# Transportation Conformity Rule Amendments: Flexibility and Streamlining

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A97-20968

## Record

- **Collection:** Federal Register
- **Document type:** Rule
- **Published:** August 15, 1997
- **Citation:** 62 FR 43780

## Text

SUMMARY: Today EPA promulgates a clarified and more flexible
transportation conformity rule. The conformity rule requires that
transportation plans, programs, and projects conform to state air
quality implementation plans (SIPs) and establishes the criteria and
procedures for determining whether or not they do. Conformity to a SIP
means that transportation activities will not produce new air quality
violations, worsen existing violations, or delay timely attainment of
the national ambient air quality standards.
The conformity rule changes promulgated today result from the
experience that EPA, the Department of Transportation (DOT), and state
and local air and transportation officials have had with implementation
of the rule since it was first published in November of 1993. While
these changes clarify the rule and in some cases offer increased
flexibility, they will not result in any negative change in health and
environmental benefits.
Today's rule gives state and local governments more authority in
selecting the performance measures used as tests of conformity and more
discretion when a transportation plan does not conform to a SIP. For
example, the rule allows motor vehicle emissions budgets in a submitted
SIP to be used to determine conformity instead of the ``build/no-
build'' test, and rural areas can choose among several conformity tests
to address the time period after that covered by the SIP.

EFFECTIVE DATE: September 15, 1997.

ADDRESSES: Materials relevant to this rulemaking are contained in
Docket No. A-96-05. The docket is located in room M-1500 Waterside Mall
(ground floor) at the Environmental Protection Agency, 401 M Street
SW., Washington, DC 20460. The docket may be inspected from 8 a.m. to
5:30 p.m., Monday through Friday, including all non-government
holidays. For information on electronic availability see Supplementary
Information.

FOR FURTHER INFORMATION CONTACT: Meg Patulski, Transportation and
Market Incentives Group, Regional and State Programs Division, U.S.
Environmental Protection Agency, 2565 Plymouth Road, Ann Arbor, MI
48105, [email protected]. (313) 741-7842.

SUPPLEMENTARY INFORMATION:

Regulated Entities

Entities potentially regulated by the conformity rule are those
which adopt, approve, or fund transportation plans, programs, or
projects under title 23 U.S.C. or title 49 U.S.C. Regulated categories
and entities include:

------------------------------------------------------------------------
Examples of regulated
Category entities
------------------------------------------------------------------------
Local government.......................... Local transportation and air
quality agencies.
State government.......................... State transportation and air
quality agencies.
Federal government........................ Department of Transportation
(Federal Highway
Administration and Federal
Transit Administration).
------------------------------------------------------------------------

This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by this
rule. This table lists the types of entities that EPA is now aware
could potentially be regulated by the conformity rule. Other types of
entities not listed in the table could also be regulated. To determine
whether your organization is regulated by this action, you should
carefully examine the applicability requirements in Sec. 93.102 of the
conformity rule. If you have questions regarding the applicability of
this action to a particular entity, consult the person listed in the
preceding FOR FURTHER INFORMATION CONTACT section.

Electronic Availability

The final rule is also available electronically from the EPA
internet web site. Users are able to access and download files on their
first call using a personal computer according to the following
information:

Internet Web Sites

http://www.epa.gov/docs/fedrgstr/EPA-AIR/
(either select desired date or use Search feature)
Or
http://www.epa.gov/OMSWWW/
(look in What's New or under the Conformity file area)

The electronic version of this final rule should be available today on
any of the above-listed sites. Please note that due to differences
between the software used to develop the document and the software into
which the document may be downloaded, changes in format, page length,
etc. may occur.
The contents of this preamble are listed in the following outline:

I. Background on Transportation Conformity
II. Replacement of Build/No-build Test With Submitted SIPs
III. Other Comments on Conformity Tests
IV. Conformity Tests for Areas That Are Not Required to Submit SIPs
V. Rural Nonattainment and Maintenance Areas
VI. Mismatch in SIP/Transportation Plan Timeframe
VII. Non-federal Projects
VIII. Deadline for Use of Network Models and Affected Areas
IX. Content of Network Modeling Requirements in Serious and Above
Ozone and CO Areas
X. Adding Non-Exempt Projects to the Plan/TIP Without Regional
Analysis
XI. Consequences of SIP Disapproval
XII. Traffic Signal Synchronization
XIII. Conformity SIPs
XIV. Hot-spot Tests
XV. TCM Flexibility
XVI. Conformity and the Proposed NAAQS Revisions
XVII. Minor Changes to the Rule
XVIII. Administrative Requirements

I. Background on Transportation Conformity

Today's action amends the transportation conformity rule,
``Criteria and Procedures for Determining Conformity to State or
Federal Implementation Plans of Transportation Plans, Programs, and
Projects Funded or Approved Under Title 23 U.S.C. or the Federal
Transit Act'' (58 FR 62188, November 24, 1993). Required under section
176(c) of the Clean Air Act as amended in 1990, the transportation
conformity rule established the criteria and procedures by which the
Federal Highway Administration (FHWA), the Federal Transit
Administration (FTA), and metropolitan planning organizations (MPOs)
determine the conformity of federally funded or approved highway and
transit plans, programs, and projects to state air quality
implementation plans (SIPs). Conformity ensures that transportation
plans, programs, and projects do not produce new air quality
violations, worsen existing violations, or delay timely attainment of
national ambient air quality standards (NAAQS). According to the Clean
Air Act, federally supported activities must conform to the
implementation plan's

[[Page 43781]]

purpose of attaining and maintaining these standards.
Since publication of the transportation conformity rule in November
1993, EPA, the Department of Transportation (DOT), and state and local
air and transportation officials have had considerable experience
implementing the criteria and procedures in the rule. This experience
has led to the streamlining, clarification, and new opportunities for
flexibility found in today's rule, which is the third of a series of
amendments to the transportation conformity rule. In each case, the
amendments were needed to clarify ambiguities, correct errors, or make
the conformity process more logical and feasible.
The first set of amendments was published as an interim final rule
on February 8, 1995 (60 FR 7449), and was finalized on August 7, 1995
(60 FR 40098). The first set of amendments aligned the dates of
conformity lapses (i.e., halting conformity determinations for new
federally funded highway/transit projects) due to SIP failures with the
application of Clean Air Act highway sanctions for certain ozone areas
and all areas with disapproved SIPs with a protective finding (defined
below in section XI.).
The second set of amendments was proposed on August 29, 1995 (60 FR
44790), and was finalized on November 14, 1995 (60 FR 57179). The
second set of amendments aligned the date of conformity lapses with the
date of application of Clean Air Act highway sanctions for any failure
to submit or submission of an incomplete control strategy SIP; extended
the grace period before which areas must determine conformity to a
submitted control strategy SIP; established a grace period before which
transportation plan and program conformity must be determined in newly
designated nonattainment areas; and corrected the nitrogen oxides
(NOX) provisions of the transportation conformity rule to be
consistent with the NOX requirements of the Clean Air Act
and previous commitments made by EPA.
The second set of amendments also allowed any transportation
control measure (TCM) from an approved SIP to proceed during a
conformity lapse, although EPA stated that it did not intend to approve
SIPs containing TCMs that have not been coordinated through the
transportation planning process, as required by 23 CFR part 450 and 49
CFR part 613. The Clean Air Act and the Intermodal Surface
Transportation Efficiency Act require that an integrated
transportation/air quality planning process be used to identify
effective TCMs and ensure their funding sources.
The Notice of Proposed Rulemaking for today's rule was published in
the Federal Register on July 9, 1996 (61 FR 36111). This proposal was
undertaken in response to several issues raised by conformity
implementers and other interested parties. EPA worked closely with
conformity stakeholders in developing the proposal, and had input from
the National Governors' Association (NGA), the Environmental Council of
States (ECOS), state DOTs, state environmental agencies, MPOs,
environmentalists, industry groups, other public interest groups, and
DOT. In 1995, meetings to discuss potential amendments to the
conformity rule were held by NGA and ECOS as well as the EPA. EPA
developed draft regulatory language in response and sought comment from
stakeholders.
The proposal's comment period ended September 9, 1996. EPA held a
public hearing for this proposal on August 6, 1996. EPA received more
than 50 comments from a variety of interests, including MPOs, state and
local air quality agencies, state DOTs, NGA, and environmentalists.
Copies of comments in their entirety can be obtained from the docket
for this rule (see ADDRESSES). The docket also includes a complete
Response to Comments document for this rule.
Since 1993, the transportation conformity rule has been included in
40 CFR part 51 and largely duplicated in 40 CFR part 93. In order to
streamline the CFR and eliminate this duplication, the only section of
today's conformity rule that remains in 40 CFR part 51 is Sec. 51.390,
which requires a conformity SIP revision. Part 51 is entitled,
``Requirements for Preparation, Adoption, and Submittal of
Implementation Plans.'' The remainder of the conformity rule is
included in 40 CFR part 93, which is entitled, ``Determining Conformity
of Federal Actions to State or Federal Implementation Plans.''

II. Replacement of Build/No-Build Test With Submitted SIPs

A. Description of Final Rule

Today's action finalizes the proposal to eliminate the build/no-
build test and other emission reduction tests once a control strategy
SIP or maintenance plan has been submitted to EPA and EPA has had 45
days to review the SIP submission and the adequacy of its motor vehicle
emissions budget(s) for conformity purposes. This final rule also
includes regulatory text from the proposal's preamble which establishes
the minimum criteria that must be satisfied in order for EPA to find a
submitted motor vehicle emissions budget adequate for transportation
conformity purposes. EPA clarifies today that submitted SIPs must
already meet these minimum criteria in order to be approved; EPA is not
imposing any new requirements for submitted SIPs.
EPA described the minimum adequacy criteria in the preamble to the
proposal (61 FR 36114, July 9, 1996), and they are outlined as follows.
In accordance with this final rule, an area's submitted SIP must be
endorsed by the Governor (or his/her designee) and subject to a public
hearing in order for EPA to find the submitted SIP adequate. Prior to
submitting the SIP, consultation between federal, state, and local
agencies must occur. SIP development must be documented and any
technical support information needed to review the adequacy of the SIP
must be submitted to EPA. In addition, any concerns stated by EPA must
be addressed before the SIP is submitted. The emissions budget(s) must
be clearly identified and precisely quantified. When considered with
point, area, and mobile sources, the emissions budget(s) must be
consistent with applicable requirements for reasonable further progress
(RFP), attainment, or maintenance, depending upon the particular SIP
submission. The SIP budget(s) must be consistent with the area's
emissions inventory for all sources and a clear relationship among the
budget(s), control measures and emissions inventory must be shown.
In addition, submitted SIPs must explain and document any changes
to previously submitted motor vehicle emissions budgets and control
measures; impacts on point and area source emissions; any changes to
established safety margins; and reasons for the changes, including the
basis for any changes related to emission factors or estimates of
vehicle miles traveled (VMT). EPA is defining safety margin in this
final rule to be the amount by which the total projected emissions from
all sources of a given pollutant are less than the total emissions that
would satisfy the applicable Clean Air Act requirement for RFP,
attainment, or maintenance.
EPA will interpret these adequacy criteria to mean that if a
submitted SIP's emissions budgets rely upon additional control measures
to demonstrate RFP, attainment, or maintenance, such new control
measures must be specified in the SIP submission. The submitted SIP
would need to quantify the emissions impacts of any new control
measures in its revised SIP, and at a minimum,

