Summary and Analysis of Comments
Clean Fuel Fleet Program
Emission Standards for Clean Fuel Vehicles,
Requirements for Vehicle Conversions,
and the California Pilot Test Program
June 14, 1994
Special Regulatory Projects Branch
Regulatory Development and Support Division
Office of Mobile Sources
Office of Air and Radiation
U S. Environmental Protection Agency

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TABLE OF CONTENTS
List of Commenters
List of Key Acronyms
Introduction
Discussion of Issues
I. Clean Fuel Fleet Program
Effective Date
n. Clean-Fuel Vehicle Standards
A.	General
1.	Zero-Emission Vehicles
2.	THC, NMHC, and NMOG Standards
B.	Light-Duty
1.	Applicability of CARB Standards
2.	Certification Fuel
C.	Heavy-Duty
1.	Low-Emission Vehicle Standard (NMHC + Nox)
a.	Feasibility of Statutory 3.15 g/Bhp-hr NMHC + Nox Level
b.	Feasibility of Proposed 3.5 g/Bhp-hr NMHC + Nox Standard
2.	Ultra Low-Emission Vehicle (ULEV) standards
3.	Heavy-Duty Dual-Fuel and Bi-Fuel Emission Standards
4.	Averaging, trading, and banking
5.	Credit Exchange Programs for Manufacturers of Heavy-Duty Clean-
Fuel Fleet Vehicles
III. Conversions
A.
Definition of "Manufacturer" Certification, Warranty, and Liability Provisions

for CFV Conversions
B.
Liability of the Original Equipment Manufacturer
C.
Definition of a Converted Vehicle's Useful Life
D.
Post-Installation Quality Test
E.
On-Board Diagnostics
F
Applicability of the Small Volume Manufacturers Certification Program to

Conversions
G.
Vehicle Safety
H.
Purchase Requirements
I
Suggestions for Special Treatment of Conversions for Testing and Certification

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TABLE OF CONTENTS
(continued)
IV. California Pilot Test Program
A.	Clean Fuel Vehicle Standards
B.	Treatment of Small Volume Manufacturers
VI. Regulatory Impacts
A.	Program Costs
B.	Additional Program Impacts

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Clean Fuel Fleet and California Pilot Program
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LIST OF COMMENTERS
American Automobile Manufacturers Association (AAMA)
American Petroleum Institute (API)
American Gas Association (AGA)
Association of International Automobile Manufacturers (ALAM)
Chicago Department of the Environment
Ciba
Cummins Engine Company
Electric Transportation Coalition (ETC)
Engine Manufacturer's Association (EMA)
Federal Express Corporation
General Motors Corporation (GM)
Hackensack Water Company
Illinois Environmental Protection Agency
Mobil Oil Corporation
National Association of Fleet Administrators, Inc (NAFA)
Natural Gas Vehicle Coalition (NGVC)
Pennsylvania Department of Environmental Resources
Pennsylvania Department of Transportation
Rover Group
Sun
Texaco
Virginia, Maryland, and Delaware Association of Electric Cooperatives

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Clean Fuel Fleet and California Pilot Program
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LIST OF KEY ACRONYMS
AT&B:
averaging, trading, and banking
BHP:
brake horsepower
CAA:
Clean Air Act
CARB:
California Air Resources Board
CFF:
clean-fuel fleet
CFFV:
clean-fuel fleet vehicle
CFR:
Code of Federal Regulations
CFV-
clean-fuel vehicle
CO:
carbon monoxide
cpp-
California Pilot Program
CST:
certification short test
EGR:
exhaust gas recirculation
EPA:
Environmental Protection Agency
FEL:
family emission limit
FR:
Federal Register
FRM:
Final Rulemaking
FTP:
Federal Test Procedure
g"
grams
GVWR-
gross vehicle weight rating
h:
hour
HC
hydrocarbon
HCHO
formaldehyde
HD:
heavy-duty
HDD:
heavy-duty diesel
HDDE:
heavy-duty diesel engine
HDE-
heavy-duty engine
HDV:
heavy-duty vehicle
ILEV-
inherently low-emission vehicle
lbs.-
pounds
LDT:
light-duty truck
LEV-
low-emission vehicle
LDV:
light-duty vehicle
LVW
loaded vehicle weight
NGV-
natural gas vehicles
NMHC
non-methane hydrocarbon
NMHCE-
non-methane hydrocarbon equivalent
NMOG
non-methane organic gas
(continued
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Clean Fuel Fleet and California Pilot Program
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LIST OF KEY ACRONYMS
(continued)
NPRM:	Notice of Proposed Rulemaking
NO,:	oxides of nitrogen
OBD:	on-board diagnostics
OEM-	original equipment manufacturer
ORVR:	onboard refueling vapor recovery
PM:	particulate matter
RAF:	reactivity adjustment factor
SIP:	State Implementation Plan
SVM"	small volume manufacturer
TCM-	transportation control measure
THC:	total hydrocarbon
TLEV:	transitional low-emission vehicle
ULEV:	ultra low-emission vehicle
VOC:	volatile organic compound
ZEV:	zero-emission vehicle
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Clean Fuel Fleet and California Pilot Program
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INTRODUCTION
The regulatory changes being finalized today for the Clean Fuel Fleet Program and the
California Pilot Program were proposed on June 10, 1993 (58 FR 32474) and June 29, 1993 (58 FR
34727), respectively. In the Clean Fuel Fleet Program Notice of Proposed Rulemaking (NPRM), EPA
proposed clean-fuel vehicle (CFV) heavy-duty standards and conversion regulations, and in the
California Pilot Program NPRM, EPA proposed CFV emission standards for light-duty vehicles and
light-duty trucks, sales requirements, and state opt-in program requirements. EPA is finalizing these
rules together, and this document addresses the public comments relating to the above parts of the
Clean Fuel Fleet NPRM and the California Pilot Program NPRM.
EPA held a public hearing on these issues on July 15, 1993 at Domino's Farms Conference
Facility in Ann Arbor, Michigan. Comments were accepted at that time and for sixty days thereafter,
until September 15, 1993, as described in the notice of extension of the comment period (58 FR
42266, August 9, 1993). Comments were submitted at the hearing by: Cummins Engine Company,
American Automobile Manufacturers Association, National Association of Fleet Administrators, The
Natural Gas Vehicle Coalition and American Gas Association, GE Capital Fleet Services, Engine
Manufacturers Association, and the State of Wisconsin. Written comments after the hearing were also
submitted by these commenters and the additional commenters listed above.
Interested persons are referred to the public docket for this rulemaking for the transcript of the
hearing and copies of all written comments.
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Clean Fuel Fleet and California Pilot Proeram
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DISCUSSION OF ISSUES
The following is the summary and analysis of comments received concerning this rulemaking.
It is organized by issue area within each major subject of regulation.
I.	Clean Fuel Fleet Program
Effective Date
Summary of Issue and Comments
Sun stated that the federal clean fuel fleet emission standards should be consistent with the
California Pilot Program and require clean-fuel fleet vehicles to meet Phase I standards from model
year 1998 through 2000, and Phase II standards in model year 2001.
Analysis and Response to Comments
Section 243 of the Clean Air Act specifies the exhaust emission standards for the Clean Fuel
Fleet Program and the California Pilot Program. These standards are prescribed in two phases for
light-duty vehicles and light-duty trucks (up to 5,750 lbs. LVW and 6,000 lbs. GVWR). Under section
243, Phase I standards apply to clean-fuel vehicles in model years 1996 through 2000, while Phase II
standards apply to such vehicles in model year 2001 and later. However, section 246(c) of the Act
requires CFVs in the Clean Fuel Fleet Program to meet the Phase II CFV standards, regardless of the
model year in which the fleet program purchase requirements are effective. Therefore, Phase I
standards apply only to the California Pilot Program and are effective from 1996 through the 2001
model year. The Phase II standards apply to the Clean Fuel Fleet Program in model year 1998 and to
the California Pilot Program in model year 2001. Since EPA has no discretion to change the effective
dates of the standards, EPA is adopting the proposed effective dates for Phase I and Phase II
standards.
II.	Clean-Fuel Vehicle Standards
A. General
1. Zero-Emission Vehicle
Summary of Issue
In the proposal, EPA defined a ZEV as a motor vehicle which, through engineering analysis
meets the following conditions
1) All primary and auxiliary equipment and engines must have no emissions of NMOG, CO.
NO,, PM and HCHO,
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Clean Fuel Fleet and California Pilot Program
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2)	The vehicle fuel systera(s) must not contain either carbon or nitrogen compounds (including
air) that, when burned, form the above regulated exhaust emissions, and
3)	The vehicle fuel system(s) and any auxiliary engme(s) must have no evaporative emissions.
In addition, EPA proposed that any vehicle with additional power system(s) or auxiliary engine(s) that
might produce regulated pollutants (e.g., hybrid vehicle or an electric vehicle with an auxiliary power
source to run other vehicle systems) will be subject to the testing requirements of 40 CFR 86 or 88 or
future applicable regulations and may not qualify as a ZEV. EPA requested comment on whether the
ZEV vehicle heater previsions adopted by CARB should be mcluded in this rulemaking. For ZEVs
equipped with auxiliary heaters, the auxiliary heaier could not be operated at ambient temperatures
above 40 degrees Fahrenheit.
Summary of Comments
The Natural Gas Vehicle Coalition and the American Gas Association (NGVC-AGA)
recommended that EPA modify the proposed ZEV definition to allow vehicles with minimal exhaust
and inherently low evaporative emissions to qualify. They also suggested exhaust emission standards
for light-duty and heavy-duty ZEVs based on an analysis of the emission levels achievable by hybrid-
electnc and gas-turbine electric vehicles. The Natural Gas Vehicle Coalition suggested that EPA allow
a manufacturer to certify a vehicle as a ZEV by demonstrating that the vehicle meets these emission
standards. They did not support the proposed ZEV definition because the zero exhaust and
evaporative emission requirement limits the qualifying technology to battery-electric propulsion
systems. They stated that, because of the many negative aspects associated with this technology, there
are other electric technologies that, although having minimal exhaust and evaporative emissions,
overall may be a more practical alternative.
The Electric Transportation Coalition (ETC) commented that EPA should allow the
certification of ZEVs with auxiliary heaters. The California LEV program includes this allowance.
They pomted out that CAA section 249(d)(3) requires that standards for issuing credits for cleaner
vehicles under the Clean Fuel Fleet Program shall also apply for purposes of the Pilot program. Given
the acknowledged overlap between the Pilot program and the California LEV program, ETC argued
that credit standards for light- and heavy-duty ZEVs should provide for the certification of ZEVs with
auxiliary heaters.
ETC also commented that adoption of the CARB approach on the certification of 2LEVs with
auxiliary heaters is necessary to comply with the section 246(f)(4) CAA requirement that ZEV and
ULEV emission standards for purposes of issuing credits in the CFFV program are required to
"conform as closely as possible to standards which arc established by the State of California for ULEV
and ZEV vehicles in the same class". This same section requires the Administrator to promulgate
"comparable" ZEV emission standards for vehicles with a gross vehicle weight rating (GVWR) of
8,500 pounds or more. According to ETC. to assure mmparability with light-duty vehicle standards,
heavy-duty vehicles equipped with auxiliary heateis ih.il iiieel CARB limitations should be entitled to
certification as ZEVs. ETC stated that CARB provisions are designed to enable ZEVs to be equipped
to meet customer requirements in climatic regions where heating capability is required ETC believes
that these provisions allow vehicle designers and manulauurers technological flexibility to meet

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Clean Fuel Fleet and California Pilot Program
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market needs. They also provide compliance flexibility. ETC commented that it is consistent with the
purpose of the ZEV standards as well as the CFF credit program to provide additional encouragement
for the use of vehicles capable of the greatest emission reductions, to permit auxiliary heater-equipped
vehicles to be certified as ZEVs.
Finally, the ETC provided a list of state incentives that could be used to spur the introduction
of ZEVs. This list included ideas for various tax incentives, exemptions for electric vehicle from
various taxes and restrictions currently imposed on conventional vehicles, subsidies, state commercial
support programs, and supportive tax policies for development of electric vehicle industries and
infrastructure.
Analysis of Comments
The comments support allowing electric vehicles with auxiliary heaters that do not operate
above 40 degrees Fahrenheit to certify as ZEVs. EPA believes there is merit in this since it would
increase the consistency between the federal clean-fuel vehicle programs and the California LEV
Program and would only add to the marketability of ZEVs. In addition, section 246(f)(4) requires
EPA to establish ZEV and ULEV standards that "conform as closely as possible" to CARB's ZEV and
ULEV standards for vehicles in the same class. This provision of the Act supports adopting a
definition of "zero-emission vehicle" that is consistent with CARB's definition, although it does not
require EPA to adopt a definition that is identical to CARB's.
As mentioned in the preamble to this final rule, EPA has not established emission standards
for ZEVs because, at this point in time, a test procedure has not been developed. In addition, CARB
has not established ZEV evaporative emission standards or minimal exhaust emission standards to
date, nor have they modified their definition of a ZEV to allow other technologies to qualify. While
there may be some merit to the argument that vehicles with inherently low or minimal evaporative
emissions could have an overall emissions impact similar to ZEVs (if power plant emissions were
included), the EPA vehicle emission control program at present deals only with vehicle-related
emissions. Thus, vehicles with minimal emissions would likely be certified as LEVs or ULEVs.
EPA does not believe it is appropriate to allow manufacturers to certify vehicles as ZEVs by
demonstrating that the vehicles meet certain specified exhaust and evaporative emissions standards.
Aside from credits and the specific exemptions required by CAA section 246(h) for clean-fuel
fleet vehicles, the CAA does not authorize the Agency to establish additional incentives for electric
vehicles, such as those suggested by the ETC. Rather, according to CAA section 249(f)(3), states
which voluntarily opt into the California Pilot Program may offer mcentives to encourage the sale and
use of CFVs.
Response to Comments
EPA is allowing a ZEV to be equipped with an auxiliary heater provided that the heater camvi
be operated at ambient temperatures above 40 degrees Fahrenheit. This is consistent with the
provisions in the California LEV Program.
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Clean Fuel Fleet and California Pilot Program
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For the reasons discussed above, EPA is at this time modifying the ZEV definition to allow
vehicles with minimal exhaust and inherently low evaporative emissions to qualify. For purposes of
this rulemaking, ZEVs will be defined as having zero exhaust emissions of the above regulated
pollutants and zero evaporative emissions.
2. THC, NMHC, and NMOG Standards
a. THC Standard
Summary of Issue
The CAA establishes both total hydrocarbon (THC) and non-methane hydrocarbon (NMHC)
exhaust emission standards for conventional light-duty gasoline and diesel vehicles. CAA section 242
requires clean-fuel vehicles to meet these standards except where such a requirement is in conflict with
Part C of the CAA. EPA proposed that natural gas clean-fuel vehicles be exempt from compliance
with the federal THC emission standard because such vehicles would likely not be able to meet this
standard due to their high methane exhaust emissions. EPA expressed in the NPRM that subjecting
natural gas clean-fuel vehicles to the THC standard would be in conflict with the fuel-neutral intent of
the clean-fuel vehicle programs since it would likely exclude CNG vehicles from the program. Yet,
EPA concluded at that time that such an exemption would not conflict with the objecuves of the CFV
programs to reduce emissions of ozone-forming pollutants.
