CFR 393.82. The requirements apply to speedometers and states as
follows:

    Each bus, truck, and truck-tractor must be equipped with a
speedometer indicating vehicle speed in miles per hour and/or
kilometers per hour. The speedometer must be accurate to within plus
or minus 8 km/hr (5 mph) at a speed of 80 km/hr (50 mph).

    To facilitate adjustments for component changes affecting vehicle
speed, manufacturers should provide a fleet/owner with the means to do
so unless the adjustments would affect the VSL setting or operation.
    DTNA and ATA additionally requested that the agencies ensure that
any VSL provisions adopted under the GHG emissions and fuel efficiency
rules align with existing NHTSA standards. The agencies agree and note
that there are no existing standards for a VSL outside of this current
rulemaking activity. However, NHTSA has announced its intent to publish
a proposal in 2012 for a VSL.\94\ While both agencies have taken steps
to avoid potential conflicts between the rulemaking being finalized
today for fuel consumption and GHG emissions and the anticipated safety
rulemaking, different conclusions may be reached in a safety-based
rulemaking on VSLs, particularly in the approach to specifying soft top
parameters and VSL expiration.
---------------------------------------------------------------------------

    \94\ 76 FR 78.
---------------------------------------------------------------------------

(h) Defined Vehicle Configurations in the GEM
    As discussed above, the agencies are adopting methodologies that
manufacturers will use to quantify the values input into the GEM for
these factors affecting vehicle efficiency: Coefficient of Drag, Tire
Rolling Resistance Coefficient, Weight Reduction, Vehicle Speed
Limiter, and Extended Idle Reduction Technology. The other aspects of
the vehicle configuration are fixed within the model and are not varied
for the purpose of compliance. The defined inputs include the tractor-
trailer combination curb weight, payload, engine characteristics, and
drivetrain for each vehicle type, and others.
(i) Vehicle Drive Cycles
    The GEM simulation model uses various inputs to characterize a
vehicle's configuration (such as weight, aerodynamics, and rolling
resistance) and predicts how the vehicle would behave on the road when
it follows a driving cycle (vehicle speed versus time). As noted by the
2010 NAS Report,\95\ the choice of a drive cycle used in compliance
testing has significant consequences on the technology that will be
employed to achieve a standard as well as the ability of the technology
to achieve real world reductions in emissions and improvements in fuel
consumption. Manufacturers naturally will design vehicles to ensure
they satisfy regulatory standards. An ill-suited drive cycle for a
regulatory category could encourage GHG emissions and fuel consumption
technologies which satisfy the test but do not achieve the same
benefits in use. For example, requiring all trucks to use a constant
speed highway drive cycle will drive significant aerodynamic
improvements. However, in the real world a combination tractor used for
local delivery may spend little time on the highway, reducing the
benefits achieved by this technology. In addition, the extra weight of
the aerodynamic fairings will actually penalize the GHG and fuel
consumption performance in urban driving and may reduce the freight
carrying capability. The unique nature of the kinds of CO2
emissions control and fuel consumption technology means that the same
technology can be of benefit during some operation but cause a reduced
benefit under other operation.\96\ To maximize the GHG emissions and
fuel consumption benefits and avoid unintended reductions in benefits,
the drive cycle should focus on promoting technology that produces
benefits during the primary operation modes of the application.
Consequently, drive cycles used in GHG emissions and fuel consumption
compliance testing should reasonably represent the primary actual use,
notwithstanding that every vehicle has a different drive cycle in-use.
---------------------------------------------------------------------------

    \95\ See 2010 NAS Report, Note 21, Chapters 4 and 8.
    \96\ This situation does not typically occur for heavy-duty
emission control technology designed to control criteria pollutants
such as PM and NOX.
---------------------------------------------------------------------------

    The agencies proposed a modified version of the California ARB
Heavy Heavy-duty Truck 5 Mode Cycle \97\, using the basis of three of
the cycles which best mirror Class 7 and 8 combination tractor driving
patterns, based on information from EPA's MOVES model.\98\ The key
advantage of the California ARB 5 mode cycle is that it provides the
flexibility to use several different modes and weight the modes to fit
specific vehicle application usage patterns. For the proposal, EPA
analyzed the five cycles and found that some modifications to the
cycles were required to allow sufficient flexibility in weightings. The
agencies proposed the use of the Transient mode, as defined by
California ARB, because it broadly covers urban driving. The agencies
also proposed altered versions of the High Speed Cruise and Low Speed
Cruise modes which reflected only constant speed cycles at 65 mph and
55 mph respectively. In the NPRM, the agencies proposed to use three
cycles which were the ARB transient cycle, a 55 mph steady state
cruise, and a 65 mph steady state cruise.
---------------------------------------------------------------------------

    \97\ California Air Resources Board. Heavy Heavy-duty Diesel
Truck chassis dynamometer schedule, Transient Mode. Last accessed on
August 2, 2010 at http://www.dieselnet.com/standards/cycles/hhddt.html.
    \98\ EPA's MOVES (Motor Vehicle Emission Simulator). See http://www.epa.gov/otaq/models/moves/index.htm for additional information.
---------------------------------------------------------------------------

    The agencies received comment from NACAA recommending an increase
in the high speed cruise cycle speed from the proposed value of 65 mph
to 75 mph because trucks travel at higher speeds. The agencies analyzed
the urban and rural interstate truck speed limits in each state to
determine the national average truck speed limit. State interstate
speed limits for trucks vary between 55 and 75 mph, depending on the
state.\99\ Based on this information, the national median truck speed
limit is

65 mph. The agencies also analyzed the national average truck speed
limit weighted by VMT for each state based on VMT data by state from
the Federal Highway Administration as described in RIA Section 3.4.2.
Based on this information, the national average VMT-weighted truck
speed limit is 63 mph. The agencies continue to believe that the
appropriate high speed cruise speed should be set at the national
average truck speed limit to appropriately balance the evaluation of
technologies such as aerodynamics, but not overstate the benefits of
these technologies. Therefore, the agencies are adopting as proposed a
speed of 65 mph for the high speed cruise cycle.
---------------------------------------------------------------------------

    \99\ Governors Highway Safety Association. Speed Limit Laws May
2011. Last viewed on May 9, 2011 at http://www.ghsa.org/html/stateinfo/laws/speedlimit_laws.html.
---------------------------------------------------------------------------

    The agencies also received comments from Allison which disagreed
with proposed drive cycles for combination tractors because the cycles
did not account for external factors such as grades, wind, traffic
condition, etc. Allison also believes that the acceleration rates are
too low. The agencies recognize that the proposed drive cycles do not
incorporate the external factors described by Allison. Parallel to the
approach used to evaluate light-duty vehicles, the drive cycles do not
incorporate either grade or wind which can be difficult to simulate in
chassis dynamometer cells. In the final rules, the agencies are
defining an approach that manufacturers may take to evaluate their
aerodynamic packages in a wind-averaged condition and use a modified Cd
value in GEM.\100\ The agencies are also adopting provisions for the
innovative technology demonstration that allows for the use of on-road
testing which includes grades for technologies whose benefits are
reflected with grade. Lastly, the agencies' final drive cycles for
highway operation contain a constant speed, as proposed. The
acceleration and deceleration rates are only used to bring the vehicle
to the cruising speed and the CO2 emissions and fuel
consumption from these portions of the drive cycle are not included in
the composite emissions and fuel consumption results. The agencies did
not include the speed dithering, which is representative of actual
driving and traffic conditions, in the proposed constant speed portion
of the cycles because the dithering does not provide any additional
distinction between technologies but only added complexity to the
cycle. The agencies believe this approach is still appropriate for the
final action.
---------------------------------------------------------------------------

    \100\ See Section IV.B.3.b below.
---------------------------------------------------------------------------

    Allison referred the agencies to the Oak Ridge National Laboratory
and SmartWay program to review the amount of time long-haul vehicles
spend on the highway. They believe the steady state highway speeds are
overestimated. Data provided by Allison indicates that day cabs spend
only 14 percent of miles traveling at speeds greater than 60 mph. NHTSA
and EPA recognize that there is a variation in the amount of miles day
cabs travel under different operations. As described above, the
agencies are adopting an approach where tractors which operate like
vocational vehicles may be regulated as such in the HD program. Thus,
these day cabs will have a drive cycle weighting representative of
vocational vehicles with more weighting on the transient operation and
less on the highway speed operation.
    For proposal, EPA and NHTSA relied on the EPA MOVES analysis of
Federal Highway Administration data to develop the mode weightings to
characterize typical operations of heavy-duty trucks, per Table II-10
below.\101\ A detailed discussion of drive cycles is included in RIA
Chapter 3.\102\ The agencies are adopting the proposed drive cycle
weightings for combination tractors.
---------------------------------------------------------------------------

    \101\ The Environmental Protection Agency. Draft MOVES2009
Highway Vehicle Population and Activity Data. EPA-420-P-09-001,
August 2009 http://www.epa.gov/otaq/models/moves/techdocs/420p09001.pdf.
    \102\ In the light-duty vehicle rule, EPA and NHTSA based
compliance with tailpipe standards on use of the FTP and HFET, and
declined to use alternative tests. See 75 FR 25407. NHTSA is
mandated to use the FTP and HFET tests for CAFE standards, and all
relevant data was obtained by FTP and HFET testing in any case. Id.
Neither of these constraints exists for Class 7-8 tractors. The
little data which exist on current performance are principally
measured by the ARB Heavy Heavy-duty Truck 5 Mode Cycle testing, and
NHTSA is not mandated to use the FTP to establish heavy-duty fuel
economy standards. See 49 U.S.C. 32902(k)(2) authorizing NHTSA,
among other things, to adopt and implement appropriate ``test
methods, measurement metrics, * * * and compliance protocols''.

                Table II-10--Drive Cycle Mode Weightings
------------------------------------------------------------------------
                                                   55 mph       65 mph
                                    Transient      cruise       cruise
------------------------------------------------------------------------
Day Cabs.........................          19%          17%          64%
Sleeper Cabs.....................           5%           9%          86%
------------------------------------------------------------------------

(ii) Standardized Trailers
    As proposed, NHTSA and EPA are adopting provisions so that the
tractor performance in the GEM is judged assuming the tractor is
pulling a standardized trailer. The agencies did not receive any
adverse comments related to this approach. The agencies believe that an
assessment of the tractor fuel consumption and CO2 emissions
should be conducted using a tractor-trailer combination. We believe
this approach best reflects the impact of the overall weight of the
tractor-trailer and the aerodynamic technologies in actual use, where
tractors are designed and used with a trailer. The GEM will continue to
use a predefined typical trailer in assessing overall performance. The
high roof sleeper cabs are paired with a standard box trailer; the mid
roof tractors are paired with a tanker trailer; and the low roof
tractors are paired with a flat bed trailer.
(iii) Empty Weight and Payload
    The total weight of the tractor-trailer combination is the sum of
the tractor curb weight, the trailer curb weight, and the payload. The
total weight of a vehicle is important because it in part determines
the impact of technologies, such as rolling resistance, on GHG
emissions and fuel consumption. In this final action, the agencies are
specifying each of these aspects of the vehicle, as proposed.
    In use, trucks operate at different weights at different times
during their operations. The greatest freight transport efficiency (the
amount of fuel required to move a ton of payload) would be achieved by
operating trucks at the maximum load for which they are designed all of
the time. However, logistics such as delivery demands which require
that trucks travel without full loads, the density of payload, and the
availability of full loads of freight limit the ability of trucks to
operate at their highest efficiency all the time. M.J. Bradley analyzed
the Truck Inventory and Use Survey and found that

approximately 9 percent of combination tractor miles travelled empty,
61 percent are ``cubed-out'' (the trailer is full before the weight
limit is reached), and 30 percent are ``weighed out'' (operating weight
equal 80,000 pounds which is the gross vehicle weight limit on the
Federal Interstate Highway System or greater than 80,000 pounds for
vehicles traveling on roads outside of the interstate system).\103\
---------------------------------------------------------------------------

    \103\ M.J. Bradley & Associates. Setting the Stage for
Regulation of Heavy-Duty Vehicle Fuel Economy and GHG Emissions:
Issues and Opportunities. February 2009. Page 35. Analysis based on
1992 Truck Inventory and Use Survey data, where the survey data
allowed developing the distribution of loads instead of merely the
average loads.
---------------------------------------------------------------------------

