----------------------------------------------------------------------------------------------------------------
                                      100% improved axle lubrication: 0.5%
----------------------------------------------------------------------------------------------------------------
                                   100% Steer Tires with CRR 6.7 kg/metric ton
----------------------------------------------------------------------------------------------------------------
                                   100% Drive Tires with CRR 7.1 kg/metric ton
----------------------------------------------------------------------------------------------------------------
                                             Weight Reduction 200 lb
----------------------------------------------------------------------------------------------------------------
Note:
\a\ SI engines were not simulated in GEM.

                       Table V-15--GEM Inputs for Benchmarked MY 2027 Vocational Vehicles
----------------------------------------------------------------------------------------------------------------
              Class 2b-5                             Class 6-7                              Class 8
----------------------------------------------------------------------------------------------------------------
                Multi-                                 Multi-                               Multi-
   Urban       purpose      Regional      Urban       purpose      Regional      Urban      purpose    Regional
----------------------------------------------------------------------------------------------------------------
                                                  Transmission
----------------------------------------------------------------------------------------------------------------
                  100% Deep Transmission Integration for 7% Urban, 6% Multipurpose, 5% Regional
----------------------------------------------------------------------------------------------------------------
     5s AT        5s AT        5s AT        5s AT        5s AT        5s AT       5s AT       5s AT     10s AMT
----------------------------------------------------------------------------------------------------------------

                                                  CI Engine \a\
----------------------------------------------------------------------------------------------------------------
      2027 MY 7L, 22027 MY 7L, 270 hp Engine
                2027 MY 11L, 345 hp    2027 MY 15L
                      Engine                455hp
                                           Engine
----------------------------------------------------------------------------------------------------------------
                                        100% Idle Reduction = Stop-Start
----------------------------------------------------------------------------------------------------------------
                                   100% Steer Tires with CRR 6.4 kg/metric ton
----------------------------------------------------------------------------------------------------------------
                                   100% Drive Tires with CRR 7.0 kg/metric ton
----------------------------------------------------------------------------------------------------------------
                                             Weight Reduction 200 lb
----------------------------------------------------------------------------------------------------------------
Note:
\a\ SI engines were not simulated in GEM.

    Next we identified the best performing baseline vehicle in each
weight class group (one for HHD, one for MHD and one for LHD) and
normalized the baseline GEM results to the performance of that vehicle.
A complete description of this normalization process is found in the
draft RIA Chapter 2. We then applied our actual projected technology
adoption rates, including hybrid powertrains and stop-start idle
reduction, to normalized-benchmarked vehicles in each of the nine
subcategories. The proposed standards then were calculated by
multiplying the normalized baseline vehicle GEM result by an average
percent improvement for each weight class group. For example, the GEM
results from applying the projected technology mix for MY 2021 MHD CI
vocational vehicles were a 5 percent improvement in the Regional MHD
subcategory, 7 percent improvement in the MHD Multipurpose subcategory,
and 8 percent improvement in the MHD Urban subcategory. To achieve
standards with equivalent stringency, we multiplied each normalized
baseline vehicle's GEM performance by the numerical average of those
simulated improvements, 6.6 percent. Without comparable stringency
across the subcategories, manufacturers could have an incentive to
select a subcategory strategically to have a less stringent standard,
rather than to certify vehicles in the subcategory that best matches
the vehicles' expected use patterns. By setting the standards at the
same percent reduction from each weight class group of normalized-
benchmarked vehicles, we would expect to minimize any incentive for a
manufacturer to certify a vocational vehicle in an inappropriate
subcategory.
    We request comment on using this approach to normalize the
standards. Commenters are encouraged to address both the approach in
general and the specific technology assumed for the benchmark vehicles.
    We are aware that in this approach, some of the projected
technology packages would not provide a direct path to compliance for
manufacturers, such as in the example above of the MHD Regional
vehicle. Using the technologies adopted at projected rates, it would
fall short of the standard by 1.5 percent. The agencies believe that
the Phase 2 program has enough regulatory flexibility (averaging,
banking, and trading provisions in particular) to enable such a vehicle
to be certified.
    In the package descriptions that follow, individual technology
costs are not presented, rather these can be found in the draft RIA
Chapter 2.9 and 2.12. Section V. C. (2) (d) includes the costs
estimated for packages of technologies the agencies project would
enable vocational vehicles to meet the proposed Phase 2 standards.
(i) Transmission Packages
    The agencies project that 30 percent of vocational vehicles would
have one or more of the transmission technologies identified above in
this section applied by MY 2021, increasing to nearly 60 percent by MY
2024 and over 80 percent by MY 2027. Most of this increase is due to a
projected increase in adoption of technologies that represent deep
driveline integration. The agencies project an adoption rate of 15
percent in MY 2021 and 30 percent in MY 2024 for manufacturers using
the powertrain test to be recognized for non-hardware upgrades such as
gear efficiencies, shift strategies, and torque converter lockups, as
well as other technologies that enable driveline optimization. Due to
the relatively high efficiency gains available from driveline
optimization for relatively low costs, the agencies are projecting a 70
percent application rate of driveline optimization by MY 2027 across
all subcategories. We do not have information about the extent to which
integration may be deterred by barriers to information-sharing between
component suppliers. Therefore we are projecting that major
manufacturers would work to overcome these barriers, integrate and
optimize their drivelines, and use the powertrain test on all eligible
configurations, while smaller manufacturers may not adopt these
technologies at all, or not to a degree that they would find value in
this optional test procedure.
    For the technology of adding two gears, we are predicating the
proposed MY 2021 standard on a five percent adoption rate, except zero
in the HHD Regional subcategory, which is modeled with a 10-speed
transmission. This adoption rate is projected to essentially remain at
this level throughout the program, with an increase to ten percent only
for two subcategories (Regional LHD and MHD) in MY 2027. This is
because the manufacturers most likely to develop 8-speed transmissions
are those that are also developing transmissions for HD pickups and
vans, and the GEM-certified vocational market share among those
manufacturers is relatively small.
    The HHD Regional subcategory is the only one where we assume a
manual transmission in the baseline configuration. For these vehicles,
the agencies project upgrades to electronic transmissions such as
either AMT, DCT, or automatic, at collective adoption rates of 51
percent in MY 2021, 68 percent in MY 2024, and five percent in MY 2027.
The decrease in MY 2027 reflects a projection that a greater number of
deeply integrated HHD powertrains would be used by MY 2027 (one
consequence being that fewer HHD

powertrains would be directly simulated in GEM in that year). The
larger numbers in the phase-in years reflect powertrains that have been
automated or electrified but not deeply integrated. The agencies have
been careful to account for the cost of both electrifying and deeply
integrating the MY 2027 powertrains. In draft RIA Chapter 11, the
technology adoption rates for the HHD Regional subcategory presented in
Table 11-42, Table 11-45, and Table 11-48 account for the assumption
that a manual transmission cannot be deeply integrated, so there must
also be an automation upgrade. These tables are inputs to the agencies'
cost analysis, thus the costs of both upgrading and integrating HHD
powertrains are included. The adoption rates of the upgraded but not
integrated transmission architectures represent a projection of three
percent of all vocational vehicles in MY 2021 and four percent in MY
2024. This is based on an estimate that seven percent of the vocational
vehicles would be in the HHD Regional subcategory. For more information
about the assumptions that were made about the populations of vehicles
in different subcategories, see the agencies' inventory estimates in
draft RIA Chapter 5.
    In the eight subcategories in which automatic transmissions are the
base technology, the agencies project that five percent would upgrade
to a dual clutch transmission in MY 2021. This projection increases to
15 percent in MY 2024 and decreases in MY 2027 to ten percent for two
subcategories (Regional LHD and MHD) and five percent for the remaining
6 subcategories. The low projected adoption rates of DCT reflect the
fact that this is a relatively new technology for the heavy-duty
sector, and it is likely that broader market acceptance would be
achieved once fleets have gained experience with the technology.
Similar to the pattern described for the HHD Regional subcategory, the
decrease in MY 2027 reflects a projection of greater use of deeply
integrated powertrains.
    In setting the proposed standard stringency, we have projected that
hybrids on vehicles certified in the Multipurpose subcategories would
achieve on average 22 percent improvement, and those in the Urban
subcategories would see a 25 percent improvement. We have also
projected zero hybrid adoption rate by vehicles in the Regional
subcategories, expecting that the benefit of hybrids for those vehicles
would be too low to merit use of that type of technology. However,
there is no fixed hybrid value assigned in GEM and the actual
improvement over the applicable test cycle would be determined by
powertrain testing. By the full implementation year of MY 2027, the
agencies are projecting an overall vocational vehicle adoption rate of
ten percent hybrids, which we estimate would be 18 percent of vehicles
certified in the Multi-Purpose and Urban subcategories. We are
projecting a low adoption rate in the early years of the Phase 2
program, just four percent in these subcategories in MY 2021, and seven
percent in MY 2024 for vehicles certified in the Multi-Purpose and
Urban subcategories. Based on our assumptions about the populations of
vehicles in different subcategories, these hybrid adoption rates are
about two percent overall in MY 2021 and four percent overall in MY
2024.
    Considering the combination of the above technologies and adoption
rates, we project the CO2 and fuel efficiency improvements
for all transmission upgrades to be approximately seven percent on a
fleet basis by MY 2027. One subcategory in which we are projecting a
very large advanced transmission adoption rate is the HHD Regional
subcategory, in which we are projecting 75 percent of the transmissions
would be either automated or automatic (upgraded from a manual) with 70
percent of those also being deeply integrated by MY 2027. By
comparison, the agencies are projecting that HHD day cab tractors would
have 90 percent adoption of automated or automatic transmissions by MY
2027. Although we are not prepared to predict what fraction of these
would be upgraded in the absence of Phase 2, the draft RIA Chapter 2.9
explains why the agencies are confident that durable transmissions will
be widely available in the Phase 2 time frame to support manufacture of
HHD vocational vehicles.
    If the above technologies do not reach the expected level of market
adoption, the vocational vehicle Phase 2 program has several other
technology options that manufacturers could choose to meet the proposed
standards.
(ii) Axle Packages
    The agencies project that 75 percent of vocational vehicles in all
subcategories would adopt advanced axle lubricant formulations in all
implementation years of the Phase 2 program. Fuel efficient lubricant
formulations are widespread across the heavy-duty market, though
advanced synthetic formulations are currently less popular.\314\ Axle
lubricants with improved viscosity and efficiency-enhancing performance
are projected to be widely adopted by manufacturers in the time frame
of Phase 2. Such formulations are commercially available and the
agencies see no reason why they could not be feasible for most
vehicles. Nonetheless, we have refrained from projecting full adoption
of this technology. The agencies do not have specific information
regarding reasons why axle manufacturers may specify a specific type of
lubricant over another, and whether advanced lubricant formulations may
not be recommended in all cases. The agencies request comment on
information regarding any vocational vehicle applications for which use
of advanced lubricants would not be feasible.
---------------------------------------------------------------------------