Summary of Comments
The Natural Gas Vehicle Coalition strongly supported not subjecting natural gas clean-fuel
vehicles to the federal THC standard now or in the future. They believed subjecting their vehicles to
this requirement would preclude them from the marketplace.
Analysis and Response to Comments
EPA agrees with NGVC's comments on this issue, and, as proposed, is exempting light-duty
natural gas clean-fuel vehicles (i.e., up to 8,500 lbs GVWR) from compliance with the federal THC
standard. EPA believes that to subject such vehicles (o the federal THC standard would conflict with
Part C of Title II of the CAA. EPA believes that Congress intended the clean-fuel vehicle programs
to be fuel-neutral. A clean-fuel vehicle may use any fuel, as long as it meets the clean-fuel vehicle
standards when it operates on that fuel. EPA believes that vehicles that operate on natural gas would
be precluded from participation in the federal clean-fuel vehicle program if such vehicles were
required to meet the federal THC standard. In addition, the Gaseous Fuels rule contains such an
exemption for natural gas vehicles, and it is EPA's intent in this rulemaking to establish requiremenis
for clean-fuel vehicles that are as consistent as possible with the requirements of the Gaseous Fuels
rule. There were no comments that supported a THC standard for natural gas clean-fuel vehicles II
in the future THC requirements are applied to CNG \ehicles in general. EPA believes that such a
requirement should also be applied to CNG CFVs
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Clean Fuel Fleet and California Pilot Program
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b.	Measurement of NMHC from Natural Gas Vehicles (NGVs)
Summary of Issue and Comments
NGVC-AGA (Natural Gas Vehicle Coalition and American Gas Association) commented on
the measurement of NMHC, which is needed to measure compliance with the HD CFV combined
NMHC + Nox standard, for NGVs. In the proposal, EPA proposed that NMHC be determined by
subtracting measured methane (multiplied by an adjustment factor) from measured THC. NGVC-AGA
believes the proposed method of determining NMHC is inappropriate. They stated that experience has
shown that the magnitude of the uncertainty in NGV NMHC emissions determined by this approach
frequently exceeds the magnitude of the true NMHC value. Furthermore, NGVC-AGA believes such
large errors are unacceptable for certification standards as stringent as CFV standards. Thus, NGVC-
AGA urged EPA to adopt the CARB method of direct measurement of NMHC by gas
chromatography.
Analysis and Response to Comments
EPA has addressed similar concerns related to the measurement of NMHC emissions for
NGVs in the Gaseous Fuels final rulemaking (promulgated on May 27, 1994). In the Gaseous Fuels
rule, the NMHC test procedure has been modified from the original test procedure established by the
Tier 1 rulemaking (56 FR 25724, June 5, 1991) for conventional vehicles. These modifications have
been made to account for the inaccuracy of the FID response to high levels of exhaust methane
produced from natural gas vehicles. EPA considered an NMHC test procedure using gas
chromatography for the Gaseous Fuels rule. However, this test is time-consuming and is not currently
practical for most non-laboratory vehicle testing. Currently, EPA is involved with a cooperative
research and development project that is looking into measuring NMHC from a vehicle/engine using a
direct NMHC analyzer, however, this equipment is not yet ready for commercial use.
The Gaseous Fuels FRM establishes the standards and test procedures for NGVs in general.
EPA is not modifying these procedures for natural gas clean-fuel vehicles since there is currently no
practical alternative test procedure for such vehicles. Instead, EPA is promulgating a NMHC
measurement method for this rule that is the same as the method established in the Gaseous Fuels
FRM. If the NMHC measurement procedure for all NGVs is revisited and changed in the future, then
EPA believes any revised method should apply to clean-fuel vehicle testing as well. Further
information can be found in the docket supporting the Gaseous Fuels final rule.
c.	NMOG vs. NMHC
Summary of Issue and Comments
One commenter, NGVC-AGA. recommended ih.it EPA — in applying the heavy-duty 3.15
g/BHP-hr standard to gaseous and alcohol fueled engines -- base the standard on Nox plus reactivity-
adjusted NMOG, rather than Nox plus adjusted NMHC (NMHCE) alone. They believe this would
more accurately account for the real ozone unpads of these clean fuels, and would be consistent with
the intent of Congress in adopting the CFF program Furthermore, they also believe this intent was
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
expressed in the requirement that EPA adopt reactivity evaluation criteria consistent with California's.
NGVC-AGA also commented that although the CAA does not specifically authorize the use of NMOG
instead of NMHC for HD CFV engines, it also does not specifically authorize the use of NMHCE.
They also stated that since it would be unreasonable to assume that Congress intended not to regulate
aldehyde and alcohol emissions for HD CFVs, EPA would be within its authority to adopt an
appropriate VOC measure for these vehicles - either NMHCE or NMOG. Moreover, NGVC-AGA
commented that of these two, reactivity-adjusted NMOG is by far more scientifically defensible
method of measurement, and this measurement was also adopted by Congress in setting emissions
standards for light-duty CFVs, which indicates that the use of this measurement is consistent with
Congressional intent.
Analysis and Response to Comments
Congress applied CARB's NMOG standards for LDVs and LDTs to LDV and LDT CFVs, and
yet specifically applied NMHC standards to HD CFVs. NMHC standards are traditionally applied to
conventional petroleum fueled vehicles, and Congress seems to have expected that conventional
vehicles would play a major role in heavy-duty portion of the fleet program. This is reinforced by the
fact that Congress provided in section 245(b) that if HD CFV standards are not technologically
feasible for diesels, EPA may set a less stringent standard. Because of these provisions, EPA believes
that is not appropriate to use an NMOG standard for HD CFVs and will use NMHC for the HD CFV
standards, as proposed. It is also worth noting that EPA's use of an NMHC standard is consistent
with CARB's incomplete medium-duty vehicle and diesel engine standards.
4. Dual- and Flexible-fuel Vehicle Requirements
Summary Issue and Comments
One commenter, Illinois EPA, requested that EPA clarify whether the definitions of "dual-fuel
vehicle" and "flexible-fuel vehicle" are intended to apply to vehicles converted to CFVs as well as to
OEM vehicles. They believe it is necessary to clearly state whether converted vehicles are mcluded in
these definitions and, if so, what restrictions may apply.
In addition, Illinois EPA commented that the definition of ILEV states that no dual-fuel
vehicle or flexible-fuel vehicle shall be considered an ILEV unless it is certified to the applicable
standards on all fuel types on which it is designed to operate. Thus, Illinois EPA also asked whether a
similar certification restriction for dual- and flexible-fueled vehicles should be mcluded in the
definitions for LEV and ULEV.
Analysis and Response to Comments
Elsewhere in this document. EPA is adopting the proposed approach for CFV conversion
configurations that requires that they be treated as OEM CFVs in all essential respects, this includes
the treatment of vehicles converted to dual- and flexible-fuel CFVs Therefore, the definitions of
"dual-fuel vehicle" and "flexible-fuel vehicle" apply to vehicles converted to CFVs as well as to OEM
CFVs.
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Clean Fuel Fleet and California Pilot Program
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As to applying the ELEV approach to dual-/flexible-fuel CFVs in general, EPA believes that
this would not be appropriate. Section 243(d) of the Act requires EPA to establish two levels of
specific exhaust standards for light-duty dual-/flexible fuel CFVs. EPA does not believe it has the
authority to use a different approach, and is adopting the statutory dual-/flexible-fuel CFV standards
for all light-duty CFVs (conversions and OEMs).
B. Light-Duty
1. Applicability of CARB Standards
Summary of Issue
Clean Air Act section 243 provides that CARB emission standards can, in certain
circumstances, replace the federal clean-fuel vehicle standards. Section 243(e) states that if CARB's
standards are, in the aggregate, at least as protective of public health and welfare as the CAA
standards in sections 242 and 243, and the CARB standards have received a waiver under section
209(b), then CARB's standards will apply to clean-fuel vehicles in lieu of the standards otherwise
applicable under sections 242 and 243.
EPA proposed that federal emission standards apply to clean-fuel vehicles covered under the
Clean Fuel Fleet and Pilot programs. This means that the federal exhaust standards, plus federal
requirements for cold temperature carbon monoxide, evaporative emissions, refueling emissions, non-
methane hydrocarbon emissions, and, with certain exceptions, total hydrocarbon emissions would
apply. EPA also proposed that, if CARB finalized the California LEV Program, and the CARB
requirements were, in the aggregate, at least as protective of public health and welfare as the federal
clean-fuel vehicle standards, then EPA would, in the final rule, adopt the California standards under
CAA section 243(e)(2).
Summary of Comments
Citing the authority of CAA section 243, commenters were strongly in favor of replacing the
federal standards with those of CARB. Both the American Automobile Manufacturers Association
(AAMA) and the Association of International Automobile Manufacturers (ALAM) commented that
CARB procedures and standards should be adopted in their entirety under CAA section 243. They
noted that EPA has already stated that the TLEV and LEV tailpipe standards adopted by CARB are
identical to those in the Pilot program. They also mentioned that CARB's evaporative emissions
procedures are highly similar to those established by EPA and believe the programs will be virtually
the same for 1996 and later model years. They noted that EPA is allowing California OBDII to be
sold in lieu of federal systems through the 1998 model \ear, although the two programs vary
somewhat. In addition, AAMA pointed out that EPA granted a waiver for the California LEV
program under Section 209(b), and that the LEV program waiver was required to be based on the
relative stringency of California's motor vehicle regulations "in the aggregate", rather than on an
evaluation of a given standard "in isolation" AAM \ noted that, in the NPRM for thrs rulemaking.
EPA proposed to use federal standards for THC and S'MHC because CARB had not yet finalized
reactivity adjustment factors (RAFs) for all alternative luels
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Clean Fuel Fleet and California Pilot Program
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However, AAMA also noted that, in the California LEV waiver, EPA stated that, although
CARB had not finalized RAFs for all alternative fuels, the "CARB regulations do include, however,
the procedure and protocols a manufacturer can follow to formulate a RAF for any alternative fuel
which has not yet been assigned a RAF by CARB procedure and submitting it to the CARB Executive
Director for approval" On this basis, EPA granted the LEV waiver despite the absence of finalized
RAFs. AAMA believes that EPA should similarly determine that each set of California low-emission
vehicle standards is, in the aggregate, at least as protective of public health and welfare as the
applicable federal standards m Sections 242 and 243, despite the absence of finalized RAFs.
The Illinois Environmental Protection Agency supported considering any vehicle that has been
certified to California LEV standards as meeting the federal clean-fuel vehicle standards. They
commented that vehicles in the Clean Fuel Fleet and Pilot programs should be required to be certified
to California standards and procedures because 1) California's LEV standards and the clean-fuel
vehicle exhaust emission standards in section 243 of the CAA are identical, and 2) EPA proposed that
"any vehicle certified in California to the same standards as the clean-fuel vehicle exhaust emission
standards be considered to satisfy the requirements for certification to the equivalent federal clean-fuel
vehicle exhaust emission standards". The Illinois EPA believes a state should be able to accept a
California certification as well as a federal certification, to show compliance with the clean-fuel fleet
vehicle standards.
Analysis and Response to Comments
EPA disagrees with commenters who stated that a present-day comparison of federal CFV
standards and CARB standards demonstrates that the CARB LEV program requirements are at least as
stringent as the federal requirements that apply to clean fuel vehicles. The fact that the CFV standards
in section 243 are identical to CARB's exhaust emission standards for low-emission vehicles does not,
as many commenters suggested, mean that the CARB standards should automatically replace the
standards in section 243. The determination that EPA made pursuant to section 209(b) to waive
federal preemption for CARB's low emission vehicle standards is not the same as the determination
that EPA must make to replace the federal CFV standards under section 243(e). Under Section
209(b), EPA must compare the California motor vehicle pollution control program in its entirety to the
federal motor vehicle pollution control program. Under section 243(e)(2), EPA must compare each set
of California standards adopted pursuant to a waiver of federal preemption to the federal CFV
standards in section 243 (exhaust emission standards) and 242 (other requirements of Title II such as
Cold CO, evaporative emission, onboard refueling vapor recovery, on-board diagnostics, total
hydrocarbons, and non-methane hydrocarbon standards)
The fact that the determination EPA must make under Section 243(e)(2) must be made using
California's standards for which EPA has already waived federal preemption indicates that this
determination is different from the determination EPA makes under section 209(b). Further, even
though EPA has waived federal preemption for most ol the existing California LEV program,
California standards will not apply to federal CFVs unless the California standards also meet the
section 243(e) criteria. If EPA's waiver of federal preemption for California's LEV program
automatically required the replacement of federal CFV standards with CARB standards. Section 24?k '
would not be necessary. EPA believes that such a ie.Kling of the statute renders section 243(e)
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
superfluous. Therefore, EPA is interpreting Section 243(e)(2) as proposed, and for the reasons
discussed below cannot at this ume replace the CFV standards and requirements with CARB LEV
standards and requirements.
As stated above, in defining the California program for purposes of comparison under section
243(e) several components of the finalized California program which have not yet received waiver of
federal preemption cannot properly be included as part of the current California program. Such
components of which the Agency is aware include California's Cold CO standards, evaporative
emission standards, and on-board diagnostics. With regard to any potential onboard refueling vapor
recovery regulations, CARB has not yet made a decision as to how to respond to the federal ORVR
requirements, let alone received a waiver for any such regulation. In the absence of waived Cold CO
standards, revised evaporative emission standards, and revised on-board diagnostics requirements as
well as any on-board vapor recovery regulation, the Agency cannot, at this time, affirmatively
conclude that each set of the California standards applicable to clean-fuel vehicle categories is at least
as protective of the public health and welfare as the existing federal CFV standards and requirements
delineated in sections 242 and 243 of the CAA.
In comments submitted to EPA during this proceeding, the AAMA noted that EPA stated in
the NPRM that because "...CARB has not yet finalized its Reactivity Adjustment Fact [sic] (RAF)
assignments for all alternative fuels, and therefore, in the absence of these RAFs, EPA proposes to use
the federal total hydrocarbon standards and the federal non-methane hydrocarbon standards." The
Agency believes that AAMA has misconstrued the NPRM. EPA has proposed and finalized the
application of federal NMHC and THC standards to CFVs because section 242 requires that Clean
Fuel Vehicles shall comply with "all motor vehicle requirements of this title...." unless EPA replaces
the federal CFV standards with California standards under section 243(e). This is separate from the
fact that the lack of finalized RAFs further complicates an already complicated comparison of NMOG
standards to NMHC or THC standards for compliance purposes.
