[Federal Register: May 26, 2010 (Volume 75, Number 101)]
[Proposed Rules]
[Page 29605-29645]
[DOCID:fr26my10-20]

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Part II

Environmental Protection Agency

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40 CFR Parts 85 and 86

Clean Alternative Fuel Vehicle and Engine Conversions; Proposed Rule

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 85 and 86

[EPA-HQ-OAR-2009-0299; FRL-9149-9]
RIN 2060-AP64

Clean Alternative Fuel Vehicle and Engine Conversions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to simplify and streamline the process by
which manufacturers of clean alternative fuel conversion systems may
demonstrate compliance with vehicle and engine emissions requirements.
Specifically, EPA is proposing to revise the regulatory criteria for
gaining an exemption from the Clean Air Act prohibition against
tampering for the conversion of vehicles and engines to operate on a
clean alternative fuel. Under existing EPA regulations, an exemption
from the tampering prohibition may only be granted to vehicles and
engines covered by a certificate of conformity. The proposed revisions
would create additional compliance options beyond certification that
would protect manufacturers of clean alternative fuel conversion
systems against a tampering violation, depending on the age of the
vehicle or engine to be converted. The new options would alleviate some
economic and procedural impediments to clean alternative fuel
conversions while maintaining environmental safeguards to ensure that
acceptable emission levels from converted vehicles are sustained.

DATES: Comments must be received on or before July 23, 2010. Under the
Paperwork Reduction Act, comments on the information collection
provisions are best assured of having full effect if the Office of
Management and Budget (OMB) receives a copy of your comments on or
before June 25, 2010.
    Public Hearing: EPA has tentatively scheduled a public hearing
about this proposal for 9 a.m. June 23, 2010. EPA will hold the hearing
only if any party notifies EPA by June 18, 2010 of interest in
presenting oral testimony at the hearing. The hearing will start at 9
a.m. local time and continue until everyone has had a chance to speak.
    EPA will cancel the hearing if no one expresses interest by June
18, 2010. EPA will notify the public of a cancellation by publication
in the Federal Register, via its alternative fuel conversion Web site,
http://www.epa.gov/otaq/consumer/fuels/altfuels/altfuels.htm and via
Enviroflash.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2009-0299 by one of the following methods:
     http://www.regulations.gov: Follow the online instructions
for submitting comments.
     Mail: Environmental Protection Agency, EPA Docket Center
(EPA/DC), Air and Radiation Docket, Mail Code 2822T, 1200 Pennsylvania
Avenue, NW., Washington, DC 20460, Attention Docket ID No. EPA-HQ-OAR-
2009-0299. In addition, please mail a copy of your comments on the
information collection provisions to the Office of Information and
Regulatory Affairs, Office of Management and Budget (OMB), Attn: Desk
Officer for EPA, 725 17th St., NW., Washington, DC 20503.
     Hand Delivery: Docket Center, (EPA/DC) EPA West, Room
B102, 1301 Constitution Ave., NW., Washington, DC, Attention Docket ID
No. EPA-HQ-OAR-2009-0299. Such deliveries are only accepted during the
Docket's normal hours of operation, and special arrangements should be
made for deliveries of boxed information.
    Public Hearing: The June 23, 2010 hearing will be held at the EPA
National Vehicle and Fuel Emissions Laboratory, 2000 Traverwood Drive,
Ann Arbor, Michigan 48105. The hearing will start at 9 a.m. local time
and continue until everyone has had a chance to speak. See the
Supplementary Information for more information on the public hearing.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2009-0299. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through http://
www.regulations.gov or e-mail. The http://www.regulations.gov Web site
is an ``anonymous access'' system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through http://www.regulations.gov your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses. For additional information about EPA's public
docket visit the EPA Docket Center homepage at http://www.epa.gov/
epahome/dockets.htm.
    Docket: All documents in the docket are listed in the http://
www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the following
location: EPA Docket Center, EPA/DC, EPA West, Room 3334, 1301
Constitution Ave., NW., Washington, DC. The Public Reading Room is open
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal
holidays. The telephone number for the Public Reading Room is (202)
566-1744.

FOR FURTHER INFORMATION CONTACT: Amy Bunker, Compliance and Innovative
Strategies Division, U.S. Environmental Protection Agency, 2000
Traverwood Drive, Ann Arbor, Michigan 48105. Telephone:<PHONE_NUMBER>.
E-mail Address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Public Hearing

    Anyone wishing to present testimony about this proposal at the
public hearing should notify the general contact person (see FOR
FURTHER INFORMATION CONTACT) no later than five days prior to the day
of the hearing. The contact person should be given an estimate of the
time required for the presentation of testimony and notification of any
need for audio/visual equipment. Testimony will be scheduled on a first
come, first serve basis. A sign-up sheet will be available at the
registration table the morning of the hearing for scheduling those who
have not notified the contact earlier. This testimony will be scheduled
on a first come, first serve basis to follow the previously scheduled
testimony.

    EPA requests that approximately 50 copies of the statement or
material to be presented be brought to the hearing for distribution to
the audience. In addition, EPA would find it helpful to receive an
advance copy of any statement or material to be presented at the
hearing at least one week before the scheduled hearing date. This is to
give EPA staff adequate time to review such material before the
hearing. Such advance copies should be submitted to the contact person
listed.
    The official record of the hearing will be kept open for 30 days
following the hearing to allow submission of rebuttal and supplementary
testimony. All such submissions should be directed to Docket No EPA-HQ-
OAR-2009-0299 (see ADDRESSES). The hearing will be conducted
informally, and technical rules of evidence will not apply. A written
transcript of the hearing will be placed in the above docket. Anyone
desiring to purchase a copy of the transcript should make individual
arrangements with the court reporter recording the proceedings.

Affected Entities

    This action will affect companies and persons that manufacture,
sell, or install alternative fuel conversions for light-duty vehicles,
light-duty trucks, medium-duty passenger vehicles, and heavy-duty
vehicles and engines. Such entities are categorized as follows:

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                                   Examples of potentially regulated
       NAICS Codes \1\                          entities
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335312.......................  Motor and Generator Manufacturing.
336312.......................  Gasoline Engine and Engine Parts
                                Manufacturing.
336322.......................  Other Motor Vehicle Electrical and
                                Electronic Equipment Manufacturing.
336399.......................  All Other Motor Vehicle Parts
                                Manufacturing.
811198.......................  All Other Automotive Repair and
                                Maintenance.
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    This list is not intended to be exhaustive, but rather to provide a
guide regarding entities likely to be affected by this action. To
determine whether particular activities may be affected by this action,
you should carefully examine the regulations. You may direct questions
regarding the applicability of this action to the contact as noted
above in FOR FURTHER INFORMATION CONTACT.
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    \1\ North American Industry Classification System (NAICS).
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Table of Contents

I. Introduction
II. Authority
    A. Vehicle and Engine Standards and Certification
    B. Useful Life
    C. ``Tampering'' Prohibition
    D. Exemption for Conversions
    E. Authority for Proposed Clean Alternative Fuel Conversions
Program
III. Program Design Elements Applicable to All Clean Alternative
Fuel Conversions
    A. Clean Alternative Fuel Conversions
    B. Good Engineering Judgment
    C. Vehicle/Engine Groupings and Emission Data Vehicle/Engine
Selection
    D. Flex-Fuel (Bi-Fuel) and Dual Fuel Conversions
    E. Vehicle and Packaging Labels
    F. Marketing
    G. Compliance
    1. Emission Standards
    a. Light-Duty and Heavy-Duty Complete Vehicle Gross Vehicle
Weight Classes and Alternative Fuel Exceptions
    b. Heavy-Duty Engine Types and Gross Vehicle Weight Classes
    c. Dual-Fuel Standards
    2. Useful Life
    3. On Board Diagnostics
    4. Durability Testing
    5. Warranty
    6. Other Provisions Applicable to Conversion Manufacturers
    7. Misapplication
    H. Regulatory Procedures for Small Volume Manufacturers and
Small Volume Test Groups
    1. Definition of Small Volume Manufacturers, Small Volume Test
Groups, and Small Volume Engine Families
    a. Light-Duty and Heavy-Duty Complete Vehicles
    b. Heavy-Duty Engines
    2. Assigned Deterioration Factors
    3. Changes in Small Volume Manufacturer Status
IV. Clean Alternative Fuel Conversion Program Details
    A. New Vehicle and Engine Clean Alternative Fuel Conversion
Certification Program
    1. Applicability
    a. New Vehicles and Engines
    b. Older Vehicles and Engines
    2. Test Groups, Engine Families, and Evaporative Families
    a. Test Groups for Light-Duty and Heavy-Duty Complete Vehicles
    i. Small Volume Manufacturers
    ii. Large Volume Manufacturers
    b. Engine Families for Heavy-Duty Engines and Vehicles
    i. Small Volume Manufacturers
    ii. Large Volume Manufacturers
    c. Evaporative/Refueling Families
    3. Certification Demonstration Requirements
    a. Exhaust Emissions
    i. Light-Duty and Heavy-Duty Complete Vehicles
    ii. Heavy-Duty Engines
    b. Evaporative/Refueling Emissions
    c. Durability Demonstration and Assigned Deterioration Factors
    i. Small Volume Manufacturers
    ii. Large Volume Manufacturers
    d. On-Board Diagnostics
    4. Certification Notification Process
    a. Light-Duty and Heavy-Duty Complete Vehicles
    b. Heavy-Duty Engines
    c. Re-Certification
    5. In-Use Compliance
    B. Intermediate Age Vehicle and Engine Compliance Program
    1. Applicability
    a. Intermediate Age Vehicles and Engines
    b. Older Vehicles and Engines
    2. Test Groups, Engine Families, and Evaporative Families
    a. Test Groups for Light-Duty and Heavy-Duty Complete Vehicles
    i. Small Volume Manufacturers
    ii. Large Volume Manufacturers
    iii. Dual-Fuel Vehicle Carry Across
    b. Engine Families for Heavy-Duty Engines and Vehicles
    i. Small Volume Manufacturers
    ii. Large Volume Manufacturers
    iii Dual Fuel Engine Carry Across
    c. Evaporative/Refueling Families
    3. Demonstration Requirements
    a. Exhaust Emissions
    i. Light-Duty and Heavy-Duty Complete Vehicles
    ii. Heavy-Duty Engines
    b. Evaporative/Refueling Emissions
    c. Durability Demonstration and Assigned Deterioration Factors
    i. Small Volume Manufacturers
    ii. Large Volume Manufacturers
    d. On-Board Diagnostics
    4. Notification Process
    a. Light-Duty and Heavy-Duty Complete Vehicles and Heavy-Duty
Engines
    b. Vehicles and Engines That Were Previously Certified Under the
Clean Alternative Fuel Conversion Certification Program
    5. In-Use Compliance
    C. Outside Useful Life Clean Alternative Fuel Conversion
Compliance Program
    1. Applicability
    a. Outside Useful Life Subcategory Option
    2. Test Groups, Engine Families, and Evaporative/Refueling
Families
    3. Demonstration Requirements
    a. Option 1
    b. Option 2
    c. Option 3
    4. Notification Process
    D. Alternate Registration Approach for Newer Outside Useful Life
Vehicles and Engines

    1. NOUL Vehicles and Engines Subcategory
    a. Applicability
    b. Demonstration Requirements
V. Technical Amendments
    A. Exhaust Emission Technical Amendments
    B. Evaporative Emission Technical Amendments
VI. Environmental Benefits
VII. Associated Costs for Light-Duty and Heavy-Duty Complete
Vehicles
VIII. Associated Costs for Heavy-Duty Engines
IX. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act (RFA), as Amended by The Small
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5
U.S.C. 601 et seq.
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
X. Statutory Provisions and Legal Authority

