Questions and Answers

EPA Releases MOVES2010a Mobile 

Source Emissions Model Update: 

Questions and Answers 

What is MOVES2010a? 

MOVES2010a, released in August 2010, is a minor update to MOVES2010. 

MOVES2010, released in December 2009, is EPA’s state-of-the-art tool for estimating 

emissions from highway vehicles. The model is based on analysis of millions of emission 

test results and considerable advances in the Agency’s understanding of vehicle 

emissions. As EPA has stated in the past, the advanced software used for MOVES 

allows EPA to easily incorporate new information. EPA is now releasing MOVES2010a 

to allow MOVES users to easily account for emissions under new car and light truck 

energy and greenhouse gas standards and to benefit from several improvements to 

MOVES general performance. 

What has changed from MOVES2010 to MOVES2010a? 

MOVES2010a incorporates new car and light truck greenhouse gas emissions standards 

affecting model years 2012-and-later (published May 7, 20101

) and updates effects of 

corporate average fuel economy standards affecting model years 2008-2011.2 MOVES2010a includes reductions in greenhouse gases associated with those standards in 

future calendar years, and small reductions in refueling and sulfur-related emissions 

associated with the reductions in vehicle fuel consumption. 

MOVES2010a also includes a number of other improvements. These are listed in 

Appendix A. The net impact of these changes on criteria pollutant emissions is small, 

with decreases of one percent or less in NOx, PM2.5, and CO emissions for regional 

inventory runs using example local inputs. Compared to MOVES2010, most regional 

inventory runs should see an increase in methane emissions and a small decrease 

(less than five percent using example local inputs) in the associated Volatile Organic 

Compound (VOC) and air toxics emissions. However, comparisons for runs that 

focus on a particular project or sourcetype may vary. 

1 www.regulations.gov/search/Regs/home.html#documentDetail?R=0900006480ae8a38 2 www.regulations.gov/search/Regs/home.html#documentDetail?R=09000064802cefcd and 

www.regulations.gov/search/Regs/home.html#documentDetail?R=09000064809375ea 

Office of Transportation and Air Quality 

EPA-420-F-10-050 

August 2010 
Questions and Answers 

When should MOVES2010a be used for state implementation plans and transportation 

conformity analyses? 

Because the impact of the changes in MOVES2010 on criteria pollutant emissions are small, we 

are not considering MOVES2010a a new emissions model for state implementation plan (SIP) 

and transportation conformity purposes under 40 CFR 93.111, and there will be no new grace 

period for regional conformity analyses using MOVES2010a. The MOVES2010 grace period for 

regional conformity analyses will apply to the use of MOVES2010a as well. It is important to 

note that EPA has not yet approved any version of MOVES for use in project-level conformity 

analyses, and will do so in the future when applicable conformity guidance is completed. 

All states other than California should use MOVES2010a for future SIPs in order to take full 

advantage of the improvements incorporated in this version. However, state and local agencies 

that have already completed significant work on a SIP with MOVES2010 can continue to use it. 

To determine when to use MOVES2010a in transportation conformity determinations, refer to 

the March 2, 2010 Federal Register notice which announced the grace period for MOVES2010 

(75 FR 9411) and the EPA’s policy guidance on the use of MOVES2010 for SIP development 

and transportation conformity (www.epa.gov/otaq/models/moves/420b09046.pdf). EPA’s existing 

guidance on the use of MOVES2010 for SIPs and conformity applies to MOVES2010a as well. 

We will work with state and local agencies to resolve any questions that come up regarding 

differences in MOVES2010 and MOVES2010a. 

What needs to be done to switch from using MOVES2010 to MOVES2010a? 

Instructions for downloading and installing MOVES2010a are available on the MOVES web 

page www.epa.gov/otaq/models/moves/ . Users will find that runspecs and input databases 

developed with MOVES2010 may need modification to be able to run with MOVES2010a. 

Users should regenerate fuelFormulation input files and Alternate Vehicle Fuels & Technologies 

(AVFT) strategy files. Output databases will need to be recreated with a new name since several 

new tables have been added. Users should always specify what version of MOVES was used to 

create emissions results. 

What other resources are available that apply to MOVES2010a? 

The latest version of EPA’s existing Technical Guidance for MOVES2010 (available at 

www.epa.gov/otaq/models/moves/420b10023.pdf) also applies to MOVES2010a. The 

MOVES2010 User Guide has been updated to reflect changes in MOVES2010a. The document 

“EPA Releases MOVES2010 Mobile Source Emissions Model: Questions and Answers” 

(available at: www.epa.gov/otaq/models/moves/420f09073.pdf) contains general information 

about the release of MOVES2010 that also applies to MOVES2010a. 

If you have technical questions about MOVES2010a, please contact the MOVES team at 

mobile@epa.gov. If you have SIP or conformity policy questions, please contact Rudy Kapichak 

(kapichak.rudolph@epa.gov) or Meg Patulski (patulski.meg@epa.gov). 

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Appendix A 

Changes from MOVES2010 to MOVES2010a 

Change from MOVES2010 to 

MOVES2010a 

Implication 

1) Updated light duty energy and carbon Reduced energy consumption and carbon dioxide 

dioxide rates and algorithm to account for emissions for light duty gasoline vehicles; reduced 

new fuel economy/CO2 regulations. hydrocarbon emissions from refueling and sulfate 

emissions from fuel consumption. 