Generally, with regard to volatile organic compounds from vehicles, EPA and California use
different approaches to regulate such emissions. EPA requires compliance with NMHC standards,
while CARB requires compliance with NMOG standards. In the LEV waiver, EPA found that the
California LEV program resulted in a California program which was as or more protective as the
federal program would have been in California. In the Agency's consideration of California's request
for waiver of federal preemption for California's low emission vehicle program California's
"...determinations that [California's regulations] compli[ied] with the statute, when presented to the
Administrator are presumed to satisfy the waiver requirements." MEMA I. 627 F.2d at 1121. The
burden of convincing the Administrator that the waiver should not be granted is on the opponents of
the waiver. IcL
As stated above, the relative protectiveness assessment EPA must make in the section
243(e)(2) context is different that the one made in the section 209(b) context. Under section
243(e)(2), EPA must assure itself that each set of the CARB standards will be. in the aggregate, at
least as protective of the public health and welfare as the federal CFV standards in sections 242 and
243. The burden of reasonableness is on the EPA
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Clean Fuel Fleet and California Pilot Prosram
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In addition, the Agency has attempted to determine whether compliance with the California
NMOG standards would indicate compliance with the federal NMHC and/or THC standards. This
determination will assist the Agency in evaluating whether it will be necessary for a manufacturer to
provide evidence of compliance with these federal HC standards directly (by measuring or calculating
NMHC or THC levels) or whether a manufacturer may provide only evidence of compliance with the
CARB NMOG standards and the Agency could consider such data as adequate evidence of compliance
with the federal NMHC and THC standards. It is in this evaluation that the absence of RAFs hinders
the Agency's ability to make a reasonable determination regarding the relationship between submission
of NMOG data and existing NMHC and THC standards. Without specific RAFs the Agency is not in
a position to assure itself that NMOG levels indicate compliance with NMHC or THC standards.
EPA's role under section 243(e)(2) is significantly different from the Agency's role in reviewing
California's methodology and policy choices submitted in the context of a section 209 waiver
proceeding.
As described above, EPA cannot adopt CARB standards for the federal clean-fuel vehicle
program in this Final Rule because EPA cannot at this time affirmatively make the finding required by
section 243(e) in order to apply CARB standards. Therefore, as proposed, federal exhaust emission
and other Title II standards will apply to clean-fuel vehicles in both the Clean Fuel Fleet Program and
the California Pilot Program. However, as proposed, because of the emission margin which exists
between the federal clean fuel vehicle exhaust standards and the CARB LEV and ULEV categories of
standards, a vehicle certified to the corresponding California LEV or ULEV categories of exhaust
standards will be deemed to sausfy the corresponding federal clean fuel vehicle standards for
certification purposes. Finally, if EPA later determines that each set of the California standards is, in
the aggregate, at least as protective as the federal standards in sections 242 and 243, then EPA will
inmate a separate rulemaking to replace the federal CFV standards promulgated today with California
standards as required by section 243(e)(2).
2. Certification Fuel
Summary of Issue and Comments
The American Automobile Manufacturers Association commented that California certification
and commercial fuels should be required in both the Clean Fuel Fleet Program and the California Pilot
Program. They also stated that EPA should require any state opting into the Pilot program to adopt
California commercial fuel specifications and credits for such states should only be allowed if these
fuels are part of the program. The Association of International Automobile Manufacturers commented
that conventionally fueled vehicles sold under the Pilot program should be certified on California's
Phase II certification test fuel.
Analysis and Response to Comments
As discussed previously, EPA is applying federal standards, as opposed to California
standards, to all clean-fuel vehicles. Because the federal light-duty clean-fuel vehicle exhaust emission
standards are identical to those of CARB, EPA believes these federal standards must be administered
and enforced per CARB procedures and policies as is specified in CAA section 244. Section 244
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Clean Fuel Fleet and California Pilot Program
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requires EPA to administer and enforce the clean-fuel vehicle exhaust emission standards in the same
manner and with the same flexibility as California administers and enforces the California Low-
Emission Vehicle Program standards, including requirements regarding certification. CARB allows
manufacturers to certify vehicles to the Califonua LEV standards on California reformulated test
gasoline as well as on indoiene Therefore, as required by section 244, certification testing of clean-
fuel vehicles is permitted using either or both of those fuels, as well as usmg any other fuel on which
CARB permits certification testing to be performed. EPA is considering further rulemaking action to
permit clean-fuel vehicle certification on other fuel formulations.
C. Heavy-Duty
1. Low-Emission Vehicle Standard (NMHC + NOx)
Summary of Issue
Section 245 of the CAA sets forth the statutory framework governing establishment of the
heavy-duty clean-fuel vehicle standards. Section 245(a) sets a combined NMHC + Nox standard of
3.15 g/Bhp-hr for engines intended for use m heavy-duty clean-fuel vehicles, reflecting a 50 percent
reduction from the current combmed HC and Nox standards for heavy-duty diesel engmes (HDDE).
However, section 245(b) permits EPA to set a less stringent standard or standards if EPA determines
that the statutory level of 3.15 g/Bhp-hr is infeasible for clean diesel-fueled engines. Under this
provision, EPA must make a determination as to the feasibility of this standard for clean diesel-fueled
engine technology, taking into account "durability, costs, lead time, safety, and other relevant factors."
If the Administrator determines that the standard is not feasible for clean diesel-fueled engines, EPA
may set a less stringent standard so long as it is at least a 30 percent reduction from the combined
NMHC plus Nox standards for model year 1994 heavy-duty engines. A 30 percent reduction would
be equivalent to a NMHC plus Nox standard of 4.41 g/Bhp-hr. In the proposal, EPA proposed that a
combined NMHC + Nox emission standard of 3.15 g/Bhp-hr was infeasible for clean diesel-fueled
engines, and thus, based on feasibility considerations EPA proposed a combined NMHC + Nox
standard of 3.5 g/Bhp-hr.
a. Feasibility of Statutory 3.15 g/Bhp-hr NMHC + NOx Level
Summary of Comments
Following is a summary of comments on the heavy-duty CFV LEV standard. In response to
the NPRM, EPA received conflicting comments that either indicated the proposed 3.5 g/Bhp-hr NMHC
+ Nox standard (as well as the 3.15 g/Bhp-hr statutory level) was infeasible or that the statutory 3.15
g/Bhp-hr level was feasible. In opposition to the proposed 3.5 g/Bhp-hr standard, NGVC-AGA argued
that the statutory 3.15 g/Bhp-hr NMHC + Nox level was feasible They do not agree that reaching a
2.5 to 2 7 g/Bhp-hr Nox level (the approximate Nox level which EPA expects is necessary to achie\e
the 3.15 NMHC + Nox standard) is not feasible for clean diesel technology since Nox emission levels
below 2.0 g/Bhp-hr for heavy-duty diesel engines have already been demonstrated by researchers ai
Ricardo The Ricardo researchers applied exhaust gas recirculation (EGR) to a prototype diesel
engine, which was otherwise equipped with fuel injection, air-air intercooling, and electronic control
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
similar to those that will be used on many 1994-model commercial diesel engines. Also, NGVC-AGA
commented that the Acurex report1 reviewed essentially the same data, and concluded that transient
Nox levels less than 2.0 g/Bhp-hr were feasible with the use of EGR. Even lower emission levels
should be possible with the use of "clean" diesel fuel meeting California specifications. Furthermore,
NGVC-AGA suggested that EPA appears to have misinterpreted statements in the Acurex report.
Specifically, they commented that EPA stated that the report concludes that achieving the 2.5 g/Bhp-hr
level will require using a combination of one or more technologies that are in relatively early stages of
development (according to EPA) including very high pressure fuel injection, variable geometry
turbocharger, air-to-air aftercooler, optimized combustion chamber, electric unit injectors with
minimized sac volume, optimized fuel injection nozzles, fuel injection rate shaping, exhaust gas
recirculation and sophisticated electronic control of all engine systems. In fact, NGVC-AGA believes
that no "technological breakthroughs" are required, since they contend that every single one of these
technologies is already in use in one or more commercial diesel engine families. They also suggested
that to meet the 1994 and 1998 standards for conventional vehicles, most HDDEs will have to have
very high pressure fuel injection, optimized combustion, sophisticated electronic controls, and rate
shaping, with either electronic unit injectors or electronically controlled in-line injection pumps, and all
that would be required for such an engine to achieve 2.0 to 2.5 g/Bhp-hr Nox would be the addition of
EGR, and possibly a particulate trap.
In addition, NGVC-AGA also argued that enough clean diesel-fueled engine families will be
available to meet the expected needs of fleet operators in the Clean Fuel Fleet program since the 3.15
g/Bhp-hr NMHC + Nox level is feasible for most common engines used in HDVs less than 26,000 lbs
GVWR. Both GM and Navistar have engines (GM 6.2. 1 and Navistar 7.3 1) that use indirect
injection, which allows them to achieve low levels of Nox emissions with little penalty. (Common
mediuin-heavy duty engines, which include the Navistar DT466 and the Cummins 6B and 6c engines
use direct injection ) Furthermore, NGVC-AGA stated that EGR has already been used extensively on
light-duty diesel engines, including the light-duty version of the GM 6.2. 1. This engine (without
EGR) is also one of the most popular engines m the 8,500 - 26,000 lbs GVWR class. As mentioned
above, GM and Navistar's indirect-injection engmes tend to have low Nox emissions, and these
emissions can readily be lowered further by use of EGR -as GM has already done in the light-duty
versions of its engine. The incremental cost of EGR would be very small - essentially only the cost of
the EGR valve and ducts, or less than $50.
NGVC-AGA also believes that the EPA does not have the authority to relax the standard from
3.15 g/Bhp-hr NMHC + NOx level to the proposed 3 5 g/Bhp-hr NMHC + NOx level. They
commented that even if EPA were to find that diesels cannot achieve the 3.15 g/Bhp-hr level, the EPA
is not required to relax the standard, but instead has discretionary authority to do so Furthermore,
NGVC-AGA claimed that heavy-duty natural gas and methanol engmes have already been certified to
Nox + NMHC levels below 3.15 g/Bhp-hr, and such engines are currently being sold. The only
'Acurex Environmental Project Under Contract uiih California Air Resources Board. Final Report
"Technical Feasibility of Reducing Nox and Pa rum laic Emissions From Heavy-Duty Engines," Acurex
Environmental Project 8450, Contract No A132-()K> April 30, 1993 (found in the docket for ihi^
rulemaking).
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defense for relaxing the 3.15 statutory level would be if EPA were to find that the use of natural gas
or methanol engines in heavy-duty clean-fuel vehicles at 3.15 g/Bhp-hr NMHC + Nox was not cost-
effective compared to the use of diesels meeting the proposed relaxed standard of 3.5 g/Bhp-hr NMHC
+ Nox. Also, NGVC-AGA suggested that if Congress intended to mandate that EPA establish HD
CFV LEV standards that could be met by diesels, it would have done so instead of allowing EPA to
relax the level if determined it was necessary. They argue that at the time the CAA was written,
clean-fuel engines meeting the statutory standard were not yet commercially available, and Congress
must have had some doubt as to whether they would be available in time. EPA was thus given the
discretion to relax the standard if necessary to ensure that engines of some type would be available.
However, since HD clean-fuel engines meeting the 3.15 statutory level have been developed, certified,
and are now being sold in commerce, there is no need for EPA to exercise this discretionary authority.
In contrast, two commenters, EMA and Virginia, Maryland, and Delaware Association of
Electric Cooperatives (VMDAEC) agreed with EPA's proposed determination that a 3.15 g/Bhp-hr
standard is not technologically feasible for clean diesel-fueled engines. VMDAEC believes that a 3.15
g/Bhp-hr standard may preclude the use of diesel as an alternative fuel,and they suggested that because
section 245(b) of the CAA allows adoption of a less stringent standard for diesel-fueled engines, EPA
and manufacturers should combine efforts to establish a reasonable emission standard.
Analysis and Response to Comments
EPA agrees in part with NGVC-AGA's comments regarding the technological feasibility of
diesel engines meeting a 3.15 g/Bhp-hr NMHC + Nox standard, but reaches a different conclusion. As
a part of its assessment of the potential HDDE emission control technology, EPA studied the Acurex
report in depth. Like the Regulatory Support Document associated with this rule2, this report
concludes that to achieve a Nox-emission level of 2.5 g/Bhp-hr by 2000 (Nox levels needed to meet a
3.15 g/Bhp-hr NMHC + Nox standard3), diesel-fueled engines would need to be equipped with
advanced catalytic trap or EGR technologies. In addition, the 2.5 g/Bhp-hr level would also require
the use of a combination of some or all of the following emission control approaches for diesel-fueled
engines: very high pressure fuel injection, variable geometry turbocharging, air-to-air aftercooling,
optimized combustion, electronic unit injections with minimized sac volumes, optimized fuel injection
nozzles, rate shaping, exhaust gas recirculation and sophisticated electronic control of all engine
systems. Most of the devices described in the Acurex report are in relatively early stages of
development and would require extensive changes in heavy-duty diesel-powered engines compared to
today's designs. Acurex projects that achieving this level by 2000 would be possible, but it would
result in a 5 percent fuel economy penalty and a doubling of the engme price of a 1994 diesel-fueled
2U S. Environmental Protection Agency, Office of Mobile Sources, "Regulatory Support Document
Emissions Standards for Heavy-Duty Fleets," May 1991 (found in the docket for this rulemaking).
'Current certification data indicate that generally all diesel engine families have HC certification U
less than 0 5 g/Bhp-hr, so most reductions would have (o be achieved in Nox emissions. Thus, achie\ m>_
a 3.15 g/Bhp-hr NMHC + Nox standard would essentially require Nox-certification levels on the ordu
of 2.5 to 2.7 g/Bhp-hr.
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Clean Fuel Fleet and California Pilot Program
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engine. Based on the above assessment, EPA remains very doubtful that this standard could be met in
a cost-effective manner m time for the production of an adequate number of 1998 model year engine
families. Also, in response to NGVC-AGA comments that the 3.15 level is feasible for most common
engines today, EPA believes that although it is true that some versions of the necessary technologies
are in use today, the additional development effort needed to reach very low emission levels would be
very costly and would likely limit or eliminate the availability of heavy-duty diesel engines for the
CFF program.
Furthermore, EPA believes a review of the 1993 HDE federal certification results clarifies the
magnitude of the developmental task for manufacturers to achieve extremely low-emission levels,
especially for diesels. The data, which represents engines tested on federal certification fuel, indicates
that no current gasoline or diesel HDE family meets or is close to the 3.15 g/Bhp-hr standard on
federal certification fuel (for diesel and gasoline engines NMHC and HC are roughly equivalent). For
diesel engines, the 1993 heavy-duty engine federal certification results indicate that achieving the 3.15
g/Bhp-hr standard on federal diesel fuel would be extremely problematic for the majority of engine
families by 1998. Also, only one of 37 diesel engine families certified in 1993 is within one g/Bhp-hr
of the 3.15 level, most have combined HC and Nox certification levels of 5.5 g/Bhp-hr or less.
There are two existing sets of regulations that EPA believes will drive heavy-duty engine
technology towards low NMHC + Nox levels: the federal 1998 4.0 g/Bhp-hr Nox standard, and the
CARB LEV standard for diesel engines and mcomplete medium-duty vehicles of 3.5 g/Bhp-hr NMHC
+ Nox.4 EPA suggests that the development of the technology necessary to comply with the 4.0
g/Bhp-hr Nox standard, which is applicable to all HDEs, will make it more likely that a significant
number of light and medium diesel HDE families will be able to reach emission levels slightly below
4.0 g/Bhp-hr Nox on federal diesel fuel in the future, but it is unlikely that this federal standard will
force the development of technologies needed to achieve a 3.15 g/Bhp-hr NMHC + Nox standard on
such fuel (i.e., Nox levels less than 3.0 g/Bhp-hr) since there is no federal requirement to reach lower
levels.
