MOBILE6 Technical Documentation Index

This web page is a listing of the technical reports that provide the basis of the calculations in the MOBILE6 highway vehicle emission model.

For further MOBILE Model information on this web page, contact: fax (734-214-4939) or email:

NOTE: You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.

Report Title Mini-Synopsis
Report (PDF) (34 pp, 155 K, EPA420-R-01-054, November 2001)
Air Conditioning Activity Effects in MOBILE6 This report describes how calculations of air conditioning correction factors will account for variations in temperature, humidity, solar load, air conditioning malfunction rates and the fraction of vehicles with air conditioning.
Report (PDF) (105 pp, 1.85 MB, EPA420-R-01-055, November 2001)
Air Conditioning Correction Factors in MOBILE6 Describes new air conditioning exhaust emission correction factors based on tests of 38 vehicles at two locations. These factors predict emissions during full loading of the air conditioning system.
Report (PDF) (95 pp, 470 K, EPA420-R-01-018, April 2001)
Data (XLS) (592 K)
Evaluating Resting Loss and Diurnal Evaporative Emissions Using RTD Tests This report describes the analysis of data from real-time diurnal (RTD) tests on 270 vehicles.
Report (PDF) (103 pp, 466 K, EPA420-R-01-019, April 2001)
(see data for M6.EVP.001)
Modeling Hourly Diurnal and Interrupted Diurnal Emissions Based on Real-time Diurnal Data This report describes analysis of the hourly allocation of diurnal and resting loss emissions, including emissions from diurnals that begin in late morning ("interrupted diurnals").
Report (PDF) (36 pp, 116 K, EPA420-R-01-020, April 2001)
(see data for M6.EVP.001)
Evaluating Multiple Day Diurnal Evaporative Emissions Using RTD Tests This report presents an analysis of diurnal evaporative emissions from LDVs and LDTs occurring over periods of more than one day.
Report (PDF) (240K, EPA420-R-01-026, April 2001)
Spreadsheet (XLS) (403 K)
Update of Hot Soak Emissions Analysis This report incorporates the results of two studies to develop "hot soak" evaporative emission estimates at low fuel RVP.
Report (PDF) (59 pp, 243 K, EPA420-R-01-021, April 2001)
(see data for M6.EVP.001)
Modeling Diurnal and Resting Loss Emissions from Vehicles Certified to the Enhanced Evaporative Standards This document reports on EPA's methods of estimating the resting loss and diurnal evaporative hydrocarbon emissions from vehicles certified to the enhanced evaporative standards (i.e., some 1996 through 1998 and all 1999 and newer vehicles).
Report (PDF) (57 pp, 314 K, EPA420-R-01-022, April 2001)
Estimating Weighting Factors for Evaporative Emissions in MOBILE6 This document describes EPA plans to compute model-year and age specific average resting loss and diurnal emissions by weighting together the emissions of passing and failing vehicles according to their frequency in the in-use fleet.

Report (PDF) (65K, EPA420-R-01-030, April 2001)

Hot Soak Emissions as a Function of Soak Time This document describes the rate of decline in hot soak emissions over a one hour time period. This information will be used in MOBILE6 with the hot soak emissions and activity information from the two documents M6.FLT.004 and M6.EVP.004.
Report (PDF) (16 pp, 79 K, EPA420-R-01-023, April 2001)
Estimating Running Loss Evaporative Emissions in MOBILE6 This report examines the effects of "gross liquid leakers" (see report M6.EVP.009), and then compares recent running loss test results with the result of combining the estimated emissions of those leaking vehicles with the MOBILE5 running loss estimates.
Report (PDF) (210K, EPA420-R-01-024, April 2001)
Evaporative Emissions of Gross Liquid Leakers in MOBILE6 This document describes EPA's estimates of both the frequency of occurrence vehicles with significant leaks of liquid gasoline and the magnitude of the emissions from those leaks.
Report (PDF) (1.1MB, EPA420-R-02-002, January 2002)
Database (DBF) (1.9MB)
(same data as M6.STE.003)
Determination of Running Emissions as a Function of Mileage for 1981-1993 Model Year LDV and LDT This report is one of four describing in-use deterioration for 1981-93 model year cars and trucks.
M6.EXH.002 Report (PDF) (17 pp, 50K, EPA420-R-02-003, January 2002) Analysis of Emissions Deterioration Using Ohio and Wisconsin IM240 Data Describes analysis of running emissions using IM240 data. This analysis was used to determine high-emitter correction factors.
Report (PDF) (70K, EPA420-R-01-027, April 2001)