    As described above, the amount of payload that a tractor can carry
depends on the category (or GVWR and GCWR) of the vehicle. For example,
a typical Class 7 tractor can carry less payload than a Class 8
tractor. For proposal, the agencies used the Federal Highway
Administration Truck Payload Equivalent Factors using Vehicle Inventory
and Use Survey (VIUS) and Vehicle Travel Information System data to
determine the proposed payloads. FHWA's results found that the average
payload of a Class 8 vehicle ranged from 36,247 to 40,089 pounds,
depending on the average distance travelled per day.\104\ The same
results found that Class 7 vehicles carried between 18,674 and 34,210
pounds of payload also depending on average distance travelled per day.
Based on this data, the agencies proposed to prescribe a fixed payload
of 25,000 pounds for Class 7 tractors and 38,000 pounds for Class 8
tractors for their respective test procedures. The agencies proposed a
common payload for Class 8 day cabs and sleeper cabs as predefined GEM
input because the data available do not distinguish based on type of
Class 8 tractor. These payload values represent a heavily loaded
trailer, but not maximum GVWR, since as described above the majority of
tractors ``cube-out'' rather than ``weigh-out.''
---------------------------------------------------------------------------

    \104\ The U.S. Federal Highway Administration. Development of
Truck Payload Equivalent Factor. Table 11. Last viewed on March 9,
2010 at http://ops.fhwa.dot.gov/freight/freight_analysis/faf/faf2_reports/reports9/s510_11_12_tables.htm.
---------------------------------------------------------------------------

    The agencies developed the proposed tractor curb weight inputs from
actual tractor weights measured in two of EPA's test programs and based
on information from the manufacturers. The proposed trailer curb weight
inputs were derived from actual trailer weight measurements conducted
by EPA and weight data provided to ICF International by the trailer
manufacturers.\105\
---------------------------------------------------------------------------

    \105\ ICF International. Investigation of Costs for Strategies
to Reduce Greenhouse Gas Emissions for Heavy-Duty On-road Vehicles.
July 2010. Pages 4-15. Docket Number EPA-HQ-OAR-2010-0162-0044.
---------------------------------------------------------------------------

    The agencies received comments from UMTRI and ATA regarding the
values assumed for the combination tractor weights. UMTRI recommended
using 80,000 pounds for the total weight for tractor-trailer
combinations. ATA based on their analysis of the Federal Highway
Administration's Long Term Pavement Database, recommended 5,000 to
10,000 pound payload for Class 7 tractors and 25,000 to 30,000 pounds
for Class 8 tractors. ATA also determined from the same database that
20 percent of tractor miles are empty, 67 percent cube-out, and 13
percent weigh-out. The agencies are adopting the proposed tractor-
trailer weights because we do not have strong evidence to select other
values and because changing the assumed values would not change the
impact on GHG emissions or fuel consumption of the technologies
included in this phase of the HD program (the relative stringency of
the standards and the projected emission reductions do not change with
assumed payload). NHTSA and EPA intend to continue evaluating
additional sources of weight information in future phases of the
program.
    Details of the final individual weight inputs by regulatory
category, as shown in Table II-11, are included in RIA Chapter 3.

                                 Table II-11--Final Combination Tractor Weights
----------------------------------------------------------------------------------------------------------------
                                                                Tractor      Trailer                    Total
             Model type               Regulatory subcategory  tare weight     weight      Payload       weight
                                                                 (lbs)        (lbs)        (lbs)        (lbs)
----------------------------------------------------------------------------------------------------------------
Class 8.............................  Sleeper Cab High Roof.       19,000       13,500       38,000       70,500
Class 8.............................  Sleeper Cab Mid Roof..       18,750       10,000       38,000       66,750
Class 8.............................  Sleeper Cab Low Roof..       18,500       10,500       38,000       67,000
Class 8.............................  Day Cab High Roof.....       17,500       13,500       38,000       69,000
Class 8.............................  Day Cab Mid Roof......       17,100       10,000       38,000       65,100
Class 8.............................  Day Cab Low Roof......       17,000       10,500       38,000       65,500
Class 7.............................  Day Cab High Roof.....       11,500       13,500       25,000       50,000
Class 7.............................  Day Cab Mid Roof......       11,100       10,000       25,000       46,100
Class 7.............................  Day Cab Low Roof......       11,000       10,500       25,000       46,500
----------------------------------------------------------------------------------------------------------------

(iv) Standardized Drivetrain
    The agencies' assessment at proposal of the current vehicle
configuration process at the truck dealer's level was that the truck
companies provide tools to specify the proper drivetrain matched to the
buyer's specific circumstances. These dealer tools allow a significant
amount of customization for drive cycle and payload to provide the best
specification for each individual customer. The agencies are not
seeking to disrupt this process. Optimal drivetrain selection is
dependent on the engine, drive cycle (including vehicle speed and road
grade), and payload. Each combination of engine, drive cycle, and
payload has a single optimal transmission and final drive ratio. The
agencies received comments from ArvinMeritor and ICCT which suggested
that the agencies incorporate the actual drivetrain configuration (axle
configuration, driveline efficiency, and transmission) into the GEM.
The agencies continue to believe, and therefore are adopting as
proposed, that it is appropriate to specify the engine's fuel
consumption map, drive cycle, and payload; therefore, it makes sense to
also specify the drivetrain that matches.
(v) Engine Input to the GEM for Tractors
    As proposed, the agencies are defining the engine characteristics
used in the GEM, including the fuel consumption map which provides the
fuel consumption at hundreds of engine speed and torque points. If the
agencies did not standardize the fuel map, then a tractor that uses an
engine with emissions and fuel consumption better than the standards
would require fewer vehicle reductions than those technically feasible
reductions reflected in the final standards. The agencies are
finalizing two distinct fuel consumption maps for use in the GEM. The
first fuel

consumption map would be used in the GEM for the 2014 through 2016
model years and represents an average engine which meets EPA's final
2014 model year engine CO2 emissions standards. The same
fuel map would be used for NHTSA's voluntary standards in the 2014 and
2015 model years, as well as its mandatory program in the 2016 model
year. A second fuel consumption map will be used beginning in the 2017
model year and represents an engine which meets the 2017 model year
CO2 emissions and fuel consumption standards and accounts
for the increased stringency in the final MY 2017 standard. The
agencies have modified the 2017 MY fuel map used in the GEM for the
final rulemaking to address comments received. Details regarding this
change can be found in RIA Chapter 4.4.4. Effectively there is no
change in stringency of the tractor vehicle (not including the engine
standards over the full rulemaking period).\106\ These inputs are
appropriate given the separate regulatory requirement that Class 7 and
8 combination tractor manufacturers use only certified engines.
---------------------------------------------------------------------------

    \106\ As noted earlier, use of the 2017 model year fuel
consumption map as a GEM input results in numerically more stringent
final vehicle standards for MY 2017.
---------------------------------------------------------------------------

(i) Heavy-Duty Engine Test Procedure for Engines Installed in
Combination Tractors
    The HD engine test procedure consists of two primary aspects--a
duty cycle and a metric to evaluate the emissions and fuel consumption.
    EPA proposed that the GHG emission standards for heavy-duty engines
under the CAA would be expressed as g/bhp-hr while NHTSA's proposed
fuel consumption standards under EISA, in turn, be represented as gal/
100 bhp-hr. The NAS panel did not specifically discuss or recommend a
metric to evaluate the fuel consumption of heavy-duty engines. However,
as noted above they did recommend the use of a load-specific fuel
consumption metric for the evaluation of vehicles.\107\ An analogous
metric for engines is the amount of fuel consumed per unit of work. The
g/bhp-hr metric is also consistent with EPA's current standards for
non-GHG emissions for these engines. The agencies did not receive any
adverse comments related to the metrics for HD engines; therefore, we
are adopting the metrics as proposed.
---------------------------------------------------------------------------

    \107\ See NAS Report, Note 21, at page 39.
---------------------------------------------------------------------------

    The agencies believe it is appropriate to set standards based on a
single test procedure, either the Heavy-duty FTP or SET, depending on
the primary expected use of the engine. This approach differs from
EPA's criteria pollutant standards for engines which currently require
that manufacturers demonstrate compliance over the transient FTP cycle;
over the steady-state SET procedure; and during not-to-exceed testing.
EPA created this multi-layered approach to criteria emissions control
in response to engine designs that optimized operation for lowest fuel
consumption at the expense of very high criteria emissions when
operated off the regulatory cycle. EPA's use of multiple test
procedures for criteria pollutants helps to ensure that manufacturers
calibrate engine systems for compliance under all operating conditions.
We are not concerned if manufacturers further calibrate engines off-
cycle to give better in-use fuel consumption while maintaining
compliance with the criteria emissions standards as such calibration is
entirely consistent with the goals of our joint program. Further, we
believe that setting GHG and fuel consumption standards based on both
transient and steady-state operating conditions for all engines could
lead to undesirable outcomes.
    It is critical to set standards based on the most representative
test cycles in order for performance in-use to obtain the intended (and
feasible) air quality and fuel consumption benefits. Tractors spend the
majority of their operation at steady state conditions, and will obtain
in-use benefit of technologies such as turbocompounding and other waste
heat recovery technologies during this kind of typical engine
operation. Turbocompounding is a very effective approach to lower fuel
consumption under steady driving conditions typified by combination
tractor trailer operation and is well reflected in testing over the SET
test procedure. However, when used in driving typified by transient
operation as we expect for vocational vehicles and as is represented by
the Heavy-duty FTP, turbocompounding shows very little benefit. Setting
an emission standard based on the Heavy-duty FTP for engines intended
for use in combination tractor trailers could lead manufacturers to not
apply turbocompounding even though it can be a highly cost effective
means to reduce GHG emissions and lower fuel consumption. (It is for
this reason that turbocompounding is not part of the technology basis
for MHD or HHD engines installed in vocational vehicles.)
    The agencies proposed that engines installed in tractors
demonstrate compliance with the CO2 emissions and fuel
consumption standards over the SET cycle. Commenters such as Cummins,
Bosch, Daimler, and Honeywell supported the proposed approach. ACEEE
recommended adopting a new test cycle, such as the World Harmonized
Duty Cycle which was developed using newer data, to evaluate HD
engines. Daimler also supported the WHDC for future phases of the
program. The agencies continue to believe the important issues and
technical work related to setting new criteria pollutant emissions
standards appropriate for the World Harmonized Duty Cycle are
significant and beyond the scope of this rulemaking. The SET cycle
remains representative of typical driving cycles for combination
tractors (and engines installed in them). Therefore, the agencies are
adopting the SET cycle to evaluate CO2 emissions and fuel
consumption of HD engines installed in tractors, as proposed.
    The current non-GHG emissions engine test procedures also require
the development of regeneration emission rates and frequency factors to
account for the emission changes during a regeneration event (40 CFR
86.004-28). EPA and NHTSA proposed not to include these emissions from
the calculation of the compliance levels over the defined test
procedures. Cummins and Daimler supported this approach and stated that
sufficient incentives already exist for manufacturers to limit
regeneration frequency. Conversely, Volvo opposed the omission of IRAF
requirements for CO2 emissions because emissions from
regeneration can be a significant portion of the expected improvement
and a significant variable between manufacturers
    At proposal, we considered including regeneration in the estimate
of fuel consumption and GHG emissions and decided not to do so for two
reasons. See 75 FR at 74188. First, EPA's existing criteria emission
regulations already provide a strong motivation to engine manufacturers
to reduce the frequency and duration of infrequent regeneration events.
The very stringent 2010 NOX emission standards cannot be met
by engine designs that lead to frequent and extend regeneration events.
Hence, we believe engine manufacturers are already reducing
regeneration emissions to the greatest degree possible. In addition to
believing that regenerations are already controlled to the extent
technologically possible, we believe that attempting to include
regeneration emissions in the standard setting could lead to an
inadvertently lax emissions standard. In order to include regeneration
and set appropriate standards, EPA and NHTSA would have needed to
project the regeneration

frequency and duration of future engine designs in the time frame of
this program. Such a projection would be inherently difficult to make
and quite likely would underestimate the progress engine manufacturers
will make in reducing infrequent regenerations. If we underestimated
that progress, we would effectively be setting a more lax set of
standards than otherwise would be expected. Hence in setting a standard
including regeneration emissions we faced the real possibility that we
would achieve less effective CO2 emissions control and fuel
consumption reductions than we will achieve by not including
regeneration emissions. Therefore, the agencies are finalizing an
approach as proposed which does not include the regenerative emissions.
(j) Chassis-Based Test Procedure
    In the proposal, the agencies considered proposing a chassis-based
vehicle test to evaluate Class 7 and 8 tractors based on a laboratory
test of the engine and vehicle together. A ``chassis dynamometer test''
for heavy-duty vehicles would be similar to the Federal Test Procedure
used today for light-duty vehicles.
    However, the agencies decided not to propose the use of a chassis
test procedure to demonstrate compliance for tractor standards due to
the significant technical hurdles to implementing such a program by the
2014 model year. The agencies recognize that such testing requires
expensive, specialized equipment that is not yet widespread within the
industry. The agencies have only identified approximately 11 heavy-duty
chassis sites in the United States today and rapid installation of new
facilities to comply with model year 2014 is not possible.\108\
---------------------------------------------------------------------------

