Our passion for driving what we want, where and when we want, has driven us to the cliff’s edge: Now we must sharply reduce our use of oil-based auto fuels, or face disastrous climate changes.

UC Davis transportation expert Daniel Sperling has a vision of how we can make that transformation and what it will require — revolutionary new cars, fuels and personal behavior — and he is being heard around the world by leaders in government, industry, science, human welfare and conservation.

Among his recent public presentations: an interview on the National Public Radio program Fresh Air.

As of Dateline’s press time, Sperling was scheduled to apppear Wednesday on The Daily Show with Jon Stewart.

Sperling is a professor of civil engineering and of environmental science and policy, and founding director of the UC Davis Institute of Transportation Studies. He is co-author of California’s innovative Low Carbon Fuel Standard and a member of the globally influential California Air Resources Board.

His predictions are outlined in a new book, Two Billion Cars: Driving Toward Sustainability (Oxford University Press), written with co-author Deborah Gordon and with a foreword by Gov. Arnold Schwarzenegger.

The UC Davis News Service recently pulled Sperling out of the policy fast lane for a short conversation about clean cars, green fuels and changing the way people drive.

His comments, shown in video clips, are found on the UC Davis home page at www.ucdavis.edu. The content includes:

The problem in the U.S. — Transportation accounts for one-third of the oil consumed and two-thirds of the carbon dioxide released in the United States. That’s a recipe for trouble.

The problem globally — What happens when the rest of the world gets the same freedom of mobility that Americans have?

The transformation — Expect big changes in the cars we drive, the fuels they run on, and our 80-year-old driving habits.

More information: www. ucdavis.edu.