I. Introduction

    With the vast majority of vehicles in the United States designed to
operate on gasoline or diesel fuel, there has been a longstanding and
growing interest by the public in aftermarket fuel conversion systems.
These systems allow gasoline or diesel vehicles to operate on
alternative fuels such as natural gas, propane, alcohol, or
electricity. Use of clean alternative fuels opens new fuel supply
choices and can help consumers address concerns about fuel costs,
energy security, and emissions. The U.S. Environmental Protection
Agency (EPA) is responsible for ensuring that all vehicles and engines
sold in the United States, including aftermarket conversions, meet
emission standards. Today EPA is proposing to simplify and streamline
the process by which manufacturers of clean alternative fuel conversion
systems may demonstrate compliance with these vehicle and engine
emissions requirements. The new options would reduce some economic and
procedural impediments to clean alternative fuel conversions while
maintaining environmental safeguards to ensure that acceptable emission
levels from converted vehicles are sustained.
    The conversion of vehicles or engines to operate on fuels other
than those for which they were originally designed may yield certain
benefits, but it also presents several legal and environmental
concerns. These concerns stem from Clean Air Act (CAA, the Act)
provisions intended to ensure that vehicles and engines remain clean
throughout their useful life. To this end, the Act requires EPA to
establish motor vehicle emission standards that apply throughout useful
life, and to verify through issuance of a certificate of conformity
that any vehicle or engine entered into commerce complies with the
established emission standards.\2\ Once certified, the vehicle or
engine generally may not be altered from its certified
configuration.\3\ The CAA prohibition against alteration or
``tampering'' is important because emission standards apply well beyond
a vehicle's or engine's initial entry into commerce. It is extremely
difficult to reconfigure integrated and sophisticated modern automotive
systems, precisely designed to achieve low pollution levels over time,
without negatively affecting their durability or emissions performance.
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    \2\  See CAA sections 202, 203, and 206.
    \3\ CAA section 203.
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    EPA has long recognized vehicle alteration for the purpose of clean
alternative fuel conversion as a special case because while improperly
designed or installed conversions can increase emissions, properly
engineered conversions can reduce, or at least not increase, emissions.
Furthermore use of alternative fuels can contribute to achieving other
goals such as diversifying the fuel supply through use of domestic
energy sources. Therefore, EPA has established policies through which
conversion manufacturers can demonstrate that the conversion does not
compromise emissions compliance. It has proven challenging however to
design an appropriate demonstration that ensures long-term compliance
while not imposing overly burdensome testing and administrative
requirements, especially for the small businesses that largely comprise
the conversion industry.
    The existing compliance demonstration required of conversion
manufacturers for a regulatory exemption from tampering involves
obtaining a certificate of conformity. This means that converters must
follow essentially the same rigorous certification process that EPA
requires of original equipment manufacturers (OEMs). The certification
requirements currently in place for all converters give EPA sufficient
oversight from an emissions perspective but implementation can be
problematic in certain conversion situations. The current regulations
were finalized on September 21, 1994 (59 FR 48472) and are located in
40 CFR part 85, subpart F (``the subpart F regulations''). In the 15
years since these regulations were promulgated, experience has shown
that the OEM-like certification program for aftermarket conversions is
not an optimal mechanism for ensuring compliance with applicable
emission standards, particularly for older vehicles and engines. EPA
has encountered several practical difficulties when using pre-
production certification test procedures on older vehicles and engines.
Similarly, certain aspects of the certification procedure are not well
suited to aftermarket manufacturers. Some small conversion
manufacturers, furthermore, have expressed concerns that the complexity
of the certification process presents a barrier to entry into the
alternative fuel conversions market.
    For all these reasons, EPA believes it is reasonable to modify the
current certification requirement for clean alternative fuel converters
seeking exemption from the tampering prohibition. The new program would
expand compliance options to include less burdensome demonstration
requirements that would nonetheless sustain EPA's oversight and
longstanding commitment to the environmental integrity of clean
alternative fuel conversions.
    Today, EPA is proposing a new approach that streamlines the
regulatory process and introduces new flexibilities for conversion
manufacturers, while ensuring that converted vehicles and engines
retain acceptable levels of emission control. The revised program would
also address the uncertainty some converters may experience in
determining whether a conversion constitutes tampering that could
result in liability. EPA proposes to amend the regulatory procedures in
40 CFR part 85, subpart F and part 86 to remain consistent with the CAA
yet reflect the concept that it is appropriate to treat conversion
requirements differently based on vehicle or engine age. The new
program would facilitate age-appropriate testing and compliance
procedures by placing alternative fuel conversions into one of three
categories: (1) Conversions of vehicles or engines that are ``new and
relatively-new'' (hereafter referred to as ``new'' solely for the
purpose of this preamble),\4\ (2)

conversions of vehicles or engines that are no longer new (i.e., no
longer ``new and relatively-new'') but that still fall within EPA's
definition of full useful life, ``intermediate age vehicles'', and (3)
conversions of vehicles or engines that are outside EPA's definition of
useful life.
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    \4\ See Section IV.A and proposed Sec. Sec.  85.505 and 85.510.
Proposed Sec. Sec.  85.505(b)(1) and 85.510 apply to ``new and
relatively-new'' vehicles or engines, i.e., where the date of
conversion is in a calendar year that is not more than one year
after the original model year of the vehicle or engine. In this
preamble, we refer to these ``new and relatively-new'' vehicles and
engines as ``new'' only as a shorthand reference to the proposed
category of ``new and relatively-new'' engines or vehicles. This
shorthand use of ``new'' is not intended to mean that these engines
or vehicles are ``new'' under the Act or any EPA regulations.
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    EPA is also requesting comment on whether to establish a
subcategory for vehicles and engines that exceed the useful life
threshold in mileage before they reach the threshold in years, with its
own demonstration requirement.
    Under our proposal, for the first category, conversions of new
vehicles and engines, EPA believes that a requirement for a certificate
of conformity remains appropriate because those vehicles and engines
were entered into commerce as the subject of a recently issued OEM
certificate of conformity. Such vehicles would typically have the
majority of their useful life remaining and the condition of a
relatively new vehicle or engine is still likely to be representative
of an OEM vehicle or engine used in certification testing. Furthermore,
a certification requirement for new vehicle and engine conversion would
eliminate any perceived incentive that might otherwise exist for OEMs
to circumvent certifying original-configuration alternative fuel
vehicles/engines, by instead converting already-certified traditional
fuel configurations to operate on an alternative fuel. Thus, EPA
proposes to largely retain the current certification requirements for
manufacturers of conversion systems for new vehicles and engines, while
providing some new flexibility in grouping such vehicles for
certification purposes. For the second category, intermediate age
vehicles and engines, we are proposing that manufacturers of conversion
systems demonstrate through testing that the converted vehicle or
engine still meets applicable emission standards promulgated under the
authority of the CAA section 202. For the third category, vehicles and
engines outside their full useful life, there is no longer an
applicable standard to serve as a benchmark. Since it is not possible
to assess compliance by comparing emissions to a standard, EPA is
seeking comment on three options through which manufacturers of
conversion systems for older vehicles and engines could demonstrate
that the conversion is technically viable and will not increase
emissions. The options are described in detail in Section IV.C.
    EPA is also offering an alternate approach for comment that would
create two subcategories of outside useful life vehicles. The alternate
approach is described in detail in Section IV.D.
    The primary purpose of the new program EPA is proposing today is to
facilitate the compliance process for clean alternative fuel conversion
manufacturers. Consistent with this intent, EPA would require any
conversion to be technically sound, regardless of the vehicle or engine
age category, and would continue to hold the conversion manufacturer
accountable for acceptable emissions performance once the converted
vehicle or engine is in customer service. EPA would employ compliance
tools as appropriate, such as confirmatory testing and in-use vehicle
emissions monitoring to check fleet performance, as it does with OEM
vehicles.

II. Authority

A. Vehicle and Engine Standards and Certification

    The CAA grants EPA authority to establish, administer, and enforce
emission standards for motor vehicles and engines. The CAA states that
a new vehicle or engine may not be introduced into commerce unless it
has been issued a certificate of conformity (``certificate'') by
EPA.\5\ A certificate is issued when a manufacturer has demonstrated to
EPA through a regulatory testing and data submission process that the
vehicle or engine will conform for its useful life to the standards
promulgated by EPA.\6\ Each certificate is valid for up to one model
year.\7\
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    \5\ CAA section 203(a)(1).
    \6\ CAA sections 202 and 206.
    \7\ 40 CFR 86.1848-01.
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B. Useful Life

    The CAA directs EPA to promulgate emission standards that are
applicable for a vehicle or engine's ``useful life,'' and to establish
the useful life period through regulation.\8\ The full useful life
varies among pollutant standards and among vehicle or engine
categories.\9\ For example, recent model year light-duty vehicles (cars
and small trucks) have a useful life of 10 years or 120,000 miles,
whichever comes first.\10\ Recent model year heavy-duty complete
vehicles and medium-duty passenger vehicles have a useful life of 11
years or 120,000 miles, whichever comes first.\11\ For current Otto-
cycle heavy-duty engines, the useful life is 110,000 miles or 10 years,
whichever first occurs.\12\ For current diesel heavy-duty engines (also
referred to as ``compression-ignition'' or ``diesel cycle''), there are
different useful life definitions based on gross vehicle weight,
pollutant being controlled, and test procedure, ranging from 10 years
or 110,000 miles, whichever first occurs, to 10 years or 435,000 miles
or 22,000 hours of engine operation, whichever first occurs.\13\
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    \8\ CAA section 202.
    \9\ Regulations may also include optional standards such as in
40 CFR 86.1805-04(b) and (e).
    \10\ 40 CFR 86.1805-04.
    \11\ 40 CFR 86.1805-04.
    \12\ 40 CFR 86.004-2.
    \13\ 40 CFR 86.004-2.
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C. ``Tampering'' Prohibition

    Under CAA section 203(a)(3), it is prohibited:

    (A) For any person to remove or render inoperative any device or
element of design installed on or in a motor vehicle or motor
vehicle engine in compliance with regulations under this subchapter
prior to its sale and delivery to the ultimate purchaser, or for any
person knowingly to remove or render inoperative any such device or
element of design after such sale and delivery to the ultimate
purchaser; or
    (B) For any person to manufacture or sell, or offer to sell, or
install, any part or component intended for use with, or as part of,
any motor vehicle or motor vehicle engine, where a principal effect
of the part or component is to bypass, defeat, or render inoperative
any device or element of design installed on or in a motor vehicle
or motor vehicle engine in compliance with regulations under this
subchapter, and where the person knows or should know that such part
or component is being offered for sale or installed for such use or
put to such use.

    The CAA prohibition against tampering applies to vehicles
regardless of age or mileage accumulation.\14\
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    \14\ Any alteration of a motor vehicle or engine, its fueling
system, or the integration of these systems, which may be classified
as ``tampering'' under section 203(a) and which does not satisfy the
proposed exemptions would be a violation of the CAA for which
section 205 authorizes EPA to assess penalties, currently set at up
to $37,500 per vehicle or engine. See 40 CFR part 19.
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D. Exemption for Conversions

    The CAA provides for several statutory exemptions to the
prohibition on tampering. One of these exemptions is for actions which
are ``for the purpose of a conversion of a motor vehicle for use of a
clean alternative fuel (as defined in this subchapter) and if such
vehicle complies with the applicable standard under section 202 when
operating on such fuel.'' \15\
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    \15\ CAA section 203(a).

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E. Authority for Proposed Clean Alternative Fuel Conversions Program

    The regulatory issue posed by vehicle and engine clean alternative
fuel conversions is how to design a program that allows manufacturers
to demonstrate that their conversion system warrants an exemption from
the prohibition against tampering. The 1994 rulemaking that created the
subpart F regulations stated, ``It has always been the Agency's policy
that an aftermarket conversion not degrade the emissions performance of
the original vehicle as a condition of being exempt from prosecution
for tampering violations.'' \16\
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    \16\ 59 FR 48478 (Sep. 21, 1994).
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    Today's proposal is based on EPA's interpretation that section
203(a) provides a tampering exemption for clean alternative fuel
conversions. The section 203(a) exemption from tampering applies when
the otherwise prohibited act is for ``the purpose of a conversion of a
motor vehicle for use of a clean alternative fuel (as defined in this
subchapter) and if such vehicle complies with the applicable standard
under section 202 when operating on such fuel.'' Thus, the threshold
qualification for the exemption is the proper purpose (i.e.
``conversion * * * for use of a clean alternative fuel''). The second
criterion for the exemption is compliance with the applicable standard.
    EPA is proposing a program that requires a demonstration to satisfy
both of these criteria for vehicles and engines that are still within
their useful life. For vehicles and engines that are outside their
useful life, even though a standard under CAA Section 202 is no longer
applicable, EPA believes it is important to provide a legal path under
which outside useful life vehicles and engines can be converted to use
alternative fuels. Only clean alternative fuel conversion systems that
comply with the proposed regulations would qualify for the CAA section
203(a) exemption from the tampering prohibition for application to
outside useful life vehicles and engines. Thus, EPA is proposing a
program that requires the conversion manufacturer to demonstrate that
the threshold criterion is met (i.e. ``conversion * * * for use of a
clean alternative fuel''). To meet the threshold criterion, the
conversion manufacturer would be required to demonstrate that emissions
have not degraded as a result of the clean alternative fuel conversion.
Such a demonstration would serve to maintain air quality, consistent
with the congressional intent in creating the exemption.

