Official Release of the MOVES3 Motor Vehicle Emissions Model for SIPs and Transportation Conformity

Official Release of the MOVES3 Motor Vehicle Emissions Model for SIPs and Transportation Conformity

Official Release of the MOVES3 Motor Vehicle Emissions Model for SIPs and Transportation Conformity

Karl J. Simon
Environmental Protection Agency
7 January 2021

[Federal Register Volume 86, Number 4 (Thursday, January 7, 2021)]
[Notices]
[Pages 1106-1110]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-00023]

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ENVIRONMENTAL PROTECTION AGENCY

[FRL-10016-84-OAR]

Official Release of the MOVES3 Motor Vehicle Emissions Model for
SIPs and Transportation Conformity

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability.

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SUMMARY: The Environmental Protection Agency (EPA) is announcing the
availability of the MOtor Vehicle Emission Simulator model (MOVES3) for
official purposes outside of California. MOVES3 is the latest state-of-
the art upgrade to EPA's modeling tools for estimating emissions from
cars, trucks, buses, and motorcycles based on the latest data and
regulations. MOVES3 is available for use in state implementation plans
(SIPs) and transportation conformity analyses outside of California.
This notice starts a two-year grace period before MOVES3 will need to
be used as the latest EPA emissions model in new regional emissions
analyses and a two-year grace period before MOVES3 will need to be used
in new hot-spot analyses for transportation conformity determinations
outside of California.

DATES: EPA's announcement of the MOVES3 emissions model for SIPs and
transportation conformity analyses in states other than California is
effective January 7, 2021. This announcement starts a two-year
transportation conformity grace period that ends on January 9, 2023.
After this date, MOVES3 will need to be used as the latest EPA
emissions model in both regional emissions analyses and in hot-spot
analysis for new transportation conformity analyses outside of
California.

FOR FURTHER INFORMATION CONTACT: For technical model questions
regarding the official release or use of MOVES3, please email EPA at
mobile@epa.gov. For questions about SIPs, contact Rudy Kapichak at
Kapichak.Rudolph@epa.gov, 734-214-4574. For transportation conformity
questions, contact Astrid Terry at Terry.Astrid@epa.gov, 734-214-4812.

SUPPLEMENTARY INFORMATION: The contents of this notice are as follows:

I. General Information
II. What is MOVES3?
III. SIPs and MOVES3
IV. Transportation Conformity and MOVES3

I. General Information

A. Does this action apply to me?

Entities potentially impacted by the approval of MOVES3 are those
that adopt, approve, or fund transportation plans, transportation
improvement programs (TIPs), or projects under title 23 U.S.C. or title
49 U.S.C. Chapter 53 and those that develop and submit SIPs to EPA.
Regulated categories and entities affected by today's action include:

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Category Examples of regulated entities
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Local government....................... Local air quality and
transportation agencies,
including metropolitan
planning organizations (MPOs).
State government....................... State air quality and
transportation agencies.
Federal government..................... Department of Transportation
(Federal Highway
Administration (FHWA) and
Federal Transit Administration
(FTA)).
------------------------------------------------------------------------

This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by the
release of MOVES. Other entities not listed in the table could also be
affected. To determine whether your organization is affected by this
action, you should carefully examine the transportation conformity
applicability requirements in 40 CFR 93.102. If you have questions
regarding the applicability of this action to a particular entity,
consult the persons listed in the preceding FOR FURTHER INFORMATION
CONTACT section.

B. How can I get copies of MOVES3 and other related information?

The official version of the MOVES3 model, along with user guides
and supporting documentation, are available on EPA's MOVES website:
www.epa.gov/moves. Individuals who wish to receive EPA announcements
related to the MOVES3 model should subscribe to the EPA-MOBILENEWS
email listserv, which can be done at EPA's website at: www.epa.gov/moves/forms/epa-mobilenews-listserv.
Available guidance on how to apply MOVES3 for SIPs and
transportation conformity purposes can be found on EPA's transportation
conformity website, www.epa.gov/state-and-local-transportation/policy-
and-technical-guidance-state-and-local-

[[Page 1107]]

transportation,\1\ including ``Policy Guidance on the Use of MOVES3 for
State Implementation Plan Development, Transportation Conformity,
General Conformity, and Other Purposes'' (EPA-420-B-20-044, November
2020).\2\
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\1\ Interested parties can find these documents under either the
``Emission Models and Conformity'' or ``Project-Level Conformity''
topics on this website.
\2\ This guidance, along with the other EPA guidance referenced
in this document, is listed in the EPA guidance portal at
www.epa.gov/guidance/guidance-documents-managed-office-air-and-radiation.
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EPA will continue to update these websites as other MOVES support
materials and guidance are developed or updated.

