Climate change has fully entered the public consciousness, but what to do and how fast to do it remains intensely controversial. These and other questions about how to mold transportation policy to help achieve climate goals was the focus of a high level meeting in California in July 2009. Two hundred leaders and experts were assembled from the automotive and energy industries, start-up technology companies, public interest groups, academia, national energy laboratories in the United States, and governments from around the world. Three broad strategies for reducing greenhouse gas emissions were investigated: reducing vehicle travel, improving vehicle effi ciency, and reducing the carbon content of fuels. This book is an outgrowth of that conference.