we are proposing that this be
the case for the final rule. However, we do understand that for the
reasons stated above, it may be impractical to expect manufacturers to
have testing-based deterioration factors available for this proposal.
Therefore, we are willing to consider requiring the use of assigned DFs
for CO2. Under this possibility, we suggest that
manufacturers would be required to submit any CO2 data from
durability testing to aid in developing more accurate assigned DFs.
IRAFs/Regeneration Impacts on CO2
    Heavy-duty engines may be equipped with exhaust aftertreatment
devices which require periodic ``regeneration'' to return the device to
a nominal state. A common example is a diesel particulate filter, which
accumulates PM as the engine is operated. When the PM accumulation
reaches a threshold such that exhaust backpressure is significantly
increased, exhaust temperature is actively increased to oxidize the
stored PM. The increase in exhaust temperature is commonly facilitated
through late combustion phasing and/or raw fuel injection into the
exhaust system upstream of the filter. Both methods impact emissions
and therefore must be accounted for at the time of certification. In
accordance with Sec.  86.004-28(i), this type of event would be
considered infrequent because in most cases they only occur once every
30 to 50 hours of engine operation (rather than once per transient test
cycle), and therefore adjustment factors must be applied at
certification to account for these effects.
    Similar to DFs, these adjustment factors are based off of
manufacturer testing; however this testing is far less time consuming.
Emission results are measured from two test cycles: With and without
regeneration occurring. The differences in emission results are used,
along with the frequency at which regeneration is expected to occur, to
develop upward and downward adjustment factors. Upward adjustment
factors are added to all emission results derived from a test cycle in
which regeneration did not occur. Similarly, downward adjustment
factors are subtracted from results based on a cycle which did
experience a regeneration event. Each pollutant will have a unique set
of adjustment factors and additionally, separate factors are commonly
developed for transient and steady-state test cycles.
    The impact of regeneration events on criteria pollutants varies by
pollutant and the aftertreatment device(s) used. In general, the
adjustment factor can have a very significant impact on compliance with
the NOX standard. For this reason, heavy-duty vehicle and
engine manufacturers are already very well motivated to extend the
regeneration frequency to as long an interval as possible and to reduce
the regeneration as much as possible. Both of these actions
significantly reduce the impact of regeneration on CO2
emissions and fuel consumption. We do not believe that adding an
adjustment factor for infrequent regeneration to the CO2 or
fuel efficiency standards would provide a significant additional
motivation for manufacturers to reduce regenerations. Moreover, doing
so would add significant and unnecessary uncertainty to our projections
of CO2 and fuel consumption performance in 2014 and beyond.
In addressing that uncertainty, the agencies would have to set less
stringent fuel efficiency and CO2 standards for heavy-duty
trucks and engines. Therefore, we are not proposing to include an
infrequent regeneration adjustment factor for CO2 or fuel
efficiency in this program. The agencies are seeking public commentary
on this approach.
Auxiliary Emission Control Devices
    As part of the engine control strategy, there may be devices or
algorithms which reduce the effectiveness of emission control systems
under certain limited circumstances. These strategies are referred to
as Auxiliary Emission Control Devices (AECDs). One example would be the
reduced use of EGR during cold engine operation. In this case, low
coolant temperatures may cause the electronic control unit to reduce
EGR flow to improve combustion stability. Once the engine warms up,
normal EGR rates are resumed and full NOX control is
achieved.
    At the time of certification, manufacturers are required to
disclose all AECDs and provide a full explanation of when the AECD is
active, which sensor inputs effect AECD activation, and what aspect of
the emission control system is affected by the AECD. Manufacturers are
further required to attest that their AECDs are not ``defeat-devices,''
which are intentionally targeted at reducing emission control
effectiveness.
    Several common AECDs disclosed for criteria pollutant certification
will have a similarly negative influence on GHG emissions as well. One
such example is cold-start enrichment, with provides additional fueling
to stabilize combustion shortly after initially starting the engine.
From a criteria pollutant perspective, HC emissions can reasonably be
expected to increase as a result. From a GHG perspective, the extra
fuel does not result in a similar increase in power output and
therefore the efficiency of the engine is reduced, which has a negative
impact on CO2 emissions. In addition, there may be AECDs
that uniquely reduce GHG emission control effectiveness. Therefore,
consistent with today's certification procedures, we are proposing that
a comprehensive list of AECDs covering both criteria pollutant, as well
as GHG emissions is required at the time of certification.