II. What is MOVES3?

MOVES3 is EPA's latest motor vehicle emissions model for state and
local agencies to estimate volatile organic compounds (VOCs), nitrogen
oxides (NOx), particulate matter (PM2.5 and
PM10), carbon monoxide (CO), and other precursors from cars,
trucks, buses, and motorcycles for SIP purposes and conformity
determinations outside of California.\3\ The model is based on analyses
of millions of emission test results and considerable advances in the
Agency's understanding of vehicle emissions.
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\3\ MOVES can also model emissions in the District of Columbia,
Puerto Rico, and the U.S. Virgin Islands. Nonattainment and
maintenance areas located in California use the latest approved
version of the Emission FACtor (EMFAC) model.
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The first model in the MOVES series, called MOVES2010, was released
in December of 2009. MOVES2010 was followed by two minor updates,
MOVES2010a and MOVES2010b. Both of these minor MOVES2010 revisions
enhanced model performance. MOVES2014, released in 2014, was a major
revision to MOVES2010b and included new data, new emissions standards,
and new functional improvements and features. It incorporated
substantial new data for emissions, fleet, and activity developed since
the release of MOVES2010. MOVES2014 was also followed by two minor
updates, MOVES2014a and MOVES2014b.\4\
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\4\ In the remainder of this notice, ``MOVES2014'' refers to all
of the MOVES2014 models: MOVES2014, MOVES2014a, and MOVES2014b.
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MOVES3 incorporates new regulations, features and significant new
data, as detailed in the MOVES3 technical reports. Notably, MOVES3
incorporates:
Improvements to heavy-duty (HD) diesel running emission
rates based on manufacturer in-use testing data from hundreds of HD
trucks;
Updated emission rates for HD gasoline and compressed
natural gas (CNG) trucks;
Updated light-duty (LD) vehicle emission rates for
hydrocarbons (HC), CO and NOx-based on in-use testing data;
Updated LD PM rates for Model Year (MY) 2004 and later,
incorporating data on gasoline direct injection engines;
New fuel characteristic data from EPA fuel compliance
submissions;
Updated fuel effect calculations to better characterize
the base fuel used to develop LD base emission rates;
The effects of the HD Phase 2 GHG rule; \5\
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\5\ 81 FR 7348, October 25, 2016.
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The effects of the Safer Affordable Fuel-Efficient (SAFE)
Vehicles Rule on light-duty fuel economy; \6\
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\6\ 85 FR 24174, April 30, 2020.
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``Off-network idle'' emissions beyond the idling that is
already considered in the MOVES drive cycles; and
Several improvements to the MOVES interface, user inputs
and outputs.
MOVES3 also includes a variety of activity updates, most notably:
Vehicle start and idling activity patterns are based on
real-world instrumented vehicle data collected by a telecommunications
company for LD vehicles and the Department of Energy's (DOE) National
Renewable Energy Lab (NREL) for HD vehicles;
Default hotelling activity has been substantially reduced
from what was included in MOVES2014 based on the NREL instrumented
truck data;
National vehicle miles travelled (VMT) and vehicle
population inputs have been updated with newer historical data from the
Federal Highway Administration (FHWA) and more recent forecasts from
DOE; and
National onroad vehicle default fuel, regulatory class,
and age distributions are based on newer vehicle registration data.
MOVES3 includes the capability to estimate vehicle exhaust and
evaporative emissions as well as brake wear and tire wear emissions for
criteria pollutants and precursors. However, MOVES3 does not include
the capability to estimate emissions of re-entrained road dust. To
estimate emissions from re-entrained road dust, practitioners should
continue to use the latest approved methodologies.\7\
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\7\ See EPA's notice of availability, ``Official Release of the
January 2011 AP-42 Method for Estimating Re-Entrained Road Dust from
Paved Roads,'' published in the Federal Register on February 4, 2011
(76 FR 6328).
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The structure of MOVES3 is fundamentally the same as MOVES2014,
although there are new format options for some inputs, and the model
run time may differ depending on the type of run and user inputs and
computer configuration. As for emissions, EPA performed a comparison of
MOVES3 to MOVES2014b using default information in MOVES3 at the
national level, and for two sample urban counties with different local
travel patterns and ambient conditions. In general, compared to
MOVES2014b, MOVES3 national emission estimates are slightly lower for
most criteria pollutants in future years. However, in the two sample
urban counties, NOX emissions estimates were higher in
future years. This is due to higher running emissions from heavy-duty
trucks outweighing declines from heavy-duty hotelling. Note that
results will vary based on the pollutant selected and that area's local
inputs. Based on our testing, MOVES run time at the Default and County
Scale should be about the same or faster than runs with MOVES2014b. In
addition, MOVES3 run time at the Project Scale may be notably longer
compared to MOVES2014 depending on the type of run, user inputs and
computer configuration.

