Deborah Gordon is a transportation policy analyst who has worked with the National Commission on Energy Policy, the California Energy Commission, the Hewlett Foundation, and with the Chinese government to develop policies for its burgeoning auto fleet. She has also served as the director of the transportation and energy programs at the Union of Concerned Scientists. Daniel Sperling is professor of engineering and environmental science & policy at the University of California, Davis, and founding director of UC-Davis's Institute of Transportation Studies. He also serves on the California Air Resources Board, and has authored 10 books and over 200 technical papers and reports on transportation and energy. They are the authors of the book, Two Billion Cars: Driving Toward Sustainability.