    \108\ For comparison, engine manufacturers typically own a large
number of engine dynamometer test cells for engine development and
durability (up to 100 engine dynamometers per manufacturer).
---------------------------------------------------------------------------

    In addition, and of equal if not greater importance, because of the
enormous numbers of vehicle configurations that have an impact on fuel
consumption, we do not believe that it would be reasonable to require
testing of many combinations of tractor model configurations on a
chassis dynamometer. The agencies evaluated the options available for
one tractor model (provided as confidential business information from a
truck manufacturer) and found that the company offered three cab
configurations, six axle configurations, five front axles, 12 rear
axles, 19 axle ratios, eight engines, 17 transmissions, and six tire
sizes--where each of these options could impact the fuel consumption
and CO2 emissions of the tractor. Even using representative
grouping of tractors for purposes of certification, this presents the
potential for many different combinations that would need to be tested
if a standard were adopted based on a chassis test procedure.
    The agencies received comments from ACEEE and UCS supporting a full
vehicle testing approach, but these commenters recognized the
difficulties in doing this in the first phase of the HD program. The
agencies maintain that the full vehicle testing on chassis dynamometers
is not feasible in the timeframe of this rulemaking, although we
believe such an approach may be appropriate in the future, if more
testing facilities become available and if the agencies are able to
address the complexity of tractor configurations issue described above.
(4) Summary of Flexibility and Credit Provisions for Tractors and
Engine Used in These Tractors
    EPA and NHTSA are finalizing four flexibility provisions
specifically for heavy-duty tractor and engine manufacturers, as
discussed in Section IV below. These are an averaging, banking and
trading program for emissions and fuel consumption credits, as well as
provisions for early credits, advanced technology credits, and credits
for innovative vehicle or engine technologies which are not included as
inputs to the GEM or are not demonstrated on the engine SET test cycle.
With the exception of the advanced technology credits, credits
generated under these provisions can only be used within the same
averaging set which generated the credit (for example, credits
generated by HD engines installed in tractors can only be used by HD
engines). EPA is also adopting a N2O emission credit
program, as described in Section IV below.
(5) Deferral of Standards for Tractor and Engine Manufacturing
Companies That Are Small Businesses
    EPA and NHTSA are not adopting greenhouse gas emissions and fuel
consumption standards for small tractor or engine manufacturers meeting
the Small Business Administration (SBA) size criteria of a small
business as described in 13 CFR 121.201.\109\ The agencies will instead
consider appropriate GHG and fuel consumption standards for these
entities as part of a future regulatory action. This includes both
U.S.-based and foreign small volume heavy-duty tractor and engine
manufacturers.
---------------------------------------------------------------------------

    \109\ See Sec.  1036.150 and Sec.  1037.150.
---------------------------------------------------------------------------

    The agencies have identified two entities that fit the SBA size
criterion of a small business.\110\ The agencies estimate that these
small entities comprise less than 0.5 percent of the total heavy-duty
combination tractors in the United States based on Polk Registration
Data from 2003 through 2007,\111\ and therefore that the exemption will
have a negligible impact on the GHG emissions and fuel consumption
improvements from the final standards.
---------------------------------------------------------------------------

    \110\ The agencies have identified Ottawa Truck, Inc. and Kalmar
Industries USA as two potential small tractor manufacturers.
    \111\ M.J. Bradley. Heavy-duty Vehicle Market Analysis. May
2009.
---------------------------------------------------------------------------

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

C. Heavy-Duty Pickup Trucks and Vans

    The primary elements of the EPA and NHTSA programs for complete HD
pickups and vans are presented in this section. These provisions also
cover optional chassis certification of incomplete HD vehicles and of
Class 4 and 5 vehicles, as discussed in detail in Section V.B(1)(e).
Section II.C(1) explains the form of the CO2 and fuel
consumption standards, the numerical levels for those standards, and
the approach to phasing in the standards over time. The measurement
procedure for determining compliance is discussed in Section II.C(2),
and the EPA and NHTSA compliance programs are discussed in Section
II.C(3). Section II.C(4) discusses implementation flexibility
provisions. Section II.E discusses additional standards and provisions
for N2O and CH4 emissions, for vehicle air
conditioning leakage, and for ethanol-fueled and electric vehicles. HD
pickup and van air conditioning efficiency is not being regulated, for
reasons discussed in Section II.E.
(1) What are the levels and timing of HD pickup and van standards?
(a) Vehicle-Based Standards
    About 90 percent of Class 2b and 3 vehicles are pickup trucks,
passenger vans, and work vans that are sold by the original equipment
manufacturers as complete vehicles, ready for use on the road. In
addition, most of these

complete HD pickups and vans are covered by CAA vehicle emissions
standards for criteria pollutants today (i.e., they are chassis tested
similar to light-duty), expressed in grams per mile. This distinguishes
this category from other, larger heavy-duty vehicles that typically
have only the engines covered by CAA engine emission standards,
expressed in grams per brake horsepower-hour. As a result, Class 2b and
3 complete vehicles share much more in common with light-duty trucks
than with other heavy-duty vehicles.
    Three of these commonalities are especially significant: (1) Over
95 percent of the HD pickups and vans sold in the United States are
produced by Ford, General Motors, and Chrysler--three companies with
large light-duty vehicle and light-duty truck sales in the United
States, (2) these companies typically base their HD pickup and van
designs on higher sales volume light-duty truck platforms and
technologies, often incorporating new light-duty truck design features
into HD pickups and vans at their next design cycle, and (3) at this
time most complete HD pickups and vans are certified to vehicle-based
rather than engine-based EPA standards. There is also the potential for
substantial GHG and fuel consumption reductions from vehicle design
improvements beyond engine changes (such as through optimizing
aerodynamics, weight, tires, and accessories), and the manufacturer is
generally responsible for both engine and vehicle design. All of these
factors together suggest that it is appropriate and reasonable to set
standards for the vehicle as a whole, rather than to establish separate
engine and vehicle GHG and fuel consumption standards, as is being done
for the other heavy-duty categories. This approach for complete
vehicles is consistent with Recommendation 8-1 of the NAS Report, which
encourages the regulation of ``the final stage vehicle manufacturers
since they have the greatest control over the design of the vehicle and
its major subsystems that affect fuel consumption.'' There was
consensus in the public comments supporting this approach.
(b) Work-Based Attributes
    In setting heavy-duty vehicle standards it is important to take
into account the great diversity of vehicle sizes, applications, and
features. That diversity reflects the variety of functions performed by
heavy-duty vehicles, and this in turn can affect the kind of technology
that is available to control emissions and reduce fuel consumption, and
its effectiveness. EPA has dealt with this diversity in the past by
making weight-based distinctions where necessary, for example in
setting HD vehicle standards that are different for vehicles above and
below 10,000 lb GVWR, and in defining different standards and useful
life requirements for light-, medium-, and heavy-heavy-duty engines.
Where appropriate, distinctions based on fuel type have also been made,
though with an overall goal of remaining fuel-neutral.
    The joint EPA GHG and NHTSA fuel economy rules for light-duty
vehicles accounted for vehicle diversity in that segment by basing
standards on vehicle footprint (the wheelbase times the average track
width). Passenger cars and light trucks with larger footprints are
assigned numerically higher target levels for GHGs and numerically
lower target levels for fuel economy in acknowledgement of the
differences in technology as footprint gets larger, such that vehicles
with larger footprints have an inherent tendency to burn more fuel and
emit more GHGs per mile of travel. Using a footprint-based attribute to
assign targets also avoids interfering with the ability of the market
to offer a variety of products to maintain consumer choice.
    In developing this rulemaking, the agencies emphasized creating a
program structure that would achieve reductions in fuel consumption and
GHGs based on how vehicles are used and on the work they perform in the
real world, consistent with the NAS report recommendations to be
mindful of HD vehicles' unique purposes. Despite the HD pickup and van
similarities to light-duty vehicles, we believe that the past practice
in EPA's heavy-duty program of using weight-based distinctions in
dealing with the diversity of HD pickup and van products is more
appropriate than using vehicle footprint. Work-based measures such as
payload and towing capability are key among the things that
characterize differences in the design of vehicles, as well as
differences in how the vehicles will be used. Vehicles in this category
have a wide range of payload and towing capacities. These work-based
differences in design and in-use operation are the key factors in
evaluating technological improvements for reducing CO2
emissions and fuel consumption. Payload has a particularly important
impact on the test results for HD pickup and van emissions and fuel
consumption, because testing under existing EPA procedures for criteria
pollutants is conducted with the vehicle loaded to half of its payload
capacity (rather than to a flat 300 lb as in the light-duty program),
and the correlation between test weight and fuel use is strong.\112\
---------------------------------------------------------------------------

    \112\ Section II.C(2) discusses our decision that GHGs and fuel
consumption for HD pickups and vans be measured using the same test
conditions as in the existing EPA program for criteria pollutants.
---------------------------------------------------------------------------

    Towing, on the other hand, does not directly factor into test
weight as nothing is towed during the test. Hence only the higher curb
weight caused by heavier truck components would play a role in
affecting measured test results. However towing capacity can be a
significant factor to consider because HD pickup truck towing
capacities can be quite large, with a correspondingly large effect on
design.
    We note too that, from a purchaser perspective, payload and towing
capability typically play a greater role than physical dimensions in
influencing purchaser decisions on which heavy-duty vehicle to buy. For
passenger vans, seating capacity is of course a major consideration,
but this correlates closely with payload weight.
    Although heavy-duty vehicles are traditionally classified by their
GVWR, we do not believe that GVWR is the best weight-based attribute on
which to base GHG and fuel consumption standards for this group of
vehicles. GVWR is a function of not only payload capacity but of
vehicle curb weight as well; in fact, it is the simple sum of the two.
Allowing more GHG emissions from vehicles with higher curb weight tends
to penalize lightweighted vehicles with comparable payload capabilities
by making them meet more stringent standards than they would have had
to meet without the weight reduction. The same would be true for
another common weight-based measure, the gross vehicle combination
weight, which adds the maximum combined towing and payload weight to
the curb weight.
    Similar concerns about using weight-based attributes that include
vehicle curb weight were raised in the EPA/NHTSA proposal for light-
duty GHG and fuel economy standards: ``footprint-based standards
provide an incentive to use advanced lightweight materials and
structures that would be discouraged by weight-based standards'', and
``there is less risk of `gaming' (artificial manipulation of the
attribute(s) to achieve a more favorable target) by increasing
footprint under footprint-based standards than by increasing vehicle
mass under weight-based standards--it is relatively easy for a
manufacturer to add enough weight to a vehicle to decrease its
applicable fuel economy target a significant amount, as compared to
increasing vehicle footprint'' (74 FR 49685, September 28,

2009). The agencies believe that using payload and towing capacities as
the work-based attributes avoids the above-mentioned disincentive for
the use of lightweighting technology by taking vehicle curb weight out
of the standards determination.
    After taking these considerations into account, EPA and NHTSA
proposed to set standards for HD pickups and vans based on the proposed
``work factor'' attribute that combines vehicle payload capacity and
vehicle towing capacity, in pounds, with an additional fixed adjustment
for four-wheel drive (4wd) vehicles. This adjustment accounts for the
fact that 4wd, critical to enabling the many off-road heavy-duty work
applications, adds roughly 500 lb to the vehicle weight. There was
consensus in the public comments supporting this attribute, and the
agencies are adopting it as proposed. Target GHG and fuel consumption
standards will be determined for each vehicle with a unique work factor
(analogous to a target for each discrete vehicle footprint in the
light-duty vehicle rules). These targets will then be production
weighted and summed to derive a manufacturer's annual fleet average
standard for its heavy-duty pickups and vans. Widespread support for
the proposed work factor-based approach to standards and fleet average
approach to compliance was expressed in the comments we received.
    To ensure consistency and help preclude gaming, we are finalizing
the proposed provision that payload capacity be defined as GVWR minus
curb weight, and towing capacity as GCWR minus GVWR. For purposes of
determining the work factor, GCWR is defined according to the Society
of Automotive Engineers (SAE) Recommended Practice J2807 APR2008, GVWR
is defined consistent with EPA's criteria pollutants program, and curb
weight is defined as in 40 CFR 86.1803-01. Based on analysis of how
CO2 emissions and fuel consumption correlate to work factor,
we believe that a straight line correlation is appropriate across the
spectrum of possible HD pickups and vans, and that vehicle distinctions
such as Class 2b versus Class 3 need not be made in setting standards
levels for these vehicles.\113\ This approach was supported by
commenters.
---------------------------------------------------------------------------

