Updates to the Greenhouse Gas and 

Energy Consumption Rates in 

MOVES2010a
Assessment and Standards Division

Office of Transportation and Air Quality

U.S. Environmental Protection Agency

Updates to the Greenhouse Gas and 

Energy Consumption Rates in 

MOVES2010a

NOTICE

This technical report does not necessarily represent final EPA decisions or 

positions. It is intended to present technical analysis of issues using data 

that are currently available. The purpose in the release of such reports is to 

facilitate the exchange of technical information and to inform the public of 

technical developments.

EPA-420-R-12-025

August 2012
Contents
 

1 Updates to Energy Rates and Sourcebin Distribution for MOVES2010a .............................. 2
 

1.1 Introduction ...................................................................................................................... 2
 

1.2 Background: Energy Rates in the MOVES model.......................................................... 3
 

1.3 Structural Changes: .......................................................................................................... 6
 

1.3.1 Updating the Database Sourcebinid Structure for Energy Rates .............................. 6
 

1.3.2 Converting MOVES2010 rates to the MOVES2010a structure ............................... 6
 

1.3.3 Changes to Engine Technologies.............................................................................. 8
 

1.4 Updating Energy Rates..................................................................................................... 8
 

1.5 Inventory Impacts of Changes relative to MOVES2010 ............................................... 13
 

2 Methane and N2O in MOVES2010...................................................................................... 16
 

Differences Between MOVES and "Sources and Sinks".......................................................... 16
 

2.1 Nitrous Oxide Emission Rates: ...................................................................................... 18
 

2.2 Methane Emission Rates:............................................................................................... 22
 

2.3 Alternative Fuels ............................................................................................................ 26
 

3 Updates to the Methane Rates for MOVES 2010a ............................................................... 28
 

1 
1 Updates to Energy Rates and Sourcebin Distribution for MOVES2010a 

1.1 Introduction 

MOVES is the U.S. Environmental Protection Agency's (EPA) Motor Vehicle Emission 

Simulator. It helps to answer "what if" questions, such as "How would particulate matter 

emissions decrease in my state on a typical weekday if truck travel was reduced during rush 

hour?" or "How does the total hydrocarbon emission rate change if my fleet switches to gasoline 

from diesel fuel?" The purpose of the tool is to provide an accurate estimate of emissions from 

mobile sources under a wide range of user-defined conditions. It is a state-of-the-art upgrade to 

EPA’s modeling tools for estimating emissions from highway vehicles, based on analysis of 

millions of actual emission test results and considerable advances in the Agency’s understanding 

of vehicle emissions. 

MOVES2010 was released in December of 2009. MOVES2010a was released in the 

summer of 2010 and updated MOVES2010. MOVES2010a incorporates new car and light truck 

greenhouse gas emissions standards affecting model years 2012 and later (published May 7, 

2010) and updates to the Corporate Average Fuel Economy (CAFE) standards affecting model 

years 2008 through 2011.1 MOVES2010a includes reductions in greenhouse gas emission rates 

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. This 

document details some of the updates for the MOVES2010a release. Specifically, the updates 

described in this document include: 

	 Updates to the MOVES database to reflect new data and projections for 2008 and 

newer light duty energy rates 

o	 Model year 2008-2010 vehicle data 

o	 Model year 2011 Fuel Economy (FE) final rule projections 

o	 Model year 2012-2016 FE/GHG final rule projections 

o Corrections to model year 2000+ light duty diesel energy start rates 

 Modifications to the organization of energy rates in MOVES database (DB) 

o	 Improved consistency between energy rates and remainder of MOVES 

o	 Redefined energy rate structure 

o	 Removed unused engine technologies from the MOVES DB 

o	 Removed unused emission rates from MOVES DB 

This report also documents the methane and nitrous oxide rates, and includes discussion 

of the changes made in MOVES2010a in the way that methane emissions are determined for all 

vehicle types and model years. 

This report assumes that the user is familiar with the MOVES model and its database 

design. A detailed knowledge of the emission rate structure may prove helpful to the reader. 

1 MOVES2010a, which only contains regulations that were final as of its release, does not reflect the impacts of 

Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and 

Vehicles (finalized in 2011) or the Proposed Rulemaking to Establish 2017 and Later Model Year Light-Duty 

Vehicle Greenhouse Gas Emissions and CAFE Standards (published in 2011). 

2 
Additional detail on MOVES is available on the MOVES technical background website 

(http://www.epa.gov/otaq/models/moves/movesback.htm). 

1.2 Background: Energy Rates in the MOVES model 

The energy rates in MOVES2010 were originally developed for MOVES2004, and are 

documented in “MOVES2004 Energy and Emission Inputs Draft Report” (EPA420-P-05-003). 

As documented in that report, EPA created the MOVES 2004 energy rates by analyzing second 

by second (1 Hz) resolution data from 16 EPA test programs covering approximately 500 

vehicles and 26 non-EPA test programs covering approximately 10,760 vehicles. “Holes” in the 

data were filled using either the Physical Emission Rate Estimator (PERE) 2 or interpolation. 

A partial timeline of the energy rates in MOVES is presented below. 

	 MOVES2004 

o	 Released with a full suite of energy rates to allow estimation of fuel 

consumption and GHG emissions. 

o	 Energy rates developed for fine detail of vehicle attribute and advanced 

technology, anticipating need for policy modeling (ex. “How does reducing 

vehicle weight affect energy consumption?”) 

o	 Documentation: MOVES2004 Energy and Emission Rate Inputs (Report: 

EPA420-P-05-003, February 2005) 

	 MOVES2010 

o	 Relatively minor updates from MOVES2004 

o	 Heavy Duty energy rates updated based on new scaled tractive power (STP) 

methodology 

o	 LD rates updated to include 2008-2011 model year 2011 Corporate Average 

Fuel Economy (CAFE) Standards for light trucks 

	 MOVES2010a 

o	 Light Duty energy rates updated substantively to account for CAFE model 

year 2011, LD GHG model year 2012-2016 standards 

o	 All energy rates updated structurally to greatly simplify MOVES' energy 

approach with focus on inventory development , rather than policy modeling 

As seen above, between MOVES 2004 and MOVES2010a, MOVES shifted being from a 

technology modeling tool to primarily serving as an inventory model. This shift was partially 

driven by the emergence of the EPA OMEGA (Optimization Model for reducing Emissions of 

Greenhouse gases from Automobiles) model.3 OMEGA, which EPA used in recent mobile 

source greenhouse gas (GHG) rulemakings, 4 estimates the technology cost and emission impacts 

of vehicle GHG standards. Many light duty energy policy questions no longer are estimated by 

2 Report: Fuel Consumption Modeling of Conventional and Advanced Technology Vehicles in the Physical 

Emission Rate Estimator (PERE) EPA420-P-05-001, February 2005

3 OMEGA web address: http://www.epa.gov/otaq/climate/models.htm 

OMEGA Version 1.3 documentation: EPA-420-B-10-042 

4 Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards; Final 

Rule: EPA-HQ-OAR-2009-0472-11424 

3 
EPA with the MOVES model, but rather with the more narrowly focused OMEGA model. At 

the same time, the MOVES model has become the official EPA model for estimating mobile 

source emissions in State Implementation Plans and conformity modeling.5 

Due to this change in scope, EPA reevaluated the structure of the energy rates for 

MOVES2010a. In MOVES, emission rates6 are defined by vehicle emission category 

(sourcebin) discriminators which describe combinations of vehicle attributes. MOVES allows 

different emission rates to be defined by different sourcebin discriminators; a given combination 

of pollutant and process can require any combination of the discriminators listed in Table 1-1. 

