This report examines the prospects for substantially reducing the greenhouse gas (GHG) emissions from the U.S. transportation sector, which accounts for 27 percent of the GHG emissions of the entire U.S. economy and 30 percent of the world’s transportation GHG emissions. Without shifts in existing policies, the U.S. transportation sector’s GHG emissions are expected to grow by about 10 percent by 2035, and will still account for a quarter of global transportation emissions at that time. If there is to be any hope that damages from climate change can be held to moderate levels, these trends must change.

This report shows that through a combination of policies and improved technologies, these trends can be changed. It is possible to cut GHG emissions from the transportation sector cost-effectively by up to 65 percent below 2010 levels by 2050 by improving vehicle efficiency, shifting to less carbon intensive fuels, changing travel behavior, and operating more efficiently. A major co-benefit of reducing transportation’s GHG emissions is the resulting reductions in oil use and improvements in energy security.