Moreover, CARB's 3.5 g/Bhp-hr NMHC + Nox standard is the only other impetus driving
technology to achieve emission levels significantly below the 4.0 g/Bhp-hr Nox standard. Engine
manufacturers have stated that the CARB 1998 3.5 g/Bhp-hr NMHC + Nox standard for incomplete
medium-duty vehicles and diesel engines is feasible, and EPA agrees with CARB's expectation that
manufacturers will market a range of LEV diesel HDEs in California which will meet the California
standard. However, as with the federal 4.0 g/Bhp-hr Nox standard, EPA believes that it is unlikely the
current California standard will prompt the additional technology development needed to reach a 3 15
g/Bhp-hr NMHC + Nox level since there is no requirement to reach levels below 3.5 g/Bhp-hr NMHC
+ Nox. This is especially true for engines intended for vehicles between 14,000 and 26,000 pounds
GVWR, which are covered by the Clean Fuel Fleet Program but not the current CARB LEV program
EPA believes it is appropriate to look al the demand for heavy-duty CFVs as a relevant faciei
4Beginning with the 1995 model year, CARB's medium-duty vehicles include vehicles with a GVW k
of 14,000 pounds or less.
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Clean Fuel Fleet and California Pilot Program
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when determining whether a particular combined NMHC + Nox standard for diesel-fueled vehicles is
technologically feasible under section 245(b)(1). For the reasons discussed above, EPA believes that
achieving a level of 3.15 g/Bhp-hr NMHC+Nox for even a small selection of HDDEs by 1998 will be
a very difficult task. Manufacturers will need to invest significantly in research and accelerated
technology development, and any engmes which reach production will be more costly (in terms of
both engine price increase and fuel economy penalty, as discussed above), especially based on the
relatively small demand that will be created by the Clean Fuel Fleet Program. In the absence of
mandated production, EPA believes that a technological effort of this magnitude is likely to be
undertaken by engine manufacturers only under circumstances of a certain, substantial market.
The CFF program contains no authority for a production mandate. (As discussed below, EPA
disagrees with EMA's claim that the definitions adopted by EPA for "centrally fueled" and "capable of
being centrally fueled" will cause a large percentage of engme families to be within the scope of the
HD CFV standards.) Thus, EPA believes that the size and certainty of the market is central to whether
diesel engmes will be developed to meet the requirements of heavy-duty fleets covered by the fleet
program. However, only a small number of heavy-duty vehicles will be needed by fleets for their fleet
program purchase requirements. For example, during each year of the fleet program EPA estimates
that a maximum of only about 2 percent (10,000) of total nationwide new heavy-duty diesel vehicles
will be purchased by fleet operators to meet the Clean Fuel Fleet Program requirements.5 This
projected market decreases by about 25 percent if California opts out of the Clean Fuel Fleet Program;
other potential opt outs by additional states may reduce the market to under one percent of nationwide
heavy-duty diesel engine sales (or under about 5000 vehicles). By comparison, based on the
implementation schedule of CARB's LEV program, the annual market (30,000) for vehicles required
to meet CARB's LEV standard for diesel engines and incomplete medium duty-vehicles of 3.5 g/Bhp-
hr NMHC+Nox is approximately three to six times as large as the potential federal clean diesel-fueled
market.6 CARB's program incorporates a phased-in percentage sales mandate for this larger number
of vehicles.
EPA is concerned that engme manufacturers will not consider a HDE market of the size
represented by the CFF program to be sufficient to justify the major voluntary technological
development efforts necessary to reach a 3.15 g/Bhp-hr standard, especially when efforts are also
underway to meet the 4.0 g/Bhp-hr federal Nox standard and the 3.5 g/Bhp-hr NMHC + Nox
California standard. Even if some manufacturers do launch such an effort, the likely higher cost and
possible fuel economy penalty may make it much more difficult for diesel engme producers to
'U.S. Environmental Protection Agency, Office of Mobile Sources, "Estimated Number of Fleet
Vehicles Affected by the Clean Fuel Fleet Program." Memorandum from Shen Dunatchik to Docket A-91 -
25, June 11, 1991.
6Heavy-duly vehicle population projections lor the California LEV program are based on ihe
following (1) light heavy-duty production reports submitted to the U.S. Environmental Protection Agenc\
for model year 1991 and (2) New Truck Registrations b\ Manufacturer and State data from the "AAMA
Facts and Figures 1993" (page 27) that shows California truck sales to be 10 percent of nationwide truck
sales.
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Clean Fuel Fleet and California Pilot Proeram
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compete for sales with gasoline or alternative fueled engine options which may be available. Since
developing and producing vehicles for the fleet program is, by statute, voluntary, EPA believes that it
is very possible that, with a very low emission standard, an inadequate offering of diesel engines will
be produced for the clean fuel fleet program. Even though, there are existing CNG engines that have
achieved a 3.15 g/Bhp-hr standard, EPA also believes that the Act is clear in its intention that EPA
may design the fleet program such that clean diesel vehicles can participate. Furthermore, in
determining whether the 3.15 g/Bhp-hr NMHC + Nox standard is feasible for clean diesel-fueled
heavy-duty engines, EPA believes that the Act does not require a determination that the standard is
feasible for any smgle diesel engine family, but rather that it is feasible for at least enough diesel
engine families such that fleet operators have enough choice to meet their requirements under the
Clean Fuel Fleet Program. EPA thus concludes that a standard of 3.15 g/Bhp-hr is not feasible for
heavy-duty clean diesel-fueled engines taking into account costs, lead time, durability, and other
relevant factors, and thus, EPA will not mandate a 3.15 g/Bhp-hr standard for HD CFVs in the CFF
program.
b. Feasibility of Proposed 3.5 g/Bhp-hr NMHC + NOx CFV LEV Standard
Summary of Comments
Also, in opposition to the proposed 3.5 g/Bhp-hr NMHC + Nox standard, manufacturers
argued extensively that this 3.5 standard is not feasible for clean diesel-fueled engines (along into
account durability, costs, leadtime, safety, and other factors. First, EMA argued that EPA cannot base
its analysis of technological feasibility on the assumption that the yet unproven technology necessary
to reach the 4.0 g/BHP-hr standard in 1998 will suffice to lower Nox an additional 25 percent.
Second, EMA argued that it is a mistake to assume that heavy-duty engines used in centrally fueled
fleet operations represent a small segment of manufacturers' product offerings, and it is unlikely that
engine manufacturers will be able to limit the work necessary to comply with a CFV standard only to
a narrow product offering. Third, EMA stated that CARB's 3.5 g/BHP-hr LEV standard only applies
to 25 percent of 1998 model year medium-duty vehicles sold in California and does not apply to
vehicles greater than 14,000 lbs. GVWR. EMA states that, for these reasons, the CARB LEV
standard is not representative of the broad range of vehicles up to 26,000 lbs. GVWR included in the
CFF program.
Moreover, EMA believes that EPA has failed to recognize the effect of low aromatic, high
cetane fuel on vehicle emissions in proposing a 3 5 g/Bhp-hr NMHC + Nox standard. EMA stated
that EPA refers to CARB's proposed new medium-duty LEV standard to justify the proposed standard,
and the technological feasibility of CARB's medium-duty LEV standard is directly linked to the use of
California's unique diesel fuel specification (aromatics content is limited to 10 percent, or the fuel has
been shown to provide equivalent emission reductions) Therefore, EMA, as well as Cummins,
suggested that the proposed standard may be feasible if EPA were to require the use of California
diesel fuel in nonattainment areas covered by the CFF program (low aromatic fuel) or allow engine
manufacturers to conduct all certification. SEA and m-use testing (verification testing) on California
diesel fuel These commenters recommended the use of California diesel fuel for certification while
recognizing that those vehicles may operate on federal luel outside of California EMA and Cummins
believe that EPA can account for the emissions difference resulting from the differences between the
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Clean Fuel Fleet and California Pilot Prosram
Summary & Analysis of Comments
certification fuel (i.e., California diesel fuel) and the expected operating fuel (i.e., federal diesel fuel)
by calculating an emissions offset factor that is based on the differences between the two fuels. EMA
suggested that an offset in the range of 0.59 to 0.66 g/Bhp-hr NMHC + Nox be used for determining
the ui-use emissions of a HD CFV operated on federal fuel but certified on California fuel. Cummins
recommends that an offset factor of 0.55 g/Bhp-hr be used in determining m-use emissions of such
HD CFVs. EMA commented that EPA should set the HD CFV standard at 4.2 g/Bhp-hr NMHC +
Nox if California diesel fuel is not required for all testing because the actual offset will vary with
different engmes. Both EMA and Cummins believe that harmonization of standards and fuels with
California is the most cost-effective and technically appropriate decision for EPA. Furthermore, these
commenters stated that adjusting the HD CFV LEV standard to a less stnngent standard than 3.5
g/Bhp-hr and not allowing certification on California fuel would greatly complicate the certification
process for HD CFVs since it would require additional work, re-calibration, and re-testing at additional
costs.
In contrast, API and Texaco opposed the use of California-type fuel for certification, SEA, and
m-use testmg to demonstrate compliance with the proposed 3.5 g/Bhp-hr HD CFV standard. They
believe it is not necessary since certification, SEA, and in-use compliance testing of heavy-duty
engines outside of California beginning with the 1994 model year should be performed with diesel fuel
meeting the federal requirements of a maximum sulfur content of 0.05 weight percent and a minimum
cetane mdex specification of 40.
Analysis and Response to Comments
For the reasons discussed above, the major force driving light and medium heavy-duty diesel
engine emissions to levels below 4.0 g/Bhp-hr will be the CARB LEV program. As explained below,
EPA recommends a combined NMHC + Nox emission standard of 3.8 g/Bhp-hr for heavy-duty clean-
fuel engines certified on federal diesel certification fuel. EPA is, however, allowing manufacturers to
certify heavy-duty clean-fuel engines to a standard of 3 5 g/Bhp-hr on California diesel certification
fuel, which EPA believes for a given engine is approximately equal in stringency to the 3.8 g/Bhp-hr
standard usmg federal diesel certification fuel, as described below. The level of stringency represented
by these standaids should be achievable for a sufficient number of diesel engine families to meet fleet
operator's requirements with fairly straightforward technological improvements and without a serious
fuel economy penalty. EPA believes this approach will assure that the same engmes that are
developed and produced for the California LEV program will also be acceptable to fulfill the
requirements of the Clean Fuel Fleet Program
EPA also recognizes that differences between California and federal certification and in-use
diesel fuels may cause a difference in emission rates CARB limits the aromatics content of the test
fuel to a maximum of ten percent, while federal test fuel may contain as much as 35 percent
aromatics There is evidence to suggest that the use of federal test fuel can result in higher NMHC +
Nox emissions than the use of CARB fuel in the same engine Apparently, this occurs because the
higher aromatic content of the fuel reduces its ceunc i.tung and thus combustion is slightly less
enhanced Data reported in the NPRM for a 1991 pmtot\pe DDC Series 60 heavy-duty engine
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
showed this difference to be in the range of 0.3 g/Bhp-hr offset.7
In addition to the analysis of the 1991 prototype heavy-duty diesel engine referenced in the
NPRM, EPA has used a similar analysis to examine diesel fuel effects based on data presented in a
study performed on a 1993 prototype Navistar Diesel DTA 466 medium heavy-duty engine.8 As had
been done in the earlier analysis, EPA compared federal and California diesel fuels on the basis of
aromatic percent and cetane number. EPA used the specified aromatic levels of 10 percent for
California test fuel and 35 percent for federal test fuel and natural cetane numbers of 50 and 46 for
typical California and federal certification fuels, respectively.9 Based on the three most recent national
m-use diesel fuel surveys from AAMA (Winter 1993, Summer 1993, and Winter 1994, found in the
docket for this rulemaking), the above aromatic levels and natural cetane numbers from California and
federal certification diesel fuels are representative of the aromatic levels and cetane numbers found in
typical in-use diesel fuels used in California and the rest of the country. Specifically, average
California and non-California natural cetane numbers range from 43.8 to 51.5 and from 44.2 to 46.7,
respectively. An API gravity number typical of both test fuels of 36 degrees was used. The following
regression equations were developed in the study conducted on the 1993 engine for total hydrocarbon
(THC) and Nox:
THC [g/Bhp-hr] = 0.819 - 0.01942 * (Natural Cetane) + 0.01159 * (API)
Nox [g/Bhp-hr] = 6.593 + 0.01183 * (SFC Aromatics %) - 0.02497 * (Natural
Cetane) - 0.02365 (API)
Substituting the values selected above for percent aromatics and cetane numbers into these
equations, the Agency calculated a THC + Nox offset of about 9.7 percent. Applying this percent
offset to the 3 5 g/Bhp-hr standard for CARB diesel fuel, the EPA analysis calculated that the offset
would be about 0.34 g/Bhp-hr THC + Nox. (This analysis assumed that the offset would apply
7 "Effects of Fuel Aromatics, Cetane Number, and Cetane Improver on Emissions from a 1991
Prototype Heavy-Duty Diesel Engine," T. Ullman, R. Mason, and D. Montalvo, Southwest Research
Institute, SAE Paper 902171., U.S. Environmental Protection Agency, Office of Mobile Sources, "Effect
of Test Fuel Differences on NMHC + Nox Emissions," Memorandum from Michael Samulski to the
docket for this rulemaking, February 23, 1993
'"Diesel Fuel Property Effects on Exhaust Emissions from a Heavy Duty Diesel Engine that Meeis
the 1994 Emissions Requirements," C. McCarthy, Amoco Oil Co , W. Slodowske, E. Sienicki, and R. Jass
Navistar InternaUonal Transportation Corp., SAE Paper 922267
'The cetane numbers used in the EPA analysis on the 1993 heavy-duty engine were based on iho
following- 1) "Development of the First CARB certified California Alternative Diesel Fuel". M Nikani.im
SAE Paper 930728, 2) Section 2282, Title 13 California Code of Regulations procedure for certil\mv.
diesel fuel formulations resulting in equivalent emissions reductions and 3) Cummins Engine Compare
and Caterpillar diesel fuel formulations for federal diesel fuel These cetane numbers are natural cciam
numbers (without cetane improver).
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
equally whether THC or NMHC was being considered, EPA has no data to indicate that the small
methane emissions component in diesel emissions would affect the relative behavior of the engine on
the two fuels). If the available numbers from the recent AAMA surveys for aromatics level and
natural cetane number are substituted Into the THC and Nox equations, a percent offset smaller than
the 9.7 percent offset results in each case.
Thus, EPA concludes that diesel engines certified to a 3.5 g/Bhp-hr level on California diesel
fuel would, for typical engines, result in NMHC + Nox emissions of approximately 3.8 g/Bhp-hr for
the same engines operated on federal diesel fuel, confirming the estimate made in the NPRM. In their
comments engine manufacturers quoted the same data that EPA has used for the 1991 and 1993
prototype diesel engines, but used different assumptions for the cetane number for in-use diesel fuel.