(ii) EPA's N2O and CH4 Standards
    In 2009, EPA issued rules requiring manufacturers of mobile-source
engines to report the emissions of CO2, N2O, and
CH4 (74 FR 56260, October 30, 2009). While CO2 is
commonly measured during certification testing, CH4 and
N2O are not. CH4 has traditionally not been
included in criteria pollutant regulations because it is a relatively
stable molecule and does not contribute significantly to ground-level
ozone formation. In addition, N2O is commonly a byproduct of
lean-NOX aftertreatment systems. Until recently, these types
of systems were not widely used on heavy-duty engines and therefore
N2O emissions were insignificant. Both species, while
emitted in small quantities relative to

CO2, have much higher global warming potential than
CO2 and therefore must be considered as part of a
comprehensive GHG regulation.
    EPA is proposing that CH4 and N2O be reported
at the time of certification. We are proposing to allow manufacturers
to use a compliance statement based on good engineering judgment for
the first year of the program in lieu of direct measurement of
N2O. However, beginning in the 2015 model year, the agency
is proposing to require the direct measurement of N2O for
certification. The intent of the CH4 and N2O
standards are more focused on prevention of future increases in these
compounds, rather than forcing technologies that reduce these
pollutants. As one example, we envision manufacturers satisfying this
requirement by continuing to use catalyst designs and formulations that
appropriately control N2O emissions rather than pursuing a
catalyst that may increase N2O. In many ways this becomes a
design-based criterion in that the decision of one catalyst over
another will effectively determine compliance with N2O
standards over the useful life of the engine. As noted in Section II
above, 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. We are therefore asking for comment on this subject.
(c) Additional Compliance Provisions
(i) Warranty & Defect Reporting
    Under section 207 of the CAA, engine manufacturers are required to
warrant that their product is free from defects that would cause the
engine to not comply with emission standards. This warranty must be
applicable from when the engine is introduced into commerce through a
period generally defined as half of the regulatory useful life
(specified in hours and years, whichever comes first). The exact time
of this warranty is dependent on the regulatory class of the engine. In
addition, components that are considered ``high cost'' are required to
have an extended warranty. Examples of such components would be exhaust
aftertreatment devices and electronic control units.
    Current warranty provisions in 40 CFR part 86 define the warranty
periods and covered components for heavy-duty engines. The current list
of components is comprised of any device or system whose failure would
result in an increase in criteria pollutant emissions. At this point,
we believe this list to be adequate for addressing GHG emissions as
well. However, there may be instances where the failure of a component
or system may reduce the efficiency of the engine while not increasing
criteria pollutant emissions. In this case, the component or system may
be inappropriately left off the list of covered components. Therefore
we are seeking public comment on what devices and/or systems may need
to be added to the warranted component list to adequately address GHG
emissions. The following list identifies items commonly defined as
critical emission-related components:
     Electronic control units.
     Aftertreatment devices.
     Fuel metering components.
     EGR-System components.
     Crankcase-ventilation valves.
     All components related to charge-air compression and
cooling.
     All sensors and actuators associated with any of these
components.
    When a manufacturer experiences an elevated rate of failure of an
emission control device, they are required to submit defect reports to
the EPA. These reports will generally have an explanation of what is
failing, the rate of failure, and any possible corrections taken by the
manufacturer. Based on how successful EPA believes the manufacturer to
be in addressing these failures, the manufacturer may need to conduct a
product recall. In such an instance, the manufacturer is responsible
for contacting all customers with affected units and repairing the
defect at no cost to them. We believe this structure for the reporting
of criteria pollutant defects, and recalls, is appropriate for
components related to complying with GHG emissions as well.
(ii) Maintenance
    Engine manufacturers are required to outline maintenance schedules
that ensure their product will remain in compliance with emission
standards throughout the useful life of the engine. This schedule is
required to be submitted as part of the application for certification.
Maintenance that is deemed to be critical to ensuring compliance with
emission standards is classified as ``critical emission-related
maintenance.'' Generally, manufacturers are discouraged from specifying
that critical emission-related maintenance is needed within the
regulatory useful life of the engine. However, if such maintenance is
unavoidable, manufacturers must have a reasonable basis for ensuring it
is performed at the correct time. This may be demonstrated through
several methods including survey data indicating that at least 80% of
engines receive the required maintenance in-use or manufacturers may
provide the maintenance at no charge to the user. During durability
testing of the engine, manufacturers are required to follow their
specified maintenance schedule.
    Maintenance relating to components relating to reduction of GHG
emissions are not expected to present unique challenges. Therefore, we
are not proposing any changes to the provisions for the specification
of emission-related maintenance as outlined in 40 CFR part 86.
