vehicle simulation model we used to develop the proposed standards (as
described in Section IV. D. (3) (a) below). Lower numerical values in
Table IV-2 do not necessarily indicate more stringent standards. For
instance, the proposed standards for dry and refrigerated vans of the
same length have the same stringency through MY 2026, but the standards
recognize differences in trailer weight and aerodynamic performance due
to the TRU on refrigerated vans. Trailers of the same type but
different length differ in weight as well as in the number of axles
(and tires), tractor type, payload and aerodynamic performance. Section
IV. D. and Chapter 2.10 of the draft RIA provide more details on the
characteristics of the tractor-trailer vehicles, with various
technologies, that are the basis for these standards.
    In developing the proposed standards for trailers, the agencies
evaluated the current level of CO2 emissions and fuel
consumption, the types and availability of technologies that could be
applied to reduce CO2 and fuel consumption, and the current
adoption rates of these technologies. Additionally, we considered the
necessary lead-time and associated costs to the industry to meet these
standards, as well as the fuel savings to the consumer and magnitude of
CO2 and fuel savings that we project would be achieved as a
result of these proposed standards. As discussed in more detail later
in this preamble and in Chapter 2.10 of the draft RIA, the analyses of
trailer aerodynamic and tire technologies that the agencies have
conducted appear to show that these proposed standards would be the
maximum feasible and appropriate in the lead-time provided under each
agency's respective statutory authorities. We ask that any comments
related to stringency include data whenever possible indicating the
potential effectiveness and cost of adding such devices to these
vehicles.
    The agencies request comment on all aspects of these proposed
standards, including trailers to be covered and the proposed 50-foot
demarcation between ``long'' and ``short'' box vans, the proposed
phase-in schedule, and the stringency of the standards in relation to
their cost, CO2 and fuel consumption reductions, and on the
proposed compliance provisions, as discussed in Section IV. F.
    In addition to these proposed trailer standards, the agencies
considered standards both less stringent and more stringent than the
proposed standards. We specifically request comment on a set of
accelerated standards that we considered, as presented in Section IV.
E. This set of standards is predicated on performance and penetration
rates of the same technologies as the proposed standards, but would
reach full implementation three years sooner.
(3) Lead-Time Considerations
    As mentioned earlier, although the agencies did not include
standards for trailers in Phase 1, box trailer manufacturers have been
gaining experience with CO2- and fuel consumption-reducing
technologies over the past several years, and the agencies expect that
trend to continue, due in part to EPA's SmartWay program and
California's Tractor-Trailer Greenhouse Gas Regulation. Most
manufacturers of long box trailers have some experience installing
these aerodynamic and tire technologies for customers. This experience
impacts how much lead-time is necessary from a technological
perspective. EPA is proposing CO2 emission standards for
long box trailers for MY 2018 that represent stringency levels similar
to those used for SmartWay verification and required for the California
regulation, and thus could be met by adopting off-the-shelf aerodynamic
and tire technologies available today. The NHTSA program from 2018
through 2020 would be voluntary.
    Manufacturers of trailers other than 53-foot box vans do not have
the benefit of programs such as SmartWay to provide a reliable
evaluation and promotion of these technologies for their trailers and
therefore have less experience with these technologies. As such, EPA is
proposing less stringent requirements for manufacturers of other
highway trailer subcategories beginning in MY 2018. We expect these
manufacturers of short box trailers would adopt some aerodynamic and
tire technologies, and manufacturers of other trailers would adopt tire
technologies only, as a means of achieving the proposed standards. Some
manufacturers of trailers other than long boxes may not yet have direct
experience with these technologies, but the technologies they would
need are fairly simple and can be incorporated into trailer production
lines without significant process changes. Also, the NHTSA program for
these trailers would be voluntary until MY 2021.
    The agencies believe that the burdens of installing and marketing
these technologies would not be limiting factors in determining
necessary lead-time for manufacturers of these trailers. Instead, we
expect that the proposed first-time compliance and, in some cases,
performance testing requirements, would be the more challenging
obstacles for this newly regulated industry. For these reasons, we are
proposing that these standards phase in over a period of nine years,
with flexibilities that would minimize the compliance and testing
burdens in the early years of the proposed program (see Section IV.
F.).
    As mentioned previously, EPA is proposing modest standards and
several compliance options that would allow it to begin its program for
MY 2018. However, EISA requires four model years of lead-time for fuel
consumption standards, regardless of the stringency level or
availability of flexibilities. Therefore, NHTSA's proposed fuel
consumption requirements would not become mandatory until MY 2021.
Prior to MY 2021, trailer manufacturers could voluntarily participate
in NHTSA's program, noting that once they made such a choice, they
would need to stay in the program for all succeeding model years.\216\
---------------------------------------------------------------------------

    \216\ NHTSA adopted a similar voluntary approach in the first
years of Phase 1 (see 76 FR 57106).
---------------------------------------------------------------------------

    The agencies believe that the expected period of seven years or
more between the issuing of the final rules and full implementation of
the program would provide sufficient lead-time for all affected trailer
manufacturers to adopt CO2- and fuel consumption-reducing
technologies or design trailers to meet the proposed standards.
(4) Non-CO2 GHG Emissions from Trailers
    In addition to the impact of trailer design on the CO2
emissions of tractor-trailer vehicles, the agencies recognize that
refrigerated trailers can also be a source of emissions of HFCs.
Specifically, HFC refrigerants that are used in transport refrigeration
units (TRUs) have the potential to leak into the atmosphere. We do not
currently believe that HFC leakage is likely to become a major problem
in the near future, and we are not proposing provisions addressing
refrigerant leakage of trailer-related HFCs in this proposed
rulemaking. TRUs differ from the other source categories where EPA has
adopted (or proposed) to apply HFC leakage requirements (i.e., air
conditioning). We believe trailer owners have a strong incentive to
limit refrigerant leakage in order to maintain the operability of the
trailer's refrigeration unit and avoid financial liability for damage
to perishable freight due to a failure to maintain the agreed-

upon temperature and humidity conditions. In addition, refrigerated van
units represent a relatively small fraction of new trailers.
Nevertheless, we request comment on this issue, including any data on
typical TRU charge capacity, the frequency of HFC refrigerant leakage
from these units across the fleet, the magnitude of unaddressed leakage
from individual units, and how potential EPA regulations might address
this leakage issue.
(5) Exclusions and Less-Stringent Standards
    All trailers built before January 1, 2018 are excluded from the
Phase 2 trailer program, and from 40 CFR part 1037 and 49 CFR part 535
in general (see 40 CFR 1037.5(g) and 49 CFR 535.3(e)). Furthermore, the
proposed regulations do not apply to trailers designed to be drawn by
vehicles other than tractors, and those that are coupled to vehicles
with pintle hooks or hitches instead of a fifth wheel. As stated
previously, we are proposing that non-box trailers that are designed
for dedicated use with in-field operations related to logging and
mining be completely excluded from this Phase 2 trailer program. The
agencies believe that the operational capabilities of trailers designed
for these purposes could be compromised by the use of aerodynamic
devices or tires with lower rolling resistance. Additionally, the
agencies are proposing to exclude trailers designed for heavy-haul
applications and those that are not intended for highway use, as
follows:

--Trailers shorter than 35 feet in length with three axles, and all
trailers with four or more axles (including any lift axles)
--Trailers designed to operate at low speeds such that they are
unsuitable for normal highway operation
--Trailers designed to perform their primary function while stationary
--Trailers intended for temporary or permanent residence, office space,
or other work space, such as campers, mobile homes, and carnival
trailers
--Trailers designed to transport livestock
--Incomplete trailers that are sold to a secondary manufacturer for
modification to serve a purpose other than transporting freight, such
as for offices or storage \217\
---------------------------------------------------------------------------

    \217\ Secondary manufacturers who purchase incomplete trailers
and complete their construction to serve as trailers are subject to
the requirements of 40 CFR 1037.620.

    Where the criteria for exclusion identified above may be unclear
for specific trailer models, manufacturers would be encouraged to ask
the agencies to make a determination before production begins. The
agencies seek comments on these and any other trailer characteristics
that might make the trailers incompatible with highway use or would
restrict their typical operating speeds.
    Because the agencies are proposing that these trailers be excluded
from the program, we are not proposing to require manufacturers to
report to the agencies about these excluded trailers. We seek comments
on whether, in lieu of the exclusion of trailers from the program, the
agencies should instead exempt these trailers from the standards, but
still require reporting to the agencies in order to verify that a
manufacturer qualifies for an exemption. In that case, exempt trailers
would have some regulatory requirements (e.g., reporting); again,
excluded trailers would have no regulatory requirements under this
proposal. All other trailers would remain covered by the proposed
standards.
    As described earlier, the proposed program is based on the
expectation that manufacturers would be able to apply aerodynamic
devices and tire technologies to the vast majority of box trailers, and
these standards would be relatively stringent. We propose to categorize
trailers with functional components or work-performing equipment, and
trailers with certain design elements, that could partially interfere
with the installation or the effectiveness of some aerodynamic
technologies, as ``partial-aero'' box trailers. For example, some
trailer equipment by their placement or their need for operator access
might not be compatible with current designs of trailer skirts, but a
boat tail could be effective on that trailer in the early years of the
program. Similarly, a rear lift gate or roll-up rear door might not be
compatible with a current boat tail design, but skirts could be
effective. The proposed requirements for these trailers would the same
as their full-aero counterparts until MY 2027, at which time they would
continue to be subject to the MY 2024 standards. See 40 CFR 1037.107.
    For trailers for which no aerodynamic devices are practical, the
agencies are proposing design standards requiring LRR tires and ATI
systems. Trailers for which neither skirt/under-body devices nor rear-
end devices would be likely to be feasible fall into two categories:
non-box trailers and non-aero box trailers. We believe that there is
limited availability of aerodynamic technologies for non-box trailers
(for example, platform (flatbed) trailers, tank trailers, and container
chassis trailers). Also, for container chassis trailers, operational
considerations, such as stacking of the chassis trailers, impede
introduction of aerodynamic technologies. In addition, manufacturers of
these trailer types have little or no experience with aerodynamic
technologies designed for their products. Non-aero box trailers,
defined as those with equipment or design features that would preclude
both skirt/under-body and rear-end aerodynamic technologies (e.g., a
trailer with both a pull-out platform for side access and a rear lift
gate), would be subject to the same tire-only design standards as would
non-box trailers, based exclusively on the performance of tire and ATI
technologies.\218\
---------------------------------------------------------------------------

    \218\ The agencies are not aware of work-performing equipment
that would prevent the use of gap-reducing trailer devices on dry
vans of any length; thus dry vans with side and rear equipment could
qualify as ``non-aero'' trailers, even if the manufacturer could
install a gap-reducing device.
---------------------------------------------------------------------------

