Here's one key to Daniel Sperling's vision for the future of mobility: He doesn't like to drive.

It's not so much that Sperling, one of the nation's most influential transportation thinkers and policymakers, hates sitting behind the wheel (though he does prefer riding as a passenger). It's more that he finds the petroleum-powered, single-occupant vehicle a little, well, uninspiring. His new book, "Two Billion Cars: Driving Toward Sustainability," is a plan for how we can do better.

With co-author Deborah Gordon, Sperling lays out a path to cleaner cars, greener fuels and – the biggest change – a richer menu of transportation options, from "smart" microbuses to shared neighborhood vehicles.

"We can provide a transportation system that's cheaper and provides a better quality of service and more environmental benefits than the system we have now," he said.

Sperling, 57, is the founding director of the Institute of Transportation Studies at the University of California, Davis, and one of the nine members of the state Air Resources Board, which heads California's war on climate change.

He is the air board's acknowledged expert on vehicles and fuels. That puts him in a key position as the state expands its carbon-cutting power in that area.

But at times he's pushed for caution rather than change. Last year, he led a board decision to relax state mandates for all-electric and hydrogen-powered vehicles. It pleased carmakers but drew a furious response from electric-car advocates.

Next month, he stands to swing the debate again as the board takes up the world's first plan – shaped largely by Sperling – to cut the carbon content of vehicle fuels.

Sperling has been thinking for years about many of the policies the air board is now enacting. But when he started work on "Two Billion Cars," in 2000 – about the time he bought his first Toyota Prius – many of his ideas didn't seem likely to reach beyond academia.

Fuel efficiency in the United States hadn't improved since the early 1980s. Detroit was captivated by fast-selling SUVs. And a hodgepodge of policies had first pushed one alternative fuel, then another (remember methanol?), to little lasting effect.

"I was frustrated by the nature of the public debate," said Sperling late last month, swiveling on his chair in a compact UC Davis office that holds six floor-to-ceiling bookshelves and a desk piled with reports. "It was not a very well-informed discussion."

But by the time the book was released in December, the gears had begun to turn. New federal standards are set to improve fuel-efficiency to 35 mpg by 2020, and state officials are pushing for even higher targets. A new state law requires land developments be designed to reduce driving. State regulators are hustling to cut California's greenhouse gas emissions – roughly 40 percent of which come from vehicles – back to 1990 levels by 2020.

The book's timeliness helped vault Sperling into the national eye. He landed an interview on National Public Radio, an op-ed in the New York Times and high-profile speaking appearances from Washington, D.C., to San Francisco.

Last month, he sat across from Jon Stewart for a six-minute spot on Comedy Central's "The Daily Show." After fighting off a laugh attack, Sperling squeezed in pitches for a few of his favorite policies, including a national floor on the price of gasoline.

Much of the book, Sperling said, is informed by conversations over decades with executives in the global auto and oil industries. Those connections are part of what makes his transportation dreams, radical as some are, feel plausible. He knows what drives corporate decision-makers, and recognizes how fast – or how slowly – their companies can realistically change.

"He has been a voice of reason and vision," said David Cole, an industry expert who chairs the Ann Arbor, Mich.-based Center for Automotive Research.

At the same time, Sperling has earned respect from the mainstream environmental community, which cheered his appointment in 2007 to an air board spot held in the past by auto industry insiders.

Call The Bee's Jim Downing, (916) 321-1065.