(2) Proposed Enforcement Provisions
(a) Emission Control Information Labels
    Current provisions for engine certification require manufacturers
to equip their product with permanent emission control information
labels. These labels list important characteristics, parameters, and
specifications related to the emissions performance of the engine.
These include, but are not limited to, the manufacturer, model,
displacement, emission control systems, and tune-up specifications. In
addition, this label also provides a means for identifying the engine
family name, which can then be referenced back to certification
documents. This label provides essential information for field
inspectors to determine that an engine is in fact in the certified
configuration.
    We do not anticipate any major changes needing to be made to
emission control information labels as a result of new GHG standards
and a single label is appropriate for both criteria pollutant and GHG
emissions purposes. Perhaps the most significant addition would be the
inclusion of Family Certification Levels or Family Emission Limits for
GHG pollutants, if the manufacturer is participating in averaging,
banking, and trading. In addition, the label will need to indicate
whether the engine is certified for use in vocational vehicles,
tractors, or both.
(b) In-Use Standards
    In-use testing of engines provides a number of benefits for
ensuring useful life compliance. In addition to verifying compliance
with emission standards at any given point in the useful life, it can
be used along with manufacturer defect reporting, to indentify
components failing at a higher than normal rate. In this case, a
product recall or other service campaign can be initiated and the
problem can be rectified. Another key benefit of in-use testing is the
discouragement of control strategies

catered to the certification test cycles. In the past, engine
manufacturers were found to be producing engines that performed
acceptably over the certification test cycle, while changing to
alternate operating strategies ``off-cycle'' which caused increases in
criteria pollutant emissions. While these strategies are clearly
considered defeat devices, in-use testing provides a meaningful way of
ensuring that such strategies are not active under normal engine
operation.
    Currently, manufacturers of certified heavy-duty engines are
required to conduct in-use testing programs. The intent of these
programs is to ensure that their products are continuing to meet
criteria pollutant emission standards at various points within the
useful life of the engine. Since initial certification is based on
engine dynamometer testing, and removing in-use engines from their
respective vehicles is often impractical, a unique testing procedure
was developed. This includes using portable emission measurement
systems (PEMS) and testing the engine over typical in-situ drive routes
rather than a prescribed test cycle. To assess compliance, emission
results from a well defined area of the speed/torque map of the engine,
known as the NTE zone, are compared to the emission standards. To
account for potential increases in measurement and operational
variability, certain allowances are applied to the standard which
results in the standard for NTE measurements (NTE limit) to be at or
above the duty cycle emission standards.
    In addition, EPA also conducts an annual in-use testing program of
heavy-duty engines. Testing procured vehicles with specific engines
over well-defined drive routes using a constant trailer load allows for
a consistent comparison of in-use emissions performance. If potential
problems are identified in-situ, the engine may be removed from the
vehicle and tested using an engine dynamometer over the certification
test cycles. If deficiencies are confirmed the agency will either work
with the manufacturer to take corrective action or proceed with
enforcement action against the manufacturer.
    The GHG reporting rule requires manufacturers to submit
CO2 data from all engine testing (beginning in the 2011
model year), which we believe is equally applicable to in-use
measurements. Methods of CO2 in-situ measurement are well
established and most, if not all, PEMS devices measure and record
CO2 along with criteria pollutants. CH4 and
N2O present in-situ measurement challenges that may be
impractical to overcome for this testing, and therefore it is not
recommended that they be included in in-use testing requirements at
this time. While measurement of CO2 may be practical and
important, implementing an NTE emission standard for CO2 is
challenging. As previously discussed, CO2 emissions are
highly dependent on the drive cycle of the vehicle, which does not lend
itself well to the NTE-based test procedure. Therefore, we propose that
manufacturers be required to submit CO2 data from in-use
testing, in both g/bhp-hr and g/ton-mile, but these data will be used
for reference purposes only (there would be no NTE limit/standard for
CO2).
(3) Other Certification Provisions
(a) Carryover/Carry Across Certification Test Data
    EPA's current certification program for heavy-duty engines allows
manufacturers to carry certification test data over and across
certification testing from one model year to the next, when no
significant changes to models are made. EPA is proposing to also apply
this policy to CO2, N2O and CH4
certification test data.
(b) Certification Fees
    The CAA allows EPA to collect fees to cover the costs of issuing
certificates of conformity for the classes of engines covered by this
proposal. On May 11, 2004, EPA updated its fees regulation based on a
study of the costs associated with its motor vehicle and engine
compliance program (69 FR 51402). At the time that cost study was
conducted, the current rulemaking was not considered. At this time the
extent of any added costs to EPA as a result of this proposal is not
known. EPA will assess its compliance testing and other activities
associated with the rule and may amend its fees regulations in the
future to include any warranted new costs.