    We recognize that the shortest short box vans (i.e., less than 35
feet) are often pulled in tandem. Since these trailers make up the
majority of trailers in the short box van subcategories, we are not
proposing standards for short box dry and refrigerated vans based on
the use of rear devices. Thus, work-performing features on the rear of
the trailer (e.g., lift gates) would not impact a trailer's ability to
meet the full-aero short-box trailer standards. As a result, we are
proposing that all short box vans only be categorized as partial-aero
vans if they have work-performing side features (e.g., belly boxes). We
expect that partial-aero short dry van trailers would be able to adopt
front-side devices that would achieve the reduced standards.
Furthermore, some short box trailers that are not operated in tandem,
such as 40- or 48-foot trailers, could also be able to adopt rear-side
devices and achieve even greater reductions.
    Refrigerated short box vans are a special case in that they have
TRUs that limit the ability to apply aerodynamic technologies to the
front side of the trailers. Because of this, we are proposing to
classify the shortest refrigerated box vans (shorter than 35 feet) as
non-aero trailers if they are designed with work-performing side
features. Since these trailers may be pulled in tandem and since they
cannot adopt front-side aerodynamic devices, we propose that they meet
standards predicated on tire technologies only. Short box refrigerated
trailers 35 feet and longer would only qualify for non-aero standards
if they have work-

performing devices on both the side and rear of the trailer. See 40 CFR
1037.107.
    We request comment on these proposed provisions for excluding some
trailers from the program, including speed restrictions and physical
characteristics that would generally make them incompatible for highway
use. We also request comment on the proposed approach of applying less-
stringent standards to non-box, non-aero box, and partial-aero box
trailers.
(6) In-Use Standards
    Consistent with Section 202(a)(1) of the CAA, EPA is proposing that
the emissions standards apply for the useful life of the trailers.
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. Aerodynamic devices available today,
including trailer skirts, rear fairings, under-body devices, and gap-
reducing fairings, are designed to maintain their physical integrity
for the life of the trailer. In the absence of failures like
detachment, breakage, or misalignment, we expect that the aerodynamic
performance of the devices will not degrade appreciably over time and
that the projected CO2 and fuel consumption reductions will
continue for the life of the vehicle with no special maintenance
requirements. Because of this, EPA does not see a benefit to
establishing separate standards that would apply in-use for trailers.
EPA and NHTSA are proposing a regulatory useful life value for trailers
of 10 years, and thus the certification standards would apply in-use
for that period of time.\219\ See Section IV. F. (5) (a) for a
discussion of other factors related to trailer useful life.
---------------------------------------------------------------------------

    \219\ EPA may perform in-use testing of any vehicle subject to
the standards of this part, including trailers. For example, we may
test trailers to verify drag areas or other GEM inputs.
---------------------------------------------------------------------------

D. Feasibility of the Proposed Trailer Standards

    As discussed below, the agencies' initial determination, subject to
consideration of public comment, is that the standards presented in the
Section IV.C.2, are the maximum feasible and appropriate under the
agencies' respective authorities, considering lead time, cost, and
other factors. We summarize our analyses in this section, and describe
them in more detail in the Draft RIA (Chapter 2.10).
    Our analysis of the feasibility of the proposed CO2 and
fuel consumption standards is based on technology cost and
effectiveness values collected from several sources. Our assessment of
the proposed trailer program is based on information from:

--Southwest Research Institute evaluation of heavy-duty vehicle fuel
efficiency and costs for NHTSA,\220\
---------------------------------------------------------------------------

    \220\ Reinhart, T.E. (June 2015). Commercial Medium- and Heavy-
Duty Truck Fuel Efficiency Technology Study--Report #1. (Report No.
DOT HS 812 146). Washington, DC: National Highway Traffic Safety
Administration.
---------------------------------------------------------------------------

--2010 National Academy of Sciences report of Technologies and
Approaches to Reducing the Fuel Consumption of Medium- and Heavy-Duty
Vehicles,\221\
---------------------------------------------------------------------------

    \221\ Committee to Assess Fuel Economy Technologies for Medium-
and Heavy-Duty Vehicles; National Research Council; Transportation
Research Board (2010). Technologies and Approaches to Reducing the
Fuel Consumption of Medium- and Heavy-Duty Vehicles. (``The NAS
Report'') Washington, DC, The National Academies Press. Available
electronically from the National Academy Press Web site at http://www.nap.edu/catalog.php?record_id=12845.
---------------------------------------------------------------------------

--TIAX's assessment of technologies to support the NAS panel
report,\222\
---------------------------------------------------------------------------

    \222\ TIAX, LLC. ``Assessment of Fuel Economy Technologies for
Medium- and Heavy-Duty Vehicles,'' Final Report to National Academy
of Sciences, November 19, 2009.
---------------------------------------------------------------------------

--The analysis conducted by the Northeast States Center for a Clean Air
Future, International Council on Clean Transportation, Southwest
Research Institute and TIAX for reducing fuel consumption of heavy-duty
long haul combination tractors (the NESCCAF/ICCT study),\223\
---------------------------------------------------------------------------

    \223\ NESCCAF, ICCT, Southwest Research Institute, and TIAX.
Reducing Heavy-Duty Long Haul Combination Truck Fuel Consumption and
CO2 Emissions. October 2009.
---------------------------------------------------------------------------

--The technology cost analysis conducted by ICF for EPA,\224\ and
---------------------------------------------------------------------------

    \224\ ICF International. ``Investigation of Costs for Strategies
to Reduce Greenhouse Gas Emissions for Heavy-Duty On-Road
Vehicles.'' July 2010. Docket Number EPA-HQ-OAR-2010-0162-0283.
---------------------------------------------------------------------------

--Testing conducted by EPA.

    As an initial step in our analysis, we identified the extent to
which fuel consumption- and CO2-reducing technologies are in
use today.
    The technologies include those that reduce aerodynamic drag at the
front, back, and underside of trailers, tires with lower rolling
resistance, tire inflation technologies, and weight reduction through
component substitution. It should be noted that the agencies need not
and did not attempt to predict the exact future pathway of the
industry's response to the new standards, but rather demonstrated one
example of how compliance could reasonably occur, taking into account
cost of the standards (including costs of compliance testing and
certification), and needed lead time. We are proposing that full-aero
box trailer manufacturers have additional flexibility in meeting the
standards through averaging. The less complex standards proposed for
partial- and non-aero box and non-box trailers would still provide a
degree of technology choices that would meet their standards.
    For our feasibility analysis, we identified a set of technologies
to represent the range of those likely to be used in the time frame of
the rule. We then combined these technologies into packages of
increasing effectiveness in reducing CO2 and fuel
consumption and projected reasonable rates at which the evaluated
technologies and packages could be adopted across the trailer industry.
More details regarding our analysis can be found in Chapter <IP_ADDRESS> of
the draft RIA.
    The agencies developed the proposed CO2 and fuel
consumption standards for each stage of the program by combining the
projected effectiveness of trailer technologies and the projected
adoption rates for each trailer type. We evaluated these standards with
respect to the cost of these technologies, the emission reductions and
fuel consumption improvements achieved, and the lead-time needed to
deploy the technology at a given adoption rate.
    Unlike the other sectors covered by this Phase 2 rulemaking,
trailer manufacturers do not have experience certifying under the Phase
1 program. Moreover, a large fraction of the trailer industry is
composed of small businesses and very few of the largest trailer
manufacturers have the same resources available as manufacturers in the
other heavy-duty sectors. The standards have been developed with this
in mind, and we are confident the proposed standards can be achieved by
manufacturers who lack prior experience implementing such standards.
(1) Available Technologies
    Trailer manufacturers can design a trailer to reduce fuel
consumption and CO2 emissions by addressing the trailer's
aerodynamic drag, tire rolling resistance and weight. In this section
we outline the general trailer technologies that the agencies
considered in evaluating the feasibility of the proposed standards.
(a) Aerodynamic Drag Reduction
    Historically, the primary goal when designing the shape of box
trailers has been to maximize usable internal cargo volume, while
complying with regulatory size limits and minimizing construction
costs. This led to standard box trailers being rectangular. This basic
shape creates significant aerodynamic

drag and makes box trailers strong candidates for aerodynamic
improvements. Current bolt-on aerodynamic technologies for box trailers
are designed to create a smooth transition of airflow from the tractor,
around the trailer, and beyond the trailer.
    Table IV-3 lists general aerodynamic technologies that the EPA
SmartWay program has evaluated for use on box trailers and a
description of their intended impact. Several versions of each of these
technologies are commercially available and have seen increased
adoption over the past decade. Performance of these devices varies
based on their design, their location and orientation on the trailer,
and the vehicle speed. More information regarding the agencies' initial
assessment of these devices, including incremental costs is discussed
in Chapter 2.10 of the draft RIA.

          Table IV-3--Aerodynamic Technologies for Box Trailers
------------------------------------------------------------------------
                                        Example       Intended impact on
       Location on trailer           technologies        aerodynamics
------------------------------------------------------------------------
Front...........................  Front fairings and  Reduce cross-flow
                                   gap-reducing        through gap and
                                   fairings.           smoothly
                                                       transition
                                                       airflow from
                                                       tractor to the
                                                       trailer.
Rear............................  Rear fairings,      Reduce pressure
                                   boat tails and      drag induced by
                                   flow diffusers.     the trailer wake.
Underside.......................  Side fairings and   Manage flow of air
                                   skirts, and         under the trailer
                                   underbody devices.  to reduce
                                                       turbulence,
                                                       eddies and wake.
------------------------------------------------------------------------

