Bin II..............................................  ..............             70%             30%  ..............             70%             55%
    Bin III.............................................  ..............             30%             60%  ..............             30%             40%
    Bin IV..............................................  ..............  ..............             10%  ..............  ..............              5%
    Bin V...............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VI..............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VII.............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VIII............................................  ..............  ..............  ..............  ..............  ..............  ..............
        Average Delta CDA (m2) b........................             0.4             0.8             1.1             0.4             0.8             1.0
Trailer Tire Rolling Resistance:
    Baseline tires......................................             15%              5%              5%             15%              5%              5%
    Level 1 tires.......................................             85%             95%  ..............             85%             95%  ..............
    Level 2 tires.......................................  ..............  ..............             95%  ..............  ..............             95%
        Average CRR (kg/ton) b..........................             5.2             5.1             4.8             5.2             5.1             4.8
Tire Inflation System:
    ATI.................................................             85%             95%             95%             85%             95%             95%
        Average ATI Reduction (%) b.....................            1.3%            1.4%            1.4%            1.3%            1.4%            1.4%
Weight Reduction (lbs):
    Weight c............................................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
a The majority of short box trailers are 28 feet in length. We recognize that they are often operated in tandem, which limits the technologies that can
  be applied (for example, boat tails).
b Combines adoption rates with performance levels shown in Table IV-8.
c This set of adoption rates did not apply weight reduction to meet the proposed standards for these trailers.

(b) Derivation of the Standards for Alternative 4
    Similar to the proposed standards of Section IV. D. (3) (d), the
agencies applied the technology performance values from Table IV-22 and
Table IV-23 as GEM inputs to derive the proposed standards for each
subcategory.
    Table IV-24 shows the resulting standards for Alternative 4. Over
the three phases of the alternative, box trailers longer than 50 feet
would, on average, reduce their CO2 emissions and fuel
consumption by two percent, six percent and eight percent. Box trailers
50-foot and shorter would achieve reductions of two percent, three
percent, and four percent compared to the reference case. Partial-aero
box trailers would continue to be subject to the 2021 MY standards for
MY 2024 and later. The non-aero box and non-box trailers would meet the
same standards as shown in the proposed Alternative 3 and achieve the
same two and three percent benefits as shown in the proposed
alternative.

            Table IV-24--Trailer CO2 and Fuel Consumption Standards for Box Trailers in Alternative 4
----------------------------------------------------------------------------------------------------------------
                                   Subcategory                Dry van                    Refrigerated van
          Model year           ---------------------------------------------------------------------------------
                                     Length            Long            Short           Long            Short
----------------------------------------------------------------------------------------------------------------
2018-2020.....................  EPA Standard....              83             144              84             147
                                (CO2 Grams per
                                 Ton-Mile).
                                Voluntary NHTSA           8.1532         14.1454          8.2515         14.4401
                                 Standard.
                                (Gallons per
                                 1,000 Ton-Mile).
2021-2023.....................  EPA Standard....              80             142              81             145
                                (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard..          7.8585         13.9489          7.9568         14.2436
                                (Gallons per
                                 1,000 Ton-Mile).
2024+.........................  EPA Standard....              77             140              80             144
                                (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard..          7.5639         13.7525          7.8585         14.1454
                                (Gallons per
                                 1,000 Ton-Mile).
----------------------------------------------------------------------------------------------------------------

(c) Costs Associated With Alternative 4
    A summary of the technology costs is included in Table IV-25 to
Table IV-27for MYs 2018, 2021 and 2024, with additional details
available in the draft RIA Chapter 2.12. Costs shown in the following
tables are for the specific model year indicated and are incremental to
the average reference case costs, which includes some level of adoption
of these technologies as shown in Table IV-10. Therefore, the
technology costs in the following tables reflect the average cost
expected for each of the indicated trailer classes. Note that these
costs do not represent actual costs for the individual components
because some fraction of the component costs has been subtracted to
reflect some use of these components in the reference case. For more on
the estimated technology costs exclusive of adoption rates, refer to
Chapter 2.12 of the draft RIA. These costs include indirect costs via
markups and reflect lower costs over time due to 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
the draft RIA.

           Table IV-25--Trailer Technology Incremental Costs in the 2018 Model Year for Alternative 4
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                    53-foot dry    refrigerated     28-foot dry   Non-aero & non-
                                                        van             van             van             box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................            $285            $285              $0              $0
Tires...........................................              65              65              78             185
Tire inflation system...........................             239             239             435             683
                                                 ---------------------------------------------------------------
    Total.......................................             588             588             514             868
----------------------------------------------------------------------------------------------------------------

           Table IV-26--Trailer Technology Incremental Costs in the 2021 Model Year for Alternative 4
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                    53-foot dry    refrigerated     28-foot dry   Non-aero & non-
                                                        van             van             van             box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................            $908            $908            $641              $0
Tires...........................................              65              65              79             175
Tire inflation system...........................             234             234             426             632
                                                 ---------------------------------------------------------------
    Total.......................................           1,207           1,207           1,146             807
----------------------------------------------------------------------------------------------------------------

           Table IV-27--Trailer Technology Incremental Costs in the 2024 Model Year for Alternative 4
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                    53-foot dry    refrigerated     28-foot dry   Non-aero & non-
                                                        van             van             van             box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................           1,223           1,090             816               0
Tires...........................................              61              61              76             160
Tire inflation system...........................             220             220             412             578
                                                 ---------------------------------------------------------------
    Total.......................................           1,504           1,371           1,304             739
----------------------------------------------------------------------------------------------------------------

    The agencies believe Alternative 4 has the potential to be the
maximum feasible and appropriate alternative. However, based on the
evidence currently before us, EPA and NHTSA have outstanding questions
regarding relative risks and benefits of Alternative 4 due to the
timeframe envisioned by that alternative. As discussed earlier, the
ability for manufacturers in this industry to broadly take the
necessary technical steps while becoming familiar with first-time
regulatory responsibilities may be significantly limited with three
fewer years of lead-time. As reinforced in the SBAR Panel Report, this
challenge would not be equal across the industry, often falling more
heavily on smaller trailer manufacturers.
    The agencies request comment on the feasibility and costs for
trailer manufacturers to achieve the Alternative 4 standards by
applying advanced aerodynamic technologies with three years less lead-
time than Alternative 3 would provide. The agencies also request
comment on particular burdens that these aggressive adoption rates
could have on small business trailer manufacturers.

F. Trailer Standards: Compliance and Flexibilities

    Under the proposed structure, trailer manufacturers would be
required to obtain a certificate of conformity from EPA before
introducing into commerce new trailers subject to the proposed new
trailer CO2 and fuel consumption standards. See CAA section
206(a). The certification process the agencies are proposing for
trailer manufacturers is very similar in its basic structure to the
process for the tractor program. This structure involves pre-
certification activities, the certification application and its
approval, and end-of-year reporting.
    In this section, the agencies first describe how we developed
compliance equations based on the GEM vehicle simulation tool and the
general certification process, followed by a discussion of the proposed
test procedures for measuring the performance of tires and aerodynamic
technologies and how manufacturers would apply test results toward
compliance and certification. The section closes with discussions of
several other proposed certification and compliance provisions as well
as proposed provisions to provide manufacturers with compliance
flexibility.
(1) Trailer Compliance Using a GEM-Based Equation
    The agencies are committed to introducing a compliance program for
trailer manufacturers that is straightforward, technically robust,
transparent, and that minimizes new administrative burdens on the
industry. As described earlier in this section and in Chapter 4 of the
draft RIA, GEM is a customized vehicle simulation model that EPA
developed for the Phase 1 program to relate measured aerodynamic and
tire performance values, as well as other parameters, to CO2
and fuel consumption without performing full-vehicle testing. As with
the Phase 1 and proposed Phase 2 tractor and vocational vehicle
programs, the proposed trailer program uses GEM in evaluating emissions
and fuel consumption in developing the proposed standards. However,
unlike the tractor and vocational vehicle programs, we are not
proposing to use GEM directly to demonstrate compliance with the
trailer standards. Instead, we have developed an equation based on GEM
that calculates CO2 and fuel consumption from performance
inputs, but without running the model.
    For the proposed trailer program, the trailer characteristics that
a manufacturer would supply to the equation are aerodynamic
improvements (i.e., a change in the aerodynamic drag area, delta
CDA), tire rolling resistance (i.e., coefficient of rolling
resistance, CRR), the presence of an automatic tire
inflation (ATI) system, and the use of light-weight components from a
pre-determined list. The use of the equation would quantify the overall
performance of the trailer in terms of CO2 emissions and
fuel consumption on a per ton-mile basis.
    Chapter 2.10.6 of the draft RIA provides a full a description of
the development and evaluation of the equation proposed for trailer
compliance. Equation IV-1 is a single linear regression curve that can
be used for all box trailers in this proposal. Unique constant values,
C1 through C4, are applied for each of the
trailer subcategories as shown in Table IV-28. Constant C5
is equal to 0.985 for any trailer that installs an ATI system
(accounting for the 1.5 percent reduction given for use of ATI) or 1.0
for trailers without ATI systems. This equation was found to accurately
reproduce the results of GEM for each of the four box van subcategories
and the agencies are proposing that trailer manufacturers use Equation
IV-1 when calculating CO2 for compliance. Manufacturers
would use a conversion of 10,180 grams of CO2 per gallon of
diesel to calculate the corresponding fuel consumption values for
compliance with NHTSA's regulations. See 40 CFR 1037.515 and 49 CFR
535.6.

y = [C1 + C2[middot](TRRL) +
C3[middot]([Delta]CDA) +
C4[middot](WR)][middot]C5 (IV-1)

                        Table IV-28--Constants for GEM-Based Trailer Compliance Equation
----------------------------------------------------------------------------------------------------------------
               Trailer subcategory                      C1              C2              C3              C4
----------------------------------------------------------------------------------------------------------------
Long Dry Van....................................            77.4             1.7            -6.1          -0.001
Long Refrigerated Van...........................            78.3             1.8            -6.0          -0.001
Short Dry Van...................................           134.0             2.2           -10.5          -0.003
Short Refrigerated Van..........................           136.3             2.4           -10.3          -0.003
----------------------------------------------------------------------------------------------------------------

    The constants for long vans apply for all dry or refrigerated vans
longer than 50-feet and the constants for short vans apply for all dry
or refrigerated vans 50-feet and shorter. These long and short van
constants are based on GEM-simulated tractors pulling 53-foot and solo
28-foot trailers, respectively. As a result, we are proposing that
aerodynamic testing to obtain a trailer's performance parameters for
Equation IV-1 be performed using consistent trailer sizes (i.e., all
lengths of short vans be tested as a solo 28-foot van, and all lengths
of long vans be tested as a 53-foot van). More information about
aerodynamic testing is provided in Section IV. F. (3).
(2) General Certification Process
    Under the proposed process for certification, trailer manufacturers
would be required to apply to EPA for certification and would provide
performance test data (see 40 CFR 1037.205) in their applications.\242\
A

staff member from EPA's Compliance Division (in the Office of
Transportation and Air Quality) would be assigned to each trailer
manufacturer to help them through the compliance process. Although not
required, we recommend that manufacturers arrange to meet with the
agencies to discuss compliance plans and obtain any preliminary
approvals (e.g., appropriate test methods) before applying for
certification.
---------------------------------------------------------------------------

    \242\ As with the tractor program, manufacturers would submit
their applications to EPA, which would then share them with NHTSA.
Obtaining an approved certificate of conformity from EPA is the
first step in complying with the NHTSA program.
---------------------------------------------------------------------------

