any CH4 emissions above the cap by taking steps to further
reduce CO2. Separately, EPA is finalizing to set standards
to control the leakage of HFCs from air conditioning systems.
    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
requirement).\306\ These rules will use the same testing procedures
already required for heavy-duty chassis certification, namely the
Light-duty FTP and the HFET. Using the data from these two tests, EPA
and NHTSA will compare the CO2 emissions and fuel
consumption results against the attribute-based target. The attribute
upon which the CO2 standard is based is a function of
vehicle payload, vehicle towing capacity and two-wheel versus four-
wheel drive configuration. The attribute-based standard targets will be
used to determine a manufacturer fleet standard. As discussed in
section IV above, manufacturers may use the ABT program and other
flexibilities in achieving and demonstrating compliance.
---------------------------------------------------------------------------

    \306\ Diesel engines are engine-certified with the option to
chassis certification Federally and for California.
---------------------------------------------------------------------------

    These rules will generally require complete HD pickups and vans to
have 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. Manufacturers will be allowed to
exclude vehicles they sell to secondary manufacturers as incomplete
vehicles, unless these vehicles are chassis-certified for criteria
(non-GHG) pollutants. To the extent manufacturers are allowed to
engine- or chassis-certify for criteria pollutant requirements today,
they will be allowed to continue to do so under the final regulations.
See subsection V.B(1)(e) for discussion of special provisions for
chassis-certification to GHG and fuel consumption standards.
    Because this program 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 will apply most of those
subpart S regulatory provisions to heavy-duty pickup trucks and vans
and not recodify them in the new part 1037. Most of the new part 1037
thus 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.
Similarly NHTSA's requirements for these vehicles in Sec.  535.6(a) are
based on 40 CFR part 86.
(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
certification is required for each model year.\307\
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    \307\ CAA Section 206(a)(1).
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    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.\308\
---------------------------------------------------------------------------

    \308\ 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 light-duty
vehicle GHG compliance program.
    These rules will 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 the agencies will
integrate this new vehicle certification program into the existing
certification program.
    An integrated approach with NHTSA has been undertaken to allow
manufacturers a single point of entry to address certification and
compliance. Vehicle manufacturers will initiate the formal
certification process with their submission of application for a
certificate of conformity to EPA, similar to the light-duty program.
(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/evaporative family combination. 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.\309\
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    \309\ 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).
---------------------------------------------------------------------------

    This program will retain the current test group structure for
heavy-duty

pickups and vans in the certification requirements for CO2
and fuel consumption. At the time of certification, manufacturers will
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 will generally be allowed for
compliance with the fleet average CO2 and fuel consumption
standards as described below. EPA's issuance of a certificate will 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)). The new
regulations we are adopting will not change these existing EPA
certification options for complete (or incomplete) HD vehicles. EPA
recognizes that the existing heavy-duty chassis test group criteria do
not necessarily relate to CO2 emission levels. See 75 FR
25472 (addressing the same issue for light-duty vehicles). 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.\310\ Most important among these may be vehicle weight,
horsepower, aerodynamics, vehicle size, and performance features. To
remedy this, EPA will allow manufacturers provisions that are similar
to the light-duty vehicle rule that would yield more accurate
CO2 estimates than only using the test group emission data
vehicle CO2 emissions.
---------------------------------------------------------------------------

    \310\ 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 will determine if this approach is adequate
method for N2O and CH4 emissions compliance or if
testing on additional vehicles is required to ensure their entire fleet
meets 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 allowing the use of a single
Emission Data Vehicle to represent the test group for both criteria
pollutant and CO2 certification. The manufacturer will 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 will 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 will become the official
certification test results (as per the conditioned certificate) and
will be used to determine compliance with the fleet average. If the
test vehicle is in fact the worst case CO2 vehicle for the
test group, the manufacturer may elect to apply the Emission Data
Vehicle emission levels to all models in the test group for purposes of
calculating fleet average emissions. Manufacturers may 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, in order to better represent the
improved performance of vehicles within a test group other than the
Emission Data Vehicle, will necessarily increase testing burden beyond
the minimum EDV testing.
    As explained in earlier Sections, there are two standards that the
manufacturer will 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. To address commenter concerns
regarding test variability due to facility and build variation for each
model, the in-use and SEA standards are set at 10 percent higher than
the level used for that model in calculating the fleet average. The
certificate covers both of the fleet and in-use 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) Demonstrating Compliance

(i) CO2 and Fuel Consumption Fleet Standards

    As noted, attribute-based CO2 and fuel consumption
standards result in each manufacturer having fleet average
CO2 and fuel consumption standards unique to its heavy-duty
truck fleet of GVWR between 8,500-14,000 pounds and that standard will
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 final attributes used
to determine the stringency of the CO2 and fuel consumption
standards are payload and towing capacity as described in Section II.
Generally, fleets with a mix of vehicles with increased payloads or
greater towing capacity (or utilizing four wheel drive configurations)
will face numerically less stringent standards (i.e., higher
CO2 grams/mile standards or fuel consumption gallons/100
miles standards) than fleets consisting of less powerful vehicles.
(However, the standards will 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 will be based on the final model year production figures. A
manufacturer's calculation of fleet average emissions and fuel
consumption at the end of the model year will be based on the
production-weighted average emissions and fuel consumption of each
model in its fleet. The payload and towing capacity inputs used to
determine manufacturer compliance will be the advertised values.
    The agencies will 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 will be able to test, and possibly model, more
configurations of vehicles than were historically possible. 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 allowing the use of ADFE similar to that allowed for
light-duty vehicles in 40 CFR 600.006-08(e). Some commenters, including
the American Automotive Policy Council, were concerned that adopting
the light-duty ADFE program with its current minimum test requirements
would unduly increase testing burden. In addition to concerns over
implementing the light-duty ADFE program for heavy-duty GHG compliance,
commenters noted the need to develop a new HD ADFE methodology that
addressed unique HD concerns. EPA and NHTSA have continued to work with
stakeholders to address the above concerns with using a modified LD
ADFE program. To address these concerns, the agencies will expand the
allowed use of ADFE beyond that which is allowed in the LD program.
Since ADFE equations are not final at the time of this action, updates
to the HD ADFE program will be made through guidance or future
rulemaking. 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 are 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. See generally 75 FR at 25472.
    NHTSA and EPA are not adopting the CREE methodology for HD pickups
and vans, and so will not 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 rulemaking 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 finalizing. Finally, it would add complexity
to the program with little real world benefit.
(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
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).
    An in-use program was already set forth in the light-duty 2012-2016
MY vehicle rule similar to the heavy-duty pickups and vans. The In-Use
Verification Program for heavy-duty pickups and vans will follow the
same general provisions of the light-duty program in regard to testing,
vehicle selection, and reporting. See 75 FR 25474-25476.
(d) Special Provisions for Chassis Certification
    We proposed to include most cab-chassis Class 2b and 3 vehicles
(vehicles sold as incomplete vehicles with the cab substantially in
place but without the primary load-carrying enclosure) 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 proposed to treat these vehicles as equivalent to the
complete van or truck product from which they are derived. 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 ``sister'' vehicle. See 75 FR at 74263.
    Commenters opposed this proposed requirement for a number of
reasons: (1) It would have the unintended consequence of dual
certification for some of these vehicles--engine certification for
criteria pollutants and vehicle certification for GHGs, and vice-versa
for some other vehicles, (2) it would be of modest benefit because most
of these cab-chassis vehicles would receive the desired aerodynamic and
other non-engine improvements even without chassis certification, in
virtue of their derivation from complete vehicles, and (3) a readily-
identifiable sister vehicle may not exist in every case. Based on the
comments, the agencies have re-evaluated the proposed approach for cab-
chassis certification and are restructuring our compliance approach to
provide significantly more flexibility while still ensuring comparable
or better GHG and fuel consumption performance overall.
    We are not requiring that cab-chassis vehicles be chassis-
certified, but are retaining chassis-certification for them as an
option using the proposed sister vehicle concept. We are instead
requiring that vehicles that are chassis-certified for criteria
pollutants be chassis-certified for GHGs and fuel consumption, and
likewise that vehicles with engines certified for criteria pollutants
(which in this case would be engines installed in vocational vehicles
exclusively) be certified to the vocational vehicle standards for GHGs
and fuel consumption, with minor exceptions detailed below. We believe
that this approach involving consistent chassis- and engine-
certification for criteria pollutants and GHGs is the most sensible way
to structure a program to minimize both the testing burden and the
potential for gaming.
    We are allowing use of the sister vehicle concept for incomplete
vehicle certification to include the selection of sister vehicles not
actually produced for sale by the certifying manufacturer. For the
great majority of vehicles this will not be an issue because the sister
vehicle will obviously be the complete pickup truck or van from which
the cab-chassis vehicle is derived. However if

