6/1/2021 · The new vehicle emission rate increased 3 g/mi to 356 g/mi. Fuel economy decreased by 0.2 miles per gallon to 24.9 mpg, or slightly below the record high achieved in model year 2018. Since 2004, CO 2 emissions have decreased 23%, or 105 g/mi, and fuel economy has increased 29%, or 5.6 mpg.