    \314\ Based on conversations with axle suppliers.
---------------------------------------------------------------------------

    The agencies estimate that 45 percent of HHD Regional vocational
vehicles would adopt either full time or part time 6x2 axle technology
in MY 2021. This technology is most likely to be applied to Class 8
vocational vehicles (with 2 rear axles) that are designed for frequent
highway trips. The agencies project a slightly higher adoption rate of
60 percent combined for both full and part time 6x2 axle technologies
in MY 2024 and MY 2027. Based on our estimates of vehicle populations,
this is about four percent of all vocational vehicles.
(iii) Tire Packages
    The agencies estimate that the per-vehicle average level of rolling
resistance from vocational vehicle tires could be reduced by 11 percent
by full implementation of the Phase 2 program in MY 2027, based on the
tire development achievements expected over the next decade. This is
estimated by weighting the projected improvements of steer tires and
drive tires using an assumed axle load distribution of 30 percent on
the steer tires and 70 percent on the drive tires, as explained in the
draft RIA Chapter 2.9. The projected adoption rates and expected
improvements in CRR are presented in Table V-16. By applying the
assumed axle load distribution, the average vehicle CRR improvements
projected for the proposed MY 2021 standards would be four percent,
which we project would achieve up to one percent reduction in fuel use
and CO2 emissions, depending on the vehicle subcategory.
Using that same method, the agencies estimate the average vehicle CRR
in MY 2024 would be seven percent, yielding reductions in fuel use and
CO2 emissions of between one and two percent, depending on
the vehicle subcategory.
    The agencies understand that the vocational vehicle segment has
access to

a large variety of tires, including some that are designed for
tractors, some that are designed for HD pickups and vans, and some with
multiple use designations. In spite of the likely availability of LRR
tires during the Phase 2 program, the projected adoption rates are
intended to be conservative. The agencies believe that these tire
packages recognize the variety of tire purposes and performance levels
in the vocational vehicle market, and maintain choices for
manufacturers to use the most efficient tires (i.e. those with least
rolling resistance) only where it makes sense given these vehicles'
differing purposes and applications.

                                  Table V-16--Projected LRR Tire Adoption Rates
----------------------------------------------------------------------------------------------------------------
                                          Level of rolling         MY 2021          MY 2024          MY 2027
            Tire position                    resistance         adoption rate    adoption rate    adoption rate
----------------------------------------------------------------------------------------------------------------
Drive...............................  Baseline CRR (7.7).....               50               20               10
Steer...............................  Baseline CRR (7.7).....               20               10                0
Drive...............................  5% Lower CRR (7.3).....               50               50               25
Steer...............................  10% Lower CRR (6.9)....               80               30               20
Drive...............................  10% Lower CRR (6.9)....                0               30               50
Steer...............................  15% Lower CRR (6.5)....                0               60               30
Drive...............................  15% Lower CRR (6.5)....                0                0               15
Steer...............................  20% Lower CRR (6.2)....                0                0               50
Drive...............................  Average Improvement in                3%               6%               9%
                                       CRR.
Steer...............................  Average Improvement in                8%              12%              17%
                                       CRR.
----------------------------------------------------------------------------------------------------------------

    For comparison purposes, the reader may note that these levels of
tire CRR generally correspond with levels of tire CRR projected for
tractors built for the Phase 1 standards. For example, the baseline
level CRR for vocational tires is very similar to the baseline tractor
steer tire CRR. Vocational vehicle tires with 10 percent better CRR
have a similar CRR level as tractor tires of Drive Level 1. Vocational
vehicle tires with 15 percent better CRR have a similar CRR level as
tractor tires of Steer Level 1. Vocational vehicle tires with 20
percent better CRR have a similar CRR level as tractor tires of Drive
Level 2, as described in Section III.D.2.
(iv) Idle Reduction Packages
    In this proposal, we are projecting a progression of idle reduction
technology development that begins with 70 percent adoption rate of
neutral idle for the MY 2021 standards, which by MY 2027 is replaced by
a 70 percent adoption rate of stop-start idle reduction technology.
Although it is possible that a vehicle could have both neutral idle and
stop-start, we are only considering emissions reductions for vehicles
with one or the other of these technologies. Also, as the program
phases in, we do not see a reduction in the projected adoption rate of
neutral idle to be a concern in terms of stranded investment, because
it is a very low cost technology that could be an enabler for stop-
start systems in some cases.
    We are not projecting any adoption of neutral idle for the HHD
Regional subcategory, because any vehicle with a manual transmission
must shift to neutral when stopped to avoid stalling the engine, so
that vehicles in the HHD Regional subcategory would already essentially
be idling in neutral and no additional technology would be needed to
achieve this. A similar case can be made for any vocational vehicle
with an automated manual transmission, since these share inherently
similar architectures with manuals. The agencies are not projecting an
adoption rate of 85 percent neutral idle until MY 2024, because it may
take some additional development time to apply this technology to high-
torque automatic transmissions designed for the largest vocational
vehicles. Based on stakeholder input, the designs needed to avoid an
uncomfortable re-engagement bump when returning to drive from neutral
may require some engineering development time as well as some work to
enable two-way communication between engines and transmissions.
    We are projecting a five percent adoption rate of stop-start in the
six MHD and LHD subcategories for MY 2021 and zero for the HHD
vehicles, because this technology is still developing for vocational
vehicles and is most likely to be feasible in the early years of Phase
2 for vehicles with lower power demands and lower engine inertia.
Stopping a heavy-duty engine is not challenging. The real challenge is
designing a robust system that can deliver multiple smooth restarts
daily without loss of function while the engine is off. Many current
light-duty products offer this feature, and some heavy-duty
manufacturers are exploring this.\315\ The agencies are projecting an
adoption rate of 15 percent stop-start across all subcategories in the
intermediate year of MY 2024. The agencies are projecting this
technology to have a relatively high adoption rate (70 percent as
stated above) by MY 2027 because we see it being technically feasible
on the majority of vocational vehicles, and especially effective on
those with the most time at idle in their workday operation. Although
we are not prepared to predict what fraction of vehicles would adopt
stop-start in the absence of Phase 2, the draft RIA Chapter 2.9
explains why the agencies are confident that this technology, which is
on the entry-level side of the hybrid and electrification spectrum,
will be widely available in the Phase 2 time frame.
---------------------------------------------------------------------------

    \315\ See Ford announcement December 2013, https://
media.ford.com/content/fordmedia/fna/us/en/news/2013/12/12/70-
percent-of-ford-lineup-to-have-auto-start-stop-by-2017--fuel-.html.
See also Allison-Cummins announcement July 2014, http://www.oemoffhighway.com/press_release/12000208/allison-stop-start?utm_source=OOH+Industry+News+eNL&utm_medium=email&utm_campaign=RCL140723006.
---------------------------------------------------------------------------

    Based on these projected adoption rates and the effectiveness
values described above in this section, we expect overall GHG and fuel
consumption reductions from workday idle on vocational vehicles to be
approximately three percent in MY 2027.
(v) Weight Reduction Packages
    As described in the draft RIA Chapter 2.12, weight reduction is a
relatively costly technology, at approximately $3 to $4 per pound for a
200-lb package. Even so, for vehicles in service classes where dense,
heavy loads are frequently carried, weight reduction can translate
directly to additional payload. The agencies project weight reduction
would most likely be used for vocational vehicles in the refuse and
construction service classes, as well as some regional delivery
vehicles. The agencies are

predicating the proposed standards on an adoption rate of five to eight
percent, depending on the subcategory, in MY 2027, with slightly lower
adoption rates in MY 2021 and MY 2024.
    For this technology package, NHTSA and EPA project manufacturers
would use material substitution in the amount of 200 lbs. An example of
how this weight could be reduced would be a complete set of aluminum
wheels for a Class 8 vocational vehicle, or an aluminum transmission
case plus high strength steel wheels, frame rails, and suspension
brackets on a MHD or LHD vocational vehicle. The agencies have limited
information about how popular the use of aluminum components is in the
vocational vehicle sector. We request comments with information on
whether any lightweight vocational vehicle components are in such
widespread use that we should exclude them from the list of components
for which a GEM improvement value would be available.
(c) GEM Inputs for Derivation of Proposed Vocational Vehicle Standards
    To derive the stringency of the proposed vocational vehicle
standards, the agencies developed a suite of fuel consumption maps for
use with the GEM: One set of maps that represent engines meeting the
proposed MY 2021 vocational diesel engine standards, a second set of
maps representing engines meeting the proposed MY 2024 vocational
diesel engine standards, and a third set of maps representing engines
meeting the proposed MY 2027 vocational diesel engine standards.\316\
By incorporating the engine technology packages projected to be adopted
to meet the proposed Phase 2 vocational CI engine standards, the
agencies employed GEM engine models in deriving the stringency of the
proposed Phase 2 CI-powered vocational vehicle standards. As noted
above, because the agencies did not have enough information to develop
a robust GEM-based gasoline engine fuel map, the stringency of the
proposed SI-powered vocational vehicle standards is derived as an
adjustment from the CI-powered vocational vehicle standards. See the
draft RIA Chapter 2.9 for more details about this adjustment process.
---------------------------------------------------------------------------

    \316\ See Section II.D.2 of this preamble for the derivation of
the engine standards.
---------------------------------------------------------------------------

    Depending on the particular technology, either the effectiveness
was assigned by the agencies using an accepted average value, or the
GEM tool was used to assess the proposed technology effectiveness, as
discussed above. The agencies derived a scenario vehicle for each
subcategory using the adoption rate and assigned or modeled improvement
values of transmission, axle, and idle reduction technologies. For
example, the MY 2021 CRR values for each subcategory scenario case were
derived as follows: For steer tires--20 percent times 7.7 plus 80
percent times 6.9 yields an average CRR of 7.1 kg/metric ton; and for
drive tires--50 percent times 7.7 plus 50 percent times 7.3 yields an
average CRR of 7.5 kg/metric ton. Similar calculations were done for
weight reduction, transmission improvements, and axle improvements. The
set of tire CRR, idle reduction, weight reduction, engine and
transmission input parameters that was modeled in GEM in support of the
proposed MY 2021 vocational vehicle standards is shown in Table V-17.
The agencies derived the level of the proposed MY 2024 standards by
using the tire, weight reduction, engine and transmission GEM inputs
shown in Table V-18, below. The agencies derived the level of the
proposed MY 2027 standards by using the tire, weight reduction, engine
and transmission GEM inputs shown in Table V-19, below. As post-
processing, the respective adoption rates and assigned improvement
values of transmission, axle, and idle reduction technologies were
calculated for each subcategory.
    The agencies have not directly transferred the GEM results from
these inputs as the proposed standards. Rather, the proposed standards
are the result of the normalizing and benchmarking analysis described
above. The proposed standards are presented in Table V-4 through Table
V-9. Additional detail is provided in the RIA Chapter 2.9.