III. SIPs and MOVES3

EPA has articulated its policy regarding the use of MOVES3 in SIP
development in its ``Policy Guidance on the Use of MOVES3 for State
Implementation Plan Development, Transportation Conformity, General
Conformity and Other Purposes'' (EPA-420-B-20-044, November 2020).
Today's notice highlights certain aspects of the guidance, but state
and local governments should refer to the guidance for more detailed
information on how and when to use MOVES3 in reasonable further
progress SIPs, attainment demonstrations, maintenance plans, inventory
updates, and other SIP submissions.
MOVES3 should be used in ozone, CO, PM, and nitrogen dioxide
(NO2) SIP development as expeditiously as possible, as there
is no grace period for the use of MOVES3 in SIPs. The Clean Air Act
requires that SIP inventories and control measures be based on the most
current information and applicable models that are available when a SIP
is developed.\8\ However, EPA also

[[Page 1108]]

recognizes the time and level of effort that certain states may have
already undertaken in SIP development using a version of MOVES2014.
States should consult with their EPA Regional Office if they have
questions about how MOVES3 affects SIPs under development in specific
nonattainment or maintenance areas. Early consultation can facilitate
EPA's adequacy finding for SIP motor vehicle emissions budgets for
transportation conformity purposes or EPA's SIP approval.
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\8\ See Clean Air Act section 172(c)(3). Also see the discussion
of emissions inventory requirements in the ``Fine Particulate Matter
National Ambient Air Quality Standards: State Implementation Plan
Requirements'' rule (81 FR 58029, August 24, 2016) and in the
``Implementation of the 2015 National Ambient Air Quality Standards
for Ozone: Nonattainment Area State Implementation Plan
Requirements'' rule (83 FR 63022, December 6, 2018).
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States should use the latest version of MOVES that is available at
the time that a SIP is developed. All states other than California
should use MOVES3 for SIPs that will be submitted in the future so that
they are based on the most accurate estimates of emissions possible.
However, state and local agencies that have already completed
significant work on a SIP with a version of MOVES2014 (e.g., attainment
modeling has already been completed with MOVES2014) may continue to
rely on the earlier version of MOVES. It would be unreasonable to
require the states to revise these SIPs with MOVES3 since significant
work has already occurred based on the latest information available at
the time the SIP was developed, and EPA intends to act on these SIPs in
a timely manner.
The Clean Air Act does not require states that have already
submitted SIPs or will submit SIPs shortly after the release of a new
model to revise these SIPs simply because a new motor vehicle emissions
model is now available.\9\ States can choose to use MOVES3 in these
SIPs, for example, if it is determined that it is appropriate to update
motor vehicle emissions budgets (``budgets'') with the model for future
conformity determinations. However, as stated above, states should use
MOVES3 where SIP development is in its initial stages or has not
progressed far enough along that switching from a previous model
version would create a significant adverse impact on state resources.
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\9\ Sierra Club v. EPA, 356 F.3d. 296, 308 (DC Cir. 2004) (``To
require states to revise completed plans every time a new model is
announced would lead to significant costs and potentially endless
delays in the approval processes.'')
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Incorporating MOVES3 into the SIP now could assist areas in
mitigating possible transportation conformity difficulties in the
future after the MOVES3 conformity grace period ends. New regional
emissions analyses using EPA's emissions model that are started after
the grace period is over must be based on MOVES3 (40 CFR 93.111), so
having MOVES3-based SIP budgets in place at that time could provide
more consistency with transportation conformity determinations.