[[Page 43782]]

include commitments by appropriate agencies for adoption and
implementation schedules, in addition to draft regulations or other
relevant documents. These are minimum criteria for adequacy of
emissions budgets for conformity purposes; an approvable SIP must have
adopted and enforceable control measures.
Prior to EPA determining the adequacy of a submitted SIP budget,
EPA will also review documentation from the state's public comment
hearing on the SIP submission and the state's responses to the public
comments received. This documentation is currently required to be
included in the SIP package when it is submitted to EPA for its review.
EPA will send a letter to the state documenting EPA's finding of
adequacy or inadequacy, including EPA's consideration of public
comment.
The conformity adequacy review is separate from EPA's completeness
review of a submitted SIP for purposes of SIP processing. In addition,
EPA's 45-day adequacy review should not be used to prejudge EPA's
ultimate approval or disapproval of the SIP. As stated in the proposal,
EPA cannot ensure that a submitted SIP is consistent with RFP,
attainment, or maintenance until EPA has completed its formal review
process and the SIP has been approved or disapproved through notice-
and-comment rulemaking. Although the minimum criteria for adequacy
allow EPA to make a cursory review of the submitted motor vehicle
emissions budget for conformity purposes, EPA recognizes that other
elements must also be in the SIP for it to ultimately be approved.
Therefore, a budget that is found adequate in the 45-day review period
could later be disapproved when reviewed with the entire SIP
submission.
EPA will find a submitted motor vehicle emissions budget inadequate
if the submitted budget does not meet the minimum criteria. However,
the criteria included in the conformity rule are not intended to be a
comprehensive definition of an adequate SIP for SIP approval purposes.
EPA also clarifies that the 45-day adequacy review period begins
upon the receipt of the SIP submission in the EPA regional office.
Areas that submit SIPs after the effective date of this final rule
will be able to use their SIP budget(s) within 45 days of submission or
sooner if EPA finds them adequate. Areas that submit SIPs prior to the
effective date of this final rule can use those SIPs according to the
requirements of Sec. 51.448(a)(2)/Sec. 93.128(a)(2) as amended on
November 14, 1995 (60 FR 57179). According to these sections, areas can
use submitted SIP budgets beginning 90 days after submission unless EPA
finds them inadequate; areas can use them earlier if EPA declares them
adequate.
EPA's 90-day review period that is described in Sec. 51.448(a)(2)/
Sec. 93.128(a)(2) of the previous conformity rule may have used
different standards for adequacy than are being outlined in this final
rule, because under the previous rule the build/no-build test applied
in addition to the submitted budget. SIPs that EPA believed adequate
under that rule may not be adequate if they are the sole test of
conformity. As a result, EPA may use the adequacy criteria of this
final rule to re-examine SIPs that were submitted before this final
rule and have not yet been approved. EPA intends to complete this re-
examination within 45 days after the effective date of this final rule.
During this time, areas will continue using their SIPs that have been
submitted for more than 90 days; EPA's possible re-examination will not
delay or in any way interfere with areas determining conformity unless
EPA finds the SIP inadequate.

B. Rationale and Response to Comments

Most commenters agreed that the emission reduction tests should not
be required once a SIP is submitted. The majority of commenters agreed
that compared to the budget test, the value of the build/no-build test
is limited. Commenters believed that the proposed flexibility would
streamline conformity and use state and local resources more
efficiently. Most commenters also supported the proposal's reduction of
the adequacy review period for a submitted SIP from 90 to 45 days.
However, some commenters were concerned that submitted budgets may
not be able to fully satisfy the purpose of the emission reduction
tests, which is to ensure that annual emissions will be reduced and/or
that violations will not be created or worsened (see Clean Air Act
sections 176(c)(3)(A)(iii) and (c)(1)(B)). Specifically, some
commenters stated that the proposed EPA review period would not be
sufficient to ensure the adequacy of submitted budgets because the
proposal did not establish any objective criteria for adequacy in the
regulatory language, or provide an opportunity for public comment on
EPA's adequacy finding. Some argued that the absence of adequacy
criteria for submitted budgets could lead to the submission of inflated
budgets (not based on credible, quantifiable attainment demonstrations)
for the convenience of determining conformity. Commenters felt that
although these SIPs would ultimately not prove acceptable, they could
allow projects to proceed during EPA's rulemaking to disapprove the
SIP. This could also lead to delays in attainment. Another commenter
was concerned that the lack of objective criteria for adequacy in the
rule would make EPA more vulnerable to political pressure to approve
inadequate budgets.
EPA agrees that if submitted budgets are to replace the build/no-
build test as the primary measure of conformity, the criteria by which
EPA will judge their adequacy must be clearly articulated in the rule.
EPA has done so in this final action, and these criteria are those
described in the preamble to the proposal. In addition, submitted SIPs
must already meet these criteria in order for EPA to ultimately approve
them. Since the criteria included in this final rule are the same as
those described in the proposal and thus subjected to public comment,
EPA does not believe a reproposal is necessary prior to adding the
criteria to the regulatory language.
EPA also agrees that the public should be given the opportunity to
comment on the adequacy of a submitted SIP. Some commenters suggested
requiring public notice of submitted budgets and a 60-day period during
which the public could file objections and present arguments to EPA for
its consideration in its adequacy review. However, because the state
already holds a public hearing on the draft SIP before submitting it to
EPA, EPA believes the public has sufficient opportunity to comment at
the state level on the adequacy of the budgets contained in the SIP.
EPA believes the rule now addresses commenters' concerns by requiring
EPA to review and consider the compilation of public comment that the
state is already required to include with any SIP submission. EPA will
document its consideration of such comments in the letter to the state
indicating the adequacy of the submitted budget(s).
Commenters also expressed concern that EPA is not even obligated to
determine adequacy, since a submitted budget can be used even if EPA
has not determined adequacy within the 45-day review period. However,
EPA is committed to helping ensure that conformity and future
transportation investment decisions are made using the best possible
SIPs, and EPA intends to review all submitted SIPs within the 45-day
period.
Some commenters stated that EPA may not establish a motor vehicle
emissions budget as a legally enforceable obligation without following
the notice and comment procedures of the Administrative

[[Page 43783]]

Procedure Act (APA). EPA believes that it is appropriate not to provide
notice and comment for adequacy determinations for submitted SIPs,
since these determinations are only administrative reviews and not
substantive rules. When EPA reviews a SIP for completeness, EPA does
not perform a notice-and-comment rulemaking. EPA believes that
determining adequacy is more similar to completeness review than a SIP
approval action, in that adequacy determinations are merely
administrative applications of established criteria to emissions
budgets. For these reasons, EPA is not requiring notice and comment for
its 45-day adequacy review period. However, EPA believes the
commenters' concerns relating to public review under the APA are
addressed because EPA has established the criteria for determining
adequacy through this final rule, which has gone through APA notice and
comment procedures. In addition, EPA is ensuring that public comment on
adequacy of individual budgets is considered through review of comments
submitted to the state.
In addition to specific criteria for adequacy, some commenters
wanted to limit the grandfathering of new projects found to conform on
the basis of a submitted SIP's budget. A ``grandfathered'' project can
proceed without further conformity determinations (see Sec. 93.102(c)
for more details). Transportation projects are currently grandfathered
after a National Environmental Policy Act (NEPA) document is approved
and a project-level conformity determination is made. In order for a
project-level conformity determination to occur, a conforming plan and
TIP must be in place at the time of the determination.
Under the commenters' scenario, projects would only be
grandfathered when a project agreement authorizing federal funds
pursuant to 23 USC 110 or 49 USC 5309 has been executed. This would
grandfather projects later in the transportation planning process than
is currently the case. Changing the grandfathering in this manner would
make it more likely that local and state planners could halt a
project(s) if the SIP is ultimately disapproved. The commenters were
concerned that a submitted SIP's budget may not contain the necessary
emission reductions for demonstrating conformity in the future. If EPA
declared a budget adequate during the 45-day review period but later
disapproved it, commenters were concerned that an area may have
difficulty demonstrating conformity in the future if all the projects
planned according to that budget are grandfathered.
EPA believes that current grandfathering requirements are
appropriate and should not be changed. EPA has always believed that
there should only be one point in the transportation planning process
at which a project-level conformity determination is necessary. This
maintains stability and efficiency in the transportation planning
process.
Completion of the NEPA process is the step EPA has selected
historically for grandfathering transportation projects for several
reasons. Making a determination under NEPA is clearly an action to
support or approve an activity, and the Clean Air Act does not allow a
federal agency to take such an action without a conformity
determination. In addition, an air quality analysis is already required
by NEPA. To require this analysis again at a later date may create
redundancies in the transportation process and cause state and local
resources to be used less efficiently.
EPA is partially addressing these stakeholder concerns by
maintaining adverse conformity consequences in the case of SIP
disapproval without a protective finding. As described in section XI.
of this preamble, today's final rule does not allow any new projects to
be added to the plan or TIP beginning 120 days after a SIP is
disapproved without a protective finding. In cases of a SIP disapproval
without a protective finding, areas would only be able to advance
projects in the first three years of the currently conforming plan and
TIP. Therefore, although EPA is not changing the grandfathering of
projects after a SIP is submitted, there are real consequences if a
submitted SIP is ultimately found to have emissions budgets that will
not result in reasonable further progress or attainment. In addition,
EPA believes that with the adequacy requirements added to the rule and
the review of submitted public comments, it is less likely that budgets
which EPA finds adequate will ultimately be disapproved.

III. Other Comments on Conformity Tests

A. Implementation of Budget Test: Submitted vs. Approved Budgets

Some commenters stated that EPA should allow submitted SIP budgets
to override those in approved SIPs for years directly addressed by the
approved SIP. These commenters believed that newly submitted SIPs often
provide a more realistic picture of the future than approved SIPs. Some
believed that, unlike approved SIPs, newly submitted SIPs are more
accurate because they are based on an area's latest planning
assumptions.
Although EPA acknowledges that using updated budgets may be
preferable, EPA does not believe that it is legal to allow a submitted
SIP to supersede an approved SIP for years addressed by the approved
SIP. As stated in the proposal, Clean Air Act section 176(c)
specifically requires conformity to be demonstrated to approved SIPs.
SIP revisions that EPA has approved under Clean Air Act section 110 are
enforceable and cannot be relieved by a submission, even if that
submission utilizes better data. Approved SIP budgets have also been
subject to full technical review and public comment and should not be
replaced by budgets that have not yet been fully analyzed and reviewed.
Some commenters suggested that EPA should institute another adequacy
review process (similar to that being finalized today for submitted
SIPs) which could ensure that submitted SIPs are consistent with
attainment or maintenance. However, this type of process does not
resolve the legal prohibition on overriding approved SIPs, and it would
not be possible to determine whether submitted SIPs are consistent with
attainment or maintenance without EPA's full public review and approval
process. Although submitted SIPs cannot override approved SIPs for
years addressed by the approved SIP, EPA did clarify in the proposal
and this final rule that submitted SIPs can be used for years later
than those addressed by an approved SIP.
Others suggested that, if EPA could not allow submitted SIPs to
override approved SIPs, then EPA should require conformity
determinations to be done using the same models and inputs that were
used in the approved SIP. However, Clean Air Act section
176(c)(1)(B)(iii) requires that conformity determinations ``be based on
the most recent estimates of emissions, and such estimates shall be
determined from the most recent population, employment, travel, and
congestion estimates.'' As stated in the preamble to the 1993
conformity rule (58 FR 62210), it is expected that over time conformity
determinations will deviate from the SIP's assumptions regarding VMT
growth, demographics, trip generation, etc. Conformity is intended to
ensure that a SIP's emission targets are achieved given the most recent
planning assumptions. If conformity cannot be demonstrated using the
most recent

[[Page 43784]]

planning assumptions, either the SIP or the transportation plan and TIP
must be adjusted.
Even though an approved SIP can be changed if another SIP is
submitted and approved by EPA, some commenters believed that EPA's
review and approval of submitted SIPs would not occur in a timely
manner. The commenters urged EPA to conduct expedited review and
approval of submitted SIPs (e.g., 6- to 12-month timeframe), especially
those that are revisions of the currently approved SIP.
EPA recognizes these stakeholder concerns and has already made
expedited approval processes, such as parallel processing, available to
states. In parallel processing, states can develop a draft SIP revision
with close EPA involvement. If all approvability issues are resolved
prior to submitting the SIP to EPA, the state and EPA then request
public comment on the SIP at the same time. If no adverse comment is
received, EPA then finalizes approval as soon as possible after formal
state adoption and submittal, as long as no substantive changes have
occurred and the package is still approvable. Parallel processing is
encouraged when SIP revisions are straightforward, especially when
assumptions are updated and new, significant control measures are
unnecessary. In addition to parallel processing, EPA can use direct
final rulemaking to approve SIPs more quickly in cases where EPA does
not expect adverse comment.

