GHG emissions from transportation in the U.S. 1990-2019, by vehicle type

Passenger cars in the United States emitted 762.3 million metric tons of carbon dioxide equivalent in 2019. This made passenger cars the main source of transportation-related greenhouse gas emissions in the U.S. that year. The second most polluting mode of transportation in the U.S. are medium-and heavy-duty vehicles, which produced the equivalent of 444.4 million metric tons of carbon dioxide. Emissions from heavy-duty trucks have increased significantly since 1990. The U.S. accounts for an estimated 18 percent of global road freight CO2 emissions.