the complete sister vehicle ceases production but the corresponding
incomplete vehicle does not, a manufacturer may continue to use the
sister vehicle emissions data through the carryover process that is
already practiced today. If carryover is not appropriate because of,
for example, an emissions-impacting recalibration of the engine, the
manufacturer may conduct new emissions testing using the coastdown data
collected on the original sister vehicle. This would still save
substantial effort without sacrificing data quality because coastdowns
are rather resource-intensive but are not much affected by engine
changes. Another potentially inappropriate situation would exist where
no sister vehicle exists because the manufacturer does not sell a
related complete vehicle. In this case, the manufacturer may coastdown
a mocked-up vehicle made from its incomplete vehicle and an added open
or closed cargo box that simulates a complete van or pickup truck, or
may coastdown one of its customers' completed vehicles.
    EPA and NHTSA requested comment on whether Class 4 vehicles that
are very similar to complete Class 3 pickup truck models should be
chassis-certified and regulated as part of the HD pickup and van
category, instead of as vocational vehicles. Commenters argued
convincingly that there are a number of important differences between
the Class 4 and Class 3 trucks that make such regulation inappropriate
as a general matter. As a result, we are keeping Class 4 trucks in the
vocational vehicle category. However, we are adding an optional
provision that allows manufacturers to certify Class 4 or 5 (14,001 to
19,500 lb GVWR) complete or incomplete vehicles to GHG and fuel
consumption standards, in the same way as Class 2b and 3 vehicles, and
thus be included within the Class 2b/3 fleet average. The engines in
these vehicles will continue to be engine-certified for criteria
pollutants, but the manufacturers could include the vehicles in their
fleet average standard and annual compliance calculations, using the
same certification and compliance provisions as for the smaller
vehicles, including the equations for determining work factors and
target standards, in-use requirements, reporting requirements, credit
generation and use, and sister vehicle provisions for incomplete
vehicles. Such vehicles would not be required to meet the vocational
vehicle standards. Because sales volumes of Class 4 and 5 trucks are
relatively small, and because we expect these Class 4 and 5 and Class
2b and 3 trucks to generally use the same technologies and face roughly
the same technology challenge in meeting their standards targets, we do
not believe that this provision will dilute the stringency of the fleet
average standards.
    Any in-use testing of vehicles that are chassis-certified using the
sister vehicle provisions would involve 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 who finish incomplete
vehicles certified using the sister vehicle provisions would not be
subject to requirements under these regulations, 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 we are establishing in these rules.
    Finally, we are adopting a related special provision involving
chassis-certification aimed at simplifying compliance for manufacturers
of complete HD pickups and vans that also sell a relatively small
number of engines that are designed for other manufacturers' heavy-duty
vehicles--normally referred to as `loose' engines. Today these loose
engines must be engine-certified for criteria pollutants, even though
most of the vehicles that use the engines are chassis-certified. Our
new provision does not change this, but it does provide manufacturers
with an option to focus their energy on improving the GHG and fuel
consumption performance of their complete vehicle products (including,
most likely, significant engine improvements), rather than on
concurrently calibrating for both vehicle and engine test compliance.
    These loose engines would not be certified to engine-based GHG and
fuel consumption standards, but instead would be treated as though they
were additional sales of the manufacturer's complete pickup and van
products, on a one-for-one basis. The pickup/van vehicle so chosen must
be the vehicle with the highest ETW that uses the engine (as this
vehicle is likely to have the highest GHG emissions and fuel
consumption). However, if this vehicle is a credit-generator under the
HD pickup and van fleet averaging program, no credits would be
generated by these engine-as-vehicle contributors to the fleet average;
they would be treated as just achieving the target standard. If, on the
other hand, the vehicle is a credit-user, the appropriate number of
additional credits would be needed to offset the engine-as-vehicle
contributors. The purchaser of the engine would treat it as any other
certified engine, and would still need to meet applicable vocational
vehicle standards for the vehicles in which the engine is installed.
    Because it is our intent that this loose engine provision
simplifies compliance for HD pickup/van manufacturers who sell a
relatively small number of engines for other manufacturers'
applications, we are limiting its use to 10 percent of the total
engines (15,000 maximum) of the same design that a manufacturer
produces in each model year for U.S.-directed heavy-duty application--
including complete vehicles, incomplete vehicles, and the loose engines
themselves. We are further limiting both this provision and the above-
described provision for chassis certification of Class 4/5 vehicles to
spark-ignition (gasoline) engines, because we believe that the HD
diesel engine business is more focused on designing for and marketing
into a wide variety of vehicles products, instead of into the engine
manufacturer's own chassis-certified vehicle products with a small
loose engine business on the side, as is common for HD gasoline
engines. This dynamic is also reflected in the existing provision for
criteria pollutants allowing complete HD vehicles to use certified
diesel engines but not certified gasoline engines.
    Together these provisions provide a robust approach to regulating
these vehicles and engines. Although these certification options are
not as straightforward as the certification provisions for complete
Class 2b/3 pickups and vans, they are technically appropriate (for the
reasons explained above) and should accomplish more improvement in GHG
and fuel consumption performance than simply applying the vocational
vehicle and engine standards.
(2) 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 final 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 rulemaking. 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 rulemaking is not known. EPA will assess its compliance testing
and other activities associated with the program and may amend its fees
regulations in the future to include any justifiable new costs.
(4) Compliance Reports
(a) Pre-Model Year Report
    In the NPRM, EPA and NHTSA proposed that manufacturers must submit
early model year compliance reports demonstrating how their entire
fleets of heavy-duty pickup trucks and vans would comply with GHG
emissions and fuel consumption standards. The agencies understood that
early model year reports would contain estimates that may change over
the course of a model year and that compliance information manufactures
submit prior to the beginning of a new model year may not represent the
final compliance outcome. The agencies viewed the necessity for
requiring early model reports as a manufacturer's good faith projection
for demonstrating compliance with emission and fuel consumption
standards. The preamble language indicated that the compliance reports
would be submitted prior to the beginning of the model year and prior
to the certification of any test group. Preferably, a manufacturer
would submit its reports during its annual certification preview
meeting. Precertification preview meetings are typically held with a
manufacturer before the earliest date that the model year can begin
which is January 2nd of the calendar year prior to the model year.
Manufacturers voluntarily choose to participate in precertification
compliance meetings but meetings are not required by EPA and NHTSA
regulations. Manufacturers opt to participate in precertification
meetings because of the advantage it gives to exploring with the
agencies any possible compliance problems that may arise prior to
seeking approval for certificates of conformity. The NPRM preamble text
did not specify an exact date for manufacturers to submit early
compliance reports to the agency. NHTSA attempted to adopt requirements
in its regulatory text for manufactures to submit their early
compliance reports no later than the end of December two years prior to
the model year. NHTSA also proposed for manufacturers to provide
compliance information for the current model year and to the extent
possible two years into the future. NHTSA chose its submission deadline
and model years for reporting based upon the same dates required by EPA
in its CAFE provisions for light-duty pickups and vans beginning in
model year 2012.
    The NPRM included requirements for manufacturers to submit early
model year compliance reports separately to each agency based upon
limitations existing in the statutory authorities prescribed under EISA
and CAA and the long-standing precedent set in the LD CAFE programs for
receiving reports. The EPA report, called the pre-model year report,
and NHTSA report, called the pre-certification compliance report, were
proposed to include an estimate of the manufacturer's attribute-based
standards, along with a demonstration of compliance with the standards
based on projected model-level and fleet CO2 emissions and
fuel consumption results, and were to include an estimate of the
manufacturer's production volumes. The NPRM also included a proposal
for submitting a credit plan for manufacturers seeking to take
advantage of credit flexibilities and a credit deficit plan for
manufacturers planning to accrue deficits during the model years.
Additionally, NHTSA attempted to reduce the burden on manufacturers by
allowing them to submit copies of EPA's proposed pre-model year reports
or applications for certifications of conformity, as a substitute to
its own compliance report, so long as EPA's reports were submitted with
equivalent fuel consumption information. In either case, NHTSA reserved
the right to ask manufacturers to provide additional information if
necessary to verify its fuel consumption requirements under this
program. EPA and NHTSA also proposed to review the compliance reports
for technical viability and to conduct a certification preview
discussion with the manufacturer. It was further proposed that the EPA
Administrator would have to approve a manufacturer's pre-model year
report before it would consider issuing any certificate of compliance
for the manufacturer.
    Comments were received to the NPRM from EMA and TMA strongly
opposing providing separate reports to EPA and NHTSA and requested that
the agencies implement a single uniform reporting template that could
be submitted to both agencies simultaneously. DTNA requested that NHTSA
eliminate its pre-certification compliance report, arguing that report
was overly burdensome.
    For the final rules, the agencies have decided to require
manufacturers to submit a single report, hereafter referenced as the
pre-model year report, to satisfy both agencies requirements for
receiving compliance reports in advance of the model year. The agencies
considered the commenters' requests and determined that the benefit
gained by receiving separate or distinct compliance reports would not
outweigh the burden placed on manufacturers in reporting. Therefore,
the final rules establish a harmonized approach by which manufacturers
will submit a single report through the EPA database system as the
single point of entry for all information required for this national
program and both agencies will have access to the information. If by
model year 2012, the agencies are not prepared to receive information
through the EPA database system, manufacturers are expected to submit
written reports to the agencies. EPA and NHTSA have determined that
requiring manufacturers to submit a joint pre-model year report for
their combined fleet of heavy-duty pickup trucks containing both
emissions and equivalent fuel consumption information falls within each
agencies' statutory authority. The final rules require a manufacturer
to submit the joint pre-model year report as early as the date of the
manufacturer's annual certification preview meeting, or prior to the
manufacturer submitting its first application for a certificate for the
given model year. Consequently, a manufacturer choosing to comply in
model year 2014 could submit its pre-model year report during its
precertification meeting, which could occur before January 2, 2013.
Alternately, the manufacturer could provide its pre-model year report
any time prior to submitting its first application. In either case, a
manufacturer would not be able to certify any of its test groups until
the