B. VMT Comparison as Substitute for Budget Test

A few commenters recommended that areas be given the option to use
a VMT comparison test instead of the budget test, especially if data
sets and modeling used in the SIP are different than those used in the
plan and TIP. These commenters argued that the present budget test's
analytical inconsistencies could be eliminated if areas were allowed to
replace the budget test with a comparison of the projected vehicle
travel activity in the plan/TIP and that assumed in the SIP. If the
projected VMT in the plan/TIP is consistent with that in the SIP, the
commenters argued that Clean Air Act conformity requirements would be
met.
In order to meet the ``VMT test,'' commenters said that areas would
have to demonstrate that: a) vehicle trips, VMT, and number of vehicles
projected in the proposed plan/TIP have not exceeded these projections
in the SIP; and, b) the transportation system in the proposed plan and
TIP, and vehicle speed distributions on that system, are found through
the consultation process to be in reasonable agreement with the system
and speed distributions assumed in the SIP. Commenters argued that this
idea is supported by Clean Air Act section 176(c)(2)(A) which says that
``emissions expected from the implementation of plans and programs are
consistent with estimates of emissions from motor vehicles and
necessary emissions reductions contained in the applicable
implementation plan * * *'' If an MPO's ``most recent population,
employment, travel and congestion estimates'' (section 176(c)(1)) do
not exceed estimates of these parameters in the SIP, the commenters
believe that the transportation community has fulfilled its Clean Air
Act requirements.
EPA believes that this is not the correct legal interpretation of
Clean Air Act section 176(c)(2)(A), and consequently, a VMT-based test
is not a viable substitute for the budget test. As cited by the
commenters, section 176(c)(2)(A) emphasizes that the projected
emissions from the plan and TIP must be consistent with emissions
targets in the SIP. Emissions estimates depend on numerous factors
other than VMT, such as travel speed, fuels, inspection and maintenance
(I/M), or other technological factors, and thus emissions could
decrease even where VMT increases or vice-versa. Therefore, a VMT-based
test could possibly make it more difficult for some areas to
demonstrate conformity. For example, an area with high VMT growth could
have difficulty passing a VMT-based test, even though it might have a
cleaner fleet of vehicles resulting from electric vehicles or a
successful I/M program. For all of these reasons, EPA is not offering a
VMT-based test in this final rule.

IV. Conformity Tests for Areas That Are Not Required to Submit SIPs

A. Description of Final Rule

Today's action finalizes many of the options that were proposed for
demonstrating conformity in areas that are not required to submit
control strategy SIPs. The July 9, 1996 proposal outlined three options
for determining conformity in these types of areas: (1) create a budget
through the SIP process and use the budget test; (2) create a default
budget based on clean data in areas that have achieved the standard but
have not submitted a maintenance plan; or (3) use either the build/no-
build or ``no-greater-than-1990'' emission reduction test. Today's
final rule keeps the first and third proposed options, while limiting
the second option.
Areas that are not required to submit control strategy SIPs
include: marginal and below ozone nonattainment areas, not classified
carbon monoxide (CO) nonattainment areas, and moderate CO nonattainment
areas with a design value of 12.7 ppm or less. In addition, some
moderate and above ozone nonattainment areas that are meeting the NAAQS
are not required to submit control strategy SIPs. (See May 10, 1995,
memorandum from John S. Seitz, Director of the Office of Air Quality
Planning and Standards, to Regional Air Division Directors, entitled
``Reasonable Further Progress, Attainment Demonstrations, and Related
Requirements for Ozone Nonattainment Areas Meeting the Ozone National
Ambient Air Quality Standard'' for more information about this small
number of ozone areas.)
Under the November 1993 transportation conformity rule, all areas
that are not required to submit control strategy SIPs had two options
for demonstrating conformity. They could choose between satisfying both
emission reduction tests (i.e., the build/no-build and less-than-1990
tests) or submitting a SIP and using the budget test. Areas that
decided to choose the latter option, under the former conformity rule,
were required to perform the build/no-build and less-than-1990 tests
until the submitted SIP was approved.
According to this final rule, all areas that are not required to
submit control strategy SIPs can demonstrate conformity by using either
the build/no-build test or no-greater-than-1990 test (i.e., emissions
must be equal to or less than 1990 emissions); or, by submitting a SIP
through the regular SIP process and using the budget test 45 days after
submittal, provided EPA has not found the submitted SIP inadequate. The
SIP budget could be based on a modeled attainment demonstration or, for
areas with clean data (defined in the conformity rule as complete,
quality-assured monitoring data demonstrating attainment in accordance
with 40 CFR part 58), the SIP budget could be based on the motor
vehicle emissions in the most recent year of clean data.
In addition to these options, moderate and above ozone
nonattainment areas which EPA declares through rulemaking to be ``clean
data areas'' under the May 10, 1995 policy could request that a budget
based on the level of motor vehicle emissions in the most recent year
of clean data be established through that EPA rulemaking process. See
the May 10, 1995 memorandum cited above for more information about
these types of areas.

[[Page 43785]]

B. Discussion of Comments and Rationale

1. Default Budgets for Clean Data Areas
Most commenters supported the proposed options for demonstrating
conformity in areas that are not required to submit control strategy
SIPs. However, some questioned the enforceability of a ``default''
budget for clean data areas because such a budget would be created
through interagency consultation instead of the SIP process. Another
commenter argued that state air quality agencies should not be allowed
to create default budgets without EPA approval and public comment. The
commenter believed that this would be the equivalent of adopting an
element of the SIP, and it should be subject to the conformity rule's
public participation requirements and approval by EPA.
After further consideration, EPA agrees that budgets must be
established through rulemaking; an area cannot adopt a default budget
without EPA review and public comment. As a result, if clean data areas
choose to create a budget, the SIP process must be used (through which
they could establish a budget based on clean data); or, if they are
subject to the May 10, 1995 memo, they could establish a budget through
the EPA rulemaking process described in the memo. Of course, clean data
areas could also choose to use the emission reduction test flexibility
already described above. Because both the SIP and rulemaking processes
provide for EPA review and an opportunity for public comment, EPA
believes that the commenters' concerns are addressed in the clean data
option of this final rule.
EPA does not believe that areas choosing the rulemaking option will
have any additional administrative burden in submitting clean data
budgets for EPA review. Furthermore, since public comment is already a
part of the rulemaking process, additional time will not be needed for
gathering public input.
EPA recognizes there are clean data areas for which EPA has already
completed rulemaking under the May 10, 1995, memorandum. If these areas
are not subject to a control strategy SIP, they have the choice of
using either the build/no-build or no-greater-than-1990 test, or the
budget test if they decide to create one through the SIP process.
Again, if such areas choose to submit a SIP budget, they have the
option of basing the budget on a demonstration of clean data (rather
than modeling) and the budget could be the motor vehicle emissions in
the most recent year of clean data.
One commenter was concerned that, under the proposal, clean data
areas would not have an incentive to submit maintenance plans for
redesignation. EPA acknowledges the commenter's concern and believes
that limiting the default budget option in today's final rule addresses
this concern. However, EPA does believe that other significant
incentives already exist for areas with clean data to submit
maintenance plans.
Another commenter argued that the July 9, 1996, proposal was flawed
because it would allow areas to adopt de facto budgets based on clean
years even if subsequent years have NAAQS violations (thus
demonstrating that budgets derived from clean data years are not
adequate to maintain the standard). EPA believes that the final rule
addresses this concern since any SIP budget would be established only
through the rulemaking or SIP process. If an approved emissions budget
is based on clean data and violations occur, EPA can issue a SIP call
or, if a SIP has not yet been approved, EPA can declare the submitted
budget inadequate during adequacy review. EPA also has the ability to
disapprove a submitted SIP based on clean data if violations occur
prior to approval.
2. Maintenance Areas
A few commenters believed that the proposed options for areas that
are not required to submit control strategy SIPs should also be
available to these areas during the maintenance period.
Since maintenance areas have already submitted SIP budgets and EPA
has approved those budgets, maintenance areas must use the motor
vehicle emissions budget(s) in their maintenance plans to demonstrate
conformity unless a subsequent budget demonstrating maintenance is
approved. As discussed in section III. of this preamble, ``Other
Comments on Conformity Tests,'' Clean Air Act section 176(c)
specifically requires conformity findings to be based on approved SIPs.
Maintenance plans that EPA has approved under Clean Air Act section 110
are enforceable and their budgets must be used for conformity.
3. Emission Reduction Test Flexibility in PM-10 and NO2
Nonattainment Areas
One commenter requested that EPA remove the build/no-build test as
an option for demonstrating conformity in PM-10 (particles with an
aerodynamic diameter of less than or equal to a nominal 10 micrometers)
and NO2 (nitrogen dioxide) nonattainment areas that have not
submitted control strategy SIPs or maintenance plans. Section 93.119(c)
of the proposal, like the November 1993 final transportation conformity
rule, offered PM-10 and NO2 nonattainment areas the option
to use either the build/no-build test or no-greater-than-1990 test to
determine conformity, provided they have not submitted a control
strategy SIP or maintenance plan. The commenter believed that the
build/no-build test will not ensure that the frequency and severity of
existing violations will not be increased, as required by Clean Air Act
section 176(c)(1). Furthermore, commenters did not believe that the
same logic that was used in the November 1993 final rule could be used
to provide the build/no-build test option in ozone and CO nonattainment
areas that are not required to submit control strategy SIPs.
Since the flexibility for PM-10 and NO2 nonattainment
areas was finalized in the November 24, 1993 conformity rule, the
deadline for commenting on this provision has passed, and EPA is not
obligated to respond to this comment. Nevertheless, EPA does believe
that it is appropriate to continue to offer the build/no-build test as
an option in PM-10 and NO2 nonattainment areas. By ensuring
that motor vehicle emissions are less than they would be if no new
transportation investments were made, the build/no-build test does
ensure that the frequency and severity of violations are not increased
as a result of new transportation investments. EPA believes that this
same rationale can be used to justify the build/no-build test option in
ozone and CO areas that are not required to submit control strategy
SIPs. In summary, EPA continues to believe that where no SIP has been
submitted, the build/no-build test is sufficient for areas to meet the
requirements of section 176(c)(1).

V. Rural Nonattainment and Maintenance Areas

A. Description of the Final Rule

In today's action, EPA finalizes the flexibility proposed in
Sec. 93.119, with two minor clarifications. Rural nonattainment and
maintenance areas with submitted or approved control strategy SIPs or
maintenance plans will be allowed to choose among several tests for
demonstrating conformity for years after the time period addressed by
the SIP: (1) the budget test; (2) the emissions reduction tests
(``build/no-build test'' and/or one of the 1990 tests, depending on
what is required of the area's classification); or (3) air quality
modeling.

