In the following interview, we speak with Jeff Speck, author of Walkable City: How Downtown Can Save America, One Step at a Time. Speck is an architect and city planner in Washington, D.C., oversaw the Mayor's Institute on City Design, and served on the Sustainability Task Force of the Department of Homeland Security.

We discuss the fact that walkability is a matter of making driving optional in urban areas. As Speck explains, that doesn't mean owning or driving a car is wrong. Instead, the goal is for driving to represent just one of many transit options, allowing those who prefer to live without a personal vehicle to do so.

A transcript follows the video.

Isaac Pino: I think you, yourself, mentioned that you just recently purchased a car. You point out that there is a role for automobiles.

Jeff Speck: I recently purchased a bigger car.

Pino: An SUV. I hope you walked to the Fool from D.C., though.

Speck: I biked here from Northwest D.C., because I hadn't done that in a while. It's a nice day, and I thought that would be fun. Now that you've accused me, you can let me excuse myself.

I had mentioned I don't just have a car, I have an SUV. The reason I have an SUV is that my kid's in a charter school and we need to carpool so my wife can drive less, and the only way to carpool is to have the seven seats, so we have an SUV.

I write about this in the book, about our decision to eventually buy a car, after living without one for seven years in D.C., including two years with a kid. I'm sure some of you had the same experience. It's perfectly viable. At least until we had the second kid, it was perfectly viable to live without a car.

The whole point is, the walkable cities are driving-optional cities. In some cities like New York, it might be prohibitively expensive to keep a car, but in most of them you still have that option. The point is that it's one option among many, in a landscape that offers you that choice.

We lived for many years without a car. We'll live again without a car someday. Now is a time in our life when it's useful to us. We're not breaking any rules, even philosophically.

I think it's important to point that out, because some people -- especially some of my admirers, who send me anonymous emails -- think that I think it's wrong to own a car, or that this is an ideological position I'm taking. It's strictly a practical position.