III. Program Design Elements Applicable to All Clean Alternative Fuel
Conversions

    The clean alternative fuel conversion program EPA is proposing is
designed to increase flexibility for conversion manufacturers while
ensuring that converted vehicles retain acceptable emission levels.
Certain aspects of the program design depend on the age of the vehicle
or engine being converted, while other program elements are common to
all conversions. This section describes those program elements which
are applicable to all clean alternative fuel conversions, regardless of
vehicle or engine age.
    In general there are three types of typical alternative fuel
conversions: (1) Those that result in dedicated alternative fueled
vehicles or engines; (2) those that result in dual-fueled vehicles or
engines; and (3) those that result in flex-fueled (also known as bi-
fueled) vehicles or engines.\17\ The first type, dedicated alternative
fueled vehicles or engines, are only capable of operating on one type
of fuel. Dual-fueled vehicles or engines, the second type, can operate
on two types of fuel, either the fuel they were originally designed for
or on a new alternative fuel. The third type, flex-fueled or bi-fueled
vehicles or engines, are able to operate on either the original fuel or
the alternative fuel, or on a mix of the two fuels. For example, an
ethanol flex-fueled vehicle operates on 100% gasoline or on any
combination of gasoline and ethanol, up to an 85% mixture of ethanol
(known as ``E85'').
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    \17\ Note that other Federal agencies may define the terms dual-
fuel and bi-fuel differently than EPA definitions.
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    EPA currently regulates all types of alternative fuel conversions
pursuant to the regulations specified in 40 CFR part 85, subpart F and
certification provisions in 40 CFR part 86 and part 1065. EPA would
continue to regulate the typical types of conversions under today's
proposal, along with newer or innovative types of fuel conversions that
do not fit neatly into one of the general categories listed above.
These include conversions of conventional gasoline or diesel vehicles
to hybrid-electric vehicles, and conversions from hybrid-electric
vehicles to plug-in hybrid electric vehicles. Since alternative fuel
conversion activity often acts as a laboratory for new fuels and new
technology, it is not possible to present an exhaustive list of covered
categories or special cases. Each special case may require unique test
procedures that are appropriate to new and developing technologies.\18\
---------------------------------------------------------------------------

    \18\ See 40 CFR 86.1840-01.
---------------------------------------------------------------------------

A. Clean Alternative Fuel Conversions

    Under today's proposal, only clean alternative fuel conversions
that are designed in accordance with EPA requirements, and for which
the manufacturer has complied with the proposed regulations would
qualify for the CAA section 203(a) exemption from the tampering
prohibition. EPA proposes clean alternative fuel conversion (also
referred to as ``fuel conversion'' or ``conversion system'') to be any
alteration of a motor vehicle or engine, its fueling system, or the
integration of these systems, that allows the vehicle or engine to
operate on a fuel or power source different from the fuel or power
source for which the vehicle or engine was originally certified; and
that is designed, constructed, and applied consistent with good
engineering judgment and in accordance with all applicable regulations.
A clean alternative fuel conversion also includes the components,
design and instructions to perform this alteration. A clean alternative
fuel conversion manufacturer (also referred to as ``conversion
manufacturer'' or ``converter'') is a company or individual that
manufactures, assembles, sells, imports, or installs a motor vehicle or
engine fuel conversion for the purpose of use of a clean alternative
fuel. To demonstrate clean alternative fuel conversion compliance,
conversion manufacturers would be required to submit data and/or other
information to EPA. For purposes of this proposal we will refer to the
appropriate submission as a ``demonstration'' and to the process of
submitting the demonstration as ``notification.'' The specifics of the
demonstration would depend on the age of vehicles or engines being
converted, but the general demonstration and notification requirements
would apply to all conversion systems. Section IV contains a detailed
description of the age-specific demonstration and notification
requirements. EPA will maintain lists of conversion systems that have
satisfied the age-appropriate demonstration requirements through the
EPA notification process and will make this information publicly
available.
    Any requirement in the existing subpart F regulations, testing or
otherwise that is not specifically addressed in this proposal would
remain in place. EPA seeks comment about whether there are aspects of
40 CFR part 86 or part 1065

implementation that have direct implications for clean alternative fuel
conversions and that should be updated to reflect the proposed changes
in requirements for clean alternative fuels conversion.

B. Good Engineering Judgment

    A clean alternative fuel conversion manufacturer would be eligible
for the exemption from the CAA tampering prohibition only if the
conversion system is designed, constructed, and applied using good
engineering judgment. EPA understands that in the context of exempting
clean alternative fuel conversions from the CAA tampering prohibition,
certain aspects of good engineering judgment may vary as a function of
clean alternative fuel type, OEM technology, and other factors. In
general, good engineering judgment would mean that the conversion
manufacturer has provided sufficient technical documentation for EPA to
ascertain that the converted vehicle or engine will continue to satisfy
emissions requirements, such as meeting standards within useful life or
maintaining emissions performance after conversion. Such documentation
would need to be submitted to EPA in writing before any conversion kit
is distributed or installed. EPA would evaluate several factors in
assessing whether a conversion system represents good engineering
judgment. These factors may include the following: whether the system
employs technology that is at least equivalent and equally effective in
design, materials and overall sophistication to that of the OEM system;
uses components that are sized to match the engine power requirements;
uses instantaneous feedback control; and maintains proper On-Board
Diagnostic (OBD) system function. Documentation provided to support a
claim of good engineering judgment may include emissions test data or
other engineering analysis to demonstrate that the conversion
technology will sustain acceptable emissions performance in the
intended vehicles or engines. Good engineering judgment also dictates
that any testing or data used to satisfy demonstration requirements
must be generated at a quality laboratory that is capable of performing
emission tests that comply with EPA regulations and that exercise good
laboratory practices.

C. Vehicle/Engine Groupings and Emission Data Vehicle Selection

    The unit of vehicle certification and compliance under the CAA and
under EPA's implementing regulations is a group of vehicles that share
similar technologies, design features, and emission control
characteristics. Thus each OEM certificate of conformity can and
usually does cover several vehicle models that have in common a unique
combination of exhaust emissions, evaporative emissions, and on-board
diagnostic (OBD) system features. The common exhaust emission system
characteristics are represented by a grouping called a ``test group.''
The common evaporative emission system characteristics are represented
by an ``evaporative/refueling family.'' The OBD system features are
represented by an ``OBD group.'' Light-duty vehicles and Otto-cycle
complete heavy-duty vehicles receive a single certificate covering a
unique combination of test group, evaporative/refueling family, and OBD
group.
    The unit of certification is slightly different for heavy-duty
engines. Instead of receiving a single certificate that covers both
exhaust and evaporative emission control characteristics, heavy-duty
engines are issued separate certificates by ``engine family'' for
engines having common exhaust characteristics, and by evaporative/
refueling families, if applicable.\19\ Even though heavy-duty engine
certificates are based on a different unit, the concept behind
allowable groupings remains consistent between light-duty vehicle and
heavy-duty engine certification and compliance. Groupings share similar
technologies, design features, and emission control characteristics. In
this proposal, EPA is proposing to expand the grouping flexibility for
conversion manufacturers by permitting somewhat broader grouping
criteria for both light-duty vehicles and heavy-duty engines than those
available for OEM certification.
---------------------------------------------------------------------------

    \19\ Certain fuels such as diesel fuel do not have heavy-duty
evaporative emissions standards.
---------------------------------------------------------------------------

    The general concept behind groupings for the conversion program
would apply to all vehicle and engine age categories, although the
specific criteria for designating conversion groups would vary somewhat
among the new, intermediate age, and outside useful life programs (see
Section IV). Conversion manufacturers would use the applicable criteria
to designate a conversion group, and would select a ``worst case''
emissions data vehicle (EDV) or emission data engine (EDE) to represent
the group for demonstration and notification purposes. Consistent with
current requirements, the conversion EDV/EDE would be expected to
represent the most challenging emissions compliance technology of all
the models it represents. Use of a worst-case emission data vehicle or
engine gives EPA confidence that all models covered by a certificate in
the case of OEM certification, or by EPA's acceptance of the conversion
group demonstration in the case of conversion, comply with all
applicable emission requirements. These may include exhaust emission
standards, evaporative emission standards, OBD compliance requirements,
and other criteria. Therefore conversion manufacturers may need to
submit data from more than one EDV or EDE to represent the worst case
condition for each of the applicable requirements.

D. Flex-Fuel (Bi-Fuel) and Dual-Fuel Conversions

    EPA regulations require flex-fueled and dual-fueled vehicles and
engines to comply with all requirements established for each fuel or
blend of fuels on which the system is capable of operating.\20\ These
requirements would continue to apply to flex- and dual-fuel
conversions. Certain demonstration requirements could potentially be
waived for clean alternative fuel conversions if the conversion
manufacturer has not altered the OEM configuration of the vehicle or
engine when operating on its original fuel. However, if the conversion
of the vehicle or engine to dual-fuel or flex-fuel operation alters the
OEM certified configuration in any way while operating on the original
fuel, then EPA would require the conversion manufacturer to demonstrate
compliance for each fuel with all applicable exhaust emissions,
evaporative/refueling emissions, and OBD demonstration and notification
requirements, appropriate for the age of the vehicle as described in
Section IV.
---------------------------------------------------------------------------

    \20\ See, e.g., 40 CFR 86.1810-01, 40 CFR 86.1811-04, 40 CFR
86.1812-01, 40 CFR 86.1813-01, 40 CFR 86.1814-01, 40 CFR 86.1814-02,
40 CFR 86.1815-01, 40 CFR 86.1815-02, 40 CFR 86.1816-05, 40 CFR
86.1816-08.
---------------------------------------------------------------------------

    EPA proposes to continue to allow a statement of compliance in lieu
of test data for operation on the original fuel if the conversion
manufacturer can attest that the conversion retains all the OEM fuel
system, engine calibration, and emission control system functionality
when operating on the fuel with which the vehicle was originally
certified and the conversion retains all the functionality of the OEM
OBD system (if so equipped) when operating on the fuel with which the
vehicle was originally certified. The conversion manufacturer would
still be required to submit data demonstrating compliance with the
applicable requirements when the

vehicle is operating on the new alternative fuel.\21\
---------------------------------------------------------------------------

    \21\ Compliance testing and data submission requirements will
vary by vehicle age and mileage. See Section IV.
---------------------------------------------------------------------------

    Because a flex-fuel vehicle or engine operates on a fuel mixture,
with the fuels combusted together at a variety of fuel ratios, EPA
would generally require a flex fuel vehicle or engine conversion
manufacturer to demonstrate compliance with applicable requirements for
each fuel. The conversion manufacturer may need to conduct testing on
multiple fuel ratios to adequately represent worst case emission
scenarios.\22\ Conversion manufacturers should work with EPA to make
good engineering judgment decisions about the worst case emission data
vehicle or engine requirements for flex-fuel vehicles and engines.
---------------------------------------------------------------------------

    \22\ Compliance testing and data submission requirements will
vary by vehicle age and mileage. See Section IV.
---------------------------------------------------------------------------

    EPA has specific concerns about canister purge in dual-fuel
conversions because of potential for uncontrolled evaporative emissions
when the converted vehicle or engine is operating on the new
alternative fuel. Although much of the OEM functionality is likely to
remain fully operational on the original fuel after conversion to dual-
fuel, OEM canister purge may have been designed to depend on the
frequency and duration of engine operation on the original fuel.
Therefore, for dual-fuel conversions, EPA proposes to require the
conversion manufacturer either to test canister purge and submit data,
or to provide a separate attestation for evaporative emission canister
purge. For vehicles and engines converted to dual-fuel operation, the
attestation would include statements that the evaporative emissions
canister purge continues to operate as originally designed while
operating on each fuel. EPA would expect the clean alternative fuel
conversion manufacturer to supply a description of the canister purge
operation while the vehicle or engine is operating on the alternative
fuel. EPA would expect that the canister purge while operating on the
alternative fuel is identical to the OEM canister purge operation.