Clearly, EPA believes that the aromatic levels and cetane numbers used by EPA are representative of
certification and in-use fuels, and thus, it is reasonable to conclude that EPA's analysis of the offset is
valid. Also, the industry analysis did not adjust the offset proportionally to account for the much
lower emissions of CFVs as compared to the current engine which generated the test data. In their
comments, they concluded that the offset between federal certification fuel and California certification
fuel may be more in the range of 0.55 - 0.66 g/Bhp-hr. EPA has examined the assumptions used in
the industry analysis and concluded that the EPA analysis is a more appropriate approach for
determining the expected emissions offset. While this conclusion is based on data from a single
engine, EPA believes that the 1993 engine is of the appropriate size (medium heavy-duty) from which
to draw a conclusion for this program, and that the study was done on a meaningful array of diesel
test fuels. It is likely that if similar data were collected on other engines, somewhat different values
for the CARB/federal fuel offset might be observed. In some cases the effect would either be slightly
higher or lower depending on engine technology and fuel characteristics. Until such a time when
additional data becomes available, EPA will assume that offsets for other heavy-duty diesel engines
would range on either side of the 0.34 g/bhp-lir level EPA has developed for the 1993 engine. Thus,
EPA believes that its analysis reasonably accounts for potential fuel and engine variability and that the
0.34 g/Bhp-hr value represents a reasonable estimate for the average emissions offset between federal
certification fuel and California certification fuel.
Further, because EPA is reasonably confident that in-use emissions of an engine certified at
3.5 g/Bhp-hr on California fuel will result in emissions in the range of 3.8 g/Bhp-hr on federal fuel,
EPA will grant a federal certificate of conformity to a manufacturer which demonstrates compliance
with the 3 5 g/Bhp-hr standard on California certification fuel. (The federal certificate will be issued
developed by EPA according to current certification procedures.) While it is possible that individual
engines certified on California fuel may experience a slightly different offset when operated on federal
diesel fuel (e.g., when a cetane number is much different between the fuels), EPA believes that this
will be the exception and that in-use emissions on federal diesel fuel will average about 3 8 g/Bhp-hr
The use of federal fuel in engmes certified on California fuel is consistent in this case with the fuel
use provisions of sections 246(b) and 241(2), since EPA has concluded that such engines indeed
comply with the clean fuel vehicle requirements when operating on federal diesel fuel.
As another way of harmonizing the CARB LEV program and the CFF program to ensure a
sufficient number of HDDEs will be available by 1998 for the fleet program. EPA will only test
engine families which were certified to CFV standards on California diesel fuel on diesel fuel meetmv:
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
California specifications during any Selective Enforcement Audit (SEA) testing or in-use recall
enforcement testing. The Agency believes that if manufacturers of HD CFVs certified on California
fuel perceive that their engines may be subject to later EPA testing on federal diesel fuel, then they
may desire to perform additional testing of these engines on federal certification diesel fuel for the
purpose of assuring themselves of in-use compliance on federal diesel fuel. This approach to SEA and
in-use recall testing should assure manufacturers that they will not need to perform any additional
testing at certification beyond that required for California certification. Fuel meeting California diesel
test fuel specifications is an acceptable test fuel under the FTP because it meets the federal fuel
specifications. This policy of the Agency using fuel meeting California diesel test fuel specifications
for SEA and recall testing applies only to CFVs. If the Agency becomes aware of changed
circumstances which indicate that this policy is inappropriate, the Agency reserves the right to
discontinue this policy.
With regard to the feasibility of the 3.5/3.8 g/Bhp-hr standard, as discussed above in the
section concerning the feasibility of 3.15, EPA believes there are two existing sets of regulations that
will drive heavy-duty engine technology towards low NMHC + Nox levels: the federal 1998 4.0
g/Bhp-hr Nox standard, and the California Air Resources Board (CARB) LEV standard for diesel
engmes and incomplete medium-duty vehicles of 3.5 g/Bhp-hr NMHC + Nox. EPA believes that
development of the technology necessary to comply with the 4.0 g/Bhp-hr Nox standard will make it
more likely that a significant number of light and medium diesel HDE families will be able to reach
emission levels slightly below 4.0 g/Bhp-hr Nox on federal diesel fuel in the future. Moreover,
CARB's 3.5 g/Bhp-hr NMHC + Nox standard is driving technology to achieve emission levels
significantly below the 4.0 g/Bhp-hr Nox standard. Engine manufacturers have stated that the CARB
1998 3.5 g/Bhp-hr NMHC + Nox standard for incomplete medium-duty vehicles and diesel engines is
feasible, and EPA agrees with CARB's expectation that manufacturers will market a range of LEV
diesel HDEs in California which will meet this California standard, which corresponds to the HD CFV
NMHC + Nox standard of 3.8 g/Bhp-hr on federal fuel as indicated above. Moreover, eleven of the
37 diesel engine families certified in 1993 on federal diesel fuel are within one g/Bhp-hr of the 3.8
g/Bhp-hr NMHC + Nox level (equivalent to Nox-certification level of 3.3 g/Bhp-hr), indicating to
EPA that a standard in this range could likely be achieved by a variety of diesel engmes on federal
diesel certification fuel.
Also, Acurex projected that in 1999 diesel-fueled engines equipped with either an oxidation
catalyst and EGR or a catalytic trap and EGR could achieve a Nox-emission level of 3.0 g/Bhp-hr
(approximately equivalent to 3.5 g/Bhp-hr NMHC + Nox standard). EPA believes that this projection
supports the feasibility of a 3.5/3.8 g/Bhp-hr NMHC + Nox standard for heavy-duty CFVs in 1998.
The Acurex projection is based on an assessment for all HDDEs. whde the HD CFV standard need
only be met by one subset of all HDDEs Thus, this Acurex projection that 3.0 g/Bhp-hr Nox levels is
possible for all HDEs in 1999 supports EPA's position that a similar Nox-emission level can be
achieved by at least some engines (light and medium heavy-duty engines) in 1998 or earlier.
Thus. EPA is promulgating a HD CFV standard ul 3 8 g/Bhp-hr NMHC + Nox (3.5 g/Bhp-hr
on California fuel). This standard harmonizes as completely as possible the federal standard with
CARB's NMHC + Nox LEV standard for diesel engines and incomplete medium-duty vehicles EPA
believes that the effect of this harmonization will make the overall national market for clean HDDEs
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
significantly larger than it would otherwise be with either program alone and will thus assure that
clean HDDEs will be available in adequate model offerings by 1998 for the Clean Fuel Fleet Program.
In addition, EPA disagrees with the comment from API and Texaco that there is no need to
use California diesel fuel for certification and enforcement testing since federal low-sulfur diesel fuel
(the federal diesel fuel used in the EPA offset analysis above) will be available in the 1994 model
year. EPA believes, as explained above, that for clean HDDEs there is a need for allowing
manufacturers to use California diesel fuel since the use of federal low-sulfur fuel results in emissions
of approximately 0.3 g/Bhp-hr more NMHC + Nox in comparison to California fuel.
2. Ultra Low-Emission Vehicle (ULEV) Standards
Summary of Issue and Comments
One commenter, GM, made comments in opposition to the proposed HD CFV ULEV standard.
GM questioned the feasibility of the HD CFV ULEV standard (2.5 g/Bhp-hr NMHC + Nox, 7.2
g/Bhp-hr CO, 0.05 g/Bhp-hr particulate, and 0.025 g/Bhp-hr formaldehyde) since the ability of HDEs
to comply with these requirements has not been demonstrated. Also, GM stated that the federal HD
CFV ULEV CO standard does not correspond to the California ULEV incomplete medium-duty CO
standard because the California standard only applies to vehicles up to 14,000 lbs GVWR.
Furthermore, GM also stated that the heavy-duty CO standards for conventional gasoline engines are
divided into two categories. 1) for 8,501-14,000 lbs. GVWR category, the Tier 0 CO standard is 14.4
g/Bhp-hr; 2) for 14,001-26,000 lbs. GVWR category, the CO standard is 37.1 g/Bhp-hr. GM
commented that comparable CO standards for ULEV heavy-duty gasoline engines therefore must also
have two CO standards; 1) one for engines certified for vehicles in the 8,501-14,000 lbs. GVWR
category and 2) one for engines certified for vehicles in the 14, 001 - 26,000 lbs. GVWR category
GM believes it is an oversight that EPA addressed only the CO standard for 14,000 lbs. GVWR and
below, therefore, they stated that EPA must propose a CO standard for ULEV heavy-duty engmes
certified for vehicles 14,000 lbs. GVWR and above.
Analysis and Response to Comments
EPA is adopting the proposed HD CFV ULEV standards (described above). Section 246(0(4)
of the CAA requires EPA to promulgate emission standards for ULEVs and ZEVs, for the purpose of
determining fleet program credits. The provision states that the standards:
shall be more stringent than those otherwise applicable to clean-fuel vehicles
under this part....The standards., for [light-dutyj vehicles...shall conform as
closely as possible to standards which are established by the State of California
for ULEV and ZEV vehicles in the same class. For vehicles of 8.500 lbs.
GVWR or more, the Administrator shall promulgate comparable standards for
purposes of this subsection.
EPA interprets this comparability criteria to mean that ULEV and ZEV standards for heavy-
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
duty engines should require approximately the same percentage of emission reduction compared to
heavy-duty CFV LEV standards as light-duty CFV ULEV and ZEV standards require compared to
light-duty CFV LEV standards. Under this provision, EPA must determine the appropriate level for
the heavy-duty ULEV and ZEV standards.
EPA also believes it is appropriate to take California's ULEV and ZEV standards into
consideration and attempt to harmonize the federal and California standards where possible. As
mentioned above in the section pertaining to the feasibility of the HD CFV LEV standard, EPA
believes such harmonization is valuable because it helps create a single larger market for heavy-duty
ULEVs and ZEVs rather than two smaller markets. A single larger market makes it more economical
for manufacturers to produce heavy-duty ULEVs and ZEVs, which makes it more likely that
manufacturers will choose to produce vehicles that can participate in the federal program. (The federal
program does not have a sales mandate for manufacturers, so their participation is voluntary and
controlled, in part, by market demand for their products.)
EPA also believes it has authority to consider harmonization of federal heavy-duty ULEV and
ZEV standards with California mcomplete medium-duty and diesel engine ULEV and ZEV standards
in setting the federal standards.10 As explained above, EPA interprets "comparable standards" to
mean that heavy-duty CFV ULEV and ZEV standards must be comparable to light-duty CFV ULEV
and ZEV standards. Since the Act requires EPA to establish federal light-duty ULEV and ZEV
standards that conform as closely as possible to California's light-duty ULEV and ZEV standards,
harmonization of the federal heavy-duty ULEV and ZEV standards with California incomplete
medium-duty and diesel engine ULEV and ZEV standards could be part of the comparability
determination. In addition, the direction of section 246(f)(4) to set "comparable standards" gives EPA
some discretion in establishing ULEV and ZEV standards. EPA believes it is appropriate to consider
California's standards as a relevant factor in exercising this discretion. EPA believes that, since the
federal HD ULEV and ZEV standards are voluntary credit-generating standards, their intended purpose
is primarily to provide compliance flexibility for manufacturers and fleet operators. The Agency's
goal then, in selecting these standards, is to provide the maximum flexibility allowable under section
246 (f)(4) of the Act, while ensuring that there will be positive impacts on the environment. EPA
believes that the proposed ULEV standard meets these criteria.
EPA is aware that the CO standard for heavy-duty gasoline-fueled LEVs below 14,000 lbs
GVWR is 14 4 g/Bhp-hr, while the CO standard for heavy-duty gasoline-fueled LEVs above 14,000
lbs GVWR is 37.0 g/Bhp-hr. However, the CO LEV standard for all heavy-duty diesel-fueled LEVs
is 15 5 g/Bhp-hr. EPA does not believe that the "split" CO standard for heavy-duty gasoline-fueled
LEVs requires promulgation of a similar "split" standard for heavy-duty ULEVs. Section 246(f)(4)
requires EPA to set heavy-duty ULEV standards that are comparable to, not identical to, light-duty
ULEV standards. As stated above, EPA interprets the comparability requirement in Section 246(f)(4)
to require heavy-duty ULEVs to achieve reductions in emissions that are comparable to those achieved
by light-duty ULEVs.
'"Beginning with the 1995 model year, CARB s medium-duty vehicles are those vehicles with a
GVWR of 14,000 pounds or less.
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Clean Fuel Fleet and California Pilot Program
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EPA is today promulgating a CO standard of 7.2 g/Bhp-hr for heavy-duty ULEVs. This
standard achieves a reduction in CO emissions of approximately 50% compared to the heavy-duty
diesel LEV standard, a reduction that is comparable to the 50% reduction in CO emissions achieved
by light-duty ULEVs compared to light-duty LEVs. Further, the CO standard for heavy-duty ULEVs
is the same as California's CO standard for incomplete medium duty and diesel ULEVs. As stated
above, SecUon 246(f)(4) allows EPA to consider California's standards when setting federal ULEV
and ZEV standards, and to attempt to harmonize the federal ULEV and ZEV standards with
California's standards.
Regardless of the level at which the heavy-duty ULEV CO standard is established, EPA
expects that manufacturers will need to use catalyst technology to meet the heavy-duty ULEV NMHC
+ NOx standard of 2.5 g/Bhp-hr. With regard to engines used in vehicles over 14,000 lbs GVWR,
EPA recognizes that the split in the CO emission standard for gasoline-fueled HDEs (14.4 g/Bhp-hr
for engines in vehicles less than or equal to 14,000 lbs GVWR and 37.1 g/Bhp-hr for engines in
heavier vehicles) allowed the development of two basic control technology approaches (catalyst and
non-catalyst), respectively. A review of 1993 gasoline-fueled HDE certification results (for the >
14,000 lbs GVWR weight category) indicates that four of six configurations certified did not employ
catalysts. These four configurations had CO certification levels ranging from about 17 - 25 g/Bhp-hr
with combmed HC+NOx levels of 4.8-5.6 g/Bhp-hr. The two configurations which certified using
catalysts had CO levels well below the 14.4 g/Bhp-hr statutory level with HC+NOx levels of about 5,0
g/Bhp-hr. However, even if the CO standard were set at a higher level for engines used in the
>14,000 lb GVWR vehicles, the 2.5 g/Bhp-hr NMHC + NOx ULEV standard would still likely require
the use of catalysts on all affected engines. The only variable would be the degree of air injection
required to meet the CO standard. The affect of air injection on catalyst durability was an unresolved
technical issue in 1984 when the current HDE HC and CO emission standards were promulgated.
After 10 years, the market has changed and catalyst technology has improved. In fact, as mentioned
above, two gasoline engine configurations used in vehicles over 14,000 lbs GVWR have been certified
with catalysts and catalysts are now being considered for the very lean diesel engine applications.