2) Incorporated all data corrections 

distributed in May 15, 2010 version of the 

MOVES database (i.e. data in 

MOVESDB20100515). See MOVES2010 

Errata/Information Sheet (May 15, 2010) 

for additional information. 

For users who have switched to the May 15, 2010 

database, these changes will have no impact. 

Compared to MOVES2010 as released in 

December 2009, MOVES2010a will change NO 

and NO2 emissions (no change in NOx), decrease 

hydrocarbon evaporative emissions slightly, 

change diesel vehicle volatile organic compound 

(VOC) and air toxics emissions for calendar years 

1999-2006, change hydrocarbon emissions for 

vehicles running on gasoline containing ethanol in 

calendar years 1999-2004, and reduce particulate 

matter emissions for 2021-and-later light-duty 

diesel emissions. 

3) Improved algorithm for brakewear and Reduced brakewear and tirewear emissions. 

tirewear so emissions are always zero at Change is very small for regional inventories, but 

idle. larger for projects with substantial idling on steep 

grades. 

4) Improved MOVES algorithm for Negligible changes for regional emissions 

calculating emissions on ramps. calculated using Inventory mode (emissions 

inventory output). Increase in emissions on 

highways (restricted access roadtypes) for those 

using Emission Rate mode (rate-per-distance 

emissions). 

5) Improved methane algorithm and 

updated methane rates. Better accounts for 

methane variation with temperature, 

driving activity, etc. Adds methane 

emissions for some processes where it was 

not calculated. 

Methane emissions increased substantially. VOC 

and other non-methane hydrocarbons are reduced 

by about 3 to 5 percent. “Carbon Dioxide 

Equivalent” emissions are increased less than 1 

percent by this change and when combined with 

the impact of the new regulations (see above), total 

greenhouse gas emissions decline. 

When methane output is desired, users now must 

calculate total hydrocarbons also. 

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Change from MOVES2010 to 

MOVES2010a 

Implication 

6) Fixed error that reduced temperature 

correction for temperatures greater than 

100F. 

Increases hydrocarbon, CO, and NOx emissions 

for temperatures greater than 100F. Users who 

have modeled days with temperatures over 100F 

should evaluate emission changes that result from 

this revision. 

7) Fixed error in pre-aggregation by month 

that occurred in some HD runs. 

Some runs will see an increase in emissions for 

medium and heavy duty trucks and buses for VOC 

and other hydrocarbons. 

8) Repaired an error in the ammonia 

emissions calculations. 

Increases ammonia emissions for passenger and 

light commercial trucks. 

9) Improved calculation of air toxics 

emissions, particularly for diesel vehicles. 

Increases air toxic emissions from diesel vehicles. 

10) Updated default national heavy truck 

and bus sales-growth and VMT-growth 

factors to account for more recent data and 

updated projections. 

Increased default population, sales and emissions 

for buses and heavy trucks. This does not affect 

emissions in runs using local inputs for bus and 

truck populations. 

11) Fixed errors in motorcycle scrappage, 

migration and sales growth defaults. 

Increases default population of motorcycles. This 

does not affect emissions in runs using local inputs 

for motorcycle populations. 

12) Fixed error that increased emissions 

when users selected "placeholder" fuel. 

Reduces emissions, sometimes substantially, in 

runs where “Placeholder fuel” was selected. Even 

with MOVES2010a, use of “Placeholder” fuel is 

not recommended. 

13) Added a new output option -- emission 

rates by SCC. 

Eliminates some users’ need to calculate SCC rates 

in post-processing. Adds an additional column to 

emission rate output tables. 

14) Changed units for project-level start & 

extended idle rates (see Users Guide). 

Users may need to modify post-processing to 

apply rates properly. 

15) Improved MOVES user interface, 

including run spec editor, importers, 

summary reporter and "Multiple Run Spec 

Creator." 

Many small changes that should make MOVES 

easier to use. 

16) Improved error checking in MOVES 

importers. 

A number of changes that should make MOVES 

easier to use. 

17) Allow the batch creation of import 

databases. 

Makes it easier for users to create a group of 

similar import databases. 

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Change from MOVES2010 to 

MOVES2010a 

Implication 

18) Allow user to add new fuel 

formulations rather than just editing 

existing formulations. 

Provide more flexibility for users changing default 

fuel characteristics. 

19) Made MOVES more compatible with 

UNIX/Linux. 

Makes it easier to adapt MOVES to run with 

UNIX/Linux systems. While EPA does not have 

the resources to provide or fully support such 

adaptations, we encourage Linux/UNIX users to 

contact us to share information. 

20) Updated the “Example” files 

distributed with MOVES. 

Example file runs correctly with MOVES2010a. 

21) Improved MOVES run time and added 

tools to better monitor MOVES 

performance. 

MOVES runs slightly faster and users can better 

diagnose performance problems. 

22) Improved MOVES robustness by 

adding additional error checking. 

Improved code that sometimes led to MOVES 

crashes. 

23) Improved Custom Domain functioning. Allow users to calculate Custom Domain 

emissions for “off-network” roadtype without 

requesting output for other roadtypes. 

24) Corrected a problem in which 

evaporative permeation emissions were not 

always aggregated correctly. Previous 

output sometimes had rows with duplicate 

key fields. Depending on the postprocessing method used, totals could have 

been miscalculated. 

More accurate post-processing. 

25) Made the “DecodeMOVESOutput” 

script compatible with new version of 

MOVES. 

Decode script should run without error. 

26) Corrected several other minor errors in 

the MOVES program. 

Negligible impact on emissions. 

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