    Trailer manufacturers would submit their applications through the
EPA VERIFY electronic database, and EPA would issue certificates based
on the information provided. At the end of the model year, trailer
manufacturers would submit an end-of-year report to the agencies to
complete their annual obligations.
    The proposed EPA certification provisions also contain provisions
for applying to the NHTSA program. EPA and NHTSA would coordinate on
any enforcement action required.
(a) Preliminary Considerations for Compliance
    Prior to submitting an application for a certificate, a
manufacturer would choose the technologies they plan to offer their
customers, obtain performance information for these technologies, and
identify any trailers in their production line that qualify for
exclusion from the program.\243\ Manufacturers that choose to perform
aerodynamic or tire testing would obtain approval of test methods and
perform preliminary testing as needed. During this time, the
manufacturer would also decide the strategy they intend to use for
compliance by identifying ``families'' for the trailers they produce. A
family is a grouping of similar products that would all be subject to
the same standard and covered by a single certificate.
---------------------------------------------------------------------------

    \243\ Trailers that meet the qualifications for exclusion do not
require a certificate of conformity and manufacturers do not have to
submit an application to EPA for these trailers.
---------------------------------------------------------------------------

    At its simplest, the program would allow all products in each of
the trailer subcategories to be certified as separate families. That
is, long box dry vans, short box dry vans, long refrigerated vans,
short refrigerated vans, non-box trailers, partial-aero trailers (long
and short box, dry and refrigerated vans), and non-aero trailers, could
each be certified as separate trailer families. If a manufacturer
chooses this approach, all products within a family would need to meet
or do better than the standards for that trailer subcategory. This is
not to say that, for example, every long box dry van model would need
to have identical technologies like skirts, tires, and tire inflation
systems, but that every model in that family would need to have a
combination of technologies that had performance representative of
testing demonstrated for that family. (Because the manufacturer would
not be using averaging provisions, a trailer that ``over-complied''
could not offset a trailer that did not meet that family's emission
limit).
    If a trailer manufacturer wishes to take advantage of the proposed
averaging provisions, it could divide the trailer models in each of the
standard box trailer categories (i.e., not including the non-box
trailer or non-aero box trailer categories\244\) into subfamilies. Each
subfamily could be a grouping of trailers that have with similar
performance levels, even if they use different technologies. We call
the performance levels for each subfamily as ``Family Emission Limits''
(FELs). A long box dry van manufacturer could choose, for example, to
create two or more subfamilies in its long box dry van family. Trailers
in one or more of these subfamilies could be allowed to under-comply
with the standard (e.g., if the manufacturer chose not to apply ATI or
chose tires with higher rolling resistance levels) as long as the
performance of the other subfamilies over-comply with the standard
(e.g., if the manufacturer applied higher-performing skirts) such that
the average of all of the subfamilies' FELs met or did better than the
stringency for that family on a production-weighted basis. Section
IV.F.6.a below further discusses how the proposed averaging program
would function for any such trailer subfamilies.
---------------------------------------------------------------------------

    \244\ The agencies are proposing that manufacturers implement
100 percent of their non-box and special purpose box trailers with
automatic tire inflation systems and tires meeting the specified
rolling resistance levels. As a result, averaging provisions do not
apply to these trailer subcategories.
---------------------------------------------------------------------------

b) Submitting a Certification Application and Request for a Certificate
to EPA
    Once the preliminary steps are completed, the manufacturer can
prepare and submit applications to EPA for certificate of conformity
for each of its trailer families. The contents of the application are
specified in 40 CFR 1037.205, though not all items listed in the
regulation are applicable to each trailer manufacturer.
    For the early years of the program (i.e., 2018 through 2020), the
application must specify whether the trailer manufacturer is opting
into the NHTSA voluntary program to ensure the information is
transferred between the agencies. It must also include a description of
the emission controls that a manufacturer intends to offer. These
emission controls could include aerodynamic features, tire models, tire
inflation systems or components that qualify for weight reduction.
Basic information about labeling, warranty, and recommended maintenance
should also be included the application (see Section IV.F.5 for more
information).
    The manufacturer would also provide a summary of the plans to
comply with the standard. This information would include a description
of the trailer family and subfamilies (if applicable) covered by the
certificate and projected sales of its products. Manufacturers that do
not participate in averaging would include information on the lowest
level of CO2 and fuel consumption performance offered in the
trailer family. Manufacturers that choose to average within their
families would include performance information for the projected
highest production trailer configuration, as well as the lowest and the
highest performing configurations within that trailer family.
(c) End-of-Year Obligations
    After the end of each year, all manufacturers would need to submit
a report to the agencies presenting production-related data for that
year (see 40 CFR 1037.250 and 49 CFR 535.8). In addition, manufacturers
participating in the averaging program would submit an end-of-year
report containing both emissions and fuel consumption information for
both agencies. This report would include the year's final compliance
data (as calculated using the compliance equation) and actual sales in
order to demonstrate that the trailers either met the standards for
that year or that the manufacturer generated a deficit to be reconciled
within the next three years under the averaging provisions (see 40 CFR
1037.730, 40 CFR 1037.745, and 49 CFR 535.7). All certifying
manufacturers would need to maintain records of all the data and
information required to be supplied to EPA and NHTSA for eight years.
(3) Trailer Certification Test Protocols
    The Clean Air Act specifies that compliance with emission standards
for motor vehicles be demonstrated using emission test data (see CAA
section 206(a) and (b)). The Act does not require the use of specific
technologies or designs. The agencies are proposing that the compliance
equation shown in

Section IV. F. (1) function as the official ``test procedure'' for
quantifying CO2 and fuel consumption performance for trailer
compliance and certification (as opposed to GEM, which serves this
function in the tractor and vocational vehicle programs). Manufacturers
would insert performance information from the trailer technologies
applied into the equation in order to calculate their impact on overall
trailer performance. The agencies are proposing to assign performance
levels to ATI systems and specific weight reduction values to pre-
determined component substitutions. Aerodynamic and tire rolling
resistance performance would be obtained by the trailer manufacturers.
The following sections describe the approved performance tests for tire
rolling resistance and aerodynamic drag. Non-box and non-aero box
trailers have tire requirements only. Manufacturers of these trailers
will only need to obtain results from the tire performance tests. Long
and short box trailers are expected to use aerodynamic and tire
technologies to meet the proposed standards and will need to obtain
test results from both procedures. See generally proposed 40 CFR part
1037, subpart F, for full description of the proposed performance
tests, and see in particular proposed section 40 CFR 1037.515.
(a) Trailer Tire Performance Testing
    Under Phase 1, tractor and vocational chassis manufacturers are
required to input the tire rolling resistance coefficient into GEM and
the agencies adopted the provisions in ISO 28580:2009(E) \245\ to
determine the rolling resistance of tires. As described in 40 CFR
1037.520(c), this measured value, expressed as CRR, is
required to be the result of at least three repeat measurements of
three different tires of a given design, giving a total of at least
nine data points. Manufacturers specify a CRR value for GEM
that may not be lower than the average of these nine results. Tire
rolling resistance may be determined by either the vehicle or tire
manufacturer. In the latter case, the tire manufacturer would provide a
signed statement confirming that it conducted testing in accordance
with this part.
---------------------------------------------------------------------------

    \245\ See http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=44770.
---------------------------------------------------------------------------

    Similar to the tractor program, we propose to extend the Phase 1
testing provisions for tire rolling resistance to apply to the Phase 2
box trailer program, only without requiring the use of GEM. The average
rolling resistance value obtained from this test would be used to
specify the tire rolling resistance level (TRRL) for the trailer tires
in the compliance equation. Based on the current practice for tractors,
we expect the trailer manufacturers to obtain these data from tire
manufacturers. We welcome comments regarding the proposed tire testing
provisions as they relate to the proposed trailer program.
    For non-box trailers, the agencies are proposing to use the same
test methods to evaluate tires, but are proposing to apply a single
threshold standard instead of inputting the rolling resistance value
into the GEM equation. Manufacturers of non-box trailers would comply
with the rolling resistance standard by using tires with rolling
resistance below the threshold. From the perspective of the trailer
manufacturer, this would be equivalent to a design standard for the
trailers, even though the standard would be expressed as a performance
standard for the tires.
    The agencies are considering adopting a program for tire
manufacturers similar to the provision described in Section IV. F. (3)
(b)(iv) for aerodynamic device manufacturers. For aerodynamic devices,
the agencies are proposing to allow device manufacturers to seek
preliminary approval of the performance of their devices. Device
manufacturers would perform the required testing of their device and
submit the performance results directly to EPA. We are requesting
comment on a similar provision for tires. Tire manufacturers could
submit their test data directly to EPA to show they meet the rolling
resistance requirements, and trailer manufacturers that choose to use
approved tires would merely indicate that in their the certification
applications.
    EPA is also considering adopting regulatory text addressing
obligations for tire manufacturers. We note that CAA section 207(c)(1)
requires ``the manufacturer'' to remedy certain in-use problems and
does not limit this responsibility to certificate holders. The remedy
process is generally called recall, and the regulations for this
process are in 40 CFR part 1068, subpart F. In the case of in-use
problems with trailer tires, EPA is requesting comment on adding
regulatory text that would explicitly apply these provisions to tire
manufacturers. In other words, if EPA determines that tires on
certified trailers do not conform to the regulations in actual use,
should EPA require the tire manufacturer to recall and replace the
nonconforming tires? \246\
---------------------------------------------------------------------------

    \246\ EPA is considering such a requirement for trailer tire
manufacturers, but not at this time for manufacturers of other
heavy-duty vehicle components. This is because, for the trailer
sector, we believe that the small business trailer manufacturers
that make up a large fraction of companies in this industry could be
uniquely challenged if they needed to recall trailers to replace
tires.
---------------------------------------------------------------------------

(b) Trailer Aerodynamic Performance Testing
    Our proposed trailer aerodynamic test procedures are based on the
current and proposed tractor procedures for testing aerodynamic control
devices, including coastdown, constant speed, wind tunnel, and
computational fluid dynamics (CFD) modeling. The purpose of the tests
is to establish an estimate of the aerodynamic drag experienced by a
tractor-trailer vehicle in real-world operation. In the tractor
program, the resulting CdA value represents the aerodynamic drag of a
tested tractor assumed to be pulling a specified standard trailer. In
the proposed trailer program, the CDA value used in the
compliance equation would represent the tested trailer pulled by a
standard tractor.
    To minimize the number of tests required, the agencies are
proposing that devices for long trailers be evaluated based on 53-foot
trailers, and that devices for short trailers be evaluated based on 28-
foot trailers. Details of the test procedures can be found in 40 CFR
1037.525 and a discussion of EPA's aerodynamic testing program as it
relates to the proposed trailer program are provided in the draft RIA
Chapter 3.2. The following sections outline the testing requirements
proposed for the long term trailer program, as well as simpler testing
provisions that would apply in the nearer term.
(i) A to B Testing for Trailer Aerodynamic Performance
    A key difference between the proposed tractor and trailer programs
is that while the tractor procedures provide a direct measurement of an
absolute CDA value for each tractor model, the agencies
expect a majority of the aerodynamic improvements for trailers will be
accomplished by adding bolt-on technologies. As a result, we are
proposing to evaluate the aerodynamic improvements for trailers by
measuring a change in CDA (delta CDA) relative to
a baseline. Specifically, we propose that the trailer tests be
performed as ``A to B'' tests, comparing the aerodynamic performance of
a tractor-trailer without a trailer aerodynamic device to one with the
device installed. See Draft RIA Chapter 2.10 for more information on
this approach.
    As mentioned in Section IV. F. (1) that is consistent with the
compliance