    As mentioned previously, SmartWay-verified technologies are
evaluated on 53-foot dry vans. However, the CO2- and fuel
consumption-reducing potential of some aerodynamic technologies
demonstrated on 53-foot dry vans can be translated to refrigerated vans
and box trailers in lengths different than 53 feet and some fleets have
opted to add trailer skirts to their refrigerated vans and 28-foot
trailers (often called ``pups''). In addition, some side skirts have
been adapted for non-box trailers (e.g., tankers, platforms, and
container chassis), and have shown potential for large reductions in
drag. At this time, however, non-box trailer aerodynamic devices are
not widely available, with many still at the prototype stage. The
agencies encourage commenters to provide more information and data
related to the effectiveness of technologies applied to trailers other
than 53-foot dry and refrigerated vans.
    ``Boat tail'' devices, applied to the rear of a trailer, are
typically designed to collapse flat as the trailer rear doors are
opened. If the tail structure can remain in the collapsed configuration
when the doors are closed, the benefit of the device is lost. The
agencies request comment on whether we should require that trailer
manufacturers using such devices for compliance with the proposed
standards only use designs that automatically deploy when the vehicle
is in motion.
    The agencies are aware that physical characteristics of some box
trailers influence the technologies that can be applied. For instance,
the TRUs on refrigerated vans are located at the front of the trailer,
which prohibits the use of current gap-reducers. Similarly, drop deck
dry vans have lowered floors between the landing gear and the trailer
axles that limit the ability to use side skirts. The agencies
considered the availability and limitations of aerodynamic technologies
for each trailer type evaluated in our feasibility analysis of the
proposed and alternative standards.
(b) Tire Rolling Resistance
    On a typical Class 8 long-haul tractor-trailer, over 40 percent of
the total energy loss from tires is attributed to rolling resistance
from the trailer tires.\225\ Trailer tire rolling resistance values
collected by the agencies for Phase 1 indicate that the average
coefficient of rolling resistance (CRR) for new trailer
tires was 6.0 kg/ton. This value was applied for the standard trailer
used for tractor compliance in the Phase 1 tractor program. For Phase
2, the agencies consider all trailer tires with CRR values
below 6.0 kg/ton to be ``lower rolling resistance'' (LRR) tires. For
reference, a trailer tire that qualifies as a SmartWay-verified tire
must meet a CRR value of 5.1 kg/ton, a 15 percent
CRR reduction from the trailer tire identified in Phase 1.
Our research of rolling resistance indicates an additional
CRR reduction of 15 percent or more from the SmartWay
verification threshold is possible with tires that are available in the
commercial market today.
---------------------------------------------------------------------------

    \225\ ``Tires & Truck Fuel Economy: A New Perspective'', The
Tire Topic Magazine, Special Edition Four, 2008, Bridgestone
Firestone, North American Tire, LLC. Available online: http://www.trucktires.com/bridgestone/us_eng/brochures/pdf/08-Tires_and_Truck_Fuel_Economy.pdf.
---------------------------------------------------------------------------

    For this proposal, the agencies are proposing to use the same
rolling resistance baseline value of 6.0 kg/ton for all trailer
subcategories. We request comment on the appropriateness of 6.0 kg/ton
as the proposed CRR threshold for all regulated trailers.
Specifically, the agencies would like more information on current
adoption rates of and CRR values for models of LRR tires
currently in use on short box trailers and the various non-box
trailers.
    Similar to the case of tractor tires, LRR tires are available as
either dual or as single wide-based tires for trailers. Single wide-
based tires achieve CRR values that are similar to their
dual counterparts, but have an added benefit of weight reduction, which
can be an attractive option for trailers that frequently maximize cargo
weight. See Section IV.D.1.d below.
(c) Tire Pressure Systems
    The inflation pressure of tires also impacts the rolling
resistance. Tractor-trailers operating with all tires under-inflated by
10 psi have been shown to increase fuel consumed by up to 1
percent.\226\ Tires can gradually lose pressure from small punctures,
leaky valves or simply diffusion through the tire casing. Changes in
ambient temperature can also have an effect on tire pressure. Trailers
that remain unused for long periods of time between hauls may
experience any of these conditions. A 2003 FMCSA report found that
nearly 1 in 5 trailers had at least 1 tire under-inflated by 20 psi or
more. If drivers or fleets are not diligent about checking and
attending to under-inflated tires, the trailer may have much higher
rolling resistance and much higher CO2 emissions and fuel
consumption.
---------------------------------------------------------------------------

    \226\ ``Tire Pressure Systems--Confidence Report''. North
American Council for Freight Efficiency. 2013. Available online:
http://nacfe.org/wp-content/uploads/2014/01/TPS-Detailed-Confidence-Report1.pdf.
---------------------------------------------------------------------------

    Tire pressure monitoring (TPM) and automatic tire inflation (ATI)
systems are designed to address under-inflated tires. Both systems
alert drivers if a tire's pressure drops below its set point. TPM
systems are simpler and merely monitor tire pressure. Thus, they
require user-interaction to re inflate to the appropriate pressure.
Today's ATI systems, on the other hand, typically

take advantage of trailers' air brake systems to supply air back into
the tires (continuously or on demand) until a selected pressure is
achieved. In the event of a slow leak, ATI systems have the added
benefit of maintaining enough pressure to allow the driver to get to a
safe stopping area. The agencies believe TPM systems cannot
sufficiently guarantee the proper inflation of tires due to the
inherent user-interaction required. Therefore, ATI systems are the only
pressure systems the agencies are proposing to recognize in Phase 2.
    Benefits of ATI systems in individual trailers vary depending on
the base level of maintenance already performed by the driver or fleet,
as well as the number of miles the trailer travels. Trailers that are
well maintained or that travel fewer miles will experience less
benefits from ATI systems compared to trailers that often drive with
poorly inflated tires or log many miles. The agencies believe ATI
systems can provide a CO2 and fuel consumption benefit to
most trailers. With ATI use, trailers that have lower annual vehicle
miles traveled (VMT) due to long periods between uses would be less
susceptible to low tire pressures when they resume activity. Trailers
with high annual VMT would experience the fuel savings associated with
consistent tire pressures. Automatic tire inflation systems could
provide a CO2 and fuel consumption savings of 0.5-2.0
percent, depending on the degree of under-inflation in the trailer
system. See Section IV.D.3.d below for discussion of our estimates of
these factors, as well as estimates of the degree of adoption of ATI
systems prior to and at various points in the phase-in of the proposed
program.
    The use of ATI systems can result in cost savings beyond reducing
fuel costs. For example, drivers and fleets that diligently maintain
their tires would spend less time and money to inspect each tire. A
2011 FMCSA estimated under-inflation accounts for one service call per
year and increases tire procurement costs 10 to 13 percent. The study
found that total operating costs can increase by $600 to $800 per year
due to under-inflation.\227\
---------------------------------------------------------------------------

    \227\ TMC Future Truck Committee Presentation ``FMCSA Tire
Pressure Monitoring Field Operational Test Results,'' February 8,
2011.
---------------------------------------------------------------------------

(d) Weight Reduction
    Reduction in trailer tare (i.e., empty) weight can lead to fuel
efficiency reductions in two ways. For applications where payload is
not limited by weight restrictions, the overall weight of the tractor
and trailer would be reduced and would lead to improved fuel
efficiency. For applications where payload is limited by weight
restrictions, the lower trailer weight would allow additional payload
to be transported during the truck's trip, so emissions and fuel
consumption on a ton-mile basis would decrease. There are weight
reduction opportunities for trailers in both the structural components
and in the wheels/tires. Material substitution (e.g., replacing steel
with aluminum or lighter-weight composites) is feasible for components
such as roof bows, side and corner posts, cross members, floor joists,
floors, and van sidewalls. Similar material substitution is feasible
for wheels (e.g., substituting aluminum for steel). Weight can also be
reduced through the use of single wide-based tires replacing two dual
tires.
    Lower weight is a desired trailer attribute for many customers, and
most trailer manufacturers offer options that reduce weight to some
degree. Some of these manufacturers, especially box van makers, market
trailers with lower-weight major components, such as light-weight
composite van sidewalls or aluminum floors, especially to customers
that expect to frequently reach regulatory weight limits (i.e., ``weigh
out'') and are willing to pay a premium for the ability to increase
cargo weight without exceeding overall vehicle weight. Alternatively,
manufacturers that primarily design trailers for customers that do not
have weight limit concerns (i.e., their payloads frequently fill the
available trailer cargo space before the weight limit is reached, or
``cube out''), or for customers that have smaller budgets, may continue
to design trailers based on traditional, heavier materials, such as
wood and steel.
    There is no clear ``baseline'' for current trailer weight against
which lower-weight designs could be compared for regulatory purposes.
For this reason, the agencies do not believe it would be appropriate or
fair across the industry to apply overall weight reductions toward
compliance. However, the agencies do believe it would be appropriate to
allow a manufacturer to account for weight reductions that involve
substituting very specific, traditionally heavier components with
lower-weight options that are not currently widely adopted in the
industry. We discuss how we apply weight reduction in developing the
standards in Section IV. D. (2)(d) below.
(2) Technological Basis of the Standards
    The analysis below presents one possible set of technology designs
by which trailer manufacturers could reasonably achieve the goals of
the program on average. However, in practice, trailer manufacturers
could choose different technologies, versions of technologies, and
combinations of technologies that meet the business needs of their
customers while complying with this proposed program.
    Much of our analysis is performed for box trailers, which have the
most stringent proposed standards. As mentioned previously, we have
separate standards for short and long box vans, and a trailer length of
50 feet is proposed as the cut-point to distinguish the two length
categories. For the purpose of this analysis, long trailers are
represented by 53-foot vans and short trailers are represented by
single, 28-foot (``pup'') vans. These trailer lengths make up the
largest fraction of the vans in the two categories. The agencies
recognize that many 28-foot short vans are operated in tandem. However,
these trailers are sold individually, and require a ``dolly'', often
sold by a separate manufacturer, to connect the trailers for tandem
operation.
    In addition, the other trailer types considered short vans in this
proposal (e.g., 40-foot and 48-foot) typically operate as single
trailers. To minimize complexity, we are proposing that 28-foot
trailers represent all short refrigerated and dry vans for both
compliance and for this feasibility analysis. This means that
manufacturers would not need to perform tests (or report device
manufacturers' test data) of the performance of devices for each
trailer length in the short van category. Although this approach would
provide a conservative estimate of actual CO2 emissions and
fuel consumption reductions for the short van category, the agencies
believe that the need to avoid an overly complex compliance program
justifies this approach. We request comment on this approach to
evaluating short box trailers.
(a) Aerodynamic Packages
    In order to evaluate performance and cost of the aerodynamic
technologies discussed in the previous section, the agencies identified
``packages'' of individual or combined technologies that are being sold
today on box trailers. The agencies also identified distinct
performance levels (i.e., bins) for these technologies based on EPA's
aerodynamic testing. The agencies recognize that there are other
technology options that have similar performance. We chose the
technologies presented here based on their current adoption rates and
effectiveness in reducing CO2 and fuel consumption.