In setting the standard, it is also important to note that the HD LEV standards are to be set at
a level diesel engmes can meet, and most engines sold in the weight category greater than 14,000 lbs
GVWR are diesel-fueled. The emission standards are not split at 14,000 lbs for diesel engines as they
are for gasoline. Furthermore, since the federal HD ULEV standards are voluntary, credit-generating
standards, and HD CFV ULEVs are eligible to receive TCM exemptions, a relatively stringent HD
CFV ULEV CO standard is appropriate.
Thus, given the language of the statute regarding comparability of federal heavy-duty ULEV
and ZEV standards to CARB ULEV and ZEV standards and the light-duty CFV ULEV and ZEV
standards and the improvement in technology already achieved and achievable by 1998, it is
reasonable to establish a CO emission standard for HD ULEVs which is more stringent than
conventional levels. For the reasons discussed above EPA believes that a single CO ULEV standard
for all HD CFVs is appropriate, rather than a split standard at 14.000 lb GVWR, and is therefore
promulgating a single CO ULEV standard as proposed
3. Heavy-Duty Dual- and Flexible-Fuel Emission Standards
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
Summary of Issue
EPA requested comment m the proposal on the appropriateness, desirability, and authority for dual-
and flexible-fuel emission standards for clean-fuel HDEs. EPA also requested that those commenters
suggesting separate standards for flexible- and dual-fuel HDEs should suggest an approach to setting
those standards as well as appropriate emission standards.
Summary of Comments
NGVC-AGA commented that in the case of light-duty vehicles, the preference for dual- and
flexible-fuel vehicles was explicitly accommodated by Congress, which established less-stringent
NMOG standards for flexible- and dual-fuel vehicles when operating on conventional fuel. NGVC-
AGA believes both dual-fuel and flexible-fuel technologies offer great promise for expanding the use
of clean-fuel vehicles during the interim period when the alternative fuel supply infrastructure is still
being developed. Therefore, they suggested that it would be good policy, and consistent with the
intent of Congress, for EPA to accommodate these technologies by establishing less-restrictive
emissions standards for heavy-duty dual- and flexible-fuel engines when operating on conventional
fuels, particularly when it is mandated that clean alternative fuel be used when the vehicle is operating
in a covered area.
Specifically, NGVC-AGA recommended that dual- and flexible-fuel CFVs meeting the basic
heavy-duty CFV LEV standard be required to meet the applicable heavy-duty conventional engine
standard when operating on conventional fuel and that dual- and flexible-fuel vehicles certifying to the
ULEV standard should be required to meet the LEV standard on conventional fuel. They beheve this
approach would make it possible for a conventional vehicle converted to dual- or flexible-fuel
operation using a clean fuel to qualify as a CFV, without having to modify the conventional-fuel
emission control system. Also, NGVC-AGA suggested that this would be consistent with
Congressional intent to allow converted vehicles to qualify as CFVs, as well as with the market reality
that many CFV purchases will require the abihty to operate on conventional fuels when operating
outside of covered areas and away from areas where clean alternative fuel is available.
Analysis and Response to Comments
EPA is not today adopting a set of emission standards for flexible- and dual-fuel heavy-duty
vehicles. Section 245 does not specifically require such standards. Section 243(d) of the Act
prescribes emission standards for flexible- and dual-fueled light-duty vehicles and trucks which are
being adopted in this rulemaking. EPA believes that the directive of section 243(g) that "nothing in
this section shall apply to heavy-duty engines" makes it clear that section 243(d) does not require EPA
to establish flexible- and dual-fueled standards for heavy-duty engmes.
Even, if EPA has authority to promulgate such standards an issue we do not discuss here
EPA does not consider it appropriate to exercise thai authority at this time As described in the
proposal, EPA believes separate NMHC standards for each fuel are not necessary for flexible- or clu.il-
fuel HD CFVs since similar behavior of NMHC (or the equivalent (NMHCE)) is expected for all fuel
types. In addition, EPA believes that heavy-duty vehicles operated on conventional gasoline or diesei
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
fuel will be able to comply with the CFV standards by 1998, and thus, there is not a compelling
technical reason to have slightly less stringent standards for the vehicle when it is operated on
conventional fuel. In this final rulemaking, EPA is setting the HD CFV emission standards at a level
that conventionally-fueled vehicles (i.e. diesels) are likely to be able to meet. Therefore, EPA believes
it would be inappropriate to allow a heavy-duty CFV to meet a less stringent standard on conventional
fuel simply because the vehicle is operating on an alternative fuel.
4.	Averaging, Trading, and Banking
Summary of Issue and Cnmnn»ms
Two commenters expressed concern with the proposed manner in which HD CFVs would be
treated in the existing averaging, trading, and banking program. EPA proposed that HD CFVs not be
included by manufacturers in the HD AT&B program since their in-use emission reductions will be
accounted for in the CFF program; to also account for these reductions at the manufacturer level
would "double count" the reductions. EMA suggested that there might be a way to include CFVs in
the AT&B program, but they offered no suggestions in this regard.
Also, ETC encouraged EPA to make the maximum credit incentive available to fleet operators
to encourage use of heavy-duty ZEVs. They believe that since electric vehicles are not included in the
current AT&B program for heavy-duty engines (58 FR 15781, March, 1993), concerns regarding
potential double counting of emission reductions due to the use of heavy-duty ZEVs are reduced.
ETC suggested that any label affixed to a HD ZEV in compliance with the requirements of 40 CFR
§86.095-35 should make it clear to a potential covered fleet operator that no double counting will
result if the ZEV is credited toward compliance and used to generate credits in the fleet program.
Analysis and Response to Comments
EPA believes that since commenters offered no specific AT&B program nor any
documentation to show the environmental and economic benefits of using such a program, EPA's and
proposed approach should prevail. CFV HDEs in the CFF program must be certified under Part 88,
and those engines will not be permitted to participate in AT&B programs since emission reductions
associated with the use of such engines should be targeted to the urban areas where HD CFVs operate.
However, it will be possible to certify the same vehicle under part 86 and obtain AT&B credits.
Also, EPA disagrees with ETC's implication that there may be confusion about whether
emission reductions associated with ZEVs are being accounted for under Part 86 or Part 88 since
ZEVs cannot be certified under part 86. The proposed approach permits electric vehicles to certify (as
CFVs) under Part 88 but not under Part 86, the manulacturer of such an electric vehicle would affix a
permanent label that indicates that the vehicle or engine meets the requirements of Part 88 but not
necessarily the requirements of Part 86. EPA is promulgating this approach.
5.	Credit Exchange Programs for Manufacturers of Heavy-Duty Clean-Fuel Fleet
Vehicles
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
Summary of Issue/Comments
In the proposal, EPA requested comment regarding a credit exchange program that would
permit manufacturers to use credits obtamed through AT&B programs to qualify engines as LEV
engines even though they do not meet the LEV standards. One commenter, PennDOT, commented
that this provision should not be permitted since it is inconsistent with the intent of the Clean Fuel
Fleet program to encourage the manufacture, purchase, and use of vehicles that can use clean
alternative fuels. PennDOT agrees with the NPRM that this practice could mean that credit-using and
credit-generating engines would not be located in the same nonattainment area and therefore is
inconsistent with the CAA requirement to limit purchase credit exchanges among fleet owners to
within the same nonattainment area.
Analysis and Response to Comments
EPA has decided not to pursue a credit exchange program for manufacturers of HD CFVs.
The programs appeared to be administratively burdensome with minimal economic and emission
benefit and questionable legality, and as indicated above, there was no support expressed in the
comments for these programs.
III. Conversions
A. Definition of "Person Who Converts": Certification, Warranty, and Liability Provisions
for Aftermarket CFV Conversion Configurations
Summary of Issue
Section 247(c) states that "any person who converts conventional vehicles to clean-fuel
vehicles .... shall be considered a manufacturer for purposes of sections 206 and 207 and related
enforcement provisions." To implement this requirement EPA considered two options in the NPRM
regarding the definition of the "person who converts".
Under the first option, the person who converts would be defined as the person(s) who installs
conversion equipment on a vehicle in order to convert the vehicle into a CFV. Thus, such a person
would be required to demonstrate that the converted vehicle configuration complies with the CFV
standards by satisfying the certification requirements in order to receive a federal certificate of
conformity. Under the second option, the person who converts would include the conversion kit
manufacturer as well as the installer of the kit. In the second option, the kit manufacturer and the
installer would both have responsibilities in demonstrating that a vehicle converted to a CFV complies
with the CFV standards. Under the first option, enforcement actions would be taken solely against the
installer. Under the second option, enforcement actions could be taken against the installer or the kit
manufacturer, or both. EPA requested comment on how the term person who converts should be
defined for the purposes of determining responsibilities under CFV certification, warranty and liabiln\
provisions. The responsibilities of original equipment manufacturers for parts and operation of
converted vehicles is addressed in a later section
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
Summary of Comments
Following is a summary of representative comments on the two options proposed regarding
the definition of "person who converts" in Section 247(c) for the purposes of determining warranty
and liability responsibilities. In its comments on the NPRM, the National Association of Fleet
Administrators voiced concerns over the reported poor emissions performance of some present day
converted vehicles and encouraged EPA to promulgate strict warranty provisions and standards of
liability such as those enacted by the California Air Resources Board in its regulation of alternative
fuel retrofit systems." Cummins recommended the adoption of the second proposed option that would
require conversion kit manufacturers and installers to use certified hardware and to accept m-use
liability for warranty and recall. Cummins also noted that the kit manufacturer is in the best position
to perform the prescribed certification testing. The Natural Gas Vehicle Coalition (NGVC) and the
American Gas Association (AGA) commented that the conversion kit manufacturer should be
responsible for kit certification, and for in-use emission performance of kit hardware except where
performance failures result from poor installation. NGVC and AGA also stated that installers should
be responsible for installing properly-certified kits in conformance with the kit manufacturer's
instructions.
Analysis and Response to Comments
EPA is establishing a system for defining the responsibilities of the various parties involved in
converting a vehicle to a CFV that is an outgrowth and synthesis of the two options discussed above.
Following is a discussion of the significant advantages and disadvantages inherent in each of the
proposed options, a discussion of pertinent public comment, and the recommended approach.
A significant advantage inherent in the first option is that liability is easily assigned and
enforcement is less complicated if a single entity is held accountable for warranting each vehicle's
emissions performance and is subject to production line testing requirements. The existence of such a
sole liable party may also simplify the task of purchasers of converted vehicles seeking redress for
emissions performance failures under warranty provisions.
A disadvantage in this option is that the installer may not be the appropriate party on which to
focus all responsibility Several commenters indicated that the kit manufacturer is in the best position
to perform the prescribed certification testing. Also, since there are currently a large number of
installers m relation to the number of kit manufacturers, the number of certifiers would likely be larger
under the first option than if the kit manufacturer were allowed to certify a conversion configuration
directly. This would likely result in a greater number of certifications for the same conversion
configuration and may tend to increase the number of parties agamst which enforcement and warranty
actions would need to be taken. The existence of such a large number of certifier-installers and the
11 Sections 2030 and 2031 of Title 13, California Code of Regulations.
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
fact that many installers are relatively small businesses with limited financial resources12 may
adversely affect the confidence of the purchasers of converted vehicles in their ability to pursue
warranty claims. As discussed above, the need for strong warranty and recall provisions to improve
confidence of purchasers of converted vehicles was noted in the public comment on the NPRM.
The second option offers the advantage of allowing EPA to hold kit manufacturers legally
responsible for some or all of the certification, production line testing, in-use testing, warranty, and
recall requirements. Given the large number of installers in relation to the number of kit
manufacturers, it will be more practical to focus enforcement efforts on kit manufacturers. This option
would also allow EPA to distribute the responsibility for certification, and warranty and recall between
a kit manufacturer and installers in a manner consistent with their abilities and level of involvement in
the conversion process. As noted above, public comment was generally in support of adopting this
option.
A significant disadvantage in this approach is that factual disputes between the parties
regarding the actual cause of the emission failure could become a complicating factor during an
enforcement action. This could lead to lengthy proceedings between the involved parties which in turn
may delay resolution of emission problems and/or the compensation to vehicle owners for in-use
performance problems covered under vehicle warranty.
In the final rule, the "person who converts" for the purposes of section 247(c) is defined as
follows. Any entity (kit manufacturer, installer, or other) can apply for certification of a conversion
configuration and receive a federal certificate of conformity. This certifier will be considered the
"person who converts" under section 247(c) and will assume all responsibility as the manufacturer
under sections 206 and 207. EPA believes that this approach is a reasonable interpretation of the term
"person who converts" in section 247(c) since the certifier is the key party in arranging for the
conversion to take place. This approach synthesizes the two proposed options in a way that responds
to key comments and avoids the major drawbacks of the proposed options.
Under this approach a single party will be responsible for warranting the vehicle's emissions
performance, and liability could easily be identified for enforcement and warranty purposes as under
the first option considered in the NPRM. In addition, this approach avoids the disadvantages inherent
in the first option by providing industry with the flexibility to determine which business entity is in the
best position to provide EPA with the data necessary for certification and to assume responsibilities as
the manufactuier. Based on public comment, EPA anticipates that m most cases the kit manufacturer
will be the certifying party. Since the certifier assumes liability for in-use vehicle performance failures
that result from faulty installations, EPA expects that the certifier will develop oversight programs to
ensure that installations are performed properly and will enter into indemnification agreements with
installers.
Thus, the result of holding the certifier solely lesponsible is consistent with the intent of the
12 U.S. Environmental Protection Agency, Office of Mobile Sources, "A Preliminary Assessmeni > i
the Gaseous Fuels Aftermarket Conversions Industry, EPA Contract 68-C1-0059, September 28, 19^2
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second option and with public comment m that it distributes in an equitable manner the responsibility
for certification, and warranty and recall among all those responsible for the completion of the final
vehicle. Given that under the second option, kit manufacturers would have been liable for any
violation, this approach does not substantially increase manufacturers' liability. In addition,
enforcement actions by EPA will be simplified and the resolution of warranty claims by vehicle
owners will be expedited. EPA believes that this approach best satisfies the need expressed in public
comment to provide strict standards of liability m order to instill consumer confidence in the emissions
performance of converted vehicles. Holding the certifier solely responsible is also consistent with the
approach taken in the Gaseous Fuels Final Rule and with other EPA vehicle certification programs.
B. Liability of the Original Equipment Manufacturer
Summary of Issue
In the NPRM, EPA proposed that the original equipment manufacturers (OEMs) would remain
responsible for warranting vehicle parts and operation existing in the vehicle pnor to conversion and
not affected by the conversion.
Summary of Comments
Public comment was mixed on the issue of OEM liability. Cummins stated that since the
OEM has no control over the impact that the vehicle conversion will have on the performance and life
of the original parts that the OEM's warranty liability should end at the time of conversion. The
Engine Manufacturer's Association stated that the OEM should only be liable for emission failures that
are directly traceable to the OEM and should not be liable for failures resulting from conversions or
specifically from parts that were used for the conversion but were not manufactured by the OEM. The
Natural Gas Vehicle Coalition and the American Gas Association stated that the OEM should continue
to be responsible for the performance of the emissions control equipment that was on the vehicle
before it was converted unless it is shown that the conversion caused the failure of this equipment.
