According to the U.S. Environmental Protection Agency, more than half of the air pollution in the nation is caused by mobile sources, primarily automobiles.

The combustion of fossil fuels. such as gasoline and diesel to transport people and goods is the second largest source of CO2 emissions, accounting for about 31% of total U.S. CO2 emissions and 26% of total U.S. greenhouse gas emissions in 2010.

According to the Environmental Protection Agency, driving a car is typically a person's most polluting daily activity.