EPA Administrator approves its pre-model year report. NHTSA will use
the pre-model year report as preliminary model year data.
    The agencies are adopting similar requirements for the pre-model
year reports as proposed. As mentioned, the agencies proposed that
reports would include an estimate of the manufacturer's attribute-based
standards, expected testing results and estimated production volumes.
The agencies agree that this information is essential for tracking
compliance of manufacturers and is therefore adopted for the final
rules. The final rules require manufacturers to identify any vehicle
exclusions and other flexibilities afforded for heavy-duty pickups and
vans. The summary of the required information for each pre-model year
report is as follows:
     A list of each unique vehicle configuration included in
the manufacturer's fleet describing the make and model designations,
attribute based-values (GVWR, GCWR, Curb Weight and drive
configurations) and standards.
     The emission and fuel consumption fleet average standard
derived from the unique vehicle configurations;
     The estimated vehicle configuration, test group and fleet
production volumes;
     The expected emissions and fuel consumption test group
results and fleet average performance;
     A statement declaring whether the manufacturer chooses to
comply early in MY 2013 for EPA and NHTSA. The manufacturers must
acknowledge that once selected, the decision cannot be reversed and the
manufacturer will continue to comply with the fuel consumption
standards for subsequent model years;
     A statement declaring whether the manufacturer will use
fixed or increasing standards; acknowledging that once selected, the
decision cannot be reversed and the manufacturer must continue to
comply with the same alternative for subsequent model years;
     A statement declaring whether the manufacturer chooses to
comply voluntarily with NHTSA's fuel consumption standards for model
years 2014 through 2015. The manufacturers must acknowledge that once
selected, the decision cannot be reversed and the manufacturer will
continue to comply with the fuel consumption standards for subsequent
model years;
     The list of Class 2b-3 cab-complete vehicles and the
method use to certify, as vocational vehicles and engines, or as
complete pickups and vans identifying the most similar complete
vehicles used to derive the target standards and performance test
results;
     The list of Class 2b-3 incomplete vehicles and the method
use to certify, as vocational vehicles and engines, or as complete
pickups and vans identifying the most similar complete vehicles used to
derive the target standards and performance test results;
     The list of Class 4 and 5 incomplete and complete vehicles
and the method use to certify, as vocational vehicles and engines, or
as complete pickups and vans identifying the most similar complete
vehicles used to derive the target standards and performance test
results;
     List of loose engines included in the heavy-duty pickup
and van category and the list of vehicles used to derive target
standards.
     Copy of any notices a vehicle manufacturer sends to the
engine manufacturer to notify the engine manufacturers that their
engines are subject to emissions and fuel consumption standards and
that it intends to use their engines in excluded vehicles; and
     A credit plan identifying the manufacturers estimated
credit balances, planned credit flexibilities (i.e., credit balances,
planned credit trading, innovative, advanced and early credits and
etc.) and if needed a credit deficit plan demonstrating how it plans to
resolve any credit deficits that might occur for a model year within a
period of up to three model years after that deficit has occurred.
(b) Final Reports
    The NPRM proposed for manufacturers participating in the ABT
program to provide two types of year end reports; end-of-the-year (EOY)
reports and final reports. The EOY reports for the ABT program were
required to be submitted by manufacturers no later than 90 days after
the calendar year and final report no later than 270 days after the
calendar year.\311\ Manufacturers not participating in the ABT program
were required to provide an EOY report within 45 days after the
calendar year but no final reports were required. The submission
deadline of the final ABT report was established to coincide with EPA's
existing criteria pollutant report for heavy-duty engines. The EOY
report is used by the agencies to review a manufacturer's preliminary
final estimates and to identify manufacturers that might have a credit
deficit for the given model year. Manufacturers with a credit surplus
at the end of each model year could submit a request to the agencies to
receive a waiver from providing EOY reports. As proposed, the remaining
manufacturers were required to submit reports to EPA and send copies of
those reports to NHTSA with equivalent fuel consumption values.
Manufacturers requesting to exempt vehicles in accordance with the
agencies' off-road vehicle exemption were required to a submit EOY
reports to the agencies identifying the vehicle applicable to each
report within 90 days after the model year ended.
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    \311\ Corresponding to the compliance model year
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    Comments in response to the NPRM did not oppose providing EOY
reports to the agencies but instead requested that they be allowed to
consolidate the various EOY reports into one single submission to the
agencies.
    Upon consideration of commenters' requests, the agencies agree that
only one consolidated EOY report should be submitted in place of the
separate reports proposed in the NPRM. The consolidated EOY report
should include the combination of all the required information that is
applicable to a manufacturer's fleet. The agencies also agree to allow
manufacturers to no longer provide separate EOY reports to each agency
independently but rather to submit the single report through the EPA
database system as the single point of entry for all information
required for this national program. The consolidated EOY report is
required to contain both GHG emissions and fuel consumption
information. EPA will provide access to the information for both
agencies. Likewise, manufacturers will be required to electronically
provide one single final report through the EPA database system. If by
model year 2012, the agencies are not prepared to receive information
through the EPA database system, manufacturers are expected to submit
written reports to the agencies. The required information for EOY and
final reports that manufacturers must submit is as follows: A finalized
list of each unique vehicle configuration included in the manufacturers
fleet describing the designations, attribute based-values (GVWR, GCWR,
Curb Weight and drive configurations) and standards.
     The final emission and fuel consumption fleet average
standard derived from the unique vehicle configurations;
     The final vehicle configuration, test group and fleet
production volumes;
     The final emissions and fuel consumption test group
results and fleet average performance;
     The final list of cab-complete vehicles and the method use
to certify, as vocational vehicles and engine, or as