Table 1-1 – Sourcebin Discriminators 

Sourcebin Discriminators 

Fuel type 

Engine Technology 

Regulatory Class 

Model Year Group 

Engine Size 

Weight Class 

Ultimately, these discriminators are strung together in a rigidly defined format and are 

used as unique database keys in the “emissionrate” or “emissionratebyage” tables in MOVES. 

Not all source type/pollutant/process combinations require data for all sourcebinid components, 

and unused components of the sourcebinid can be left as zeros.7 Previous versions of MOVES, 

including MOVES2010, require that energy rates discriminate by all sourcebinid components 

other than regulatory class (Table 1-2). 

5 Policy Guidance on the Use of MOVES2010 and Subsequent Minor Revisions for State Implementation Plan 

Development, Transportation Conformity, and Other Purposes, April 2012, 

http://www.epa.gov/otaq/models/moves/documents/420b12010.pdf

6 The MOVES design treats energy consumption as an emission rate. Therefore, in this document, the term 

emissions is interchangeably used to refer to energy.

7 The table “sourcetypepolprocess” in the MOVES DB controls which components of the sourcebinid are required 

for each sourcetype, pollutant, and process combination. 

4 
Table 1-2 - MOVES 2004 Energy Sourcebin Discriminators 

This contrasts to the emission rates used for criteria pollutants, which use a broader set of 

criteria (Table 1-3). 

Table 1-3 – Contrasting Criteria Pollutants and Energy in MOVES2010 

Criteria Pollutants Energy 

Fuel type Fuel type 

Engine Technology Engine Technology 

Regulatory Class Regulatory Class 

Model Year Group Model Year Group 

Engine Size Engine Size 

Weight Class Weight Class 

Age Group Age Group 

Note: discriminators in bold, italic are used to classify that set of emissions in MOVES. 

In MOVES2010, heavy duty vehicle running energy consumption was restructured 

without engine size and weight class sourcebin discriminators.8 MOVES2010a extends this 

format to all combinations of sourcetypes and energy-related processes (start, running, extended 

idle). Removing two sourcebin discriminators significantly reduces the size of the database 

table, and pre-aggregating by engine size and vehicle weight shifts the size/weight calculations 

from MOVES onto external sources. A summary table of the changes to the energy sourcebin 

structure is presented below (Table 1-4). 

Table 1-4 – Changes to Energy Sourcebin Discriminators between MOVES2010 and 2010a 

Descriptors used in MOVES2010 Descriptors used in Moves2010a 

Fuel type Fuel type 

Model year group (decadal) Model year group (single year) 

Engine size Regulatory class 

Vehicle Weight 

Size and weight distribution by sourcetype 

Engine Technology 

8 Report: Development of Emission Rates for Heavy-Duty Vehicles in the Motor Vehicle Emissions Simulator 

MOVES2010 (EPA-420-B-12-049) 

5 
1.3 Structural Changes: 

1.3.1 Updating the Database Sourcebinid Structure for Energy Rates 

Seven database tables were changed to alter the sourcebin discriminators used for energy 

rates (Table 1-5). These changes aggregated the database so that size and weight were no longer 

distinguishing characteristics. The database was then re-disaggregated according to regulatory 

class. 

As part of this process, the number of engine technologies in the MOVES database was 

reduced. This change altered four additional database tables (Table 1-5). The MOVES2010 

engine technologies included hybrid varieties, fuel cell vehicles, and “advanced internal 

combustion” vehicles. These technologies were removed from the model, and the associated 

emission rates were removed from the emissionratebyage table. 

Table 1-5 – Summary of Database Changes required 

Table Name Change Summary 

1 datasource Added a new datasourceid that refers to this document. 

2 emissionrate Updated energy rates with new values and sourcebinids 

3 emissionratebyage Removed emission rates for enginetypeids other than 

conventional internal combustion (1) & electric (30) 

4 fuelengfraction Updated fuel and engine type combinations to remove 

enginetypes other than 1 & 30 

5 enginetech Removed engine technologies other than 1 & 30 

6 fuelengtechassoc Removed engine technologies other than 1 & 30 

7 pollutantprocessmodelyear Changed the energy polprocessids (9101,9102, 9190) to 

have single year modelyeargroupids (increase resolution of 

rates). 

8 regclassfraction Removed engine technologies other than 1 & 30. 

9 samplevehiclepopulation Reflects removal of sizeweightid and engine technologies 

(engtechid) 

10 sizeweightfraction Truncated 

11 sourcetypepolprocess Stopped requiring sizeweightid, and began requiring 

regclassid for energy polprocessids (9101, 9102, 9190) for 

all sourcetypes. 

1.3.2 Converting MOVES2010 rates to the MOVES2010a structure 

EPA created energy rates for the new sourcebin structure by aggregating the MOVES 

2010 energy rates by regulatory class. For those regulatory classes that were mapped to a single 

source type, the conversion between the MOVES2010 structure and the MOVES2010a structure 

was a 1:1 correspondence. For those sourcetypeids that mapped to several regulatory classes 

(Table 1-6), the methodology is described below. 

6 
Table 1-6 – Mapping between Sourceusetypes and Regulatory Classes 

SourcetypeID Possible Regulatory Classes 

11 10 

21 20 

31,32 30,41,42 

41,43,51,52,53,54,61,62 46,47 

42 46,48 

Information from the 1997 and 2002 Vehicle Inventory and Use Survey (VIUS) as 

aggregated in the MOVES2010 database table samplevehiclepopulation (SVP) was used as a 

mapping tool between regulatory class and source type. The SVP table specifies the distribution 

of each source type and model year combination across fuel type, engine technology, 

SCCVtypeID,9 engine size, vehicle weight, and regulatory class, with each row specifying a 

unique set of attributes. The SVP table was joined to the emissionrate table so that an additional 

column was added to the SVP with the corresponding MOVES2010 energy emission rate. This 

process was repeated for start rates, running rates, and extended idle rates. This produced a set 

of SVP tables, each with an additional emission rate column for the relevant process. 