E. Vehicle and Packaging Labels

    Vehicle and engine labeling requirements for clean alternative fuel
conversions are currently set forth in 40 CFR 85.505. These regulations
list the information that must be included on the label and require the
label to be permanently affixed adjacent to the OEM vehicle emissions
control information (VECI) label. EPA proposes to maintain these
labeling requirements for clean alternative fuel converted vehicles and
engines. We also propose to require some additional content on the
vehicle conversion label. The newly required content would include the
conversion manufacturer's evaporative/refueling family and test group
or engine family and a statement specifying the minimum age and/or
mileage requirements, OEM model year of vehicles, and the specific OEM
test groups or engine families to which the conversion system is
applicable. Conversion manufacturers would be required to submit the
vehicle label information to EPA as part of the notification process.
Failure to supply or install compliant labels would leave conversion
manufacturers and installers subject to prosecution for tampering.
    It has been suggested that conversion manufacturers be required to
submit to EPA Vehicle Identification Numbers (VIN) information for all
converted vehicles, in addition to vehicle label information. The
reason for VIN tracking would be to assist automotive dealers or repair
facilities, State Inspection and Maintenance program personnel, and
others who might need to know whether a vehicle or engine has been
altered from its OEM configuration. EPA requests comment as to whether
converters should submit VIN tracking information to EPA and whether
EPA should make such information publicly available.
    EPA proposes that any packaging label information must be
consistent with the conversion manufacturer's demonstration and
notification to EPA. This would include the minimum vehicle or engine
age requirements and OEM manufacturer, model year, carline (model) and
vehicle test groups or engine families to which the clean alternative
fuel conversion may be applied.
    EPA seeks comment on whether the proposed information content of
the vehicle and packaging labels is appropriate for vehicles and
engines that have been converted to operate on a clean alternative
fuel.

F. Marketing

    EPA would continue to expect that any marketing material associated
with any aftermarket fuel conversion product would be consistent with
and not contravene the information required on the vehicle or packaging
labels. For instance, the marketing of the applicability of the product
must be consistent with the label information to ensure the product
would not be misapplied to other vehicles or engines.\23\
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    \23\ If any marketing material implies or states that the
installation of the conversion system is legal or appropriate for
vehicles/engines not listed in the documentation provided to EPA,
EPA would deem the marketing material to be evidence that the
marketer caused a customer to install an inappropriate conversion
system and thus tampered with the vehicle.
---------------------------------------------------------------------------

G. Compliance

    Clean alternative fuel conversion manufacturers would continue to
be subject to all certification requirements and warranty, defect, and
recall requirements applicable to new vehicle and engine manufacturers
in 40 CFR parts 85 and 86.\24\
---------------------------------------------------------------------------

    \24\ 40 CFR 85.503 and 85.504 and 59 FR 48478.
---------------------------------------------------------------------------

    EPA plans to audit conversion manufacturers and enforce against
violations.
1. Emission Standards
    EPA has previously determined that it is appropriate to require
vehicle and engine fuel conversions to meet the same emission standard
as required for the originally certified OEM vehicle or engine.\25\ OEM
standards would continue to apply for the required test cycles,
including intermediate useful life standards and full useful life
standards where applicable.\26\ If a converter designates a conversion
group that combines multiple OEM test groups/engine families, the most
stringent OEM standards represented within that group would become the
applicable standards for the conversion group. For example, if a
converter establishes a conversion test group that includes OEM test
groups originally certified to Tier 2, Bin 4 and Bin 5 standards, all
the vehicles in the combined conversion test group would be subject to
more stringent Tier 2, Bin 4 standard.
---------------------------------------------------------------------------

    \25\ 59 FR 48488.
    \26\ In almost all cases the standards in place for an OEM
vehicle or engine will continue to apply to the converted vehicle or
engine. The only exceptions involve fuel specific standards (or
exemptions from standards) that were not applicable to the OEM
configuration but are applicable to the converted configuration, or
vice versa. In those cases the converted vehicle/engine will be held
to the fuel-specific standard that would have been in place for an
OEM vehicle/engine certified to operate on that fuel. For example,
diesel-fueled vehicles are currently exempt from evaporative
emission standards but vehicles fueled with most other fuels are
not. If a diesel fuel vehicle is converted to run on an alternative
fuel, the converted vehicle would be held to the evaporative
emission standards that would have applied to an OEM vehicle
certified operating on that fuel.
---------------------------------------------------------------------------

a. Light-Duty and Heavy-Duty Complete Vehicle Gross Vehicle Weight
Classes and Alternative Fuel Exceptions
    Emission standards for light-duty passenger cars, light-duty
trucks,

medium-duty passenger vehicles, and Otto-cycle heavy-duty complete
vehicles less than 14,000 pound gross vehicle weight are codified in 40
CFR part 86, subpart S.\27\ Standards are specific to vehicle type and
gross vehicle weight ratings.
---------------------------------------------------------------------------

    \27\ For purposes of this NPRM, this group of vehicles will be
described as light-duty and heavy-duty complete vehicles from this
point forward.
---------------------------------------------------------------------------

    Light-duty vehicles, both OEM vehicles and conversions, are
currently exempt from Supplemental Federal Test Procedure (SFTP)
standards and cold carbon monoxide (CO) standards when certified on
alternative fuels.\28\ However, for dual-fuel and flex-fuel (bi-fuel)
light-duty vehicles, SFTP and cold CO standards do apply while the
vehicle is operating on gasoline or diesel fuel.\29\ At this time, EPA
is not proposing any changes to the regulations in 40 CFR 86.1810-
01(i)(4). However, EPA is requesting comment on whether SFTP standards
and testing are appropriate for alternative fueled light-duty vehicles;
both OEM vehicles and clean alternative fuel conversions (see Section
IV.A.3.a).\30\ In the future, if SFTP standards are amended to apply to
vehicles operated on alternative fuels, these standards and test
procedures would also be applicable to fuel conversions.
---------------------------------------------------------------------------

    \28\ All medium-duty passenger vehicles are also currently
exempt from SFTP standards, regardless of fuel type. 40 CFR 85.1811-
04(f)(1). Medium duty passenger vehicles, operating on gasoline, do
have a cold CO standard (40 CFR 86.1811-04(g)).
    \29\ 40 CFR 86.1810-01(i)(4) and 40 CFR 86.1811-04(g).
    \30\ 40 CFR 86.1811-04(f).
---------------------------------------------------------------------------

b. Heavy-Duty Engine Types and Gross Vehicle Weight Classes
    Heavy-duty engine standards are categorized in several ways. There
are divisions by engine type, either compression ignition or spark
ignition, and there are divisions by application gross vehicle weight.
Standards for heavy-duty engines are described in 40 CFR part 86,
subpart A. Generally, heavy-duty engine standards apply to engines
installed in vehicles with a gross vehicle rating (GVWR) greater than
8,500 pounds. As noted in Section III.G.1, Otto-cycle complete vehicles
must be certified using standards and procedures set forth in 40 CFR
part 85, subpart F. In addition, Otto-cycle incomplete vehicles with
GVWR up to 14,000 pounds which were optionally certified by the OEM
using the provisions found in 40 CFR part 86, subpart S, would also
follow these provisions for conversion to a clean alternative fuel.\31\
OEM manufacturers of compression ignition engines in complete heavy-
duty vehicles between 8,500 and 14,000 pounds may optionally chassis
certify using the provisions in 40 CFR part 86, subpart S. The clean
alternative fuel conversion manufacturer would use the same
certification provisions (engine or chassis-certification provisions)
that the OEM used at the time of the original certification.
---------------------------------------------------------------------------

    \31\ As described in Section III.G.1.a of this preamble.
---------------------------------------------------------------------------

c. Dual-Fuel Standards
    EPA as a matter of policy requires dual fuel vehicles and engines
to certify operation on both fuel types to the same emission standards.
A dual-fuel natural gas-gasoline vehicle, for example, would need to
certify to the same Tier 2 bin level for both natural gas and gasoline.
The same policy applies to evaporative/refueling standards and family
emission levels (FELs) for engines. Therefore, conversion manufacturers
of systems that convert single-fuel OEM systems to dual-fuel systems
must certify to the OEM standard, even if test data demonstrate that
the converted vehicle or engine is able to meet a lower standard while
operating on the alternative fuel. If a conversion manufacturer wishes
to certify to a lower standard on both fuels, a demonstration would be
required on both fuels showing compliance with the said standard. This
policy would continue to apply to all vehicle fuel conversions,
regardless of age or compliance program.\32\ In each case the
notification process for a dual-fuel vehicle will require separate
submissions for groups of vehicles with different standards. However,
test data from an EDV or EDE demonstrating compliance with a lower
standard may be able to be carried across to other vehicles or engines
that meet the criteria available for the combination of exhaust groups,
such as test groups and engine families, described in Sections IV.A.2
and IV.B.2.
---------------------------------------------------------------------------

    \32\ Compliance testing and data submission requirements will
vary by vehicle age and mileage. See Section IV.
---------------------------------------------------------------------------

2. Useful Life
    In the rulemaking that established the existing aftermarket
conversions certification program, EPA determined it was not
appropriate to extend the useful life of a conversion beyond that of
the original vehicle given that conversions generally rely on many
original vehicle components for proper operation.\33\ EPA's revised
program would leave this determination unchanged such that the
applicable useful life of a converted vehicle or engine would not
extend beyond the useful life of the original vehicle or engine. Thus,
the useful life of the conversion would continue to end at the same
time as the useful life of the original vehicle, including any optional
useful life standards to which the OEM certified the original
vehicle.\34\
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    \33\ 59 FR 48488.
    \34\ Examples of optional useful life include those described in
40 CFR 86.1805-04(b) and (e).
---------------------------------------------------------------------------

3. On Board Diagnostics (OBD)
    As part of the good engineering judgment requirement described in
Section III.B, OEM vehicles or engines subject to OBD requirements
would also be required to have properly functioning OBD systems once
converted.\35\ OBD systems are designed to monitor critical vehicle or
engine emission control components and to alert the vehicle operator or
State emissions inspection official to malfunction, deterioration, or
other problems that might cause excessive emissions. States rely on OBD
systems to flag vehicles that exceed Inspection and Maintenance
thresholds and may require repair. OBD systems are also designed to
store diagnostic information in the vehicle's computer to assist
technicians in diagnosing and repairing the problem EPA is proposing
that the conversion OBD system would need to include any new monitoring
capability necessary to identify potential emission problems associated
with the new fuel. In addition, consistent with other EPA regulations,
EPA proposes that any dual-fuel clean alternative fuel conversion would
require the OBD to remain fully functional on the original fuel.\36\
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    \35\ OBD systems were phased in for light-duty and heavy-duty
complete vehicles beginning in 1994. See 40 CFR 86.1806-01, 86.1806-
04, and 86.1806-05. OBD systems were phased in for heavy-duty
vehicles weighing less than 14,000 pounds GVWR beginning in 2004. 40
CFR 86.005-17. OBD requirements for heavy-duty engines for vehicles
over 14,000 pounds begin phase-in in 2010. 40 CFR 86.005-18.
According to 40 CFR 86.010-18(o)(1)(v), engines in vehicles over
14,000 pounds GVWR certified on alternative fuels are exempt from
OBD requirements for model years 2010-2012.
    \36\ Multi-fueled vehicles must be compliant on both fuels. See,
for example, 40 CFR 86.1811-01.
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4. Durability Testing
    Manufacturers must conduct durability testing for both exhaust and
evaporative emissions to determine expected useful life deterioration.
Durability procedures for light-duty vehicles and heavy-duty complete
vehicles are codified in 40 CFR 86.1823-01, 86.1824-01, 1824-07, 1824-
08, and 86.1825-01, 85.1825-08. Durability procedures for heavy-duty
engines are currently set forth in 40 CFR 86.096-24, 86.098-24, 86.001-
24,

