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., who oversaw the Mayors' Institute on City Design and served on the Sustainability Task Force of the Department of Homeland Security.

We discuss why epidemiologists, economists, and even environmentalists now recognize the benefits of urban living, and look at how walkability in downtown areas further improves our health and wealth while benefiting the environment.

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Isaac Pino: All right, folks, let's get started. Thanks for coming, and, Jeff, thanks for being here as well. Welcome to The Motley Fool.

Just as a little primer, Jeff Speck is an architect and city planner in Washington, D.C. His new book, Walkable City: How Downtown Can Save America, One Step at a Time, discusses the importance of walkable neighborhoods in creating prosperous, dynamic, and healthy American cities. He is the coauthor of Suburban Nation, as well as the Smart Growth Manual.

As director of design at the National Endowment for the Arts from 2003 through 2007, he oversaw the Mayors' Institute on City Design, and prior to joining the Endowment, Mr. Speck spent 10 years as director of town planning at Duany Plater-Zyberk & Company, a leading practitioner of the New Urbanism, where he led or managed more than 40 of the firm's projects.

Jeff also serves as a contributing editor to Metropolis magazine, and on the Sustainability Task Force of the U.S. Department of Homeland Security. Thanks for being here, Jeff.

Jeff Speck: Thank you for having me.

I should say, on that topic, I just received a letter in the mail from the Secretary of the Department of Homeland Security, that thanked me for chairing the Task Force on Sustainability, but I didn't chair the task force.

Isaac: Always good to get credit for something you didn't do.

Speck: I was going to send it back and say, "Can I have an accurate letter?" and I said, "You know, this is going to look really good, framed, on my wall."

I was just on the Task Force. I didn't chair it.

Isaac: I guess your most recent project, the most recent endeavor, is writing the book, Walkable City: How Downtown Can Save America, One Step at a Time. I see what you did there with the title. It's a great pun.

Speck: Get it?

Isaac: Let's start with that. What is the case? Why do we need walkable cities in America?

Speck: The answer to that question is the one-hour lecture I usually like to give. And seeing that we have one hour...

Isaac: I'm done.

Speck: Yeah. You can take my coffee and go.

The book is organized -- Thank you all for coming, by the way. It's nice to see such a nice crowd. I was mentioning to my hosts that, out of the goodness of my heart, I gave a talk on Monday at the Georgetown Senior Center. I was the lunch entertainment. I showed up, and the six of them who were there apologized for the small crowd, and then two of them fell asleep while I was talking.

Isaac: Something we'll try to prevent.

Speck: It was my Purim mitzvah. That's what I was doing. What was your question, again?

The book -- which could be retitled Everything I Know, and if it's not in the book I don't know it, so just refer to the book -- is essentially two parts.

The first part is the argument "Why walkability?" As if we need to convince people, but there are still a lot of people, especially if you look at the now anonymous and not-so-anonymous emails I've been receiving, there are still people who need convincing, or who think that it's some sort of Communist plot; as if the Federal government didn't build the highways. Like individuals, we all built these highways ourselves, with sticks and hammers.

The first part of the book is the argument "Why walkability?" and I lay out three reasons that are given by three different groups who people take more seriously than planners, as to why our cities need to be more walkable.

The second half of the book is "The 10 steps of walkability," and we'll get into that, I suppose, at some point, but that's the How.

The Why is this litany, if you will -- or litanii -- three litanies that I mostly learned from other people because my specialty is the How. My specialty isn't the Why.

What happened is, being a planner and a designer, and someone who knew that they preferred pedestrian-oriented and transit-oriented older communities, or newer, better communities, over automobile-oriented sprawl, but didn't really...

The reasons that we preferred it were aesthetic reasons: Traditional neighborhoods look better, traditional neighborhoods feel better. Social reasons: We had a strong feeling, and it's only begun to be documented, that people actually are happier and lead more social or socially productive lives in traditional communities, over sprawl.

There's a great book on that called Bowling Alone, by Robert Putnam, a Harvard professor, that some of you might know.

Our arguments were principally social arguments, aesthetic arguments. Not that many people were listening. Then three things happened.

The epidemiologists started saying, "Suburban sprawl is killing us, and we're actually going to live healthier lives in cities."

The economists, some of whom may be in this room, were saying, "Actually, cities make you more productive," but also "Cities are the future" in terms of the choices that people have been making about what they want out of their living environment and their working environment, and we can talk about that all day.

Then the third group was the environmentalists, who came to this 180-degree turnabout, where for years, for generations, really since America's founding, to the degree that there was an environmental movement, it was an anti-city movement and a pro-country movement, as embodied by the Sierra Club ethos, as embodied well before that by even Thomas Jefferson, who said -- he was notoriously anti-city -- and he said, "Cities are pestilential to the morals, the liberties, and the health of man, and if we continue to pile upon ourselves in cities, as they do in Europe, we shall become as corrupt as they are in Europe, and take to eating one another, as they do there."