               Table V-17--GEM Inputs Used To Derive Proposed MY 2021 Vocational Vehicle Standards
----------------------------------------------------------------------------------------------------------------
              Class 2b-5                             Class 6-7                              Class 8
----------------------------------------------------------------------------------------------------------------
                Multi-                                 Multi-                               Multi-
   Urban       purpose      Regional      Urban       purpose      Regional      Urban      purpose    Regional
----------------------------------------------------------------------------------------------------------------
                                                  CI Engine \a\
----------------------------------------------------------------------------------------------------------------
      2021 MY 7L, 200 hp E2021 MY 7L,
                   2021 MY 11L,        2021 MY 15L
            200 hp Engine270 hp Engine
                   345 hp Engine            455hp
                                           Engine
----------------------------------------------------------------------------------------------------------------
                                        Transmission (improvement factor)
----------------------------------------------------------------------------------------------------------------
     0.023        0.021        0.008        0.023        0.021        0.009       0.023       0.022       0.022
----------------------------------------------------------------------------------------------------------------
                                            Axle (improvement factor)
----------------------------------------------------------------------------------------------------------------
     0.004        0.004        0.004        0.004        0.004        0.004       0.004       0.004       0.012
----------------------------------------------------------------------------------------------------------------
                                           Stop-Start (adoption rate)
----------------------------------------------------------------------------------------------------------------
        5%           5%           5%           5%           5%           5%          0%          0%          0%
----------------------------------------------------------------------------------------------------------------
                                          Neutral Idle (adoption rate)
----------------------------------------------------------------------------------------------------------------
       70%          70%          70%          70%          70%          70%         70%         70%          0%
----------------------------------------------------------------------------------------------------------------
                                         Steer Tires (CRR kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       7.1          7.1          7.1          7.1          7.1          7.1         7.1         7.1         7.1
----------------------------------------------------------------------------------------------------------------

                                         Drive Tires (CRR kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       7.5          7.5          7.5          7.5          7.5          7.5         7.5         7.5         7.5
----------------------------------------------------------------------------------------------------------------
                                              Weight Reduction (lb)
----------------------------------------------------------------------------------------------------------------
         8            8           14            8            8           12           8           8          10
----------------------------------------------------------------------------------------------------------------
Note:
\a\ SI engines were not simulated in GEM, rather a gas/diesel adjustment factor was applied to the results.

               Table V-18--GEM Inputs Used To Derive Proposed MY 2024 Vocational Vehicle Standards
----------------------------------------------------------------------------------------------------------------
              Class 2b-5                             Class 6-7                              Class 8
----------------------------------------------------------------------------------------------------------------
                Multi-                                 Multi-                               Multi-
   Urban       purpose      Regional      Urban       purpose      Regional      Urban      purpose    Regional
----------------------------------------------------------------------------------------------------------------
                                                  CI Engine\a\
----------------------------------------------------------------------------------------------------------------
             2024 MY 7L,  2024 MY 11L,
                   2024 MY 15L,        2024 MY 15L
            270 hp Engine345 hp Engine
                   455hp Engine             455hp
                                           Engine
----------------------------------------------------------------------------------------------------------------
                                        Transmission (improvement factor)
----------------------------------------------------------------------------------------------------------------
     0.045         0.04        0.017        0.045        0.041        0.018       0.045       0.042       0.035
----------------------------------------------------------------------------------------------------------------
                                            Axle (improvement factor)
----------------------------------------------------------------------------------------------------------------
     0.004        0.004        0.004        0.004        0.004        0.004       0.004       0.004       0.014
----------------------------------------------------------------------------------------------------------------
                                           Stop-Start (adoption rate)
----------------------------------------------------------------------------------------------------------------
       15%          15%          15%          15%          15%          15%         15%         15%         15%
----------------------------------------------------------------------------------------------------------------
                                          Neutral Idle (adoption rate)
----------------------------------------------------------------------------------------------------------------
       85%          85%          85%          85%          85%          85%         85%         85%          0%
----------------------------------------------------------------------------------------------------------------
                                         Steer Tires (CRR kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       6.8          6.8          6.8          6.8          6.8          6.8         6.8         6.8         6.8
----------------------------------------------------------------------------------------------------------------
                                         Drive Tires (CRR kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       7.3          7.3          7.3          7.3          7.3          7.3         7.3         7.3         7.3
----------------------------------------------------------------------------------------------------------------
                                              Weight Reduction (lb)
----------------------------------------------------------------------------------------------------------------
         8            8           14            8            8           12           8           8          10
----------------------------------------------------------------------------------------------------------------
Note:
\a\ SI engines were not simulated in GEM, rather a gas/diesel adjustment factor was applied to the results.

               Table V-19--GEM Inputs Used To Derive Proposed MY 2027 Vocational Vehicle Standards
----------------------------------------------------------------------------------------------------------------
              Class 2b-5                             Class 6-7                              Class 8
----------------------------------------------------------------------------------------------------------------
                Multi-                                 Multi-                               Multi-
   Urban       purpose      Regional      Urban       purpose      Regional      Urban      purpose    Regional
----------------------------------------------------------------------------------------------------------------
                                                  CI Engine \a\
----------------------------------------------------------------------------------------------------------------
             2027 MY 7L,  2027 MY 7L,
                   2027 MY 11L,        2027 MY 15L
            200 hp Engine270 hp Engine
                   345 hp Engine            455hp
                                           Engine
----------------------------------------------------------------------------------------------------------------
                                        Transmission (improvement factor)
----------------------------------------------------------------------------------------------------------------
     0.096        0.085        0.034        0.096        0.088        0.037       0.097       0.089       0.036
----------------------------------------------------------------------------------------------------------------
                                            Axle (improvement factor)
----------------------------------------------------------------------------------------------------------------
     0.004        0.004        0.004        0.004        0.004        0.004       0.004       0.004       0.014
----------------------------------------------------------------------------------------------------------------

                                           Stop-Start (adoption rate)
----------------------------------------------------------------------------------------------------------------
       75%          70%          70%          75%          70%          70%         70%         70%         70%
----------------------------------------------------------------------------------------------------------------
                                          Neutral Idle (adoption rate)
----------------------------------------------------------------------------------------------------------------
       25%          30%          30%          25%          30%          30%         30%         30%          0%
----------------------------------------------------------------------------------------------------------------
                                         Steer Tires (CRR kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       6.4          6.4          6.4          6.4          6.4          6.4         6.4         6.4         6.4
----------------------------------------------------------------------------------------------------------------
                                         Drive Tires (CRR kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       7.0          7.0          7.0          7.0          7.0          7.0         7.0         7.0         7.0
----------------------------------------------------------------------------------------------------------------
                                              Weight Reduction (lb)
----------------------------------------------------------------------------------------------------------------
        10           10           16           10           10           14          10          10          12
----------------------------------------------------------------------------------------------------------------
Note:
\a\ SI engines were not simulated in GEM, rather a gas/diesel adjustment factor was applied to the results.

(d) Technology Package Costs
    The agencies have estimated the costs of the technologies that
could be used to comply with the proposed standards. The estimated
costs are shown in Table V-20 for MY2021, in Table V-21 for MY2024, and
Table V-22 for MY 2027. Fleet average costs are shown for light, medium
and heavy HD vocational vehicles in each duty-cycle-based subcategory--
Urban, Multi-Purpose, and Regional. As shown in Table V-20, in MY 2021
these range from approximately $600 for MHD and LHD Regional vehicles,
up to $3,400 for HHD Regional vehicles. Those two lower-cost packages
reflect zero hybrids, and the higher-cost package reflects significant
adoption of automated transmissions. In the draft RIA Chapter 2.13.2,
the agencies present vocational vehicle technology package costs
differentiated by MOVES vehicle type. For example, intercity buses are
estimated to have an average package cost of $2,900 and gasoline motor
homes are estimated to have an average package cost of $450 in MY 2021.
These costs do not indicate the per-vehicle cost that may be incurred
for any individual technology. For more specific information about the
agencies' estimates of per-vehicle costs, please see the draft RIA
Chapter 2.12. For example, Chapter 2.12.7 describes why a complex
technology such as hybridization is estimated to range between $15,000
and $40,000 per vehicle for vocational vehicles in MY 2021. The engine
costs listed represent the cost of an average package of diesel engine
technologies as set out in Section II. Individual technology adoption
rates for engine packages are described in Section II.D. The details
behind all these costs are presented in draft RIA Chapter 2.12,
including the markups and learning effects applied and how the costs
shown here are weighted to generate an overall cost for the vocational
segment. We welcome comments on our technology cost assessments.

                                           Table V-20--Vocational Vehicle Technology Incremental Costs for the Proposal in the 2021 Model Year\a\ \b\
                                                                                [2012$]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Light HD                              Medium HD                               Heavy HD
                                                                 --------------------------------------------------------------------------------------------------------------------
                                                                                Multi-                                 Multi-                                 Multi-
                                                                     Urban       purpose      Regional      Urban       purpose      Regional      Urban       purpose      Regional
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Engine \c\......................................................         $293         $293         $293         $270         $270         $270         $270         $270         $270
Tires...........................................................            7            7            7            7            7            7            7            7            7
Transmission....................................................           81           81           81           81           81           81           81           81        2,852
Axle related....................................................           99           99           99           99           99           99          148          148          219
Weight Reduction................................................           27           27           48           27           27           41           27           27           34
Idle reduction..................................................           49           49           49           51           51           51            6            6            0
Electrification & hybridization.................................          547          547            0          861          861            0        1,437        1,437            0
Air Conditioning \d\............................................           22           22           22           22           22           22           22           22           22
                                                                 -------------------------------------------------------------------------------------------------------------------------------
    Total.......................................................        1,125        1,125          598        1,418        1,418          571        1,998        1,998        3,404
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2021 model year and are incremental to the costs of a vehicle meeting the Phase 1 standards. These costs include indirect costs via markups along with learning
  impacts. For a description of the markups and learning impacts considered in this analysis and how it impacts technology costs for other years, refer to Chapter 2 of the draft RIA (see draft
  RIA 2.12).
\b\Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the average cost expected for each of the indicated vehicle classes. To see the actual
  estimated technology costs exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see RIA 2.9 in particular).
\c\ Engine costs are for a light HD, medium HD or heavy HD diesel engine. We are projecting no additional costs beyond Phase 1 for gasoline vocational engines.
\d\ EPA's air conditioning standards are presented in Section V.C above.

    The estimated fleet average vocational vehicle package costs are
shown in Table V-21 for MY 2024. As shown, these range from
approximately $800 for MHD and LHD Regional vehicles, up to $4,800 for
HHD Regional vehicles. The increased costs above the MY 2021 values
reflect increased adoption rates of individual technologies, while the
individual technology costs are generally expected to remain the same
or decrease, as explained in the draft RIA Chapter 2.12. For example,
Chapter 2.12.7 presents MY 2024 hybridization costs that range from
$13,000 to $33,000 per vehicle for vocational vehicles. The engine
costs listed represent the average costs associated with the proposed
MY 2024 vocational diesel engine standard described in Section II.D.