[[Page 43786]]

In the proposal, EPA's third option was ``air quality dispersion
modeling,'' which was more specific than intended. The final rule's
language has been changed to allow an area to use the air quality
modeling technique it used in its SIP attainment or maintenance
demonstration, even if that technique is not dispersion modeling. For
example, some SIP attainment demonstrations (most commonly in PM-10
areas) are developed using rollback/rollforward techniques based on
emission inventories, and/or chemical mass balance modeling, pursuant
to EPA guidance. Where the SIP demonstration correctly used one of
these techniques, the conformity determination can use the same
technique. EPA will reject SIP budgets during the 45-day review period
if such non-dispersion modeling was used inappropriately.
EPA also clarifies in the final rule that areas electing to use the
emissions reduction tests to demonstrate conformity for the outyears
must perform these tests even if the area has received a NOX
waiver.
Generally, NOX waivers are findings by the EPA
Administrator under Clean Air Act sections 182(b) or 182(f) that
additional reductions of NOX would not contribute to
attainment of the ozone standard by the statutory deadline. Areas have
historically applied for NOX waivers to eliminate the
NOX emissions reduction requirement.
When EPA proposed to allow rural ozone areas with attainment
demonstrations or maintenance plans to have the option of relying on
the NOX emissions reduction tests for the years not
addressed by these SIPs, EPA did not intend to allow these areas the
option of performing no NOX test at all. This would be the
result, however, if such areas could avoid meeting the substitute tests
by receiving NOX waivers. In the November 14, 1995,
conformity amendments (60 FR 57183), EPA stated that areas with
NOX budgets have to conform to these budgets even if they
were granted a NOX waiver. EPA emphasized that ``a
NOX waiver's demonstration that additional NOX
reductions would not contribute to attainment does not necessarily mean
that NOX increases would not affect an area's ability to
attain and maintain the standard. The purpose of a NOX
budget is to prevent NOX emissions from reaching levels that
would threaten attainment or maintenance of the ozone standard.''
EPA is allowing rural ozone areas to substitute the emissions
reduction tests for the budget test as a means of demonstrating that
these areas are meeting the requirements of Clean Air Act section
176(c)(1) that plans, TIPs, and projects not cause or contribute to any
new violation, worsen existing violations, or delay attainment of the
NAAQS. Therefore, for the same reasons a NOX waiver cannot
exempt an area from the budget test, a NOX waiver cannot
exempt an area from the NOX emission reduction tests when
these tests are selected as a substitute for existing NOX
budgets. EPA believes that the clarification in the final rule is
consistent with EPA's original intentions and stakeholders'
understanding of the proposal, and therefore believes that a reproposal
is not necessary to incorporate this minor change.
The choice of a test in rural areas will be determined through the
interagency consultation process and will reflect the consensus of the
state and local air and transportation agencies and the project
sponsor.

B. Rationale and Response to Comments

Most commenters supported the proposal for increased flexibility in
rural areas. EPA changed the language for the air quality modeling
option because EPA agrees with the stakeholder who pointed out that
modeling techniques deemed adequate in certain areas for SIP attainment
demonstrations ought to be adequate in those areas for conformity
determinations as well. EPA originally referred to air quality
dispersion modeling because it is the technique generally required for
SIP demonstrations. Because some PM-10 areas appropriately use air
quality modeling that is not dispersion modeling, EPA has broadened its
language to allow use of these other techniques.
One stakeholder commented that the proposal is illegal, because the
Clean Air Act does not provide for an exemption from the budget test
for rural areas. However, as explained in the proposal's preamble, EPA
believes that providing some flexibility for the years not addressed by
the SIP is consistent with the Clean Air Act. The Clean Air Act
requirement for consistency with the SIP's emissions reduction goals
can be construed to apply only for the years that an individual SIP
revision addresses, where there is another appropriate method of
demonstrating conformity as defined in Clean Air Act section 176(c)(1).
In general, EPA believes that a SIP budget, even if it is not yet
approved by EPA, is a better measure of conformity than the build/no-
build test. For this reason, EPA requires most areas to continue
demonstrating conformity to the SIP emissions budgets even after the
timeframe of the SIP (see section VI., ``Mismatch in SIP/Transportation
Plan Timeframe,'' for more explanation). However, EPA believes it does
have the flexibility to allow conformity to be demonstrated using some
test other than the SIP budget for years not addressed by the SIP, if
that test is more appropriate.
EPA believes that the reasons why the build/no-build test is less
desirable than the budget test for most areas do not apply in the
special circumstances of rural areas. The main critique of the build/
no-build test is that the difference in emissions that it predicts is
often small enough to be within the range of error of the models
themselves. EPA believes this will not be as problematic in rural
areas. Since there are fewer transportation projects and the
transportation network is less complex in rural areas, the build/no-
build test is more reliable. The test is better able to capture the
effects of new projects in such areas. Therefore, EPA believes it is
reasonable to allow the use of the build/no-build test as an option to
demonstrate conformity for the time period of the transportation plan
not covered by the SIP in rural areas.
Several commenters provided ideas for additional flexibilities in
rural areas. One stakeholder suggested that areas should be able to use
the budget from any year of clean data when employing the budget test.
This suggestion is not being implemented today because SIP budgets must
be established through notice-and-comment rulemaking. As stated in
section IV. of this preamble, EPA believes that areas cannot adopt a
default budget based on clean data without EPA review and public
comment. See this section for more details on the options available for
areas with clean data.
Another commenter suggested that areas be allowed to use
alternatives to regional modeling, such as ``subregional'' modeling or
``mesoscale analysis.'' EPA is not including that suggestion in this
section because specific modeling requirements do not apply to rural
areas; they only apply to urbanized areas with populations greater than
200,000. As a result, rural areas already have flexibility in modeling,
provided that their methods consider all regionally significant
projects in the nonattainment or maintenance area.
Several stakeholders suggested that the rule explicitly require
state and local air agency concurrence for the selection of conformity
tests, rather than just consultation. EPA does intend that

[[Page 43787]]

agencies reach agreement on which test to use to demonstrate conformity
in a rural area. However, EPA is retaining the language of the
proposal, because of concerns that requiring concurrence would imply
that the existing conflict resolution process (by which state agencies
can elevate disputes to the governor) cannot be used. EPA believes that
the regulatory language adequately indicates that consensus should be
reached or disputes raised through the conflict resolution process.

VI. Mismatch in SIP/Transportation Plan Timeframe

A. Description of Final Rule

This final rule retains the November 1993 conformity rule's
requirements (described in the proposal as option 1). Conformity must
continue to be demonstrated over a 20-year timeframe, and SIP budgets
continue to apply for conformity purposes for all future years until
superseded by other SIP revisions (except as provided in rural areas,
as described above).
Although EPA is not changing the November 1993 conformity rule
requirements with respect to the mismatch issue, EPA's existing SIP
policy already does provide for some of the flexibility proposed in
option 3, which would have allowed a default emissions budget to be
established for years outside the maintenance plan's timeframe. Because
EPA is aware of the challenges posed by the differing timeframes of the
SIP and the transportation plan, EPA does allow SIPs to establish motor
vehicle emissions budgets for conformity purposes for years outside the
timeframe that the SIP normally addresses. For example, some areas are
developing maintenance plans that include motor vehicle emissions
budgets for conformity purposes for the years 2010 and 2015, even
though the initial demonstration of maintenance is only required to
address ten years. EPA's approval of these budgets is not an approval
of a full 20-year maintenance demonstration; these budgets are for
conformity purposes only and will be superseded when the second ten-
year maintenance plan is submitted.
EPA will require areas to demonstrate that motor vehicle emissions
budgets for years outside the timeframe of the maintenance plan are
consistent with maintenance of air quality standards. EPA will not
permit areas to simply use the motor vehicle emissions in the year of
redesignation as a budget without considering growth in non-mobile
source emissions, which was a possibility discussed in the proposal
under option 3. However, EPA believes it has the flexibility to approve
budgets for years outside the usual maintenance plan timeframe for
conformity purposes based on less rigorous demonstrations than are
required for the Clean Air Act-mandated ten-year maintenance plan.
Whereas normally control measures must be fully adopted in order for
EPA to approve the SIP, EPA would be willing to approve conformity
budgets that were based in part on enforceable commitments to adopt
specific control measures in the future. Because these commitments
would be included in the approved SIP, they would be enforceable by all
parties, including the public. In addition, EPA would consider allowing
the motor vehicle emissions budgets in the last year of the ten-year
maintenance plan to be increased for future years provided offsetting
emissions reductions are adopted or committed to in the SIP.
The ability to establish motor vehicle emissions budgets for
conformity purposes for years outside the normal timeframe of the SIP
is not specifically discussed in this final rule's regulatory text
because it is currently possible under EPA's existing SIP policy, and
therefore no regulatory changes are needed.

B. Rationale and Discussion of Comments

EPA is finalizing option 1 (i.e., not changing conformity rule
requirements to address the mismatch in plan/SIP timeframes) for two
reasons. First, EPA believes there are important benefits associated
with this option, as commenters pointed out (discussed below). Second,
EPA believes there are adequate flexibilities under the existing
conformity rule and EPA SIP policy that will help areas address the
challenges of the timeframe mismatch in a manner that is more
supportive of air quality goals and prudent planning than any of the
other options proposed. The other options proposed included option 2,
which would have required emission reduction tests (``build/no-build
test'' and less-than-1990 test) for demonstrating conformity in years
not addressed by SIPs; and option 3, which would have allowed a default
motor vehicle emissions budget (such as the motor vehicle emissions in
the year of redesignation) to be used for the years outside the
maintenance plan's timeframe.
Many commenters supported option 1 because they believe that
maintaining the SIP's emission targets for the timeframe of the
transportation plan is a central purpose of conformity and perhaps its
most important requirement. Commenters stated that because the
obligation to meet air quality standards persists indefinitely, the
obligation to meet the motor vehicle emissions budget should not
terminate after the attainment date or the last year of the maintenance
plan. According to some commenters, it is appropriate to analyze the
effects of transportation investments over a 20-year timeframe, because
it may in fact take decades for these effects to be fully realized.
They stated that it is better to use a long timeframe and make the
right choices at the outset than to pursue a path for several years and
then try to quickly overcome the adverse consequences of that path. One
commenter pointed out that demonstrating conformity to the SIP's budget
over the 20 years of the transportation plan is the best way to prepare
for the fact that the benefits of fleet turnover do decline over time.
Some commenters preferred option 1 to the other options proposed
because option 1 requires emissions related to growth to be
specifically addressed and tradeoffs to be examined. According to these
commenters, the other options would not accomplish this, and the
conformity determinations that would result from these other options
would not have as much integrity because they would not be based on a
performance target with real meaning (i.e., a SIP budget that supports
reasonable further progress, attainment, or maintenance).
Many other commenters supported option 3, which would have allowed
a default motor vehicle emissions budget for the years after the last
year of the maintenance plan. These commenters believe this option
would be less burdensome than the other options. They also believe that
SIP budgets may be unrealistic because they are not established with a
20-year horizon in mind, and therefore it is not necessarily
appropriate to require areas to conform to them indefinitely. Option 3
was broadly discussed in the preamble to the proposal and included
possibilities that ranged from allowing motor vehicle emissions to grow
to levels in the year of redesignation without consideration of growth
in non-mobile emissions, to allowing budgets to increase only if it is
demonstrated that the standards will be maintained when growth in
mobile, area, and stationary sources is considered. Several commenters
supported option 3 only if the motor vehicle emissions budgets were
based on a demonstration of maintenance that considered all emissions
sources.
The approach that EPA is finalizing combines the benefits of option
1 with some of the flexibility contemplated by

[[Page 43788]]

option 3. EPA agrees with the commenters' reasons for supporting option
1. EPA is sympathetic to the concerns that prompted commenters to
advocate option 3, but EPA believes that the flexibility allowed under
existing SIP policy to establish reasonable budgets outside the
timeframe of the SIP is an effective means of addressing those concerns
without compromising the benefits of option 1. EPA is committed to
assisting areas with the challenges that arise when addressing long-
term emissions impacts. EPA also encourages a collaborative process
between local, state, and federal agencies in order to facilitate
acceptable solutions to these challenges under existing SIP policy.
A few commenters preferred option 2 (emission reduction tests)
because in their specific areas they could pass the build/no-build test
but not the NOX budget test. However, some commenters
opposed option 2 because the emission reduction tests have significant
limitations and would not ensure that regional mobile source emissions
remain consistent with attainment or maintenance requirements. One
commenter stated that the build/no-build test is an imprecise
analytical approach that bears no direct relationship to the attainment
demonstration.
EPA agrees that these arguments against option 2 are compelling.
Allowing areas to use emission reduction tests instead of SIP budgets
would be inconsistent with EPA's action described in section II. to
eliminate the emission reduction tests where SIP budgets have been
established. Overwhelming support has been expressed for this
elimination of the emission reduction tests in such cases, and this has
convinced EPA that option 2 is not a suitable solution for addressing
the mismatch of transportation plan and SIP timeframes. EPA is pursuing
the approach proposed in option 2 only in the limited case of rural
nonattainment and maintenance areas, for reasons specific to such areas
as explained in section V.

