Vehicle Emissions and Greenhouse Gas Data

The Emissions Inventory program is responsible for collecting the vehicle activity data used to evaluate criteria pollutants, hazardous air pollutants, and greenhouse gas emissions from the transportation sector. These data include vehicle population, vehicle miles traveled, and fuel consumption estimates. Inventories are compiled every three years with the most recent inventory in 2020 available here. Data files are provided in MS Excel format. Download all data files in .zip format.

Vehicle Population data represent state and county level distributions the Department of Environmental Protection compiles from the Bureau of Motor Vehicle registrations based upon July snapshots to correspond with our Emissions Inventory methodology.  Beginning in 2020, vehicle populations will be available annually.  A complete inventory release occurs every three years to coincide with our National Emissions Inventory submittals.  For years in between we will release raw data files as they are generated from our database application.  A methodology is provided to project vehicle populations if inventory years are absent or until actual data are available.

Vehicle Populations by County (xlsx) for the state at the county level with historical tables from past inventories compiled from actual motor vehicle records. UPDATED 05/10/2023 with raw data tables.

Vehicle Populations by Town 2022 (xlsx) are vehicle populations distributed by vehicle class, fuel type, and age distribution at the town level compiled from actual motor vehicle records. UPDATED 05/10/2023 with raw data tables. You can find historical vehicle population data in the compressed zip data files.

Vehicle Population Projection Methods (docx) – Method with example calculations used to project future year vehicle population activity data at the state, county, or town level.

Electric Vehicle Population data includes a complete listing of vehicles captured within our inventories that contain electrification technology used to assist or fully propel a vehicle. Battery electric vehicle (BEV), plug-in hybrid electric vehicle (PHEV), hybrid electric vehicle (HEV), neighborhood electric vehicle (NEV), electric motorcycle (ME), and neighborhood electric motorcycle (NME) population data by make, model, and town. Prior to 2020 all inventories were captured on July 1st of each inventory year.

*NEW* Effective in 2023 we include state, county, and legal city electrification technology summaries along with vehicle make and model trends. The ANNUAL data sets now contain the mail city and zip code information.

Annual Electric Vehicle Data (xlsx) – Contains all electric vehicle population data from 2020 onwards.  The data captures inventories for a complete calendar year. Extra tables are included with mail city and zip code locations. UPDATED 05/05/2023

Mid-Year Electric Vehicle Data (xlsx) – Compiled from our pre-existing inventories where we capture the data on July 1st of each calendar year. It is more limited in that it doesn’t include mail city and zip code information. The data captures inventories from 2015 onwards. UPDATED 05/05/2023

Vehicle miles traveled data represent state and county level distributions by vehicle class (motorcycles, light-duty, buses, etc.) compiled by the Department of Transportation. State and county level projections through 2050 can be used until actual data are available. Also included are annual miles traveled data estimates for each vehicle class. Beginning in 2020 vehicle miles traveled data will be available annually.  

VMT by County (xlsx) actual vehicle miles traveled data by vehicle class by county with DOT modeled projections through 2050. UPDATED 05/05/2023

Annual Miles Traveled estimates (xlsx) - In this estimate, we are following protocols used for our national modeling platforms and applying all the vehicle miles traveled on Maine’s roadways to local vehicle populations. It does not represent odometer mileage reporting from the motor vehicle registrations. This file will be updated every 3 years when our National Emissions Inventory results are available. 

Fuel consumption data are generated using the Motor Vehicle Emissions Simulator (MOVES) modeling application. MOVES is the modeling platform used by the U.S. Environmental Protection Agency (EPA) for our national emissions modeling programs.

Gasoline Fuel Consumption (xlsx) - Conventional E10 gasoline fuel consumption estimates by county, road type, and vehicle class.

Diesel Fuel Consumption (xlsx) - Diesel fuel consumption estimates by county, road type and vehicle class.

Mobile Greenhouse Gas Emission Factors are a subset of emission factors selected from the U.S. Environmental Protection Agency's Federal Regulations for Greenhouse Gas Emissions Standards (Title 40 CFR, Part 98, Table C1 and Table C2), chosen to calculate Greenhouse Gas Emissions where (Emissions = Activity x Emissions Factor). We provide mobile sources emissions factors with all the conversions for the various units of measure typically used to estimate Greenhouse Gas Emissions from vehicle activity data.

Mobile Greenhouse Gas Emission Factors (xlsx) contains mobile sources emissions factors for Carbon(C), Carbon Dioxide (CO2), Methane (CH4), and Nitrous Oxide (N2O) for several different fuels sources (CNG, Aviation Gas, Onroad Diesel, Jet Fuel, LNG, LPG, Motor Gasoline, Residual Fuel Oil, Biodiesel, and Ethanol) for Mass Per Units of Volume (standard cubic feet, gallons) and Mass Per Units of Energy (British Thermal Units(Btu)) Measurements for English or Metric standards (pounds (lbs.), grams (g), kilo grams (kg), metric tons (MT), million metric tons (MMT)). 

For more information contact: Denise E. Cormier,, 207-287-2451