Reproduced from Department of Energy; Chart: Axios Visuals
New data from the Energy Department in its latest "Transportation Fact of the Week" series helps underscore one reason why cutting carbon emissions from transportation is a tough nut to crack.
The big picture: The number of cars on the road and vehicle miles traveled have mushroomed compared to population size over the decades.
The bottom line: Carbon emissions from transportation are now the nation's largest source.
Go deeper: Analysis shows U.S. energy carbon emissions spiked in 2018
