SUPPLEMENTARY INFORMATION:

Preamble acronyms and abbreviations. Throughout this preamble, the use of “we,” “us,” or “our” is intended to refer to the EPA. We use multiple acronyms and terms in this preamble. While this list may not be exhaustive, to ease the reading of this preamble and for reference purposes, the EPA defines the following terms and acronyms here:

ACT Advanced Clean Trucks

CO Carbon Monoxide

CAA Clean Air Act

CFR Code of Federal Regulations

CNG Compressed Natural Gas

DOE Department of Energy

DOT Department of Transportation

EMFAC EMissions FACtors

EPA Environmental Protection Agency

EV Electric Vehicle

FHWA Federal Highway Administration

FR Federal Register

FTA Federal Transit Administration

GHG Greenhouse Gas

HC Hydrocarbons

MPO Metropolitan Planning Organization

MOVES MOtor Vehicle Emission Simulator

MY Model Year

NAAQS National Ambient Air Quality Standards

NO₂  Nitrogen Dioxide

NO_X  Nitrogen Oxides

PM Particulate Matter

TIP Transportation Improvement Program

SIP State Implementation Plan

VMT Vehicle Miles Traveled

VOC Volatile Organic Compounds

Table of Contents

I. General Information

II. What is MOVES6?

III. SIPs and MOVES6

IV. Transportation Conformity and MOVES6

I. General Information

A. Does this action apply to me?

Entities potentially impacted by the approval of MOVES6 are those that adopt, approve, or fund transportation plans, transportation improvement programs (TIPs), or transportation projects as defined in 40 CFR 93.101 and those that develop and submit SIPs to the EPA. Regulated categories and entities potentially affected by this action include:

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 MOVES6 and other related information?

The official version of the MOVES6 model and supporting documentation are available on the EPA's MOVES website at: www.epa.gov/​moves. Individuals who want to receive EPA announcements related to the MOVES6 model can follow instructions linked from the MOVES website at: www.epa.gov/​moves/​latest-version-motor-vehicle-emission-simulator-moves to receive EPA email announcements related to MOVES and MOVES guidance.

Available guidance on how to apply MOVES6 for SIPs and transportation conformity purposes can be found on the EPA's transportation conformity website, www.epa.gov/​state-and-local-transportation/​policy-and-technical-guidance-state-and-local-transportation ,^[1] including the “MOVES6 Policy Guidance: Use of MOVES for State Implementation Plan Development, Transportation Conformity, General Conformity, and Other Purposes,” ^[2] referred to in this notice as the “MOVES6 Policy Guidance.” This website also includes the “MOVES6 Technical Guidance: Using MOVES to Prepare Emission Inventories in State Implementation Plans and Transportation Conformity.” ^[3]

The EPA will continue to update these websites as other MOVES support materials and guidance are developed or updated.

II. What is MOVES6?

MOVES6 is the EPA's latest official motor vehicle emissions model for State and local agencies to estimate volatile organic compounds (VOCs), nitrogen oxides (NO_X), particulate matter (PM_2.5 and PM₁₀ ), carbon monoxide (CO), and other pollutants and precursors from cars, trucks, buses, and motorcycles for SIP purposes and transportation conformity determinations other than California.^[4] MOVES6 represents the ( printed page 67567) sixth major release of the MOVES series of models.

MOVES is a flexible model using a variety of input and output options, allowing more than one way to develop emissions estimates. Like its predecessors, MOVES6 includes the capability to estimate criteria pollutant and precursor emissions from vehicle exhaust and evaporative emissions as well as brake wear and tire wear emissions. Also, like previous versions, MOVES6 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.^[5]

The EPA is releasing MOVES6 to account for important legislative and regulatory changes. On February 12, 2026, the EPA finalized the Endangerment Finding Rescission Rule that repealed all greenhouse gas (GHG) emission standards for light-, medium-, and heavy-duty on-highway vehicles and engines.^[6] MOVES6 accounts for this change and also accounts for the Congressional disapproval of the waiver for California's Advanced Clean Trucks (ACT) regulations.^[7] MOVES6 also accounts for legislation that reduced incentives for electric vehicles (EVs) and EV charging infrastructure.^[8]

Previous versions of the MOVES model ( i.e. , MOVES5 and MOVES4) both accounted for the GHG vehicle standards in effect at the time those models were released, projecting that GHG standards would be met through greater adoption of EVs over time.^[9] However, these GHG standards have since been rescinded.^[10] In MOVES6, the EPA updated energy consumption rates and adjusted assumptions about the fraction of EVs and other fuel types.^[11] MOVES6 still projects that some fraction of vehicles are EVs in future years, but these fractions by year are generally smaller than in MOVES5 and MOVES4. In addition, MOVES6 includes updated activity data and fixes incorrect values in MOVES5.