equations. See 40 CFR 1037.525 and 49 CFR 535.6. We believe that most
trailers longer than 50 feet with comparable technologies would perform
similarly in aerodynamic testing. We also recognize that devices used
on some lengths of trailers in the short-van category may perform
differently than those devices perform when used on a representative
28-foot test trailer.
    The agencies are proposing that manufacturers have some flexibility
in the devices (or packages of devices) that they use with box vans
that have lengths different than those of the trailers on which the
devices/packages were tested (i.e., trailers not 53 or 28 feet long).
In such situations, a manufacturer could use devices that they believe
would be more appropriate for the length of the trailer they are
producing, consistent with good engineering judgement. For example,
they could use longer or shorter side skirts than those tested on 53-
or 28-foot trailers. No additional testing would be required in order
to validate the appropriateness of using the alternate devices on these
trailers.
    On average, we believe that testing of a device on a 28-foot test
trailer would provide a conservative evaluation of the performance of
that device on other lengths of short box trailers. We believe that the
proposed compliance approach would effectively represent the
performance of such devices on the majority of short van trailers, yet
would limit the number of trailers a manufacturer would need to track
and evaluate. We request comment, including data where possible, on
additional approaches that could be used to address this issue of
varying performance for devices across the range of short van lengths.
Commenters supporting an allowance or requirement to test devices on
short van trailers of other lengths than 28 feet are encouraged to also
address how the agencies should consider such a provision in setting
the levels of the standards, as well as how any additional compliance
complexity would be justified.
    The agencies note that it was relatively straightforward in Phase 1
to establish a standard trailer with enough specificity to ensure
consistent testing of tractors, since there are relatively small
differences in aerodynamic performance of base-model dry van trailers.
However, as discussed in Chapter 2.10 of the draft RIA, small
differences in tractor design can have a significant impact on overall
tractor-trailer aerodynamic performance. An advantage of an A to B test
approach for trailers is that many of the differences in tractor design
are canceled-out, which allows a variety of standard tractors to be
used in testing without compromising the evaluation of the trailer
aerodynamic technology. Thus, the relative approach does not require
the agencies to precisely specify a standard tractor, nor does it
require trailer manufacturers to purchase, modify or retain a specific
tractor model in order to evaluate their trailers.
    In essence, an A to B test is a set of tests: one test of a
baseline tractor-trailer with zero trailer aerodynamic technologies
(A), and one test that includes the aerodynamic devices to be tested
(B). However, because an A test would relate to a B test only with
respect to the test method and the test trailer length, one A test
could be used for many different B tests. This type of testing would
result in a delta CDA value instead of an absolute
CDA value. For the trailer program, the vehicle
configuration in the A test would include a standard tractor that meets
specified characteristics,\247\ and a manufacturer's baseline trailer
with no aerodynamic improvements. The entity conducting the testing
(e.g., the trailer manufacturer or the trailer aerodynamic device
manufacturer, as discussed below) would perform the test for this
configuration according to the procedures in 40 CFR 1037.525 and repeat
the test for the B configuration, which includes the trailer
aerodynamic package/device(s) being tested. The delta CDA
value for that trailer with that device would be the difference between
the CDA values obtained in the A and B tests.
---------------------------------------------------------------------------

    \247\ As explained in Section IV. F. (3) (b)(ii), the standard
tractor in GEM consists of a high roof sleeper cab for box trailers
longer than 50 feet and a high roof day cab for box trailers 50 feet
and shorter.
---------------------------------------------------------------------------

    In the event that a trailer manufacturer makes major changes to the
aerodynamic design of its trailer in lieu of installing add-on devices,
trailer manufacturers would use the same baseline trailer for the A
configuration as would be used for bolt-on features. In both cases, the
baseline trailer would be a manufacturer's standard box trailer. Thus,
the manufacturer of a redesigned trailer would get full credit for any
aerodynamic improvements it made. We request comment on this issue. In
addition, we request comment on how the program could handle a
situation in which a manufacturer made aerodynamic design changes to a
trailer between 28 and 50 feet, which as proposed could only be
compared to a 28-foot standard trailer.
    The agencies are proposing to determine the delta CDA
for trailer aerodynamics using the zero-yaw (or head-on wind) values.
The agencies are not proposing a reference method (i.e., the coastdown
procedure in the tractor program). Instead, we are proposing to allow
manufacturers to perform any of the proposed test procedures to
establish a delta CDA. Since the proposed coastdown and
constant speed procedures include wind restrictions, we are proposing
to only accept the zero-yaw values from aerodynamic evaluation
techniques that are capable of measuring drag at multiple yaw angles
(e.g., wind tunnels and CFD) to allow cross-method comparison and
certification. The agencies welcome comment on the pros and cons of
exclusive use of zero-yaw data from trailer aerodynamic compliance
testing. We recognize that the benefits of aerodynamic devices can be
higher when measured considering wind from other yaw angles. We request
comment on the possibility of allowing manufacturers to use wind-
averaged results for compliance if they choose to test using procedures
that provide wind-averaged values. Chapter 2.10 of the draft RIA
compares zero-yaw and wind-averaged results from EPA's wind tunnel
testing. We request that commenters provide test data to support any
preference for compliance test results. We also request comments on
strategies that could be used to maintain consistency with other
methods that cannot provide wind-averaged results.
(ii) Standard Tractor for Aerodynamic Testing in the Proposed Trailer
Program
    We propose that the proposed compliance equation, based on GEM, be
used to determine compliance with the trailer standards. Our discussion
of the feasibility of our proposed standards (Section IV. D. (3) (a))
includes a description of the tractor-trailer vehicle used in GEM. We
recognize the impact of the tractor and want to maintain consistency
with GEM, but for the trailer program it is not necessary to address
all aspects (e.g., the engine) of the tractor, because, as explained
above, the impact of many of its features will be canceled-out with the
use of an A to B test strategy. However, some aerodynamic design
features of the tractor can influence the performance of trailer
aerodynamic technologies and we want to ensure a level of consistency
between tests of different trailer manufacturers.
    The agencies believe the A to B test strategy would reduce the
degree of precision with which the standard tractor needs to be
specified. Instead of identifying a specific make and model of a
tractor to be used over the entire duration of the program, the
agencies

would instead identify key characteristics of a standard tractor. EPA's
trailer testing program investigated the impact of tractor aerodynamics
on the performance of trailer aerodynamic technologies, as mentioned in
Chapter 2.10 of the draft RIA. In order to maintain a minimal level of
performance, we are proposing that tractors used in trailer aerodynamic
tests meet Phase 2 Bin III or better tractor requirements (see Section
III.D.). We believe the majority of tractors in the U.S. trucking fleet
will be Bin III or better in the timeframe of this rulemaking, and
trailer manufacturers have the option to choose higher-performing
tractors in later years as tractor technology improves. The standard
tractor for long-box trailers is a Class 8 high-roof sleeper cab. The
standard tractor for short box trailers is a Class 8 high roof day cab.
Trailer manufacturers are free to choose any standard tractor that
meets these criteria in their aerodynamic performance testing. See 40
CFR 1037.501.
(iii) Bins for Aerodynamic Performance
    As mentioned in Section IV. D. (1) (a), the agencies are proposing
aerodynamic bins to account for testing variability and to provide
consistency in the performance values used for compliance. These bins
were developed in terms of delta CDA ranges, and designed to
be broad enough to cover the range of uncertainty seen in our
aerodynamic testing program in terms of test-to-test variability as
well as variability due to differences in test method, tractor models,
trailer models and device models.
    As discussed in Chapter 2.10 of the draft RIA, measured drag
coefficients and drag areas vary depending on the test method used. In
general, values measured using wind tunnels and CFD tend to be lower
than values measured using the coastdown method. The Phase 1 and
proposed Phase 2 tractor program use coastdown testing as the reference
test method, and the agencies require tractor manufacturers to perform
at least one test using that method to establish a correction factor
(called ``Falt,aero'') to apply to any of the alternative
test methods. For simplicity, the agencies are not proposing a similar
approach for trailers. We believe that the size of the bins and the use
of change in CDA (as opposed to absolute values) would
minimize the significance of this variability. However, we recognize
that this could be a problem in instances where a manufacturer using a
method other than coastdown produces a trailer with performance near
the upper end of a bin. In such cases, it is possible that adjusting
for methodological differences using a Falt,aero would allow
the manufacturer to achieve a more stringent bin.
    We request comment on the proposed approach for evaluating
performance of trailers and establishing bins for trailer compliance.
We specifically request that commenters address the need for an
aerodynamic reference test for trailer performance or additional
strategies for normalizing test methods. For example, would it be
appropriate to allow all manufacturers using wind tunnel or CFD methods
to apply an assigned Falt,aero of 1.10, or another value, to
their results?

   Table IV-29--Aerodynamic Bins Used To Determine Inputs for Trailer
                              Certification
------------------------------------------------------------------------
                                                               Average
                                                              delta CDA
   Delta CDA measured in testing               Bin            input for
                                                                 gem
------------------------------------------------------------------------
0.09...............................  Bin I.................          0.0
0.10-0.19..........................  Bin II................          0.1
0.20-0.39..........................  Bin III...............          0.3
0.40-0.59..........................  Bin IV................          0.5
0.60-0.79..........................  Bin V.................          0.7
0.80-1.19..........................  Bin VI................          1.0
1.20-1.59..........................  Bin VII...............          1.4
[gteqt] 1.6........................  Bin VIII..............          1.8
------------------------------------------------------------------------

    A manufacturer that wished to perform testing would first identify
a standard tractor (according to 40 CFR 1037.525) and a representative
baseline trailer with no aerodynamic features, then perform the A to B
tests with and without aerodynamic devices and obtain a delta
CDA value. The manufacturer would use Table IV-29 to
determine the appropriate bin based on their delta CDA. Each
bin has a corresponding average delta CDA value which is the
value manufacturers insert into the compliance equation.
(iv) Aerodynamic Device Testing Alternative
    The agencies recognize that much of the trailer manufacturing
industry may have little experience with aerodynamic performance
testing. As such, we are proposing an alternative compliance option
that we believe will minimize the testing burden for trailer
manufacturers, meet the requirements of the Clean Air Act and of EISA,
and provide reasonable assurance that the anticipated CO2
and fuel consumption benefits of the program will be realized in real-
world operation.
    The agencies are proposing to allow trailer aerodynamic device
manufacturers to seek preliminary approval of the performance of their
devices (or combinations of devices) based on the same performance
tests described previously in Section IV. F. (3) (b)(i). Device
manufacturers would perform the required A to B testing of their
device(s) on a trailer that meets the requirements specified in 40 CFR
1037.211 and 1037.525 and submit the performance results, in terms of
delta CDA, directly to EPA.\248\ Trailer manufacturers could
then choose to use these devices and apply their performance levels in
the certification application for their trailer families. This approach
would provide an opportunity for trailer manufacturers to choose
technologies with pre-approved test data for installation on their new
trailers without performing their own aerodynamic testing. We note that
this proposed testing alternative is consistent with recommendations of
the SBAR Panel. The Panel Report is summarized below in Section XV.D.
---------------------------------------------------------------------------

    \248\ Note that in the event a device manufacturer chooses to
submit such data to EPA, it could incur liability for causing a
regulated entity to commit a prohibited act. See 40 CFR 1068.101(c).
This same potential liability exists with respect to information
provided by a device manufacturer directly to a trailer
manufacturer.
---------------------------------------------------------------------------

    If trailer manufacturers wish to use multiple devices with pre-
approved test data, the proposed program provides a process for
combining the effects of multiple devices to determine an appropriate
delta CDA value for compliance. More specifically, such
manufacturers would fully count the technology with largest delta
CDA value, discount the second by 10 percent, and discount
each of the remaining additional technologies by 20 percent.\249\ This
discounting would acknowledge the complex interactions among individual
aerodynamic devices and would provide a conservative value for the
impact of the combined devices. For example, a manufacturer applying
three separately tested devices with delta CDA values of
0.40, 0.30, and 0.10 would calculate the combined delta CDA
as:
---------------------------------------------------------------------------

    \249\ A trailer manufacturer would need to use good engineering
judgement in combining devices for compliance in order to avoid
combinations that are not intended to work together (e.g., both a
side skirt and an under-body device).

