This pie chart shows 2006 percentages of U.S. transportation greenhouse gas (GHG) emissions by vehicle type. Percentages are based on a total of all gases, in total teragrams of carbon dioxide equivalents. The largest sources of transportation GHGs in 2006 were passenger cars (34 percent) and light duty trucks, which include sport utility vehicles, pickup trucks, and minivans (28 percent). Together with motorcycles, these light-duty vehicles made up about 63 percent of transportation GHG emissions. The next largest sources were freight trucks (20 percent) and commercial aircraft (7 percent), along with other non-road sources (which combined, totaled about 7 percent).