IV. Transportation Conformity and MOVES3

In today's notice, EPA is announcing the availability of MOVES3 for
use in transportation conformity analyses outside of California. EPA is
also establishing a two-year grace period before MOVES3 will need to be
used in regional emissions analysis for transportation conformity
determinations and in hot-spot analyses for project-level
transportation conformity determinations which use EPA's emissions
model. The MOVES3 grace period for regional emissions and hot-spot
analyses applies to the use of MOVES3 and any future minor revisions
that occur during the grace period.
Transportation conformity is a Clean Air Act requirement to ensure
that federally supported highway and transit activities are consistent
with (``conform to'') the SIP. Conformity to a SIP means that a
transportation activity will not cause or contribute to new air quality
violations; worsen existing violations; or delay timely attainment of
national ambient air quality standards or any interim milestones.
Transportation conformity applies in nonattainment and maintenance
areas for transportation-related pollutants: Ozone, CO,
PM2.5, PM10 and NO2. EPA's
transportation conformity regulations (40 CFR parts 51.390 and 93
Subpart A) describe how federally funded and approved highway and
transit projects meet these statutory requirements.
The remainder of this section describes how the transportation
conformity grace period was determined and summarizes how it will be
implemented, including those circumstances when the grace period could
be shorter than two years for regional emissions analyses. However, for
complete explanations of how MOVES3 is to be implemented for
transportation conformity, including details about using MOVES3 during
the grace period, refer to ``Policy Guidance on the Use of MOVES3 for
State Implementation Plan Development, Transportation Conformity,
General Conformity and Other Purposes'' (EPA-420-B-20-044).

A. Why is EPA establishing a two-year conformity grace period?

Section 176(c)(1) of the Clean Air Act states that ``. . .[t]he
determination of conformity shall 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. . .''.
Additionally, the transportation conformity rule (40 CFR 93.111)
requires conformity analyses to be based on ``the latest emissions
estimation model available,'' and further states that this requirement
is satisfied if the most current version of EPA's motor vehicle
emissions model is used. When EPA announces a new emissions model, such
as MOVES3, we establish a grace period before the model needs to be
used for transportation conformity purposes (40 CFR 93.111(b)). In
consultation with DOT, EPA must consider the degree of change in the
emissions model and the effects of the new model on the transportation
planning process (40 CFR 93.111(b)(2)). The transportation conformity
rule provides that EPA will establish a grace period for new emissions
models of between three and 24 months (40 CFR 93.111(b)(1)).
EPA articulated its intentions for establishing the length of a
conformity grace period in the preamble to the 1993 transportation
conformity rule (November 24, 1993; 58 FR 62211):
``EPA and DOT [the Department of Transportation] will consider
extending the grace period if the effects of the new emissions model
are so significant that previous SIP demonstrations of what emission
levels are consistent with attainment would be substantially affected.
In such cases, States should have an opportunity to revise their SIPs
before MPOs must use the model's new emissions factors.''
In consultation with DOT, EPA considered the degree of change in
MOVES3 and the effects of the new model on the transportation planning
process (40 CFR 93.111(b)(2)). EPA considered the time it will take
state and local transportation and air quality agencies to conduct and
provide technical support for analyses. State and local agencies will
need to become familiar with the MOVES3 emissions model and may need to
convert existing data for use in MOVES3. Since 1993, the fundamental
purpose of section 93.111(b) of the transportation conformity rule has
been to provide a sufficient amount of time for MPOs and other state
and local agencies to learn and employ new emissions models. The
transition to a new emissions model for conformity involves more than
learning to use the new model and preparing input data and model
output. After model start-up is complete, state and local agencies also
need to consider how the model affects regional emissions analysis
results and whether SIP and/or

[[Page 1109]]

transportation plan/TIP changes are necessary to assure future
conformity determinations.
The two-year conformity grace period also provides sufficient time
for state and local agencies to learn and apply new technical guidance
and training courses that reflect MOVES3. EPA is working to update
guidance documents and training courses as quickly as possible. EPA
will notify MOVES3 users when these important materials are available.
Training courses are anticipated to be provided in the form of webinars
and other courses and address different levels of State and local
expertise.
In addition, many agencies will be implementing the transition to
PM and CO hot-spot analyses with MOVES3 for applicable projects in
those nonattainment and maintenance areas, with each analysis
potentially involving multiple state and local agencies. States with CO
hot-spot protocols that were previously approved into the SIP (40 CFR
93.123(a)(1)) that are based on a previous model will need time to
revise them. Additional time is necessary to revise previously approved
CO hot-spot protocols, and the SIP revision process and state
requirements can vary. Finally, EPA considered the general time and
monetary resource constraints in which state and local agencies
currently operate. Upon considerations of all these factors, EPA is
establishing a two-year grace period, which begins today and ends on
January 9, 2023, before MOVES3 needs to be used for new transportation
conformity analyses outside of California.