86.094-26, 86.001-26, 86.0004-26, 86.094-28, et al. In lieu of
durability testing, these regulations provide that small volume
manufacturers may be eligible to utilize EPA assigned deterioration
factors to predict the emission rates at the end of a vehicle or
engine's useful life. See Section IV.B.3.c for more information.
    EPA requests comment as to whether the durability procedures that
would be established under this proposal are appropriate for small and
large volume conversion manufacturers. EPA also requests comment on
whether the proposed procedures provide adequate assurance that the
emission control systems in converted vehicles and engines will
continue to function properly over time.
5. Warranty
    The CAA requires manufacturers to warrant that a vehicle or engine
is (1) designed, built, and equipped to conform to applicable
regulations and (2) free from defects in material and workmanship which
cause the vehicle or engine to fail to conform to applicable
regulations for its useful life.\37\ For light-duty vehicles, this
defect warranty is applicable through two years or 24,000 miles of use
(whichever first occurs).\38\ Specified major emission control
components, including catalysts, engine control units (ECUs), and OBD
are warranted for eight years or 80,000 miles of use (whichever first
occurs).\39\ For Otto-cycle heavy-duty engines and vehicles (complete
and incomplete) and light heavy-duty diesel engines, the warranty
period is at least 5 years or 50,000 miles, whichever first occurs. For
all other heavy-duty diesel engines, the warranty period is at least 5
years or 100,000 miles, whichever first occurs. For all heavy-duty
engines the warranty period may not be shorter than the basic
mechanical warranty period that the original equipment manufacturer
provides.\40\ Conversion manufacturers must accept in-use liability for
warranty and recall as a condition for gaining exemption from tampering
under EPA's current aftermarket conversions certification program.
---------------------------------------------------------------------------

    \37\ 42 U.S.C. 7541.
    \38\ CAA section 207(i)(1).
    \39\ CAA section 207(i)(2).
    \40\ 40 CFR 86.004-2.
---------------------------------------------------------------------------

    EPA would continue to apply this approach to in-use liability for
warranty under the revised clean alternative fuel conversions program
being proposed today. Under this policy, the clean alternative fuel
conversion manufacturer would normally be held accountable for fixing
problems that occur as the result of conversion, while the OEM would
generally retain responsibility for the performance of any parts or
systems that retain their original function following conversion and
are unaffected by the conversion. It is important that both clean
alternative fuel conversion manufacturers and consumers understand
these provisions because they could result in a transfer of warranty
liability for certain failed components from the OEM to the converter.
A reasonable indicator of cause and accountability might be whether the
failure of the part or system is also occurring in non-converted
configurations of the same vehicle. If so, the problem is most likely
not related to conversion and the OEM would typically remain liable for
performing repairs. If only converted vehicles are experiencing the
problem, it would be appropriate to trace the problem to the conversion
and to hold the converter responsible for warranty repairs. These views
are consistent with the liability provisions in the existing subpart F
regulations.\41\ EPA seeks comment on the best way to inform consumers
about the possibility that converting their vehicle or engine, even
with an EPA compliant system, may transfer portions of their OEM
warranty liability to the converter.
---------------------------------------------------------------------------

    \41\ 59 FR 48488.
---------------------------------------------------------------------------

6. Other Provisions Applicable to Conversion Manufacturers
    As stated above, all clean alternative fuel conversion
manufacturers would continue to be subject to labeling, warranty, and
certification requirements applicable to new vehicle and engine
manufacturers in 40 CFR parts 85 and 86.\42\ In addition, there are
recall and defect reporting requirements in 40 CFR 85.503 and 85.504
which would also continue to apply.
---------------------------------------------------------------------------

    \42\ 40 CFR 85.504 and 59 FR 48478.
---------------------------------------------------------------------------

    Conversion manufacturers are subject to the recall regulations in
40 CFR part 85, subpart S and the emission defect reporting
requirements in 40 CFR part 85, subpart T. If EPA determines that a
substantial number of vehicles or engines in a class or category do not
meet applicable emission standards in actual use even though they are
properly maintained and used, EPA can require the manufacturer to
recall and fix affected vehicles.\43\ All manufacturers are also
required to report to EPA certain defects affecting emission-related
parts.
---------------------------------------------------------------------------

    \43\ CAA section 207(c).
---------------------------------------------------------------------------

    Sections 206, 207 and 208 of the Act authorize EPA to establish
procedures to ensure that production vehicles and engines comply with
emission standards when they are new and continue to comply with
emission requirements after they are in customer service. These
provisions provide EPA broad authority to conduct testing as the
Administrator deems necessary to monitor in-use vehicle and engine
compliance. EPA intends to extend these emission testing programs to
cover clean alternative fuel conversions as well as OEM vehicles.
7. Misapplication
    EPA may revisit the age-based approach being proposed today should
there at any time be evidence of widespread conversion system
misapplication that can be traced to differences among the age-based
demonstration or notification requirements. For example, if exempted
outside useful life conversion systems are commonly marketed to
vehicles that are still within their useful life, EPA would not only
consider the misapplication to be tampering, but would also consider
revising this rule to eliminate or constrain the age-based
demonstration approach.

H. Regulatory Procedures for Small Volume Manufacturers and Small
Volume Test Groups

    EPA regulations afford certain flexibilities to small volume
manufacturers in recognition of special compliance challenges they may
face. The clean alternative fuels industry has historically been
comprised of companies that qualify for small volume manufacturer
status. Existing eligibility criteria and special procedures available
to small volume conversion manufacturers, along with changes under
today's proposal, are discussed below.
1. Definition of Small Volume Manufacturers, Small Volume Test Groups,
and Small Volume Engine Families
a. Light-Duty and Heavy-Duty Complete Vehicle Small Volume
Manufacturers and Small Volume Test Groups
    EPA has regulatory procedures specific to light-duty and heavy-duty
complete vehicle small volume manufacturers and small volume test
groups, set forth in 40 CFR 86.1838-01. A manufacturer is eligible for
small volume manufacturer status for light-duty and heavy-duty complete
vehicle procedures, if the manufacturer's annual model year motor
vehicle and engine total sales volume in all States and territories of
the United States (or aggregate sales volume for manufacturers in an
aggregate

relationship) is less than 15,000 units.\44\ (For sales aggregation
rules for related manufacturers, refer to 40 CFR 86.1839-01(b)(3)). A
large volume manufacturer may also use small volume manufacturer
certification procedures for test groups of vehicles which total less
than 15,000 units. For small volume test group eligibility criteria for
large volume manufacturers who participate in aggregate relationships,
refer to 40 CFR 86.1838-01(b)(2) for more details.
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    \44\ 40 CFR 86.1838-01.
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b. Heavy-Duty Engine Small Volume Manufacturers
    The EPA regulatory provisions for small volume heavy-duty engines
are promulgated in 40 CFR 86.094-14, 86.096-14 and 86.098-14. Heavy-
duty engine small volume manufacturer status is tiered. Certain
procedures apply to manufacturers with aggregate sales of less than 301
units, and other procedures may apply to manufacturers with aggregate
sales volumes less than 10,000 units. For sales aggregation rules,
refer to 40 CFR 86.094-14(b)(2) and 86.094-14(b)(5).
2. Assigned Deterioration Factors
    All light-duty and heavy-duty complete vehicle small volume
manufacturers or qualified small volume test groups are eligible to use
assigned deterioration factors (DFs) in lieu of durability testing to
predict emission rates at the end of a vehicle's useful life.\45\ EPA
assigned deterioration factors are authorized in 40 CFR 86.1826-01 and
are periodically updated by EPA via manufacturer guidance letters.\46\
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    \45\ 40 CFR 86.1838-01(c)(1). Manufacturers not eligible for
small volume manufacturer or small volume test group status are
required to follow durability procedures in 40 CFR 86.1823-01,
86.1923-08, 86.1824-01, 86.1824-07, 86.1824-08, 86.1825-01, and
86.1825-08.
    \46\ The current light-duty light duty and heavy-duty complete
vehicles assigned deterioration factor guidance document issued
pursuant to 40 CFR 86.1826(b)(1)(ii) and (b)(2)(i)(c), is available
electronically at http://iaspub.epa.gov/otaqpub/display_
file.jsp?docid=14285&flag=1. The current heavy-duty engine assigned
deterioration guidance letter is available electronically at http://
iaspub.epa.gov/otaqpub/display_file.jsp?docid=14183&flag=1.
---------------------------------------------------------------------------

    Heavy-duty engine small volume manufacturers may also be eligible
for assigned DFs instead of conducting durability demonstrations.\47\
Under the regulations, manufacturers with sales volumes of less than
10,000 units are eligible to use assigned DFs determined by EPA.
---------------------------------------------------------------------------

    \47\ 40 CFR 86.094-14, 40 CFR 86.095-14, 40 CFR 86.096-14, 49
CFR 86.098-14.
---------------------------------------------------------------------------

    Because assigned deterioration factors are determined assuming the
vehicle or engine is new, EPA proposes to allow small volume conversion
manufacturers to use deterioration factors, proportionate to the
vehicle or engine age under certain conditions. This would help create
a level playing field for older vehicles and engines that have already
experienced some of their expected emissions degradation. EPA proposes
that conversion manufacturers are eligible to use scaled DFs for
vehicles or engines that have accumulated more than 10,000 miles. EPA
proposes to allow a proportionate scaling of the EPA assigned
deterioration factor, if applicable, to demonstrate compliance with the
intermediate and/or full useful-life standards. See Section IV.B.3.c.i
for more detail.
3. Changes in Small Volume Manufacturer Status
    If a conversion manufacturer's annual sales volume may surpass the
threshold for small volume manufacturer or test group status for a
given model year,\48\ the conversion manufacturer must satisfy the
regulatory requirements required for large volume manufacturers or test
groups, even if the conversion manufacturer initially complied properly
(in a previous model year) with the small volume requirements.
Conversion manufacturers should be aware that this status change could
result in new demonstration and notification requirements involving new
testing under both the new and intermediate age programs. EPA proposes
to require conversion manufacturers to report to EPA the number of
conversion systems they have sold annually in an end-of year
submission.
---------------------------------------------------------------------------

    \48\ Manufacturers of conversion systems for intermediate age
and outside useful life vehicles would use calendar year sales
volume to determine small volume manufacturer status.
---------------------------------------------------------------------------

    A change from small volume status to large volume status could
occur in several different situations. First, if a conversion
manufacturer is required to recertify a vehicle or engine (see Section
IV.A.4.c for an explanation of recertification) after a sales volume
status change, all large volume test procedures and requirements would
need to be conducted prior to the issuance of the new certificate.
Second, if a small volume conversion manufacturer crosses the annual
sales volume threshold and becomes a large volume conversion
manufacturer, the conversion manufacturer would need to update their
demonstration and complete all applicable large volume requirements for
the intermediate age vehicle or engine conversions which are no longer
eligible for small volume manufacturer or test group.

IV. Clean Alternative Fuel Conversion Program Details

    As summarized earlier in this Notice, EPA is proposing to revise
the demonstration and notification procedures for clean alternative
fuel conversions based on the age of the vehicle or engine to be
converted. All conversion manufacturers would be required to
demonstrate to EPA that the conversion satisfies technical criteria to
qualify as a clean alternative fuel conversion, but demonstration and
notification requirements would be different depending on vehicle or
engine age. The age-specific requirements are summarized in Table IV-1
and are presented in detail below.
    The age-based demonstration and notification requirements that EPA
is proposing stem from both legal and practical considerations. The
proposed distinctions between the demonstration required for new,
intermediate age, and outside useful life vehicles and engines address
the issues posed by the absence of applicable emission standards for
converted vehicles and engines that have exceeded full useful life. At
the same time, the proposed approach recognizes that new vehicles and
engines, at the time of conversion, should resemble the certified OEM
configuration from the perspective of emissions degradation and should
therefore be held to the same durability and deterioration factor
demonstrations required for OEM certification. Intermediate age
vehicles and engines fall between the new and outside useful life
categories. While useful life standards still apply, certain
certification requirements are no longer suitable for aging vehicles
and engines.
    As with demonstration protocols, EPA believes different
notification protocols are appropriate for the three age classes. The
proposed notification protocols reflect the level of detail EPA has
determined to be necessary for conversion manufacturers to adequately
document and for EPA to review the required emissions demonstration.
The proposed age-based notification system would streamline the
notification process and would create a simple system that both small
and large conversion manufacturers could easily understand and follow.