(c) Onboard Diagnostics
    Beginning in the 2013 model year, manufacturers will be required to
equip heavy-duty engines with on-board diagnostic systems. These
systems monitor the activity of the emission control system and issue
alerts when faults are detected. These diagnostic systems are currently
being developed based around components and systems that influence
criteria pollutant emissions. Consistent with the light-duty vehicle
GHG rule, we believe that monitoring of these components and systems
for criteria pollutant emissions will have an equally beneficial effect
on CO2 emissions. Therefore, we do not anticipate the
necessity of having any unique onboard diagnostic provisions for heavy-
duty GHG emissions. We are seeking comment on this topic, however.
(d) Applicability of Current High Altitude Provisions to Greenhouse
Gases
    EPA is proposing that engines covered by this proposal must meet
CO2, N2O and CH4 standards at elevated
altitudes. The CAA requires emission standards under section 202 for
heavy-duty engines to apply at all altitudes. EPA does not expect
engine CO2, CH4, or N2O emissions to
be significantly different at high altitudes based on engine
calibrations commonly used at all altitudes. Therefore, EPA proposes
that it retain its current high altitude regulations so manufacturers
will not normally be required to submit engine CO2 test data
for high altitude. Instead, they will be required to submit an
engineering evaluation indicating that common calibration approaches
will be utilized at high altitude. Any deviation in emission control
practices employed only at altitude will need to be included in the
AECD descriptions submitted by manufacturers at certification. In
addition, any AECD specific to high altitude will be required to
include emissions data to allow EPA evaluate and quantify any emission
impact and validity of the AECD.
(e) Emission-Related Installation Instructions
    Engine manufacturers are currently required to provide detailed
installation instructions to vehicle manufacturers. These instructions
outline how to properly install the engine, aftertreatment, and other
supporting systems, such that the engine will operate in its certified
configuration. At the time of certification, manufacturers may be
required to submit these instructions to EPA to verify that sufficient
detail has been provided to the vehicle manufacturer.
    We do not anticipate any major changes to this documentation as a
result of regulating GHG emissions. The most significant impact will be
the addition of language prohibiting vehicle manufacturers from
installing engines into vehicle categories in which they are not
certified for. An example would be a tractor manufacturer installing an
engine certified for only vocational vehicle use. Explicit instructions
on behalf of the engine manufacturer that such acts are prohibited will
serve as sufficient notice to the vehicle manufacturers and failure to
follow

such instructions will in the vehicle manufacturer being in non-
compliance.
(f) Alternate CO2 Emission and Fuel Consumption Standards
    Under the proposed rule, engine manufacturers have the option of
certifying to CO2 emission and fuel consumption standards
that are 5 percent below a baseline value established from their 2011
model-year products. If a manufacturer elects to participate in this
program they must indicate this on their certification application. In
addition, sufficient details must be submitted regarding the baseline
engine such that the agency can verify that the correct optional
CO2 emission and fuel consumption standards have been
calculated. This data will need to include the engine family name of
the baseline engine, so references to the original certification
application can be made, as well as test data showing the
CO2 emissions and fuel consumption of the baseline engine.

D. Class 7 and 8 Combination Tractors

(1) Proposed Compliance Approach
    In addition to requiring engine manufacturers to certify their
engines, manufacturers of Class 7 and 8 combination tractors must also
certify that their vehicles meet the proposed CO2 emission
and fuel consumption standards. This vehicle certification will ensure
that efforts beyond just engine efficiency improvements are undertaken
to reduce GHG emissions and fuel consumption. Some examples include
aerodynamic improvements, rolling resistance reduction, idle reduction
technologies, and vehicle speed limiting systems.
    Unlike engine certification however, this certification would be
based on a load-specific basis (g/ton-mile or gal/1,000 ton-mile as
opposed to work-based, or g/bhp-hr). This would take into account the
anticipated vehicle loading that would be experienced in use and the
associated affects on fuel consumption and CO2 emissions.
Vehicle manufacturers would also be required to warrant their products
against emission defects, and demonstrate that a service network is in
place to correct any such conditions. The vehicle manufacturer also
bears responsibility in the event that an emission-related recall is
necessary.