complete pickups and vans identifying the most similar complete
vehicles used to derive the target standards and performance test
results;
     A final credit plan identifying the manufacturers
estimated credit balances, planned credit flexibilities (i.e., credit
balances, planned credit trading, innovative, advanced and early
credits, and etc.) and if needed a credit deficit plan demonstrating
how it plans to resolve any credit deficits that might occur for a
model year within a period of up to three model years after that
deficit has occurred;
     A plan describing the vehicles that were exempted such as
for off-road or small business purposes; and
     A plan describing any alternative fueled vehicles that
were produced for the model year identifying the approaches used to
determine compliance and the production volumes.

C. Heavy-Duty Engines

(i) Compliance Approach
    Section 203 of the CAA requires that all motor vehicles and engines
sold in the United States 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 comply 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 and NHTSA believe this compliance structure is also
valid for administering the final 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 engine characteristics that are normally
used to combine emissions families include similar combustion cycle,
aspiration methods, and aftertreatment systems. 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 continuing the use of this approach for the selection of the
worst-case engine (``parent rating'') for fuel consumption and GHG
emissions as well. As at proposal, 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. See 75 FR at 72264 for further information. 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. However, this higher fuel consumption rate is
misleading in the context of comparing engines within a single engine
family. This apparent 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 consistent with our current approach requiring manufacturers
to certify the worst case configuration.
    As explained at proposal, 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 finalizing 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 finalizing 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. 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 agencies received comments from engine and truck
manufacturers which indicated the useful life provisions applicable to
criteria pollutants seemed appropriate for GHG emissions. For that
reason, the agencies are retaining many of the same provisions for GHG
certification for family useful life provisions as developed for
criteria pollutants.
    EPA utilizes a 12-digit naming convention for all mobile-source
engine families (and test groups for light-duty 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, the code ``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
finalizing any major changes to this naming convention for this
rulemaking. There may be additional categories defined for the 5th
character to address heavy-duty vehicle families, 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 vehicle rule. During the
light-duty vehicle rulemaking, the conclusion was reached that no
significant deterioration would occur over the useful life. Therefore,
EPA is recommending that manufacturers use assigned DFs for
CO2. For this final action, we believe appropriate values
are zero (for additive DFs) and one (for multiplicative DFs). EPA will
continue to collect data regarding deterioration of CO2
emissions and may revisit these assigned values if necessary.
    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 EPA cannot rule
out the possibility that engine/aftertreatment wear will have a
negative impact on GHG emissions. To address useful life compliance for
MHD and HHD diesel engines certified to GHG standards, EPA therefore
believes that the criteria pollutant approach for developing DFs is
appropriate. Using CO2 as an example, many types of engine
deterioration 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. However, we expect engine manufacturers
to consider performance degradation in the design of engine and
aftertreatment systems given the market incentive to reduce fuel
consumption and related CO2 emissions. For these reasons,
EPA is not eliminating the DF from this program, but will allow for an
assigned DF of zero.
    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 provide
detailed maintenance instructions. 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-rating 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, it
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, EPA
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. For reasons stated previously regarding the useful
life provisions, EPA is retaining many of the same provisions for GHG
certification for family useful life provisions as developed for
criteria pollutants.
(b) Demonstrating Compliance with the 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.
    As proposed, 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 for GHGs. The FEL differs from the FCL in that it
includes an EPA-defined compliance margin; which has been defined at 3
percent for the final rule. Our proposal included a two percent margin
based on round-robin testing of the same engine at several
laboratories. Since that time, additional confidential data provided by
manufacturers has indicated that it may be more appropriate to use a
three percent margin to also account for production variability between
engines.\312\ Under this final action, the FEL will always be three
percent higher than the FCL.
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    \312\ See discussion in RIA <IP_ADDRESS>.
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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 rule, 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. As we
discussed at proposal, 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 finalizing 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 will 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 combination tractors will
use the ramped-modal cycle for GHG certification, and engines used in
vocational vehicles will use the Heavy-duty FTP cycle. In both cases,
results from the other test cycle will 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 proposed that manufacturers submit both data sets from
the transient test at the time of certification. This includes
providing both cold start and hot start transient heavy-duty FTP
emissions results, as well as the composite emissions at the time of
certification. The proposed rules also required that manufacturers
submit modal data from the ramped-modal cycle test. This was proposed
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.
    However several commenters were concerned that modal data was non-
discernable when batch sampling was used for certification testing.
Thus, an additional certification test (or tests) would need to be done
using either continuous analyzers or batch sampling at each mode; each
option raising the cost and complexity of certification testing. The
agencies agree that (at this time) this raises practical issues for
certification testing, however we also believe that manufacturers have
significant data from these modal points which could be used to satisfy
our model refinement goals.
    The agencies also recognize that even minor variations in test fuel
properties can have an impact on measured CO2 emissions.
Therefore, measured CO2 results are to be corrected using a
reference energy content, which is defined in the regulations. This
correction must be performed for each test and each batch of test fuel.
However, manufacturers may develop robust testing procedures that
reduce the variation in test fuel properties to within the level of