Analysis and Response to Comments
EPA recommends that the OEM remain responsible for the equipment that was on the vehicle
before it was converted unless the conversion caused the failure of the OEM equipment to function in
its role in meeting emission standards. EPA believes that this approach is necessary to ensure that
converted vehicles comply with the CFV standards because the proper performance of the conversion
configuration relies on the OEM's underlying emissions control systems. Also, EPA interprets section
247(c) of the CAA to direct that a CFV aftermarket conversion certifier will not be required to warrant
any vehicle for parts or Operation existing in the vehicle prior to conversion and not affected by the
conversion.
It appears necessary to determine whether m-use enforcement actions should be brought
against an OEM or a converter on a case by case basis since it is not feasible to codify guidelines bs
which a decision regarding such liability should be made It is possible that the converter, the OEM
or both, could be liable for a converted vehicle's in-use noncompliance with applicable emissions
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Clean Fuel Fleet and California Pilot Program
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standards depending on the cause of the particular problem. EPA is aware that there may be cases
where the conversion is responsible for the ui-use noncompliance of the vehicle on its original fuel,
even though the conversion did not directly affect the performance of any OEM components. For
example, if the OEM vehicle were certified with a compliance margin which would have allowed for
some increase of in-use emissions, and the extra weight of the conversion hardware and fuel tanks
reduced that margin to the pomt where in-use noncompliance on the original fuel began to occur, the
conversion certifier would be liable. As another example, if a dual-fuel vehicle experiences in-use
emissions problems on the original fuel, the OEM would be held liable if EPA determines that the
problem was caused by a problem with the OEM equipment, such as catalyst failure. However, the
liability would be the converter would be liable if EPA were to determine that the catalyst failure was
caused by use of the new fuel. One indicator that might be useful in determining that the OEM was
liable for an emission failure of a converted vehicle would be an emission related recall action against
unconverted OEM vehicles of the same model.
C. Definition of a Converted Vehicle's Useful Life
Summary of Issue
The CAA does not specify whether the useful life period of converted vehicles for the
purposes of in-use liability should be measured from the time of original vehicle manufacture, or from
the time of conversion. EPA requested comment on this issue.
Summary of Comments
All of the public comment received suggested that the liability of the converter should not
extend beyond the original useful life of the vehicle. In their comments, the Natural Gas Vehicle
Coalition and the American Gas Association noted that it would be inappropriate to extend liability for
in-use emissions performance beyond the original useful life of the vehicle since the performance of
the aftermarket conversion system depends on the OEM's underlying emissions control system, which
is only warranted for the useful life of the original vehicle.
Analysis and Response to Comments
EPA agrees with the public comment on this issue and is limiting the liability of both the
OEM and converter for in-use emission performance to the original vehicle/engine's useful life.
Defining useful life in this way creates the potential situation where CFV purchase requirements could
be satisfied by converting vehicles that have little mileage remaining in their useful life. If this were
to occur to a significant degree, it is possible thai CFF purchase requirements could be met but few
emissions reductions would be realized. However. EPA believes that financial disincentives involved
with converting such vehicles solely to meet CFF purchase requirements and with maintaining vehicles
past their useful life will make such a situation unlikcK Hence it is not a significant concern
O. Post-Installation Quality Test
Summary of Issue
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
CFV emission standards are considerably more stringent than conventional standards, and
converted vehicles that are certified as CFVs and purchased by fleet operators to meet the
requirements of the fleet program will be eligible to earn marketable purchase and emission credits and
receive TCM exempUons as CFV's (LEVs, ULEVs, ZEVs or ELEVs). In the NPRM EPA requested
comment on whether additional requirements are necessary to ensure that converted vehicles comply
with these standards given that the conversion industry historically has consisted of a large number of
relatively small businesses that have not previously faced specific emissions performance requirements.
Specifically, EPA requested comment on whether it would be useful to require a post-installation test
for vehicles converted to CFVs to assess the quality of the conversion installation from an emissions
perspective. Such a test is required by the California Air Resources Board in its regulation of
alternative fuel retrofit systems.13
EPA sought comment on one possible approach where two options would be available to
satisfy a post installation test requirement. Under the first option, the exhaust CO concentration of the
converted vehicle could be tested at a local inspection and maintenance station and would be required
to pass the cut-point for the area. Under the second option, a CO exhaust emissions idle test would be
performed at the time of certification to establish a reference value against which the post-installation
test results of converted vehicles would be compared. The certifier could then perform post-
installation tests on its converted vehicles using the same idle test procedure and the CO emissions
would be required to be within 20 percent of the value measured during certification. In the NPRM,
EPA stated that such a post-installation test requirement would be most useful in identifying gross
installaUon errors and would provide some additional level of assurance that CFV standards are being
met.
Summary of Comments
Of those commenting on this subject, all expressed concern regarding reports of poor
emissions performance of some converted vehicles presently in use and staled that EPA should
promulgate strict standards to instill consumer confidence in the emissions performance of vehicles
converted to CFVs. Sun stated that to assess the quality of the conversion each vehicle should be
tested prior to release to the consumer. The NGVC and AGA expressed support for the EPA concept
of a post-installation test of CO emissions to help identify poor installations or defective conversion kit
hardware that would otherwise result in high emissions. NGVC and AGA also stated that such a test
would help to identify poor installations that could cause m-use noncompliance with the CFV emission
standards and that the testing option that employs an idle test performed by the manufacturer should
not pose a significant burden since most CFV aftermarket conversion certifiers should have at least
one four-gas analyzer.
However, NGVC and AGA also stated that since many gaseous fueled vehicles have extremely
low idle CO emissions, it would be inappropriate to require each individual conversion to match the
percent of CO from the certification vehicle within 20 percent As an alternative, these commenters
stated that EPA should require that the CO from the converted vehicles match that of the certification
13 Title 13, California Code of Regulations. Sections 2030 and 2031.
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Clean Fuel Fleet and California Pilot Program
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vehicle within +/- 0.4 percent CO by volume or 20 percent of the CO reading, whichever is greater.
Analysis and Response to Comments
EPA is requiring vehicles converted to CFVs to undergo a post-installation test. CFV
aftermarket conversion certifiers producing 10,000 or more converted vehicles per year will not be
required to test those vehicles. EPA believes that an appropriate certification program, along with
warranty and liability provisions, will provide a sufficient degree of confidence that the in-use
emissions performance of the majority of vehicles converted to CFVs will remain in compliance with
the applicable standards. EPA believes that these provisions, coupled with production line and in-use
testing programs, wdl adequately ensure that installations by larger CFV conversion certifiers (i.e.,
those that produce or sell more than 10,000 converted vehicles per year) will be performed properly
and that the in-use emissions performance of these vehicles will comply with applicable standards.
Furthermore, EPA believes that a post-installation test for small-volume conversion certifiers is
appropriate. In comparison to large volume certifiers, there is a greater uncertainty that all smaller
conversion certifiers will have the resources and experience to institute the necessary quality control
measures.anticipated difficulty in conducting production line emissions testing at small certifiers'
facilities. In such cases, small production volumes will make the necessary statistical sampling
difficult to achieve, and such manufacturers will not generally have on-site test equipment capable of
running FTP testing. Due to these difficulties, EPA wdl not be able to rely on production line testing
of small certifiers to the same degree as it will for larger volume certifiers. Requiring post-installation
testing of CFV conversion certifiers qualifying as small-volume manufacturers would help to
compensate for this limitation. Therefore, EPA will require each vehicle converted by a CFV
aftermarket conversion certifier that sells or produces less than 10,000 converted vehicles per year to
undergo a post-installation test to assess the quality of the installation from an emissions perspective
before it may be sold as a CFV or is eligible for special benefits available to CFVs under the CFF
program.14
EPA is providing two options similar to those that were discussed in the proposal to satisfy the
post-installation test requirement. Under both options, a separate test is required for dual-fuel vehicles
for each fuel on which the converted vehicle is capable of operatmg.
Under the first option, a CO emissions test could be performed using the same equipment,
procedure, and pass/fail criteria as that used under the inspection and maintenance testing program in
the area where the testing is conducted. This test could be performed at an official inspection and
maintenance facility, by the certifier, or by the certifier's contractor. If pass/fail criteria specific to the
converted vehicle's operation on clean alternative fuel are not available, it would be appropriate to use
14 These special benefits include potential eligibiln> lor a purchase credit in the fleet program and
exemptions from some transportation control measures (TCMs) Converted vehicles could also potennalh
qualify as Inherently Low-Emissions Vehicles (LLEVsi under the program promulgated in March 1. 199^
(58 FR 11888), and receive expanded TCM exemptions Finally, converted vehicles could generate mass
emission credits for trading under state programs developed as part of the Federal Economic Incentives
Program under the Clean Air Act (58 FR 11110, February 23, 1993).

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Clean Fuel Fleet and California Pilot Program
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the pass/fail criteria applicable to the vehicle's operation on gasoline prior to conversion.
The second option was designed to accommodate cases in which inspection and maintenance
testing procedures are not available, but would be available to any CFV aftermarket conversion
certifier. In the NPRM, EPA discussed adopting a single-speed idle test per 40 CFR 85.2212 as an
alternative to the inspection and maintenance testing facilities procedure described above. Since the
publication of the NPRM, EPA has further evaluated the capabilities and limitations of potential post-
installation test procedures and has determined that measuring CO emissions on an existing two-speed
idle test13 would provide greater assurance of properly identifying gross installation errors while
limiting the potential of false failures as compared to a single-step idle test. EPA believes that the
minor change from a single-speed to a two-speed idle test will not add significantly to the cost and
difficulty of post-installation testing.16 The California Air Resources Board's regulation of alternative
fuel retrofit systems also requires that a two-speed idle test be performed as part of a post-installation
vehicle evaluation.17 For these reasons, EPA is adopting the two-speed idle test of CO emissions as
the required post-installation test when an inspection and maintenance test procedure is not available.
A two-speed idle test would be required to be performed on the certification vehicle during
certification testing to establish reference values (at idle and 2500 rpm) against which post-installation
test results would be compared. As discussed above, EPA considered requiring that each vehicle's
post-installation test CO emissions measurement be below the reference value established at the time
of certification plus 20 percent of the reference value. However, EPA agrees with the public comment
noted above that such a cut-point is impractical. The alternative cut point suggested in the public
comment of the CO certification reference value plus 0.4 percent CO by volume appears to be
appropriate.
The 0.4 percent CO cut point is very similar in stringency to the 0.5 percent CO standard
promulgated for the certification short test (CST) two-speed idle procedure for gasoline-fueled vehicles
(58 FR 58382 - 58440, November 1, 1993). The CST standard was based on a review of data
collected from inspection and maintenance facilities that employ a two-speed idle test. These data
indicate that production line gasoline powered vehicles from non-pattern failure engine families could
13 The two-speed idle test (40 CFR 85-2215 EPA 91) is described m the Short Test Emission
Regulations Final Rule, 58 FR 58405 - 58407.
16	The two-speed idle test requires a tachometer and a special multiple emission measurement
computer software algorithm that are not required for (he single-speed idle test. However, many emissions
testing facilities will already have access to such equipment and EPA believes the cost to those who m.n
need to acquire the additional equipment to be less than $300. based on EPA experience with such lot
equipment.
17	Title 13, California Code of Regulations, Sections 2030 and 2031.
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
easily meet a 0.5 percent CO standard." Since the CO emissions of CFVs can be expected to be no
greater than, and m many cases to be less than, those from vehicles meeting Tier 1 and Tier 2
standards, EPA believes that properly manufactured CFVs can also easily meet a 0.5 percent CO
standard and will therefore not have difficulty in meeting a standard of 0.4 percent plus the
certification reference value (the sum of which will likely total more than 0.5 percent in most
instances). Based on the above discussion, EPA believes that a cut point of the CO certification
reference value plus 0.4 percent CO by volume provides reasonable assurance that gross installation
errors will be discovered while sufficiently limiting the probability of false test failures, and therefore
adopts this pass/fail criteria for the two-speed idle post-installation test.
In suggesting a post-installation test requirement for vehicles converted to CFVs in the NPRM,
EPA proposed to allow certifiers that convert fewer than 300 vehicles per year special exemptions
from the post-installation test requirements when inspection and maintenance test facilities are not
available.19 EPA believes that it is unlikely that certifiers will be located in areas without access to
such facilities. However, inspection and maintenance testing is not available for heavy duty vehicles
in all areas, and the alternate two-speed idle post-installauon test recommended may represent a
burden for small manufacturers. Therefore, in cases where inspection and maintenance testing is not
available, it is recommended that certifiers which sell or produce fewer than 300 vehicles in a calendar
year may request an exemption from EPA from the post-installation test requirement. Included m the
request for exemption should be the estimated number of vehicles and engines that the certifiers will
convert in the calendar year, a description of any emissions related quality control procedures used,
and sufficient information to demonstrate that the post-installation testing requirement represents a
severe financial hardship. EPA believes that it is not appropriate to grant an automatic exemption to
such certifiers as was discussed in the NPRM because it is unlikely that the post-installation test
requirement would represent a significant burden in most cases and it is these smaller-volume certifiers
for which the greatest concerns about emissions quality exist.
E. On-Board Diagnostics
Summary of Issue
The NPRM stated that the provisions of 40 CFR part 86 would apply to CFV conversions
unless those requirements are superseded by the requirements of part 88. Since EPA did not propose
in the NPRM for this rule to supersede the on-board diagnostics (OBD) requirements in part 86, the
proposed program would apply federal OBD requirements to vehicles converted to CFVs.
Summary of Comments
18	Sierra Research Inc , "Analytical Support for Selection of Certification Short Test Standards" Repoi i
No. SR93-03-0, EPA Air Docket #A-91-21. item 1V-A-01. March 4. 1993
19	The suggested guidelines for the post installation test were placed in Secuon II-A of the publK
docket.
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
In its comments on the NPRM, the American Automobile Manufacturers Association (AAMA)
stated that EPA needs to clarify the allocation of responsibilities for ensuring that CFV conversion
configurations meet applicable OBD requirements. AAMA stated that in many cases conversion
companies lack the necessary expertise, information, and other resources to maintain OBD system
integrity. The Natural Gas Vehicle Coalition (NGVC) expressed concerns about the impact on the
conversion industry of satisfying OBD requirements. A delay in the imposition of OBD requirements
from 1994 to 1996 to provide additional time for engineering of OBD for conversions was requested.
The NGVC noted that the OBD system must be adapted to account for NMHC rather than THC
emissions and that a small increase in THC emissions, even if the emissions consisted only of
methane, could cause a natural gas vehicle to be in violation of OBD rule. The NGVC also requested
that original equipment manufacturers be required to provide to converters the information necessary
to design conversion systems which will not trigger the OBD system when emissions have not in fact
increased.
Analysis and Response to Comments
Section 242(b) of the Act requires light-duty CFVs to comply with all requirements of Title II
of the Act which are applicable to conventional vehicles of the same category and model year, except
to the extent that such requirements conflict with CAA Part C (i.e., clean-fuel vehicle) requirements.