- data description (WPD) (10K)
- car/truck data (DBF) (7.2MB)
- diesel calcs (XLS) (90K)
- motorcycle data (XLS) (45K)
- more motorcycle data (XLS) (35K)
- motorcycle calcs (XLS) (60K)
- gasoline vehicle calcs (XLS) (275K)
- calc of start fractions (XLS) (16K)

Basic Exhaust Emission Rates of Open Loop Vehicles for MOBILE6 "Open loop" refers to vehicles which do not use electronic feedback systems to control the delivery of fuel to the engine cylinders. Motorcycles, older light-duty vehicles and most diesel vehicles are open-loop.
Report (PDF) (9 pp, 27 K, EPA420-R-01-031, April 2001)
Determination of Methane Offsets as a Function of Mileage for Light-Duty Cars and Trucks This document describes a methane "offset" to separate total hydrocarbons from non-methane hydrocarbons in MOBILE6 calculations and output. The report treats start and running emissions differently and models an offset that changes with vehicle deterioration.
Report (PDF) (67 pp, 314 K, EPA420-R-01-056, November 2001)
Determination of NOx and HC Basic Emission Rates, OBD and I/M Effects for Tier 1 and Later LDVs and LDTs This report describes proposed NOx and HC basic emission rates, OBD and I/M Effects for Tier 1, TLEV, LEV and ULEV Light Duty Vehicles and Trucks.
Report (PDF) (6 pp, 33 K, EPA420-R-01-041, July 2001)
MOBILE6 Estimates of Exhaust Emissions for 1994-and-later Light Duty Diesel Cars and Trucks This report summarizes how MOBILE6 will estimate start and running exhaust emissions for 1994-and-later light duty diesel cars and trucks.
Report (PDF) (35 pp, 87 K, EPA420-R-03-011, September 2003)
Update to the Determination of CO Basic Emission Rates, OBD and I/M Effects for Tier 1 and Later LDVs and LDTs This document (September 2003) updates and supercedes the CO emission factors originally described in the document M6.EXH.009 (April 2001). The update accounts for the changes made in MOBILE6.2 to account for the effects of Low Emitting Vehicle (LEV) and Tier 2 HC and NOx standards on CO emissions.
Report (PDF) (21 pp, 240 K, EPA420-R-03-012, September 2003)
Update to the Accounting for the Tier 2 and Heavy-Duty 2005/2007 Requirements in MOBILE6 This document (September 2003) updates and supercedes the CO emission factors originally described in the document M6.EXH.004 (November 2001) for light duty Tier 2 vehicles. The update accounts for the changes made in MOBILE6.2 to account for the effects of Tier 2 HC and NOx standards on CO emission rates.
Report (PDF) (15 pp, 171 K, EPA420-R-01-011, April 2001)
Soak Length Activity Factors for Start Emissions Describes the methodology used to estimate soak length activity factors for start emissions and lists the hourly activity factors that MOBILE6 will use.
Report (PDF) (38K, EPA420-R-01-012, April 2001)
Activity Data (PDF) (209 pp, 1.4 MB)
Soak Length Activity Factors for Hot Soak Emissions Describes the methodology used to estimate soak length activity factors for hot soak emissions and lists the hourly activity factors that MOBILE6 will use.
Report (PDF) (18 pp, 43 K, EPA420-R-01-013, April 2001)
Trip Length Activity Factors for Running Loss and Exhaust Running Emissions Describes the methodology used to estimate trip length activity factors for (evaporative) running loss and exhaust running emissions and lists the hourly activity factors that MOBILE6 will use.
Report (PDF) (17 pp, 78 K, EPA420-R-01-014, April 2001)
Data (XLS) (88K)
Calculations (XLS) (460K)
Soak length Activity Factors for Diurnal Emissions This report describes the method used to estimate soak length activity factors for diurnal emissions and lists the hourly activity factors proposed for MOBILE6.
Report (PDF) (59 pp, 1.86 MB, EPA420-R-01-047, September 2001)
Fleet Characterization Data for MOBILE6: Development and Use of Age Distributions, Average Mileage Accumulation Rates and Projected Vehicle Counts for Use in MOBILE6. This report describes the approach used to convert the information provided in M6.FLT.002 (PDF) (70 pp, 639 K, EPA420-P-98-016, June 1998)into registration distributions, mileage accumulation rates and projected vehicle counts for use in MOBILE6.
