Efforts to improve fuel economy also reduce carbon dioxide (CO2) emissions, but improvements at the low end of the fuel economy spectrum produce the greatest CO2 emissions reductions. A vehicle that gets 10 miles per gallon (mpg) and is driven 15,000 miles per year will produce about 15 tons of CO2 annually. Increasing that fuel economy by 5 mpg to 15 mpg will produce about 10 tons of CO2 annually – a 33% reduction in annual CO2 emissions. As fuel economy improves, there is a diminishing impact on emission reduction. At the high end of the fuel economy spectrum, a 5-mpg improvement from 50 to 55 mpg only yields an improvement of 0.3 tons of annual CO2 emissions.
Note: Based on 15,000 annual miles and regular gasoline.
Source: U.S. Department of Energy and U.S. Environmental Protection Agency’s Fuel Economy Website