    \113\ Memorandum from Anthony Neam and Jeff Cherry, U.S.EPA, to
docket EPA-HQ-OAR-2010-0162, October 18, 2010.
---------------------------------------------------------------------------

    We note that payload/towing-dependent gram per mile and gallon per
100 mile standards for HD pickups and vans parallel the gram per ton-
mile and gallon per 1,000 ton-mile standards being finalized for Class
7 and 8 combination tractors and for vocational vehicles. Both
approaches account for the fact that more work is done, more fuel is
burned, and more CO2 is emitted in moving heavier loads than
in moving lighter loads. Both of these load-based approaches avoid
penalizing vehicle designers wishing to reduce GHG emissions and fuel
consumption by reducing the weight of their trucks. However, the
sizeable diversity in HD work truck and van applications, which go well
beyond simply transporting freight, and the fact that the curb weights
of these vehicles are on the order of their payload capacities, suggest
that setting simple gram/ton-mile and gallon/ton-mile standards for
them is not appropriate. Even so, we believe that our setting of
payload-based standards for HD pickups and vans is consistent with the
NAS Report's recommendation in favor of load-specific fuel consumption
standards. Again, commenters agreed with this approach to setting HD
pickup and van standards.
    These attribute-based CO2 and fuel consumption standards
are meant to be relatively consistent from a stringency perspective.
Vehicles across the entire range of the HD pickup and van segment have
their respective target values for CO2 emissions and fuel
consumption, and therefore all HD pickups and vans will be affected by
the standard. With this attribute-based standards approach, EPA and
NHTSA believe there should be no significant effect on the relative
distribution of vehicles with differing capabilities in the fleet,
which means that buyers should still be able to purchase the vehicle
that meets their needs.
(c) Standards
    The agencies are finalizing standards based on a technology
analysis performed by EPA to determine the appropriate HD pickup and
van standards. This analysis, described in detail in RIA Chapter 2,
considered:
     The level of technology that is incorporated in current
new HD pickups and vans,
     The available data on corresponding CO2
emissions and fuel consumption for these vehicles,
     Technologies that would reduce CO2 emissions
and fuel consumption and that are judged to be feasible and appropriate
for these vehicles through the 2018 model year,
     The effectiveness and cost of these technologies for HD
pickup and vans,
     Projections of future U.S. sales for HD pickup and vans,
and
     Forecasts of manufacturers' product redesign schedules.
    Based on this analysis, EPA is finalizing the proposed
CO2 attribute-based target standards shown in Figure 0-2 and
II-3, and NHTSA is finalizing the equivalent attribute-based fuel
consumption target standards, also shown in Figure 0-2 and II-3,
applicable in model year 2018. These figures also shows phase-in
standards for model years before 2018, and their derivation is
explained below, along with alternative implementation schedules to
ensure equivalency between the EPA and NHTSA programs while meeting
respective statutory obligations. Also, for reasons discussed below,
the agencies proposed and are establishing separate targets for
gasoline-fueled (and any other Otto-cycle) vehicles and diesel-fueled
(and any other Diesel-cycle) vehicles. The targets will be used to
determine the production-weighted fleet average standards that apply to
the combined diesel and gasoline fleet of HD pickups and vans produced
by a manufacturer in each model year.

[GRAPHIC] [TIFF OMITTED] TR15SE11.002

    \114\ The NHTSA program provides voluntary standards for model
years 2014 and 2015. Target line functions for 2016-2018 are for the
second NHTSA alternative described in Section II.C(d)(ii).

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

[GRAPHIC] [TIFF OMITTED] TR15SE11.003

    Described mathematically, EPA's and NHTSA's target standards are
defined by the following formulae:
---------------------------------------------------------------------------

    \115\ The NHTSA program provides voluntary standards for model
years 2014 and 2015. Target line functions for 2016-2018 are for the
second NHTSA alternative described in Section II.C(d)(ii).

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

Where:

WF = Work Factor = [0.75 x (Payload Capacity + xwd)] + [0.25 x
Towing Capacity]
Payload Capacity = GVWR (lb) - Curb Weight (lb)
xwd = 500 lb if the vehicle is equipped with 4wd, otherwise equals 0
lb
Towing Capacity = GCWR (lb) - GVWR (lb)
Coefficients a, b, c, and d are taken from Table II-12 or Table II-
13.
---------------------------------------------------------------------------

    \116\ The NHTSA program provides voluntary standards for model
years 2014 and 2015. Target line functions for 2016-2018 are for the
second NHTSA alternative described in Section II.C(d)(ii).

 Table II-12--Coefficients for HD Pickup and Van Target Standards \116\
------------------------------------------------------------------------
           Model year                a        b          c          d
------------------------------------------------------------------------
                             Diesel Vehicles
------------------------------------------------------------------------
2014............................   0.0478      368     0.000470     3.61
2015............................   0.0474      366     0.000466     3.60
2016............................   0.0460      354     0.000452     3.48
2017............................   0.0445      343     0.000437     3.37
2018 and later..................   0.0416      320     0.000409     3.14
------------------------------------------------------------------------
                            Gasoline Vehicles
------------------------------------------------------------------------
2014............................   0.0482      371     0.000542     4.17
2015............................   0.0479      369     0.000539     4.15
2016............................   0.0469      362     0.000528     4.07
2017............................   0.0460      354     0.000518     3.98
2018 and later..................   0.0440      339     0.000495     3.81
------------------------------------------------------------------------

    Table II-13--Coefficients for NHTSA's First Alternative and EPA's
             Alternative HD Pickup and Van Target Standards
------------------------------------------------------------------------
           Model year                a        b          c          d
------------------------------------------------------------------------
                             Diesel Vehicles
------------------------------------------------------------------------
2014 a..........................   0.0478      368     0.000470     3.61
2015 a..........................   0.0474      366     0.000466     3.60
2016-2018.......................   0.0440      339     0.000432     3.33
2019 and later..................   0.0416      320     0.000409     3.14
------------------------------------------------------------------------
                            Gasoline Vehicles
------------------------------------------------------------------------
2014 a..........................   0.0482      371     0.000542     4.17
2015 a..........................   0.0479      369     0.000539     4.15
2016-2018.......................   0.0456      352     0.000513     3.96
2019 and later..................   0.0440      339     0.000495     3.81
------------------------------------------------------------------------
Notes:
a NHTSA standards will be voluntary in 2014 and 2015.

    These targets are based on a set of vehicle, engine, and
transmission technologies assessed by the agencies and determined to be
feasible and appropriate for HD pickups and vans in the 2014-2018
timeframe. See Section III.B for a detailed analysis of these vehicle,
engine and transmission technologies, including their feasibility,
costs, and effectiveness in HD pickups and vans.
    To calculate a manufacturer's HD pickup and van fleet average
standard, the agencies are requiring that separate target curves be
used for gasoline and diesel vehicles. The agencies estimate that in
2018 the target curves will achieve 15 and 10 percent reductions in
CO2 and fuel consumption for diesel and gasoline vehicles,
respectively, relative to a common baseline for current (model year
2010) HD pickup trucks and vans. An additional two percent reduction in
GHGs will be achieved by the direct air conditioning leakage standard
in the EPA standards. These reductions are based on the agencies'
assessment of the feasibility of incorporating technologies (which
differ significantly for gasoline and diesel powertrains) in the 2014-
2018 model years, and on the differences in relative efficiency in the
current gasoline and diesel vehicles. The resulting reductions
represent roughly equivalent stringency levels for gasoline and diesel
vehicles, which is important in ensuring our program maintains product
choices available to vehicle buyers.
    In written comments on the proposal, Cummins objected to setting
separate diesel and gasoline vehicle standards, on the basis that it
increases the burden for diesel engine manufacturers more than for
gasoline engine manufacturers, and thereby could shift market share
away from diesels. EMA argued for fuel-neutrality based on historical
precedent and the fact that GHGs emitted by one type of engine are no
different than those emitted by another type of engine. We believe that
both engine types have roughly equivalent redesign burdens as evidenced
by the feasibility and cost analysis in RIA Chapter 2. Also, even
though the emissions and fuel consumption reductions are expressed from
a common diesel/gasoline baseline in these final rules, the actual
starting base for diesels is at a lower level than for gasoline
vehicles. Other industry commenters, including those with sizeable
diesel sales, expressed general support for the standards. The agencies
agree that standards that do not distinguish between fuel types are
generally preferable where technological or market-based reasons do not
strongly argue otherwise. These technological differences exist
presently between gasoline and diesel engines for GHGs, as described
above. The agencies emphasize, however, that they are not committed to
perpetuating separate GHG standards for gasoline and diesel heavy-duty
vehicles and engines, and expect to reexamine the need for separate
gasoline/diesel standards in the next rulemaking.
    Environmental groups and others commented that the proposed
standards were not stringent enough, citing the heavy-duty vehicle NAS
study finding that technologies such as hybridization are feasible.
However, in the ambitious timeframe we are focusing on for these rules,
targeting as it does technologies implementable in the HD pickup and
van fleet starting in 2014 and phasing in with normal product redesign
cycles through 2018, our assessment shows that the standards we are
establishing are appropriate. More advanced technologies considered in
the NAS report would be appropriate for consideration in future
rulemaking activity. Additional conventional technologies identified by
commenters as promising in light-duty applications and potentially
useful for HD applications are discussed in RIA chapter 2.
    The NHTSA fuel consumption target curves and the EPA GHG target
curves are equivalent. The agencies established the target curves using
the direct relationship between fuel consumption and CO2
using conversion factors of 8,887 g CO2/gallon for gasoline
and 10,180 g CO2/gallon for diesel fuel.
    It is expected that measured performance values for CO2
will generally be equivalent to fuel consumption. However, as explained
below in Section 0, EPA is finalizing a provision for manufacturers to
use CO2 credits to help demonstrate compliance with
N2O and CH4 emissions standards, by expressing
any N2O and CH4 undercompliance in terms of their
CO2-equivalent and applying the needed CO2
credits. For test families that do not use this compliance alternative,
the measured performance values for CO2 and fuel consumption
will be equivalent because the same test runs and measurement data will
be used to determine both values, and calculated fuel consumption will
be based on the same conversion factors that are used to establish the
relationship between the CO2 and fuel consumption target
curves (8,887 g CO2/gallon for gasoline and 10,180 g
CO2/gallon for diesel fuel). For manufacturers that choose
to use the EPA provision for CO2 credit use in demonstrating
N2O and CH4 compliance, compliance with the
CO2 standard will not be directly equivalent to compliance
with the NHTSA fuel consumption standard.