In order to create emission rates by regulatory class, we weighted each emission rate 

attached to the SVP table using year 0 populations from the sourcetypeagepopulation table of the 

MOVES execution database. The sales for each source type model year combination were 

distributed to the appropriate row of the SVP using the SVP stmyfraction column. Using the 

sales-based weighting, the emission rates were aggregated by regulatory class, fuel type, and 

model year. For start rates, this process was executed for operating mode 108, which is a cold 

start. The other seven start operating modes are modifications of a cold start with different soak 

times. As in previous version of MOVES, soak time effects derived from a California Air 

Resources Board report on uncatalyzed hydrocarbon emissions10 were applied to develop the 

other seven operating modes (101,102, 103,104,105,106,107). 

For running rates, the process outlined above was necessary only for motorcycles, 

passenger cars, passenger trucks, and light commercial trucks. The running rates for other 

sourcetypes already had been set to be a single set of rates in MOVES2010.11 This process was 

repeated for each operating mode. 

In MOVES, only sourcetypeid 62 (long-haul combination truck) has extended idle 

operation. Therefore, both regulatory class 46 (Medium Heavy Duty (19.5K lbs < GVWR < 

33K lbs)) and regulatory class 47 (Heavy Heavy Duty (GVWR > 33K lbs)) were set to have the 

same extended idle rate as MOVES2010 sourcetypeid 62 vehicles. 

9 An SCCvtype, or source classification code vehicle type, is an alternative vehicle identification scheme which is 

used in the MOVES model. 

10 Methodology For Calculating And Redefining Cold And Hot Start Emissions, S. Sabate, March 1996 11 These changes to the heavy duty energy rates are described in the heavy duty vehicles emission rate report. All 

heavy duty vehicles uses the same energy rates, but are differentiated by drive cycle and weight. Therefore, the 

vehicle specific power (VSP) distribution of these vehicles differs. 

7 
1.3.3 Changes to Engine Technologies 

Engine technologies other than conventional internal combustion are not used 

substantially in the MOVES2010 default database. While these engine technologies each have 

different energy rates (Table 1-7), emission rates for pollutants other than energy are either set 

equivalent to the rate for conventional internal combustion vehicles or to zero.12,13 Therefore, 

“conventional internal combustion” in the MOVES2010 database is effectively a description of 

all engine types other than electric for non-energy emissions. In recognition of this convention, 

we removed all engine technologies other than conventional and electric from the MOVES2010a 

database. 

Table 1-7 – Engine Technologies in MOVES2010 

engTechID Engine Technology Name In MOVES2010a 

1 Conventional Internal Combustion YES 

2 Advanced Internal Combustion 

11 

Moderate Hybrid - Conventional Internal 

Combustion 

12 Full Hybrid - Conventional Internal Combustion 

20 Hybrid - Advanced Internal Combustion 

21 Moderate Hybrid - Advanced Internal Combustion 

22 Full Hybrid - Advanced Internal Combustion 

30 Electric YES 

40 Fuel Cell 

50 Hybrid - Fuel Cell 

As reflected in Table 1-7, the database tables were altered to reflect these changes. 

Additionally, the emission rates supporting these engine technologies (2.8 million rows) were 

removed from the 4 million row MOVES2010 emissionratebyage table. Approximately 8,600 

rows were removed from the emissionrate table. 

1.4 Updating Energy Rates 

After modifying the database structure and populating it with transformed energy rates, 

several additional changes were made. The 2008 and newer model year light duty vehicles 

(regulatory classes 20 and 30) were updated based on new data (model year 2008-2009) and 

rulemaking projections (model year 2010+). We also updated the energy emission rates to 

reflect the 2011 CAFE rulemaking and the 2012-2016 Light Duty Greenhouse Gas (LD GHG) 

and CAFE rulemakings. A number of other minor changes were also made.14,15 

12 As an example, advanced internal combustion engines have criteria emission rates equivalent to conventional 

internal combustion engines, but electric engines have criteria emission rates equaling zero.

13 In Draft MOVES2009 and MOVES2010, sourcetypeid 31 and 32 have non-zero penetrations of engtechid 2 in 

model years 2008 and newer. In earlier model versions, engine tech 2 was used as a means of reaching the fuel 

economy targets set in the 2008-2011 CAFE light truck rule. The changes described in this document negate the 

need for the penetration of advanced engine technology.

14 An error was corrected in light duty diesel energy starts. To fix the problem, start-emission rates for model year 

2000 and newer light and medium duty diesel vehicles (reg class 20, 30, 41, &42) were set to the MY 1999 rate. 

This is an approximately 55% reduction from the corresponding rates in the MOVES2010 database. While a large 

8 
The new energy consumption rates were based on a top-down analysis whereby CO2 

emission rates output from MOVES were calibrated to projected CO2 emission rates. CO2 

emissions were used due to their direct proportionality to energy consumption rates. We assume 

that the rulemakings affected the quantity of energy consumed, but not the distribution between 

operating modes, nor the ratio between start and running.16 As a result, we adjusted the energy 

rates using simple ratios between the old emission rates and the new emission rates (Table 1-8). 

Baseline values were derived by running MOVES2010 at the national/annual level using an 

input database that produced emission output only for regulatory classes 20 and 30. Emission 

quantity was divided by vehicle miles traveled to determine emission rates. 

Model year 2008 and model year 2009 data were drawn from EPA’s “Light-Duty 

Automotive Technology, Carbon Dioxide Emissions, and Fuel Economy Trends: 1975 through 

2009” (EPA420-R-09-014). The “Lab” average CO2 values for each model year were adjusted 

upward by 25% to reflect real world fuel consumption.17 The gasoline vehicles were set to this 

value. As the CAFE rules regulate fuel consumption in miles per gallon and treat gasoline and 

diesel vehicles equally, diesel energy consumption rates were multiplied by approximately 1.15 

in order to compensate for the greater energy density of diesel fuel. 18 

For model year 2011 through 2016, rates were derived from the model year 2012-2016 

Light Duty Greenhouse Gas (LD GHG) rulemaking analysis. The projections used in 

MOVES2010a are based upon the same assumptions as used the emission modeling conducted 

for the LD GHG rule. Model year 2010 was interpolated as a midpoint between model year 

2009 and 2011. Note that the regulatory standards for model year 2011 and newer are in a 

classification schema that differs from that used in MOVES2010a.19 Using vehicle level data 

from the rulemaking, we reanalyzed the vehicles to match the MOVES2010a vehicle 

classification scheme. As a result of this difference in classification scheme, the average CO2 

emission rate shown in this document is not expected to match those in the regulatory 

documents. 

fraction of this particular process, light duty diesel energy consumption is approximately 3% of total light and 

medium duty energy consumption, and start emissions are approximately 3% of light and medium duty diesel 

energy consumption. The impact of this change on total light and medium duty energy consumption is 

approximately 0.05%.