                                           Table V-21--Vocational Vehicle Technology Incremental Costs for the Proposal in the 2024 Model Year\a\ \b\
                                                                                [2012$]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Light HD                              Medium HD                               Heavy HD
                                                                 --------------------------------------------------------------------------------------------------------------------
                                                                                Multi-                                 Multi-                                 Multi-
                                                                     Urban       purpose      Regional      Urban       purpose      Regional      Urban       purpose      Regional
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Engine \c\......................................................         $437         $437         $437         $405         $405         $405         $405         $405         $405
Tires...........................................................           17           17           17           17           17           17           23           23           23
Transmission....................................................          123          123          123          123          123          123          123          123        3,915
Axle related....................................................           90           90           90           90           90           90          136          136          224
Weight Reduction................................................           24           24           43           24           24           37           24           24           30
Idle reduction..................................................          119          119          119          125          125          125          224          224          217
Electrification & hybridization.................................          906          906            0        1,423        1,423            0        2,377        2,377            0
Air Conditioning \d\............................................           20           20           20           20           20           20           20           20           20
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    Total.......................................................        1,737        1,737          849        2,228        2,228          817        3,332        3,332        4,834
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2024 model year and are incremental to the costs of a vehicle meeting the Phase 1 standards. These costs include indirect costs via markups along with learning
  impacts. For a description of the markups and learning impacts considered in this analysis and how it impacts technology costs for other years, refer to Chapter 2 of the draft RIA (see draft
  RIA 2.12).
\b\Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the average cost expected for each of the indicated vehicle classes. To see the actual
  estimated technology costs exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see RIA 2.9 in particular).
\c\ Engine costs are for a light HD, medium HD or heavy HD diesel engine. We are projecting no additional costs beyond Phase 1 for gasoline vocational engines.
\d\ EPA's air conditioning standards are presented in Section V.C above.

    The estimated fleet average vocational vehicle package costs are
shown in Table V-22 for MY 2027. As shown, these range from
approximately $1,400 for MHD and LHD Regional vehicles, up to $7,400
for HHD Urban and Multipurpose vehicles. These two subcategories are
projected to have the higher-cost packages in MY 2027 due to an
estimated 18 percent adoption of HHD hybrids, which are estimated to
cost $31,000 per vehicle in MY 2027, as shown in Chapter 2.12.7 of the
draft RIA. These per-vehicle technology package costs were averaged
using our projections of vehicle populations in the nine regulatory
subcategories and do not correspond to the MOVES vehicle types. The
engine costs shown represent the average costs associated with the
proposed MY 2027 vocational diesel engine standard described in Section
II.D. For gasoline vocational vehicles, the agencies are projecting
adoption of Level 2 engine friction reduction with an estimated $68
added to the average SI vocational vehicle package cost in MY 2027,
which represents about 56 percent of those vehicles upgrading beyond
Level 1 engine friction reduction. Further details on how these SI
vocational vehicle costs were estimated are provided in the draft RIA
Chapter 2.9.
    Purchase prices of vocational vehicles can range from $60,000 for a
stake-bed landscape truck to over $400,000 for some transit buses. The
costs of the vocational vehicle standards can be put into perspective
by considering package costs estimated using MOVES vehicle types along
with typical prices for those vehicles. For example, a package cost of
$4,000 on a $60,000 short haul straight truck would represent an
incremental increase of about six percent of the vehicle purchase
price. Similarly, a package cost of $7,000 on a $200,000 refuse truck
would represent an incremental increase of less than four percent of
the vehicle purchase price. The vocational vehicle industry
characterization report in the docket includes additional examples of
vehicle prices for a variety of vocational applications.\317\
---------------------------------------------------------------------------

    \317\ See industry characterization, Note 260, above.

                                           Table V-22--Vocational Vehicle Technology Incremental Costs for the Proposal in the 2027 Model Year\a\ \b\
                                                                                [2012$]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Light HD                              Medium HD                               Heavy HD
                                                                 --------------------------------------------------------------------------------------------------------------------
                                                                                Multi-                                 Multi-                                 Multi-
                                                                     Urban       purpose      Regional      Urban       purpose      Regional      Urban       purpose      Regional
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Engine \c\......................................................         $471         $471         $471         $437         $437         $437         $437         $437         $437
Tires...........................................................           20           20           20           20           20           20           29           29           29
Transmission....................................................          244          244          267          244          244          267          244          244        2,986
Axle related....................................................           86           86           86           86           86           86          129          129          215
Weight Reduction................................................           29           29           46           29           29           40           29           29           35
Idle reduction..................................................          498          499          499          526          526          526          964          964          962
Electrification & hybridization.................................        2,122        2,122            0        3,336        3,336            0        5,571        5,571            0
Air Conditioning \d\............................................           19           19           19           19           19           19           19           19           19
                                                                 -------------------------------------------------------------------------------------------------------------------------------
    Total.......................................................        3,489        3,490        1,407        4,696        4,696        1,395        7,422        7,422        4,682
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2024 model year and are incremental to the costs of a vehicle meeting the Phase 1 standards. These costs include indirect costs via markups along with learning
  impacts. For a description of the markups and learning impacts considered in this analysis and how it impacts technology costs for other years, refer to Chapter 2 of the draft RIA (see draft
  RIA 2.12).
\b\ Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the average cost expected for each of the indicated vehicle classes. To see the actual
  estimated technology costs exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see RIA 2.9 in particular).
\c\ Engine costs are for a light HD, medium HD or heavy HD diesel engine. We are projecting no additional costs beyond Phase 1 for gasoline vocational engines.
\d\ EPA's air conditioning standards are presented in Section V.C above.

(3) Consistency of the Proposed Vocational Vehicle Standards With the
Agencies' Legal Authority
    NHTSA and EPA project the proposed standards to be achievable
within known design cycles, and we believe these standards, although
technology-forcing, would allow many different paths to compliance in
addition to the example outlined in this section. The proposed
standards are predicated on manufacturers implementing technologies
that we expect will be available in the time frame of these proposed
rules, although in some instances these technologies are still under
development or not widely deployed in the current vocational vehicle
fleet. Under the proposal, manufacturers would need to apply a range of
technologies to their vocational chassis, which the agencies believe
would be consistent with the agencies' respective statutory
authorities. We are projecting that most vehicles could adopt certain
of the technologies. For example, we project a 70 to 75 percent
application rate for stop-start idle reduction and advanced axle
lubrication. However, for other technologies, such as strong hybrids
and weight reduction, we are projecting adoption rates of ten percent
or less overall, with individual subcategories having adoption rates
greater or less than this. The proposed standards offer manufacturers
the flexibility to apply the technologies that make sense for their
business and customer needs.
    As discussed above, average per-vehicle costs associated with the
proposed 2027 MY standards are projected to be generally less than six
percent of the overall price of a new vehicle. The cost-effectiveness
of these proposed vocational vehicle standards in dollars per ton is
similar to the cost effectiveness estimated for light-duty trucks in
the 2017-2025 light duty greenhouse gas standards, which the agencies
have found to be highly cost effective.\318\ In addition, the
vocational vehicle standards are clearly effective from a net benefits
perspective (see draft RIA Chapter 11.2). Therefore, the agencies
regard the cost of the proposed standards as reasonable.
---------------------------------------------------------------------------

    \318\ See Chapter 5.3 of the final RIA for the MY 2017-2025
Light-Duty GHG Rule, available at http://www.epa.gov/otaq/climate/documents/420r12016.pdf.
---------------------------------------------------------------------------

    The agencies note that while the projected costs are significantly
greater than the costs projected for Phase 1, we still consider these
costs to be reasonable, especially given that the first vehicle owner
may see the technologies pay for themselves in many cases. As discussed
above, the usual period of ownership for a vocational vehicle reflects
a lengthy trade cycle that may often exceed seven years. For most
vehicle types evaluated, the cost of these technologies, if passed on
fully to customers, would be recovered within five years or less due to
the associated fuel savings, as shown in the payback analysis included
in Section IX and in the draft RIA Chapter 7.1. Specifically, in Table
7-30 of the draft RIA Chapter 7.1.3, a summary is presented with
estimated payback periods for each of the MOVES vocational vehicle
types, using the annual vehicle miles traveled from the MOVES model for
each vehicle type. As shown, the vocational vehicle type with the
shortest payback would be intercity buses (less than one year), while
most other vehicles (with the exception of school buses and motor
homes) are projected to see paybacks in the fifth year or sooner.
    The agencies note further that although the proposal is technology-
forcing (especially with respect to driveline improvements) and the
estimated costs for each subcategory vary considerably (by a factor of
five in some cases), these costs represent only one of many possible
pathways to compliance for manufacturers. Manufacturers retain leeway
to develop alternative compliance paths, increasing the likelihood of
the standards' successful implementation. Based on available
information, the agencies believe the proposed standards are
technically feasible within the lead time provided, are cost effective
while accounting for the fuel savings (see draft RIA Chapter 7.1.4),
and have no apparent adverse collateral potential impacts (e.g., there
are no projected negative impacts on safety or vehicle utility).
    The proposed standards thus appear to represent a reasonable choice
under Section 202(a) of the CAA and the maximum feasible under NHTSA's
EISA authority at 49 U.S.C. 32902(k)(2). The agencies believe that the
proposed standards are consistent with their respective authorities.
Based on the information currently before the agencies, we believe that
the preferred alternative would be maximum feasible and reasonable for
the vocational segment with a progression of standards reaching full
implementation in MY 2027.
    Nevertheless, as discussed in Section I. A. (1) and in Section X
(Alternatives), the agencies seek comment on the feasibility of
Alternative 4, which the agencies may determine is maximum feasible and
reasonable depending on comments and information received during the
comment period. This alternative is discussed in detail below because
it may be possible for manufacturers to accelerate product development
cycles enough to reach the required levels by the 2024 model year.
Thus, the agencies may conclude in the final rules that Alternative 4,
or some elements of this alternative, would be maximum feasible and
appropriate under CAA section 202 (a)(1) and (2), depending on
information and comments received. The agencies seek comments to assist
us in making that determination.

D. Alternative Vocational Vehicle Standards Considered

    The agencies have analyzed vocational vehicle standards other than
the proposed standards. These alternatives, listed in Table III-22, are
described in detail in Section X of this preamble and the draft RIA
Chapter 11.