(d) Implementation Plan
(i) EPA Program Phase-In MY 2014-2018
    EPA is finalizing the proposed provision that the GHG standards be
phased in gradually over the 2014-2018 model years, with full
implementation effective in the 2018 model year. Therefore, 100 percent
of a manufacturer's vehicle fleet will need to meet a fleet-average
standard that will become increasingly more stringent each year of the
phase-in period. For both gasoline and diesel vehicles, this phase-in
will be 15-20-40-60-100 percent of the model year 2018 stringency in
model years 2014-2015-2016-2017-2018, respectively. These percentages
reflect stringency increases from a baseline performance level for
model year 2010, determined by the agencies based on EPA and
manufacturer data. Because these vehicles are not currently regulated
for GHG emissions, this phase-in takes the form of target line
functions for gasoline and diesel vehicles that become increasingly
stringent over the phase-in model years. These year-by-year functions
have been derived in the same way as the 2018 function, by taking a
percent reduction in CO2 from a common unregulated baseline.
For example, in 2014 the reduction for both diesel and gasoline
vehicles will be 15 percent of the fully-phased-in reductions. Figures
II-2 and II-3, and Table 0-12, reflect this phase-in approach.
    EPA is also providing manufacturers with an optional alternative
implementation schedule in model years 2016 through 2018, equivalent to
NHTSA's first alternative for standards that do not change over these
model years, described below. Under this option the phase-in will be
15-20-67-67-67-100 percent of the model year 2019 stringency in model
years 2014-2015-2016-2017-2018-2019, respectively. Table 0-13, above,
provides the coefficients ``a'' and ``b'' for this manufacturer's
alternative. As explained below, this alternative will provide roughly
equivalent overall CO2 reductions and fuel consumption
improvements as the 15-20-40-60-100 percent phase-in. In addition, as
explained below, the stringency of this alternative was established by
NHTSA such that a manufacturer with a stable production volume and mix
over the model year 2016-2018 period could use Averaging, Banking and
Trading to comply with either alternative and have a similar credit
balance at the end of model year 2018.
    Under the above-described alternatives, each manufacturer will need
to demonstrate compliance with the applicable fleet average standard
using that year's target function over all of its HD pickups and vans
starting with its MY 2014 fleet of HD pickups and vans. No comments
were received in support of an alternative approach that EPA requested
comment on, involving phasing in an annually increasing percentage of
each manufacturer's sales volume.
(ii) NHTSA Program Phase-In 2016 and Later
    NHTSA is finalizing the proposed provision to allow manufacturers
to select one of two fuel consumption standard alternatives for model
years 2016 and later. Each manufacturer will select an alternative in
its joint pre-model year report, discussed below, that is now required
to be electronically submitted to the agencies; and, once selected, the
alternative will apply for model years 2016 and later, and cannot be
reversed. The first alternative will define a fuel consumption target
line function for gasoline vehicles and a target line function for
diesel vehicles that will not change for model years 2016 to 2018. The
target line function coefficients are provided in Table II-13.
    The second alternative will be equivalent to the EPA target line
functions in each model year starting in 2016 and continuing
afterwards. Stringency of fuel consumption standards will increase
gradually for the 2016 and later model years. Relative to a model year
2010 unregulated baseline for both gasoline and diesel vehicles,
stringency will be 40, 60, and 100 percent of the 2018 target line
function in model years 2016, 2017, and 2018, respectively. The
stringency of the target line functions in the first alternative for
model years 2016-2017-2018-2019 is 67-67-67-100 percent, respectively,
of the 2019 stringency in the second alternative. The stringency of the
first alternative was established so that a manufacturer with a stable
production volume and mix over the model year 2016-2018 period could
use Averaging, Banking and Trading to comply with either alternative
and have a similar credit balance at the end of model year 2018 under
the EPA and NHTSA programs.
(iii) NHTSA Voluntary Standards Period
    NHTSA is finalizing the proposed provision that manufacturers may
voluntarily opt into the NHTSA HD pickup and van program in model years
2014 or 2015. If a manufacturer elects to opt in to the program, it
must stay in the program for all the optional model years.
Manufacturers that opt in become subject to NHTSA standards for all
regulatory categories. To opt into the program, a manufacturer must
declare its intent to opt in to the program in its Pre-Model Year
Report. The agencies have finalized new requirements for manufacturers
to provide all early model declarations as a part of the pre-model year
reports. See regulatory text for 49 CFR 535.8 for information related
to the Pre-Model Year Report. A manufacturer would begin tracking
credits and debits beginning in the model year in which they opt into
the program. The handling of credits and debits would be the same as
for the mandatory program.
    For manufacturers that opt into NHTSA's HD pickup and van fuel
consumption program in 2014 or 2015, the stringency would increase
gradually each model year. Relative to a model year 2010 unregulated
baseline, for both gasoline and diesel vehicles, stringency would be
15-20 percent of the model year 2019 target line function stringency
(under the NHTSA first alternative) and 15-20 percent of the model year
2018 target line function stringency (under the NHTSA second
alternative) in model years 2014-2015, respectively. The corresponding
absolute standards target levels are provided in Figure II-2 and II-3,
and the accompanying equations.
(2) What are the HD pickup and van test cycles and procedures?
    EPA and NHTSA are finalizing the proposed provision that HD pickup
and van testing be conducted using the same heavy-duty chassis test
procedures currently used by EPA for measuring criteria pollutant
emissions from these vehicles, but with the addition of the highway
fuel economy test cycle (HFET) currently required only for light-duty
vehicle GHG emissions and fuel economy testing. Although the highway
cycle driving pattern is identical to that of the light-duty test,
other test parameters for running the HFET, such as test vehicle loaded
weight, are identical to those used in running the current EPA Federal
Test Procedure for complete heavy-duty vehicles.
    The GHG and fuel consumption results from vehicle testing on the
Light-duty FTP and the HFET will be weighted by 55 percent and 45
percent, respectively, and then averaged in calculating a combined
cycle result. This result corresponds with the data used to develop the
work factor-based CO2 and fuel consumption standards, since
the data on the baseline and technology efficiency was also

developed in the context of these test procedures. The addition of the
HFET and the 55/45 cycle weightings are the same as for the light-duty
CO2 and CAFE programs, as we believe the real world driving
patterns for HD pickups and vans are not too unlike those of light-duty
trucks, and we are not aware of data specifically on these patterns
that would lead to a different choice of cycles and weightings, nor did
any commenters provide such data. More importantly, we believe that the
55/45 weightings will provide for effective reductions of GHG emissions
and fuel consumption from these vehicles, and that other weightings,
even if they were to more precisely match real world patterns, are not
likely to significantly improve the program results.
    Another important parameter in ensuring a robust test program is
vehicle test weight. Current EPA testing for HD pickup and van criteria
pollutants is conducted with the vehicle loaded to its Adjusted Loaded
Vehicle Weight (ALVW), that is, its curb weight plus [frac12] of the
payload capacity. This is substantially more challenging than loading
to the light-duty vehicle test condition of curb weight plus 300
pounds, but we believe that this loading for HD pickups and vans to
[frac12] payload better fits their usage in the real world and will
help ensure that technologies meeting the standards do in fact provide
real world reductions. The choice is likewise consistent with use of an
attribute based in considerable part on payload for the standard. We
see no reason to set test load conditions differently for GHGs and fuel
consumption than for criteria pollutants, and we are not aware of any
new information (such as real world load patterns) since the ALVW was
originally set this way that would support a change in test loading
conditions, nor did any commenters provide such information. We are
therefore using ALVW for test vehicle loading in GHG and fuel
consumption testing.
    Additional provisions for our final testing and compliance program
are provided in Section V.B.
(3) How are the HD pickup and van standards structured?
    EPA and NHTSA are finalizing the proposed fleet average standards
for new HD pickups and vans, based on a manufacturer's new vehicle
fleet makeup. In addition, EPA is finalizing proposed in-use standards
that apply to the individual vehicles in this fleet over their useful
lives. The compliance provisions for these fleet average and in-use
standards for HD pickups and vans are largely based on the recently
promulgated light-duty GHG and fuel economy program, as described in
detail in the proposal.
(a) Fleet Average Standards
    In the programs we are finalizing, each manufacturer will have a
GHG standard and a fuel consumption standard unique to its new HD
pickup and van fleet in each model year, depending on the load
capacities of the vehicle models produced by that manufacturer, and on
the U.S.-directed production volume of each of those models in that
model year. Vehicle models with larger payload/towing capacities have
individual targets at numerically higher CO2 and fuel
consumption levels than lower payload/towing vehicles, as discussed in
Section II.C(1). The fleet average standard for a manufacturer is a
production-weighted average of the work factor-based targets assigned
to unique vehicle configurations within each model type produced by the
manufacturer in a model year.
    The fleet average standard with which the manufacturer must comply
is based on its final production figures for the model year, and thus a
final assessment of compliance will occur after production for the
model year ends. Because compliance with the fleet average standards
depends on actual test group production volumes, it is not possible to
determine compliance at the time the manufacturer applies for and
receives an EPA certificate of conformity for a test group. Instead, at
certification the manufacturer will demonstrate a level of performance
for vehicles in the test group, and make a good faith demonstration
that its fleet, regrouped by unique vehicle configurations within each
model type, is expected to comply with its fleet average standard when
the model year is over. EPA will issue a certificate for the vehicles
covered by the test group based on this demonstration, and will include
a condition in the certificate that if the manufacturer does not comply
with the fleet average, then production vehicles from that test group
will be treated as not covered by the certificate to the extent needed
to bring the manufacturer's fleet average into compliance. As in the
light-duty program, additional ``model type'' testing will be conducted
by the manufacturer over the course of the model year to supplement the
initial test group data. The emissions and fuel consumption levels of
the test vehicles will be used to calculate the production-weighted
fleet averages for the manufacturer, after application of the
appropriate deterioration factor to each result to obtain a full useful
life value. See generally 75 FR 25470-25472.
    EPA and NHTSA do not currently anticipate notable deterioration of
CO2 emissions and fuel consumption performance, and are
therefore requiring that an assigned deterioration factor be applied at
the time of certification: an additive assigned deterioration factor of
zero, or a multiplicative factor of one will be used. EPA and NHTSA
anticipate that the deterioration factor may be updated from time to
time, as new data regarding emissions deterioration for CO2
are obtained and analyzed. Additionally, EPA and NHTSA may consider
technology-specific deterioration factors, should data indicate that
certain control technologies deteriorate differently than others. See
also 75 FR 25474.
(b) In-Use Standards
    Section 202(a)(1) of the CAA specifies that EPA set emissions
standards that are applicable for the useful life of the vehicle. The
in-use standards that EPA is finalizing apply to individual vehicles.
NHTSA is not adopting in-use standards because they are not required
under EISA, and because it is not currently anticipated that there will
be any notable deterioration of fuel consumption. For the EPA program,
compliance with the in-use standard for individual vehicles and vehicle
models will not impact compliance with the fleet average standard,
which will be based on the production-weighted average of the new
vehicles.
    EPA is finalizing the proposed provision that the in-use standards
for HD pickups and vans be established by adding an adjustment factor
to the full useful life emissions and fuel consumption results used to
calculate the fleet average. EPA is also finalizing the proposed
provision that the useful life for these vehicles with respect to GHG
emissions be set equal to their useful life for criteria pollutants: 11
years or 120,000 miles, whichever occurs first (40 CFR 86.1805-04(a)).
    As discussed above, we are finalizing the proposed provision that
certification test results obtained before and during the model year be
used directly to calculate the fleet average emissions for assessing
compliance with the fleet average standard. Therefore, this assessment
and the fleet average standard itself do not take into account test-to-
test variability and production variability that can affect measured
in-use levels. For this reason, EPA is finalizing the proposed
adjustment factor for the in-use standard to provide some margin for
production and test-to-

test variability that could result in differences between the initial
emission test results used to calculate the fleet average and emission
results obtained during subsequent in-use testing. EPA is finalizing
the proposed provision that each model's in-use CO2 standard
be the model-specific level used in calculating the fleet average, plus
10 percent. This is the same as the approach taken for light-duty
vehicle GHG in-use standards (See 75 FR 25473-25474). No adverse
comments were received on this proposed provision.
    As it does now for heavy-duty vehicle criteria pollutants, EPA will
use a variety of mechanisms to conduct assessments of compliance with
the in-use standards, including pre-production certification and in-use
monitoring once vehicles enter customer service. The full useful life
in-use standards apply to vehicles that have entered customer service.
The same standards apply to vehicles used in pre-production and
production line testing, except that deterioration factors are not
applied.
(4) What HD pickup and van flexibility provisions are being
established?
    This program contains substantial flexibility in how manufacturers
can choose to implement the EPA and NHTSA standards while preserving
their timely benefits for the environment and energy security. Primary
among these flexibilities are the gradual phase-in schedule,
alternative compliance paths, and corporate fleet average approach
which encompasses averaging, banking and trading described above.
Additional flexibility provisions are described briefly here and in
more detail in Section IV.
    As explained in Section II.C(3), we are finalizing the proposed
provision that, at the end of each model year, when production for the
model year is complete, a manufacturer calculate its production-
weighted fleet average CO2 and fuel consumption. Under this
approach, a manufacturer's HD pickup and van fleet that achieves a
fleet average CO2 or fuel consumption level better than its
standard will be allowed to generate credits. Conversely, if the fleet
average CO2 or fuel consumption level does not meet its
standard, the fleet would incur debits (also referred to as a
shortfall).
    A manufacturer whose fleet generates credits in a given model year
will have several options for using those credits to offset emissions
from other HD pickups and vans. These options include credit carry-
back, credit carry-forward, and credit trading. These provisions exist
in the light-duty 2012-2016 MY vehicle rule, and similar provisions are
part of EPA's Tier 2 program for light-duty vehicle criteria pollutant
emissions, as well as many other mobile source standards issued by EPA
under the CAA. The manufacturer will be able to carry back credits to
offset a deficit that had accrued in a prior model year and was
subsequently carried over to the current model year, with a limitation
on the carry-back of credits to three model years, consistent with the
light-duty program. We are finalizing the proposed provision that,
after satisfying any need to offset pre-existing deficits, a
manufacturer may bank remaining credits for use in future years, with a
limitation on the carry-forward of credits to five model years. We are
also finalizing the proposed provision that manufacturers may certify
their HD pickup and van fleet a year early, in MY 2013, to generate
credits against the MY 2014 standards. This averaging, banking, and
trading program for HD pickups and vans is discussed in more detail in
Section IV.A. For reasons discussed in detail in that section, we are
not finalizing any credit transferability to or from other credit
programs or averaging sets.
    Consistent with the President's May 21, 2010, directive to promote
advanced technology vehicles and with the agencies' respective
statutory authorities, we are adopting flexibility provisions that
parallel similar provisions adopted in the light-duty program. These
include credits for advance technology vehicles such as electric
vehicles, and credits for innovative technologies that are shown by the
manufacturer to provide GHG and fuel consumption reductions in real
world driving, but not on the test cycle. See Section IV.B.