There are no changes to the MOVES interface since MOVES5. The significant changes in MOVES6 are summarized below:

• EV fractions were reduced to account for the repeal of GHG standards and reductions in incentives for EVs and EV infrastructure. Medium- and heavy-duty EV fractions were also reduced to account for Congressional disapproval of the waiver for California's ACT regulations that included heavy-duty zero emission vehicle requirements.
• Energy consumption rates for model year (MY) 2017-2024 were updated based on real-world data from the EPA's 2025 Automotive Trends Report.^[12] Rates for MY 2025 and later continued these trends.
• Historical and projected vehicle miles traveled (VMT) and vehicle populations were updated using the latest data on school buses and transit buses, as well as updated values from the U.S. Federal Highway Administration (FHWA) Highway Statistics (2024) and the DOE Annual Energy Outlook (2025).
• Emission rates were corrected to fix minor errors in MOVES5. The fixes affected exhaust hydrocarbon (HC), NO_X, and PM from MYs 2031 and later medium-duty (Class 2b and 3) trucks, CO from MYs 2027 and later light-duty cars and trucks, and tire wear from all compressed natural gas (CNG) heavy-heavy-duty (Class 8) trucks.
• Gasoline properties in a few counties were updated to account for new data and changes to local fuel requirements since MOVES5.

As a result of all these changes, estimates of emissions from MOVES6 may differ from earlier versions of MOVES. The net impact of these changes on estimated emissions will depend on many factors, including the specific area being modeled and the inputs used.

For additional information on the updates included in MOVES6, please refer to the “Overview of EPA's MOtor Vehicle Emission Simulator (MOVES6),” found at the EPA's MOVES website. Specific information about MOVES6 inputs and algorithms can be found on the EPA's websites for MOVES Onroad Technical Reports and MOVES Nonroad Technical Reports.^[13]

III. SIPs and MOVES6

The EPA has articulated the Agency's policy regarding the use of MOVES6 in SIP development in the MOVES6 Policy Guidance. This 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 MOVES6 in reasonable further progress SIPs, attainment demonstrations, maintenance plans, inventory updates, and other SIP submissions.

The Clean Air Act (CAA) and implementation rules for the National Ambient Air Quality Standards (NAAQS) describe how SIP inventories and control measures should be based on the most current information and applicable models available when a SIP is developed.^[14] Therefore, States should use the latest version of MOVES and planning assumptions available at the time that a SIP is developed to ensure the SIP is based on the most accurate estimates of emissions possible. Now that MOVES6 is available, it should be used in ozone, CO, PM, and nitrogen dioxide (NO₂) SIP development for all States other than California as expeditiously as possible, as there is no grace period for the use of MOVES6 in SIPs. For example, MOVES6 should be used if a State is in the early stages of SIP development and significant work has not yet occurred or if work has not yet started for a new SIP requirement.

The EPA also recognizes the time and level of effort involved in SIP development. In cases in which State and local agencies have already completed significant work on a SIP with MOVES5 or MOVES4 as of the MOVES6 release, they may continue to rely on this earlier version. For instance, SIP development may continue if a State has progressed far enough along that ( printed page 67568) switching from a previous model version would create a significant adverse impact on State resources ( e.g., if attainment modeling has already been completed with MOVES5 or MOVES4 prior to the MOVES6 release). However, as noted in section II of this notice, MOVES5 and MOVES4 contain national default EV projections that do not reflect the Endangerment Finding Rescission Rule or other updates in MOVES6. See sections 1.5 and 2.1 of the MOVES6 Policy Guidance for more information on using previous versions of MOVES in SIP development, including details on how to adjust EV projections in MOVES5 and MOVES4.

States should consult with their EPA Regional Office if they have questions about how MOVES6 affects SIPs under development in specific nonattainment or maintenance areas. Early consultation can facilitate the EPA's consideration of whether to make an adequacy finding for transportation conformity purposes as well as the Agency's consideration of a SIP submission.

The EPA does not require States to revise submitted SIPs or SIPs that have already been approved simply because a new motor vehicle emissions model is now available.^[15] States can, however, choose to update these SIPs with MOVES6, for example, if it is determined that it is appropriate to update motor vehicle emissions budgets (“budgets”) with the model for future transportation conformity determinations.^[16]

The EPA recognizes that States may have relied on the EV assumptions in MOVES5 and MOVES4 in SIP development based on the Agency's statements in previous versions of the MOVES Policy and Technical Guidance. The EPA expects limited cases in which State and local agencies have already completed significant work with MOVES5 or MOVES4 and submitted a SIP prior to or shortly after the Endangerment Finding Rescission Rule. When evaluating these SIP submittals, the EPA will consider the latest MOVES model, assumptions, and guidance information available to a State at the time it developed its SIP.