    Bin I represents a base trailer with no aerodynamic technologies
added. There is no cost associated with this bin. Bin II achieves small
reductions in CO2 and fuel consumption. This bin includes a
gap reducing fairing added to a long dry van or a skirt added to a solo
short dry van.\228\ Bin III includes devices that would achieve
SmartWay's verification threshold of four percent at cruise speeds.
Some basic skirts and boat tails would achieve these levels of
reductions for long box trailers. A gap reducer and a basic skirt on a
short dry van would meet this level of performance. Bin IV technologies
are more effective, single aerodynamic devices for long box trailers,
including advanced skirts or boat tails, that achieve larger reductions
in drag than the technologies in Bin III. The combination of an
advanced skirt and gap reducer on a short dry van are also expected to
achieve this bin.
---------------------------------------------------------------------------

    \228\ The agencies recognize that many 28-foot pup trailers are
often operated in tandem. However, we are regulating and evaluating
short dry vans as solo trailers since they are sold individually and
the short box regulatory subcategories also include trailer sizes
not often operated in tandem (e.g., 40-foot and 48-foot trailers).
---------------------------------------------------------------------------

    Bin V levels of performance were not observed in EPA's aerodynamic
testing for short box trailers. It is possible that a gap reducer,
skirt, and boat tail could achieve this performance, but boat tails are
not feasible for 28-foot trailers operated in tandem unless the trailer
is located in the rear position. For this analysis, the agencies only
evaluated solo pup trailers and, therefore, did not evaluate any
technologies for short box trailers beyond Bin IV. For this proposed
rulemaking, we believe a Bin V level of performance can be achieved for
long box trailers by either highly effective single devices or by
applying a combination of basic boat tails and skirts. We do not
currently have data for a single aerodynamic device that fits this bin
and we evaluated it as a combination of a basic tail and skirt. Bin VI
combines advanced skirts and boat tail technologies on long box
trailers. This bin is expected to include many technologies that
qualify for SmartWay's ``Elite'' designation.
    Bin VII represents an optimized system of technologies that work
together to synergistically address each of the main areas of drag and
achieves aerodynamic improvements greater than SmartWay's ``Elite''
designation. We are representing Bin VII with a gap reducer, and
advanced tail and skirt. Bin VIII is designed to represent aerodynamic
technologies that may become available in the future, including
aerodynamic devices yet to be designed or approaches that would
incorporate changes to the construction of trailer bodies. We have not
analyzed this final bin in terms of effectiveness or cost, but are
including it to account for future advancements in trailer
aerodynamics.
    For this proposal, aerodynamic performance is evaluated using a
vehicle's aerodynamic drag area, CDA. EPA collected
aerodynamic test data for several tractor-trailer configurations,
including 53-foot dry vans and 28-foot dry van trailers with many of
these technology packages. The agencies developed bins, somewhat
similar to the aerodynamic bins in the Phase 1 and proposed Phase 2
tractor programs, based on results from our test program. However,
unlike the tractor program, we grouped the technologies by changes in
CDA (or ``delta CDA'') rather than by absolute
values. In other words, each bin would comprise aerodynamic
technologies that provide similar improvements in drag. This delta
CDA classification methodology, which measures improvement
in performance relative to a baseline, is similar to the SmartWay
technology verification program with which most trailer manufacturers
are familiar.
    Table IV-4 illustrates the bin structure that the agencies are
proposing as the basis for compliance. The table shows example
technology packages that might be included in each bin based on EPA's
testing of 53-foot dry vans and solo 28-foot dry vans. The agencies
believe these bins apply to other box trailers (refrigerated vans and
lengths other than 28 and 53 feet), which will be described in more
detail in Section IV.D.3.b. These bins cover a wide enough range of
delta CDAs to account for the uncertainty seen in EPA's
aerodynamic testing program due to procedure variability, the use of
different test methods, or different models of tractors, trailers and
devices. A more detailed description of the development of these bins
can be found in the draft RIA, Chapter 2.10. We welcome comments and
additional data that may support or suggest changes to these bins.

                     Table IV-4--Technology Bins Used To Evaluate Trailer Benefits and Costs
----------------------------------------------------------------------------------------------------------------
                                                                                Example technologies
                Bin                    Delta CdA     Average delta ---------------------------------------------
                                                          CDA          53-foot dry van        28-foot dry van
----------------------------------------------------------------------------------------------------------------
Bin I.............................          < 0.09             0.0  No Aero Devices......  No Aero Devices.
Bin II............................       0.10-0.19             0.1  Gap Reducer..........  Skirt.
Bin III...........................       0.20-0.39             0.3  Basic Skirt or Basic   Skirt + Gap Reducer.
                                                                     Tail.
Bin IV............................       0.40-0.59             0.5  Advanced Skirt or      Adv. Skirt + Gap
                                                                     Tail.                  Reducer.
Bin V.............................       0.60-0.79             0.7  Basic Combinations...
Bin VI............................       0.80-1.19             1.0  Advanced Combinations  .....................
                                                                     (including SmartWay
                                                                     Elite).
Bin VII...........................       1.20-1.59             1.4  Optimized              .....................
                                                                     Combinations.
Bin VIII..........................           > 1.6             1.8  Changes to Trailer     .....................
                                                                     Construction.
----------------------------------------------------------------------------------------------------------------
Note: A blank cell indicates a zero or NA value in this table.

    The agencies used EPA's Greenhouse gas Emissions Model (GEM)
vehicle simulation tool to conduct this analysis. See Section F.1 below
for more about GEM. Within GEM, the aerodynamic performance of each
trailer subcategory is evaluated by subtracting the delta
CDA shown in Table IV-4 from the CDA value
representing a specific standard tractor pulling a zero-technology
trailer. The agencies chose to model the zero-technology long box dry
van using a CDA value of 6.2 m\2\ (the average
CDA from EPA's coastdown testing). For long box refrigerated
vans, a two percent reduction in CDA was assumed to account
for the aerodynamic benefit of the TRU at the front of the trailer.
Short box dry vans also received a two percent lower CDA
value compared to its 53-foot counterpart, consistent with the
reduction observed in EPA's wind tunnel testing. The CDA
value assigned to the refrigerated short box vans was an

additional two percent lower than the short box dry van. Non-aero box
trailers are modeled as short box dry vans. The trailer subcategories
that have design standards (i.e., non-box and non-aero box trailers) do
not have numerical standards to meet, but they were evaluated in this
feasibility analysis in order to quantify the benefits of including
them in the program. Non-aero box trailers are modeled as short dry
vans. Non-box trailers, which are modeled as flatbed trailers, were
assigned a drag area of 4.9 m\2\, as was done in the Phase 1 tractor
program for low roof day cabs. Table IV-5 illustrates the Bin I drag
areas (CDA) associated with each trailer subcategory.

    Table IV-5--Baseline CDA Values Associated With Aerodynamic Bin I
                       [Zero trailer technologies]
------------------------------------------------------------------------
                   Trailer subcategory                        Dry van
------------------------------------------------------------------------
Long Dry Van............................................             6.2
Short Dry Van...........................................             6.1
Long Ref. Van...........................................             6.1
Short Ref. Van..........................................             6.0
Non-Aero Box............................................             6.1
Non-Box.................................................             4.9
------------------------------------------------------------------------

(b) Tire Rolling Resistance
    Similar to the proposed Phase 2 tractor and vocational vehicle
programs, the agencies are proposing a tire program based on adoption
of lower rolling resistance tires. Feedback from several box trailer
manufacturers indicates that the standard tires offered on their new
trailers are SmartWay-verified tires (i.e., CRR of 5.1 kg/
ton or better). An informal survey of members from the Truck Trailer
Manufacturers Association (TTMA) indicates about 35 percent of box
trailers sold today have SmartWay tires.\229\ While some trailers
continue to be sold with tires of higher rolling resistances, the
agencies believe most box trailer tires currently achieve the Phase 1
trailer tire CRR of 6.0 kg/ton or better.
---------------------------------------------------------------------------

    \229\ Truck Trailer Manufacturers Association letter to EPA.
Received on October 16, 2014. Docket EPA-HQ-OAR-2014-0827.
---------------------------------------------------------------------------

    The agencies evaluated two levels of tire performance for this
proposal beyond the baseline trailer tire rolling resistance level
(TRRL) of 6.0 kg/ton. The first performance level was set at the
criteria for SmartWay-verification for trailer tires, 5.1 kg/ton, which
is a 15 percent reduction in CRR from the baseline. As
mentioned previously, several tire models available today achieve
rolling resistance values well below the present SmartWay threshold.
Given the multiple year phase-in of the standards, the agencies expect
that tire manufacturers will continue to respond to demand for more
efficient tires and will offer increasing numbers of tire models with
rolling resistance values significantly better than today's typical LRR
tires. In this context, we believe it is reasonable to expect a large
fraction of the trailer industry could adopt tires with rolling
resistances at a second performance level that would achieve an
additional eight percent reduction in rolling resistance (a 22 percent
reduction from the baseline tire), especially in the later stages of
the program. The agencies project the CRR for this second
level of performance to be a value of 4.7 kg/ton.
    The agencies evaluated these three tire rolling resistance levels,
summarized in Table IV-6, in the feasibility analysis of the following
sections. GEM simulations that apply Level 1 and 2 tires result in
CO2 and fuel consumption reductions of two and three percent
from the baseline tire, respectively. It should be noted that these
levels are for the feasibility analysis only. For compliance,
manufacturers would have the option to use tires with any rolling
resistance and would not be limited to these TRRLs.

 Table IV-6--Summary of Trailer Tire Rolling Resistance Levels Evaluated
------------------------------------------------------------------------
                                                                CRR (kg/
                Tire rolling resistance level                     ton)
------------------------------------------------------------------------
Baseline.....................................................        6.0
Level 1......................................................        5.1
Level 2......................................................        4.7
------------------------------------------------------------------------

(c) Automatic Tire Inflation Systems
    NHTSA and EPA recognize the role of proper tire inflation in
maintaining optimum tire rolling resistance during normal trailer
operation. For this proposal, rather than require performance testing
of ATI systems, the agencies are proposing to recognize the benefits of
ATI systems with a single default reduction for manufacturers that
incorporate ATI systems into their trailer designs. Based on
information available today, we believe that there is a narrow range of
performance among technologies available and among systems in typical
use. We propose to assign a 1.5 percent reduction in CO2 and
fuel consumption for all trailers that implement ATI systems, based on
information available today.\230\ We believe the use of these systems
can consistently ensure that tire pressure and tire rolling resistance
are maintained. We selected the levels of the proposed trailer
standards with the expectation that a high rate of adoption of ATI
systems would occur across all on-highway trailers and during all years
of the phase-in of the program. See Section IV.D.3.d below for
discussion of our estimates of these factors, as well as estimates of
the degree of adoption of ATI systems prior to and at various points in
the phase-in of the proposed program. The informal survey of members
from the Truck Trailer Manufacturers Association (TTMA) indicates about
40 percent of box trailers sold today have ATI systems.\231\
---------------------------------------------------------------------------

    \230\ See the Chapter <IP_ADDRESS> of the draft RIA.
    \231\ Truck Trailer Manufacturers Association letter to EPA.
Received on October 16, 2014. Docket EPA-HQ-OAR-2014-0827
---------------------------------------------------------------------------