D. Class 2b-8 Vocational Vehicles

    Heavy-duty vehicles serve a vast range of functions including
service for urban delivery, refuse hauling, utility service, dump,
concrete mixing, transit service, shuttle service, school bus,
emergency, motor homes,\117\ and tow trucks to name only a small subset
of the full range of vehicles. The vehicles designed to serve these
functions are as unique as the jobs they do. They are vastly
different--one from the other--in size, shape and function. The
agencies were unable to develop a specific vehicle definition based on
the characteristics of these vehicles. Instead at proposal, we proposed
to define that Class 2b-8 vocational vehicles as all heavy-duty
vehicles which are not included in the Heavy-duty Pickup Truck and Van
or the Class 7 and 8 Tractor categories. In effect, we said everything
that is not a combination tractor or a pickup truck or van is a
vocational vehicle. We are finalizing that definition as proposed
reflecting the same challenges we faced at proposal regarding defining
the full range of heavy-duty vehicles. As at proposal, recreational
vehicles are included under EPA's standards but are not included under
NHTSA's final standards. The agencies note that we are adding
vocational tractors to the vocational vehicle category in the final
rulemaking, as described above in Section II.B.
---------------------------------------------------------------------------

    \117\ See above for discussion of applicability of NHTSA's
standards to non-commercial vehicles.
---------------------------------------------------------------------------

    The agencies proposed that Class 4 pickup trucks although similar
to Class 2b and 3 vehicles be included in the vocational vehicle
category. Comments from EMA, Cummins, NTEA and Navistar supported the
premise that Class 4 vehicles belong as part of the vocational vehicle
program because they are specifically designed and engineered to meet
vocational requirements. They stated that components such as
transmissions, axles, frames, and tires differ from the similar pickup
trucks and vans in the Class 2b and 3 market. We agree with commenters'
arguments that there are a number of important differences between the
Class 4 and Class 3 trucks it unreasonable to regulate Class 4 vehicles
under the standards for heavy duty pickups and vans. As a result, we
are keeping Class 4 vehicles in the vocational vehicle category, but
are allowing the optional chassis certification of Class 4 and 5
vehicles. (See Section V.B(1)(e)).
    As mentioned in Section I, vocational vehicles undergo a complex
build process. Often an incomplete chassis is built by a chassis
manufacturer with an engine purchased from an engine manufacturer and a
transmission purchased from another manufacturer. A body manufacturer
purchases an incomplete chassis which is then completed by attaching
the appropriate features to the chassis.
    The diversity in the vocational vehicle segment can be primarily
attributed to the variety of vehicle bodies rather than to the chassis.
For example, a body builder can build either a Class 6 bucket truck or
a Class 6 delivery truck from the same Class 6 chassis. The aerodynamic
difference between these two vehicles due to their bodies will lead to
different baseline fuel consumption and GHG emissions. However, the
baseline fuel consumption and emissions due to the components included
in the common chassis (such as the engine, drivetrain, frame, and

tires) will be the same between these two types of complete vehicles.
    The agencies face difficulties in establishing the baseline
CO2 and fuel consumption performance for the wide variety of
complete vocational vehicles because of the very large number of
vehicle types and the need to conduct testing on each of the vehicle
types to establish the baseline. To establish standards for a complete
vocational vehicle, it would be necessary to assess the potential for
fuel consumption and GHG emissions improvement for each of these
vehicle types and to establish standards for each vehicle type. Because
of the size and complexity of this task, the agencies judged it was not
practical to regulate complete vocational vehicles for this first fuel
consumption and GHG emissions program. To overcome the lack of baseline
information from the different vehicle types and to still achieve
improvements to fuel consumption and GHG emissions, the agencies
proposed to set standards for the chassis manufacturers of vocational
vehicles (but not the body builders) and the engine manufacturers.
Chassis manufacturers represent a limited number of companies as
compared to body builders, which are made up of a diverse set of
companies that are typically small businesses. These companies would
need to be regulated if whole vehicle standards were established.
    Similar to combination tractors, the agencies proposed to set
separate vehicle and engine standards for vocational vehicles. A number
of comments were received on the proposal to regulate chassis and
engine manufacturers. The agencies received comments from DTNA
supporting the proposal to regulate the chassis manufacturer but not
body manufacturers. While organizations like Cummins and ICCT expressed
support for separate engine and vehicle standards, Navistar, Pew, and
Volvo, in contrast, opposed separate engine and chassis standards,
stating that separate engine standards disadvantages integrated truck/
engine manufacturers and full vehicle standards should be required.
Volvo asked that the standards include an alternative integrated
standard as well as complete vehicle modeling and testing beginning in
2017. ACEEE and Sierra Club stated that the proposed standards and test
procedures should move the agencies closer to full vehicle testing.
    Although the agencies understand that full vehicle standards would
allow integrated truck/engine manufacturers--such as electrified
accessories and weight reduction--the agencies are finalizing separate
standards for vocational vehicles that apply to chassis manufacturers
and engine standards for engines installed in these vehicles that apply
to engine manufacturers. The agencies continue to believe that it is
not practical to regulate complete vocational vehicles for this first
fuel consumption and GHG emissions program because of the size and
complexity of the task associated with assessing the potential for fuel
consumption and GHG emissions improvement for each of the myriad types
of vocational vehicles. This issue is discussed further in comment
responses found in sections 5 and 6.1.4 of the Response to Comment
Document, as well as in the following section of the preamble. Thus,
the agencies are finalizing a set of standards for the chassis
manufacturers of vocational vehicles (but not the body builders) and
for the manufacturers of HD engines used in vocational vehicles.
(1) What are the vocational vehicle and engine CO2 and fuel
consumption standards and their timing?
    In the NPRM, the agencies proposed vehicle standards based on the
agencies' assessment of the availability of low rolling resistance
tires that could be applied generally to vocational vehicles across the
entire category. The agencies considered the possibility of including
other technologies in determining the proposed stringency of the
vocational vehicle standards, such as aerodynamic improvements, but as
discussed in the NPRM, tentatively concluded that such improvements
would not be appropriate for basing vehicle standard stringency in this
phase of the rulemaking.\118\ For example, the aerodynamics of a
recovery vehicle are impacted significantly by the equipment such as
the arm located on the exterior of the truck.\119\ The agencies found
little opportunity to improve the aerodynamics of the equipment on the
truck. The agencies also evaluated the aerodynamic opportunities
discussed in the NAS report. The panel found that there was minimal
fuel consumption reduction opportunity through aerodynamic technologies
for bucket trucks, transit buses, and refuse trucks \120\ primarily due
to the low vehicle speed in normal operation. The panel did report that
there are opportunities to reduce the fuel consumption of straight
trucks by approximately 1 percent for trucks which operate at the
average speed typical of a pickup and delivery truck (30 mph), although
the opportunity is greater for vehicles that operate at higher
speeds.\121\
---------------------------------------------------------------------------

    \118\ See 75 FR at 74241.
    \119\ A recovery vehicle removes or recovers vehicles that are
disabled (broken down).
    \120\ See 2010 NAS Report, Note 21, page 133.
    \121\ See 2010 NAS Report, Note 21, page 110.
---------------------------------------------------------------------------

    The agencies received comments from the Motor Equipment
Manufacturers Association, Eaton, NRDC, NESCAUM, NACAA, ACEEE, ICCT,
Navistar, Arvin Meritor, the Union of Concerned Scientists and others
that technologies such as idle reduction, advanced transmissions,
advanced drivetrains, weight reduction, hybrid powertrains, and
improved auxiliaries provide opportunities to reduce fuel consumption
from vocational vehicles. Commenters asked that the agencies establish
regulations that would reflect performance of these technologies and
essentially force their utilization.
    The agencies assessed these technologies and have concluded that
they may have the potential to reduce fuel consumption and GHG
emissions from at least certain vocational vehicles, but the agencies
have not been able to estimate baseline fuel consumption and GHG
emissions levels for each type of vocational vehicle and for each type
of technology, given the wide variety of models and uses of vocational
vehicles. For example, idle reduction technologies such as APUs and
cabin heaters can reduce workday idling associated with vocational
vehicles. However, characterizing idling activity for the vocational
segment in order to quantify the benefits of idle reduction technology
is complicated by the variety of duty cycles found in the sector.
Idling in school buses, fire trucks, pickup trucks, delivery trucks,
and other types of vocational vehicles varies significantly. Given the
great variety of duty cycles and operating conditions of vocational
vehicles and the timing of these rules, it is not feasible at this time
to establish an accurate baseline for quantifying the expected
improvements which could result from use of idle reduction
technologies. Similarly, for advanced drivetrains and advanced
transmissions determining a baseline configuration, or a set of
baseline configurations, is extremely difficult given the variety of
trucks in this segment. The agencies do not believe that we can
legitimately base standard stringency on the use of technologies for
which we cannot identify baseline configurations, because absent
baseline emissions and baseline fuel consumption, the emissions
reductions achieved from introduction of the technology cannot be
quantified. For some technologies, such as weight

reduction and improved auxiliaries--such as electrically driven power
steering pumps and the vehicle's air conditioning system--the need to
limit technologies to those under the control of the chassis
manufacturer further restricted the agencies' options for predicating
standard stringency on use of these technologies. For example,
lightweight components that are under the control of chassis
manufacturers are limited to a very few components such as frame rails.
Considering the fuel efficiency and GHG emissions reduction benefits
that will be achieved by finalizing these rules in the time frame
proposed, rather than delaying in order to gain enough information to
include additional technologies, the agencies have decided to finalize
standards that do not assume the use of these technologies and will
consider incorporating them in a later action applicable to later model
years. Cf. Sierra Club v. EPA, 325 F. 3d 374, 380 (DC Cir. 2003) (in
implementing a technology-forcing provision of the CAA, EPA reasonably
adopted modest initial controls on an industry sector in order to
better assess rules' effects in preparation for follow-up rulemaking).
    As the program progresses and the agencies gather more information,
we expect to reconsider whether vocational vehicle standards for MYs
2019 and beyond should be based on the use of additional technologies
besides low rolling resistance tires.
    EPA is adopting CO2 standards and NHTSA is finalizing
fuel consumption standards for manufacturers of chassis for new
vocational vehicles and for manufacturers of heavy-duty engines
installed in these vehicles. The final heavy-duty engine standards for
CO2 emissions and fuel consumption focus on potential
technological improvements in fuel combustion and overall engine
efficiency and those controls would achieve most of the emission
reductions. Further reductions from the Class 2b-8 vocational vehicle
itself are possible within the time frame of these final regulations.
Therefore, the agencies are also finalizing separate standards for
vocational vehicles that will focus on additional reductions that can
be achieved through improvements in vehicle tires. The agencies'
analyses, as discussed briefly below and in more detail later in this
preamble and in the RIA Chapter 2, show that these final standards
appear appropriate under each agency's respective statutory
authorities. Together these standards are estimated to achieve
reductions of up to 10 percent from most vocational vehicles.
    EPA is also adopting standards to control N2O and
CH4 emissions from Class 2b-8 vocational vehicles through
controlling these GHG emissions from the HD engines. The final heavy-
duty engine standards for both N2O and CH4 and
details of the standard are included in the discussion in Section
II.E.1.b and II.E.2.b. EPA neither proposed nor is adopting air
conditioning leakage standards applying to vocational vehicle chassis
manufacturers.
    As discussed further below, the agencies are setting CO2
and fuel consumption standards for the chassis based on tire rolling
resistance improvements and for the engines based on engine
technologies. The fuel consumption and GHG emissions impact of tire
rolling resistance is impacted by the mass of the vehicle. However, the
impact of mass on rolling resistance is relatively small so the
agencies proposed to aggregate several vehicle weight categories under
a single category for setting the standards. The agencies proposed to
divide the vocational vehicle segment into three broad regulatory
subcategories--Light Heavy-Duty (Class 2b through 5), Medium Heavy-Duty
(Class 6 and 7), and Heavy Heavy-Duty (Class 8) which is consistent
with the nomenclature used in the diesel engine classification. The
agencies received comments supporting the division of vocational
vehicles into three regulatory categories from DTNA. The agencies also
received comments from Bosch, Clean Air Task Force, and National Solid
Waste Management Association supporting a finer resolution of
vocational vehicle subcategories. Their concerns include that the
agencies' vehicle configuration in GEM is not representative of a
particular vocational application, such as refuse trucks. Another
recommendation was to divide the category by both GVWR and by
operational characteristics. Upon further consideration, the agencies
are finalizing as proposed three vocational vehicle subcategories
because we believe this adequately balances simplicity while still
obtaining reductions in this diverse segment. (As noted in section IV.A
below, these three subcategories also denominate separate averaging
sets for purposes of ABT.) Finer distinctions in regulatory
subcategories would not change the technology basis for the standards
or the reductions expected from the vocational vehicle category. As the
agencies move towards future heavy-duty fuel consumption and GHG
regulations for post-2017 model years, we intend to gather GHG and fuel
consumption data for specific vocational applications which could be
used to establish application-specific standards in the future.
    The agencies received comments supporting the exclusion of
recreational vehicles, emergency vehicles, school buses from the
vocational vehicle standards. The commenters argued that these
individual vehicle types were small contributors to overall GHG
emissions and that tires meeting their particular performance needs
might not be available by 2014. The agencies considered these comments
and the agencies have met with a number of tire manufacturers to better
understand their expectations for product availability for the 2014
model year. Based on our review of the information shared, we are
convinced that tires with rolling resistance consistent with our final
vehicle standards and meeting the full range of other performance
characteristics desired in the vehicle market, including for RVs,
emergency vehicles, and school buses, will be broadly available by the
2014 model year.\122\ Absent regulations for the vast majority of
vehicles in this segment, feasible cost-effective reductions available
at reasonable cost in the 2014-2018 model years will be needlessly
foregone. Therefore, the agencies have decided to finalize the
vocational vehicle standards as proposed with recreational vehicles,
emergency vehicles and school buses included in the vocational vehicle
category. As RVs were not included by NHTSA for proposed regulation,
they are not within the scope of the NPRM and are therefore excluded in
NHTSA's portion of the final program. NHTSA will revisit this issue in
the next rulemaking. In developing the final standards, the agencies
have evaluated the current levels of emissions and fuel consumption,
the kinds of technologies that could be utilized by manufacturers to
reduce emissions and fuel consumption and the associated lead time, the
associated costs for the industry, fuel savings for the consumer, and
the magnitude of the CO2 and fuel savings that may be
achieved. After examining the possibility of vehicle improvements based
on use of the technologies underlying the standards for Class 7 and 8
tractors, including improved aerodynamics, vehicle speed limiters, idle
reduction technologies, tire rolling resistance, and weight reduction,
as well as use of hybrid technologies, the agencies ultimately