     Table V-23--Summary of Alternatives Considered for the Proposed
                               Rulemaking
------------------------------------------------------------------------

------------------------------------------------------------------------
Alternative 1..........................  No action alternative
Alternative 2..........................  Less stringent than the
                                          proposed alternative, applying
                                          off-the-shelf technologies
Alternative 3 (Proposed Alternative)...  Proposed alternative fully
                                          phased-in by MY 2027
Alternative 4..........................  Same stringency as proposed
                                          alternative, except phasing in
                                          faster, by MY 2024
Alternative 5..........................  More stringent alternative,
                                          based on higher adoption rates
                                          of advanced technologies
------------------------------------------------------------------------

    NHTSA and EPA are considering an Alternative 4 that achieves the
same level of stringency as the preferred alternative, except it would
provide less lead time, reaching its most stringent level three years
earlier than the

preferred alternative, that is in MY 2024. The agencies project that
the same selection of technology options would be available to
manufacturers regardless of what alternative is chosen. The preferred
alternative would allow greater lead time to manufacturers to select
and develop technologies for their vehicles.
    The agencies have outstanding questions regarding relative risks
and benefits of Alternative 4 due to the time frame envisioned by that
alternative. If the agencies receive relevant information supporting
the feasibility of Alternative 4, the agencies may consider
establishing vocational vehicle standards that provide more overall
reductions than what we are proposing if we deem them to be maximum
feasible and reasonable for NHTSA and EPA, respectively. See the draft
RIA Chapter 11.2.2 for a summary of costs and benefits that compares
the proposed Phase 2 vocational vehicle program with the costs and
benefits of other vocational vehicle alternatives considered.
    In the paragraphs that follow, the agencies present the derivation
of the Alternative 4 vocational vehicle standards. For currently
developing technologies where we project an adoption rate that could
present potential risks or challenges, we seek comment on the cost and
effectiveness of such technology. Further, the agencies seek comment on
the potential for adoption of developing technologies into the
vocational vehicle fleet, as well as the extent to which the more
accelerated alternative vocational vehicle standards may depend on such
technology.
(1) Adoption Rates for Derivation of Alternative 4 Vocational Vehicle
Standards
    In developing the Alternative 4 standards, the agencies are
projecting a set of technology packages in MY 2024 that is identical to
those projected for the final phase-in year of the preferred
alternative. Because these are the same for each subcategory, the GEM
inputs modeled to derive the level of the MY 2024 Alternative 4
standards can be found in Table V-19, which presents the GEM inputs
used to derive the level of the MY 2027 proposed standards. In the
package descriptions below, the agencies outline technology-specific
adoption rates in MY 2021 for Alternative 4 and offer insights on what
market conditions could enable reaching adoption rates that would
achieve the full implementation levels of stringency with less lead
time.
    For transmissions including hybrids, the agencies project for
Alternative 4 that 50 percent of vocational vehicles would have one or
more of the transmission technologies identified above in this section
applied by MY 2021. This includes 25 percent deeply integrated
conventional transmissions that would be recognized over the powertrain
test, 10 percent DCT, 11 percent adding two gears (except zero for HHD
Regional), and nine percent hybrids for vehicles certified in the
Multi-Purpose and Urban subcategories, which we estimate would be five
percent overall. In this alternative, the agencies project 21 percent
of the vocational vehicles with manual transmissions in the HHD
Regional subcategory would upgrade to either an AMT, DCT, or automatic
transmission. The increased projection of driveline integration would
mean that more manufacturers would need to overcome data-sharing
barriers. In this alternative, we project that manufacturers would need
to conduct additional research and development to achieve overall
application of five percent hybrids. In the draft RIA Chapter 7.1, the
agencies have estimated costs for this additional accelerated research.
Comments are requested on the expected costs to accelerate hybrid
development to meet the projected adoption rates of this alternative.
    For advanced axle lubricants, the agencies are projecting the same
75 percent adoption rate in MY 2021 as in the proposed program. For
part time or full time 6x2 axles, the agencies project the HHD Regional
vocational vehicles could apply this at the 60 percent adoption rate in
MY 2021, where this level wouldn't be reached until MY 2024 in the
proposed program. One action that could enable this to be achieved is
if information on the reliability of these systems were to be
disseminated to more fleet owners by trustworthy sources.
    For lower rolling resistance tires in this alternative, the
agencies project the same adoption rates of LRR tires as in the
proposed program for MY 2021, because we don't expect tire suppliers
would be able to make greater improvements for the models that are
fitted on vocational vehicles in that time frame. The tire research
that is being conducted currently is focused on models for tractors and
trailers, and we project further improved LRR tires would not be
commercially available for vocational vehicles in the early
implementation years of Phase 2.
    For the adoption rate of LRR tires in MY 2024 to reach the level
projected for MY 2027 in the proposed program, tire suppliers could
promote their most efficient products to vocational vehicle
manufacturers to achieve equivalent improvements with less lead time.
Depending on how tire manufacturers focus their research and product
development, it is possible that more of the LRR tire advancements
being applied for tractors and trailers could be applied to vocational
vehicles. To see the specific projected adoption rates of different
levels of LRR tires for Alternative 4, see columns three and five of
Table V-16 above.
    For workday idle technologies, the agencies project an adoption
rate of 12 percent stop-start in the six MHD and LHD subcategories for
MY 2021 and zero for the HHD vehicles, on the expectation that
manufacturers would have fewer challenges in the short term in bringing
this technology to market for vehicles with lower power demands and
lower engine inertia. In this alternative, the agencies project the
overall workday idle adoption rate would approach 100 percent, such
that any vehicle without stop-start (except HHD Regional) would apply
neutral idle in MY 2021. These adoption raters consider a more
aggressive investment by manufacturers in developing these
technologies. Estimates of research and development costs for this
alternative are presented in the draft RIA Chapter 7.1.
    For weight reduction, in this alternative, the agencies project the
same adoption rates of a 200-lb lightweighting package as in the
proposal for each subcategory in MY 2021, which is four to seven
percent. Table V-24 shows the GEM inputs used to derive the level of
the Alternative 4 MY 2021 standards.

                                Table V--24--GEM Inputs Used To Derive Alternative 4 MY 2021 Vocational Vehicle Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                   Class 2b-5                                                  Class 6-7                            Class 8
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Multi-                              Multi-                              Multi-
                          Urban                             purpose    Regional      Urban      purpose    Regional      Urban      purpose    Regional
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Alternative 4 CI Engine a
--------------------------------------------------------------------------------------------------------------------------------------------------------
                            2021 MY 7L, 200 hp Engine          2021 MY 7L, 270 hp Engine
                                                            2021 MY 11L, 345 hp     2021 MY
                                                                  Engine          15L 455hp
                                                                                Engine
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Transmission (improvement factor)
--------------------------------------------------------------------------------------------------------------------------------------------------------
0.045...................................................       0.04       0.014       0.045       0.041       0.015       0.045       0.041       0.018
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Axle (improvement factor)
--------------------------------------------------------------------------------------------------------------------------------------------------------
0.004...................................................      0.004       0.004       0.004       0.004       0.004       0.004       0.004       0.015
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Stop-Start (adoption rate)
--------------------------------------------------------------------------------------------------------------------------------------------------------
12%.....................................................        12%         12%         12%         12%         12%          0%          0%          0%
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Neutral Idle (adoption rate)
--------------------------------------------------------------------------------------------------------------------------------------------------------
88%.....................................................        88%         88%         88%         88%         88%         90%         90%          0%
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Steer Tires (CRR kg/metric ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
7.1.....................................................        7.1         7.1         7.1         7.1         7.1         7.1         7.1         7.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Drive Tires (CRR kg/metric ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
7.5.....................................................        7.5         7.5         7.5         7.5         7.5         7.5         7.5         7.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Weight Reduction (lb)
--------------------------------------------------------------------------------------------------------------------------------------------------------
8.......................................................          8          14           8           8          12           8           8          10
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note:
\a\ SI engines were not simulated in GEM, rather a gas/diesel adjustment factor was applied to the results.

(2) Possible Alternative 4 Standards
    Because the MY 2024 Alternative 4 standards are the same as the
proposed standards for MY 2027 for each subcategory, these numerical
standards can be found in Table V-8 and Table V-9, which present EPA's
and NHTSA's proposed MY 2027 standards, respectively. Table V-25 and
Table V-26 present the Alternative 4 vocational vehicle standards for
the initial year of MY 2021. These represent incremental improvements
over the MY 2017 baseline of six to seven percent for SI-powered
vocational vehicles and nine percent for CI-powered vocational
vehicles.

   Table V-25--Alternative 4 EPA CO2 Standards for MY2021 Class 2\b\-8
                           Vocational Vehicles
------------------------------------------------------------------------
                                   Light heavy-    Medium    Heavy heavy-
            Duty cycle              duty Class   heavy-duty   duty Class
                                       2b-5      Class 6-7        8
------------------------------------------------------------------------
  Alternative EPA Standard for Vehicle with CI Engine Effective MY2021
                           (gram CO2/ton-mile)
------------------------------------------------------------------------
Urban............................          288          183          193
Multi-Purpose....................          297          185          196
Regional.........................          309          181          185
------------------------------------------------------------------------
  Alternative EPA Standard for Vehicle with SI Engine Effective MY2021
                           (gram CO2/ton-mile)
------------------------------------------------------------------------
Urban............................          313          199          210
Multi-Purpose....................          323          201          212
Regional.........................          336          197          201
------------------------------------------------------------------------

     Table V-26--Alternative 4 NHTSA Fuel Consumption Standards for MY2021 Class 2\b\-8 Vocational Vehicles
----------------------------------------------------------------------------------------------------------------
                                                     Light heavy-duty    Medium heavy-duty     Heavy heavy-duty
                    Duty cycle                          Class 2b-5           Class 6-7             Class 8
----------------------------------------------------------------------------------------------------------------
 Alternative NHTSA Standard for Vehicle with CI Engine Effective MY 2021 (Fuel Consumption gallon per 1,000 ton-
                                                      mile)
----------------------------------------------------------------------------------------------------------------
Urban............................................              28.2908              17.9764              18.9587
Multi-Purpose....................................              29.1749              18.1729              19.2534
Regional.........................................              30.3536              17.7800              18.1729
----------------------------------------------------------------------------------------------------------------
 Alternative NHTSA Standard for Vehicle with SI Engine Effective MY 2021 (Fuel Consumption gallon per 1,000 ton-
                                                      mile)
----------------------------------------------------------------------------------------------------------------
Urban............................................              35.2200              22.3923              23.6300
Multi-Purpose....................................              36.3452              22.6173              23.8551
Regional.........................................              37.8080              22.1672              22.6173
----------------------------------------------------------------------------------------------------------------

(3) Costs Associated With Alternative 4 Standards
    The agencies have estimated the costs of the technologies expected
to be used to comply with the Alternative 4 standards, as shown in
Table V-27 for MY2021. Fleet average costs are shown for light, medium
and heavy HD vocational vehicles in each duty-cycle-based subcategory--
Urban, Multi-Purpose, and Regional. As shown in Table V-27, in MY 2021
these range from approximately $800 for MHD and LHD Regional vehicles,
to $4,300 for HHD Urban and Multipurpose vehicles. Those two
subcategories are projected to have the higher-cost packages in MY 2021
due to an estimated 9 percent adoption of HHD hybrids, which are
estimated to cost $40,000 per vehicle in MY 2021, as shown in Chapter
2.12.7 of the draft RIA. For more specific information about the
agencies' estimates of per-vehicle costs, please see the draft RIA
Chapter 2.12. The engine costs listed represent the cost of an average
package of diesel engine technologies with Alternative 4 adoption rates
described in Section II.D.2(e). The details behind all these costs are
presented in draft RIA Chapter 2.12, including the markups and learning
effects applied and how the costs shown here are weighted to generate
an overall cost for the vocational segment.