15 The 2008-2011 CAFE light truck rule was reflected in MOVES2010 through the use of advanced internal 

combustion vehicles. For MOVES2010a, we removed this engine technology and directly modified the energy rates 

for regclassid 30 to reflect the CAFE rules.

16 Maintaining the same ratio between running and start energy consumption rates likely overstates the reductions to 

the start process, and may be revisited in future MOVES model versions. While some technologies that reduce 

energy consumption (ie, engine downsizing) reduce start energy consumption, many others (such as aerodynamic 

improvements) do not. As starts are a very small portion of total energy consumption, the choice of approach has 

little impact.

17 Final Rulemaking: Light-Duty Vehicle Greenhouse Gas Emissions Standards and Corporate Average Fuel 

Economy Standards (published May 7, 2010). In miles per gallon, there is approximately a 25% gap between 

laboratory measured and real world achieved fuel economies.

18 The relative energy densities of diesel and gasoline fuel are approximately 129,000 btu/gallon and 115,000 

btu/gallon respectively.

19 In MYs 2011 and later, small SUVs are considered cars, rather than light trucks under the CAFE and GHG 

regulations. 

9 
Projected improvements in air conditioning system efficiency were included in the 

energy rates themselves rather than in a modification of the MOVES2010a air conditioning 

function. However, because the MOVES A/C adjustments are multiplicative, this change will 

also reduce the energy consumption from air conditioning. 

For the model year 2011 CAFE standards, a 1.15x adjustment was made for diesel 

vehicles. For 2012 and beyond, the diesel vehicles were presumed to meet the same CO2 

standard as the gasoline vehicles. 

Rates for model years after 2016 were set equivalent to model year 2016. The following 

tables (Table 1-9,Table 1-10,Table 1-11, & Table 1-12) show the g/mile rate for the laboratory 

combined Federal Test Procedure (FTP)/Highway Fuel Economy Test (HFET) driving schedules 

and on-road value equivalents. The tables showing on-road values are what were used to modify 

the model. Note that no source type is composed solely of regulatory class 30, and that these 

tables were produced using a set of user input files that isolate the output of this regulatory class. 

Table 1-8 – Ratios used to develop new rates in MOVES2010a20 

2008 

Ratios Used 

From MOVES2010 to MOVES2010a 

Trucks Cars 

Gas Diesel Gas Diesel 

0.904 0.723 0.981 1.007 

2009 0.896 0.716 0.969 0.995 

2010 0.898 0.717 0.985 1.011 

2011 0.831 0.663 1.002 1.028 

2012 0.790 0.550 0.919 0.823 

2013 0.769 0.535 0.893 0.800 

2014 0.747 0.519 0.868 0.777 

2015 0.716 0.497 0.830 0.743 

2016 0.677 0.470 0.782 0.700 

20 Note that these ratios were applied against the emissionrate table, and that the model year 2008-2011 light duty 

truck rule was reflected in MOVES2010 through an engine technology mix. Thus, the CO2 output from 

MOVES2010 was actually quite a bit lower than these ratios would indicate. 

10 
Table 1-9 – Test Cycle MPG 

2008 

MPG - Test Cycle 

MOVES2010 MOVES2010a 

Trucks Cars Trucks Cars 

Gas Diesel Gas Diesel Gas Diesel Gas Diesel 

20.5 16.4 29.7 26.7 22.7 22.7 30.5 30.5 

2009 20.5 16.4 29.7 26.7 22.9 22.9 30.9 30.9 

2010 20.6 16.4 29.8 26.7 22.9 22.9 30.4 30.4 

2011 20.6 16.4 29.8 26.8 24.8 24.8 29.9 29.9 

2012 20.7 16.5 29.9 26.8 26.1 29.9 32.7 37.4 

2013 20.7 16.5 29.9 26.8 26.9 30.8 33.7 38.5 

2014 20.7 16.5 30.0 26.8 27.7 31.7 34.7 39.7 

2015 20.7 16.5 30.0 26.9 29.0 33.2 36.3 41.5 

2016 20.8 16.5 30.0 26.9 30.7 35.1 38.5 44.1 

Table 1-10 – On-road MPG 

2008 

MPG - On Road 

MOVES2010 MOVES2010a 

Trucks Cars Trucks Cars 

Gas Diesel Gas Diesel Gas Diesel Gas Diesel 

16.4 13.1 23.8 21.3 18.1 18.1 24.4 24.4 

2009 16.4 13.1 23.8 21.4 18.3 18.3 24.7 24.7 

2010 16.5 13.1 23.8 21.4 18.3 18.3 24.3 24.3 

2011 16.5 13.1 23.9 21.4 19.9 19.8 24.0 24.0 

2012 16.5 13.2 23.9 21.4 20.9 23.9 26.2 30.0 

2013 16.5 13.2 23.9 21.5 21.5 24.6 26.9 30.8 

2014 16.6 13.2 24.0 21.5 22.2 25.4 27.7 31.8 

2015 16.6 13.2 24.0 21.5 23.2 26.5 29.0 33.2 

2016 16.6 13.2 24.0 21.5 24.5 28.1 30.8 35.3 

11 
Table 1-11 – Test-Cycle CO2 

2008 

CO2 - Test Cycle 

MOVES2010 MOVES2010a 

Trucks Cars Trucks Cars 

Gas Diesel Gas Diesel Gas Diesel Gas Diesel 

433.9 621.8 299.2 381.9 392.0 449.4 291.4 333.7 

2009 432.9 621.0 298.7 381.3 388.0 444.8 287.6 329.4 

2010 431.9 620.1 298.3 380.8 388.0 444.8 292.0 334.5 

2011 431.1 619.4 297.8 380.4 358.1 410.5 296.8 339.9 

2012 430.3 618.7 297.4 380.0 339.9 340.2 271.9 271.9 

2013 429.6 618.1 297.0 379.6 330.6 330.9 264.1 264.1 

2014 429.0 617.5 296.7 379.2 320.5 320.8 256.4 256.4 

2015 428.4 617.0 296.4 378.9 306.6 306.9 245.0 245.0 

2016 427.8 616.5 296.1 378.6 289.6 289.9 230.6 230.6 

Table 1-12 – On-road CO2 

2008 

CO2 - On Road 

MOVES2010 MOVES2010a 

Trucks Cars Trucks Cars 

Gas Diesel Gas Diesel Gas Diesel Gas Diesel 

542.3 777.3 374.1 477.3 490.0 561.7 364.2 417.2 

2009 541.1 776.2 373.4 476.7 485.0 556.0 359.5 411.8 

2010 539.9 775.2 372.8 476.1 485.0 556.0 365.0 418.1 

2011 538.9 774.2 372.3 475.5 447.6 513.1 370.9 424.9 

2012 537.9 773.4 371.7 475.0 424.9 425.3 339.8 339.8 

2013 537.0 772.6 371.3 474.5 413.2 413.6 330.1 330.1 

2014 536.2 771.9 370.8 474.0 400.6 401.0 320.5 320.5 

2015 535.5 771.2 370.4 473.6 383.2 383.6 306.3 306.3 

2016 534.8 770.6 370.1 473.2 362.0 362.3 288.2 288.2 

12 
Following the conventions in MOVES2010, for all years, electricity, E85 (85% 

ethanol/gasoline blends), and compressed natural gas (CNG) energy consumption rates were set 