(a) Addendum & Clarifications (PDF) (14 pp, 45 K, EPA420-R-02-007, February 2002)
(b) Original M6.FLT.008
Full Report (PDF) (61 pp, 196 K, June 8, 1998)
Emission Control Technology Distributions Used in MOBILE6
(a) Clarification of inputs used in MOBILE6
(b) Original Report
Provides review of historical and future technologies and suggests appropriate groupings for emission factor analysis.
Report (PDF) (38 pp, 197 K, EPA420-R-01-039, July 2001)
Fuel Sulfur Effects on Exhaust Emissions: Recommendations for MOBILE6 This report describes EPA's estimates of the empirical relationship between fuel sulfur content and HC, NMHC, CO and NOx emissions as a function of vehicle technology and vehicle emissions for gasoline powered vehicles.
Report (PDF) (48 pp, 779K, EPA420-R-01-040, July 2001)
Fuel Oxygen Effects on Exhaust CO Emissions: Recommendations for MOBILE6 Describes analysis of data on effects of fuel oxygenates on CO emissions. Estimates percent benefits. Includes contractor report on older vehicles and EPA analysis of newer cars. Benefits will decrease as fleet shifts to new cars.
Report (PDF) (14 pp, 108 K, EPA420-R-01-033, April 2001)
Modeling Emission Factors for Compressed Natural Gas Vehicles This document examines the emissions benefits of CNGVs and how these benefits will be modeled in MOBILE6. It also describes the data the methodology used to determine these benefits.
Report (PDF) (7 pp, 41 K, EPA420-R-01-028, April 2001)
Estimating Emission Effects of RFG Gasoline in MOBILE6 This report describes the approach to estimate emissions benefits of reformulated gasoline.
Abstract and Report (PDF) (42 pp, 282 K, EPA420-P-02-005, August 2002)
Updating Fuel Economy Estimates in MOBILE6.3 (Draft) In this report, EPA proposes to update fuel economy estimates of previous MOBILE models. These updates will then be used to predict CO2 emissions.
Report (PDF) (28 pp, 171 K, EPA420-R-02-018, July 2002)
Update of Heavy-duty Emission Levels (Model Years 1988-2004) for Use in MOBILE6 This report describes the emission factors to be used for gasoline and diesel heavy duty vehicles in MOBILE6 and their derivation from available emission data.
Report (PDF) (48 pp, 294 K, EPA420-R-02-006, February 2002)
Update Heavy Duty Engine Emission Conversion Factors for MOBILE6: Analysis of Fuel Economy, Non-Engine Fuel Economy Improvements and Fuel Densities. This report describes the analysis of fuel economy for heavy-duty engines (1987-1996), and fuel density for gasoline and diesel. And it examines the use of non-engine fuel economy improvement devices for forecasting conversion factors in the future.
Report (PDF) (26 pp, 109 K, EPA420-R-02-004, January 2002)
Data Parameter Summary (XLS) (70K)
Raw Data & Figures (XLS) (110K)
Development and Use of Heavy Duty Defeat Device Emission Effects for MOBILE5 and MOBILE6 This report describes NOx emissions from HD diesel vehicles with "defeat devices" and after defeat device mitigation measures have been implemented.
Report (PDF) (22 pp, 117 K, EPA420-R-02-005, January 2002)
Update Heavy Duty Engine Emission Conversion Factors for MOBILE6: Analysis of BSFCs and Calculation of Heavy-duty Engine Emission Conversion Factors This report discusses the calculation of average engine brake-specific fuel consumption (BSFC) for model years 1987-1996, calculates conversion factors for all heavy-duty vehicle weight classes, and projects conversion factors for 1997-2050.
Report (PDF) (70 pp, 356 K, EPA420-R-02-014, March 2002)
MOBILE6 Inspection / Maintenance Benefits Methodology for 1981 through 1995 Model Year Light Vehicles Report describes new method for estimating exhaust emission I/M benefits for IM240, Idle, 2500 RPM/Idle and ASM tests.
Report (PDF) (65 pp, 167 K, EPA420-R-01-053, October 2001)
Data & Calculations (XLS) (580K)