For complete explanations of how MOVES6 is to be implemented for SIP purposes, refer to the MOVES6 Policy Guidance.

IV. Transportation Conformity and MOVES6

Transportation conformity is required under CAA section 176(c) to ensure that federally funded or approved highway and transit activities are consistent with ( i.e., “conform to”) the purpose of the SIP. Conformity to the purpose of the SIP means that transportation activities will not cause or contribute to new air quality violations, worsen existing violations, or delay timely attainment of the relevant NAAQS or any interim milestones.^[17] The EPA's transportation conformity regulations establish the criteria and procedures for determining whether metropolitan transportation plans, TIPs, and federally supported highway and transit projects conform to the SIP.^[18] Transportation conformity applies to designated nonattainment and maintenance areas for transportation-related criteria pollutants: ozone, PM_2.5, PM₁₀, CO, and NO₂ .^[19]

The EPA has articulated the Agency's policy regarding the use of MOVES6 in transportation conformity determinations in the MOVES6 Policy Guidance. This 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 MOVES6 in transportation conformity determinations.

In this notice, the EPA is announcing the availability of MOVES6 for use in transportation conformity determinations other than California. The EPA is also establishing a two-year grace period before MOVES6 will be required for use in regional emissions analyses for transportation conformity determinations of transportation plans and TIPs and in hot-spot analyses for project-level transportation conformity determinations that use the EPA's emissions model.^[20] The MOVES6 grace period for regional emissions and hot-spot analyses applies to the use of MOVES6 and any future minor revisions that occur during the grace period.

This MOVES6 grace period is separate and distinct from the two-year grace period established with the release of the previous version of the model, MOVES5. The two-year grace period established by the EPA's December 2024 MOVES5 Notice of Availability in the Federal Register is unchanged by the release of MOVES6 and continues to be in effect until December 11, 2026.^[21]

The EPA also notes that MOVES6 includes the latest information for the national default projections of EVs, whereas the information in earlier versions of MOVES5 and MOVES4 needs to be updated for new or delayed analyses after the MOVES6 release.^[22] During the two-year MOVES6 grace period, modelers beginning new analyses with MOVES5 may not rely on MOVES5 national defaults for projections of EVs. See additional information below in sections IV.C. and D. of this notice and in the EPA's MOVES6 Policy Guidance.^[23]

The remainder of this section describes how the transportation conformity grace period was determined and summarizes how it will be implemented, including those circumstances in which the MOVES6 grace period could be shorter than two years for regional emissions analyses. However, for complete explanations regarding transportation conformity, refer to the MOVES6 Policy Guidance.

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

CAA section 176(c)(1) 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. . . .” ^[24] Additionally, the transportation conformity regulations require conformity determinations to be based on “the latest emission estimation model available,” and further state that this requirement is satisfied if the most current version of the EPA's motor vehicle emissions model is used in the conformity analysis.^[25] When the EPA announces a new emissions model, such as MOVES6, the Agency establishes a grace period before the model must be used for transportation conformity purposes.^[26] In consultation with the ( printed page 67569) U.S. Department of Transportation (DOT), the EPA must consider the degree of change in the emissions model and the effects of the new model on the transportation planning process.^[27] The transportation conformity regulations provide that the EPA will establish a grace period for new emissions models of between three and 24 months.^[28]

The EPA articulated its intentions for establishing the length of a grace period in the preamble to the 1993 transportation conformity rule:

“EPA and DOT 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.” ^[29]

In consultation with DOT, the EPA considered the degree of change in MOVES6 and the effects of the new model on the transportation planning process.^[30] The EPA considered the transition of State and local transportation and air quality agencies to conduct and provide technical support for analyses for MOVES6. Since 1993, the fundamental purpose of 40 CFR 93.111(b) of the transportation conformity regulations 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 involves preparing input data and model output as well as considering how the model affects regional emissions analysis results and whether SIP and/or transportation plan/TIP changes are necessary.

The EPA provides guidance on how to run the latest MOVES version for SIP and transportation conformity purposes with the release of the model.^[31] Generally, existing guidance and training applies to MOVES6 as noted on the EPA's website, and the Agency will notify MOVES6 users when updates to these materials are available. Training materials will continue to address different levels of State and local expertise.