C. Response to Specific Comments

Several commenters stated that EPA should allow areas to use any of
the three proposed options. A commenter suggested that the choice of
options would be decided by each area through its own interagency
consultation process. As explained above, EPA believes that the option
being finalized is the most appropriate. One commenter supported option
1 provided areas have more flexibility to account for future programs
that will affect emissions. Currently, areas cannot assume future
programs unless they are adopted or included in the SIP. EPA believes
that the approach being finalized today will allow the flexibility the
commenter is seeking, because it allows budgets established for
conformity purposes to be based on enforceable commitments in the SIP
rather than requiring fully adopted control measures, as needed for
approval as part of a control strategy SIP.
One commenter suggested that the plan should be qualitatively
analyzed for the years beyond the timeframe of the SIP. EPA believes
this would not be consistent with the Clean Air Act's requirement for
the use of emissions estimates for determining conformity. In addition,
EPA believes that both the air quality and transportation planning
processes benefit from long-term quantitative analyses of
transportation plans. EPA believes that areas have sufficient
flexibility in analysis methods to develop a quantitative approach that
is both reasonable and useful.
Some commenters suggested that conformity should not be required at
all in years beyond the timeframe of the SIP. Other commenters
suggested that conformity should not be required until there are tools
adequate to the task. EPA believes this is not consistent with the
Clean Air Act's requirement to demonstrate that the transportation plan
will not cause or worsen violations of air quality standards.
Conformity of a transportation plan cannot be determined unless all
years of the transportation plan are considered. EPA believes that
adequate analytical tools are currently available and are continually
being improved. All areas have great freedom to improve their own
analysis techniques, which EPA supports.
One commenter suggested that the options proposed for rural
nonattainment and maintenance areas be provided for all areas as a way
of addressing the mismatch in transportation plan and SIP timeframes.
The options being provided to rural areas include a choice among the
SIP emissions budget, the emission reduction tests, or air quality
modeling. The emission reduction tests are not being pursued for all
areas as described in the discussion of option 2, above. The reasons
for using the emission reduction tests in rural areas, as described in
section V., are only applicable in rural areas and would not provide a
basis to use these tests in other areas. However, option 1 does give
areas the opportunity to use either the SIP emissions budget or
establish new budgets that are supported by air quality modeling.
Some commenters stated that demonstrating consistency with the
motor vehicle emissions budget established for the attainment year or
the last year of the maintenance plan is not sufficient to demonstrate
that an activity will not cause or worsen air quality violations. These
commenters argue that it must be demonstrated that the motor vehicle
emissions budget is consistent with attainment or maintenance when the
most recent projections about non-mobile source emissions growth are
also considered. EPA does not believe that this is required by the
Clean Air Act. EPA believes that if motor vehicle emissions are less
than or equal to the most recent motor vehicle emissions budgets in the
SIP that was approved as meeting attainment or maintenance
requirements, then it can be stated that motor vehicles are not
``causing or contributing'' to violations, as required by the Clean Air
Act. It is not the role of the conformity requirements to provide
attainment or maintenance plans, but merely to prevent adverse impacts
on such demonstrations.
However, EPA does recognize that consistency with the motor vehicle
emissions budgets for the transportation plan's 20-year timeframe does
not guarantee attainment or maintenance because of the possibility for
growth in non-mobile sources. This is one reason why EPA is not
finalizing a version of option 3 that would allow motor vehicle
emissions to increase above approved SIP budgets without considering
emissions from other sources.

VII. Non-Federal Projects

A. Description of Final Rule

As was proposed, the final rule allows certain regionally
significant non-federal transportation projects to be adopted or
approved during a transportation plan/TIP conformity lapse, provided
the project was included in the regional emissions analysis supporting
the most recent transportation plan and TIP conformity determination.
Non-federal projects are projects which are funded or approved by a
recipient of federal funds designated under title 23 U.S.C. or the
Federal Transit Laws (49 U.S.C. Chapter 53) but which do not rely at
all on any FHWA/FTA funding or approvals.
The final rule clarifies that only those non-federal projects from
the first three years of the most recent conforming plan and TIP (or
supporting regional emissions analysis) may proceed during a conformity
lapse. In the proposal, EPA had simply stated that non-federal projects
in the most recent conforming

[[Page 43789]]

plan and TIP's regional emissions analysis could proceed when a lapse
occurs.

B. Rationale for Clarification and Response to Comments

Most commenters supported the proposal, and many said that it was
appropriate because the emissions impacts from affected non-federal
projects have already been considered and sufficient project reviews
have already occurred. However, some commenters expressed concern that
in their understanding the proposal would facilitate the exchanging of
funds between federal and non-federal projects during a conformity
lapse. Some even implied that there may be areas that would build large
numbers of non-federal projects by exchanging funds, and thereby, avoid
conformity consequences for an indefinite amount of time. There was
concern that because some TIPs cover more than three years, sometimes
even five or more years, a substantial number of non-federal projects
could be built during a conformity lapse. Some of these commenters even
believed that the proposal would allow areas to advance all non-federal
projects in the 20-year transportation planning horizon during a
conformity lapse, thus reducing or removing the incentive to develop
transportation plans and TIPs that actually do conform. EPA did not
intend this in the proposal, and as a result, EPA believes that a
regulatory clarification is necessary in this final rule.
Although commenters suggested possible safeguards to protect
against such abuses, including limiting the number of non-federal
projects that could go forward during a lapse or restricting the
ability to exchange funds between federal and non-federal projects, EPA
believes that the final rule's clarification addresses these concerns.
EPA did not intend that a non-federal project identified for any
year in the 20-year transportation planning horizon could proceed at
any time. This interpretation would be inconsistent with other
regulatory requirements and with the stated rationale for the proposed
non-federal project flexibility. Under DOT's metropolitan planning
requirements (23 CFR 450.332(c)), projects identified for funding in
the first three years of the plan and TIP are the only projects that
can proceed under any approved TIP. New TIPs are required every two
years, and projects from the outyears of an approved TIP cannot be
moved forward without a TIP amendment. Therefore, EPA believes that
allowing non-federal projects in the outyears of the TIP and plan to
advance at any time for conformity purposes is inconsistent with this
general regulatory context. In the proposal, EPA had intended that only
those projects already scheduled to begin in the timeframe of the first
three years of the TIP could proceed during a conformity lapse.
There are several reasons why the final rule's clarification is
consistent with EPA's original intentions and rationale for providing
areas flexibility for non-federal projects. During the development of
the proposal, stakeholders who suggested the proposed non-federal
project flexibility argued that it was appropriate because future plans
and TIPs would have to consider the emissions from non-federal projects
and offset them as necessary. These projects would ultimately have to
be considered in the next TIP in the metropolitan planning process. In
addition, as EPA pointed out in the preamble to the proposal and as
many commenters argued, requiring non-federal projects to have been
included in the most recent conforming plan and TIP ensures that the
emissions consequences of the projects have been considered.
Neither of these rationales would be consistent with allowing a
non-federal project from the outyears to proceed at any time. The
emissions analysis for the plan and TIP would no longer be valid if the
implementation dates of non-federal projects were altered. Allowing
non-federal projects from the outyears to be accelerated during a
conformity lapse so that a new conforming plan and TIP could be
substantially delayed would in effect be allowing the non-federal
projects to escape the scrutiny of the metropolitan planning process
which EPA had relied on in making the proposal. The final rule's
clarification ensures that the flexibility operates as originally
intended by EPA and conformity stakeholders. EPA believes this is fully
consistent with the original proposal and therefore does not require
any reproposal prior to proceeding with final action.

C. Governor Approval

EPA requested comment on whether the governor should be required to
approve each non-federal project that would proceed during a conformity
lapse. EPA did not believe that it could propose such a change because
governor approval is not explicitly required by the Clean Air Act, and
it was unclear whether state and local officials should have the
authority to adopt or approve non-federal projects during a lapse. Due
to the comments received, EPA has decided not to require governor
approval in the final rule.
EPA received many comments on this issue that strongly supported
the proposal to not require governor approval of non-federal projects
affected by the final rule. Many reasons were cited by commenters. Some
said that governor approval isn't necessary since the governor appoints
the directors of the state transportation and air agencies, and in some
cases, governors have even appointed the MPO as his/her designee for
air quality planning. Others emphasized that the conformity rule
already provides for involving the governor, when necessary, through
the conflict resolution process. Many argued that local non-federal
projects are usually time-sensitive and many local governments fund
these projects in order to expeditiously move them through the planning
process. In this case, requiring governor approval is unnecessary and
would impede rather than facilitate the process of non-federal project
implementation. Finally, some believed that it was not appropriate for
governors to have authority over approving local non-federal projects.
EPA agrees generally with commenters and believes that requiring
governor approval is not necessary. Therefore, EPA is not requiring
governor approval of non-federal projects during a conformity lapse.