(d) Weight Reduction
    The agencies are proposing compliance provisions that would limit
the weight-reduction options to the substitution of specified
components that can be clearly isolated from the trailer as a whole.
For this proposal, the agencies have identified several conventional
components with available lighter-weight substitutes (e.g.,
substituting conventional dual tires mounted on steel wheels with wide-
based single tires mounted on aluminum wheels). We are proposing values
for the associated weight-related savings that would be applied with
these substitutions for compliance. The proposed component
substitutions and their associated weight savings are presented in the
draft RIA, Chapter <IP_ADDRESS> and in proposed 40 CFR 1037.515. We believe
that the initial cost of these component substitutions is currently
substantial enough that only a relatively small segment of the industry
has adopted these technologies today.
    The agencies recognize that when weight reduction is applied to a
trailer, some operators will replace that saved weight with additional
payload. To account for this in EPA's GEM vehicle simulation tool, it
is assumed that one-third of the weight reduction will be applied to
the payload. For tractor-trailers simulated in GEM, it takes a weight
reduction of nearly 1,000 lbs before a one percent fuel savings is
achieved. The component substitutions identified by the agencies result
in weight reductions of less than 500 lbs, yet can cost over $1,000.
The agencies believe that few trailer manufacturers would apply weight
reduction solely as a means of achieving reduced fuel consumption and
CO2 emissions. Therefore, we are proposing standards that
could be met without reducing weight--that is, the compliance path set

out by the agencies for the proposed standards does not include weight
reduction. However, we are proposing to offer weight reduction as an
option for box trailer manufacturers who wish to apply it to some of
their trailers as part of their compliance strategy.
    The agencies have identified 11 common trailer components that have
lighter weight options available (see 40 CFR 1037.515)
232 233 234 235 Manufacturers that adopt these technologies
would sum the associated weight reductions and apply those values in
GEM. As mentioned previously, we are restricting the weight reduction
options to those listed in 40 CFR 1037.515. We are requesting comment
on the appropriateness of the specified weight reductions from
component substitution. In addition, we seek weight and cost data
regarding additional components that could be offered as specific
weight reduction options. The agencies request that any such components
be applicable to most box trailers, and that the reduced weight option
not currently be in common use.
---------------------------------------------------------------------------

    \232\ Scarcelli, Jamie. ``Fuel Efficiency for Trailers''
Presented at ACEEE/ICCT Workshop: Emerging Technologies for Heavy-
Duty Vehicle Fuel Efficiency, Wabash National Corporation. July 22,
2014.
    \233\ ``Weight Reduction: A Glance at Clean Freight
Strategies'', EPA SmartWay. EPA420F09-043. Available at: http://permanent.access.gpo.gov/gpo38937/EPA420F09-043.pdf.
    \234\ Memorandum dated June 2015 regarding confidential weight
reduction information obtained during SBREFA Panel. Docket EPA-HQ-
OAR-2014-0827.
    \235\ Randall Scheps, Aluminum Association, ``The Aluminum
Advantage: Exploring Commercial Vehicles Applications,'' presented
in Ann Arbor, Michigan, June 18, 2009.
---------------------------------------------------------------------------

(3) Effectiveness, Adoption Rates, and Costs of Technologies for the
Proposed Standards
    The agencies evaluated the technologies above as they apply to each
of the trailer subcategories. The next sections describe the
effectiveness, adoption rates and costs associated with these
technologies. The effectiveness and adoption rates are then used to
derive the proposed standards.
(a) Zero-Technology Baseline Tractor-Trailer Vehicles
    The regulatory purpose of EPA's heavy-duty vehicle compliance tool,
GEM, is to combine the effects of trailer technologies through
simulation so that they can be expressed as g/ton-mile and gal/1000
ton-mile and thus avoid the need for direct testing of each trailer
model being certified. The proposed trailer program has separate
standards for each trailer subcategory, and a unique tractor-trailer
vehicle was chosen to represent each subcategory for compliance. In the
Phase 2 update to GEM, each trailer subcategory is modeled as a
particular trailer being pulled by a standard tractor depending on the
physical characteristics and use pattern of the trailer. Table IV-7
highlights the relevant vehicle characteristics for the zero-technology
baseline of each subcategory. Baseline trailer tires are used, and the
drag area, which is a function of the aerodynamic characteristics of
both the tractor and trailer, is set to the Bin I values shown
previously in Table IV-5. Weight reduction and ATI systems are not
applied in these baselines. Chapter 2.10 of the draft RIA provides a
detailed description of the development of these baseline tractor-
trailers.
    The agencies chose to consistently model a Class 8 tractor across
all trailer subcategories. We recognize that Class 7 tractors are
sometimes used in certain applications. However, we believe Class 8
tractors are more widely available, which will make it easier for
trailer manufacturers to obtain a qualified tractor if they choose to
perform trailer testing. We request comment on the use of Class 8
tractors as part of the tractor-trailer vehicles used in the compliance
simulation as well as performance testing. We ask that commenters
include data, where available, related to the current use and
availability of Class 7 and 8 tractors with respect to the trailer
types in each trailer subcategory.

                                  Table IV--7 Characteristics of the Zero-Technology Baseline Tractor-Trailer Vehicles
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Dry van
                                             Refrigerated van                Non-aero box           Non-box
                                 -----------------------------------------------------------------------------------------------------------------------
Trailer Length..................  Long..............  Short.............  Long..............  Short.............  All Lengths.......  All Lengths
Tractor Class...................  Class 8...........  Class 8...........  Class 8...........  Class 8...........  Class 8...........  Class 8
Tractor Cab Type................  Sleeper...........  Day...............  Sleeper...........  Day...............  Day...............  Day
Tractor Roof Height.............  High..............  High..............  High..............  High..............  High..............  Low
Engine..........................  2018 MY 15L,......  2018 MY 15L,......  2018 MY 15L,......  2018 MY 15L,......  2018 MY 15L,......  2018 MY 15L,
                                  455 HP............  455 HP............  455 HP............  455 HP............  455 HP............  455 HP
Frontal Area (m\2\).............  10.4..............  10.4..............  10.4..............  10.4..............  10.4..............  6.9
Drag Area, CDA (m\2\)...........  6.2...............  6.1...............  6.1...............  6.0...............  6.1...............  4.9
Steer Tire RR (kg/ton)..........  6.54..............  6.54..............  6.54..............  6.54..............  6.54..............  6.54
Drive Tire RR (kg/ton)..........  6.92..............  6.92..............  6.92..............  6.92..............  6.92..............  6.92
Trailer Tire RR (kg/ton)........  6.00..............  6.00..............  6.00..............  6.00..............  6.00..............  6.00
Total Weight (kg)...............  31,978............  21,028............  33,778............  22,828............  21,028............  29,710
Payload (tons)..................  19................  10................  19................  10................  10................  19
ATI System Use..................  0.................  0.................  0.................  0.................  0.................  0
Weight Reduction (lb)...........  0.................  0.................  0.................  0.................  0.................  0
Drive Cycle Weightings..........  ..................  ..................  ..................  ..................  ..................  ..................
65-MPH Cruise...................  86%...............  64%...............  86%...............  64%...............  64%...............  64%
55-MPH Cruise...................  9%................  17%...............  9%................  17%...............  17%...............  17%
Transient Driving...............  5%................  19%...............  5%................  19%...............  19%...............  19%
--------------------------------------------------------------------------------------------------------------------------------------------------------

(b) Effectiveness of Technologies
    The agencies are proposing to recognize trailer improvements via
four performance parameters: aerodynamic drag reduction, tire rolling
resistance reduction, the adoption of ATI systems, and by substituting
specific weight-reducing components. Table IV-8 summarizes the
performance levels for each of these parameters based on the technology
characteristics outlined in Section IV. D. (2) .

   Table IV--8 Performance Parameters for the Proposed Trailer Program
------------------------------------------------------------------------

------------------------------------------------------------------------
Aerodynamics (Delta CDA, m\2\):
  Bin I...................................  0.0.
  Bin II..................................  0.1.
  Bin III.................................  0.3.
  Bin IV..................................  0.5.
  Bin V...................................  0.7.
  Bin VI..................................  1.0.
  Bin VII.................................  1.4.
  Bin VIII................................  1.8.
Tire Rolling Resistance (CRR, kg/ton):
  Tire Baseline...........................  6.0.
  Tire Level 1............................  5.1.
  Tire Level 2............................  4.7.
Tire Inflation System (% reduction):
  ATI System..............................  1.5.
Weight Reduction (lbs):
  Weight..................................  1/3 added to payload,
                                             remaining reduces overall
                                             vehicle weight.
------------------------------------------------------------------------

    These performance parameters have different effects on each trailer
subcategory due to differences in the simulated trailer
characteristics. Table IV-9 shows the agencies' estimates of the
effectiveness of each parameter for the four box trailer subcategories.
Each technology was evaluated using the baseline parameter values for
the other technology categories. For example, each aerodynamic bin was
evaluated using the baseline tire (6.0 kg/ton) and the baseline weight
reduction option (zero lbs). The table shows that aerodynamic
improvements offer the largest potential for CO2 emissions
and fuel consumption reductions, making them relatively effective
technologies.

 Table IV-9--Effectiveness (Percent CO2 and Fuel Savings From Baseline) of Technologies for the Proposed Trailer
                                                     Program
----------------------------------------------------------------------------------------------------------------
                                                              Dry van                    Refrigerated van
         Aerodynamics           Delta CDA (m\2\) ---------------------------------------------------------------
                                                       Long            Short           Long            Short
----------------------------------------------------------------------------------------------------------------
Bin I.........................  0.0.............              0%              0%              0%              0%
Bin II........................  0.1.............              -1              -1              -1              -1
Bin III.......................  0.3.............              -2              -2              -2              -2
Bin IV........................  0.5.............              -3              -4              -3              -3
Bin V.........................  0.7.............              -5              -5              -5              -5
Bin VI........................  1.0.............              -7              -7              -7              -7
Bin VII.......................  1.4.............             -10             -10              -9             -10
Bin VIII......................  1.8.............             -13             -13             -12             -12
----------------------------------------------------------------------------------------------------------------
Tire Rolling Resistance         CRR (kg/ton)....              Dry van
                                        Refrigerated van
                                                 ---------------------------------------------------------------
                                                            Long           Short            Long           Short
----------------------------------------------------------------------------------------------------------------
Baseline......................  6.0.............               0               0               0               0
Level 1.......................  5.1.............              -2              -1              -2              -1
Level 2.......................  4.7.............              -3              -2              -3              -2
----------------------------------------------------------------------------------------------------------------
Weight Reduction                Weight (lb).....              Dry van
                                        Refrigerated van
                                                 ---------------------------------------------------------------
                                                            Long           Short            Long           Short
----------------------------------------------------------------------------------------------------------------
Baseline......................  0.0.............             0.0             0.0             0.0             0.0
Al. Dual Wheels...............  168.............            -0.2            -0.3            -0.2            -0.3
Upper Coupler.................  280.............            -0.3              -1            -0.3              -1
Suspension....................  430.............            -0.5              -1            -0.5              -1
Al. Single Wide...............  556.............              -1              -1              -1              -1
----------------------------------------------------------------------------------------------------------------