---------------------------------------------------------------------------
Delta CDA = 0.40 + 0.90*0.30 + 0.80*0.10 = 0.75 m\2\

    In addition, the agencies believe that discounting the delta
CDA values of individually-tested devices used as a
combination would provide a modest incentive for trailer or device
manufacturers to test and get EPA pre-approval of the combination as an
aerodynamic system for compliance. We propose that device manufacturers
be

allowed to test and receive EPA pre-approval for combinations of
devices, and that trailer manufacturers that wish to use those specific
combinations be allowed to use the results from the tests of the
combined devices.
    The agencies note that many of the largest box trailer
manufacturers are already performing aerodynamic test procedures to
some extent, and the agencies expect other box trailer manufacturers
will increasingly be capable of performing these tests as the program
progresses.
    The proposed alternative testing approach is intended to allow
trailer manufacturers to focus on and become familiar with the
certification process in the early years of the program and, if they
wish, begin to perform testing in the later years, when it may be more
appropriate for their individual companies. This approach would not
preclude trailer manufacturers from performing their own testing at any
time, even if the technologies they wish to install are already pre-
approved. For example, a manufacturer that believed a specific trailer
actually performed in a more synergistic manner with a given device
than the device's pre-approved delta CDA value suggested
could perform its own testing and submit the results to EPA for
certification. The process to obtain approval is outlined in the
proposed 40 CFR 1037.211.
(4) Use of the Compliance Equation for Trailer Compliance
    The agencies are proposing standards for non-box and non-aero box
trailers requiring the use of tires with rolling resistance levels at
or below a threshold, and on ATI systems. As part of their
certification application, manufacturers of these trailers would submit
their tire rolling resistance levels and a description of their ATI
system(s) to EPA. As long as the trailer manufacturer certifies that
they will install the appropriate tires and ATI systems on all of their
trailers, the agencies do not believe it is necessary to require these
trailer manufacturers to use the equation and report the results of the
model to the agencies to demonstrate compliance.
    Box trailer manufacturers who apply more than tire technologies to
meet the standards would use the compliance equation to combine the
effects of these technologies and quantify the overall performance of
the vehicle to demonstrate compliance. Trailer manufacturers would
obtain delta CDA and tire rolling resistance values from
testing (either from their own testing or testing performed by another
entity as described previously) and note if they installed a qualifying
automatic tire inflation system or made a component substitution that
qualifies for weight reduction. Manufacturers would directly apply the
delta CDA and TRRL values into the equation, which would
also recognize the use of an ATI system, applying a 1.5 percent
reduction in CO2 and fuel consumption. Qualifying components
for weight reduction can be found in 40 CFR 1037.515(d). Manufacturers
that substitute one or more of these components on their box trailers
would sum the weight reductions assigned to each component and enter
that total into the equation. The equation would also account for the
use of weight-reducing components, assigning one-third of that reduced
weight to increase the payload and the remaining weight reduction to
reduce the overall weight of the assumed vehicle.
    For this proposal, we are requiring that the equation be used if
the manufacturer is to take advantage of the agencies' proposed
averaging provisions. Prior to submitting a certificate application,
manufacturers would decide which technologies to make available for
their customers and use the equation to determine the range performance
of the packages they will offer. Manufacturers would supply these
results from the equation in their certificate application and those
manufacturers that wish to perform averaging would continue to
calculate emissions (and fuel consumption) with the equation throughout
the model year and keep records of the results for each trailer package
sold. As described in Section IV.F.2.c above, at the end of the year,
manufacturers would submit two reports. One report would include their
production volumes for each configuration. The second report, required
for manufacturers using averaging, would summarize the families and
subfamilies, and CO2 emissions and fuel consumption results
from the equation for all of the trailer configurations they
build.\250\
---------------------------------------------------------------------------

    \250\ We are not proposing to allow manufacturers to ``bank''
credits to the following year if a manufacturer over-complies on
average for a given model year. We are proposing to allow
manufacturers to generate temporary deficits if they under-comply on
average. These deficits would need to be resolved within three model
years. See Section IV.F.7.a below and 40 CFR 1037.250, 40 CFR
1037.730, and 49 CFR 535.7.
---------------------------------------------------------------------------

    Box trailer manufacturers that do not participate in averaging
would also use the compliance equation to ensure that all of the
trailer configurations they offer would meet the standard for the given
model year. These calculations using the equation could be performed by
the manufacturer prior to submitting a certificate application, but it
is not necessary for the manufacturer to continue to calculate
emissions and fuel consumption throughout the model year unless a new
technology package is offered. These manufacturers would submit a
single end-of-year report that would include their production volumes
and confirmation that all of their trailers applied the technology
packages outlined in their application.
(5) Additional Certification and Compliance Provisions
(a) Trailer Useful Life
    Section 202(a)(1) of the CAA specifies that EPA is to propose
emission standards that are applicable for the ``useful life'' of the
vehicle. NHTSA also proposes to adopt EPA's useful life requirements
for trailers to ensure manufacturers consider in the design process the
need for fuel efficiency standards to apply for the same duration and
mileage as EPA standards. Based on our own research and discussions
with trailer manufacturers, EPA and NHTSA are proposing a regulatory
useful life value for trailers of 10 years. This useful life represents
the average duration of the initial use of trailers, before they are
moved into less rigorous (e.g., limited use or storage) duty. We note
that the useful life value is 10 years for other heavy-duty vehicles.
However, unlike the other vehicles, we are not proposing to set a mile
value for trailers because we do not require odometers for trailers.
    Thus, we propose that trailer manufacturers be responsible for
meeting the CO2 emissions and fuel consumption standards for
10 years after the trailer is produced. We believe that manufacturers
would be able to demonstrate at certification that their trailers will
comply for the useful life of the trailers without durability testing.
The aerodynamic technologies that we expect manufacturers to use to
comply with the proposed standards, including side skirts and boat
tails, are designed to continue to provide their full potential benefit
indefinitely as long as no serious damage occurs. See also Section
IV.C.6 above describing why we are not proposing separate in-use
standards.
    Regarding trailer tires, we recognize that the original lower
rolling resistance tires will wear over time and will be replaced
several times during the useful life of a trailer, either with new or
retreaded tires. As with the Phase 1 tractor program, to help ensure
that trailer owners have sufficient knowledge of which replacement
tires to purchase in order to retain the as-certified emission and fuel
consumption

performance of their trailer for its useful life, we are proposing to
require that trailer manufacturers supply adequate information in the
owner's manual to allow the trailer owner to purchase replacement tires
meeting or exceeding the rolling resistance performance of the original
equipment tires. We believe that the favorable fuel consumption benefit
of continued use of LRR tires would generally result in proper
replacements throughout the 10-year useful life. Finally, we are
requiring that ATI systems remain effective for at least the 10 year
useful life, although some servicing may be necessary. See the
maintenance discussion in Section IV.D.4.e.
(b) Emission Control Labels
    Historically, EPA-certified vehicles are required to have a
permanent emission control label affixed to the vehicle. The label
facilitates the identification of the vehicle as a certified vehicle.
For the trailer program, EPA proposes that the labels include the same
basic information as we are proposing to require for tractor labels.
For trailers, this information would include the manufacturer, a
trailer identifier such as the Vehicle Identification Number, the
trailer family and regulatory subcategory, the date of manufacture, and
compliance statements. Although the proposed Phase 2 label for tractors
would not include emission control system identifiers (as previously
required for tractors in the Phase 1 program in 40 CFR 1037.135(c)(6)),
we are proposing that these identifiers be included in the trailer
labels. As for tractors, we would require manufacturers to maintain
records that would allow us to verify that an individual trailer was in
its certified configuration.
(c) Warranty
    Section 207 of the CAA requires manufacturers to warrant their
products to be free from defects that would otherwise cause non-
compliance with emission standards. For purposes of the proposed
trailer program, EPA would require trailer manufacturers to warrant all
components that form the basis of the certification to the
CO2 emission standards. The emission-related warranty would
cover all aerodynamic devices, lower rolling resistance tires,
automatic tire inflation systems, and other components that may be
included in the certification application.
    The trailer manufacturer would need to warrant that these
components and systems are designed to remain functional for the
warranty period. Based on the historical practice of requiring
emissions warranties to apply for half of the useful life, we propose
that the warranty period for trailers be 5 years for everything except
tires. For trailer tires, we propose to apply a warranty period of 1
year. Manufacturers could offer a more generous warranty if they chose;
however the emissions related warranty may not be shorter than any
other warranty offered without charge for the vehicle. If aftermarket
components were installed (unrelated to emissions performance) that
offer a longer warranty, this would not impact emission related
warranty obligations of the vehicle manufacturer. NHTSA is not
proposing any warranty requirements relating to its trailer fuel
consumption program.
    At the time of certification, manufacturers would need to supply a
copy of the warranty statement that they would supply to the end
customer. This document would outline what is covered under the GHG
emissions related warranty as well as the duration of coverage.
Customers would also have clear access to the terms of the warranty,
the repair network, and the process for obtaining warranty service.
(d) Maintenance
    In general, EPA requires that vehicle manufacturers specify
maintenance schedules to keep their product in compliance with emission
standards throughout the useful life of the vehicle (CAA section 207).
For trailers, such maintenance could include fairing adjustments or
service to ATI systems. However, EPA believes that any such maintenance
is likely to be performed by operators to maintain the fuel savings of
the components, and we are not proposing that trailer manufacturers be
required submit a maintenance schedule for these components as part of
its application for certification.
    Since low rolling resistance tires are key emission control
components under this program, and will likely require replacement at
multiple points within the life of a vehicle, it is important to
clarify how tires would fit into the emission-related maintenance
requirements. Although the agencies encourage the exclusive use of LRR
tires throughout the life of trailers vehicles, we do not propose to
hold trailer manufacturers responsible for the actions of operators. We
do not see this as problematic because we believe that trailer
operators have a genuine financial motivation for ensuring their
vehicles are as fuel efficient as possible, which includes purchasing
LRR replacement tires. Therefore, as mentioned in Section IV.F.5.a
above, to help ensure that trailer owners have sufficient knowledge of
which replacement tires to purchase in order to retain the as-certified
emission and fuel consumption performance of their trailer, we are
proposing to require that trailer manufacturers supply adequate
information in the owner's manual to allow the trailer owner to
purchase tires meeting or exceeding the rolling resistance performance
of the original equipment tires. We would require that these
instructions be submitted to EPA as part of the application for
certification.
(e) Post-Useful Life Modifications
    Under 40 CFR part 1037, EPA generally prohibits for any person from
removing or rendering inoperative any emission control device installed
to comply with the requirements of 40 CFR part 1037. However, in 40 CFR
1037.655 EPA clarifies that certain vehicle modifications are allowed
after a vehicle reaches the end of its regulatory useful life. EPA is
proposing for this section to apply trailers, since it applies to all
vehicles subject to 40 CFR part 1037, and requests comment on it.
    Generally, this section clarifies that owners may modify a vehicle
for the purpose of reducing emissions, provided they have a reasonable
technical basis for knowing that such modification will not increase
emissions of any other pollutant. In the case of trailers, this
essentially requires a trailer owner to have information that would
lead an engineer or other person familiar with trailer design and
function to reasonably believe that the modifications will not increase
emissions of any regulated pollutant. Thus, this provision does not
provide a blanket allowance for modifications after the useful life.
    This section does not apply with respect to modifications that
occur within the useful life period, other than to note that many such
modifications to the vehicle during the useful life are presumed to
violate 42 U.S.C. 7522(a)(3)(A). EPA notes, however, that this is
merely a presumption, and would not prohibit modifications during the
useful life where the owner clearly has a reasonable technical basis
for knowing the modifications would not cause the vehicle to exceed any
applicable standard.
(6) Flexibilities
    The trailer program that the agencies are proposing incorporates a
number of provisions that would have the effect of providing
flexibility and easing the compliance burden on trailer manufacturers
while maintaining the