                 Table V-27--Vocational Vehicle Technology Incremental Costs for Alternative 4 Standards in the 2021 Model Year \a\ \b\
                                                                         (2012$)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Light HD                        Medium HD                         Heavy HD
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Multi-                           Multi-                           Multi-
                                                         Urban     purpose    Regional    Urban     purpose    Regional    Urban     purpose    Regional
--------------------------------------------------------------------------------------------------------------------------------------------------------
Engine \c\...........................................       $372       $372       $372       $345       $345       $345       $345       $345       $345
Tires................................................          7          7          7          7          7          7          7          7          7
Transmission.........................................        148        148        148        148        148        148        148        148      2,042
Axle related.........................................         99         99         99         99         99         99        148        148        243
Weight Reduction.....................................         27         27         48         27         27         41         27         27         34
Idle reduction.......................................        110        110        110        116        116        116          8          8          0
Electrification & hybridization......................      1,384      1,384          0      2,175      2,175          0      3,633      3,633          0
Air Conditioning \d\.................................         22         22         22         22         22         22         22         22         22
                                                      --------------------------------------------------------------------------------------------------
    Total............................................      2,169      2,169        805      2,938      2,938        777      4,337      4,337      2,693
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2021 model year and are incremental to the costs of a vehicle meeting the Phase 1 standards. These costs include indirect
  costs via markups along with learning impacts. For a description of the markups and learning impacts considered in this analysis and how it impacts
  technology costs for other years, refer to Chapter 2 of the draft RIA (see draft RIA 2.12).
\b\ Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the average cost expected for each of the
  indicated vehicle classes. To see the actual estimated technology costs exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see RIA 2.9
  in particular).
\c\ Engine costs are for a light HD, medium HD or heavy HD diesel engine. We are projecting no additional costs beyond Phase 1 for gasoline vocational
  engines.
\d\ EPA's air conditioning standards are presented in Section V.C above.

    The estimated costs of the technologies expected to be used to
comply with the Alternative 4 standards for MY2024 are shown in Table
V-28. As shown, these range from approximately $1,500 for MHD and LHD
Regional vehicles to $7,900 for HHD Urban and Multipurpose vehicles.
These two subcategories are projected to have the higher-cost packages
in MY 2024 due to an estimated 18 percent adoption of HHD hybrids,
which are estimated to cost $33,000 per vehicle in MY 2024, as shown in
Chapter 2.12.7 of the draft RIA. The engine costs listed represent the
cost of an average package of diesel engine technologies with
Alternative 4 adoption rates described in Section II.D.2(e). For
gasoline vocational vehicles, the agencies are projecting adoption of
Level 2 engine friction reduction with an estimated $74 added to the
average SI vocational vehicle package cost in MY 2024, which represents
about 56 percent of those vehicles upgrading beyond Level 1 engine
friction reduction. Further

details on how these SI vocational vehicle costs were estimated are
provided in the draft RIA Chapter 2.9.

                   Table V-28--Vocational Vehicle Technology Incremental Costs for Alternative 4 Standards in the 2024 Model Year \a\
                                                                         (2012$)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Light HD                        Medium HD                         Heavy HD
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Multi-                           Multi-                           Multi-
                                                         Urban     purpose    Regional    Urban     purpose    Regional    Urban     purpose    Regional
--------------------------------------------------------------------------------------------------------------------------------------------------------
Engine \c\...........................................       $493       $493       $493       $457       $457       $457       $457       $457       $457
Tires................................................         26         26         26         26         26         26         40         40         40
Transmission.........................................        256        256        280        256        256        280        256        256      3,123
Axle related.........................................         90         90         90         90         90         90        136        136        224
Weight Reduction.....................................         30         30         49         30         30         43         30         30         37
Idle reduction.......................................        561        524        524        592        553        553      1,014      1,014      1,011
Electrification & hybridization......................      2,264      2,264          0      3,559      3,559          0      5,943      5,943          0
Air Conditioning \d\.................................         20         20         20         20         20         20         20         20         20
                                                      --------------------------------------------------------------------------------------------------
    Total............................................      3,741      3,704      1,482      5,030      4,992      1,469      7,895      7,895      4,912
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2024 model year and are incremental to the costs of a vehicle meeting the Phase 1 standards. These costs include indirect
  costs via markups along with learning impacts. For a description of the markups and learning impacts considered in this analysis and how it impacts
  technology costs for other years, refer to Chapter 2 of the draft RIA (see draft RIA 2.12).
\b\ Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the average cost expected for each of the
  indicated vehicle classes. To see the actual estimated technology costs exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see RIA 2.9
  in particular).
\c\ Engine costs shown are for a light HD, medium HD or heavy HD diesel engine. For gasoline-powered vocational vehicles we are projecting $74 of
  additional engine-based costs beyond Phase 1.
\d\ EPA's air conditioning standards are presented in Section V.C above.

E. Compliance Provisions for Vocational Vehicles

    We welcome comment on all aspects of the compliance program,
including those where we would adopt a provision without change in
Phase 2.
(1) Application and Certification Process
    The agencies propose to continue to use GEM to determine compliance
with the proposed vehicle fuel efficiency and CO2 standards.
Because the agencies are proposing to modify GEM to recognize inputs in
addition to those recognized under Phase 1, there is a consequent
proposed requirement that manufacturers or component suppliers conduct
component testing to generate those input values. See Section II for
details of engine testing and GEM inputs for engines.
    As described above in Section I, the agencies propose to continue
the Phase 1 compliance process in terms of the manufacturer
requirements prior to the effective model year, during the model year,
and after the model year. The information that would be required to be
submitted by manufacturers is set forth in 40 CFR 1037.205, 49 CFR
537.6, and 49 CFR 537.7. EPA would continue to issue certificates upon
approval based on information submitted through the VERIFY database
(see 40 CFR 1037.255). End of year reports would continue to include
the GEM results for all of the configurations built, along with credit/
deficit balances, if applicable (see 40 CFR 1037.250 and 1037.730).
(a) GEM Inputs
    In Phase 1, there were two inputs to GEM for vocational vehicles:
     Steer tire coefficient of rolling resistance, and
     Drive tire coefficient of rolling resistance
    As discussed above in Section II and III.D, there are several
additional inputs that are proposed for Phase 2. In addition to the
steer and drive tire CRR, the proposed inputs include the following:
     Engine fuel map,
     Engine full-load torque curve,
     Engine motoring curve,
     Transmission type,
     Transmission gear ratios,
     Drive axle ratio,
     Loaded tire radius for drive and steer tires,
     Idle Reduction,
     Weight Reduction, and
     Other pre-defined off-cycle technologies.
(i) Driveline Inputs
    As with tractors, for each engine family, an engine fuel map, full
load torque curve, and motoring curve would be generated by engine
manufacturers as inputs to GEM. The test procedures for the torque and
motoring curves are found in proposed 40 CFR part 1065. Section
II.D.1.b describes these proposed procedures as well as the proposed
new procedure for generating the engine fuel map. Also similar to
tractors, transmission specifications would be input to GEM. Any number
of gears could be entered with a numerical ratio for each, and
transmission type would be selectable as either a Manual, Automated
Manual, Automatic, or Dual Clutch transmission.
    As part of the driveline information needed to run GEM, drive axle
ratio would be a user input. If a configuration has a two-speed axle,
the agencies propose that a manufacturer may enter the ratio that is
expected to be engaged most often. We request comment on whether the
agencies should allow this choice. Two-speed axles are typically
specified for heavy-haul vocational vehicles, where the higher
numerical ratio axle would be engaged during transient driving
conditions and to deliver performance needed on work sites, while the
lower numerical ratio axle would be engaged during highway driving. The
agencies request comment on whether we should require GEM to be run
twice, once with each axle ratio, where the output over the highway
cycles would be used from the run with the lower axle ratio, and the
output over the transient cycle would be used from the run with the
higher axle ratio.
    Tire size would be a new input to GEM that is necessary for the
model to simulate the performance of the vehicle.

The draft RIA Chapter 3 includes a description of how to measure tire
size. For each model and nominal size of a tire, there are numerous
possible sizes that could be measured, depending on whether the tire is
new or ``grown,'' meaning whether it has been broken in for at least
200 miles. Size could also vary based on load and inflation levels, air
temperature, and tread depth. The agencies request comment on aspects
of measuring and reporting tire size that could be specified by rule,
to avoid any unnecessary compliance burden of the Phase 2 program.
(ii) Idle Reduction Inputs
    Based on user inputs derived from engine testing described in
Section II and draft RIA Chapter 3, GEM would calculate CO2
emissions and fuel consumption at both zero torque (neutral idle) and
with torque set to Curb-Idle Transmission Torque for automatic
transmissions in ``drive'' (as defined in 40 CFR 1065.510(f)(4) for
variable speed engines) for use in the CO2 emission
calculation in 40 CFR 1037.510(b). The proposed regulations at 40 CFR
part 1065 specify that that there must be two consecutive reference
zero load idle points to establish periods of zero load idle for
purposes of calculating total work over an engine test cycle. These two
idle points from the engine test would be used in GEM for purposes of
calculating emissions during vehicle idling over the vocational vehicle
test cycles.
    The agencies welcome comments on the inclusion of these
technologies into GEM in Phase 2.
(iii) Weight Reduction Inputs
    In Phase 1, the agencies adopted tractor regulations that provided
manufacturers with the ability to utilize high strength steel and
aluminum components for weight reduction without the burden of entering
the curb weight of every tractor produced. In Phase 2, the agencies
propose to apply relevant weights from the tractor lookup table to
vocational vehicles. As noted above, the agencies are proposing to
recognize weight reduction by allocating one half of the weight
reduction to payload in the denominator, while one half of the weight
reduction would be subtracted from the overall weight of the vehicle in
GEM.
    To adapt the tractor table for vocational vehicles, the agencies
propose to add lookup values for vehicles in lower weight classes. We
believe it is appropriate to also recognize the weight reduction
associated with 6x2 axles.\319\ Components available for vocational
vehicle manufacturers to select for weight reduction are shown below in
Table V-29, below. We are also proposing to assign a fixed weight
increase to natural gas fueled vehicles to reflect the weight increase
of natural gas fuel tanks versus gasoline or diesel tanks. These are
shown as negative values in Table V-29 to indicate that GEM would
internally compute these values in an inverse manner as would be
computed for a weight reduction, for which the GEM input is a positive
numerical value. We welcome comments on all aspects of weight reduction
approaches and potential weight increases as a byproduct of technology
application.
---------------------------------------------------------------------------

    \319\ See NACFE Confidence Findings on the Potential of 6x2
Axles, Note 152 above.