determined to base the final vehicle standards on performance of tires
with superior rolling resistance. For standards for diesel engines
installed in vocational vehicles, the agencies examined performance of
engine friction reduction, aftertreatment optimization, air handling
improvements, combustion optimization, turbocompounding, and waste heat
recovery, ultimately deciding to base the final standards on the
performance of all of the technologies except turbocompounding and
waste heat recovery systems. The standards for gasoline engine
installed in vocational vehicles are based on performance of
technologies such as gasoline direct injection, friction reduction, and
variable valve timing. The agencies' evaluation indicates that these
technologies, as described in Section III.C, are available today in the
heavy-duty tractor and light-duty vehicle markets, but have very low
application rates in the vocational vehicle market. The agencies have
analyzed the technical feasibility of achieving the CO2 and
fuel consumption standards, based on projections of what actions
manufacturers would be expected to take to reduce emissions and fuel
consumption to achieve the standards, and believe that the standards
are cost-effective and technologically feasible and appropriate within
the rulemaking time frame. EPA and NHTSA also present the estimated
costs and benefits of the vocational vehicle standards in Section III.
---------------------------------------------------------------------------

    \122\ Bachman, Joseph. Memorandum to the Docket. Heavy-Duty Tire
Evaluation. See Docket EPA-HQ-OAR-2010-0162. Pages 2-3 and
Appendix B.
---------------------------------------------------------------------------

(a) Vocational Vehicle Chassis Standards
    In the NPRM, the agencies defined tire rolling resistance as a
frictional loss of energy, associated mainly with the energy dissipated
in the deformation of tires under load that influences fuel efficiency
and CO2 emissions. Tires with higher rolling resistance lose
more energy in response to this deformation, thus using more fuel and
producing more CO2 emissions in operation, while tires with
lower rolling resistance lose less energy, and save more fuel and
CO2 emissions in operation. Tire design characteristics
(e.g., materials, construction, and tread design) influence durability,
traction (both wet and dry grip), vehicle handling, ride comfort, and
noise in addition to rolling resistance.
    The agencies explained that a typical Low Rolling Resistance (LRR)
tire's attributes, compared to a non-LRR tire, would include increased
tire inflation pressure; material changes; and tire construction with
less hysteresis, geometry changes (e.g., reduced height to width aspect
ratios), and reduction in sidewall and tread deflection. When a
manufacturer applies LRR tires to a vehicle, the manufacturer generally
also makes changes to the vehicle's suspension tuning and/or suspension
design in order to maintain vehicle handling and ride comfort.
    The agencies also explained that while LRR tires can be applied to
vehicles in all MD/HD classes, they may have special potential for
improving fuel efficiency and reducing CO2 emissions for
vocational vehicles. According to an energy audit conducted by Argonne
National Lab, tires are the second largest contributor to energy losses
of vocational vehicles, after engines.\123\ Given this finding, the
agencies considered the availability of LRR tires for vocational
applications by examining the population of tires available, and
concluded that there appeared to be few LRR tires for vocational
applications. The agencies suggested in the NPRM that this low number
of LRR tires for vocational vehicles could be due in part to the fact
that the competitive pressure to improve rolling resistance of
vocational vehicle tires has been less than in the line haul tire
market, given that line haul vehicles generally drive significantly
more miles and therefore have significantly higher operating costs for
fuel than vocational vehicles, and much greater incentive to improve
fuel consumption. The small number of LRR tires for vocational vehicles
may perhaps also be due in part to the fact that vocational vehicles
generally operate more frequently on secondary roads, gravel roads and
roads that have less frequent winter maintenance, which leads
vocational vehicle buyers to value tire traction and durability more
than rolling resistance. The agencies recognized that this provided an
opportunity to improve fuel consumption and GHG emissions by creating a
regulatory program that encourages improvements in tire rolling
resistance for both line haul and vocational vehicles. The agencies
proposed to base standards for all segments of HD vehicles on the use
of LRR tires. The agencies estimated that a 10 percent reduction in
average tire rolling resistance would be attainable between model years
2010 and 2014 based on the tire development achievements over the last
several years in the line haul truck market. This reduction in tire
rolling resistance would correlate to a two percent reduction in fuel
consumption as modeled by the GEM.\124\
---------------------------------------------------------------------------

    \123\ A Class 6 pick up and delivery truck at 50% load has tires
as the second largest contributor at speeds up to 35 mph, a typical
average speed of urban delivery vehicles. See Argonne National
Laboratory. ``Evaluation of Fuel Consumption Potential of Medium and
Heavy Duty Vehicles through Modeling and Simulation.'' October 2009.
Page 91.
    \124\ See 75 FR at 74241.
---------------------------------------------------------------------------

(i) Summary of Comments
    The agencies received many comments on the subject of tire rolling
resistance as applied to vocational vehicles. Comments included
suggestions for alternative test procedures; whether LRR tires should
be applied to certain types of vocational vehicles and whether certain
vehicles should be exempted from the vocational vehicle standards if
the standards are based on the ability to use LRR tires; the
appropriateness of the proposed standards; and compliance issues
(discussed below in Section II.D.2.b.
    Regarding whether LRR tires should be applied to certain types of
vocational vehicles, the agencies received many comments from
stakeholders, such as Daimler Trucks North America, Fire Apparatus
Manufacturers Association (FAMA), International Association of Fire
Chiefs, National Ready Mix, National Solid Wastes Management
Association (NSWMA), Spartan Motors, National Automobile Dealers
Association, among others. There were comments regarding applicability
of low rolling resistance tires to vocational vehicles based on LRR
tire availability, suitability of the tires for the applications, fuel
consumption and GHG emissions benefits and the appropriateness of
standards. Many of these commenters focused particularly on the whether
LRR tires would compromise the capability of emergency vehicles.
    Regarding whether LRR tires are available in the market for certain
vocational vehicles and whether the vocational vehicle standards were
therefore appropriate and feasible, both Ford and AAPC stated that the
proposed model-based requirement for Class 2b-8 vocational chassis
appeared to require tires with rolling resistance values of
approximately 8.0-8.1 kg/metric ton or better, and that limited data
available for smaller diameter tires, such as light-truck (LT) tires
used on many light heavy-duty trucks and vans, suggested that there
exist few if any choices for tires that would comply. Given this
concern about the availability of compliant tires, particularly in the
case of tires smaller than 22.5'', during the proposed regulatory time
frame, AAPC and Ford requested revisions to the requirement, or the
modeling method, to establish different standards for vehicles

that use different tire classes, with separate requirements for LT
tires, 19.5'' tires, and 22.5'' tires. AAPC argued that standards
should be set based on data collected on high volume in-use tires, and
that they should be set at a level that ensures the availability of
multiple compliant tires. CRR
(ii) Summary of Research Done Since the Notice of Proposed Rulemaking
    Since the NPRM, the agencies have conducted additional research on
tire rolling resistance for medium- and heavy-duty applications. This
research involved direct discussions with tire suppliers,\125\
assessment of the comments received, additional review of tire products
available, and a more thorough review of tire use in the field. In
addition, EPA has conducted tire rolling resistance testing to help
inform the final rulemaking.\126\
---------------------------------------------------------------------------

    \125\ Records of these communications, and additional
information submitted by the supplier companies and not CBI, are
available at Docket No. EPA-HQ-OAR-2010-0162.
    \126\ Bachman, Joseph. Memorandum to the Docket. Heavy-Duty Tire
Evaluation. July 2011. Docket EPA-HQ-OAR-2010-0162, Pages 3-6.
---------------------------------------------------------------------------

    The agencies discussed many aspects of low rolling resistance tire
technologies and their application to vocational vehicles with tire
suppliers since publication of the NPRM. Several tire suppliers
indicated to the agencies that low rolling resistance tires are
currently available for vocational applications that would enable
compliance with the proposed vocational vehicle standards, such as
delivery vehicles, refuse vehicles, and other vocations. However, these
conversations also made the agencies aware that availability of low
rolling resistance tires varies by supplier. Some suppliers stated they
focused their company resources on areas of the medium- and heavy-duty
vehicle spectrum where fleet operators would see the most fuel
efficiency benefits for the application of low rolling resistance
technologies; specifically the long-haul, on-highway applications that
drive many miles and use large amounts of fuel. These suppliers stated
that this choice was driven by the significant capital investment that
would be needed to improve tire rolling resistance across the
relatively large number of product offerings in the vocational vehicle
segment, based on the wide range of tire sizes, load ratings, and speed
ratings, compared to the much narrower range of offerings for long-haul
applications.\127\ Other suppliers stated that they have made conscious
efforts to reduce the rolling resistance of all of their medium- and
heavy-duty vehicle tire offerings, including vocational applications,
in an effort to become leaders in this technology.
---------------------------------------------------------------------------

    \127\ More tire types and sizes have been developed for
vocational vehicle applications than for long-haul applications. In
some cases, suppliers offer up to 17 different vocational tire
designs, and for each design there may be 8-10 different tire sizes.
In contrast, a line-haul application may have only 2-3 tire designs
with a fewer range of sizes.
---------------------------------------------------------------------------