Estimating Benefits of Inspection/Maintenance Programs for Evaporative Control Systems This document describes how MOBILE6 calculates the evaporative hydrocarbon emission benefits of an I/M program that includes checks of vehicle evaporative control systems.
Report (PDF) (49 pp. 203 K, EPA420-R-03-001, January 2003)
MOBILE6.1 Particulate Emission Factor Model Technical Description - Final Report This report describes how all of the particulate emission factors and calculations are performed in the MOBILE6 emission model.
(a) Response to Comments (PDF) (34 pp, 105 K, EPA420-R-01-042, July 2001)
(b) Original Report
Full Report (PDF) (167 pp, 2.56 MB, EPA420-R-01-060, November 2001)
Development of Speed Correction Cycles: New Driving Cycles to Measure Effects of Speed and Roadway Type:
(a) Response to Comments, Corrections and Clarifications;
(b) Original Report
This report documents the development of new facility-specific inventory cycles based on real-world driving studies, that will allow for speed and roadway-type corrections to exhaust emission factors.
Report (PDF) (167 pp, 2.56 MB, EPA420-R-01-060, November 2001) Supporting files posted January 2002:
- Figures (XLS) (575K)
- Method Demonstration (XLS) (500K)
- Raw data (DBF) (350K)
- Data field descriptions
Final Facility-Specific Speed Correction Factors This report describes the analysis of the new driving cycle data and presents the resulting speed correction factors used in MOBILE6 for the gasoline passenger car and light duty gasoline truck classes, including the effects of off-cycle driving and the effects of the SFTP on newer vehicles.
Report (PDF) (318 pp, 778 K, EPA420-R-01-009, April 2001)
Development of Methodology for Estimating VMT Weighting by Facility Type This report summarizes the results of work conducted for EPA involving the development and application of methods to estimate certain aspects of on-road vehicle activity (default distributions of VMT by hour, speed and roadway type).
(a) Response to Comments (PDF) (17K, EPA420-R-01-010, April 2001)
(b) Original Report (PDF) (53 pp, 208 K, EPA420-P-99-004, February 1999)
Guidance for the Development of Facility Type VMT and Speed Distribution:
(a) Response to Stakeholder Comments
(b) Original Report
This report offers the EPA's recommendations on how to develop distributions of vehicle miles traveled (VMT) by time of day, facility type and average speed.
Report (PDF) (26 pp, 114 K, EPA420-R-01-025, April 2001)
Spreadsheet (XLS) (731 K)
Comparison of Start Emissions in the LA92 and ST01 Test Cycles This report compares start emissions for two test cycles using data from a sample of five vehicles to determine whether start emissions differ between the two test cycles.
Report (PDF) (20 pp, 105 K, EPA420-R-01-059, November 2001)
Spreadsheet (PDF) (75K)
The Determination of Hot Running Emissions from FTP Bag Emissions This report describes determination of HR505 emissions from FTP data. HR505 is a hot running cycle used to separate running and start emissions.
Report (PDF) (31 pp, 146 K, EPA420-R-01-058, November 2001)
Database (DBF) (1.9MB)
(same data as M6.EXH.001)
Determination of Start Emissions as a Function of Mileage and Soak Time for 1981-1993 Model Year Light-Duty Vehicles This report describes the methodology used to calculate start emissions as a function of mileage and soak time.
Report (PDF) (19 pp, 93 K, EPA420-R-01-029, April 2001)
Exhaust Emission Temperature Correction Factors for MOBILE6: Engine Start and Running LA4 Emissions for Gasoline Vehicles For MOBILE6, the existing MOBILE5 temperature correction factors will still be used. However, they will be applied separately to cold start, hot start, and running LA4 emissions rather than weighted together into an overall FTP correction.
Sensitivity Analysis of MOBILE6.0 Report (PDF) (64 pp, 1.3 MB, EPA420-R-02-035, December 2002) Sensitivity Analysis of MOBILE6.0 This report presents a systematic study of the relative importance of various MOBILE6 input parameters.

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