(c) Reference Tractor-Trailer To Evaluate Benefits and Costs
    In order to evaluate the benefits and costs of the proposed
standards, it is necessary to establish a reference point for
comparison. As mentioned previously, the technologies described in
Section IV. D. (2) exist in the market today, and their adoption is
driven by available fuel savings as well as by the voluntary SmartWay
Partnership and California's tractor-trailer requirements. For this
proposal, the agencies identified reference case tractor-trailers for
each trailer subcategory based on the technology adoption rates we
project would exist if this proposed trailer program was not
implemented.
    We project that by 2018, absent further California regulation,
EPA's SmartWay program and these research programs will result in about
20 percent of 53-foot dry and refrigerated vans adopting basic
SmartWay-level aerodynamic technologies (meeting SmartWay's four
percent verification level and Bin III from Table IV-5), 30 percent
adopting more advanced aerodynamic technologies at the five percent
SmartWay-verification level (Bin IV from Table IV-5) and five percent
adding combinations of technologies (Bin V).236 237 238 In
addition, we project half of these 53' box trailers will be equipped
with SmartWay-verified tires (i.e., 5.1 kg/ton or better) and ATI
systems as well. The agencies project that market forces will drive an
additional one percent increase in adoption of the advanced SmartWay
and tire technologies each year through 2027. For analytical purposes,
the agencies assumed manufacturers of the shorter box trailers and
other trailer

subcategories would not adopt these technologies in the timeframe
considered and a zero-technology baseline is assumed. We are not
assuming weight reduction for any of the trailer subcategories in the
reference cases. Table IV-10 summarizes the reference case trailers for
each trailer subcategory.
---------------------------------------------------------------------------

    \236\ Truck Trailer Manufacturers Association letter to EPA.
Received on October 16, 2014. Docket EPA-HQ-OAR-2014-0827.
    \237\ Ben Sharpe (ICCT) and Mike Roeth (North American Council
for Freight Efficiency), ``Costs and Adoption Rates of Fuel-Saving
Technologies for Trailer in the North American On-Road Freight
Sector'', Feb 2014.
    \238\ Frost & Sullivan, ``Strategic Analysis of North American
Semi-trailer Advanced Technology Market'', Feb 2013.

  Table IV-10--Projected Adoption Rates and Average Performance Parameters for the Less Dynamic Reference Case
                                                    Trailers
----------------------------------------------------------------------------------------------------------------
           Technology                            Long box  dry & refrigerated vans                Short box, non-
-------------------------------------------------------------------------------------------------   aero box, &
                                                                                non-box
                                                                                trailers
           Model Year                  2018            2021            2024            2027      ---------------
                                                                                2018-2027
----------------------------------------------------------------------------------------------------------------
Aerodynamics:
    Bin I.......................             45%             41%             38%             35%            100%
    Bin II......................  ..............  ..............  ..............  ..............  ..............
    Bin III.....................              20              20              20              20  ..............
    Bin IV......................              30              34              37              40  ..............
    Bin V.......................               5               5               5               5  ..............
    Bin VI......................  ..............  ..............  ..............  ..............  ..............
    Bin VII.....................  ..............  ..............  ..............  ..............  ..............
    Bin VIII....................  ..............  ..............  ..............  ..............  ..............
        Average Delta CDA (m\2\)             0.2             0.3             0.3             0.3             0.0
         \a\....................
Tire Rolling Resistance:
    Baseline tires..............              50              47              43              40             100
    Level 1 tires...............              50              53              57              60  ..............
    Level 2 tires...............  ..............  ..............  ..............  ..............  ..............
        Average CRR (kg/ton) \a\            5.55            5.52            5.49            5.46             6.0
Tire Inflation:
    ATI.........................              50              53              57              60               0
        Average % Reduction \a\.             0.8             0.8             0.9             0.9             0.0
Weight Reduction (lbs):
    Weight \b\..................  ..............  ..............  ..............  ..............  ..............
----------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
\a\ Combines adoption rates with performance levels shown in Table IV-8.
\b\ Weight reduction was not projected for the reference case trailers.

    Also shown in Table IV-10 are average aerodynamic performance
(delta CDA), average tire rolling resistance
(CRR), and average reductions due to use of ATI and weight
reduction for each stage of the proposed program. These values indicate
the performance of theoretical average tractor-trailers that the
agencies project will be in use if no federal regulations were in place
for trailer CO2 and fuel consumption. The average tractor-
trailer vehicles serve as reference cases for each trailer subcategory.
The agencies provide a detailed description of the development of these
reference case vehicles in Chapter 2.10 in the draft RIA.
    Because the agencies cannot be certain about future trends, we also
considered a second reference case. This more dynamic reference case
reflects the possibility that absent a Phase 2 regulation, there will
be continuing adoption of technologies in the trailer market after 2027
that reduce fuel consumption and CO2 emissions. This case
assumes the research funded and conducted by the federal government,
industry, academia and other organizations will, after 2027, result the
adoption of some technologies beyond the levels required to comply with
existing regulatory and voluntary programs. One example of such
research is the Department of Energy Super Truck program which has a
goal of demonstrating cost-effective measures to improve the efficiency
of Class 8 long-haul freight trucks by 50 percent by 2015.\239\ This
reference case assumes that by 2040, 75 percent of new trailers will be
equipped with SmartWay-verified aerodynamic devices, low rolling
resistance tires, and ATI systems. Table IV-11 shows the agencies'
projected adoption rates of technologies in the more dynamic reference
case.
---------------------------------------------------------------------------

    \239\ Daimler Truck North America. SuperTruck Program Vehicle
Project Review. June 19, 2014. Docket EPA-HQ-OAR-2014-0827.

                      Table IV-11--Projected Adoption Rates and Average Performance Parameters for the More Dynamic Reference Case
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Technology                                                Long box dry & refrigerated vans                         Short box, non-
-----------------------------------------------------------------------------------------------------------------------------------------   aero box, &
                                                                                non-box
                                                                                trailers
                       Model year                              2018            2021            2024            2027            2040      ---------------
                                                                                2018-2027
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamics:
    Bin I...............................................             45%             41%             38%             35%             20%            100%
    Bin II..............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin III.............................................              20              20              20              20              20  ..............

    Bin IV..............................................              30              34              37              40              55  ..............
    Bin V...............................................               5               5               5               5               5  ..............
    Bin VI..............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VII.............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VIII............................................  ..............  ..............  ..............  ..............  ..............  ..............
        Average Delta C DA (m\2\) \a\...................             0.2             0.3             0.3             0.3             0.4             0.0
Tire Rolling Resistance:
    Baseline tires......................................              50              47              43              40              25             100
    Level 1 tires.......................................              50              53              57              60              75  ..............
    Level 2 tires.......................................  ..............  ..............  ..............  ..............  ..............  ..............
        Average CRR (kg/ton) \a\........................             5.6             5.5             5.5             5.5             5.3             6.0
Tire Inflation:
ATI.....................................................              50              53              57              60              75               0
        Average % Reduction \a\.........................             0.8             0.8             0.9             0.9             1.1             0.0
Weight Reduction (lbs):
    Weight \b\..........................................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
\a\ Combines adoption rates with performance levels shown in Table IV-8.
\b\ Weight reduction was not projected for the reference case trailers.

    The agencies applied the vehicle attributes from Table IV-7 and the
average performance values from Table IV-10 in the proposed Phase 2 GEM
vehicle simulation to calculate the CO2 emissions and fuel
consumption performance of the reference tractor-trailers. The results
of these simulations are shown in Table IV-12. We used these
CO2 and fuel consumption values to calculate the relative
benefits of the proposed standards. Note that the large difference
between the per ton-mile values for long and short trailers is due
primarily to the large difference in assumed payload (19 tons compared
to 10 tons) as seen in Table IV-7 and discussed further in the Chapter
2.10.3. The alternative reference case shown in Table IV-11 impacts the
long-term projections of benefits beyond 2027, which are analyzed in
Chapters 5-7 of the draft RIA.

           Table IV-12--CO2 Emissions and Fuel Consumption Results for the Reference Tractor-Trailers
----------------------------------------------------------------------------------------------------------------
                                                              Dry van                    Refrigerated van
                     Length                      ---------------------------------------------------------------
                                                       Long            Short           Long            Short
----------------------------------------------------------------------------------------------------------------
CO2 Emissions (g/ton-mile)......................              85             147              87             151
Fuel Consumption (gal/1000 ton-miles)...........          8.3497         14.4401          8.5462         14.8330
----------------------------------------------------------------------------------------------------------------

(d) Projected Technology Adoption Rates for the Proposed Standards
    As described in Section IV. E., the agencies evaluated several
alternatives for the proposed trailer program. Based on our analysis,
and current information, the agencies are proposing the alternative we
believe reflects the agencies' respective statutory authorities. The
agencies are also considering an accelerated alternative with less lead
time, requiring the same incremental stringencies for the proposed
program, but becoming effective three years earlier. The agencies
believe this alternative has the potential to be the maximum feasible
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. EPA and NHTSA are seriously considering this accelerated
alternative in whole or in part for the trailer segment. In other
words, the agencies could determine that less lead-time is maximum
feasible in the final rule. We request comment on these two
alternatives, including the proposed lead-times.
    Table IV-13 and Table IV-14 present a set of assumed adoption rates
for aerodynamic, tire, and ATI technologies that a manufacturer could
apply to meet the proposed standards. These adoption rates begin with
60 percent of long box trailers achieving current SmartWay level
aerodynamics (Bin IV) and progress to 90 percent achieving SmartWay
Elite (Bin VI) or better over the following nine years. The adoption
rates for short box trailers assume adoption of single aero devices in
MY 2021 and combinations of devices by MY 2027. Although the shorter
lengths of these trailers can restrict the design of aerodynamic
technologies that fully match the SmartWay-like performance levels of
long boxes, we nevertheless expect that trailer and device
manufacturers would continue to innovate skirt, under-body, rear, and
gap-reducing devices and combinations to achieve improved aerodynamic
performance on these shorter trailers. The assumed adoption rates for
aerodynamic technologies for both long and short refrigerated vans are
slightly less than for dry vans, reflecting the more limited number of
aerodynamic options due to the presence of their TRUs.
    The gradual increase in assumed adoption of aerodynamic
technologies

throughout the phase-in to the MY 2027 standards recognizes that even
though many of the technologies are available today and technologically
feasible throughout the phase-period, their adoption on the scale of
the proposed program would likely take time. The adoption rates we are
assuming in the interim years--and the standards that we developed from
these rates--represent steady and yet reasonable improvement in average
aerodynamic performance.
    The agencies project that nearly all box trailers will adopt tire
technologies to comply with the standards and the agencies projected
consistent adoption rates across all lengths of dry and refrigerated
vans, with more advanced (Level 2) low-rolling resistance tires assumed
to replace Level 1 tire models in the 2024 time frame, as Level 2-type
tires become more available and fleet experience with these tires
develops. As mentioned previously, the agencies did not include weight
reduction in their technology adoption projections, but certain types
of weight reduction could be used as a compliance pathway, as discussed
in Section IV.D.1.d above.
    The adoption rates shown in these tables are one set of many
possible combinations that box trailer manufacturers could apply to
achieve the same average stringency. If a manufacturer chose these
adoption rates, a variety of technology options exist within the
aerodynamic bins, and several models of LRR tires exist for the levels
shown. Alternatively, technologies from other aero bins and tire levels
could be used to comply. It should be noted that manufacturers are not
limited to aerodynamic and tire technologies, since these are
performance-based standards, and manufacturers would not be constrained
to adopt any particular way to demonstrate compliance. Certain types of
weight reduction, for example, may be used as a compliance pathway, as
discussed in Section IV.D.1.d above.
    Similar to our analyses of the reference cases, the agencies
derived a single set of performance parameters for each subcategory by
weighting the performance levels included in Table IV-8 by the
corresponding adoption rates. These performance parameters represent an
average compliant vehicle for each trailer subcategory and we present
these values in the tables. The 2024 MY adoption rates would continue
to apply for the partial-aero box trailers in 2027 and later model
years.