equal to gasoline. Based on MOVES2010, CNG start energy rates were set equal to the gasoline 

rates for starts multiplied by 1.05 

1.5 Inventory Impacts of Changes relative to MOVES2010 

The structural changes described in this document had little impact on model results. For 

any pollutant, national annual scale runs conducted for calendar year 2001 with the new database 

differ by less than 0.1% as compared to MOVES2010. A few specific processes related to 

energy differ by greater amounts (<10%), but have insignificant impact on total inventories. 

With one exception, there are no changes in processes unrelated to energy.21 

The data changes, which reflect new data and the model year 2012-2016 LD GHG 

rulemaking, impact the results to a greater extent than the structural changes. As described 

above, we conducted national annual runs in order to estimate the impact of the database 

changes. The structural changes were evaluated with a national annual run in calendar year 

2001. Calendar year 2001 was chosen because it predates any of the new data in the database. A 

second run was conducted in calendar year 2021 to assess the impact of the new data and 

projections for model year 2008 and newer. The MOVES runs were conducted with all vehicle 

types and all fuel types. 

21 Ammonia (NH3) emissions also increase with the new database. The MOVES2010 database did not have NH3 

emission rates for engine technologies other than conventional internal combustion. Therefore the advanced internal 

combustion light trucks in MOVES2010 erroneously did not produce NH3 emissions. MOVES2010a fixes this 

issue. 

13 
Table 1-13 – Fuel/Pollutant/Process affected in Calendar Year 2001 

Fuel 

Affected 

Pollutant 

Affected 

Pollutant (Text) Processes 

Affected 

Process (Text) 

% Change 

CNG 90 CO2 2 Starts -8% 

CNG 91 Energy 2 Starts -8% 

CNG 93 Energy 2 Starts -8% 

Diesel 115 PM2.5 - Sulfate 2 Starts -4% 

Diesel 105 PM10 - Sulfate 2 Starts -4% 

Diesel 31 SO2 16 Crankcase - Starts -4% 

Diesel 90 CO2 2 Starts -4% 

Diesel 105 PM10 16 Crankcase - Starts -4% 

Diesel 115 PM2.5 16 Crankcase - Starts -4% 

Diesel 91 Energy 2 Starts -4% 

Diesel 92 Energy 2 Starts -4% 

Diesel 93 Energy 2 Starts -4% 

Diesel 31 SO2 2 Starts -4% 

Diesel 98 CO2 2 Starts -4% 

CNG 98 CO2 2 Starts -2% 

Gasoline 105 PM10- Sulfate 16 Crankcase - Starts -1% 

Gasoline 115 PM2.5- Sulfate 16 Crankcase - Starts -1% 

Gasoline 115 PM2.5- Sulfate 2 Starts -1% 

Gasoline 105 PM10- Sulfate 2 Starts -1% 

Gasoline 92 CO2 2 Starts -1% 

Gasoline 31 SO2 2 Starts -1% 

Gasoline 90 Energy 2 Starts -1% 

Gasoline 93 Energy 2 Starts -1% 

Gasoline 91 Energy 2 Starts -1% 

Gasoline 31 SO2 16 Crankcase - Starts -1% 

The calendar year 2001 results shown in Table 1-13 are driven by the modification of the 

energy rate sourcebins from a size/weight basis to a regulatory class basis. These effects are 

minimal on most pollutants and processes. Specifically, the organizational changes to the 

database had no effect on heavy duty running rates, which had already been aggregated in this 

manner. It also had minimal effect on those source types (passenger cars and motorcycles), 

which have a 1:1 to relationship with regulatory class. All the processes listed above are related 

to starts, which have a relatively small impact on total energy consumption. 

Passenger truck and light commercial trucks are the only source types that were 

composed of similar regulatory classes in MOVES 2010 but different size/weight distributions. 

As a result, post-aggregation, the revised energy rates for each of these vehicles converged into a 

population weighted average of the two sets of energy rates. In regulatory class 30, the diesel 

fuel type is dominated by light commercial trucks, while the gasoline fuel type is dominated by 

passenger trucks. For further detail, a narrower light truck inventory comparison between 

MOVES2010 and MOVES2010a is shown below for calendar year 2007 (Table 1-14): 

14 
Table 1-14 – Comparison of National CO2 Inventories in Calendar Year 2007 (Million Metric Tons) 

MOVES2010 MOVES2010a Difference Percentage 

Gasoline Passenger Truck 400.6 415.0 3.6% 

Gasoline Light Commercial Truck 132.2 122.7 -7.2% 

Diesel Passenger Truck 10.2 9.8 -4.7% 

Diesel Light Commercial Truck 22.6 23.0 1.9% 

Total 565.6 570.4 0.9% 

In the second MOVES test run (calendar year 2021), we evaluated the impact of the 

energy rate updates (Table 1-15). As the scope of the impacts is larger, the table below is 

aggregated by emission process in order to show impacts by fuel and pollutant. Decreases are 

seen in energy related pollutants such as PM sulfate, energy and CO2, SO2. Smaller reductions 

are seen in ethanol emissions, as well as those emissions related to refueling and spillage. 

Table 1-15 – Impacts of Changes in Calendar Year 2021 

Fuel Affected 

Pollutant 

Affected 

Pollutant (Text) % 

Change 

Gasoline 115 PM2.5 - Sulfate -14% 

Gasoline 105 PM10 - Sulfate -14% 

Gasoline 92 Energy -14% 

Gasoline 91 Energy -14% 

Gasoline 93 Energy -14% 

Gasoline 90 CO2 -14% 

Gasoline 31 SO2 -14% 

Gasoline 98 CO2 -14% 

Gasoline 21 Ethanol -5% 

Gasoline 87 VOC -2% 

Gasoline 80 NMOG -2% 

Gasoline 79 NMHC -2% 

Gasoline 86 TOG -2% 

Gasoline 1 THC -2% 

Diesel 92 Energy -1% 

Diesel 93 Energy -1% 

Diesel 91 Energy -1% 

Diesel 90 CO2 -1% 

Diesel 98 CO2 -1% 

Diesel 105 PM10 -1% 

Diesel 115 PM2.5 -1% 

Diesel 31 SO2 -1% 

Gasoline 5 Methane 1% 

Diesel 30 NH322 7% 

Gasoline 30 NH3 25% 

22 As noted in 21 above, this increase in ammonia emissions is due to a related fix. 

15 
2 Methane and N2O in MOVES2010 

In MOVES2004, EPA based its estimates of emissions of methane (CH4) and nitrous 

oxide (N2O) on test results of the Federal Test Procedure (FTP) and the then current 

version of EPA's "Inventory of U.S. Greenhouse Gas Emissions and Sinks." For Draft 

MOVES2009, EPA used both an enlarged database of test results plus a newer version of 

EPA's "Sources and Sinks" report23 (primarily Table A-88 of its Annex 3). 