                                                  Table IV-1--Overview of Proposed Program Elements 49
--------------------------------------------------------------------------------------------------------------------------------------------------------
                              Vehicle/engine age                                  Conversion manufacturer requirement                       Compliance
------------------------------------------------------------------------------------------------------------------------- Certificate of      detail
                                                           Example for 2010                                                 conformity       preamble
             Category                  Applicability             \50\              Demonstration         Notification                         section
--------------------------------------------------------------------------------------------------------------------------------------------------------
New..............................  MY > = current        MY 2009, 2010, 2011   Exhaust, Evap, and    Certification                   Yes            IV.A
                                    calendar year - 1.    and < useful life     OBD testing \51\.     Application.
                                                          mileage.
Intermediate age.................  MY < = current        MY 2001, 2002, 2003,  Exhaust and Evap      Data Submission                  No            IV.B
                                    calendar year - 2     2004, 2005, 2006,     testing \51\ + OBD    \52\.
                                    and within useful     2007, 2008 and <      attestation.
                                    life.                 useful life mileage.
Outside useful life..............  Exceeds useful life.  MY 2000 and older or  See Sec. IV.C for     See Sec. IV.C for                No            IV.C
                                                          > full useful life    options.              options \52\.
                                                          mileage.
--------------------------------------------------------------------------------------------------------------------------------------------------------

A. New Vehicle and Engine Clean Alternative Fuel Conversion
Certification Program
---------------------------------------------------------------------------

    \49\ See Section X of this preamble for more compliance details.
    \50\ This example is for Light-duty Tier 2 vehicles which have a
useful life of 10 years or 120,000 miles.
    \51\ Exhaust and Evap refers to all exhaust emission testing and
all evaporative emission and refueling emission testing required for
new vehicle certification, unless otherwise excepted.
    \52\ EPA is proposing that the compliance notification process
for intermediate age and outside useful life conversion would be
electronic submission of data and supporting documents.
---------------------------------------------------------------------------

    EPA proposes to require that conversions of new vehicles and
engines (as defined for purposes of this preamble) \53\ be covered by a
certificate of conformity in order to qualify for an exemption from the
tampering prohibition. EPA also proposes to allow, but not require,
conversions of intermediate age vehicles and engines to qualify for an
exemption from the tampering prohibition by obtaining a certificate of
conformity (see Sections IV.A.1.b. and IV.B). Certification would
satisfy the statutory tampering exemption prerequisites that the
conversion is ``for use of a clean alternative fuel'' and that the
converted vehicle ``complies with the applicable standards under
section 202.'' \54\
---------------------------------------------------------------------------

    \53\ See footnote 4.
    \54\ CAA 203(a)(3).
---------------------------------------------------------------------------

    EPA believes that certification of clean alternative fuel
conversions remains an appropriate demonstration of compliance with
useful life standards for new vehicles and engines. New vehicles and
engines have not yet experienced deterioration and are still likely to
be representative, for purposes of emissions, of the technical
condition of the vehicle or engine that the OEM used for EPA
certification. Thus the certification process is suitable for and may
be directly applied to new vehicle and engine clean alternative fuel
conversions.
    EPA also believes that a certification demonstration requirement
for new vehicle and engine conversions is prudent to maintain a level
playing field for OEMs and conversion manufacturers. We believe it is
important to prevent the potential opportunity for an OEM to circumvent
the new vehicle and engine certification process by choosing to certify
and then convert a traditionally-fueled vehicle or engine rather than
to certify it in an alternative fuel configuration in the first place.
New vehicles represent the vast majority of clean alternative fuel
conversion activity. For model year 2009, only two light duty vehicle
fuel conversion certificates out of 60 were issued based on data from a
vehicle that was more than one year old. EPA believes that a new
vehicle and engine certification requirement would continue to cover
most newly developed clean alternative fuel conversion systems and
therefore would preserve existing EPA control over their technical
viability and environmental performance. While new vehicle and engine
clean alternative fuel conversion manufacturers would still be subject
to certification requirements under today's proposal, they would
benefit from reduced burden because the intermediate age compliance
program (see Section IV.B) would allow conversion manufacturers to
continue to sell their products as vehicles and engines age without
renewing certificates and paying certification fees after vehicles and
engines are about two years old.\55\
---------------------------------------------------------------------------

    \55\ Conversion manufacturers would be able to use their
certification data to qualify for a tampering exemption under the
intermediate age vehicle/engine program described in Section IV.B.
---------------------------------------------------------------------------

    This proposal leaves the existing regulatory procedures for
demonstration, notification, and compliance documents relatively
unchanged for clean alternative fuel conversion of new vehicles and
engines. The demonstration of compliance with applicable standards
would use the same certification procedures required of conversion
manufacturers under the existing subpart F regulations with a few
technical amendments and other allowances.\56\ The notification process
in existing subpart F regulations would also remain unchanged for
conversion of new vehicles and engines. Conversion manufacturers would
continue to submit applications, including test data, certification
fees, and other required information to EPA on an annual basis. The
compliance document, a certificate of conformity, would also remain
unchanged for conversion of new vehicles and engines.
---------------------------------------------------------------------------

    \56\ Technical amendment proposals are described in Section V.
See section IV.B.3.c.i for a description of the proposed scaling of
assigned deterioration factors for small volume manufacturers who
conduct demonstration testing on a vehicle with over 10,000 miles.
---------------------------------------------------------------------------

1. Applicability
a. New Vehicles and Engines
    EPA proposes to define ``new and relatively-new'' (as discussed
above in Section I in this preamble we refer to ``new and relatively-
new'' vehicles and engines as ``new'') vehicle or engine clean
alternative fuel conversions as those for which the date of conversion
is in a calendar year that is not more than one year after the original
model year (MY) of the vehicle or engine.\57\ For example, in calendar
year 2010, certified conversion systems would be

required for MY 2009, MY 2010, and MY 2011 vehicles or engines.
---------------------------------------------------------------------------

    \57\ OEM model years are often introduced ahead of the calendar
year. Thus, to calculate which conversions must be certified,
subtract the original vehicle model year from the current calendar
year. If the difference is one or less than one, then a certified
conversion is required to qualify for the tampering exemption. If
the difference is more than one, then the conversion may comply with
the intermediate age or outside useful life provisions as
applicable.
---------------------------------------------------------------------------

    As stated previously, EPA believes that certification is an
appropriate requirement for new vehicles and engines because their
emissions and mileage accumulation still largely reflect the vehicle's
condition at the time of OEM certification. For consumer and conversion
manufacturer clarity, it makes sense to compare vehicle model year to
the current calendar year. This can be accomplished by applying the
formula presented in Table IV-1 above. In practice this means that
certification would be required for vehicles or engines that are less
than about two years old.
    EPA is proposing an age threshold of less than about two years old
for the new vehicle and engine certification requirement on the basis
of historical conversion certification age patterns. EPA requests
comment regarding whether EPA has properly identified the vehicle and
engine age range for which certification is appropriate and should be
required for conversions. In particular EPA requests emissions or other
data to support comments suggesting a different age range than the
proposed two year period.
b. Older Vehicles and Engines
    Manufacturers of conversion systems for vehicles and engines that
are older than the age range defined above for new vehicles and
engines, but still fall within the original vehicle's or engine's
useful life, may opt for certification as their demonstration of
compliance with useful life standards. These systems are also eligible
for the intermediate age notification program described in Section
IV.B.
2. Test Groups, Engine Families and Evaporative/Refueling Families
a. Test Groups for Light-Duty and Heavy-Duty Complete Vehicles
i. Small Volume Manufacturers
    In seeking to streamline the certification process for clean
alternative fuel conversion manufacturer, EPA proposes to allow
conversion manufacturers to combine several OEM test groups into larger
conversion test groups, where the regulatory requirements of 40 CFR
86.1827-01 and 86.1820-01 are still satisfied. Test groups cannot span
multiple durability groups.\58\ However, all clean alternative fuel
conversion manufacturers who meet the Small Volume Manufacturer
criteria in 40 CFR 86.1838-01 are eligible to use EPA assigned
deterioration factors.\59\ By default the assigned deterioration
factors define the durability group. As such, EPA proposes to use
select criteria in the durability group determination, 40 CFR 86.1820-
01, the test group determination, 40 CFR 86.1827-01, and other
additional criteria to allow OEM test groups to be combined into a
single clean alternative fuel conversion test group.
---------------------------------------------------------------------------

    \58\ 40 CFR 86.1827-01.
    \59\ 40 CFR 86.1826-01.
---------------------------------------------------------------------------

    Vehicles can be placed into the same clean alternative fuel
conversion test group using good engineering judgment if they satisfy
the following: \60\
---------------------------------------------------------------------------

    \60\ Of the criteria listed above, 4-6 are
from 40 CFR 86.1827-01(a) and 7-11 are from 40 CFR
86.1820-01. To provide flexibility in combining OEM test groups,
this proposal does not include the precious metal composition and
catalyst grouping statistic criteria in CFR 86.1820-01.
---------------------------------------------------------------------------

    (1) Same OEM and OEM model year \61\
---------------------------------------------------------------------------

    \61\ Aftermarket fuel conversion manufacturers would continue to
be able to use carry-over of test results from one model year to the
next if the OEM exercised such flexibility in accordance with EPA
regulations.
---------------------------------------------------------------------------

    (2) Same OBD group \62\
---------------------------------------------------------------------------

    \62\ On rare occasion, an OEM test group contains multiple OBD
groups. When this occurs, EPA proposes to allow the conversion test
group to include the multiple OBD groups that are covered by the OEM
test group.
---------------------------------------------------------------------------

    (3) Same vehicle classification (e.g. light-duty vehicle, heavy-
duty vehicle)
    (4) Engine displacement is within 15% of largest displacement or 50
CID, whichever is larger
    (5) Same number of cylinders or combustion chambers
    (6) Same arrangement of cylinders or combustion chambers (e.g. in-
line, v-shaped)
    (7) Same combustion cycle (e.g., two stroke, four stroke, Otto-
cycle, diesel-cycle)
    (8) Same engine type (e.g. piston, rotary, turbine, air cooled
versus water cooled)
    (9) Same OEM fuel type (except otherwise similar gasoline and E85
flex fuel vehicles may be combined into dedicated alternative fuel
vehicles)
    (10) Same fuel metering system (e.g. throttle body injection vs.
port injection)
    (11) Same catalyst construction (e.g. beads or monolith, metal vs.
ceramic substrate)
    (12) All converted vehicles are subject to the most stringent
emission standards used in certifying the OEM test groups within the
conversion test group
    EPA requests comment on the proposed conversion test group criteria
and what additional criteria, if any, should be considered to
adequately ensure that models within a conversion test group share
emissions characteristics that would be similarly affected by the
conversion system being certified. EPA also requests comment on whether
the data generated from a worst case EDV will adequately represent the
proposed allowable fuel conversion test groups.
a. Dual-Fuel Vehicle Carry-Across Procedures for Small Volume
Manufacturers
    As described in Section III.G.1.c, dual-fuel vehicles cannot be
certified to different standards for each fuel. However, if the
vehicles would otherwise meet the test group criteria described above,
the exhaust emissions test data for the new, alternative fuel from
dual-fueled emission data vehicles could be carried across to vehicles
which otherwise meet the test group criteria above. Test data can only
be carried across if the data demonstrate compliance with the most
stringent standard among the vehicles to which it is being applied.
This means that for dual-fuel conversions a manufacturer would have to
apply for multiple certificates if the OEM vehicles in the proposed
test group combination were originally certified to different
standards; however, the data acquired on the alternative fuel may be
applicable to multiple certificates when the test group criteria above
are otherwise met and the data demonstrate that the most stringent
standard within the group is met.
ii. Large Volume Manufacturers
    Large volume manufacturers must create test groups according to the
regulations in 40 CFR 86.1827-01. As required by these regulations, the
manufacturer must first create durability groups pursuant to 40 CFR
86.1820-01, and then divide those groups into test groups for the
purposes of exhaust emissions testing.
b. Engine Families for Heavy-Duty Engines
i. Small Volume Manufacturers
    In seeking to streamline the certification process and maintain
consistency with the policy for light-duty vehicles, EPA proposes to
allow combinations of several original OEM engine families into larger
conversion engine families. Engines can be placed into the same clean
alternative fuel conversion engine family using good engineering
judgment if they satisfy the following: \63\
---------------------------------------------------------------------------

    \63\ These proposed criteria are consistent with the 2009
guidance letter, CISD 09-14, which can be accessed electronically at
http://iaspub.epa.gov/otaqpub/display_file.jsp?docid=20194&flag=1.
---------------------------------------------------------------------------