    The agencies also discussed with tire suppliers the potential tire
attribute tradeoffs that may be associated with incorporating designs
that improve tire rolling resistance, given the driving patterns,
environmental conditions, and on-road and off-road surface conditions
that vocational vehicles are subjected to. Some vehicle manufacturer
commenters had suggested that changes in tire tread block design that
improve rolling resistance may adversely affect tire performance
characteristics such as traction, resistance to tearing, and resistance
to wear and damage from scrubbing on curbs and frequent tight radius
turns that are important to customers for vocational vehicle
performance. The suppliers agreed that providing tires unable to
withstand these conditions or meet the vehicle application needs would
adversely affect customer satisfaction and warranty expenses, and would
have detrimental financial effects to their businesses. One supplier
indicated that theoretically, tread-wear (tire life) could be
compromised if suppliers choose to reduce the initial tire tread depth
without any offsetting tire compound or design enhancements as the
means to achieve rolling resistance reductions. That supplier argued
that taking this approach could lead to more frequent tire replacements
or re-treading of existing tire carcasses, and that the agencies should
therefore take a total lifecycle view when evaluating the effects of
driving rolling resistance reductions. That supplier also indicated
that a correlation of a 20 percent reduction in rolling resistance
achieved through tread depth reduction could lead to a 30 percent
decrease in tread-life and 15 percent reduction in wet traction. The
agencies note that when they inquired about potential `safety' related
tradeoffs, such as traction (braking and handling) and tread wear when
applying low rolling resistance technologies, tire suppliers which
remain subject to safety standards regardless of this program,
consistently responded that they would not produce a tire that
compromises safety when fitted in its proper application.
    In addition to the supplier discussions and evaluation of comments
to the Notice of Proposed Rulemaking, EPA conducted a series of tire
rolling resistance tests on medium- and heavy-duty vocational vehicle
tires. The testing measured the CRR of tires representing 16 different
vehicle applications for Class 4-8 vocational vehicles. The testing
included approximately 5 samples each of both steer and drive tires for
each application. The tests were conducted by two independent tire test
labs, Standards Testing Lab (STL) and Smithers-Rapra (Smithers).
    Overall, a total of 156 medium- and heavy-duty tires\128\ were
included in this testing, which was comprised of 88 tires covering
various commercial vocational vehicle types, such as bucket trucks,
school buses, city delivery vehicles, city transit buses and refuse
haulers among others; 47 tires intended for application to tractors;
and 21 tires classified as light-truck (LT) tires intended for Class 4
vocational vehicles such as delivery vans. In addition, approximately
20 of the tires tested were exchanged between the labs to assess inter-
laboratory variability.
---------------------------------------------------------------------------

    \128\ After the agencies completed their analysis of these data,
the agencies received raw data on 43 additional tires. See Powell,
Greg. Memorandum to the Docket. Additional Tire Testing Results.
July 2011. Docket NHTSA-2010-0079. The agencies have not analyzed
these additional data, nor included them in the final report, and
the data therefore played no role in the agencies' determination of
an appropriate standard for vocational vehicles. The agencies will
analyze and consider these data, along with any future data received
through continued testing, as appropriate, in the next rulemaking
for the heavy duty sector.
---------------------------------------------------------------------------

    The test results for 88 commercial vocational vehicle tires (19.5''
and 22.5'' sizes) showed a test average CRR of 7.4 kg/metric ton, with
results ranging from 5.1 to 9.8. To comply with the proposed vocational
vehicle fuel consumption and GHG emissions standards using improved
tire rolling resistance as the compliance strategy, a manufacturer
would need to achieve an average tire CRR value of 8.1 kg/metric
ton.\129\ The measured average CRR of 7.4kg/metric ton is thus better
than the average value that would be needed to meet vocational vehicle
standards. Of those 173 tires tested, twenty tires had CRR values
exceeding 8.1 kg/metric ton, two were at 8.1 kg/metric ton, and sixty-
six tires were better than 8.1 kg/metric ton. Additional data analyses
examining the tire data by tire size to determine the range and
distribution of CRR values within each tire size showed each tire size
generally had tires ranging from approximately 6.0 to 8.5 kg/metric
ton, with a small number of tires in the 5.3-5.7 kg/metric ton range
and a small

number of tires in a range as high as 9.3-9.8 kg/ton. Review of the
data showed that for each tire size and vehicle type, the majority of
tires tested would enable compliance with vocational vehicle fuel
consumption and GHG emission standards.
---------------------------------------------------------------------------

    \129\ See 75 FR at 74244.
---------------------------------------------------------------------------

    The test results for the 47 tires intended for tractor application
showed an overall average of 6.9 kg/ton, the lowest overall average
rolling resistance of the different tire applications tested.\130\ This
is consistent with what the agencies heard through comments and
meetings with tire suppliers whose efforts have focused on tractor
applications, particularly for long-haul applications, which yield the
highest fuel efficiency benefits from LRR tire technology.
---------------------------------------------------------------------------

    \130\ The CRR values for these applications ranged from 5.4 to
9.2 kg/metric ton.
---------------------------------------------------------------------------

    Finally, the 21 LT tires intended for Class 4 vocational vehicles
were comprised of two sizes; LT225/75R16 and LT245/75R16 with 11 and 10
samples tested, respectively. Some auto manufacturers have indicated
that CRR values for tires fitted to these Class 4 vehicles typically
have a higher CRR values than tires found on commercial vocational
vehicles because of the smaller diameter wheel size and the ISO testing
protocol.\131\ The test data showed the average CRR for LT225/75R16
tires was 9.1 kg/metric ton and the average for LT245/75R16 tires was
8.6 kg/metric ton. The range for the LT225/75R16 tires spanned 7.4 to
11.0 \132\ and the range for the LT245/75R16 tires ranged from 6.6 to
9.8 kg/metric ton. Overall, the average for the tested LT tires was 8.9
kg/metric ton.
---------------------------------------------------------------------------

    \131\ See comments to docket EPA-HQ-OAR-2010-0162-1761; Ford
Motor Company
    \132\ The agency notes the highest CRR values recorded for LT
tires, of 11.0 and 10.9, were for two tires of the same size and
brand. The nearest recorded values to these two tires were 9.8;
substantially beyond the differences between other tires tested.
---------------------------------------------------------------------------

    Analysis of the EPA test data for all vocational vehicles,
including LT tires, shows the test average CRR is 7.7 kg/metric ton
with a standard deviation of 1.2 kg/metric ton. Review of the data thus
shows that for each tire size and vehicle type, there are many tires
available that would enable compliance with the proposed standards for
vocational vehicles and tractors except for LT tires for Class 4
vocational vehicles where test results show the majority of these tires
have CRR worse than 8.1 kg/metric ton.
    The agencies also reviewed the CRR data from the tires that were
tested at both the STL and Smithers laboratories to assess inter-
laboratory and test machine variability. The agencies conducted
statistical analysis of the data to gain better understanding of lab-
to-lab correlation and developed an adjustment factor for data measured
at each of the test labs. When applied, this correction factor showed
that for 77 of the 80 tires tested, the difference between the original
CRR and a value corrected CRR was 0.01 kg/metric ton. The values for
the remaining three tires were 0.03 kg/metric ton, 0.05 kg/metric ton
and 0.07 kg/metric ton. Based on these results, the agencies believe
the lab-to-lab variation for the STL and Smithers laboratories would
have very small effect on measured CRR values. Further, in analyzing
the data, the agencies considered both measurement variability and the
value of the measurements relative to proposed standards. The agencies
concluded that although laboratory-to-laboratory and test machine-to-
test machine measurement variability exists, the level observed is not
excessive relative to the distribution of absolute measured CRR
performance values and relative to the proposed standards. Based on
this, the agencies concluded that the test protocol is reasonable for
this program, but are making some revisions to the vehicle standards.
    The agencies also conducted a winter traction test of 28 tires to
evaluate the impact of low rolling resistance designs on winter
traction. The results of the study indicate that there was no
statistical relationship between rolling resistance and snow
traction.\133\
---------------------------------------------------------------------------

    \133\ Bachman, Joseph. Memorandum to Docket. Heavy-Duty Tire
Evaluation. Docket EPA-HQ-OAR-2010-0162. Pages 3-6.
---------------------------------------------------------------------------

(iii) Summary of Final Rules
    For vocational vehicles, the agencies intend to keep rolling
resistance as an input to the GEM but with modifications to the
proposed targets as a result of the testing completed by EPA since the
NPRM and information from tire suppliers. The agencies continue to
believe that LRR tires, which are an available, cost-effective, and
appropriate technology with demonstrated fuel efficiency and GHG
reduction benefits, are reasonable for all on-highway vehicles.
    The agencies acknowledge there can be tradeoffs when designing a
tire for reduced rolling resistance. These tradeoffs can include
characteristics such as wear resistance, cost and scuff resistance.
However, the agencies have continued to review this issue and do not
believe that LRR tires as specified in the rules present safety issues.
The agencies continue to believe that LRR tires, which are an
available, cost-effective, and appropriate technology with demonstrated
fuel efficiency and GHG reduction benefits, are reasonable for all on-
highway vehicles. The final program also provides exemptions for
vehicles meeting ``low-speed'' or ``off-road'' criteria, including
application of speed restricted tires. Vocational vehicles that have
speed restricted tires in order to accommodate particular applications
may be exempted from the program under the off-road or low-speed
exemption, described in greater detail below in Section
II.D.(1)(a)(iv).
    As just noted, the agencies conducted independent testing of
current tires available to assist confirming the finalized rolling
resistance standards. The tire test samples were selected from those
currently available on the market and therefore have no known safety
issues and meet all current requirements to allow availability in
commerce; including wear, scuff resistance, braking, traction under wet
or icy conditions, and other requirements. These tires included a wide
array of sizes and designs intended for most all vocational
applications, including those used for school buses, refuse haulers,
emergency vehicles, concrete mixers, and recreational vehicles. As the
test results revealed, there are a significant number of tires
available that meet or do better than the rolling resistance targets
for vocational vehicles; both light-truck (with an adjustment factor
described later in this preamble section) and non-LT tire types, while
meeting all applicable safety standards.
    The agencies also recognize the extreme conditions fire apparatus
equipment must navigate to enable firefighters to perform their duties.
As described below, the final rules contain provisions to allow for
exemption of specific off-road capable vocational vehicles from the
fuel efficiency and greenhouse gas standards. Included in the exemption
criteria are provisions for vehicles equipped with specific tire types
that would be fit to a vehicle to meet extreme demands, including those
vehicles designed for off-road capability.
    As follow-up to the final rules and in support for development of a
separate FMVSS rule, NHTSA plans to conduct additional performance-
focused testing (beyond rolling resistance) for medium- and heavy-duty
trucks. This testing is targeted for completion toward the end of this
year. The agencies will review these performance data when available,
in concert with any subsequent proposed rulemakings regarding fuel
consumption and GHG emissions

standards for medium- and heavy-duty vehicles.
    For vocational vehicles, the rolling resistance of each tire will
be measured using the ISO 28850 test method for drive tires and steer
tires planned for fitment to the vehicle being certified. Once the test
CRR values are obtained, a manufacturer will input the CRR values for
the drive and steer tires separately into the GEM where, for vocational
vehicles, the vehicle load is distributed equally over the steer and
drive tires. Once entered, the amount of GHG reduction attributed to
tire rolling resistance will be incorporated into the overall vehicle
compliance value. The following table provides the revised target CRR
values for vocational vehicles for 2014 and 2017 model years that are
used to determine the vehicle standards.

    Table II-14--Vocational Vehicle--Target CRR Values for GEM Input
------------------------------------------------------------------------
                                        2014 MY             2017 MY
------------------------------------------------------------------------
Tire Rolling Resistance (kg/      7.7 kg/metric ton.  7.7 kg/metric ton
 metric ton).
------------------------------------------------------------------------

    These target values are being revised based on the significant
availability of tires for vocational vehicles applications which have
performance better than the originally proposed 8.1 kg/metric ton
target. As just discussed, 63 of the 88 tires tested for vocational
applications had CRR values better than the proposed target. The tires
tested covered fitment to a wide range of vocational vehicle types and
classes; thus agencies believe the original target value of 8.1 kg/
metric ton was possibly too lenient after reviewing the testing data.
Therefore, the agencies believe it is appropriate to reduce the
proposed vehicle standard based on performance of a CRR target value of
7.7 kg/metric ton for non-LT tire type. As discussed previously, this
value is the test average of all vocational tires tested (including LT)
which takes a conservative approach over setting a target based on the
average of only the non-LT vocational tires tested. For LT tires, based
on both the test data and the comments from AAPC and Ford Motor
Company, the agencies recognize the need to provide an adjustment. In
lieu of having two sets of Light Heavy-Duty vocational vehicle
standards, the agencies are finalizing an adjustment factor which
applies to the CRR test results for LT tires. The agencies developed an
adjustment factor dividing the overall vocational test average CRR of
7.7 by the LT vocational average of 8.9. This yields an adjustment
factor of 0.87. For LT vocational vehicle tires, the measured CRR
values will be multiplied by the 0.87 adjustment factor before entering
the values in the GEM for compliance.
    Based on the tire rolling resistance inputs noted above, EPA is
finalizing the following CO2 standards for the 2014 model
year for the Class 2b through Class 8 vocational vehicle chassis, as
shown in Table II-15. Similarly, NHTSA is finalizing the following fuel
consumption standards for the 2016 model year, with voluntary standards
beginning in the 2014 model year. For the EPA GHG program, the standard
applies throughout the useful life of the vehicle. The agencies note
that both the baseline performance and standards derived for the final
rules slightly differ from the values derived for the NPRM. The first