               Table V--29 Proposed Phase 2 Weight Reduction Technologies for Vocational Vehicles
----------------------------------------------------------------------------------------------------------------
                                                                                Vocational Vehicle Class
                 Component                             Material           --------------------------------------
                                                                            Class 2b-5   Class 6-7     Class 8
----------------------------------------------------------------------------------------------------------------
Axle Hubs--Non-Drive......................  Aluminum.....................             40                      40
Axle Hubs--Non-Drive......................  High Strength Steel..........              5                       5
Axle--Non-Drive...........................  Aluminum.....................             60                      60
Axle--Non-Drive...........................  High Strength Steel..........             15                      15
Brake Drums--Non-Drive....................  Aluminum.....................             60                      60
Brake Drums--Non-Drive....................  High Strength Steel..........              8                       8
Axle Hubs--Drive..........................  Aluminum.....................             40                      80
Axle Hubs--Drive..........................  High Strength Steel..........             10                      20
Brake Drums--Drive........................  Aluminum.....................             70                     140
Brake Drums--Drive........................  High Strength Steel..........             5.5                     11
Clutch Housing............................  Aluminum.....................             34                      40
Clutch Housing............................  High Strength Steel..........              9                      10
Suspension Brackets, Hangers..............  Aluminum.....................             67                     100
Suspension Brackets, Hangers..............  High Strength Steel..........             20                      30
Transmission Case.........................  Aluminum.....................             45                      50
Transmission Case.........................  High Strength Steel..........             11                      12

Crossmember--Cab..........................  Aluminum.....................           10           14           15
Crossmember--Cab..........................  High Strength Steel..........            2            4            5
Crossmember--Non-Suspension...............  Aluminum.....................           15           18           21
Crossmember--Non-Suspension...............  High Strength Steel..........            5            6            7
Crossmember--Suspension...................  Aluminum.....................           15           20           25
Crossmember--Suspension...................  High Strength Steel..........            4            5            6
Driveshaft................................  Aluminum.....................           12           40           50
Driveshaft................................  High Strength Steel..........            5           10           12
Frame Rails...............................  Aluminum.....................          120          300          440
Frame Rails...............................  High Strength Steel..........           24           40           87
Wheels--Dual..............................  Aluminum.....................          126          126          210
Wheels--Dual..............................  High Strength Steel..........           48           48           80
Wheels--Dual..............................  Lightweight Aluminum.........          180          180          300
Wheels--Wide Base Single..................  Aluminum.....................          278          278          556
Wheels--Wide Base Single..................  High Strength Steel..........          168          168          336
Wheels--Wide Base Single..................  Lightweight Aluminum.........          294          294          588

Permanent 6x2 Axle Configuration..........  Multi........................          N/A          N/A          300

CI Liquified Natural Gas Vocational         Multi........................             \320\ \321\ -600
 Vehicle.
SI Compressed Natural Gas Vocational        Multi........................                   -525
 Vehicle.
CI Compressed Natural Gas Vocational        Multi........................                   -900
 Vehicle.
----------------------------------------------------------------------------------------------------------------

(b) Test Procedures
    Powertrain families aredefined in Section II.C.3.b, and powertrain
test procedures are discussed in the draft RIA Chapter 3. The agencies
propose that the results from testing a powertrain configuration using
the matrix of tests described in draft RIA Chapter 3.6 could be applied
broadly across all vocational vehicles in which that powertrain would
be installed.
---------------------------------------------------------------------------

    \320\ See National Energy Policy Institute (2012), Note 200
above.
    \321\ See Westport presentation (2013), Note 201, above.
---------------------------------------------------------------------------

    As in Phase 1, the rolling resistance of each tire would 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 would input the CRR values for
the drive and steer tires separately into the GEM. For vocational
vehicles in Phase 2, the agencies propose that the vehicle load would
be distributed with 30 percent of the load over the steer tires and 70
percent of the load over the drive tires. With these data entered, the
amount of GHG reduction attributed to tire rolling resistance would be
incorporated into the overall vehicle compliance value.
(c) Useful Life and In-Use Standards
    Section 202(a)(1) of the CAA specifies that emission standards are
to be applicable for the useful life of the vehicle. The standards that
EPA and NHTSA are proposing would apply to individual vehicles and
engines at production and in use. NHTSA is not proposing in-use
standards for vehicles and engines.
    Manufacturers may be required to submit, as part of the application
for certification, an engineering analysis showing that emission
control performance will not deteriorate during the useful life, with
proper maintenance. If maintenance will be required to prevent or
minimize deterioration, a demonstration may be required that this
maintenance will be performed in use. See 40 CFR 1037.241.
    EPA is proposing to continue the Phase 1 approach to adjustment
factors and deterioration factors. The technologies on which the Phase
1 vocational vehicle standards were predicated were not expected to
have any deterioration of GHG effectiveness in use. However, the
regulations provided a process for manufacturers to develop
deterioration factors (DF) if they needed. We anticipate that some
hybrid powertrain systems may experience some deterioration of
effectiveness with age of the energy storage device. We believe the
regulations in place currently provide adequate instructions to
manufacturers for developing DF where needed. We request comment on
whether any changes to the DF process are needed.
    As with engine certification, a manufacturer must provide evidence
of compliance through the regulatory useful life of the vehicle.
Factors influencing vehicle-level GHG performance over the life of the
vehicle fall into two basic categories: Vehicle attributes and
maintenance items. Each category merits different treatment from the
perspective of assessing useful life compliance, as each has varying
degrees of manufacturer versus owner/operator responsibility.
    For vocational vehicles, attributes generally refers to components
that are installed by the manufacturer to meet the standard, whose
reduction properties are assessed at the time of certification, and
which are expected to last the full life of the vehicle with
effectiveness maintained as new for the life of the vehicle with no
special maintenance requirements. To assess useful life compliance, we
are proposing to follow a design-based approach that would ensure that
the manufacturer has robustly designed these features so they can
reasonably be expected to last the useful life of the vehicle.
    For vocational vehicles, maintenance items generally refers to
items that are replaced, renewed, cleaned, inspected, or otherwise
addressed in the preventative maintenance schedule specified by the
vehicle manufacturer. Replacement items that have a direct influence on
GHG emissions are primarily tires and lubricants, but may also include
hybrid system batteries. Synthetic engine oil may be used by vehicle
manufacturers to reduce the GHG emissions of their vehicles.
Manufacturers may specify that these fluids be changed throughout the
useful life of the vehicle. If this is the case, the manufacturer
should have a reasonable basis that the owner/operator will use fluids
having the same properties. This may be accomplished by requiring (in
service documentation, labeling, etc.) that only these fluids can be
used as replacements. In this proposal, the only maintenance costs we
have quantified are those for tire replacement, as described in Section
IX.C.3 and the draft RIA Chapter 7.1. The agencies invite comments with
information related to maintenance costs that the agencies should
quantify for the final rules.
    For current non-hybrid technologies, if the vehicle remains in its
original certified condition throughout its useful life, it is not
believed that GHG emissions would increase as a result of service
accumulation. As in Phase 1, the agencies propose allowing the use of
an assigned deterioration factor of zero where appropriate in Phase 2;
however this does not negate the responsibility of the manufacturer to
ensure compliance with the emission standards throughout the useful
life. The vehicle manufacturer would be primarily responsible for
providing engineering analysis demonstrating that vehicle attributes
will last for the full useful life of the vehicle. We anticipate this
demonstration would show that components are constructed of
sufficiently robust materials and design practices so as not to become
dysfunctional under normal operating conditions.
    In Phase 1, EPA set the useful life for engines and vehicles with
respect to GHG emissions equal to the respective useful life periods
for criteria pollutants. In April 2014, as part of the Tier 3 light-
duty vehicle final rule, EPA extended the regulatory useful life period
for criteria pollutants to 150,000 miles or 15 years, whichever comes
first, for Class

2b and 3 pickup trucks and vans and some light-duty trucks (79 FR
23414, April 28, 2014). Class 2 through Class 5 heavy-duty vehicles
subject to the GHG standards described in this section for vocational
applications generally use the same kinds of engines, transmissions,
and emission controls as the Class 2b and 3 vehicles that are chassis-
certified to the criteria standards under 40 CFR part 86, subpart S.
EPA and NHTSA are therefore proposing that the Phase 2 GHG and fuel
consumption standards for vocational vehicles at or below 19,500 lbs
GVWR apply over the same useful life of 150,000 miles or 15 years. In
many cases, this will result in aligned useful-life values for criteria
and GHG standards. Where this longer useful life is not aligned with
the useful life that applies for criteria standards (generally in the
case of engine-based certification under 40 CFR part 86, subpart A),
EPA may revisit the useful-life values for both criteria and GHG
standards in a future rulemaking. For medium heavy-duty vehicles
(19,500 to 33,000 lbs GVWR) and heavy heavy-duty vehicles (above 33,000
lbs GVWR) EPA is proposing to keep the useful-life values from Phase 1,
which are 185,000 miles (or 10 years) and 435,000 miles (or 10 years),
respectively. EPA requests comment on this approach, including the
proposed values and the overall process envisioned for achieving the
long-term goal of adopting harmonized useful-life specifications for
criteria and GHG standards that properly represent the manufacturers'
obligation to meet emission standards over the expected service life of
the vehicles. EPA may also revisit the useful-life values that apply
for medium heavy-duty vehicles and heavy heavy-duty vehicles.
    One technology option for vocational vehicle manufacturers to
reduce GHG emissions is to use a smaller engine, perhaps in conjunction
with a hybrid powertrain. This could lead to a situation where the
engine and the vehicle are subject to emission standards over different
useful-life periods. For example, an urban bus (heavy heavy-duty
vehicle), might be able to use a medium heavy-duty engine, or even a
light heavy-duty engine. While such a mismatch in useful life values
could be confusing, we don't believe it poses any particular policy
problem that we need to address. EPA requests comment on the
possibility of mismatched engine and vehicle useful-life values and on
any possible implications this may have for manufacturers' ability to
design, certify, produce, and sell their engines and vehicles.
(d) Assigning Vehicles to Test Cycles
    The agencies propose the following logic for deciding which chassis
configurations would be assigned to each of the three proposed
vocational duty cycles and thus regulatory subcategories:
     A vehicle would be certified over the Multipurpose Duty
Cycle, unless one of the following conditions warrants certifying over
either the Regional or Urban cycle.
     If the vehicle is powered by a CI engine, use the Regional
Duty Cycle if the resulting value from the calculation described in
Equation V-1 is less than 75 percent.
     If the vehicle is powered by a SI engine, use the Regional
Duty Cycle if the resulting value from the calculation described in
Equation V-1 is less than 45 percent.
[GRAPHIC] [TIFF OMITTED] TP13JY15.004

