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Vehicle Emissions and Greenhouse Gas Data

Program Overview

The Emissions Inventory Program collects vehicle activity data used to evaluate criteria pollutants, hazardous air pollutants, and greenhouse gas emissions from the transportation sector. Core datasets include vehicle population, vehicle miles traveled (VMT), and fuel consumption. Inventories are produced every three years with the most recent inventory in 2023 available here. All files are provided in MS Excel format. 

Vehicle Population Data

Vehicle population data represent state- and county-level distributions compiled from the Bureau of Motor Vehicle registrations using July snapshots to align with Emissions Inventory methodology. 

Beginning in 2020, vehicle populations are available annually. 
A complete inventory is released every three years for the National Emissions Inventory (NEI) submissions.
In interim year, raw data files are released as generated.
A projection methodology is provided for years without inventory data.

2025 Vehicle Populations (xlsx) - County-level vehicle populations with trends from past inventories, with Town-level vehicle populations by vehicle class, fuel type, and age distribution. UPDATED 02/12/2026 with raw data tables.

Vehicle Population Projection Methods (docx) – Methodology and example calculations for projecting future vehicle populations at the state, county, or town level.

Electric Vehicle Population Data

Electric vehicle population data include all vehicles in the inventory that use electrification technology to assist or fully propel the vehicle. Categories include the 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) with counts by make, model, and town. Prior to 2020, all inventories were captured on July 1 of each year. In 2023, state, county, and legal city electrification technology summaries along with vehicle make and model trends were added to the reports.

Annual Electric Vehicle Data (xlsx) – Full-year EV population data from 2020 onward, including mail-city and ZIP code information. UPDATED 02/09/2026.

Mid-Year Electric Vehicle Data (xlsx) – July 1 inventory data from 2015 onward. Does not include mail-city and ZIP code information. UPDATED 07/30/2025.

Vehicle Miles Traveled (VMT) Data

VMT data represent state- and county-level distributions by vehicle class (motorcycles, light-duty, buses, etc.) compiled by the Department of Transportation. Projections through 2050 are provided until actual data becomes available. Annual VMT data are available beginning in 2020.

2025 VMT by County (xlsx) - Actual VMT by vehicle class and county with DOT projections through 2050. UPDATED 07/30/2025.

Annual Miles Traveled Estimates (xlsx) – Estimates applying all VMT on Maine roadways to local vehicle populations, following national modeling protocols. These estimates do not represent odometer readings. Updated every three years with NEI results.

Fuel Consumption Data

Fuel consumption estimates 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 by county, road type, and vehicle class.

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

Mobile Greenhouse Gas Emissions Factors

These emissions factors are selected from EPA’s Greenhouse Gas Emissions Standards (40 CFR Part 98, Tables C1 and C2) and are used to calculate emissions using:

Emissions = Activity x Emissions Factor

The dataset includes emission factors for Carbon (C), Carbon Dioxide (CO₂), Methane (CH₄), and Nitrous Oxide (N₂O) across multiple fuel types (CNG, aviation gas, on-road diesel, jet fuel, LNG, gasoline, residual fuel oil, biodiesel, ethanol). Factors are provided in mass-per-volume and mass-per-energy units, in both English and metric measurements.

Mobile Greenhouse Gas Emission Factors (xlsx) - contain mobile-source emissions factors and unit conversions.

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