measurement uncertainty of the fuel properties themselves. If this is
the case, an annual review is still necessary to confirm the validity
of this constant value.
    As explained above in Section II, the agencies are finalizing 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 category. 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. 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
these final rules. Therefore, we are allowing manufacturers to use EPA-
assigned DFs for CO2. However, we also understand that
CO2 is traditionally measured as

part of normal engine dynamometer testing. Therefore, we are requiring
that manufacturers include CO2 data over their criteria
pollutant durability demonstrations (if available), which will aid the
agency in developing more accurate assigned DFs. This action is being
taken in the context of engine manufacturers' concerns regarding the
impact of deterioration of emissions components relative to the GHG
standards. Engine manufacturers commented that there would be no
deterioration of components used to reduce GHG emissions in Phase 1. As
part of the Clean Air Act responsibility to demonstrate compliance
throughout the useful life, manufacturer will need to provide data
already collected during traditional criteria pollutant testing for
full useful life performance.
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 duration of 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 requiring the
use of infrequent regeneration adjustment factors for CO2 or
fuel efficiency in this program. This is consistent with comments
received from engine manufacturers.
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, which 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
finalizing 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). Although 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. As noted in section II
above, 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 requiring that CH4 and N2O be reported
at the time of certification, however we will allow manufacturers to
submit 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 requiring 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 discussed above, in cases where
N2O emissions directly tradeoff with CO2
emissions, EPA is allowing manufacturers to exploit this relationship
to produce engines with the lowest overall GHG emissions. Direct
measurement of N2O emissions is required in the case of
engines utilizing this temporary credit program.
    Since catalytic activity generally changes with age and service
accumulation, it is not unreasonable to expect changes in
N2O and CH4 emissions over the useful life of the
engine. We also believe that low-hour test results coupled with
deterioration factors provides an adequate representation of end-of-
life emission levels for these pollutants. However, the requirement to
measure N2O and CH4 during testing is relatively
new and we do not expect that manufacturers have consistent durability
data to formulate deterioration factors for today's action. We also do
not believe it is appropriate to require all new durability testing to
satisfy this requirement, as this would result in a nontrivial burden
to engine manufacturers. Instead we will be assigning deterioration
factors for N2O and CH4 for this action. If the
use of assigned deterioration factors jeopardizes compliance with the
emission standards, we will also allow manufacturers to propose unique
testing-based deterioration factors for these pollutants. In response
to comments received from engine manufacturers regarding the timing
needed to generate deterioration factors the agencies are taking this
approach.
    Concerns had also been raised by engine manufacturers regarding
measurement techniques for quantifying N2O emissions. In an
effort to expand testing options, we are adding an allowance to use
laser infrared analyzers for N2O measurement in 40 CFR part
1065.275. This is to reflect the recent development of this technology
for N2O measurement. We would also like to serve notice that
in an upcoming rulemaking, we will be tightening the interference
tolerance (both positive and negative) for engines and vehicles that
are required to certify to an N2O standard. This will
consist of an interference limit based on interference as a percentage
of the flow weighted mean concentration of N2O expected at
the standard. For example we may set the interference limit at 10 percent of the flow weighted mean concentration of
N2O expected at the standard and strongly recommend a lower
interference that is within 5 percent.
(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 category 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. We remain
convinced that this list is adequate for addressing GHG emissions as
well, based on comments received from the proposed rules. 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
percent 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 is not expected to present unique challenges. Therefore, we
are not finalizing any changes to the provisions for the specification
of emission-related maintenance as outlined in 40 CFR part 86.
(2) 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 will 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.
Finally, if an engine family is uniquely certified for use in hybrid
powertrain applications, a compliance statement indicating this will
need to be included on the emission control label.
    In response to comments from engine and truck manufacturers that
tractors should be allowed to obtain engines certified for vocational
use and likewise a limited number of engines certified for tractor use
should be available for the appropriate vocational applications, the
agencies are allowing limited use of engines certified in other
categories. To address compliance needs and to discourage abuse of the
provisions, proper labeling of the engines is essential.
(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 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, possibly involving a
product recall, 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 they are not
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 proposed and are adopting that
manufacturers be required to submit CO2 data from in-situ
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). For the purposes of calculating the g/ton-mile metric,
we prefer that manufacturers use the measured vehicle weight. However
it has been brought to our attention that this may not always be
available, in which case an estimated vehicle weight can be used along
with a written justification for the basis of the estimation. For
engine-based (dynamometer) in-use testing, compliance with
CO2 emission standards will be judged off of the FCL of the
engine family.
(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 will 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
rulemaking. 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 program is not
known. EPA will assess its compliance testing and other activities
associated with the rules and may amend its fees regulations in the
future to include any justifiable new costs.
(c) Onboard Diagnostics
(a) Onboard Diagnostics
    Beginning with the 2010 model year, manufacturers have been phasing
in on-board diagnostic (OBD) systems on heavy-duty engines pursuant to
the heavy-duty OBD rulemaking finalized by the EPA in 2009.\313\ 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 2012-2016
MY vehicle rulemaking, we believe that monitoring of these components
and systems for criteria pollutant emissions will have an equally
beneficial effect on CO2 emissions.\314\ Therefore, we have
not finalized any additional unique onboard diagnostic provisions for
heavy-duty GHG emissions. In the NPRM, EPA did