EPA used the estimates from its "Sources and Sinks" report to fill holes its test data 

(i.e., when either no or limited results from Federal Test Procedure (FTP) were 

available). 

Emission rates for N2O and for CH4 in Draft MOVES2009 were estimated for engine 

starts and for running operation and were not calculated for individual operating modes. 

This is in contrast to rates for other pollutants (e.g., HC, CO, NOX) for which running 

emissions are calculated for each of 23 operating modes (based on vehicle speed and 

power) and for which start emissions are calculated for each of 8 operating modes (based 

on vehicle soak time prior to engine start). 

Differences Between MOVES and "Sources and Sinks" 

EPA publishes an annual report of emissions of greenhouse gases ("Inventory of U.S. 

Greenhouse Gas Emissions and Sinks"). Although the basic emission rates in EPA's 

"Sources and Sinks" report are based on technology groups, the basic emission rates in 

MOVES are based on (among other parameters) model year groups. Therefore , the 

initial analysis was to estimate emission rates by technology groups and then to convert 

those to model year groups. The conversion from technology groups to individual model 

years was based on the distribution of the individual technologies in each model year as 

detailed in the "Sources and Sinks" report (Tables A-84 through A-87 of the 2008 

publication). 

A second difference between those sets of rates is that the rates in EPA's "Sources and 

Sinks" report are estimates of emissions over the entire FTP driving cycle (in grams per 

mile) including the engine start while those in MOVES are given separately for starts 

(grams per start) and running operation (grams per hour). 

To estimate running emission rates of N2O and CH4 in the draft MOVES2009 model, 

EPA used the same approach that it used in the analysis for the MOVES2004 model. 

That is, EPA assumed that the hourly emissions rate for the Bag-2 portion of the FTP is 

representative of the overall running rate (in grams per hour). To calculate this rate, EPA 

multiplied the Bag-2 emissions (in grams per mile) by the average speed of Bag-2 (i.e., 

16.023 miles per hour), which produces the requisite emission rate (in units of grams per 

hour). 

23 "Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 – 2006," EPA Report No. EPA 430-R-08-005, 

April 2008. Available at: http://www.epa.gov/climatechange/emissions/usinventoryreport.html 

16 
Multiplying that hourly rate by the duration of the full LA-4 driving cycle (i.e., 1,372 

seconds or 0.381111 hours) yields the total estimated running emissions of the LA-4 (or 

FTP) in grams. Then, multiplying the composite FTP emissions (in grams per mile) by 

the length of the LA-4 driving cycle (7.45 miles) yields the estimated total emissions (in 

grams) produced during the FTP. Subtracting those two quantities (total grams emitted 

during the FTP minus the total grams from the running emissions) yields an estimate of 

the emissions (in grams) from a generic start (57 percent hot-start and 43 percent coldstart). 

It is these two rates (running emissions in grams per hour and generic start emissions 

in grams per start) that EPA used in the MOVES2004 model and updated in the Draft 

MOVES2009 model. 

17 
2.1 Nitrous Oxide Emission Rates: 

Table 3-1 compares the nitrous oxide FTP emission rates (by technology group) from 

EPA's "Sources and Sinks" report, the comparable rates from MOVES2004, and the 

means of test data obtained from a study by Environment Canada.24 

Table 2-1: Comparison of FTP Nitrous Oxide Emissions (grams / mile) 

Vehicle Type / 

Control Technology 

Gasoline Passenger Cars 

EPA Tier 2 

LEVs 

"Sources & 

Sinks" Rpt 

0.0036 

0.0150 

MOVES2004 

0.012 

0.012 

FTP Data 

0.0050 

0.0101 

EPA Tier 1 

EPA Tier 0 

0.0429 

0.0647 

0.030 

0.054 

0.0283 

0.0538 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.0504 

0.0197 

0.0197 

0.042 

0.017 

0.017 

--­

--­

--­

Gasoline Light-Duty Trucks 

EPA Tier 2 

LEVs 

0.0066 

0.0157 

0.009 

0.009 

--­

0.0148 

EPA Tier 1 

EPA Tier 0 

0.0871 

0.1056 

0.067 

0.090 

0.0674 

0.0370 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.0639 

0.0218 

0.0220 

0.054 

0.019 

0.019 

0.0906 

--­

--­

Gasoline Heavy-Duty Vehicles 

EPA Tier 2 

LEVs 

0.0134 

0.0320 

0.019 

0.019 

--­

--­

EPA Tier 1 

EPA Tier 0 

0.1750 

0.2135 

0.138 

0.183 

--­

0.0814 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.1317 

0.0473 

0.0497 

0.113 

0.041 

0.043 

--­

--­

--­

24 "Greenhouse Gas Emissions from 1997-2005 Model Year Light Duty Vehicles," Environment Canada Report No. 

ERMD Report #04-44. 

18 
Comparison of FTP Nitrous Oxide Emissions (grams / mile) Con't 

Vehicle Type / "Sources & 

Control Technology Sinks" Rpt MOVES2004 FTP Data 

Diesel Passenger Cars 

Advanced 0.0010 0.001 --­

Moderate 0.0010 0.001 --­

Uncontrolled 0.0012 0.001 --­

Diesel Light-Duty Trucks 

Advanced 0.0015 0.002 --­

Moderate 0.0014 0.002 --­

Uncontrolled 0.0017 0.002 --­

Diesel Heavy-Duty Vehicles 

Advanced 0.0048 0.005 0.0049 

Moderate 0.0048 0.005 --­

Uncontrolled 0.0048 0.005 --­

Motorcycles 

Non-Catalyst Control 

Uncontrolled 

0.0069 

0.0087 

0.007 

0.009 

--­

--­

Twenty-two of the thirty-two technology groups contain no FTP N2O test data. For those 

rates, we use the "Sources and Sinks" data. 

19 
In the following table, we take those 32 composite FTP N2O rates (22 based on the "Sources 

and Sinks" rates and the remaining 10 based on newer FTP test data) and disaggregate them into 

running rates (in grams per hour) and start rates (in grams per generic start). 