D. Responses to Other Comments on Non-Federal Projects

EPA received other comments on the proposed non-federal project
flexibility which did not result in changes to the proposal.
1. Comments Opposing Statutory Interpretation
One commenter argued that any exemption for non-federal projects
would violate the statutory requirement that any such project only be
approved or funded if it either ``comes from a conforming plan and
program,'' or its emissions when considered with those of ``the
conforming transportation plans and programs within the nonattainment
area'' do not exceed the applicable emissions budgets. The commenter
argued that the present tense of the operative verbs in the statutory
language does not allow exemptions for projects that come from a plan
and program that no longer conform. The commenter also argued that this
exemption cannot be justified as a grandfathering mechanism because it
allegedly applies to projects that have not yet satisfied applicable
federal requirements. Finally, the commenter objected that the proposal
allows state DOTs to continue to build

[[Page 43790]]

projects with state funds during periods when the metropolitan
transportation plans fail to satisfy the Clean Air Act's requirements
for emission reductions, and therefore leads to a delay in attainment.
EPA believes that it is appropriate to allow non-federally funded
projects that have previously satisfied conformity requirements to
proceed during a conformity lapse because the existence of a conforming
plan and TIP is not necessary to facilitate the implementation of such
projects. As to the commenter's concern about potential emissions
increases, any future plan and TIP will have to account for and offset
if necessary the emissions of any non-federal projects that are
implemented during a conformity lapse.
EPA acknowledges that there is some tension with the present tense
statutory language concerning the existence of a conforming plan and
TIP. However, EPA believes that this is a proper case of grandfathering
projects that had been previously found to satisfy the applicable
federal conformity requirements. The only obligation imposed by the
conformity rule on non-federal projects is to account for project
emissions in a conforming plan and TIP. If this has been done, EPA
believes that it is appropriate to allow projects in the timeframe of
the first three years of the plan and TIP to proceed towards
implementation, so as not to interfere with the priorities of non-
federal entities funding such projects.
2. Changes in Implementation Date
Another commenter said that it was unclear whether a non-federal
project could go forward during a lapse if the project's design concept
and scope had changed; or, if the project's implementation date had
changed in a manner that changed emissions in a milestone or analysis
year. Under the proposal and this final rule, a non-federal project
cannot go forward during a conformity lapse if its design concept and
scope has changed significantly. A non-federal project also cannot go
forward if its implementation date changes in a manner that changes the
emissions that the emissions analysis supporting the most recent
conforming plan and TIP projected for a given analysis year. In either
case, a new air quality analysis would be needed to ensure that the
project would still conform, and it would be inappropriate to allow
such projects to proceed based on the analysis in the most recent plan/
TIP. The final rule's clarification should reduce confusion on this
point.
3. Comments on Original Conformity Rule
One commenter objected to the provisions of the original conformity
rule that do not require conformity determinations for non-federally
funded projects. The commenter included detailed statutory arguments
alleging that Clean Air Act section 176(c) on its face requires
conformity determinations for all transportation projects, and the
commenter also included citations to the legislative history supporting
these allegations. The commenter also argued that non-federal project
sponsors should provide a public process prior to determining that
emissions from non-federal projects are consistent with applicable
emissions budgets.
EPA's proposal did not cover this aspect of the conformity rule,
which has been final since 1993. EPA did not intend to reopen the issue
of whether non-federal projects should undergo conformity
determinations when it proposed to allow certain non-federal projects
to proceed during a lapse. As EPA explained in the preamble to the 1993
conformity rule, Clean Air Act section 176(c)(2)(C) clearly
distinguishes non-federal projects from those projects required to
conduct a conformity determination, requiring only that non-federal
projects be considered in a regional emissions analysis prior to
adoption or approval. Non-federal projects are not covered in the
requirement to conduct a conformity determination in section 176(c)(1),
which applies only to actions of federal agencies and metropolitan
planning agencies. For these reasons, EPA is not responding in full to
comments submitted on this issue. For more explanation of EPA's
rationale for the provisions of the original conformity rule, see the
preamble to the final rule at 58 FR 62188, 62204 (Nov. 24, 1993).
Finally, since federal agencies do not approve non-federal projects,
such approvals are not subject to the requirements of the federal
Administrative Procedure Act. Non-federal project sponsors would have
to comply with any applicable public participation processes required
under state law.

VIII. Deadline for Use of Network Models and Affected Areas

A. Description of Final Rule

Today's action finalizes the proposal to require serious CO and
serious, severe, and extreme ozone areas to use network models for
conformity determinations by January 1, 1997. In addition, as proposed,
these network modeling requirements are revised so that they only apply
to metropolitan planning areas with an urbanized area population over
200,000. EPA continues to believe that network modeling requirements
are most important for large urbanized areas, and therefore believes
that it is appropriate for the conformity rule to focus its specific
modeling requirements on them. See section IX.A. for a description of
the final rule's requirements for network models.
As stated in the proposal and required under the original
conformity rule, whether or not an area is required to use a network
model, all areas must use the consultation process to select regional
models and assumptions, as required by Sec. 93.105(c).

B. Rationale and Discussion of Comments

Most commenters supported the final rule's limiting of network
modeling requirements to serious and above areas with an urbanized
population over 200,000. Commenters agreed with EPA that network
modeling is not always appropriate in rural or urban areas with smaller
populations, and therefore, should not be required in these areas.
One commenter suggested that all urban areas with a population
greater than 50,000 people should also be required to use network
models because these models are simple and inexpensive. However, the
commenter did not believe that the proposal would seriously weaken the
conformity process, since most of these smaller cities already use
network models for conformity analyses.
As previously stated, EPA believes that network modeling
requirements are most important for large urbanized areas. As a result,
EPA is not changing the proposed population threshold. However, EPA
also notes that Sec. 93.122(c) of the conformity rule requires areas
that are already using network models to continue using them, even if
they are not serious or above areas or have a population less than
200,000. EPA and DOT will consider the specific technical needs of
smaller areas when developing future modeling guidance.
A couple of commenters supported stratifying the network modeling
requirements by size of urban area. EPA believes that the final rule in
part addresses this concern by only requiring larger urbanized areas to
adhere to the network modeling requirements. However, EPA does not want
to create a complicated stratification system that would require
multiple sets of modeling requirements. Therefore, EPA did not

[[Page 43791]]

change the rule in response to this comment.
As proposed, today's action also extends the deadline for
implementing the network modeling requirements from January 1, 1995, to
January 1, 1997. A few commenters suggested that MPOs that are not
meeting the rule's network modeling requirements should be put on a
timetable for compliance. Other commenters thought that extending the
deadline was unnecessary due to the ease of implementing such a network
model, especially since the majority of areas already have a network
model in place. They also felt that an extension would seriously weaken
the modeling regulation. Some commenters stated that the extension of
the deadline is obsolete, since the final rule would be published after
January 1, 1997.
EPA acknowledges that the January 1, 1997, deadline has already
passed. The original conformity rule required that areas use network
models in conformity analyses by January 1, 1995, and when the proposal
was being developed, most areas had achieved the rule's network
modeling requirements by this deadline. However, as discussed in the
proposal, a few areas had not yet complied with the deadline, and EPA
believed that an extension until January 1, 1997, would be adequate to
address their difficulties.
EPA did consider extending the deadline even further when it became
apparent that the final rule would not be effective before January 1,
1997. However, reproposal would have been necessary to significantly
extend the proposed January 1, 1997, deadline, and EPA believes it is
likely that the few areas in question will have adequate network models
developed before a reproposal could be finalized.
For all of these reasons, EPA is retaining the January 1, 1997,
deadline. EPA agrees with the commenters that the majority of affected
areas are already using network models. EPA and DOT are currently
working with the two areas that have not yet met the network modeling
requirements so that they will overcome their unique circumstances and
meet the requirements in the future.

IX. Content of Network Modeling Requirements in Serious and Above Ozone
and CO Areas

A. Description of Final Rule

In today's final rule, EPA is streamlining the conformity rule's
modeling requirements and committing to collaborate with DOT to develop
future modeling guidance. Specifically, EPA is eliminating several
modeling criteria from regulatory text while retaining those criteria
that establish minimum acceptable practice.
The proposal requested comment on three options for addressing the
modeling criteria in the conformity rule. Option 1 proposed to
eliminate all of the 11 required attributes of network models in the
original November 24, 1993, final transportation conformity rule and
address the attributes only in guidance. Option 2 would have retained
all of the original modeling attributes. Option 3 proposed to
streamline the original requirements for network models and address the
eliminated attributes in guidance. Today's action finalizes option 3
with some minor modifications.
The final rule includes six required elements for network modeling
in serious and above ozone and CO areas with an urbanized population
over 200,000. These elements include the five that were proposed as
option 3 (with minor wording changes), as well as the November 1993
conformity rule's requirement in Sec. 51.452(b)(1)(iv)/
Sec. 93.130(b)(1)(iv) for reasonable agreement between zone-to-zone
travel times used in trip distribution and the travel times resulting
from traffic assignment.
Specifically, this final rule requires network-based models to be
validated against observed counts (peak and off-peak, if possible) for
a base year that is not more than ten years prior to the date of the
conformity determination. Model forecasts must be analyzed for
reasonableness and compared to historical trends and other factors, and
the results must be documented. Land use, population, employment, and
other network-based model assumptions must be documented and based on
the best available information. Scenarios of land development and use
must be consistent with the future transportation system alternatives
for which emissions are being estimated. The distribution of employment
and residences for different transportation options must be reasonable.
A capacity-restrained traffic assignment methodology must be used,
and emissions estimates must be based on a methodology which
differentiates between peak and off-peak volumes and speeds, and which
uses speeds based on final assigned volumes. Zone-to-zone travel
impedances used to distribute trips between origin and destination
pairs must be in reasonable agreement with the travel times that are
estimated from final assigned traffic volumes. Where use of transit
currently is anticipated to be a significant factor in satisfying
transportation demand, these times should also be used for modeling
mode splits. Finally, network-based models must be reasonably sensitive
to changes in the time(s), cost(s), and other factors affecting travel
choices.
EPA believes that the streamlined criteria and clarified rule
language will assist areas in implementing the rule's network modeling
provisions. The final rule does not create any new network modeling
requirements for large, urbanized serious and above ozone and CO areas.
As stated in the proposal, EPA and DOT will develop modeling
guidance in the future to address some of the modeling requirements
that were eliminated from the final rule and to foster the exchange of
information on current and future modeling improvements. As discussed
later in this section, EPA and DOT are committed to an open stakeholder
process about modeling procedures that will begin shortly after the
rule becomes effective.

B. Rationale and Discussion of Comments: Selected Option

There were commenters who supported each of the three proposed
options for the content of the network modeling requirements. Some
supported option 1 because they believed that eliminating all modeling
attributes would simplify the conformity rule and create maximum
flexibility for areas. Other commenters argued strongly for option 2,
which would have retained all 11 modeling attributes from the original
rule. According to one commenter, removing all of the modeling
attributes from the rule would have detrimental effects on the entire
conformity process. Finally, many commenters from the transportation
and environmental communities supported option 3, which proposed to
streamline the modeling requirements without fully eliminating them.
These commenters believed that having some baseline modeling criteria
in the rule ensures national consistency of network models while
streamlining the rule to allow for flexibility at the state and local
levels.
As previously stated, this final rule streamlines the original
conformity rule's network modeling criteria by eliminating some
criteria and clarifying the rule's language. EPA is retaining some
modeling requirements in this final rule because EPA agrees with
commenters that minimum modeling standards are an important component
of the conformity process. Many commenters believed that all or some of
the original modeling criteria should be retained in the final rule,
because without them, modeling practice would