not propose new or different diagnostic requirements from those
finalized in the 2009 heavy-duty OBD rule.
---------------------------------------------------------------------------

    \313\ U.S. EPA, ``Control of Air Pollution from New Motor
Vehicles and New Motor Vehicles Engines; Final Rule Regulations
Requiring Onboard Diagnostic Systems on 2010 and Later Heavy-Duty
Engines Used in Highway Applications Over 14,000 Pounds; Revisions
to Onboard Diagnostic Requirements for Diesel Highway Heavy-Duty
Vehicles Under 14,000 Pounds,'' published February 24, 2009.
Available here: http://www.epa.gov/otaq/regs/im/obd/regtech/hd-obd-frm-02-24-09-notice-74-fr-8310.pdf.
    \314\ See the Light-Duty 2012-2016 Vehicle Rule, Note 5, above.
---------------------------------------------------------------------------

    The agencies received comments from engine manufacturers, hybrid
system manufacturers, and related trade groups which broached concerns
regarding the feasibility of applying on-board diagnostics to hybrid
applications starting in 2013. The commenters stated that engine
manufacturers would need several years to adapt their engine OBD
systems to hybrids, and therefore requested a delay of OBD requirements
for hybrid applications until 2020 with a phase-in of enforcement
liability starting that same year. Details, which the agencies believe
have merit, are set out below. In response, EPA is taking an approach
that is consistent with certain provisions of the existing final action
for heavy-duty OBD, finalized in 2009. To that end, manufacturers who
certify hybrid systems will continue to have the responsibility of
implementing compliant diagnostic systems, however, we are extending
the OBD phase-in for engines with hybrid systems to allow time for
manufacturers to be able to address communication protocol development
concerns (e.g. SAE J1939, communication with diagnostic scantools),
component development concerns (e.g. hardware and software), and to
address the availability of heavy-duty OBD compliant engines with
sufficient lead-time for additional hybrid diagnostic system
development given resource constraints as engine manufacturers are
focused on meeting the 2013 requirements for conventional products at
this time.
    Since publication of the NPRM, the EPA has undertaken extensive
outreach to hybrid manufacturers, engine manufacturers, and related
industry groups to further understand the technical issues involved
with the implementation of full OBD on engine-hybrid systems.\315\
Hybrid manufacturers have indicated that the interaction between hybrid
systems and OBD compliant engines is not well understood at this time,
for example, if the system shuts down the vehicle at idle (as is
common), the OBD idle diagnostics cannot run. In addition, there are
many different hybrid systems being developed which make much of this
technology both immature and low volume, and engine manufacturers are
concerned that this will result in high costs due to frequent design
changes that could occur as this technology develops and have asked for
flexibility for unique hybrid applications. Consistent with the goal to
incentivize the development of hybrid designs (systems designed to
capture wasted energy and reduce fuel consumption) the EPA is allowing
hybrid manufacturers time to develop their systems while simultaneously
developing the capability to meet HD OBD requirements.
---------------------------------------------------------------------------

    \315\ See EPA Docket EPA-HQ-OAR-2010-0162 for memos describing
meetings held as a part of this outreach.
---------------------------------------------------------------------------

    Communication protocol development is an integral part of
developing hybrid OBD capability for the heavy-duty industry which is
not vertically integrated. There are different protocols required to be
used for OBD communication in a vehicle depending on the type of engine
(gasoline or diesel). These protocols are developed in part to
standardize the transmission of electronic signals and control
information among vehicle components. The J1939 communication protocol
is developed by committee through SAE and is required for use with
diesel engines. J1939 defines communications messages, diagnostic
messages for communications between a module and diagnostic scantool,
and fault codes. Messages sent through a J1939 network contain a series
of information (e.g. an identifier, message priority, data, etc.) and
these parameters must be agreed upon through the SAE committee and
tailored to work for all manufacturers. The development of this
communication protocol includes developing criteria for the messages,
and determining a single set of fault codes that can work for all
manufacturers and all hybrid system configurations; this is expected to
take a substantial amount of time and collaboration. OBD cannot exist
without fault codes to report, therefore development of this protocol
is critical. Hybrid manufacturers have stated that until such time as a
`plug and play scheme' is available, hybrid volumes will not be able to
increase significantly. At this time, there are only a few such
messages that have been developed for use in hybrid systems, and there
is much additional development that needs to take place. The type of
messages needed must first be identified once 2013 HD OBD compliant
engines are available for use in HD hybrid OBD system development.
After needed messages are identified, the content of each message must
be developed and agreed upon through a ballot process. Manufacturers
have stated that this will be an iterative process and will likely take
at least two years to develop the protocol for use with different
variations of hybrid systems and architectures, different types of
energy storage systems, and for systems used in the wide variety of
applications in the heavy-duty market, and we agree with this
assessment. While a level of communication exists today between engines
and transmissions for this industry, the level of control and impact on
engine system operation becomes much more significant once hybrid
technology is introduced. The purpose of the hybrid energy system is to
supplement overall vehicle power demands. As such, the methods used for
integrating the energy from the hybrid system into overall vehicle
operation vary from allowing additional internal combustion engine
lower power operation to potentially decreasing the amount of engine
``on'' time. This range of performance impacts will serve to reduce GHG
emissions by reducing demands on the engine. Conventional transmission
systems and other powertrain components do not exercise the level of
control the hybrid will need to exercise to effectively reduce GHG
emissions and improve fuel consumption performance for internal
combustion engines; therefore, hybrid OBD systems can reasonably be
expected to be more complicated as well.
    Component development concerns raised by hybrid manufacturers
include both changes that may be required to software and/or hardware
systems on both existing hybrid products and on hybrid systems
currently under development. Software systems in existing products have
been developed that provide proprietary diagnostic capability (as no
standardized system such as J1939 had been developed for these
systems), however, these software systems are not OBD compliant. These
products will likely require entirely new software systems developed
for them which may result in hardware changes as well. Manufacturers
have stated that a complete software system can take up to 2 years to
develop and validate. Hardware may also need to be changed to
accommodate OBD on hybrid systems. In particular, hardware changes
would affect current production systems which may not have controllers
that can support full OBD. The low volume sales and high cost of a
controller program (which can reach into the millions of dollars) means
that most companies cannot justify the cost of a hardware change for
hybrids alone, rather, existing hybrid systems will have to wait until
such a hardware upgrade is planned for other reasons. In addition, new
hardware programs, such as developing a new Electronic Control Unit,
can take 3-4 years to complete.