Table 2-2: Separating Composite FTP N2O Emissions into Running and Start 

Vehicle Type / 

Control Technology 

Gasoline Passenger Cars 

EPA Tier 2 

LEVs 

FTP Comp 

(g / mile) 

0.0050 

0.0101 

Running 

(g / hour) 

0.0399 

0.0148 

Start 

(g / start) 

0.0221 

0.0697 

EPA Tier 1 

EPA Tier 0 

0.0283 

0.0538 

0.2316 

0.6650 

0.1228 

0.1470 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.0504 

0.0197 

0.0197 

0.6235 

0.2437 

0.2437 

0.1379 

0.0539 

0.0539 

Gasoline Light-Duty Trucks 

EPA Tier 2 

LEVs 

0.0066 

0.0148 

0.0436 

0.0975 

0.0325 

0.0728 

EPA Tier 1 

EPA Tier 0 

0.0674 

0.0370 

0.6500 

0.2323 

0.2546 

0.1869 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.0906 

0.0218 

0.0220 

0.8492 

0.2044 

0.2062 

0.3513 

0.0845 

0.0853 

Gasoline Heavy-Duty Vehicles 

EPA Tier 2 

LEVs 

0.0134 

0.0320 

0.1345 

0.3213 

0.0486 

0.1160 

EPA Tier 1 

EPA Tier 0 

0.1750 

0.0814 

1.7569 

0.8172 

0.6342 

0.2950 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.1317 

0.0473 

0.0497 

1.3222 

0.4749 

0.4990 

0.4773 

0.1714 

0.1801 

20 
Separating Composite FTP N2O Emissions into Running and Start Con't 

Vehicle Type / FTP Comp Running Start 

Control Technology (g / mile) (g / hour) (g / start) 

Diesel Passenger Cars 

Advanced 0.0010 0.0168 0.0010 

Moderate 0.0010 0.0168 0.0010 

Uncontrolled 0.0012 0.0202 0.0012 

Diesel Light-Duty Trucks 

Advanced 0.0015 0.0253 0.0015 

Moderate 0.0014 0.0236 0.0014 

Uncontrolled 0.0017 0.0286 0.0018 

Diesel Heavy-Duty Vehicles 

Advanced 0.0049 0.0828 0.0051 

Moderate 0.0048 0.0809 0.0049 

Uncontrolled 0.0048 0.0809 0.0049 

Motorcycles 

Non-Catalyst Control 

Uncontrolled 

0.0069 

0.0087 

0.0854 

0.1076 

0.0189 

0.0238 

21 
2.2 Methane Emission Rates: 

The following table (table 3-3) compares the methane FTP emission rates (by technology 

groups) from the EPA's "Sources and Sinks" report, the rates from MOVES2004, and the means 

of the Environment Canada test data. 

Table 2-3: Comparison of FTP Methane Emissions (grams / mile) 

Vehicle Type / 

Control Technology 

Gasoline Passenger Cars 

EPA Tier 2 

LEVs 

"Sources & 

Sinks" Rpt 

0.0173 

0.0105 

MOVES2004 

0.013 

0.013 

FTP Data 

0.0110 

0.0083 

EPA Tier 1 

EPA Tier 0 

0.0271 

0.0704 

0.020 

0.066 

0.0242 

0.0665 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.1355 

0.1696 

0.1780 

0.133 

0.162 

0.171 

0.1351 

0.1568 

--­

Gasoline Light-Duty Trucks 

EPA Tier 2 

LEVs 

0.0163 

0.0148 

0.017 

0.017 

--­

0.0117 

EPA Tier 1 

EPA Tier 0 

0.0452 

0.0776 

0.034 

0.071 

0.0357 

0.0708 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.1516 

0.1908 

0.2024 

0.143 

0.184 

0.195 

0.1413 

0.0390* 

--­

Gasoline Heavy-Duty Vehicles 

EPA Tier 2 

LEVs 

0.0333 

0.0303 

0.034 

0.034 

--­

--­

EPA Tier 1 

EPA Tier 0 

0.0655 

0.2630 

0.047 

0.218 

0.0515 

0.2487 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.2356 

0.4181 

0.4604 

0.208 

0.403 

0.445 

0.2135 

--­

--­

* Possible outlier (single test vehicle). 

22 
Comparison of FTP Methane Emissions (grams / mile) Con't 

Vehicle Type / "Sources & 

Control Technology Sinks" Rpt MOVES2004 FTP Data 

Diesel Passenger Cars 

Advanced 0.0005 0.001 --­

Moderate 0.0005 0.001 --­

Uncontrolled 0.0006 0.001 --­

Diesel Light-Duty Trucks 

Advanced 0.0010 0.001 --­

Moderate 0.0009 0.001 --­

Uncontrolled 0.0011 0.002 --­

Diesel Heavy-Duty Vehicles 

Advanced 0.0051 0.004 0.0039 

Moderate 0.0051 0.004 --­

Uncontrolled 0.0051 0.004 --­

Motorcycles 

Non-Catalyst Control 

Uncontrolled 

0.0672 

0.0899 

0.067 

0.090 

--­

--­

Note that 17 of the 32 technology groups have no FTP CH4 test data. For those rates, the 

"Sources and Sinks" data for the FTP rates were used. Also, for non-catalyst light-duty gasoline 

trucks, there was only one FTP result, and that single FTP methane result appears to be an outlier 

(i.e., too low). Therefore, for that technology group we also used the "Sources and Sinks" rate. 

In the following table (Table 3-4), those 32 composite FTP CH4 rates (18 based on the 

"Sources and Sinks" rates and the remaining 14 based on newer FTP test data) were 

disaggregated into running rates (in grams per hour) and start rates (in grams per generic start). 

23 
Table 2-4: Separating Composite FTP CH4 Emissions into Running and Start 

Vehicle Type / 

Control Technology 

Gasoline Passenger Cars 

EPA Tier 2 

LEVs 

FTP Comp 

(g / mile) 

0.0110 

0.0083 

Running 

(g / hour) 

0.1131 

0.0632 

Start 

(g / start) 

0.0386 

0.0379 

EPA Tier 1 

EPA Tier 0 

0.0242 

0.0665 

0.3164 

0.9952 

0.0596 

0.1165 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.1351 

0.1568 

0.1780 

2.1613 

2.3654 

2.6855 

0.1831 

0.2666 

0.3026 

Gasoline Light-Duty Trucks 

EPA Tier 2 

LEVs 

0.0163 

0.0117 

0.1114 

0.0801 

0.0790 

0.0568 

EPA Tier 1 

EPA Tier 0 

0.0357 

0.0708 

0.3775 

0.9788 

0.1223 

0.1544 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.1413 

0.1908 

0.2024 

2.0255 

0.4807 

2.4970 

0.2808 

0.1071 

0.5563 

Gasoline Heavy-Duty Vehicles 

EPA Tier 2 

LEVs 

0.0333 

0.0303 

0.3111 

0.2831 

0.1295 

0.1179 

EPA Tier 1 

EPA Tier 0 

0.0515 

0.2487 

0.4816 

3.6353 

0.2005 

0.4674 

Oxidation Catalyst 

Non-Catalyst Control 

Uncontrolled 

0.2135 

0.4181 

0.4604 

2.8555 

5.5908 

6.1565 

0.5026 

0.9841 

1.0837 

24 
Separating Composite FTP CH4 Emissions into Running and Start Con't 

Vehicle Type / FTP Comp Running Start 

Control Technology (g / mile) (g / hour) (g / start) 