[[Page 43792]]

become highly variable across the country. They also thought that
eliminating all criteria would undermine the integrity, reliability,
and credibility of the process for assessing the expected impacts of
transportation investments on travel demand, travel behavior, and
estimates of future vehicle miles traveled (VMT) and emissions. Others
believed that having modeling criteria in the conformity rule has
spurred the funding and development of state and local transportation
model improvements. Finally, some pointed out that sound network models
are needed for other processes besides conformity, such as SIP
development, and therefore should be retained.
Other commenters were concerned that lawsuits would increase if all
of the modeling attributes were eliminated, due to the inconsistency of
requirements across the country. According to commenters, the outcomes
of these suits would be hard to predict and money would be wasted in
the adversarial process.
EPA agrees with these comments and believes that the final rule
addresses them. EPA also agrees that nationally consistent and
enforceable minimum standards are central to the integrity of the
conformity process. Minimum standards clarify the expectations of all
agencies involved in the conformity process and thus ensure some equity
among all areas.
One commenter argued that EPA cannot eliminate all of the modeling
attributes because they are a regulatory requirement which cannot be
substituted with unspecified guidance that is developed outside of the
rulemaking process. EPA agrees with this comment and is addressing it
by retaining minimum standards in this final rule.
Although some commenters supported option 1, EPA does not believe
that eliminating the modeling requirements is necessary to achieve the
objectives of these particular commenters. Some supported option 1
because eliminating all modeling criteria would allow areas to tailor
their network models to satisfy their current modeling and air quality
planning needs. According to one commenter, this option would
distribute resources and technical expertise appropriately in state and
local agencies. Commenters also believed that under option 1 areas
would be able to do sound quantitative analysis while having the
flexibility to accommodate modeling improvements and demographic
changes in their area. A couple of commenters suggested states should
have the authority to determine network model attributes on an area-by-
area basis, and one approach for this is to allow state-level approval
of an area's model subject to the interagency consultation process.
EPA believes that areas have the flexibility to appropriately
tailor their models and distribute their resources under option 3 as
well as option 1. The conformity rule's modeling requirements define
minimum acceptable practice, and beyond this, areas have flexibility to
determine appropriate modeling practices and accommodate modeling
improvements through interagency consultation. EPA does not believe
that areas should be able to use models that do not meet minimum
standards of acceptable professional practice, for the reasons
described in this section.
One commenter stated that the criteria in options 2 and 3 are
accounted for in some way in existing practice, and that requiring them
does not advance the state of the practice and may hinder it if future
developments lead to improved, but different, methodologies. Another
commenter suggested that by eliminating all modeling criteria, EPA and
DOT could incorporate future modeling improvements by revising the
guidance rather than having to go through the difficult and time-
consuming process of revising the rule. Others believed option 1 would
give agencies across the country access to technical changes and
expertise which may not be available to them on a case-by-case basis,
and may provide a better way of communicating updates and improvements
in network modeling procedures.
EPA does not believe that establishing baseline modeling criteria,
as is being done in this final rule, will inhibit the adoption of
future modeling improvements. EPA agrees that future modeling guidance
should provide information to state and local agencies about modeling
updates, and EPA and DOT are committed to working with stakeholders to
exchange ideas in the guidance development process. However, EPA does
not believe it is necessary to eliminate the rule's modeling
requirements in order to issue future modeling guidance. As general
modeling practices improve, EPA and DOT will make periodic updates in
the form of non-enforceable modeling guidance, rather than future
amendments to the conformity rule.
An area that has not yet implemented the currently required model
improvements supported option 1 because the area believed option 1
would provide flexibility and make a conformity lapse for this area
less likely. EPA believes that it would be inappropriate to eliminate
all of the modeling criteria just because a few areas are having
temporary difficulty achieving them. This stakeholder concern was also
raised in the context of extending the deadline for implementing
network modeling requirements. EPA considered the merits of this
comment, and as outlined above, decided that a reproposal to extend the
deadline could not be completed in time to provide relief to the few
affected areas. As previously mentioned, EPA and DOT are assisting the
two areas without adequate network models to achieve the minimum
standards in this rule.
EPA believes that option 3 also addresses the concerns of the
commenters who supported option 2. These commenters seemed most
concerned with whether any modeling requirements would be retained in
the rule; option 1 would have eliminated all of the rule's network
modeling requirements. Many of the commenters who supported option 2
also supported option 3, provided there were modifications for some of
the language in option 3. EPA believes that the changes made to option
3, which are discussed below, make the final rule's language more
streamlined, clear, and useful than the 1993 conformity rule language
proposed for retention in option 2.
A few commenters who supported option 3 also thought that areas
should not be required to use network modeling improvements in the
conformity process prior to their application in the SIP process. The
commenters believed this would remedy problems associated with
inconsistencies between the models used in conformity analysis and
those used in SIP development. EPA recognizes the commenters' concerns
about the implementation difficulties that may occur as a result of
model improvements. However, Clean Air Act section 176(c)(1)(B)(iii)
requires conformity determinations to ``be based on the most recent
estimates of emissions.'' EPA believes that areas must use the most
current tools available at the time of the conformity determination, in
accordance with the Clean Air Act. Using the best models and
assumptions will also produce the best emissions estimates on which
areas will base decisions regarding transportation and air quality. EPA
also notes that areas already have the ability to use the consultation
process to coordinate the introduction of transportation modeling
improvements into their planning processes. For these reasons, EPA is
not finalizing the commenters' suggestion.

[[Page 43793]]

C. Future Modeling Guidance and Response to Comments

As stated in the proposal, EPA and DOT will develop modeling
guidance in the future. This guidance will address some of the modeling
requirements that were eliminated from the final rule; provide guidance
on implementing modeling requirements; and facilitate the exchange of
information on advancements in modeling. EPA and DOT are committed to
working with stakeholders in the development of the guidance, an idea
which was supported by many commenters. This process will begin soon
after this rule becomes effective, and will include stakeholder
participation in workshops for developing the guidance. In addition,
EPA and DOT will make drafts available for stakeholder comments. This
joint federal, state, and local effort will bring together the
expertise to assure national consistency and meaningful emissions
results in conformity analyses.
Some commenters were concerned that the guidance would be mandatory
and that future guidance updates would be difficult to implement if it
were mandatory. Today, EPA clarifies that the guidance will not be an
enforceable requirement, although EPA and DOT encourage use of future
guidance on a voluntary basis as deemed appropriate by affected state
and local agencies. There is also no specific date by which future
modeling guidance must be used, or by which models are required to be
improved in accordance with future guidance, since the use of future
guidance is not an enforceable requirement. Areas will decide upon how
to implement modeling guidance using the interagency consultation
process.
Another commenter said that each MPO should have the responsibility
to demonstrate the adequacy of their model through documentation, and
such documentation should be included as an appendix to the area's
conformity package. EPA agrees with this comment and encourages MPOs to
submit such documentation with their conformity determinations.

D. Rationale and Discussion of Comments: Specific Criteria

As discussed above, this final rule specifies six requirements for
network models for serious and above ozone and CO areas. These replace
the 11 that were required by the November 1993 conformity rule. This
final rule includes the five requirements that were proposed as option
3, as well as a requirement from the November 1993 conformity rule that
was not originally proposed as part of option 3 (but was included in
proposed option 2, which included all requirements of the 1993 rule).
Several minor changes were made to the wording proposed in option 3 in
order to respond to comments, reduce ambiguity, and streamline the
text.
EPA proposed to require network-based models to be validated
against peak and off-peak ground counts for a base year that is not
more than ten years prior to the date of the conformity determination.
The final rule requires validation against ``observed'' counts rather
than ``ground'' counts because the term ``ground'' counts sometimes
implies automobile counts only. In fact, models should be validated
against counts for all modes, including transit, bicycle, and
pedestrian. EPA believes that because ``observed'' counts is a more
general term, it more appropriately conveys the intent of the proposed
requirement.
EPA has also qualified the proposed requirement for validation
against peak and off-peak counts so that validation against both peak
and off-peak counts is only required where it is possible. The November
1993 conformity rule simply required validation against ground counts;
there was no reference to peak and off-peak. When EPA proposed option
3, it did not intend to impose any new or more stringent network
modeling requirements. Since the time of the proposal EPA has become
aware that not all areas collect peak and off-peak counts. As a result,
although EPA continues to believe that validation against peak and off-
peak counts is preferable, the rule only requires it where it is
already possible given available data.
A commenter suggested that the conformity rule should require areas
to validate their models for a second year at least three years before
or after the base year whenever possible. The commenter also suggested
that the rule require validation against peak and off-peak travel
demand, traffic volume, speed, and mode share data for household and
commercial travel. EPA did not incorporate these suggestions in the
conformity rule because the modeling requirements are only intended to
outline minimum practice, and in addition, EPA intends for these
amendments to streamline the existing rule. The EPA/DOT modeling
guidance will have further discussion about best practices and other
advances in validation techniques, and EPA believes that this will be a
better forum to address the commenter's ideas.
This final rule adds to the proposed validation requirement a
sentence specifying that model forecasts must be analyzed for
reasonableness and compared to historical trends and other factors, and
that the results must be documented. This sentence was added for
several reasons. First, a commenter suggested that the conformity rule
should require model forecasts to be compared to documented historical
trends in travel behavior, such as changes in per capita vehicle trips
and VMT, trip length, mode shares, and time-of-day-travel, and require
significant differences between trends and forecasts to be explained.
EPA agrees that this is minimum acceptable practice and has added
language to the conformity rule accordingly. The language that is
included in the final rule is more general than that suggested by the
commenter, and EPA plans for the EPA/DOT modeling guidance to address
the issue in more detail. EPA also added this language because it
better reflects what EPA intended when it proposed that network-based
modeling inputs (such as land use, population, and employment) be
appropriate to the validation base year. This language is consistent
with the proposal on this issue and does not require reproposal prior
to final action.
The second network modeling requirement in the final rule requires
land use, population, employment, and other network-based model
assumptions to be documented and based on the best available
information. The proposal's requirement for these assumptions to be
``appropriate to the validation base year'' has been eliminated in
favor of the new language described above that requires reasonableness
checks as part of validation. A commenter suggested that the proposed
requirement be expanded to refer not only to land use, population, and
employment assumptions, but also demographic and spatial attribute
assumptions. EPA believes that the final rule's reference to ``other
network-based modeling inputs'' is sufficiently inclusive, and
specificity such as the commenter suggests is more appropriate to the
EPA/DOT modeling guidance.
The final rule's third network modeling requirement states that
scenarios of land development and use must be consistent with the
future transportation system alternatives for which emissions are being
estimated. This is substantially similar to the language proposed as
the fourth modeling requirement in option 3, with minor wording
adjustments for the sake of clarity. The final rule also includes a
sentence stating that the distribution of employment and residences for
different transportation options must be reasonable. This statement is
intended

[[Page 43794]]

