Document ID: EPA_FRDOC_0001-26307
Agency: epa
Document Type: Notice
Title: Official Release of the MOVES3 Motor Vehicle Emissions Model for State Implementation Plans and Transportation Conformity
Posted Date: 2021-01-07T05:00Z

[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)).
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    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