Diesel Passenger Cars 

Advanced 0.0005 0.0098 0.0000 

Moderate 0.0005 0.0098 0.0000 

Uncontrolled 0.0006 0.0117 0.0000 

Diesel Light-Duty Trucks 

Advanced 0.0010 0.0195 0.0000 

Moderate 0.0009 0.0176 0.0000 

Uncontrolled 0.0011 0.0215 0.0000 

Diesel Heavy-Duty Vehicles 

Advanced 0.0039 0.0765 0.0000 

Moderate 0.0051 0.0997 0.0000 

Uncontrolled 0.0051 0.0997 0.0000 

Motorcycles 

Non-Catalyst Control 

Uncontrolled 

0.0672 

0.0899 

1.0138 

1.3563 

0.1143 

0.1528 

25 
2.3 Alternative Fuels 

Since no additional FTP data were available, the emission rates of N2O and CH4 in the draft 

MOVES2009 model are based entirely on EPA's "Inventory of U.S. Greenhouse Gas Emissions 

and Sinks: 1990 - 2006" (Table A-89 of its Annex 3). Those FTP rates from that report are 

reproduced in the following table (Table 3-5): 

Table 2-5 Composite FTP Emissions from Alternative Fuels 

Vehicle Type / N2O CH4 

Fuel Type (g / mile) (g / mile) 

Light-Duty Vehicles 

Methanol 0.067 0.018 

CNG 0.050 0.737 

LPG 0.067 0.037 

Ethanol 0.067 0.055 

Biodiesel (BD20) 0.001 0.000 

Heavy-Duty Vehicles 

Methanol 0.175 0.066 

CNG 0.175 1.966 

LNG 0.175 1.966 

LPG 0.175 0.066 

Ethanol 0.175 0.197 

Buses 

Methanol 0.175 0.066 

CNG 0.175 1.966 

Ethanol 0.175 0.197 

26 
Disaggregating those composite FTP rates into start and running rates yields the following 

results: 

Table 2-6: Methane Emission Rates from Alternative Fuels 

Vehicle Type / 

Fuel Type 

Light-Duty Vehicles 

Methanol 

CNG 

LPG 

Ethanol 

Running 

(g / hour) 

0.2192 

8.9755 

0.4506 

0.6698 

Starts 

(g / start) 

0.0506 

2.0700 

0.1039 

0.1545 

Heavy-Duty Vehicles & Buses 

Methanol 

CNG 

LNG 

LPG 

Ethanol 

0.8038 

23.9429 

23.9429 

0.8038 

2.3992 

0.1854 

5.5218 

5.5218 

0.1854 

0.5533 

Table 2-7: Nitrous Oxide Emission Rates from Alternative Fuels 

Vehicle Type / 

Fuel Type 

Light-Duty Vehicles 

Methanol 

CNG 

LPG 

Ethanol 

Running 

(g / hour) 

0.6431 

0.4799 

0.6431 

0.6431 

Starts 

(g / start) 

0.2541 

0.1896 

0.2541 

0.2541 

Heavy-Duty Vehicles & Buses 

Methanol 

CNG 

LNG 

LPG 

Ethanol 

1.6797 

1.6797 

1.6797 

1.6797 

1.6797 

0.6636 

0.6636 

0.6636 

0.6636 

0.6636 

27 
3 Updates to the Methane Rates for MOVES 2010a 

For MOVES2010a, the MOVES calculations to derive methane (CH4 ) from total 

hydrocarbons (THC) values were updated, rather than as a separate emission rate as in earlier 

versions of the model. This change more closely aligns the methane calculations with the 

calculation of other hydrocarbon compounds in MOVES. As an example, volatile organic 

compounds (VOCs) are calculated in a chained (multiplicative) manner rather than as 

independent emission rate. Similarly, the chained calculation of methane is based upon the 

assumption of a direct relationship between CH4 and THC by age, vehicle type, and fuel. As 

seen earlier in this report, those vehicles that tend to have higher THC (such as heavy duty 

vehicles) also tend to have higher methane emissions. 

In the MOVES calculations, methane must be removed from the THC inventory in order 

to calculate values for other hydrocarbon species needed in air quality analysis. However, as the 

standalone methane emission rates were neither age nor temperature sensitive, there were some 

disconnects between THC and methane (where THC varied with age and temperature, but 

methane did not). “Chaining” the calculation of methane emissions to THC values allows EPA 

to make these improvements to the methane inventory, as well. 

Additionally, connecting THC and methane removes a potential issue where methane 

emissions could have exceeded THC emissions. Where THC and CH4 are both calculated 

independently in MOVES2010 and earlier MOVES versions, MOVES could calculate a negative 

amount for these other compounds, which is physically not possible. 

In MOVES2010a, CH4 is calculated by applying a multiplicative factor (CH4THCRAtio 

in the MethaneTHCRatio table) to the calculated THC value after all adjustments to THC have 

been made for all fuel types. Once the CH4 value has been determined, CH4 is used in MOVES 

as it was before in all further calculations. 

To create the new rates for pre-model year 2003 vehicles, methane and THC Emission 

rates for all gasoline and diesel vehicles were read from the movesoutput file and the ratio is 

computed. Light duty vehicle, light duty truck, and heavy duty gasoline vehicles were the only 

source types which were run. All of the other source types were filled with these data. 

Motorcycles were filled with light duty vehicle rates. 

To create the new ratios for 2004 and newer vehicles, the MOVES 2010a rates were 

transferred from the MOVES2010 data using a process similar to that described above. The 

LDV rates are again used for the motorcycles. 

The methane ratios for 2007 and newer model year diesel trucks were not taken from the 

MOVES2010 estimates. The constant value of 0.5846 was derived from new technology diesel 

vehicle emission testing done for the Health Effects Institute (HEI) Advanced Collaborative 

Emissions Study (ACES)25 . 

25 HEI ACES: Khalek, I., Bougher, T., and Merritt, P. M. 2009. Phase 1 of the Advanced Collaborative Emissions 

Study. Prepared by Southwest Research Institute for the Coordinating Research Council and the Health Effects 

Institute, June 2009. Available at www.crcao.org. 

28 
Methane ratios for ethanol are a constant value of 0.37 for the running and engine start 

processes and zero for all other processes. All raw gasoline evaporative methane ratios can be 

assumed to be zero since gasoline formulations typically contains negligible amounts of 

methane. 

29