One BILLION cars

That's the world population of cars now, and it could double in the next 20 years. This is according to Daniel Sperling, author of the book Two Billion Cars: Driving Toward Sustainability. Sperling was interviewed yesterday on one of my favorite radio shows, Fresh Air.

It's a really interesting conversation about the history of technology advancements and market forces that have influenced the makeup of the car population now, and how we might slow its growth and make electric, hybrid, and hydrogren vehicles take up a larger share in the future.

Car sharing gets a lot of love, of course, but some of his other answers are surprising. He points out the shortcoming of mass transit and promotes bike sharing, paratransit, and other ways to change what he terms "the transportation monoculture."

You should take a listen, even if you're not a policy wonk - these Big Picture questions address important facets of all our lives.

(AP photo via anthonares.net)