Isaac: That sounds graphic.

Speck: He had a sense of humor, I suppose.

But the environmentalists started measuring carbon, not per square mile, but per household. I think now, as your minds work, you realize what that means: All those maps, that were red around the cities and green in the countryside, flipped.

Now, if you map cities in terms of carbon output per household, if you map  metropolitan areas in terms of carbon output per household, they're greenest at the center and reddest at the edges, in terms of each of our individual contributions to climate change, to pollution, to all those things.

I should say, overlapping the health discussion with the environmental discussion, 14 people die a day from asthma in the U.S. It's not that many, but it's three times what it was in the '90s, and it's all from tailpipe exhaust. I'm exaggerating, but it's principally the fact that we're driving more and the way that we've come to design our cities around the mandate of automotion has had that sort of impact, both on the environment and on our health.

The epidemiologists have reason after reason about why cities, or I should say "traditionally organized communities" -- towns, villages, cities, but the opposite of sprawl -- are much healthier for us. The principal one is the obesity epidemic, which for many years has been associated with diet, and properly so, but the most recent tests and studies, including one in England that was called "Gluttony vs. Sloth," compare the relative impact of diet and inactivity on the health of our cities or communities, countries.

Study after study that compares those two things demonstrates very clearly that inactivity has a much greater impact. We now have 1 out of 3 kids that are born since 2000 will become diabetics, according to the medical profession. We have the first generation of kids who are expected to live shorter lives than their parents, and it's principally because what we planners call the Useful Walk has ceased to exist.

Now you might walk around the cul-de-sacs for exercise, or drive to the gym to get on the treadmill, but the idea of walking to the soccer game, walking to the baseball game, or for us, as we grow, walking to work, walking to school, has gone away. In fact, when I was a kid, half of us walked to school. Now, 15% of kids walk to school.

Obesity, of course, is not the problem. It's all the other diseases, like diabetes, that obesity causes.

But that, in a sense, pales next to all the lives we're losing in car crashes, which we kind of take for granted. We naturalize the fact that it's just a risk of living, to have all these automotive deaths, but Germany has half the automotive deaths that we do, and New York City has half the automotive deaths that Germany does, because of the way that people live and walk and drive less in New York City.

Isaac: Per capita, of course.

Speck: Yes, excuse me. Per capita.

In fact, New York has saved as many lives, since September 11th, in traffic, as were lost on September 11th. If the whole country shared New York City's traffic death rate, we'd save 24,000 lives a year. It's amazing.

There's compelling health reasons, which I've just touched on. There's the environmental reason. And then there's this wonderful list -- I won't take long, but there's several different angles of looking at the economic question, but the biggest part of it is to look at the demographics of the country and the fact that the biggest cohort is the baby boomers, and the second biggest cohort is the millennials.

Almost everything in between is almost tiny. There's this narrow waist on this hourglass curve. I'm in that narrow, statistically insignificant area. I'm a parent of young children, but of the 100 million households that are supposed to form in the next dozen years, 88 million of them are expected to be childless. Right now, there are more families with dogs than families with children.

Five million Americans lived alone in 1950. Guess how many Americans live alone now? Thirty million.

These are people who don't need yards, don't want to take care of a big house, don't need schools -- what everyone's pushing for -- we're all fighting for better schools. They need what the city has to offer, but they're only going to want to move to a city that actually allows them to have that viable life without being tied to the automobile, because as you get older, particularly as the baby boomers get older, like my parents who just moved for this reason, they want to live in a place... it's called a "naturally occurring retirement community," a NORC.

Isaac: Sounds wild.

Speck: They want to live in a place where they're not dependent on the automobile.

Then you have millennials, many of whom are probably in this audience, who grew up idolizing the city, if I can say this.

When I was growing up we were watching Happy Days, The Brady Bunch, The Partridge Family -- and by the way it was the economist Chris Leinberger who made me realize this -- the kids growing up, the millennials were watching Sex in the City, Seinfeld, Friends, so their whole outlook as to what's normal and good and fun is urban, and that wasn't the case for my generation.

It used to be, in the '70s, 1 out of 12 19-year-olds didn't have a driver's license. Now 1 out of 4 19-year-olds doesn't have a driver's license, so you have all these social -- both in terms of what people need, and in terms of what people want -- you have these reasons why walkable cities will solve their problems.

I'm going to stop because you haven't spoken much.

Isaac: That's perfectly fine.

Speck: But there are much stronger and, in a sense, more compelling arguments about what it does to the economic health of a community to have less dependence on driving.

One of my favorite passages in the book talks about Portland, and how much people in Portland benefit because they're actually driving less than they used to, because of the way they've designed their city. But you can buy the book to read that.