B. Circumstances When Grace Period Will Be Shorter Than Two Years

The grace period for regional emissions analyses will be shorter
than two years for a given pollutant if an area revises its SIP and
motor vehicle emissions budgets with MOVES3 and such budgets have been
found adequate or approved into the SIP prior to the end of the two-
year grace period. In this case, the new regional emissions analysis
must use MOVES3 if the conformity determination is based on a MOVES3-
based budget (40 CFR 93.111).
Areas that are designated nonattainment or maintenance for multiple
pollutants may rely on both MOVES3 and MOVES2014 to determine
conformity for different pollutants during the grace period. For
example, if an area revises a previously submitted (but not approved)
MOVES2014-based PM10 SIP with MOVES3 and EPA finds these
revised MOVES3 budgets adequate for conformity, such budgets would
apply for conformity on the effective date of the Federal Register
notice announcing EPA's adequacy finding. In this example, if the area
is nonattainment for PM10 and ozone, the MOVES3 grace period
would end for PM10 regional emissions analyses once EPA
found the new MOVES3-based SIP budgets adequate. However, MOVES2014
could continue to be used for ozone-related regional emissions analyses
begun before the end of the MOVES3 grace period.\10\ In addition, the
length of the grace period for hot-spot analyses would not be affected
by an early submission of MOVES3-based budgets. In this example, the
two-year grace period for PM10 hot-spot analyses would
continue to apply even if the grace period is shortened for regional
PM10 conformity analyses. EPA Regional Offices should be
consulted for questions regarding such situations in multi-pollutant
areas.
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\10\ In this example, such an area would use MOVES3 to develop a
regional emissions analysis for PM10 for comparison to
the revised MOVES3-based budgets (e.g., PM10 budgets).
The regional emissions analysis for ozone could be based on
MOVES2014 for the VOC and NOx budgets in the ozone SIP for the
remainder of the conformity grace period.
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In addition, in most cases, if the state revises previously
approved budgets based on an earlier EPA emissions model, the revised
MOVES3 budgets could not be used for conformity purposes until EPA
approves them, i.e., approves the SIP revision. In general, submitted
SIPs cannot supersede approved budgets until the submitted SIP is
approved. See 40 CFR 93.118(e)(1).
However, 40 CFR 93.118(e)(1) allows an approved budget to be
replaced by an adequate budget if EPA's approval of the initial budgets
specifies that the budgets being approved may be replaced in the future
by new adequate budgets. This flexibility has been used in limited
situations in the past. In such cases, the MOVES3-based budgets would
be used for conformity purposes once they have been found adequate, if
requested by the state in its SIP submission and specified in EPA's SIP
approval. States should consult with their EPA Regional Office to
determine if this flexibility applies to their situation.

C. Use of MOVES3 for Regional Emissions Analyses During the Grace
Period

During the conformity grace period, areas should use interagency
consultation to examine how MOVES3 will impact their future
transportation plan and TIP conformity determinations, including
regional emissions analyses. Isolated rural areas should also consider
how future regional emissions analyses will be affected when the MOVES3
grace period ends. Areas should carefully consider whether the SIP and
budgets should be revised with MOVES3 or if transportation plans and
TIPs should be revised before the end of the conformity grace period,
since doing so may be necessary to ensure conformity in the future.
Finally, the transportation conformity rule provides flexibility
for completing conformity determinations based on regional emissions
analyses that use MOVES2014 that are started before the end of the
grace period. Regional emissions analyses that are started during the
grace period can use either MOVES2014 or MOVES3. The interagency
consultation process should be used if it is unclear if a MOVES2014-
based analysis was begun before the end of the grace period. If there
are questions about which model should be used in a conformity
determination, the EPA Regional Office can be consulted.
When the grace period ends on January 9, 2023, MOVES3 will become
the only EPA motor vehicle emissions model for regional emissions
analyses for transportation conformity in states other than California.
In general, this means that all new transportation plan and TIP
conformity determinations started after the end of the grace period
must be based on MOVES3, even if the SIP is based on MOVES2014 or an
older version of the MOVES model.