Upon consideration of these factors, the EPA is establishing a two-year grace period, which begins today, October 27, 2026, and ends on October 27, 2028, before MOVES6 needs to be used for new transportation conformity analyses in States other than California.

B. Circumstances in Which the MOVES6 Grace Period Will Be Shorter Than Two Years

The MOVES6 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 MOVES6 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 MOVES6 because the transportation conformity determination would be demonstrating consistency with a MOVES6-based budget.^[32]

Areas designated nonattainment or maintenance for more than one pollutant may rely on both MOVES6 and MOVES5 to determine transportation conformity for different pollutants during the MOVES6 grace period. In addition, the length of the MOVES6 grace period for hot-spot analyses would not be affected by an early submission of MOVES6-based budgets. The appropriate EPA Regional Office should be consulted regarding situations in multi-pollutant areas.

C. Use of MOVES6 for Regional Emissions Analyses During the Grace Period

During the transportation conformity grace period, areas should use interagency consultation to examine how MOVES6 will impact their regional emissions analyses and future transportation plan and TIP conformity determinations.^[33] Areas should carefully consider whether the SIP and budget(s) should be revised with MOVES6 or if transportation plans and TIPs should be revised before the end of the grace period. The transportation conformity regulations also provide flexibility in that regional emissions analyses started with MOVES5 before or during the MOVES6 grace period can be completed using MOVES5.^[34]

It is also important that transportation conformity determinations continue to meet the requirements for using the latest planning assumptions.^[35] Under the transportation conformity regulations, the latest planning assumptions must be used when the conformity analysis begins, but if new information becomes available after that point, it does not need to be included unless a significant delay in the analysis occurs as determined through interagency consultation. As described in section II of this notice, MOVES6 incorporates applicable Federal vehicle standards, including the effects of the EPA's Endangerment Finding Rescission Rule as well as other updates that provide the latest information for the national default projections of EVs. Below is an overview for meeting the latest planning assumptions requirements during this model transition:

• For transportation conformity analyses started before the release of MOVES6, the national default EV projections in MOVES5 can be used by transportation agencies as part of their latest planning assumptions so long as the analysis has already begun (i.e., the analysis was started prior to the MOVES6 release) and there is no significant delay in the analysis.^[36]
• For transportation conformity determinations in which the analysis starts after the release of MOVES6, modelers must either update their MOVES5 modeling to include updated EV fraction projections or use MOVES6.

When the MOVES6 grace period ends, MOVES6 will replace MOVES5 as the latest EPA emissions model for all new transportation conformity analyses. State and local agencies are encouraged to transition sooner to MOVES6 to use the latest information and other model improvements. See sections 1.5 and 3.5 of the MOVES6 Policy Guidance for further details.

When the grace period ends on October 27, 2028, MOVES6 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 plans and TIP conformity determinations started after the end of the grace period must be based on MOVES6, even if the SIP is based on MOVES5 or an older version of the MOVES model.

D. Use of MOVES6 for Project-Level Hot-Spot Analyses During the Conformity Grace Period

The MOVES6 grace period also applies to the use of MOVES6 for CO, PM₁₀, and PM_2.5 hot-spot analyses. The transportation conformity regulations contain the requirements for when a hot-spot analysis is required for project- ( printed page 67570) level conformity determinations.^[37] The transportation conformity regulations provide flexibility for analyses 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 the end of the grace period and if the final environmental document for the project is issued no more than three years after the issuance of the draft environmental document.^[38]

Project-level transportation conformity determinations in which the hot-spot analysis has already begun ( i.e., the analysis was started prior to the MOVES6 release) with MOVES5 may have included the model's national default EV projections. These transportation conformity determinations may be completed because those EV projections were relied on as the most recent assumptions when the analysis began. For these conformity determinations, the interagency consultation process should be used to confirm when the analysis began, the EV projections used, and whether there is any delay in the analysis that would require new EV projections to be included.

For CO, PM₁₀, and PM_2.5 hot-spot analyses that start during the MOVES6 grace period, project sponsors can choose to use MOVES6 or MOVES5. If MOVES5 is used, modelers must update their MOVES5 modeling to include updated EV fraction projections. Any new CO, PM₁₀, or PM_2.5 hot-spot analyses for transportation conformity purposes begun after the end of the MOVES6 grace period must be based on MOVES6.

Interagency consultation must be used to evaluate and choose model(s) and associated methods and assumptions to be used in transportation conformity hot-spot analyses and regional emissions analyses.^[39] For questions about how the MOVES grace periods apply in a project-level conformity determination, contact your EPA Regional Office.

See the 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 for hot-spot analyses. See sections 1.5 and 3.7 of the MOVES6 Policy Guidance for further details.

91 FR 67565