                             Table IV-13--Projected Adoption Rates and Average Performance Parameters for Long Box Trailers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           Technology                                          Long box dry vans                      Long box refrigerated vans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           Model year                                2018       2021       2024       2027       2018       2021       2024       2027
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies:
    Bin I.......................................................         5%  .........  .........  .........         5%  .........  .........  .........
    Bin II......................................................  .........  .........  .........  .........  .........  .........  .........  .........
    Bin III.....................................................        30%         5%  .........  .........        30%         5%  .........  .........
    Bin IV......................................................        60%        55%        25%  .........        60%        55%        25%  .........
    Bin V.......................................................         5%        10%        10%        10%         5%        10%        10%        20%
    Bin VI......................................................  .........        30%        65%        50%  .........        30%        65%        60%
    Bin VII.....................................................  .........  .........  .........        40%  .........  .........  .........        20%
    Bin VIII....................................................  .........  .........  .........  .........  .........  .........  .........  .........
        Average Delta CDA (m\2\) \a\............................        0.4        0.7        0.8        1.1        0.4        0.7        0.8        1.0
Trailer Tire Rolling Resistance:
    Baseline tires..............................................        15%         5%         5%         5%        15%         5%         5%         5%
    Level 1 tires...............................................        85%        95%  .........  .........        85%        95%  .........  .........
    Level 2 tires...............................................  .........  .........        95%        95%  .........  .........        95%        95%
        Average CRR (kg/ton) \a\................................        5.2        5.1        4.8        4.8        5.2        5.1        4.8        4.8
Tire Inflation System:
    ATI.........................................................         85         95         95         95         85         95         95         95
        Average ATI Reduction (%) \a\...........................       1.3%       1.4%       1.4%       1.4%       1.3%       1.4%       1.4%       1.4%
Weight Reduction (lbs):
    Weight \b\..................................................  .........  .........  .........  .........  .........  .........  .........  .........
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
\a\ Combines projected adoption rates with performance levels shown in Table IV-8.
\b\ This set of proposed adoption rates did not apply any assumed weight reduction to meet the proposed standards for these trailers.

                             Table IV-14--Projected Adoption Rates and Average Performance Parameters for Short Box Trailers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           Technology                                         Short box dry vans                      Short box refrigerated vans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           Model year                                2018       2021       2024       2027       2018       2021       2024       2027
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies: \a\
    Bin I.......................................................       100%         5%  .........  .........       100%         5%  .........  .........
    Bin II......................................................  .........        95%        70%        30%  .........        95%        70%        55%
    Bin III.....................................................  .........  .........        30%        60%  .........  .........        30%        40%
    Bin IV......................................................  .........  .........  .........        10%  .........  .........  .........         5%
    Bin V.......................................................  .........  .........  .........  .........  .........  .........  .........  .........
    Bin VI......................................................  .........  .........  .........  .........  .........  .........  .........  .........
    Bin VII.....................................................  .........  .........  .........  .........  .........  .........  .........  .........
    Bin VIII....................................................  .........  .........  .........  .........  .........  .........  .........  .........
        Average Delta CDA (m\2\) \b\............................        0.4        0.7        0.8        1.1        0.4        0.7        0.8        1.0
Trailer Tire Rolling Resistance:
    Baseline tires..............................................        15%         5%         5%         5%        15%         5%         5%         5%
    Level 1 tires...............................................        85%        95%  .........  .........        85%        95%  .........  .........
    Level 2 tires...............................................  .........  .........        95%        95%  .........  .........        95%        95%
        Average CRR (kg/ton) \b\................................        5.2        5.1        4.8        4.8        5.2        5.1        4.8        4.8

Tire Inflation System:
ATI.............................................................        85%        95%        95%        95%        85%        95%        95%        95%
        Average ATI Reduction (%) \c\...........................       1.3%       1.4%       1.4%       1.4%       1.3%       1.4%       1.4%       1.4%
Weight Reduction (lbs):
    Weight \b\..................................................  .........  .........  .........  .........  .........  .........  .........  .........
--------------------------------------------------------------------------------------------------------------------------------------------------------
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 projected adoption rates with performance levels shown in Table IV-8.
\c\ This set of proposed adoption rates did not apply any assumed weight reduction to meet the proposed standards for these trailers.

    Non-aero box trailers, with two or more work-related special
components, and non-box trailers are not shown in the tables above. We
are proposing that manufacturers of these trailers meet design-based
(i.e., technology-based) standards, instead of performance-based
standards that would apply to other trailers. That is, manufacturers of
these trailers would not need to use aerodynamic technologies, but they
would need to use appropriate lower rolling resistance tires and ATI
systems, based on our assessments of the typical CO2 and
fuel consumption performance of this equipment (see Section IV.2.c).
Thus, we are projecting 100 percent adoption rates of these
technologies at each stage of the program. Compared to manufacturers
that needed aerodynamic technologies to comply, the approach for non-
aero box trailers and non-box trailers would result in a significantly
lower compliance burden for manufacturers by reducing the amount of
tracking and eliminating the need to calculate a compliance value (see
Section IV. F.). The agencies are proposing these design standards in
two stages. In 2018, the proposed standards would require manufacturers
to use tires meeting a rolling resistance of Level 1 or better and to
install ATI systems on all non-box and non-aero box trailers. In 2024,
the proposed standards would require manufacturers to use LRR tires at
a Level 2 or better, and to still install ATI systems. We seek comment
on all aspects of this design-based standards concept. We also seek
comment on providing manufacturers with the option of adopting Level 2
tires in the early years of the program (MY 2018-2023) and avoiding the
use of ATI systems if they chose.

 Table IV-15--Projected Adoption Rates and Average Performance Parameters for Non-Aero Box and Non-Box Trailers
----------------------------------------------------------------------------------------------------------------
                   Technology                                     Non-aero box & non-box trailers
----------------------------------------------------------------------------------------------------------------
                   Model year                          2018            2021            2024            2027
----------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies:
    Bin I.......................................            100%            100%            100%            100%
    Bin II......................................  ..............  ..............  ..............  ..............
    Bin III.....................................  ..............  ..............  ..............  ..............
    Bin IV......................................  ..............  ..............  ..............  ..............
    Bin V.......................................  ..............  ..............  ..............  ..............
    Bin VI......................................  ..............  ..............  ..............  ..............
    Bin VII.....................................  ..............  ..............  ..............  ..............
    Bin VIII....................................  ..............  ..............  ..............  ..............
        Average Delta CDA (m\2\) \a\............             0.0             0.0             0.0             0.0
Trailer Tire Rolling Resistance:
    Baseline tires..............................  ..............  ..............  ..............  ..............
    Level 1 tires...............................            100%            100%  ..............  ..............
    Level 2 tires...............................  ..............  ..............            100%            100%
        Average CRR (kg/ton) \a\................             5.1             5.1             4.7             4.7
Tire Inflation System:
    ATI.........................................            100%            100%            100%            100%
        Average ATI Reduction (%) \a\...........            1.5%            1.5%            1.5%            1.5%
Weight Reduction (lbs):
    Weight \b\..................................  ..............  ..............  ..............  ..............
----------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
\a\ Combines projected adoption rates with performance levels shown in Table IV-8.
\b\ This set of adoption rates did not apply weight reduction to meet the proposed standards for these trailers.

    We request comment and any data related to our projections of
technology adoption rates. The following section (d) explains how the
agencies combined these adoption rates with the performance values
shown previously to calculate the proposed standards.
(e) Derivation of the Proposed Standards
    The average performance parameters from Table IV-14, and Table IV-
15 were applied as input values to the GEM vehicle simulation to derive
the

proposed HD Phase 2 fuel consumption and CO2 emissions
standards for each subcategory of trailers. The proposed standards are
shown in Table IV-16. The proposed standards for partial-aero trailers,
which are not explicitly shown in Table IV-16, would be the same as
their full-aero counterparts through MY 2026. In MY 2027 and later,
partial aero trailers would continue to meet the MY 2024 standards.
    Over the four stages of the proposed rule, box trailers longer than
50 feet would, on average, reduce their CO2 emissions and
fuel consumption by two percent, four percent, seven percent and eight
percent compared to their reference cases. Box trailers 50-feet and
shorter would achieve reductions of two percent, three percent and four
percent compared to their reference cases. The tire technologies used
on non-box and non-aero box trailers would provide reductions of two
percent in the first two stages and achieve three percent by 2027.