    (1) Same OEM
    (2) Same OBD group after 2013

    (3) Same service class (e.g. light heavy-duty diesel engines,
medium heavy-duty diesel engines, heavy heavy-duty diesel engines)
    (4) Engine displacements is within 15% of largest displacement or
50 CID, whichever is larger
    (5) Same number of cylinders
    (6) Same arrangement of cylinders
    (7) Same combustion cycle
    (8) Same method of air aspiration
    (9) Same fuel type (e.g. diesel/gasoline)
    (10) Same fuel metering system (e.g., mechanical direct or
electronic direct injection)
    (11) Same catalyst/filter construction (e.g., metal vs. ceramic
substrate)
    (12) All converted vehicles are subject to the most stringent
emission standards. For example, 2005 and 2007 heavy-duty diesel
engines may be in the same family if they meet the most stringent
(2007) standards
    (13) Same emission control technology (e.g., internal or external
EGR)
a. Dual-Fuel Engine Carry-Across
    Heavy-duty dual-fuel engines cannot be certified to different
standards for each fuel.\64\ However, if the engines would otherwise
meet the engine family criteria described above, the exhaust emissions
test data for the new, alternative fuel from dual-fueled test engines
could be carried across to engines which otherwise meet the engine
family criteria above. Test data can only be carried across if the data
demonstrates compliance with the most stringent standard among the
engines to which it is being applied. This means that for dual-fuel
conversions, a manufacturer would have to apply for multiple engine
family certificates if the OEM engines in the proposed engine family
combination were originally certified to different standards; however,
the data acquired on the alternative fuel may be applicable to multiple
certificates when the engine family criteria above are otherwise met
and the data demonstrates that the most stringent standard within the
conversion engine family is met.
---------------------------------------------------------------------------

    \64\ See Section III.G.1.c.
---------------------------------------------------------------------------

ii. Large Volume Manufacturers
    All large volume heavy-duty engine manufacturers must create engine
families as set forth in 40 CFR 86.001-24.
c. Evaporative/Refueling Families
    Conversion manufacturers would be required to follow the regulatory
provisions for designating evaporative and refueling families. These
provisions are located in 40 CFR 86.1821-01 for light-duty vehicles and
heavy-duty complete vehicles and in 40 CFR 86.096-24(a)(12)-(13) for
heavy-duty engines. If the clean alternative fuel conversion system
continues to use the OEM evaporative/refueling emissions system in
their original configurations, the conversion evaporative/refueling
families will remain identical to the OEM evaporative/refueling
families. If, however, the conversion requires a new evaporative/
refueling system (as for pressurized fuels, such as CNG and LPG), then
the conversion manufacturer may create a single evaporative/refueling
family as long as the regulatory criteria for evaporative/refueling
families are met. Small volume manufacturers may use EPA assigned
evaporative/refueling deterioration factors in lieu of evaporative/
refueling durability demonstrations.
    Clean alternative fuel conversion evaporative families for dual-
fueled vehicles and engines may not include vehicles and engines which
were originally certified to different evaporative emissions standards.
3. Certification Demonstration Requirements
    EPA proposes that certification for clean alternative fuel
conversions be based on the certification procedures specified in 40
CFR part 86, subpart A, B and/or S and 40 CFR part 1065 as applicable,
subject to the exceptions and special provisions described in Section
III.G.1.a and Section V, if applicable.
a. Exhaust Emissions
i. Light-Duty and Heavy-Duty Complete Vehicles
    The exhaust emissions testing demonstration for light-duty and
heavy-duty complete vehicles would be conducted on a test group basis.
The worst-case emission data vehicle from each test group would be used
to demonstrate compliance with the most stringent standards represented
among the OEM vehicles when they were originally certified. All exhaust
certification requirements and test procedures which are required in
regulations for OEM certification would be required for fuel conversion
certification. Test procedures and certification requirements are
currently located in 40 CFR part 86, subparts B and S.
    The certification test procedures for conventionally-fueled
vehicles include test cycles designed to represent a variety of ``real
world'' driving conditions. One of these, the US06 test procedure and
drive cycle, is intended to emulate high speeds, aggressive
accelerations, and other typical driving patterns not captured by the
FTP (Federal Test Procedure). The US06 drive cycle is required for
conventionally-fueled vehicles, but alternative fuel vehicles were
excepted from the current regulations.\65\ It has been suggested that
the US06 exhaust emissions test is valuable for confirming catalyst
protection when vehicle operation results in high exhaust temperatures.
EPA seeks comment about the need to add a US06 demonstration or
statement of compliance with the US06 standard to the exhaust
certification demonstration requirement for clean alternative fueled
vehicle conversions.
---------------------------------------------------------------------------

    \65\ 61 FR 54871 (Oct. 22, 1996).
---------------------------------------------------------------------------

ii. Heavy-Duty Engines
    The exhaust emissions testing demonstration for heavy-duty engines
would be conducted on an engine family basis. The worst-case emission
data engine from each engine family would be used to demonstrate
compliance with the most stringent standards represented among the OEM
engines when they were originally certified. All exhaust certification
requirements and test procedures which are required in regulations for
OEM certification would be required for fuel conversion certification.
Test procedures and certification requirements are currently located in
40 CFR part 86 and part 1065.
b. Evaporative/Refueling Emissions
    EPA proposes to retain the evaporative and refueling emissions test
procedures and requirements promulgated in 40 CFR part 86 and part 1065
as the demonstration requirement for clean fuel conversion
certification. Please see the technical amendments discussed in Section
V for fuel-specific amendments that apply to conversions to CNG (or
LNG), LPG, or hydrogen fuels.
c. Durability Demonstration and Assigned Deterioration Factors
i. Small Volume Manufacturer Assigned Deterioration Factors
a. Light-Duty and Heavy-Duty Complete Vehicles
    As noted in Section III.H.2 above, small volume light-duty and
heavy-duty complete vehicle manufacturers and eligible small volume
test groups are permitted to use EPA-assigned deterioration factors in
lieu of exhaust and evaporative/refueling durability

demonstrations. If the emission data vehicle (EDV) has accrued more
than 10,000 miles, we propose to allow the conversion manufacturer to
utilize the scaled assigned deterioration factors described in Section
IV.B.3.c below.\66\
---------------------------------------------------------------------------

    \66\ This is due in part to the Fuel Economy testing
requirements which effectively limit the testing of vehicles with
more than 10,000 miles.
---------------------------------------------------------------------------

b. Heavy-Duty Engines
    For consistency with light-duty vehicles, EPA also proposes that
heavy-duty engine manufacturers who are eligible to use EPA assigned
deterioration factors would be permitted to use scaled assigned
deterioration factors when the emission data engine has accrued more
than 10,000 miles.
ii. Large Volume Manufacturer Durability Procedures
    Large volume manufacturers would be required to conduct all
applicable durability testing demonstrations.
d. On-Board Diagnostics
    EPA believes that a fully functional OBD system is valuable in
sustaining long-term emissions control and therefore proposes that the
same OBD requirements that apply to OEMs would continue to apply to
clean alternative fuel conversion systems. The certification
demonstration would require a submission of emissions data to prove
that the OBD continues to function and the Malfunction Indicator Light
(MIL) illuminates at the proper thresholds as set forth in 40 CFR
86.1806-01, 86.1806-04, and 86.1806-05 for light-duty vehicles and
heavy-duty complete vehicles. EPA also proposes that if an OEM heavy-
duty engine was certified with an OBD requirement, the conversion
should follow those requirements, unless an alternative fuel OBD
requirement is otherwise excepted from the OBD regulations. Heavy-duty
engine OBD requirements are promulgated in 40 CFR 86.007-17, 86.007-30,
86.010-18, and 86.010-38.
4. Certification Notification Process
    EPA proposes a conversion certification notification process based
on the OEM certification procedures specified in 40 CFR part 86, as
applicable. The proposed notification requirement is intended to
continue to incorporate the entire OEM certification process. If the
OEM process is amended in the future, the fuel conversion certification
procedures would also change, unless specifically excepted. The
following is a brief overview of the current light-duty and heavy-duty
complete vehicle certification process, but should not be considered an
exhaustive list of all certification requirements:
    1. Manufacturer requests an EPA manufacturer code and creates a
data entry (Verify) account. Instructions for this are located at
http://www.epa.gov/otaq/verify/mfr-code.htm. Manufacturers are assigned
an EPA certification representative.
    2. Manufacturer contacts their assigned EPA certification
representative to describe the certification plan, including a
discussion on how emissions durability will be demonstrated.
    3. Manufacturer conducts all testing, including exhaust emission
testing, evaporative/refueling emission testing, and on-board
diagnostics demonstrations.
    4. Manufacturer enters data in web-based data entry system (Verify)
and fills out a confirmatory testing waiver request to request a place
in the EPA confirmatory testing queue.
    5. EPA conducts confirmatory testing based on the need to test the
first vehicle from a new manufacturer, a random selection of an
emission data vehicle through the computerized Verify system, the
desire to test a vehicle employing new technology, or other EPA reasons
as appropriate.
    6. Certification fees are paid to EPA. Reduced fees may be
available. See http://www.epa.gov/otaq/guidance.htm for instructions
and forms pertaining to fee payment.
    7. Manufacturer submits an application for certification according
to 40 CFR 86.1843-01 and 86.1844-01. The application must contain any
applicable statements of compliance or attestations \67\ and an OBD
approval letter from the California Air Resources Board or an EPA OBD
approval letter if the vehicle will be sold only in States which have
not adopted the California emissions standards.
---------------------------------------------------------------------------

    \67\ The certification process may permit several statements of
compliance or attestations in lieu of test data. Some of these are
found in the OEM certification regulations in 40 CFR part 86,
subparts A and S and 40 CFR part 1065. In addition we are proposing
attestation statements specific to conversion to a clean alternative
fuel. These would include:
    1. The test group or engine family converted to dual fuel
operation retains all the OEM fuel system, engine calibration, and
emission control system functionality when operating on the fuel
with which the vehicle was originally certified.
    2. The test group or engine family converted to dual fuel
operation retains all the functionality of the OEM OBD system (if so
equipped) when operating on the fuel with which the vehicle was
originally certified.
    3. The test group or engine family converted to dual fuel
operation properly purges hydrocarbon vapor from the evaporative
emission canister when the vehicles/engines are operating on the
alternative fuel.
    4. The test group or engine family converted to an alternative
fuel has fully functional OBD systems (if the OEM vehicles or
engines are OBD equipped) and therefore meet the OBD requirements in
40 CFR Part 86, subpart S or subpart A, as appropriate, when
operating on the alternative fuel.
---------------------------------------------------------------------------

    8. If EPA testing confirms that all standards are met, based on
testing at the EPA NVFEL laboratory, or based on a review of the data
submitted by the manufacturer if no EPA confirmatory testing is
conducted, a Certificate of Conformity is issued to the manufacturer
for the appropriate fuel conversion test group and evaporative
emissions family of vehicles. The certificate is valid until December
31st of the model year on the certificate.
a. Re-Certification
    Conversion manufacturers who wish to renew a certificate that has
expired may re-certify the same conversion group in subsequent years
using the same data. To re-certify, the manufacturer would update the
cover page of the application, re-enter the necessary data into EPA's
on-line data submission Web site, and submit the certification fees.
5. In-Use Compliance
    Clean alternative fuel conversion manufacturers are subject to in-
use requirements. Many of these are described in Section III above,
including warranty, defect reporting and recall requirements, as well
as EPA's authority to perform in-use testing.

B. Intermediate Age Vehicle and Engine Compliance Program

    EPA is proposing an alternative to certification to satisfy the
compliance demonstration and notification requirements for vehicles and
engines that are no longer new but still fall within their useful
life.\68\ The intermediate age vehicle and engine compliance program
(intermediate age program) would require conversion manufacturers to
demonstrate through testing that the converted vehicle or engine will
continue to meet applicable standards through its useful life.
Alternatively, to qualify for an exemption to the tampering
prohibition, manufacturers could opt to certify conversion systems for
intermediate age vehicles and engines as if they were new vehicles and
engines. See Section IV.A.
---------------------------------------------------------------------------

    \68\ The original subpart F rulemaking weighed several options
for useful life determination of a fuel converted vehicle or engine,
and it was determined that the useful life of the original vehicle
or engine would not be extended after fuel conversion. 59 FR 48488.
This proposal leaves this determination unchanged.