Section 247(a) states that fleet operators can meet the purchase requirements of the CFF program by
converting new or existing vehicles to clean-fuel vehicles. The Act defines a clean-fuel vehicle as a
vehicle that is certified to the applicable clean-fuel vehicle standards. Therefore, a vehicle converted
to a CFV must be a certified as meeting the CFV standards, which includes demonstrating compliance
with federal OBD requirements. Thus, OBD requirements, as well as other requirements not
superseded by Part 88 regulations, will apply to vehicles converted to CFVs, including the effective
dates of the OBD regulations.
The responsibility of original equipment manufacturers to provide information related to OBD
systems to converters will be addressed in EPA's Service Information Availability Rulemaking that
will be promulgated in response to the requirements of section 202(m)(5) and therefore will not be
addressed in the context of this rulemaking.
F. Applicability of the Small Volume Manufacturers Certification Program to Conversions
Summary of Issue
In the NPRM, EPA proposed that the Small Volume Manufacturers (SVM) Certification
Program (40 CFR 86.092-14) apply to CFV aftermarket conversion certifiers. EPA proposed that the
program be available to all certifiers regardless of the number of vehicles that were converted within a
given calendar year. The Agency also proposed thai (he same provisions for demonstrating the
durability of emissions applicable to the current SVM Certification Program apply to CFV conversion
configurations as well.
Summary of Comments
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
The comments received on the issue where supportive of allowing all aftermarket conversion
certifiers to certify under the Small Volume Manufacturer Certification rules. Comments were also
received that the CFV regulation should be as consistent as possible with other EPA regulations and
the regulation on aftermarket conversions enacted in the State of California.
Regarding durability demonstration, the Natural Gas Vehicle Coalition (NGVC) and the
American Gas Association (AGA) urged EPA to make the requirements for conversion system
durability demonstration under the Small Volume Certification Program as consistent as possible with
the requirements under the California regulation of aftermarket conversions. In particular, it was stated
that EPA should accept as proven technology under the SVM program any aftermarket conversion
technology that has been durability tested and certified under the California's bench test procedures or
by in-use testing. The NGVC and AGA stated that the existence of different requirements would lead
to duplication, and may place an excessive burden on conversion system manufacturers.
Analysis and Response to Comments
EPA will apply the provisions of the SVM Certification program in their entirety to CFV
conversions. EPA agrees with commenters' concerns regarding consistency with the Gaseous Fuels
final rule, and believes that a single program that applies to all federal vehicle certifications, mcluding
certifications of CFV conversion configurations and other conversion configurations, represents the
best policy. Since the Gaseous Fuels final rule applies the SVM volume limit (10,000 vehicles) and
the SVM durability demonslrauon requirements to conversion configurations in general, EPA believes
that it is important to follow that same policy for CFV conversions. Thus, when the SVM program is
used by a CFV aftermarket conversion certifier, the volume limit and the durability demonstration of
the existmg SVM certification program will apply (40 CFR 86.092-14).
EPA did not in this rulemaking propose a sales or production volume limit for CFV
aftermarket conversion certifiers wishing to use the SVM Certification program, nor did EPA receive
any comments on this issue in this rulemaking. As discussed in the preamble to the rule, EPA is
implementing this requirement as a direct final rule and allowing the appropriate opportunity for public
comment on this issue before finalizing the sales volume limit for certification of CFV conversion
configurations under the SVM Certification program.
G. Vehicle Safety
Summary of Issue and Comments
In its comments on the NPRM the Electric Transportation Coalition stated that EPA
regulations should focus only on those issues that deal with the emissions impacts of converted
vehicles and that the assessment of safety and warranty issues related to vehicle safety should be left
to another forum.
Analysis and Response to Comments
Section 247(e) directs the Department of Transportation (DOT) to promulgate safety regulation
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
for CFV conversion configurations if necessary. Olher than findings and requirements under sections
202(a)(4) and 206(a)(3)(A) and (B), issues related to vehicle safety are typically not addressed by EPA
in its regulations dealing with vehicle emissions but rather are addressed by DOT. This is the case for
this rulemaking.
H.	Purchase Requirements
Summary of Issue and Comments
NAFA expressed a concern that EPA's proposed regulations do not address the specific
statutory provision that fleet operators are not required to perform aftermarket conversions to existing
or new vehicles under the CFF program. NAFA states that this is an important issue that had not been
addressed by EPA in SIP guidance.
Analysis and Response to Comments
EPA believes that the statute is clear in prohibiting states from implementing fleet purchase
requirements under the CFF program that require fleet operators to purchase converted vehicles, or to
convert existing vehicles to CFVs. The language of section 247(a) is sufficient, and does not require
action by EPA on this point. Therefore, EPA will not independently address this issue in the final
rule.
I.	Suggestions for Special Treatment of Conversions for Testing and Certification
Summary of Issue and Comments
NAFA and NGVC/AGA made several suggestions relating to how certification and testmg
should be done for conversions. Included were suggestions that CARB conversion certification
provisions be adopted and that testing of conversion configurations for CARB be accepted by EPA.
NGVC/AGA also suggested that EPA allow chassis (whole-vehicle) testing in place of engine testing
for CFV conversions of heavy duty vehicles/engine up to 14,000 pounds GVWR. NGVC/AGA also
requested additional leadtime before the conversion provision would become effective to allow time
for the aftermarket conversion industry to develop further.
Analysis and Response to Comments
Because the CAA requires that entities which convert vehicles to CFVs be treated as
manufacturers for certain purposes, EPA believes that such entities should to the greatest extent
possible be covered by the same testmg and certification requirements which apply to manufacturers of
other CFVs. In addition, section 247(b) of the Act provides that EPA regulations governing
conversions of vehicles to CFVs shall apply to such conversions the same requirements of Title II that
apply to all CFVs, except where modifications are necessary for CFV conversion configurations
(Only in the case of the post-installation test does EPA believe that special consideration for CFV
conversion configurations is useful.) While in some cases this approach will result in slight variations
from CARB's treatment of conversions, EPA believes that the value of a common set of requirements
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
for all CFV certifications outweighs the benefit of duplicating CARB rules for converted vehicles.
This approach also will achieve a high degree of consistency between the provisions for CFV
conversions in this rule and the general provisions for all conversions in the Gaseous Fuels final rule.
It was suggested by NGVC-AGA that EPA allow the use of chassis-test data for CFV
conversions on HDVs/engines up to and including 14,000 lbs. GVWR. The Agency is currently
considering two requests for waiver of federal preemption for chassis standards applicable to vehicles
of 8,500 to 14,000 lbs. GVWR (California's medium-duty vehicle category). In the past EPA
determined that the chassis test, which is speed dependent, was inappropriate for HDVs above 10,000
lbs. GVWR, whose loads can vary widely, and would therefore more appropriately be represented by
the load dependent engine test EPA has in the past been willing to accept alternative types of data as
long as the Agency was assured that the data demonstrated compliance with EPA requirements.
However, it remains to be seen whether a manufacturer would be able to demonstrate compliance to
the federal engine-based standards with chassis-based test data for any or all applicable fuel types.
(Those interested should consult EPA Air Dockets A-91-55 and A-91-71.) Thus, until such time as
the Agency is convinced that chassis-based data is capable of demonstrating compliance with engine-
based federal standards the Agency will not accept such data for HD CFV conversion configurations.
If however, EPA develops or becomes aware of new data or changed circumstances which indicate
that a policy change is appropriate, EPA reserves the right to reconsider this policy.
In response to the comment requesting a delay in the effective date of the CFV conversion
rules, EPA notes that nothing in the regulations mandates the use or production of CFV conversion
configurations. However, some entities are likely to be able to certify CFV conversion configurations
in the early years of the CFF program, and EPA believes that these entities should be subject to full
certification requirements for CFV conversion configurations. EPA believes that it would be damaging
to the fleet program and to the credibility of the conversions industry if a separate class of CFVs
subject to less rigorous emission requirements (i.e. CFV conversion configurations that were certified
in the early years of the program under NGVC's suggested approach) were allowed to participate m
the CFF program.
IV. California Pilot Test Program
A.	Clean-Fuel Vehicle Standards
EPA received several comments regarding the CFV emission standards, which are applicable
to both the Clean Fuel Fleet program and the Pilot program. EPA's response to those comments are
covered in part II, Clean-Fuel Vehicles, above
B.	Treatment of Small Volume Manufacturers
Summary of Issue
EPA proposed that, for the California Pilot Program, "small volume manufacturer" be defined
as one which had California sales of light-duty vehicles and light-duty trucks of less than 3,000
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Clean Fuel Fleet and California Pilot Program
Summary dt Analysis of Comments
vehicles in the previous model year. EPA also proposed to delay compliance with the sales
requirements of the Pilot program until model year 2001 for these manufacturers.
Summary of Comments
Rover Group commented that, under the proposal, small volume manufacturers would have to
rely on the Pilot program credit program if they did not meet the 3,000 threshold and had only one
year to prepare for production of their required number of clean-fuel vehicles. Rover Group also
stated that such manufacturers should not have to comply with Pilot program requirements until they
are required to produce LEVs in California. They believe that reliance on the credit program during
the early years of the Pilot program is not practical or feasible because of 1) the lack of assurance that
credits will even be available and 2) if they are available, the affordability of such credits. According
to Rover Group, taking a chance with credits and/or fines could result in financial ruin. On the other
hand, attempting to meet sales requirements could necessitate that small volume manufacturers commit
to the technology early at a great development cost relative to their sales volume. Small volume
manufacturers may have to stay out of the U.S. market until credit issues become clearer.
Both the Association of International Automobile Manufacturers and Rover Group called for
more consistency between CARB's definition and that which EPA has proposed. They both want
EPA to define "small volume manufacturer" as the "rolling average" of three model years with sales
less than 3000 units. Manufacturers exceeding the 3000 unit threshold would be provided the normal
four years leadtime before being required to produce the required percentage of LEVs. Rover Group
added that, since this program will be implemented in California, only California sales should be taken
into consideration.
Analysis of Comments
Taking into consideration the above comments, EPA agrees that a goal in developing the Final
Rule for the Clean Fuel Fleets Program and the California Pilot Program is to provide as much
consistency with California LEV program provisions and requirements as possible while at the same
time establishing sound EPA policy and satisfying the objectives of the Clean Air Act EPA believes
that the proposed approach can be modified to accomplish these goals.
EPA proposed that, for purposes of the Pilot program, the distinction between small and "non-
small" volume manufacturers would disappear in model year 2001 and thereafter. Because of this and
the fact that the CARB LEV Program maintains the small volume manufacturer distinction
indefinitely, the CARB leadtime of four years for small manufacturers who no longer qualify as
"small" is not practical since small volume manufacturers only exist for the first five years of the Pilot
program. EPA also believes that it is necessary for leadtime considerations to establish that a
manufacturer who initially qualifies as "small" but at a later point prior to model year 2001 exceeds
the 3,000 threshold would remam "small" until model year 2001 As was proposed, EPA believes thai
small manufacturers should be given this five year delay before they are required to satisfy their sales
share; to do otherwise would be unnecessarily complicated
Response to Comments
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dean Fuel Fteei and California Pilot Program
Summary <6 Analysis of Comments
For purposes of the Pilot program, EPA is defining "small volume manufacturer" to be as
consistent with CARB's definition as practicable, A small volume manufacturer, for purposes of the
Pilot program, is one with average annual LDV and LDT sales in California of less than or equal to
3,000 units during a consecutive three-year period beginning no earlier than 1993. Manufacturers with
less than three consecutive years of sales in California should be able to use either one year of sales
or, if available, an average of two years of sales in California. A manufacturer certifying for the first
time in California will be considered small if its projected average annual California sales are at or
below 3,000 vehicles. Actual sales data should be used in subsequent model years. A manufacturer
which does not qualify as small in model year 1996 but does qualify as small before model year 2001
should be treated as a small volume manufacturer beginning with the first model year after which it
qualifies as "small" up until model year 2001. EPA will also grant leadtime to small volume
manufacturers who exceed the average annual level before requiring them to meet the Pilot program
requirements, which is consistent with CARB's approach. If a manufacturer qualifies as "small" at
any time prior to model year 2001, the manufacturer should not have to meet a calculated sales share
requirement until model year 2001. These provisions are all very similar to those of CARB while
responding to the special characteristics of the Pilot Program. EPA is requiring that, as proposed,
beginning with model year 2001, all manufacturers regardless of average annual sales be required to
meet their calculated CFV sales share.
V. Regulatory Impacts
A. Program Costs
Summary of Issue and Comments
A number of commenters suggested thai EPA's projected incremental acquisition and
operating casts for CFVs were too low, Several commenters argued that infrastructure costs for
alternative fuels can Ise significant and should be included in Hie regulatory impacts analysis.
In addition, Mobil Oil commented that EPA has proposed a scenario which assumed
automobile manufacturers (OEMs) will provide more non-petroleum fuel/vehicle combinations
(Scenario II in proposed RIA for this rulemaking), and that it is inappropriate for clean-fuel vehicle
regulations to make assumptions that are not fuel neutral since the clean-fuel vehicle programs are
fuel-neutral.
Analysis and Response to Comments
EPA believes that the projected incremental acquisition and operating costs used in the
proposal are appropriate. As described m the Regulatory Impact Analysis for this rule (found in
docket for this rule), EPA reconsidered the proposed cost projections of the CFF program with the best
information available and concludes that no changes to (he cost projections are necessary since the
proposed costs remain reasonable. EPA also considered adding infrastructure costs to the analysis, but
concluded that too little information exists in this area ,md that it was not central to the issue of clean-
fuel vehicle emission standards or conversions since the use of a specific fuel is not mandated.
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Clean Fuel Fleet and California Pilot Program
Summary & Analysis of Comments
EPA disagrees with Mobil Oil's comment that EPA assumptions made in the RIA are not fuel
neutral. The Agency analyzed five different types of fuels (alcohol fuels, CNG, LPG, electricity, and
reformulated gasoline) in its assessment of future fleet use of fuels. Furthermore, EPA believes that
both scenarios of fleet fuel usage presented in the RIA are reasonable estimates of the future use of
fuels by fleets in the CFF program. For Scenario I and n, EPA projected that vehicles operating on
reformulated gasoline vehicles would make up 70 and 50 percent of the CFV population, respectively.
B. Additional Program Impacts
Summary nf issue and Comments
A number of commenters argued that when determining the cost of petroleum displacement
by alternative fuels, lost tax revenues by all levels of government must be considered if the alternative
fuel is taxed at a lower rate on an energy-equivalent basis. They stated that whether the taxes on
alternative fuels must be included in the cost section or the loss of taxes must be included in the
additional program costs section, ignoring taxes depicts an extremely optimistic economic outlook that
can have deleterious effects on the American economy. Dependent on state tax treatment, each state
could stand to lose millions of dollars in revenue.
Analysis and Response to Comments
EPA believes it would be inappropriate to attempt to account for lost tax revenues to
government entities due to petroleum displacement since there is no guarantee that government tax
policies will remain the same, and thus, it is extremely difficult to project the impact of such taxes
under the CFF program. Furthermore, the impact of lost tax revenues from petroleum displacement
caused by the CFF program is likely to be insignificant since such displacement will be minimal due
to the fact that the program is fuel neutral and not an alternative fuel mandate . Therefore, EPA
believes it is inappropriate to consider projected lost tax revenues in the economic analysis for this
rule.
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