as further clarification of what was intended by the original proposed
language. Appropriate consideration must be given to how major
anticipated transportation system improvements might influence
development and, in turn, how that might affect the forecasted
distribution of population and employment used to estimate travel and
emissions.
A commenter suggested that instead of the proposed language, EPA
should require that areas make reasonable adjustments to land use
assumptions between scenarios to account for effects of changes in
accessibility on the likely timing and pattern of development, using
the best methods available. EPA does not believe it is appropriate for
the conformity rule to specifically require the use of the ``best''
methods, because cutting-edge practices may not be reasonably available
at the same time in all areas subject to conformity's network modeling
requirements. With this exception, EPA believes that the commenter's
suggestion is basically a restatement of the language that is being
finalized.
The final rule's fourth network modeling requirement states that a
capacity-sensitive assignment methodology must be used. In addition,
emission estimates must be based on a methodology which differentiates
between peak and off-peak link volumes and speeds and uses speeds based
on final assigned volumes. This additional language clarifies the
proposed requirement that ``peak and off-peak travel demand and travel
times must be provided,'' which did not indicate which step in the
modeling process was being referred to. EPA in fact simply intends that
emissions be calculated on the basis of peak and off-peak speeds
separately and applied to peak and off-peak final assigned volumes,
regardless of whether these assigned volumes are based on peak and off-
peak modeling or are modeled on a 24-hour basis.
The final rule's fifth network modeling requirement is based on
Sec. 51.452(b)(1)(iv)/Sec. 93.130(b)(1)(iv) of the November 1993
conformity rule, which requires feedback of travel times resulting from
traffic assignment to travel times used in trip distribution. Although
this requirement was not proposed as part of option 3, EPA received
comments based on proposed option 2 that this requirement of the
original rule should be retained. Commenters pointed out that this type
of consistency in the evaluation of travel time is almost universally
recognized to be scientifically valid. A commenter stated that not
requiring feedback would allow analyses to be manipulated to produce
desired results. Another commenter stated that most MPOs have already
implemented full feedback, and it is easy to perform and more accurate
than partial feedback. Commenters submitted technical reports and
papers to the docket in order to document their claims that full
feedback is recognized to be a necessary and sound modeling
improvement.
EPA agrees with commenters that there is clear theoretical
justification for feedback between traffic assignment and trip
distribution, and that feedback may be essential to accurate forecasts
when congestion exists. In addition, EPA agrees that full feedback is
already widely available and used. As a result, EPA believes it is
appropriate to retain the feedback requirement.
The regulatory language has been slightly modified from the
November 1993 rule to read that zone-to-zone travel impedances used in
trip distribution must be in reasonable agreement with travel times
that are estimated from final assigned traffic volumes. The language
now refers to ``impedances'' rather than ``travel times'' because trip
distribution impedances may reflect more than just vehicle travel time
(e.g., cost, travel times by other modes, etc.). The language refers to
travel times ``estimated from final assigned traffic volumes'' rather
than travel times ``which result from'' traffic assignment in order to
reflect the fact that speeds should be estimated by post-processing
assigned volumes.
The final rule's sixth and final network modeling requirement is
for network-based models to be reasonably sensitive to changes in the
time(s), cost(s), and other factors affecting travel choices. EPA's
proposed option 3 would have required models to be reasonably sensitive
to trip-making changes due to changes in the cost, travel time,
capacity, and quality of all travel choices, if the necessary
information is available. EPA has eliminated the reference to ``trip-
making changes'' because EPA received comments indicating that this
implies a requirement for trip generation to be dependent on
accessibility. This is not what EPA intended. The November 1993
conformity rule strongly encouraged a dependence of trip generation on
the accessibility of destinations, but it was not specifically
required. EPA continues to believe that such a trip generation
requirement is not widely available, minimum practice. In addition to
deleting ``trip-making changes,'' EPA made other modifications to the
proposed requirement in order to streamline the language. By making the
language more general, EPA believes that the qualification ``if the
necessary information is available'' is no longer necessary. EPA has
therefore eliminated this language.
EPA received comment that Sec. 51.452(b)(1)(v)/Sec. 93.130(b)(1)(v)
of the November 1993 conformity rule should be retained in addition to
the other paragraphs proposed as option 3. Section 51.452(b)(1)(v)/
Sec. 93.130(b)(1)(v) of the November 1993 conformity rule required
free-flow speeds on network links to be based on empirical
observations. EPA is not including this requirement in the final rule
because it has been widely misinterpreted, and because issues relating
to the use of speeds in network models are complex enough that they are
best handled in modeling guidance, where they can be fully discussed.
The November 1993 requirement was read by some to require significant
data collection efforts. In fact, EPA had simply intended that
available empirical information be used instead of posted speed limits.
In addition to creating this misinterpretation, the original language
was not clear about which step of the modeling process it referred to,
and whether it was directed at input assumptions or outputs.
EPA believes that this issue warrants a full discussion in the EPA/
DOT modeling guidance, and that the original regulatory requirement
regarding free-flow speeds should be eliminated from the streamlined
rule in order to avoid confusion. However, EPA and DOT would like to
emphasize that input network speed assumptions used in model
application must be consistent with speed assumptions used in model
development and calibration, and that these assumptions and calibration
techniques should be documented. EPA and DOT recognize that free-flow
impedance inputs into traffic assignment may not reflect empirically
observed free-flow speeds, because these input impedances may reflect
considerations that affect travel behavior other than travel time, such
as driver preferences for using specific classes of facilities. If
free-flow impedance inputs used in traffic assignment deviate
significantly from observed free-flow speeds, the documentation should
include a discussion of the differences and rationale for adjustments
made.
In addition, since emissions estimates are extremely sensitive to
vehicle speed, EPA and DOT recommend that speeds be estimated in a
separate step after traffic assignment (also known as ``post-
processing''), using refined speed-

[[Page 43795]]

volume relationships and final assigned traffic volumes. Post-
processed speeds estimated in the validation year should be compared
with speeds empirically observed during the peak and off-peak periods.
These comparisons may be made for typical facilities, for example, by
facility class/area type category. Based on these comparisons, speed-
volume relationships used for speed post-processing should be adjusted
to obtain reasonable agreement with observed speeds. Regardless of the
specific analytical technique, every effort must be made to ensure that
speed estimates are credible and based on a reproducible and logical
analytical procedure.

X. Adding Non-Exempt Projects to the Plan/TIP Without Regional Analysis

A. Description of Final Rule

In today's final rule, EPA is not finalizing the flexibility
proposed in Sec. 93.122(b)(4), which would have allowed projects to be
added to the plan and TIP based on an alternate emissions analysis that
does not use network modeling (for areas that are required to use
network models, i.e., serious and above areas with an urbanized
population over 200,000). This final rule retains the 1993 conformity
rule requirement that every plan/TIP amendment that involves regionally
significant, non-exempt projects requires the same level of regional
emissions analysis. For the purposes of this discussion, a non-exempt
project is any transportation project other than those listed in
Sec. 93.126, ``Exempt projects,'' and Sec. 93.127, ``Projects exempt
from regional emissions analysis.''
Areas that are not serious or above or do not have an urbanized
population over 200,000 are not affected by the proposal or this change
to the proposal, because they are not subject to requirements for
network models.

B. Rationale

Based on stakeholder comments received, EPA has determined that the
flexibility to add projects without a regional emissions analysis would
have to be accompanied by safeguards or limitations that were not
proposed. EPA believes that the restrictions that would have to be
imposed on the flexibility would outweigh its benefits.
EPA agrees with a commenter who pointed out that regulatory
requirements that govern how satisfaction of a conformity test is
demonstrated cannot be removed and replaced with unspecified guidance
that is not subject to notice and comment. EPA believes that the
commenter is correct in asserting that guidelines for how the alternate
emissions analysis would have to be performed would have to be included
in regulatory language, if the flexibility were to be finalized. Such
additional regulatory language would require reproposal because it is a
significant departure from what was originally proposed; EPA did not
propose any specific guidelines or limitations for this flexibility in
either the preamble or regulatory language of the July 9, 1996,
proposal.
Other commenters expressed serious concerns that the flexibility to
add projects without analysis could undermine the coordinated planning
process and achievement of air quality objectives unless some
safeguards are included. Suggestions for limitations and safeguards
included adding minimum criteria for alternate analysis methodology in
the rule; limiting the flexibility to projects which are unlikely to
cause major long-term changes in travel and development patterns;
limiting the flexibility to a certain number of projects per planning
cycle; or requiring that the emissions from the existing plan and TIP
be below a minimum threshold of the applicable emissions budget.
Commenters were also concerned that safeguards needed to be applied
consistently throughout the country. Including such safeguards would
require reproposal, and could result in additional rule complexity that
would hamper use of the proposed flexibility.
Because EPA believes it is legally compelled to include minimum
guidelines for alternate emissions analysis in the regulatory text,
EPA's choice was to either repropose regulatory guidelines and
safeguards or eliminate the proposed flexibility. EPA is choosing the
latter in today's final rule because the few alternate methodologies
suggested by commenters were not sufficient to provide a basis for EPA
to propose general regulatory guidelines. In addition, EPA believes
that additional regulatory text would outweigh the benefits of the
flexibility.
The few methodologies proposed by stakeholders were not sufficient
to form the basis of nationally applicable, minimum guidelines for
alternate emissions analysis. When EPA proposed the flexibility, it was
seeking a procedure that would yield similar results as a full-scale
regional analysis but with less effort. However, the methodologies
suggested by commenters were sketch planning techniques, which are
ancillary to but not substitutes for network modeling. While sketch
planning techniques may be appropriate for certain projects in certain
circumstances, the commenters did not suggest guidelines that would
delineate when sketch planning techniques may be an adequate
approximation or how these techniques could be replicated nationally.
Based on comments received during the development of the proposal
and during the comment period on the proposal itself, EPA and DOT
believe that regulatory constraints on the proposed flexibility would
defeat the flexibility's purpose. Many commenters did not believe EPA
could or should develop alternate analysis techniques that would apply
nationally, because the value of the flexibility would be its
application on a case-by-case basis. In addition, many stakeholders
want the regulatory text to be streamlined and procedural modeling
guidelines to be minimized.
EPA and DOT also believe that the possible benefits of the proposed
flexibility do not warrant the complication of a new set of modeling
guidelines. Commenters have indicated that the proposed flexibility
would not have a large impact on day-to-day implementation of the
conformity rule. Many commenters stated that the flexibility would be
used infrequently, or only in limited circumstances. Some commenters
believe that a full-scale regional analysis is just as easy as using an
alternate sketch planning method. For example, a commenter indicated
that adding a project and running the regional model again is not time-
consuming once the network for the plan has already been coded. EPA and
DOT believe the time and effort spent in developing an alternate
procedure and getting agreement from all involved agencies seems
greater than that involved in running the regional model.

C. Pilot Program

Although EPA did not grant the general analysis flexibility in
today's final rule, EPA and DOT remain willing to consider alternate
procedures on a case-by-case basis for determining the impact of
transportation projects, since a substitute may prove to be more
expeditious and less costly in certain circumstances than a network-
based analysis. Those areas that develop such an alternate procedure
are invited to apply to the conformity pilot program, proposed on July
9, 1996. Given the pilot program's purposes to allow greater
flexibility in implementing the rule and to evaluate potential
improvements to the rule, the pilot program is an appropriate vehicle
for this flexibility.

[[Page 43796]]

XI. Consequences of SIP Disapproval

A. Description of the Rule

EPA is finalizing the primary option in the proposal, which is the
option for which the regulatory text was proposed. In today's final
rule, EPA is also clarifying the definition of a protective finding.
Consequences of SIP disapproval apply when control strategy SIPs are
disapproved. Control strategy SIPs are 15% SIPs, post-1996 SIPs, and
attainment demonstrations.
1. Disapproval With a Protective Finding
When disapproving a control strategy SIP revision, EPA may give the
SIP a protective finding. If EPA disapproves a SIP but gives a
protective finding, the motor vehicle emissions budget in the
disapproved SIP could still be used to demonstrate conformity. There
would be no adverse conformity consequences unless highway sanctions
were imposed, as is the case with respect to all other SIP planning
failures. Highway sanctions would be imposed two years following EPA's
disapproval if the SIP deficiency had not been remedied. The conformity
of the plan and TIP would lapse once highway sanctions were imposed.
EPA would give a protective finding where a submitted SIP contains
adopted control measures or written commitments to adopt enforceable
control measures that fully satisfy the emissions reductions
requirements relevant to the statutory provision for which the SIP was
submitted, such as reasonable further progress (RFP) or attainment.
That is, EPA would give such a submitted SIP a protective finding if it
contains enough emissions reduction measures or commitments to these
measures to achieve its purpose of either demonstrating RFP or
attainment. Like the November 1993 rule, a SIP could receive a
protective finding even if all control measures are not fully adopted
in enforceable form, provided there are written commitments to such
measures. EPA would not give a protective finding to a SIP whose
emission reduction measures or commitments are inadequate to achieve
the required RFP or attainment.
2. Disapproval Without a Protective Finding
In the cases where EPA disapproves a SIP and does not give it a
protective finding, an area has a 120-day grace period, after which the
only transportation projects that could be found to conform would be
those included in the first three years of the currently conforming
transportation plan and TIP. No new plans, TIPs, or plan/TIP amendments
could be found to conform after the grace period. Further, no
additional projects not already in the first three years of the
currently conforming plan and TIP could be found to conform. Since
exempt projects and non-federal projects do not require conformity
determinations, they could proceed as long as they meet other
applicable requirements of the conformity rule (for example, a
regionally significant non-federal project must have been included in
the regional emissions analysis supporting the most recent plan and TIP
conformity determination).
If any one phase of a project is included in the first three years
of the currently conforming plan/TIP, all subsequent phases could
proceed following a disapproval, provided that all phases of the
project were included in the plan/TIP conformity analysis and all other
applicable project-level conformity criteria were satisfied (e.g., hot-
spot re

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A97-20968. Public record. Not legal advice.