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

    The proposal to create an alternative to certification for
intermediate age vehicle and engine conversion systems addresses EPA's
interest in creating a streamlined compliance process that is
appropriate for vehicles and engines that have been subject to real-
world aging. EPA does not believe certification of intermediate age
vehicles and engines is necessary because they are generally no longer
representative of certification vehicles, as described in 40 CFR part
86, subpart S. EPA originally developed the certification test
procedures for new OEM vehicles and engines. Typical OEM vehicles
delivered to EPA for confirmatory testing are recently manufactured
pre-production models with about 4,000 miles of engine and emission
control system stabilization mileage. No OEM vehicles with more than
10,000 miles are tested for certification.\69\
---------------------------------------------------------------------------

    \69\ This is due in part to fuel economy testing regulations
which limit the accrued mileage for a fuel economy test vehicle to
10,000 miles. 40 CFR 600.007-08(b)(1).
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    The proposed program for intermediate age vehicles and engines
maintains many of the existing certification test procedures, but
departs from the existing subpart F requirements in several notable
areas. The demonstration of compliance with applicable standards would
use the same procedures required of certified conversion manufacturers
for exhaust and evaporative emissions testing.\70\ However, the OBD
demonstration requirement would be significantly different. Instead of
requiring OBD demonstration testing as required for certification, an
attestation that the OBD system is fully functional would be required
to meet the OBD demonstration requirement for conversion of an
intermediate age vehicle or engine.\71\ The notification process would
also be significantly different for intermediate age vehicles and
engines. Conversion manufacturers would still submit test data,
attestations, and other required information to EPA; however the
application process would be significantly streamlined. Certification
fees would not be assessed unless EPA updates its fees rule in the
future.\72\ Conversion manufacturers participating in the intermediate
age program would not receive a certificate of conformity. Rather, EPA
would maintain a publicly available list identifying conversion systems
that have satisfied the intermediate age demonstration and notification
requirements, and that therefore have qualified for the tampering
exemption.
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    \70\ The technical amendment proposals described in Section V
and the proposed scaling of assigned deterioration factors described
in section IV.B.3.c.i would be available.
    \71\ See Section IV.B.4 for more information about the required
OBD attestations.
    \72\ CFR part 1027.
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1. Applicability
    Vehicles and engines would become eligible for the intermediate age
compliance program when the date of their conversion is in a calendar
year that is at least two years after the original model year of the
vehicle or engine, i.e. when they are about two years old. For example,
in calendar year 2010, model year 2008 and earlier vehicles and engines
would be eligible for the intermediate age program.
    EPA proposes that manufacturers of conversion systems for vehicles
and engines that are outside their full useful life may also use the
intermediate age program as a demonstration sufficient to qualify for
the clean alternative fuel conversion exemption from tampering.
Conversion manufacturers that choose to participate in the intermediate
age program would need to demonstrate compliance with the full useful
life standards, even if the vehicle or engine has surpassed its useful
life in age or mileage. In that case it would not be required to
generate or use deterioration factors.
2. Test Groups/Engine Families and Evaporative/Refueling Families
a. Test Groups for Light-Duty and Heavy-Duty Complete Vehicles
i. Small Volume Manufacturer Test Groups
    EPA proposes that small volume manufacturers of conversion systems
for intermediate age vehicles be permitted some additional flexibility
in creating test groups to which the conversion is applicable. The
primary difference between proposed test group criteria for the new and
intermediate age programs is the elimination of the OBD group criterion
under the intermediate age program. Vehicles can be placed into the
same clean alternative fuel conversion test group using good
engineering judgment if they satisfy the following:
    (1) Same OEM and OEM model year \73\
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    \73\ Aftermarket fuel converters are currently permitted to use
carry-over of test results from one model year to the next if the
OEM exercised such flexibility in accordance with EPA regulations.
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    (2) OBD still functional \74\
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    \74\ Note that a functional OBD system means that it must not be
disabled, there are no false MILs or false DTCs, and all readiness
flags must be set.
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    (3) Same vehicle classification (e.g., light-duty vehicle, heavy-
duty vehicle)
    (4) Engine displacement (within 15% of largest displacement or 50
CID, whichever is larger)
    (5) Same number of cylinders or combustion chambers
    (6) Same arrangement of cylinders or combustion chambers (e.g., in-
line, v-shaped)
    (7) Same combustion cycle (e.g., two stroke, four stroke, Otto-
cycle, diesel-cycle)
    (8) Same engine type (e.g., piston, rotary, turbine, air cooled
versus water cooled)
    (9) Same OEM fuel type (except otherwise similar gasoline and E85
flex fuel vehicles may be combined into dedicated alternative fuel
vehicles)
    (10) Same fuel metering system (e.g., throttle body injection vs.
port injection)
    (11) Same catalyst construction (e.g., beads or monolith, metal vs.
ceramic substrate)
    (12) All converted vehicles are subject to the most stringent
emission standards used in certifying the OEM test groups within the
conversion test group
    EPA especially seeks comment regarding whether the 15% engine
displacement criterion should apply to intermediate age vehicles and
engines. EPA seeks comment on allowing additional flexibility by
permitting combinations of vehicles based on any other criteria. EPA
would like to receive relevant data supporting any combination
suggestions.
ii. Large Volume Manufacturers
    EPA proposes to allow large volume manufacturers the same test
group combination flexibility as small volume manufacturers when
designating intermediate age vehicle test groups. See Section
IV.B.2.a.i for details. However, large volume manufacturers are
required to conduct durability testing, as noted below.
iii. Dual-Fuel Vehicle Carry-Across
    Under the proposed rule, dual-fuel vehicles which have different
standards would need to create a separate submission to EPA for each
OEM test group with different standards. However, as is described above
in Section IV.A.2.a.i.a, test data from an emission data vehicle on the
alternative fuel may be used to satisfy the demonstration requirement
of multiple OEM test groups if the conversion test group criteria
described above are otherwise met and the data demonstrate compliance
with each standard.

b. Engine Families for Heavy-Duty Engines
i. Small Volume Manufacturers
    EPA proposes to allow the same engine family combination criteria
that are described in Section IV.A.2.b.i for clean alternative fuel
conversion of new engines.
ii. Large Volume Manufacturers
    EPA proposes to allow large volume manufacturers the same
flexibility as small volume manufacturers when designating intermediate
age heavy-duty engine families. See Section IV.B.2.b.i for details.
However, large volume manufacturers are required to conduct durability
testing.
iii. Dual-Fuel Engine Carry-Across
    EPA proposes to allow the same data carry-across procedures for
intermediate age dual-fuel engines described in Section IV.A.2.b.i.a.
c. Evaporative/Refueling Families
    EPA proposes that evaporative family criteria under the
intermediate age program remain as provided in 40 CFR part 86. If the
OEM evaporative system is no longer functionally necessary (e.g.,
conversion to dedicated CNG or LPG), then conversion manufacturers may
create new evaporative conversion groups following the criteria in 40
CFR 86.1821-01 for light-duty and heavy-duty complete vehicles and 40
CFR 86.096-24(a)(12)-(13) for heavy-duty engines. Clean alternative
fuel conversion evaporative/refueling families for dual-fueled vehicles
cannot include vehicles that were originally certified to different
evaporative emissions standards.
3. Demonstration Requirements
    EPA proposes that the demonstration requirements for clean
alternative fuel conversions be based on the certification procedures
specified in 40 CFR part 86, subparts A, B and/or S and 40 CFR part
1065 as applicable, subject to the exceptions and special provisions
described in this section, Section III.G.1.a and Section V, if
applicable.
a. Exhaust Emissions
    Exhaust emissions testing demonstration is conducted on a test
group (light-duty) or engine family (heavy-duty) basis. The worst-case
emission data vehicle or engine from each test group or engine family
would be used to demonstrate compliance with the most stringent
standards represented among the OEM vehicle or engines when they were
originally certified. All exhaust demonstration requirements and test
procedures which are required in regulations for OEM certification
would be required for fuel conversion compliance. Test procedures and
other requirements are currently located in 40 CFR part 86, subparts A,
B, C, O, P, S and 40 CFR part 1065.
b. Evaporative/Refueling Emissions
    The acceptable test procedures to demonstrate that a vehicle or
engine will meet evaporative standards during normal vehicle operation,
including refueling, are specified in 40 CFR part 86 and part 1065. EPA
proposes that these test procedures and other requirements continue to
apply for the intermediate age vehicle and engine fuel conversion
program. Please see the technical amendments discussed in Section V for
fuel-specific amendments which apply to conversions to CNG (or LNG) and
LPG or hydrogen fuels.
c. Durability Demonstration and Assigned Deterioration Factors
i. Small Volume Manufacturers
    As noted in Section III.H.2 above, small volume manufacturers and
eligible small volume test groups are permitted to use EPA-assigned
deterioration factors in lieu of exhaust and evaporative/refueling
durability demonstrations. EPA proposes to continue this practice for
purposes of evaluating conversion systems that will be applied to
intermediate age vehicles and engines. In addition, EPA is proposing a
new concept which would be applicable to emissions data vehicles and
engines with more than 10,000 miles. EPA proposes to allow small volume
manufacturers to use ``scaled deterioration factors.'' Scaled
deterioration factors would be derived using current assigned
deterioration factors to determine mileage applicable deterioration
factors from 10,000 miles through intermediate useful life and from
intermediate useful life through full useful life.\75\ Although the
actual rates of emissions deterioration from 10,000 miles to
intermediate useful life and from intermediate useful life to full
useful life may vary, EPA may assume a linear increase of emissions
with increasing mileage in order to facilitate a simple scaling of the
EPA-assigned deterioration factors. In the future, EPA may adjust these
scaled assigned deterioration factors if we find the rate of
deterioration non-constant or the rate differs by fuel type.
Mathematically, a constant rate of deterioration can be expressed as:
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    \75\ Intermediate standards only apply to those vehicles
originally certified with intermediate standards.
[GRAPHIC] [TIFF OMITTED] TP26MY10.000

    Note: This does not mean that the deterioration factor increases
linearly with mileage. The equation assumes that the grams of
pollutant per mile increases at a constant rate as vehicle mileage
---------------------------------------------------------------------------
increases.

    In addition to this primary assumption, EPA proposes to use these
two definitions:
[GRAPHIC] [TIFF OMITTED] TP26MY10.001

[GRAPHIC] [TIFF OMITTED] TP26MY10.002

Where:

ADF(FUL) is the full useful life assigned multiplicative
deterioration factor (DF).
FULgpm is the grams per mile of pollutant projected at full useful
life.
INITgpm is the grams per mile of pollutant measured at the beginning
of the vehicle or engine's useful life.
SDF(FUL) is the scaled full useful life multiplicative DF.
MGgpm is the grams per mile of pollutant at the actual mileage of
emission data vehicle or engine.

    Based on the assumption in equation 1:
    [GRAPHIC] [TIFF OMITTED] TP26MY10.003

Where:

FULMG is the appropriate full useful life mileage.
MG is the actual mileage of the emission data vehicle or engine.
INITMG is the mileage at the beginning of the useful life. Note that
this value is zero for heavy-duty vehicles, since evaluation is done
at the zero-hour level.

    From this expression, equations 2 and 3 can be used to ultimately
arrive at:
[GRAPHIC] [TIFF OMITTED] TP26MY10.004

    This equation shows how the scaled full useful life multiplicative
DF can be calculated using the emissions data vehicle or engine mileage
and the assigned full useful life multiplicative DF.
    By carrying out the same processes, scaled intermediate useful life
of deterioration factors, where applicable, can be determined by the
expression:
[GRAPHIC] [TIFF OMITTED] TP26MY10.005

Where:

SDF(MID) is the scaled intermediate useful life multiplicative DF.
MIDMG is the intermediate useful life mileage.
ADF(MID) is the intermediate useful life assigned multiplicative DF,
where applicable.

    In the same manner, additive scaled deterioration factors could
also be derived. The resulting equations are:
[GRAPHIC] [TIFF OMITTED] TP26MY10.006

Where:

ODF is the OEM's original additive DF and ASDF is the additive
scaled deterioration factor.

    EPA proposes using equations 4, 5 and 6 to scale deterioration
factors of vehicles with more than 10,000 miles used in the testing of
clean alternative fuel conversions, for demonstration of compliance
with exhaust and evaporative/refueling emissions standards. Only the
derivation of the full useful life scaled additive deterioration factor
is presented. However, the derivation of the intermediate useful life
scaled additive deterioration factor would follow the same process.
ii. Large Volume Manufacturer Durability Procedures
a. Light-Duty and Heavy-Duty Complete Vehicles
    Durability testing would be required for large volume manufacturers
of clean alternative fuel conversions of intermediate age vehicles. EPA
proposes that durability groups for intermediate age vehicles would be
designated using the provisions set forth in 40 CFR 86.1820-01, except
the durability grouping criteria for intermediate age vehicles need not
include the precious metal composition and catalyst grouping statistic
criteria, since they are not included in the test group criteria for
clean alternative fuel conversions.
b. Heavy-Duty Engines
    Durability testing would be required for large volume manufacturers
of clean alternative fuel conversions for intermediate age engines.
d. On-Board Diagnostics
    EPA believes the proper functioning of an OBD system is essential