Transportation-related greenhouse gas (GHG) emissions are the fastest growing source of emissions in the U.S., and are currently responsible for almost 30% of the nation's total GHG output. A new ULI report, Moving Cooler, presents different strategies for making our transportation systems more sustainable. It proposes nine categories for improvement, including pricing/taxes, land use and smart growth, transit improvements, ridesharing, intelligent systems, and more. Going beyond other reports of its kind, it not only looks at the costs and effectiveness of different strategies, but considers them in various combinations. Although you have to buy the book, you can get an overview of its findings here.