expected CO2 and fuel consumption benefits of the program.
Among these is the basic approach we used in setting the proposed
standards, including the staged phase-in of the standards, which would
gradually increase the CO2 and fuel consumption reductions
that manufacturers would need to achieve over time as they also
increase their experience with the program. As described in the general
certification discussion above (Section IV.F.2), another proposed
provision would allow trailer manufacturers to designate broad trailer
families that would aggregate several models with similar technologies
or performance, thus potentially limiting the number of families and
the associated family-level compliance requirements.
    In addition to these provisions inherent to the proposed trailer
program, the agencies are proposing additional options for
certification that we believe would be very valuable to many trailer
manufacturers. One of these is the proposed process for component
manufacturers to submit test data directly to EPA for review by the
agencies in advance of formal certification, allowing a trailer
manufacturer to reduce the amount of testing needed to demonstrate
compliance or avoid it altogether. See Section IV.F.4 above.
(a) Proposed Averaging Provisions
    The agencies are also proposing a limited averaging program as a
part of the trailer compliance process for box trailers. This program
would be similar to the Phase 1 averaging program for other sectors,
but would be narrower in scope to reflect the unique competitive
aspects of the trailer market. The trailer manufacturing industry is
very competitive, and manufacturers must be highly responsive to their
customers' diverse demands. Compared to other industry sectors, this
reality can limit the value of the flexibility that averaging could
provide to trailer manufacturers, since they can have little control
over what kinds of trailer models their customers demand and thus
limited ability to manage the mix and volume of different products. In
addition, the majority of trailer manufacturers have very few basic
trailer models to offer, potentially putting them at a competitive
disadvantage to the small number of larger companies that would be in a
position to meet market demands that the smaller companies could not.
For example, one of the larger, more diverse manufacturers could
potentially supply a customer with trailers that had few if any
aerodynamic features, while offsetting this part of their business with
over-complying trailers that they were able to sell to another
customer; many smaller companies with limited product offerings might
not be able to compete for those customers.
    Although we recognize that there might be potential negative
impacts on at least some trailer manufacturers of an averaging program,
we believe that there may be overall value to such a program. We
propose that full-aero box trailer manufacturers may optionally comply
with their standards on average for a trailer family in any given model
year. We are not proposing to allow partial-aero box trailers to
average. Instead, all trailers in partial-aero families would need to
meet the standard for that subcategory. We are proposing to allow a
trailer manufacturer to combine partial-aero box trailers with the
corresponding full-aero trailer family and reduce the number of
certification applications required. We expect this to be particularly
beneficial to manufacturers in the early years of the program, when
these two trailer categories have identical standards. Although this
option should reduce the compliance paperwork, the partial-aero
trailers would not be able to adopt enough technologies to meet the
full-aero standards in the later years, and manufacturers would have
the option of creating a separate family for these trailers.
Additionally, we are proposing to allow refrigerated trailers to
combine with the dry vans of the same length and meet the dry van
standards and to allow short box vans to combine with their long box
counterparts to meet the long box standards.
    Unlike averaging programs in other sectors, including those in this
Phase 2 program, we propose that averaging be limited to a single model
year, and manufacturer not be allowed to ``bank'' credits generated
from over-compliance in one year for use in a future year. In other
words, a manufacturer that produces some trailers in a family that
perform better than required by the applicable standard would be
allowed to produce a number of trailers that do not meet the standards,
provided the average of the trailers it produces in any given model
year is at or below the standards. A trailer family performing better
than the standard would not be allowed to bank credits for a future
model year.\251\ However, as a temporary recourse for unexpected
challenges in a given model year, we propose that manufacturers be
allowed to generate a deficit that would be resolved within the next
three model years, and to allow the manufacturer to use credits they
generate from over-compliance in subsequent years to address deficits
from prior model years. As discussed below, we are not proposing this
allowance for non-box trailers or non-aero trailers.
---------------------------------------------------------------------------

    \251\ Section IV.F.2 describes the process of identifying
trailer families and sub-families based on basic trailer
characteristics. Section 1037.710 of the proposed regulations
describes the provisions for establishing subfamilies within a
trailer family and the Family Emission Limits that would be averaged
among the subfamilies.
---------------------------------------------------------------------------

    We recognize that at each stage of the program, there may be a
small fraction of trailer applications for which the trailer
manufacturers cannot easily apply all of the aerodynamic and tire
technologies. Thus the proposed dry and refrigerated van standards are
designed in the form of family average performance, meaning that each
trailer manufacturer would comply on average across the trailer
families it produces within each subcategory category (or family). The
proposed program would allow a manufacturer, for example, to comply
without full adoption of aerodynamic devices across 100 percent of its
box trailer production in a trailer family, as long as it also produced
a sufficient number of trailers within that family that performed
better than the standard, such that the overall production-weighted
CO2 and fuel consumption results of the trailer models in
that family complied with the appropriate standard.
    In addition to the flexibility created by averaging, the proposed
box trailer standards themselves are not predicated on a set adoption
rate of any one technology. Manufacturers would be free under the
proposed averaging program to choose to apply the appropriate number
and type of technologies that met their customers' needs and the level
of performance required within a particular trailer family. The
proposed rules in general do not mandate inclusion of any particular
technology or other means of emission control. The agencies believe
that, ordinarily, averaging would create an incentive for manufacturers
to promote high-performing technologies for some customers, beyond the
requirements for that given year, in order to provide other customers
with trailers with fewer aerodynamic technologies.
    The agencies also recognize, however, that an averaging program
would inherently require a higher degree of data management, record
keeping, and reporting than one without averaging. Recognizing that
this could impose burdens, especially on small business manufacturers,
the agencies are proposing that the averaging provisions be optional; a
box trailer manufacturer could choose whether to use averaging

for any or all of its standard box trailer subcategories (families), or
to forego averaging and simply meet the standards with 100 percent of
the production within each family. Also, unlike some other regulated
motor vehicle sectors, we are not proposing that credits from over-
compliance be able to be ``banked'' for use in a later model year, or
to be ``traded'' among trailer manufacturers, since they would
exacerbate the competitive issues, especially for small manufacturers,
as discussed immediately below. However, we are proposing to apply to
trailers the provisions of Phase 1 for tractors that allow for the
generation of a compliance deficit that could be resolved over several
years. Thus, a manufacturer that chose to use averaging, but by the end
of the production year found that a trailer family's CO2 and
fuel consumption values did not reach that year's standards, could
carry a ``deficit'' that would need to be resolved by the third year
following.
    The availability of averaging options also has the potential to be
a disadvantage to some companies in a competitive market that is highly
customer-driven. During the SBREFA process, several manufacturers
expressed concern about their ability to manage their credit balances
in a highly competitive market. Many believe that they would have
little ability to essentially force their customers to purchase the
technology, especially if other manufacturers that had credits were
able to sell trailers without the technology. We see this as especially
problematic for non-box trailers, which are much more likely to be
produced by small businesses, and for which customers may have less
interest in fuel savings technologies since they are less often used
long-haul applications than are box trailers. For these reasons, we are
proposing averaging only for dry and refrigerated vans.
    The agencies understand that averaging is unfamiliar to many
trailer manufacturers and other stakeholders. We have drafted a
supplementary document that includes example scenarios to illustrate
the concept of averaging for a hypothetical box trailer
manufacturer.\252\ Example adoption rates are provided for a standard
compliance strategy (no averaging) and a strategy using the proposed
averaging provisions.
---------------------------------------------------------------------------

    \252\ Memorandum dated March 2015 on Example Compliance
Scenarios for the Proposed GHG Phase 2 Trailer Program. Docket EPA-
HQ-OAR-2014-0827.
---------------------------------------------------------------------------

    One value of averaging that the agencies have historically cited in
several other motor vehicle regulatory programs is that the
availability of averaging provisions made it possible for the agencies
to propose and enact more stringent standards than would otherwise have
been appropriate, recognizing that the expected flexibility of
averaging provisions would ease the path to compliance by the more
challenged members of the industry. In the case of trailer
manufacturers, however, our decisions on the proposed stringency of the
standards is essentially independent of the presence or absence of
averaging, since, as discussed above, averaging provisions may have
relatively less value to manufacturers in this customer-driven industry
and we did not speculate about much or how little it might be used.
    We also request comment on whether the burden of managing an
averaging program could be more trouble than the flexibility is worth.
In the event that averaging were not allowed, the agencies would need
to require that all trailers meeting specified characteristics meet a
minimum stringency level without averaging. If we were to finalize such
non-averaging standards, manufacturers would still be allowed to select
the appropriate technology package that best achieved their emission
performance level, but they would not have the ability to accommodate
customers that may request trailers that perform less well on an
individual trailer basis.
    It is also worth noting that the agencies are not proposing to
allow any generation of early credits before MY 2018. It is clear to us
that small businesses would be less prepared to begin complying early
than larger businesses, and that allowing large manufacturers to
generate early credits that could be used later could put small
businesses at a competitive disadvantage. It does not appear to us that
there would be a sufficient broader programmatic benefit from early
credits to justify such an adverse impact on small businesses.
    We request comment on this proposed averaging option, including
whether the program should allow credit and deficit banking and credit
trading, as well as on any other potential provisions that could
provide compliance flexibility for trailer manufacturers while
achieving the goals of the overall program. Comments supporting
averaging, banking, or trading should explain how these provisions
would be valuable for trailer manufactures across the industry,
including how the provisions would maintain a ``level playing field.''
(b) Proposed SmartWay-Based Certification
    Since many manufacturers have some experience with the SmartWay
program, the agencies are proposing a gradual transition to the
proposed approach that recognizes the parallel SmartWay Technology
Program. The agencies expect aerodynamic device manufacturers to
continue to submit test data to SmartWay for verification. Device
manufacturers that also wish to have their technology available for
trailer manufacturers to use in the Phase 2 program could, in parallel,
submit their test data to EPA for pre-approval for Phase 2 (see Section
IV.F.4). The information obtained by EPA from the device manufacturers
would include the technology name, a description of its proper
installation procedure, and its corresponding delta CDA
derived from the approved test procedures. Any manufacturers that
attained SmartWay verification prior to January 1, 2018 would be
eligible to submit their previous data to EPA's Compliance Division for
pre-approval, provided their test results come from SmartWay's 2014
test protocols that measure a delta CDA. The protocols for
coastdown, wind tunnel, and computational fluid dynamics analyses
result in a CDA value. Note that SmartWay's 2014 protocols
allow SAE J1321 Type 2 track testing, which generates fuel consumption
results, not CDA values. The agencies request comment on
whether we should pre-approve devices tested using SAE J1321 and also
seek comment on an appropriate means of converting from the fuel
consumption results of that test to the delta CDA values
required for trailer compliance.
    Beginning on January 1, 2018, EPA would require that device
manufacturers that wish to seek approval of new technologies for
trailer certification use one of the approved test methods for Phase 2
(i.e., coastdown, constant speed, wind tunnel or CFD) and the test
procedures found in 40 CFR 1037.525. Technologies that were pre-
approved using SmartWay's 2014 Protocols would maintain their approved
status until CY 2021. After January 1, 2021, we are proposing that all
pre-approved aerodynamic trailer technologies be tested using the Phase
2 test procedures.
(c) Off-Cycle Technologies
    The Phase 1 and proposed Phase 2 programs for tractors include
provisions for manufacturers to request the use of off cycle
technologies that are not recognized in GEM or were not in common use
before MY 2010. In the

case of trailers, the agencies are not aware of any technologies that
could improve CO2 and fuel consumption performance that
would not be captured in the test protocols as proposed. We are
therefore not proposing a process to evaluate off-cycle trailer
technologies.
(d) Small Business Regulatory Flexibility Provisions
    As a part of our small business obligations under the Regulatory
Flexibility Act, EPA and NHTSA have considered additional flexibility
provisions aimed at this segment of the trailer manufacturing industry.
EPA convened a Small Business Advocacy Review (SBAR) Panel as required
by the Small Business Regulatory Enforcement Fairness Act (SBREFA), and
much of the information gained and recommendations provided by this
process form the basis of the flexibilities proposed.\253\ As in
previous rulemakings, our justification for including provisions
specific to small businesses is that these entities generally have a
greater degree of difficulty in complying with the standards compared
to other entities. Thus, as discussed below, we are proposing several
regulatory flexibility provisions for small trailer manufacturers that
we believe would reduce the burden on them while achieving the goals of
the program.
---------------------------------------------------------------------------