                                Table IV-16--Proposed Standards for Box Trailers
----------------------------------------------------------------------------------------------------------------
                                   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                  81             142              82             146
                                 (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard            7.9568         13.9489          8.0550         14.3418
                                 (Gallons per
                                 1,000 Ton-Mile).
2024--2026....................  EPA Standard                  79             141              81             144
                                 (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard            7.7603         13.8507          7.9568         14.1454
                                 (Gallons per
                                 1,000 Ton-Mile).
2027 +........................  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).
----------------------------------------------------------------------------------------------------------------

    It should be noted that 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 recommended by the National Renewable Energy Laboratory (NREL)
and have prepared possible alternative trailer vehicle standards based
on these profiles. The agencies request comment on this analysis, which
is available in a memorandum to the docket.\240\
---------------------------------------------------------------------------

    \240\ Memorandum dated May 2015 on Analysis of Possible Tractor,
Trailer, and Vocational Vehicle Standards Based on Alternative Road
Grade Profiles. Docket EPA-HQ-OAR-2014-0827.
---------------------------------------------------------------------------

(f) Technology Costs for the Proposed Standards
    The agencies evaluated the technology costs for 53-foot dry and
refrigerated vans and 28-foot dry vans, which we believe are
representative of the majority of trailers in the 50-foot and longer
and shorter than 50-foot categories, respectively. We identified costs
for each technology package evaluated and projected the costs for each
year of the program. A summary of the technology costs is included in
Table IV-17 through Table IV-20 for MYs 2018 through 2027, 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-13.
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 technology costs for other years
are thereby affected, refer to Chapter 7 of the draft RIA. We welcome
comment on the technology costs, markups, and learning impacts.

                    Table IV-17--Trailer Technology Incremental Costs in the 2018 Model Year
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                   53-foot  dry    refrigerated    28-foot  dry     Non-aero  &
                                                        van             van             van           non-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-18--Trailer Technology Incremental Costs in the 2021 Model Year
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                   53-foot  dry    refrigerated    28-foot  dry     Non-aero  &
                                                        van             van             van           non-box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................            $602            $602            $468              $0
Tires...........................................              65              65              79             175
Tire inflation system...........................             234             234             426             632
                                                 ---------------------------------------------------------------
    Total.......................................             901             901             974             807
----------------------------------------------------------------------------------------------------------------

                    Table IV-19--Trailer Technology Incremental Costs in the 2024 Model Year
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                   53-foot  dry    refrigerated    28-foot  dry     Non-aero  &
                                                        van             van             van           non-box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................            $836            $836            $608              $0
Tires...........................................              61              61              76             160
Tire inflation system...........................             220             220             412             578
                                                 ---------------------------------------------------------------
    Total.......................................           1,116           1,116           1,097             739
----------------------------------------------------------------------------------------------------------------

                    Table IV-20--Trailer Technology Incremental Costs in the 2027 Model Year
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                   53-foot  dry    refrigerated    28-foot  dry     Non-aero  &
                                                        van             van             van           non-box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................          $1,163          $1,034            $788              $0
Tires...........................................              54              54              74             155
Tire inflation system...........................             192             192             391             549
                                                 ---------------------------------------------------------------
    Total.......................................           1,409           1,280           1,253             704
----------------------------------------------------------------------------------------------------------------

(4) Consistency of the Proposed Trailer Standards With the Agencies'
Legal Authority
    The agencies' initial determination, subject to consideration of
public comment, is that the standards presented in the Section IV.C.2,
are the maximum feasible and appropriate under the agencies' respective
authorities, considering lead time, cost, and other factors. The
agencies' proposed decisions on the stringency and timing of the
proposed standards focused on available technology and the consequent
emission reductions and fuel efficiency improvements associated with
use of the technology, while taking into account the circumstances of
the trailer manufacturing sector. Trailer manufacturers would be
subject to first-time emission control and fuel consumption regulation
under the proposed standards. These manufacturers are in many cases
small businesses, with limited resources to master the mechanics of
regulatory compliance. Thus, the agencies' proposal seeks to provide a
reasonable time for trailer manufacturers to become familiar with the
requirements and the proposed new compliance regime, given the unique
circumstances of the industry and the compliance flexibilities and
optional compliance mechanisms specially adapted for this industry
segment that we are proposing.
    The stringency of the standard is predicated on more widespread
deployment of aerodynamic and tire technologies that are already in
commercial use. The availability, feasibility, and level of
effectiveness of these technologies are well-documented. Thus the
agencies do not believe that there is any issue of technological
feasibility of the proposed standards. Among the issues reflected in
the agencies' proposal are considerations of cost and sufficiency of
lead-time--including lead-time not only to deploy technological
improvements, but also this industry sector to assimilate for the first
time the compliance mechanisms of the proposed rule.
    The highest cost shown in Table IV-20 is associated with the long
dry vans. We project that the average cost per trailer to meet the
proposed MY 2027 standards for these trailers would be about $1,400,
which is less than 10 percent of the cost of a new dry van trailer
(estimated to be about $20,000). Other trailer types have lower
projected technology costs, and many have higher purchase prices. As a
result, we project that the per-trailer costs for all trailers covered
in this regulation will be less than 10 percent of the cost of a new
trailer. This trend is consistent with the expected average control
costs for Phase 2 tractors, which are also less than 10 percent of
typical tractor costs (see Section III).
    The agencies believe these technologies can be adopted at the rates
the standards are predicated on within the proposed lead-time, as
discussed above in Section IV.C.(3). Moreover, we project that most
owners would rapidly recover the initial cost of these technologies due
to the associated fuel savings, usually in less than two years, as
shown in the payback analysis in Section IX. This payback period is
generally considered reasonable in the

trailer industry for investments that reduce fuel consumption.\241\
---------------------------------------------------------------------------

    \241\ Roeth, Mike, et al. ``Barriers to Increased Adoption of
Fuel Efficiency Technologies in Freight Trucking''. July 2013.
International Council for Clean Transportation. Available here:
http://www.theicct.org/sites/default/files/publications/ICCT-NACFE-CSS_Barriers_Report_Final_20130722.pdf.
---------------------------------------------------------------------------

    Overall, as discussed above in IV.D.3.c in the context of our
assumed technology adoption rates, the gradual increase in stringency
of the proposed trailer program over the phase-in period recognizes two
important factors that the agencies carefully considered in developing
this proposed rule. One factor is that assumed adoption of technologies
many of the aerodynamic technologies that box trailer manufacturers
would likely choose are available today and clearly technologically
feasible throughout the phase-period. At the same time, we recognize
that the adoption of these technologies across the industry scale
envisioned by the proposed program would likely take time. The
standards we are proposing in the interim years represent steady
improvement in average aerodynamic performance toward the final MY 2027
standards.

E. Alternative Standards and Feasibility Considered

    As discussed in Section X, the agencies evaluated several different
regulatory alternatives representing different levels of stringency for
the Phase 2 program. The results of the analysis of these proposed
alternatives are discussed below in Section X of the preamble. The
agencies believe each alternative is feasible from a technical
standpoint. However, each successive alternative increases costs and
complexity of compliance for the manufacturers, which can be a
prohibitive burden on the large number of small businesses in the
industry. Table IV-21 provides a summary of the alternatives considered
in this proposal.

    Table IV-21--Summary of Alternatives Considered for the Proposed
                               Rulemaking
------------------------------------------------------------------------

------------------------------------------------------------------------
Alternative 1........................  No action alternative.
Alternative 2........................  Expand the use of aerodynamic and
                                        tire technologies at SmartWay
                                        levels to all 53-foot box
                                        trailers.
Alternative 3 (Proposed Alternative).  Adoption of advanced aerodynamic
                                        and tire technologies on all box
                                        trailers.
                                       Adoption of tire technologies on
                                        non-box trailers.
Alternative 4........................  Same technology and application
                                        assumptions as Alternative 3
                                        with an accelerated introduction
                                        schedule.
Alternative 5........................  Aggressive adoption of advance
                                        aerodynamic and tire
                                        technologies for all box
                                        trailers.
                                       Adoption of aerodynamic and tire
                                        technologies for some tank,
                                        flatbed, and container chassis
                                        trailers.
                                       Adoption of tire technologies for
                                        the remaining non-box trailers.
------------------------------------------------------------------------

    While we welcome comment on any of these alternatives, we are
specifically requesting comment on Alternative 4 for the trailer
program identified as Alternative 4 above and in Section X. The same
general technology effectiveness values were considered and much of the
feasibility analysis was the same in this alternative and in the
proposed alternative, but Alternative 4 applies the adoption rates of
higher-performing aerodynamic technologies from Alternative 3 at
earlier stages for box trailers. This accelerated alternative achieves
the same final fuel consumption and CO2 reductions as our
proposed alternative three years in advance. The following sections
detail the adoption rates, reductions and costs projected for this
alternative.
(1) Effectiveness, Adoption Rates, and Technology Costs for Alternative
4
    Alternative 4 includes the same trailer subcategories and same
trailer technologies as the proposed alternative. Therefore, the zero-
technology baseline trailers (Table IV-7), reference case trailers
(Table IV-10) and performance levels (Table IV-8) described in Section
IV. D. apply for this analysis as well. The following sections describe
the adoption rates of this accelerated alternative and the associated
benefits and costs.
(a) Projected Technology Adoption Rates for Alternative 4
    The adoption rates and average performance parameters projected by
the agencies for Alternative 4 are shown in Table IV-22 and Table IV-
23. Adoption rates for non-aero box and non-box trailers remain
unchanged from the proposed standards and they are not repeated in this
section. From the tables, it can be seen that the 2018 MY aerodynamic
technology adoption rates and the tire technology adoption rates for
all model years are identical to those presented previously for the
proposed standards. The aerodynamic projections for MY 2021 and MY 2024
in this accelerated alternative are the same as those projected for MY
2024 and MY 2027 of the proposed standards, but are applied three years
earlier. In this alternative, the 2021 MY adoption rates would continue
to apply for the partial-aero box trailers in 2024 and later model
years.

                        Table IV-22--Adoption Rates and Average Performance Parameters for the Long Box Trailers in Alternative 4
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Technology                                        Long box dry vans                          Long box refrigerated vans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Model year                              2018            2021            2024            2018            2021            2024
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies: \a\
    Bin I...............................................              5%  ..............  ..............              5%  ..............  ..............
    Bin II..............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin III.............................................             30%  ..............  ..............             30%  ..............  ..............
    Bin IV..............................................             60%             25%  ..............             60%             25%  ..............
    Bin V...............................................              5%             10%             10%              5%             10%             20%
    Bin VI..............................................  ..............             65%             50%  ..............             65%             60%

    Bin VII.............................................  ..............  ..............             40%  ..............  ..............             20%
    Bin VIII............................................  ..............  ..............  ..............  ..............  ..............  ..............
        Average Delta CDA (m2) a........................             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) a..........................             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 (%)a......................            1.3%            1.4%            1.4%            1.3%            1.4%            1.4%
Weight Reduction (lbs):
    Weight b............................................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
a Combines adoption rates with performance levels shown in Table IV-8.
b This set of adoption rates did not apply weight reduction to meet the proposed standards for these trailers.

                       Table IV-23--Adoption Rates and Average Performance Parameters for the Short Box Trailers in Alternative 4
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Technology                                       Short box dry vans                          Short box refrigerated vans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Model Year                              2018            2021            2024            2018            2021            2024
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies a
    Bin I...............................................            100%  ..............  ..............            100%  ..............  ..............