While it is possible for some of this work to be done concurrently, how
much can be done this way is dependent on the configuration of each
individual system. Finally, manufacturers may have contractual
agreements with hardware and software suppliers that will have to be
reconfigured to address a complete OBD program.
    Hybrid manufacturers have stated that they will be unable to
produce hybrid systems that will be OBD compliant in 2013. Given the
concerns discussed above and the general lack of availability of OBD
compliant engines until the completion of the HD OBD phase-in, to
require manufacturers of systems that depend on the availability of
those OBD complaint engines to then be able to immediately implement
additional requirements may be impractical or infeasible in many
instances. Given the phase-in of HD OBD requirements that already
exists however, we do not believe a delay to 2019 or 2020 is warranted.
While not all of the engines that would potentially have hybrid systems
incorporated into their design are available in their final OBD
configuration at the time of this action, it is clear that some engine
systems will be available. Additionally, there is an expectation that
engine manufacturers, their suppliers and customers will have to
continue to work cooperatively to deliver products for the market. This
cooperation must include a level of concurrent engineering prior to
products being brought to market. At this time we believe a delay to
2016 for the phase-in of OBD for heavy-duty engines equipped with
hybrid systems should provide the requisite lead time from the date of
this action to the date of implementation for development of components
and protocols necessary for successful integration of complete OBD
systems for engines equipped with hybrid systems.
    Manufacturers will be required to implement feasible controls for
these hybrid systems that do not adversely impact emissions performance
in 2013 and by 2016-17, all systems must be fully compliant with OBD
requirements. The phase in period takes into account that current
production systems are likely to be smaller in terms of sales volumes
than newly developed systems, and may require more hardware and
software development as some of these systems have been in production
for nearly a decade and have developed a proprietary system diagnostic
capability that does not meet OBD requirements. Therefore, this
extended phase-in provides them an additional year of time to comply
with the heavy-duty OBD regulations. Hybrid systems put into production
after January 1, 2013 will be required to meet the 2009 heavy-duty OBD
requirements in 2016 consistent with the next phase-in date for heavy-
duty OBD, while those hybrid systems released prior to January 1, 2013
have until 2017 to be compliant with these OBD requirements.
    If a manufacturer certifies an engine-hybrid system with CARB OBD
in California prior to the required phase-in date (2016 or 2017), and
its diagnostics meet or exceed the requirements for full 2013 OBD, the
manufacturer must either use the CARB certified package for Federal
release or phase in the package and certify it with full EPA OBD.
    In the interim, engine system diagnostics must show that they meet
or exceed CARB's Engine Manufacturer Diagnostic Systems Requirements
(EMD) including system monitoring requirements for NOX
aftertreatment, fuel systems, exhaust gas recirculation, particulate
matter traps, and emission-related electronic components.\316\ Specific
EMD requirements will be considered met if they are redundant due to
the installed engine's fully functioning OBD content. Most
manufacturers have already certified their engines with EMD for the
2011 model year, and full OBD as required in 2013 exceeds EMD
requirements, therefore no new cost burden is expected as a result of
this provision. In addition, new engines may be introduced in 2013 for
hybrid-only use and, in lieu of meeting full OBD, meeting EMD would
result in cost savings because of the flexibility in scan-tool
reporting and diagnostic content.
---------------------------------------------------------------------------

    \316\ California Air Resources Board, Final Regulation Order for
EMD, Section 1971 of Title 13, California Code of Regulations,
effective December 30, 2004. Available here; http://www.arb.ca.gov/regact/emd2004/fro.pdf.
---------------------------------------------------------------------------