    \253\ Additional information regarding the findings and
recommendations of the Panel are available in Section XIV, Chapter
11 of the draft RIA, and in the Panel's final report titled ``Final
Report of the Small Business Advocacy Review Panel on EPA's Planned
Proposed Rule Greenhouse Gas Emissions and Fuel Efficiency Standards
for Medium- and Heavy-Duty Engines and Vehicles: Phase 2'' (See
Docket EPA-HQ-OAR-2014-0827).
---------------------------------------------------------------------------

    We believe that the small business regulatory flexibilities
discussed below and in Section XV.C could provide these entities with
reduced compliance requirements and/or additional time to accumulate
capital internally or to secure capital financing from lenders, and to
acquire additional engineering and testing resources.
    The agencies designed many of the proposed program elements and
flexibility provisions available to all trailer manufacturers with the
large fraction of small business trailer manufacturers in mind. We
believe the option to choose pre-approved aerodynamic devices would
significantly reduce the compliance burden and eliminate the
requirement for all manufacturers to perform testing.
    As noted above, the small trailer manufacturers raised concerns
that their businesses could be harmed by provisions allowing averaging,
banking, and trading of emissions and fuel consumption performance,
since they would not be able to generate the same volume of credits as
large manufacturers. The agencies are proposing not to include banking
and trading provisions in any part of the program, and are limiting the
option to average to manufacturers of dry and refrigerated box
trailers. Since a majority of non-box trailer manufacturers are small
businesses, we believe a requirement of specific tire technologies for
all non-box trailers would create the most uniformity in requirements
among manufacturers and would reduce the compliance burden by
eliminating the use of the compliance equation.
    In addition to the provisions offered to trailer manufacturers of
all sizes, the agencies are proposing or requesting comment on several
additional provisions designed specifically to ease compliance burdens
on small trailer manufacturers. For all small business trailer
manufacturers, the agencies propose a one-year delay in the beginning
of implementation of the program, until MY 2019. We believe (subject to
consideration of public comment) that this would allow small businesses
additional needed lead-time to make the proper staffing adjustments and
process changes, and possibly add new infrastructure to meet the
requirements. We also request comment about where there may be
circumstances in later stages of the program, when the stringency of
the standards increase in MY 2021 and 2024, when a similar 1-year delay
in implementation could be warranted for small trailer manufacturers.
    As mentioned previously, we are proposing to offer averaging
provisions for manufacturers of dry and refrigerated box trailers only.
We recognize that the small box trailer manufacturers may not be able
to fully take advantage of averaging and may be at a competitive
disadvantage with larger manufacturers with larger sales volumes and
more diverse product lines. We request comment on additional provisions
that could ease the potential harm to and/or incentivize small business
participation in an averaging program.
    The agencies also request comment on provisions for small
manufacturers that might face a situation where the technologies needed
for compliance are unavailable. This could be a particular concern for
small business non-box and non-aero box trailers that require the use
of LRR tires and ATI systems. We request that trailer manufacturers as
well as tire and aerodynamic technology manufacturers provide
information regarding the current projected availability of the
technologies that trailer manufacturers can use to meet our proposed
standards.

V. Class 2b-8 Vocational Vehicles

A. Summary of Phase 1 Vocational Vehicle Standards

    Class 2b-8 vocational vehicles include a wide variety of vehicle
types, and serve a wide range of functions. Some examples include
service for urban delivery, refuse hauling, utility service, dump,
concrete mixing, transit service, shuttle service, school bus,
emergency, motor homes, and tow trucks. In the HD Phase 1 Program, the
agencies defined Class 2b-8 vocational vehicles as all heavy-duty
vehicles that are not included in the Heavy-duty Pickup Truck and Van
or the Class 7 and 8 Tractor categories. In effect, the rules classify
heavy-duty vehicles that are not a combination tractor or a pickup
truck or van as vocational vehicles. Class 2b-8 vocational vehicles and
their engines emit approximately 20 percent of the GHG emissions and
burn approximately 21 percent of the fuel consumed by today's heavy-
duty truck sector.\254\
---------------------------------------------------------------------------

    \254\ See Memorandum to the Docket ``Runspecs and Model Inputs
for MOVES for HD GHG Phase 2 Emissions Modeling'' Docket Number EPA-
HQ-OAR-2014-0827. See also EPA's MOVES Web page at http://www.epa.gov/otaq/models/moves/index.htm.
---------------------------------------------------------------------------

    Most vocational vehicles are produced in a two-stage build process,
though some are built from the ``ground up'' by a single entity. In the
two-stage process, the first stage sometimes is completed by a chassis
manufacturer that also builds its own proprietary components such as
engines or transmissions. This is known as a vertically integrated
manufacturer. The first stage can also be completed by a chassis
manufacturer who procures all components, including the engine and
transmission, from separate suppliers. The product completed at the
first stage is generally either a stripped chassis, a cowled chassis,
or a cab chassis. A stripped chassis may include a steering column, a
cowled chassis may include a hood and dashboard, and a cab chassis may
include an enclosed driver compartment. Many of the same companies that
build Class 7 and 8 tractors also sell vocational chassis in the medium
heavy- and heavy heavy-duty weight classes. Similarly, some of the
companies that build Class 2b and 3 pickups and vans also sell
vocational chassis in the light heavy-duty weight classes.

    The second stage is typically completed by a final stage
manufacturer or body builder, which installs the primary load carrying
device or other work-related equipment, such as a dump bed, delivery
box, or utility boom. There are over 200 final stage manufacturers in
the U.S., most of which are small businesses. Even the large final
stage manufacturers are specialized, producing a narrow range of
vehicle body types. These businesses also tend to be small volume
producers. In 2011, the top four producers of truck bodies sold a total
of 64,000 units, which is about 31 percent of sales in that year.\255\
In that same year, 74 percent of final stage manufacturers produced
less than 500 units.
---------------------------------------------------------------------------

    \255\ Specialty Transportation.net, 2012. Truck Body
Manufacturing in North America.
---------------------------------------------------------------------------

    The businesses that act both as the chassis manufacturer and the
final stage manufacturer are those that build the vehicles from the
``ground up.'' These entities generally produce custom products that
are sold in lower volumes than those produced in large commercial
processes. Examples of vehicles produced with this build process would
include fire apparatus and transit buses.
    The diversity in the vocational vehicle segment can be primarily
attributed to the variety of customer needs for specialized vehicle
bodies and added equipment, rather than to the chassis. For example, a
body builder can build either a Class 6 bucket truck or a Class 6
delivery truck from the same Class 6 chassis. The aerodynamic
difference between these two vehicles due to their bodies would lead to
different in-use fuel consumption and GHG emissions. However, the
baseline fuel consumption and emissions due to the components included
in the common chassis (such as the engine, drivetrain, frame, and
tires) would be the same between these two types of vehicles.
    Owners of vocational vehicles that are upfitted with high-priced
bodies that are purpose-built for particular applications tend to keep
them longer, on average, than owners of vehicles such as pickups, vans,
and tractors, which are traded in broad markets that include many
potential secondary markets. The fact that vocational vehicles also
generally accumulate far fewer annual miles than tractors further
contributes to lengthy trade cycles among owners of these vehicles. To
the extent vocational vehicle owners may be similar to owners of
tractors in terms of business profiles, they would be more likely to
resemble private fleets or owner-operators than for-hire fleets. A 2013
survey conducted by NACFE found that the trade cycle of private tractor
fleets ranged from seven to 12 years.\256\
---------------------------------------------------------------------------

    \256\ See 2013 ICCT Barriers Report at Note 241, above.
---------------------------------------------------------------------------

    The Phase 1 standards for this vocational vehicle category
generally apply at the chassis manufacturer level. For the same reasons
given in Phase 1, the agencies propose to apply the Phase 2 vocational
vehicle standards at the chassis manufacturer level.\257\
---------------------------------------------------------------------------

    \257\ See 76 FR 57120.
---------------------------------------------------------------------------

    The Phase 1 regulations prohibit the introduction into commerce of
any heavy-duty vehicle without a valid certificate or exemption. 40 CFR
1037.620, redesignated as 40 CFR 1037.622 in the proposed rule, allows
for a temporary exemption for the chassis manufacturer if it produces
the chassis for a secondary manufacturer that holds a certificate.
Further discussion of temporary exemptions and possible obligations of
secondary manufacturers can be found in Section V. E.
    In Phase 1, the agencies adopted two equivalent sets of standards
for Class 2b-8 vocational vehicles. For vehicle-level (chassis)
emissions, EPA adopted CO2 standards expressed in grams per
ton-mile. For fuel efficiency, NHTSA adopted fuel consumption standards
expressed in gallons per 1,000 ton-miles. The Phase 1 engine-based
standards vary based on the expected weight class and usage of the
vehicle into which the engine will be installed. We adopted Phase 1
vehicle-based standards that vary according to one key attribute, GVWR,
based on the same groupings of vehicle weight classes used for the
engine standards--light heavy-duty (LHD, Class 2b-5), medium heavy-duty
(MHD, Class 6-7), and heavy heavy-duty (HHD, Class 8).
    In Phase 1, the agencies defined a special regulatory category
called vocational tractor, which generally operate more like vocational
vehicles than line haul tractors.\258\ As described above in Section
III.C.4, under the Phase 1 rules, a vocational tractor is certified
under standards for vocational vehicles, not those for tractors. In
Phase 2, the agencies propose to retain the vocational tractor
definition, and to allow vocational tractors to certify over any of the
proposed vocational vehicle duty cycles, following the same decision-
tree as other vocational chassis. Vocational tractors would continue to
satisfy the proposed engine standard and vocational vehicle GEM-based
standard, rather than the proposed tractor standard.
---------------------------------------------------------------------------

    \258\ See EPA's regulation at 40 CFR 1037.630 and NHTSA's
regulation at 49 CFR 523.2.
---------------------------------------------------------------------------

    Manufacturers are required to use GEM to determine compliance with
the Phase 1 vocational vehicle standards, where the primary vocational
vehicle manufacturer-generated input is the measure of tire rolling
resistance. The GEM assumes the use of a typical representative,
compliant engine in the simulation, resulting in one overall value for
CO2 emissions and one for fuel consumption. The
manufacturers of engines intended for use in vocational vehicles are
subject to separate Phase 1 engine-based standards. Manufacturers also
may demonstrate compliance with the CO2 standards in whole
or in part using credits reflecting CO2 reductions resulting
from technologies not reflected in the GEM testing regime. See 40 CFR
1037.610.
    In Phase 1, EPA and NHTSA also adopted provisions designed to give
manufacturers a degree of flexibility in complying with the standards.
Most significantly, we adopted an ABT program to allow manufacturers
within the same averaging set to comply on average. See 40 CFR part
1037, subpart H. These provisions enabled the agencies to adopt overall
standards that are more stringent than we could have considered with a
less flexible program.\259\
---------------------------------------------------------------------------