Where:

CutpointRegional is the percent of maximum engine test
speed that is achieved at a vehicle speed of 65 mph,
SLR is the static loaded tire radius entered into GEM as specified
in the regulations,
Axle ratio is the drive axle ratio that entered into GEM as
specified in the regulations,
Trans ratio is the ratio of the top transmission gear that is not
permanently locked out,
fntest is the maximum engine test speed as defined at 40
CFR 1065.610, and C is a constant equal to:
[GRAPHIC] [TIFF OMITTED] TP13JY15.005

     If a vehicle is powered by a CI engine, use the Urban Duty
Cycle if the resulting value from the calculation described in Equation
V-2 is greater than 90 percent.
     If a vehicle is powered by a SI engine, use the Urban Duty
Cycle if the resulting value from the calculation described in Equation
V-2 is greater than 50 percent.
[GRAPHIC] [TIFF OMITTED] TP13JY15.006

Where:
CutpointUrban is the percent of maximum engine test speed
that is achieved at a vehicle speed of 55 mph,
SLR is the static loaded tire radius entered into GEM as specified
in the regulations,
Axle ratio is the drive axle ratio that is entered into GEM as
specified in the regulations,
Trans ratio is the ratio of the top transmission gear that is not
permanently locked out,
fntest is the maximum engine test speed as defined at 40
CFR 1065.610, and C is a constant equal to:
[GRAPHIC] [TIFF OMITTED] TP13JY15.007

    The agencies ran GEM with many vocational vehicle configurations to
develop a data set with which we could assess appropriate cutpoints for
the above equations. The configurations varied primarily by the engine
model, fuel type, and axle ratio. See the draft RIA Chapter 2.9.2 for
further details on the assessment process for these proposed cutpoints.
    The agencies realize that there are vocational vehicles for which
the above logic may not result in an appropriate assignment of test
cycle. Therefore we are proposing an exception that would enable any
vehicle with a hybrid drivetrain to certify over the Urban test cycle.
Further, we are proposing that the following vehicles must be certified
using the Regional cycle: intercity coach buses, recreational vehicles,
and vehicles whose engine is exclusively certified over the SET. We are
also proposing to allow manufacturers to request a different duty
cycle. We request comment on this approach, and whether we should allow
manufacturers to have complete freedom to select a test cycle without
any need for EPA or NHTSA approval.
(2) Other Compliance Provisions
(a) Emission Control Labels
    The agencies consider it crucial that authorized compliance
inspectors are able to identify whether a vehicle is certified, and if
so whether it is in its certified condition. To facilitate this
identification in Phase 1, EPA adopted labeling provisions for
vocational vehicles that included several items. The Phase 1 vocational
vehicle label must include the manufacturer, vehicle identifier such as
the Vehicle Identification Number, vehicle family, regulatory
subcategory, date of manufacture, compliance statements, and emission
control system identifiers (see 40 CFR 1037.135). In Phase 1, the
vocational vehicle emission control system identifier is tire rolling
resistance, plus any innovative and advanced technologies.
    The number of proposed emission control systems for greenhouse gas
emissions in Phase 2 has increased significantly. For example, the
engine, transmission, axle configuration, tire radius, and idle
reduction system are control systems that can be evaluated on-cycle in
Phase 2 (i.e. these technologies' performance can now be input to GEM),
but could not be evaluated in Phase 1. Due to the complexity in
determining greenhouse gas emissions as proposed in Phase 2, the
agencies do not believe that we can unambiguously determine whether or
not a vehicle is in a certified condition through simply comparing
information that could be made available on an emission control label
with the components installed on a vehicle. Therefore, EPA proposes to
remove the requirement to include the emission control system
identifiers required in 40 CFR 1037.135(c)(6) and in Appendix III to 40
CFR part 1037 from the emission control labels for vocational vehicles
certified to the primary Phase 2 standards. However, the agencies may
finalize requirements to maintain some label content to facilitate a
limited visual inspection of key vehicle parameters that can be readily
observed. Such requirements may be very similar to the labeling
requirements from the Phase 1 rulemaking, though we would want to more
carefully consider the list of technologies that would allow for the
most effective inspection. We request comment on an appropriate list of
candidate technologies that would properly balance the need to limit
label content with the interest in providing the most useful
information for inspectors to confirm that vehicles have been properly
built. EPA is not proposing to modify the existing emission control
labels for vocational vehicles certified for MYs 2014-2020 (Phase 1)
CO2 standards.
    Under the agencies' existing authorities, manufacturers must
provide detailed build information for a specific vehicle upon our
request. Our expectation is that this information should be available
to us via email or other similar electronic communication on a same-day
basis, or within 24 hours of a request at most. We request comment on
any practical limitations in promptly providing this information. We
also request comment on approaches that would minimize burden for
manufacturers to respond to requests for vehicle build information and
would expedite an authorized compliance inspector's visual inspection.
For example, the agencies have started to explore ideas that would
provide inspectors with an electronic method to identify vehicles and
access on-line databases that would list all of the engine-specific and
vehicle-specific emissions control system information. We believe that
electronic and Internet technology exists today for using scan tools to
read a bar code or radio frequency identification tag affixed to a
vehicle that would then lead to secure on-line access to a database of
manufacturers' detailed vehicle and engine build information. Our
exploratory work on these ideas has raised questions about the level of
effort that would be required to develop, implement and maintain an
information technology system to provide inspectors real-time access to
this information. We have also considered questions about privacy and
data security. We request comment on the concept of electronic labels
and database access, including any available information on similar
systems that exist today and on burden estimates and approaches that
could address concerns about privacy and data security. Based on new
information that we receive, we may consider initiating a separate
rulemaking effort to propose and request comment on implementing such
an approach.
(b) End of Year Reports
    In the Phase 1 program, manufacturers participating in the ABT
program provided 90 day and 270 day reports to EPA and NHTSA after the
end of the model year. The agencies adopted two reports for the initial
program to help manufacturers become familiar with the reporting
process. For the HD Phase 2 program, the agencies propose to simplify
reporting such that

manufacturers would only be required to submit one end of the year
report 120 days after the end of the model year with the potential to
obtain approval for a delay up to 30 days. We welcome comment on this
proposed revision.
(c) Delegated Assembly
    The proposed standards for vocational vehicles are based on the
application of a wide range of technologies. Certifying vehicle
manufacturers manage their compliance demonstration to reflect this
range of technologies by describing their certified configurations in
the application for certification. In many cases, these technologies
are designed and assembled (or installed) directly by the certifying
vehicle manufacturer, which is typically the chassis manufacturer. In
these cases, it is straightforward to assign the responsibility to the
certifying vehicle manufacturer for ensuring that vehicles are in their
proper certified configuration when sold to the ultimate user. In Phase
1, the only vehicle technology available for certified vocational
vehicles was LRR tires. Because these are generally installed by the
chassis manufacturer, there would have been no need to rely on a second
stage manufacturer for purposes of certification.
    In Phase 2, the agencies are considering certain technologies where
the certifying vehicle manufacturer may want or need to rely on a
downstream manufacturing company (a secondary vehicle manufacturer) to
take steps to assemble or install certain components or technologies to
bring the vehicle into a certified configuration. A similar
relationship between manufacturers applies with aftertreatment devices
for certified engines. EPA has adopted ``delegated assembly''
provisions for engines at 40 CFR 1068.261 to describe how manufacturers
can share compliance responsibilities through these cooperative
assembly procedures.
    We are proposing to take a similar approach for vehicle-based GHG
standards in 40 CFR part 1037. The delegated assembly provisions as
proposed for GHG standards are focused on add-on features to reduce
aerodynamic drag, and on air conditioning systems. This may occur, for
example, if the certifying manufacturer sells a cab-complete chassis to
a secondary vehicle manufacturer, which in turn installs a box with the
appropriate aerodynamic accessories to reduce drag losses. To the
extent certifying manufacturers rely on secondary vehicle manufacturers
to bring the vehicle into a certified configuration, the following
provisions would apply:
     The certifying manufacturer would describe their approach
to delegated assembly in the application for certification.
     The certifying manufacturer would create installation
instructions to describe how the secondary vehicle manufacturer would
bring the vehicle into a certified configuration.
     The certifying manufacturer would have a contractual
agreement with each affected secondary vehicle manufacturer obligating
the secondary vehicle manufacturer to build each vehicle into a
certified configuration and to provide affidavits confirming proper
assembly procedures, and to provide information regarding deployment of
each type of technology (if there are technology options that relate to
different GEM input values).
    The delegated assembly provisions are most relevant to vocational
vehicles, but we are not proposing to limit these provisions to
vocational vehicles. Similarly, we expect that aerodynamic devices and
air conditioning systems are the most likely technologies for which
delegated assembly is appropriate, but we are not proposing to limit
the use of delegated assembly to these technologies.
    Secondary manufacturers (such as body builders) that build complete
vehicles from certified chassis are obligated to comply with the
emission-related installation instructions provided by the certifying
manufacturer. Secondary manufacturers that build complete vehicles from
exempted chassis are obligated to comply with all of the regulations.
    The draft regulations at 40 CFR 1037.621 describe further detailed
provisions related to delegated assembly. We request comment on all
aspects of these provisions. In particular, we request comment on how
the procedures should be applied more broadly or more narrowly for
specific technologies. We also request comment on any further
modifications that should be made to the delegated assembly provisions
to reflect the nature of manufacturing relationships or technologies
that are specific to greenhouse gas standards for heavy-duty highway
vehicles.
(d) Demonstrating Compliance With Proposed HFC Leakage Standards
    EPA is proposing requirements for vocational chassis manufacturers
to demonstrate reductions in direct emissions of HFC in their A/C
systems and components through a design-based method. The method for
calculating A/C leakage is the same as was adopted in Phase 1 for
tractors and HD pickups and vans. It is based closely on an industry-
consensus leakage scoring method, described below. This leakage scoring
method is correlated to experimentally-measured leakage rates from a
number of vehicles using the different available A/C components. As is
done currently for other HD vehicles, vocational chassis manufacturers
would choose from a menu of A/C equipment and components used in their
vehicles in order to establish leakage scores, to characterize their A/
C system leakage performance. The percent leakage per year would then
be calculated as this score divided by the system refrigerant capacity.
    Consistent with the light-duty rule and the Phase 1 program for
other HD vehicles, EPA is proposing a requirement that vocational
chassis manufacturers compare the components of a vehicle's A/C system
with a set of leakage-reduction technologies and actions that is based
closely on that developed through the Improved Mobile Air Conditioning