    In addition, the engine-hybrid system must maintain existing OBD
capability for engines where the same or equivalent engine (e.g.
displacement) has been OBD certified. An equivalent engine is one
produced by the same engine manufacturer with the same fundamental
design, but that may have no more than minor hardware or calibration
differences, such as slightly different displacement, rated power, or
fuel system. Though the OBD capability must be maintained, it does not
have to meet detection thresholds and in-use performance frequency
requirements; for example, a manufacturer may modify detection
thresholds to prevent false detection.
    As stated earlier, existing hybrid systems sold today have
proprietary diagnostic capability that is non-OBD compliant, but
nonetheless will notify the driver of potential problems with the
system. Hybrid manufacturers must also continue to maintain this
existing diagnostic capability to ensure proper function consistent
with the performance for which the hybrid system is certified as well
as, safe operation of the hybrid system.
    Finally, during the interim part of the phase-in, manufacturers
that are not fully-OBD compliant must also submit an annual pre-
compliance report to the EPA for model years 2013 and later. The engine
manufacturers must submit this report with their engine certification
information. Hybrid manufacturers that are not certifying the engine-
hybrid systems must also submit an annual pre-compliance report to the
EPA. The report must include a description of the engine-hybrid system
being certified and related product plans, information as to activities
undertaken and progress made by the manufacturer in achieving full OBD
certification including monitoring, diagnostics, and standardization;
and deviations from an originally certified full-OBD package with
engineering justification.
(d) Applicability of Current High Altitude Provisions to Greenhouse
Gases
    EPA is requiring that engines covered by this program 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 will 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 to 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 result in the vehicle manufacturer being
in non-compliance.
(f) Alternate CO2 Emission and Fuel Consumption Standards
    Under the final rules, engine manufacturers have the option of
certifying to alternate CO2 emission and fuel consumption
standards for model years 2014 through 2016. These alternate standards
are defined as a certain percentage below a baseline value established
from their corresponding 2011 model-year products. For instance, the
alternate emission standard for light and medium heavy duty FTP-
certified (vocational) engines is equal to 0.975 times the baseline
value. If a manufacturer elects to participate in this program it must
indicate this on its 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. These 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.
(4) Compliance Reports
(a) Early Model Year Data
    NHTSA's regulatory text in the NPRM included specifications for
manufacturers to submit pre-certification compliance reports for heavy-
duty engines. The pre-certification reports included requirements for
manufacturers to submit information to identify the types of engines,
expected test results, production volumes and credits. The reporting
requirements were general in nature despite there being an existing
emissions program for heavy-duty engines. The existing ABT program for
NOX and PM emissions for heavy-duty engines has existed
since 2001 (see 66 FR 5002 signed on January 18, 2001) but does not
require reporting early model year compliance information. The agencies
sought comments on the report provisions in the NPRM but commenters
failed to offer recommendations on what content should be required. As
a result, the agencies have decided to eliminate the pre-certification
report because engine manufacturers have no experience in providing GHG
information and the proposed information may not be available until
subsequent model years. For the next phase of this GHG program, the
agencies may adopt a pre-model year report for engines.
    As an alternative to receiving early compliance model year
information in the precertification reports, the agencies have decided
to use manufacturer's application for certificates of conformity to
obtain early model estimates. Currently, the applications for
certificates are not required to include the fuel consumption
information required by NHTSA. Therefore, the agencies are adopting
provisions in the final rules for manufacturers to provide emission and
equivalent fuel consumption estimates in the manufacturer's
applications for certification. The agencies will treat information
submitted in the applications as a manufacturer's demonstration of
providing early compliance information, similar to the pre-model year
report submitted for heavy-duty pick-up trucks and vans. The final
rules establish a harmonized approach by which manufacturers will
submit applications through the EPA Verify database system as the
single point of entry for all information required for this national
program and both agencies will have access to the information. If by
model year 2012, the agencies are not prepared to receive information
through the EPA Verify database system, manufacturers are expected to
submit written applications to the agencies. This approach should
streamline this process and reduce industry burden and provide
sufficient information for the agencies to carry out their early
compliance activities.
(b) Final Reports
    For engines, the agencies proposed that manufacturers would submit
EOY reports and final reports. An EOY report for manufacturers using
the ABT program was required to be submitted no later than 90 days
after the calendar year and final report no later than 270 days after
the calendar year.\317\ Manufacturers not participating in the ABT
program were required to provide an EOY report within 45 days after the
calendar year but no final reports were required. The final ABT report
due date was established coinciding with EPA's existing criteria
pollutant report for heavy-duty engines complying with NOX
and PM standards. Similar to that program, the proposed EOY and final
reports required receiving engine type designation, engine family and
credit plans for engine manufacturers.
---------------------------------------------------------------------------

    \317\ Corresponding to the compliance model year.
---------------------------------------------------------------------------

    There were no comments received on the final reports for engines.
For the final rules, the agencies will retain the provisions as
proposed for the EOY and final reports. However, the agencies will
consolidate the reporting as done for other vehicle categories and will
require emissions and equivalent fuel consumption information to be
submitted to EPA. The final rules establish a harmonized approach by
which manufacturers will submit applications to EPA as the single point
of entry for all information required for this national program and
both agencies will have access to the appropriate information. If by
model year 2012, the agencies are not prepared to receive information
through a database system, manufacturers are expected to submit written
applications to the agencies. The agencies are also combining the EOY
reports for manufacturers not using ABT to provide a product volume
report due 90 days after the end of the model year and the ABT report
required 90 days after the model year. A summary of the required
information in the final rules for EOY and final reports is as follows:
     Engine family designation and averaging set.
     Engine emissions and fuel consumption standards including
any alternative standards used.
     Engine family FCLs.
     Final production volumes.
     Certified test cycles.
     Useful life values for engine families.
     A credit plan identifying the manufacturers actual credit
balances, credit flexibilities, credit trades and a credit deficit plan
if needed demonstrating how it plans to resolve

any credit deficits that might occur for a model year within a period
of up to three model years after that deficit has occurred.
(c) Additional Required Information
    Throughout the model year, manufacturers may be required to submit
various reports to the agencies to comply with various aspects of the
program. These reports have differing criteria for submission and
approval.
    Table V-1 below provides a summary of the types of submission,
required submission dates and the EPA and NHTSA regulations that apply
for engines and engine manufacturers.
    The agencies will review and grant any appropriate requests
considering the timeliness of the submissions and the completeness of
the requests.

                       Table V-1--Summary of Required Information for HD Engine Compliance
----------------------------------------------------------------------------------------------------------------
                                                                                NHTSA
            Submission                    Applies to        Required submissions  EPA regulation    regulation
                                                                    date             reference       reference
----------------------------------------------------------------------------------------------------------------
Small business exemptions.........  Engine manufacturers   Before introducing               Sec.    Sec.   535.8
                                     meeting the Small      any excluded vehicle        1036.150
                                     Business               into U.S. for
                                     Administration (SBA)   commerce.
                                     size criteria of a
                                     small business as
                                     described in 13 CFR
                                     121.201.
Incentives for early introduction.  The provisions apply   EPA must be notified             Sec.    Sec.   535.8
                                     with respect to        before the                  1036.150
                                     tractors and           manufacturer submits
                                     vocational vehicles    it applications for
                                     produced in model      certificates of
                                     years before 2014.     conformity.
Voluntary compliance for NHTSA      Engine manufacturers   NHSAT must be                      NA    Sec.   535.8
 standards.                          seeking early          notified before the
                                     compliance in model    manufacturer submits
                                     years 2014 to 2016.    it applications for
                                                            certificates of
                                                            conformity.
Model year 2014 N2O standards.....  Manufacturers that     EPA must be notified             Sec.              NA
                                     choose to show         before the                  1036.150
                                     compliance with the    manufacturer submits
                                     MY 2014 N2O            it applications for
                                     standards requesting   certificates of
                                     to use an              conformity.
                                     engineering analysis.
Exemption from EOY reports........  Manufacturers with     90-days after the                Sec.    Sec.   535.8
                                     surplus credits at     calendar year ends.         1036.730
                                     the end of the model
                                     year.
Alternative engine standards......  Engine manufacturers   EPA and NHTSA must be            Sec.    Sec.   535.8
                                     not able to comply     notified before the         1036.150
                                     with 1036.104 and      manufacturer submits
                                     wanting to use the     it applications for
                                     alternative engine     certificates of
                                     standard.              conformity.
Alternate phase-in................  Engine manufacturers   EPA and NHTSA must be            Sec.    Sec.   535.8
                                     want to comply with    notified before the         1036.150
                                     alternate phase in     manufacturer submits
                                     standards.             it applications for
                                                            certificates of
                                                            conformity.
----------------------------------------------------------------------------------------------------------------

D. Class 7 and 8 Combination Tractors

(1) 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 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 will 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 will also be required to warrant their products
against emission control system defects, and demonstrate that a service