    \259\ As noted earlier, NHTSA notes that it has greater
flexibility in the HD program to include consideration of credits
and other flexibilities in determining appropriate and feasible
levels of stringency than it does in the light-duty CAFE program.
Cf. 49 U.S.C. 32902(h), which applies to light-duty CAFE but not to
heavy-duty fuel efficiency under 49 U.S.C. 32902(k).
---------------------------------------------------------------------------

B. Proposed Phase 2 Standards for Vocational Vehicles

    The agencies have held dozens of meetings with manufacturers,
suppliers, non-governmental organizations (NGOs), and other
stakeholders to identify and understand the opportunities and
challenges involved with regulating vocational vehicles. These meetings
have helped us to better understand the performance demands of the
customers, the fuel-saving and GHG reducing technologies that are being
investigated, as well as some challenges that are being encountered. In
addition, we updated our industry characterization to better understand
the vocational vehicle manufacturing process, including the component
suppliers and body builders.\260\ We believe these information
exchanges have enabled us to develop this proposal with an appropriate
balance of

reasonably achievable goals and a reasonably small risk of unintended
consequences.
---------------------------------------------------------------------------

    \260\ September 2013, Heavy Duty Vocational Vehicle Industry
Characterization, EPA Contract No. EP-C-12-011.
---------------------------------------------------------------------------

(1) Proposed Subcategories and Test Cycles

    The proposed Phase 2 vocational vehicle standards are based on the
performance of a wider array of control technologies than the Phase 1
rules. In particular, the agencies are proposing to recognize detailed
characteristics of powertrains and drivelines in the proposed Phase 2
vocational vehicle standards. As described below, driveline
improvements present a significant opportunity for reducing fuel
consumption and CO2 emissions from vocational vehicles.
However, there is no single package of driveline technologies that
would be equally suitable for the majority of vocational vehicles,
because there is an extremely broad range of driveline configurations
available in the market. This is due in part to the variety of build
processes, ranging from a purpose built custom chassis to a commercial
chassis that may be intended as a multi-purpose stock vehicle. Further,
the wide range of applications and driving patterns of these vehicles
leads manufacturers to offer a variety of drivelines, as each performs
differently in use. For example, depending on whether the transmission
has an overdrive gear, drive axle ratios for Class 7 and 8 tractors can
be found in the range of 2.5:1 to 4.1:1. By contrast, across all types
of vocational vehicles, drive axle ratios can be as low as 3.1:1
(delivery vehicle) and as high as 9.8:1 (transit bus).\261\ Other
components of the driveline also have a broader range of product in
vocational vehicles than in tractors, including transmission gears,
tire sizes, and engine speeds. Each of these design features affects
the GHG emission rate and fuel consumption of the vehicle. It therefore
is reasonable to define more than one baseline configuration of
vocational vehicle, to encompass a range of drivelines and recognize
that the agencies cannot use a one-size-fits-all approach. A detailed
list of the technologies the agencies project could be adopted to meet
the proposed vocational vehicle standards is described in Section V.C,
and in the draft RIA Chapter 2. The agencies have determined that these
technologies perform differently depending on the drivelines and
driving patterns, further supporting the need to subcategorize this
segment.
---------------------------------------------------------------------------

    \261\ See Dana Spicer Drive Axle Application Guidelines,
available at http://www.dana.com/wps/wcm/connect/133007004bd8422b9ea8be14e7b6dae0/DEXT-daag2012_0712_DriveAxlesAppGuide_LR.pdf?MOD=AJPERES&CONVERT_TO=url&CACHEID=133007004bd8422b9ea8be14e7b6dae0. See also ZF Driveline and
Chassis Technology brochure, available at http://www.zf.com/media/media/en/document/corporate_2/downloads_1/flyer_and_brochures/bus_driveline_technology_flyer/Busbroschuere_12_DE_final.pdf
---------------------------------------------------------------------------

    For these reasons, the agencies are proposing to create additional
subcategories of vocational vehicles in Phase 2. By creating additional
subcategories we would essentially be setting separate baselines and
separate numerical performance standards for different groups of
vocational vehicle chassis over different test cycles. This would
enable the technologies that perform best at highway speeds and those
that perform best in urban driving to each to be fully recognized over
appropriate test cycles, while avoiding the unintended consequence of
forcing vocational vehicles that are designed to serve in a wide
variety of applications to be measured against a single baseline. The
attributes we believe could define these chassis groups are described
below.
    The agencies are proposing to split groups of chassis into
subcategories based generally on vehicle use patterns in which the
CO2 emissions and fuel consumption standards vary as a
consequence. Compliance with these standards would be demonstrated
through test cycles reflecting these use patterns, to best assure that
actual in-use benefits occur. An ideal test cycle is one in which the
performance improvements achieved by the adopted technologies are
recognized over the cycle. As described in Section V.C and in the draft
RIA Chapter 2.9, the agencies have found that most of the technologies
considered do perform differently under different driving conditions.
For example, the effectiveness of lower tire rolling resistance is
different depending on the degree of highway or transient driving, but
the differences are very small compared to the difference in
effectiveness for a hybrid drivetrain under different driving
conditions. The agencies have found that the measurable changes in
performance of a majority of the technologies are significant enough to
merit creation of different subcategories with different test cycles.
    Idle reduction technology is one type of technology that is
particularly duty-cycle dependent. The composite test cycle for
vocational vehicles in Phase 1 includes a 42 percent weighting on the
ARB Transient test cycle, which comprises nearly 17 percent of idle
time. However, no single idle event in this test cycle is longer than
36 seconds, which may not be enough time to adequately recognize the
benefits of some idle reduction technologies.\262\ For Phase 2, the
agencies propose to recognize this important fuel saving technology by
evaluating workday idle reduction technologies through a new idle-only
cycle as described in the draft RIA Chapter 3.
---------------------------------------------------------------------------

    \262\ However, as noted above, emission improvements due to
workday idle technology can be recognized under Phase 1 as an
innovative credit under 40 CFR 1037.610 and 49 CFR 535.7.
---------------------------------------------------------------------------

    The agencies are proposing three different composite test cycles
for vocational vehicles in Phase 2: Regional, Multi-Purpose, and Urban.
The agencies believe these three cycles balance the competing pressures
to recognize the varying performance of technologies, serve the varying
needs of customers, and maintain reasonable regulatory simplicity.
Table V-1 below presents the nine proposed subcategories of vocational
vehicles: Three weight class groupings, each with three composite duty
cycles. Each of these proposed composite duty cycles has a different
weighting of the new idle cycle, the highway cruise cycles, and the ARB
Transient cycle, as shown in Table V-2. The CALSTART HD Truck Fuel
Economy Task Group met in June 2013 to discuss vocational vehicle
segmentation, and suggested an approach very similar to this. The task
group generally supported a limited number of duty cycles that would be
sufficient to cover the basic applications while allowing new
technology to demonstrate its worth. They recognized that a few
meaningful duty cycles could ``bound'' how vocational vehicles are
generally used, while recognizing that this approach would not
perfectly match how every vocational vehicle is actually used. Their
recommendations included three vocational vehicle duty-cycle-based
subcategories: Urban, Regional, and Work Site. A detailed discussion of
the CALSTART recommendations, as well as reasoning why the agencies
selected the proposed composite cycle weightings can be found in the
draft RIA Chapter 2. Continuing the averaging scheme from Phase 1, each
manufacturer would be able to average within each vehicle weight class.

                      Table V-1--Proposed Regulatory Subcategories for Vocational Vehicles
----------------------------------------------------------------------------------------------------------------
                              Light heavy-duty class 2b-  Medium heavy-duty class 6-
        Weight class                       5                           7               Heavy heavy-duty class 8
----------------------------------------------------------------------------------------------------------------
Duty Cycle..................  Regional..................  Regional..................  Regional.
                              Multi-Purpose.............  Multi-Purpose.............  Multi-Purpose.
                              Urban.....................  Urban.....................  Urban.
----------------------------------------------------------------------------------------------------------------

            Table V-2--Proposed Composite Test Cycle Weightings (in Percent) for Vocational Vehicles
----------------------------------------------------------------------------------------------------------------
                                                                   55 mph cruise   65 mph cruise
                                                   ARB transient     with road       with road         Idle
                                                                     grade \a\       grade \a\
----------------------------------------------------------------------------------------------------------------
Regional........................................              50              28              22              10
Multi-Purpose...................................              82              15               3              15
Urban...........................................              94               6               0              20
----------------------------------------------------------------------------------------------------------------
Note:
\a\ As described in Section III.E.2.b, the agencies are proposing to add road grade to the highway cruise test
  cycles.

    The agencies are proposing criteria for determining the
applicability of these subcategories. This is not as straightforward an
exercise as with tractors, where attributes such as cab type are
obvious physical properties that indicate reasonably well how a vehicle
is intended to be used. The agencies have identified the final drive
ratio of a vocational vehicle as a possible attribute that may indicate
how the vehicle is intended to be used. As described in Section
V.E.(1)(d), we expect that most vocational chassis could be assigned to
a duty cycle by estimating the percent of maximum engine test speed
that is achieved over highway cruise cycles, by use of an equation that
relates engine speed to vehicle speed. To simplify this assignment
process, the agencies propose that a vocational chassis would be
presumed to certify using the Multi-Purpose duty cycle unless some
criteria were met that indicated either the Regional or Urban cycle
would be more appropriate. Those criteria could include the objective
calculation described in Section V.E., or a mix of physical attributes
and knowledge of intended use. The agencies are also proposing that
chassis manufacturers would be able to request a different duty cycle.
    We understand that even within certain vocational vehicle types,
vehicle use varies significantly. By employing the agencies'
recommended assignment process, it is our expectation that a delivery
truck and a dump truck could both be certified over the same duty cycle
while still yielding accurate technology effectiveness, if they had
similar chassis and driveline characteristics. Further, while intended
service class may help a manufacturer decide how to classify some
vehicles, we do not believe that intended service class would be a
sufficient indicator by itself. An example of this is the refuse
service class. A neighborhood collection refuse truck would not need to
be assigned to the same subcategory as a roll-off refuse straight/dump
truck that makes daily highway trips to a landfill.
    The agencies request comment on the method for assigning vocational
chassis to regulatory subcategories. We believe the proposed approach
is aligned with the objective to allow manufacturers to certify their
chassis over appropriate duty cycles, while maintaining the ability of
the market to offer a variety of products to meet customer demand.
(2) Alternative Approach to Subcategorization
    The U.S. Department of Energy and EPA are partnering to support a
project aimed at evaluating, refining and/or developing duty cycles for
tractors and vocational vehicles to be used in the certification of
heavy-duty vehicles to GHG emission standards. This project is underway
at the National Renewable Energy Laboratory (NREL) and includes a task
to develop alternative subcategorization options for vocational
vehicles, along with new drive cycles and/or cycle composite
weightings. NREL is continuing to collate available vehicle activity
data and vehicle characteristics, and the public is invited to submit
information to the docket in support of this work to identify possible
alternative GEM test cycles and segmentation options for vocational
vehicles. Preliminary work under this project indicates that two or
three test cycles may adequately represent most vocational vehicles.
Depending on how many distinct vehicle driving patterns can be
identified with correlation to vehicle attributes, the agencies may
finalize a vocational subcategorization approach that includes as few
as two or as many as five composite GEM duty cycles. It is also
possible that some test cycles may not apply to all subcategories. It
is further possible that the approach to assignment of vocational
chassis to subcategories in the final rules may be based on different
attributes than those proposed, including different engine and
driveline characteristics and different indicators of vehicle purpose.
Preliminary work from NREL indicates that in-use drive cycles may
include more idle operation for all types of vocational vehicles than
is represented by the currently proposed GEM test cycles. Depending on
comments and additional information received during the comment period,
it may be within the agencies' discretion to adopt one or more
alternative vocational vehicle test cycles, or re-weight the current
test cycles, to better represent real world driving and better reflect
performance of the technology packages.
(3) Proposed GHG and Fuel Consumption Standards for Vocational Vehicles
    EPA is proposing CO2 standards and NHTSA is proposing
fuel consumption standards for manufacturers of chassis for new
vocational vehicles. As described in Sections II.C.1 and II.D.1 above,
the agencies are proposing test procedures so that engine performance
would be evaluated within the GEM simulation tool. These test
procedures include corrections for the test fuel, enabling vocational
vehicles to be certified with many different types of CI and SI
engines. In addition, EPA is proposing to establish HFC leakage
standards for air conditioning systems in vocational vehicles, as
described