D. Use of MOVES3 for Project-Level Hot-Spot Analyses During the
Conformity Grace Period

The MOVES3 grace period also applies to the use of MOVES3 for CO,
PM10 and PM2.5 hot-spot analyses. Sections 93.116
and 93.123 of the transportation conformity regulation contain the
requirements for when a hot-spot analysis is required for project-level
conformity determinations.\11\ The transportation conformity rule
provides flexibility for analyses that are started before the end of
the grace period. A conformity determination for a transportation
project may be based on a previous model if the analysis was begun
before or during the grace period, and if the final environmental
document for the project is issued no more than

[[Page 1110]]

three years after the issuance of the draft environmental document (40
CFR 93.111(c)). Interagency consultation should be used if it is
unclear if a previous analysis was begun before the end of the grace
period. For CO, PM10 and PM2.5 hot-spot analyses
that start during the grace period, project sponsors can choose to use
MOVES2014 or MOVES3.
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\11\ In CO nonattainment and maintenance areas, a hot-spot
analysis is required for all non-exempt projects, with quantitative
hot-spot analyses being required for larger, congested intersections
and other projects (40 CFR 93.123(a)(1)). In addition, in
PM2.5 and PM10 nonattainment and maintenance
areas, the transportation conformity regulation requires that a
quantitative hot-spot analysis be completed for certain projects
(see 40 CFR 93.123(b)(1)).
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EPA encourages sponsors to use the consultation process to
determine which option may be most appropriate for a given situation.
Any new CO, PM10 or PM2.5 hot-spot analyses for
conformity purposes begun after the end of the grace period must be
based on MOVES3. EPA has guidance on how to conduct quantitative
PM2.5 and PM10 hot-spot modeling for
transportation conformity purposes, and on how to use MOVES for a CO
hot-spot analysis. EPA will be updating these guidance documents with
MOVES3; until that time, the MOVES2014-based guidance may still
generally be used for MOVES3. See EPA's ``Project-level Conformity''
website, www.epa.gov/state-and-local-transportation/project-level-conformity-and-hot-spot-analyses, for the latest information and
guidance documents on how to conduct CO, PM10 and
PM2.5 hot-spot modeling for transportation conformity
purposes.
Any new, quantitative CO, PM10 or PM2.5 hot-
spot analysis for conformity purposes begun after the end of the grace
period using EPA's emissions model must use MOVES3. The interagency
consultation process should be used if it is unclear whether these
conditions are met. For questions about which model should be used in a
project-level conformity determination, consult with your EPA Regional
Office.

E. FHWA's CO Categorical Hot-Spot Finding

FHWA released the most recent CO categorical hot-spot finding for
intersection projects on July 17, 2017, that was based on
MOVES2014a.\12\ During the MOVES3 grace period, a project sponsor
outside of California may continue to rely on the categorical finding
for applicable projects that are determined through interagency
consultation to be covered by the finding's parameters. Any new CO hot-
spot analyses for conformity purposes begun after the end of the MOVES3
grace period may no longer rely on the July 2017 CO categorical hot-
spot finding because the finding was based on MOVES2014.
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\12\ See www.epa.gov/state-and-local-transportation/project-level-conformity-and-hot-spot-analyses#cohotspot.
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F. CO Hot-Spot Protocols That Were Previously Approved Into the SIP

Section 93.123(a)(1) of the transportation conformity regulation
allows areas to develop alternate procedures for determining localized
CO hot-spot analyses, when developed through interagency consultation
and approved by the EPA Regional Administrator. Some states have chosen
in the past to develop such procedures based on previous EPA emissions
models.
During the MOVES3 grace period, areas with previously approved CO
hot-spot protocols based on MOVES2014 may continue to rely on these
protocols. Once the MOVES3 two-year grace period ends, new CO hot-spot
analyses for conformity purposes will need to be based on MOVES3 and
thus may no longer rely on a CO hot-spot protocols based on MOVES2014.

Dated: November 24, 2020.
Karl J. Simon,
Director, Transportation and Climate Division, Office of Transportation
and Air Quality.
[FR Doc. 2021-00023 Filed 1-6-21; 8:45 am]
BILLING CODE 6560-50-P