(a) Certification Process
    In order to obtain a certificate of conformity for the tractor,
vehicle manufacturers would complete a compliance demonstration,
showing that their product meets emission standards as well as other
regulatory requirements. For purposes of this demonstration, vehicles
with similar emission characteristics throughout their useful life are
grouped together in test groups, similar to EPA's light-duty emissions
certification program. Examples of characteristics that would define a
test group for heavy-duty vehicles are wheel and tire package,
aerodynamic profile, tire rolling resistance, and engine model. Under
this system, the worst-case vehicle would be selected based on having
the highest fuel consumption, and all other models within the family
are assumed to have emissions and fuel consumption at or below the
parent model and therefore in compliance with CO2 emission
and fuel consumption standards. Any vehicle within the family can be
subject to selective enforcement auditing in addition to confirmatory
or other administrator testing.
    We anticipate test groups for Class 7 and 8 combination tractors to
utilize the standardized 12-digit naming convention, as outlined in the
engine certification section of this chapter. As with engines, each
certifying vehicle manufacturer will have a unique three digit code
assigned to them. Currently, there is no 5th digit (industry sector)
code for this class of vehicles, for which we propose to use the next
available character, ``2.'' Since we are proposing that the engine is
one of several test-group defining features, we still believe it is
appropriate to include engine displacement in the family name. If the
test-group consists includes multiple engine models with varying
displacements, the largest would be specified in the test-group name,
consistent with current practices. The remaining characters would
remain available for California ARB and/or manufacturer use, such that
the result is a unique test-group name.
    Class 7 and 8 tractors share several common traits, such as the
trailer attachment provisions, number of wheels, and general
construction. However, further inspection reveals key differences
related to GHG emissions. Payloads hauled by Class 7 tractors are
significantly less than Class 8 tractors. In addition, Class 8 vehicles
may have provisions for hoteling (``sleeper cabs''), which results in
an increase in size as well as the addition of comfort features like
power and climate control for use while the truck is parked. Both
segments may have various degrees of roof fairing to provide better
aerodynamic matching to the trailer being pulled. This is a feature
which can help reduce CO2 emissions significantly when
properly matched to the trailer, but can also increase CO2
emissions if improperly matched. Based on these differences, it is
reasonable to expect differences in CO2 emissions, and
therefore these properties form the basis for the proposed combination
tractor regulatory subcategories.
    The various combinations of payload, cab size, and roof profile
result in nine proposed regulatory subcategories for Class 7 and 8
trucks. These include Class 7 (day cabs), Class 8 (day cabs), and Class
8 (sleeper cabs), each with high, mid, and low roof profiles. The Class
7 tractors would have a regulatory useful life of 185,000 miles while
Class 8 tractors would have a regulatory life of 435,000 miles and must
meet CO2 emission standards throughout this period.
(b) Demonstrating Compliance With the Proposed Standards
(i) CO2 and Fuel Consumption Standards
    Consistent with existing certification processes for light-duty
vehicles and heavy-duty pickups and vans, emissions testing of the
complete vehicle would be the preferred method for demonstrating
compliance with vehicle emission standards. However, vehicle-level
certification is new to the heavy-duty vehicle segment above 14,000 lb.
Therefore, most vehicle manufacturers are not adequately equipped to
conduct vehicle-level emission testing for Class 7 and 8 combination
tractors. Chassis dynamometers, emission sampling equipment, and staff
engineering support are a few of the factors that would add significant
cost to vehicle development in a relatively short amount of time, which
may make the prospect of vehicle testing quite onerous. In addition to
the infrastructure and testing facilities the industry would need to
add, the agencies have not completed the extensive work ultimately
desirable for us to propose new test procedures and standards based on
the use of a chassis test procedure. Moreover, as explained in Section
II.C, because of the enormous numbers of truck configurations that have
an impact on fuel consumption, we do not believe that it would be
reasonable, at least initially, to require testing of many combinations
of tractor model configurations on a chassis dynamometer. Recognizing
these constraints related to time, staffing, and capital, we are
proposing only a vehicle simulation model option for demonstrating
compliance at the time of certification. However, we do believe that a
chassis based test procedure as

currently utilized for vehicles below 14,000 pounds could be a better
long-term approach to regulate all heavy-duty vehicles and we are
seeking comment on a chassis based approach.
Model
    Vehicle modeling will be conducted using the agencies' simulation
model, GEM, which is described in detail in Chapter 4 of the draft RIA.
Basically, this model functions by defining a vehicle configuration and
then exercises the model over various drive cycles. Several
initialization files are needed to define a vehicle, which include
mechanical attributes, control algorithms, and driver inputs. The
majority of these inputs will be predetermined by EPA and NHTSA for the
purposes of vehicle certification. The net results from GEM are
CO2 emissions and fuel consumption values over the proposed
drive cycles. The CO2 emission result will be used for