below and in the draft RIA Chapters 2 and 5.
    This section describes the standards and implementation dates that
the agencies are proposing for the nine subcategories of vocational
vehicles. The agencies have performed a technology analysis to
determine the level of standards that we believe would be available at
reasonable cost, and would be cost-effective, technologically feasible,
and appropriate in the lead time provided. More details of this
analysis are described in the draft RIA Chapter 2. This analysis
considered the following for each of the proposed regulatory
subcategories:
     The level of technology that is incorporated in current
new vehicles,
     forecasts of manufacturers' product redesign schedules,
     the available data on CO2 emissions and fuel
consumption for these vehicles,
     technologies that would reduce CO2 emissions
and fuel consumption and that are judged to be feasible and appropriate
for these vehicles through the 2027 model year,
     the effectiveness and cost of these technologies,
     a projection of the technologically feasible application
rates of these technologies, in this time frame, and
     projections of future U.S. sales for different types of
vehicles and engines.
    The proposal described here and throughout the rulemaking documents
is the preferred alternative, referred to as Alternative 3 in Section X
and the draft RIA Chapter 11. However, the agencies are seriously
considering another alternative for all segments, including vocational
vehicles, referred to as Alternative 4. The agencies believe that
Alternative 4 has the potential to be the maximum feasible and
reasonable alternative. However, based on the evidence currently before
the agencies, EPA and NHTSA have outstanding questions regarding
relative risks and benefits of Alternative 4 due to the time frame
envisioned by that alternative. Alternative 4 is predicated on the same
general market adoption rates of the same technologies as the proposal,
but would provide three years less lead time than the proposal. Details
of Alternative 4 are presented in Section V.D, Section X, and in the
draft RIA Chapter 11.
    The agencies seek comment on the feasibility of Alternative 4 for
vocational vehicles, including empirical data on its appropriateness,
cost-effectiveness, and technological feasibility. It would be helpful
if comments addressed these issues separately for each type of
technology.
    Additional information and feedback could further inform our
assumptions and, by extension, our analysis of feasibility. The
agencies believe it is possible that it could be within the agencies'
discretion to determine in the final rules that Alternative 4 could be
maximum feasible and appropriate under CAA section 202(a)(1) and (2).
If the agencies receive relevant information supporting the feasibility
of Alternative 4, or regarding technology pathways different than those
in Alternatives 3 and 4, the agencies may consider establishing final
fuel consumption and GHG emission standards at levels 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.
(a) Proposed Fuel Consumption and CO2 Standards
    The agencies are proposing standards that would phase in over a
period of seven years, beginning in the 2021 model year, consistent
with the requirement in EISA that NHTSA's standards provide four full
model years of regulatory lead time and three full model years of
regulatory stability, and provide sufficient time ``to permit the
development and application of the requisite technology'' for purposes
of CAA section 202(a)(2). The proposed Phase 2 program would progress
in three-year stages with an intermediate set of standards in MY 2024
and would continue to reduce fuel consumption and CO2
emissions well beyond the full implementation year of MY 2027. The
agencies have identified a technology path for each of these levels of
improvement, as described below.
    Combining engine and vehicle technologies, vocational vehicles
powered by CI engines would be projected to achieve improvements of 16
percent in MY 2027 over the MY 2017 baseline, as described below and in
the draft RIA Chapter 2. The agencies project up to 13 percent
improvement in fuel consumption and CO2 emissions in MY 2027
from SI-powered vocational vehicles, as shown in Table V-3. The
incremental Phase 2 vocational vehicle standards would ensure steady
progress toward the MY 2027 standards, with improvements in MY 2021 of
up to seven percent and improvements in MY 2024 of up to 11 percent
over the MY 2017 baseline vehicles, as shown in Table V-3.
    The agencies' analyses, as discussed in this preamble and in the
draft RIA Chapter 2, show that the proposed standards would be
appropriate under each agency's respective statutory authority.

       Table V-3--Projected Vocational Vehicle CO2 and Fuel Use Reductions (in Percent) From 2017 Baseline
----------------------------------------------------------------------------------------------------------------
                                                                                Light heavy-
              Model year                       Engine type         Heavy heavy-    Medium heavy-  duty class  2b-
                                                                   duty class 8   duty class 6-7         5
----------------------------------------------------------------------------------------------------------------
2021..................................  CI Engine...............               7               7               6
                                        SI Engine...............               5               5               4
2024..................................  CI Engine...............              11              11              10
                                        SI Engine...............               7               7               7
2027..................................  CI Engine...............              16              16              16
                                        SI Engine...............              12              13              12
----------------------------------------------------------------------------------------------------------------

    Based on our analysis and research, the agencies believe that the
improvements in vocational vehicle fuel consumption and CO2
emissions can be achieved through deployment and utilization of a
greater set of technologies than formed the technology basis for the
Phase 1 standards. In developing the proposed standards, the agencies
have evaluated the current levels of fuel consumption and emissions,
the kinds of technologies that could be utilized by manufacturers to
reduce fuel consumption and emissions, the associated lead time, the
associated costs for the industry, fuel savings for the owner/operator,
and the magnitude of the CO2 reductions and fuel savings
that may be achieved. After examining the possibilities of vehicle
improvements, the agencies are basing the proposed standards on the
performance of workday idle reduction technologies, improved
transmissions

including hybrid powertrains, axle technologies, weight reduction, and
further tire rolling resistance improvements. The EPA-only air
conditioning standard is based on leakage improvements.
    The agencies' evaluation indicates that some of the above vehicle
technologies are commercially available today, though often in limited
volumes. Other technologies would need additional time for development.
Those that we believe are available today and may be adopted to a
limited extent in some vehicles include improved tire rolling
resistance, weight reduction, some types of conventional transmission
improvements, neutral idle, and air conditioning leakage improvements.
However, EPA is not proposing standards predicated on performance of
these technologies until MY 2021.\263\ The agencies consider any
potential benefits that could be achieved by implementing rules
requiring some technologies on vocational vehicles earlier than MY 2021
to be outweighed by several disadvantages. For one, manufacturers would
need lead time to develop compliance tracking tools. Also, if the Phase
2 vocational vehicle standards began in a different year than the
tractor standards, this could create unnecessary added complexity, and
could strongly detract from the fuel savings and GHG emission
reductions that could otherwise be achieved. Therefore we anticipate
that the Phase 1 standards will continue to apply in model years 2018
to 2020.
---------------------------------------------------------------------------

    \263\ NHTSA is unable to adopt mandatory amended standards in
those model years since there would be less than the statutorily-
prescribed amount of lead time available. 49 U.S.C. 32902(k)(3)(A).
---------------------------------------------------------------------------

    Vehicle technologies that we believe will become available in the
near term include improved axle lubrication and 6x2 axles. Vehicle
technologies that we understand would benefit from even more
development time include stop-start idle reduction and hybrid
powertrains. The agencies have analyzed the technological feasibility
of achieving the fuel consumption and CO2 standards, based
on projections of what actions manufacturers would be expected to take
to reduce fuel consumption and emissions to achieve the standards, and
believe that the standards would be technologically feasible throughout
the regulatory useful life of the program. EPA and NHTSA estimated
vehicle package costs are found in Section V.C.(2).
    Table V-4 and Table V-5 present EPA's proposed CO2
standards and NHTSA's proposed fuel consumption standards,
respectively, for chassis manufacturers of Class 2b through Class 8
vocational vehicles for the beginning model year of the program, MY
2021. As in Phase 1, the standards would be in the form of the mass of
emissions, or gallons of fuel, associated with carrying a ton of cargo
over a fixed distance. The EPA standards would be measured in units of
grams CO2 per ton-mile and the NHTSA standards would be in
gallons of fuel per 1,000 ton-miles. With the mass of freight in the
denominator of this term, the program is designed to measure improved
efficiency in terms of freight efficiency. As in Phase 1, the Phase 2
program would assign a fixed default payload in GEM for each vehicle
weight class group (heavy heavy-duty, medium heavy-duty, and light
heavy-duty). Even though this simplification does not allow individual
vehicle freight efficiencies to be recognized, the general capacity for
larger vehicles to carry more payload is represented in the numerical
values of the proposed standards for each weight class group.
    EPA's proposed vocational vehicle CO2 standards and
NHTSA's proposed fuel consumption standards for the MY 2024 stage of
the program are presented in Table V-6 and Table V-7, respectively.
These reflect broader adoption rates of vehicle technologies already
considered in the technology basis for the MY 2021 standards. The
standards for vehicles powered by CI engines also reflect that in MY
2024, the separate engine standard would be more stringent, so the
vehicle standard keeps pace with the engine standard.
    EPA's proposed vocational vehicle CO2 standards and
NHTSA's proposed fuel consumption standards for the full implementation
year of MY 2027 are presented in Table V-8 and Table V-9, respectively.
These reflect even greater adoption rates of the same vehicle
technologies considered in the basis for the previous stages of the
Phase 2 standards. The proposed MY 2027 standards for vocational
vehicles powered by CI engines reflect additional engine technologies
consistent with those on which the separate proposed MY 2027 CI engine
standard is based. The proposed MY 2027 standards for vocational
vehicles powered by SI engines reflect improvements due to additional
engine friction reduction technology, which is not among the
technologies on which the separate SI engine standard is based.
    The proposed standards are based on highway cruise cycles that
include road grade, to better reflect real world driving and to help
recognize engine and driveline technologies. See Section III.E. The
agencies have evaluated some alternate road grade profiles, including
several recommended by NREL and two developed independently by the
agencies, and have prepared possible alternative vocational vehicle
standards based on these profiles. The agencies request comment on this
analysis, which is available in a memorandum to the docket.\264\
---------------------------------------------------------------------------

    \264\ See Memorandum dated May 2015 on Possible Tractor,
Trailer, and Vocational Vehicle Standards Derived from Alternative
Road Grade Profiles.
---------------------------------------------------------------------------

    As described in Section I, the agencies are proposing to continue
the Phase 1 approach to averaging, banking and trading (ABT), allowing
ABT within vehicle weight classes. For Phase 2, continuing this
approach means allowing averaging between CI-powered vehicles and SI-
powered vehicles that belong to the same weight class group and have
the same regulatory useful life.

                Table V-4--Proposed EPA CO2 Standards for MY 2021 Class 2b-8 Vocational Vehicles
----------------------------------------------------------------------------------------------------------------
                                                                   Light heavy-
                           Duty cycle                             duty class 2b-   Medium heavy-   Heavy heavy-
                                                                         5        duty class 6-7   duty class 8
----------------------------------------------------------------------------------------------------------------
                  EPA Standard for Vehicle with CI Engine Effective MY 2021 (gram CO2/ton-mile)
----------------------------------------------------------------------------------------------------------------
Urban...........................................................             296             188             198
Multi-Purpose...................................................             305             190             200
Regional........................................................             318             186             189