What do we mean when we say that a city is “healthy”? Do we mean that it’s cleaner, safer, and less polluted than others? That its economy is booming? That it spends its taxpayers’ money wisely, on projects that benefit the many over the few? That it prioritizes the building of community—not just in the social but in the physical sense?

Jeff Speck believes that for a city to be described as healthy, it can’t just be one, or even some, of these things; it has to be all of them. And he believes cities can achieve them by committing to the principles of walkability, the idea that communities should be built to meet the needs of pedestrians, not automobiles.

Jeff Speck, city planner and author Will Crooks for Island Press

Speck, an architect by training, altered the course of our national conversation about urban planning six years ago with the publication of Walkable City. Pointed, funny, and acerbic, his book railed against our sprawling automobile-focused culture and made the case for a human-scaled alternative. To historically dry discussions of things like municipal parking policies, congestion pricing, and traffic flow, Speck brought a fresh voice and a no-holds-barred attitude; reading him was a bit like reading Anthony Bourdain, if the late food writer and TV host been more interested in sidewalk regulations than sidewalk cafes.

Walkable City became something of an evangelizing tool for advocates of smart growth and pedestrian-friendly communities, with adherents zealously handing out copies of the book to friends and acquaintances—“like tabs at a Grateful Dead concert,” as Speck puts it (very Speckishly, I might add). But while Walkable City may have been terrific at summarizing a new philosophy, it wasn’t necessarily the best how-to guide for, say, swaying a city council member to narrow traffic lanes or persuading a mayor to install speed bumps or a new traffic circle.

The book cover for Walkable City Rules Island Press

Enter Speck’s new book, Walkable City Rules: 101 Steps to Making Better Places (Island Press). Filled with the photos, graphics, and charts that many of his fans felt were missing from the last book, the new volume comprises 101 mini-chapters, each of which elegantly distills a single precept from his philosophy over the course of just two pages. If the first book was written to convince you—the reader who has already evinced a keen interest in urban planning—of the manifest benefits of walkability, the second book, in Speck’s words, “is meant to help you convince other people.”

Those benefits are walkability’s demonstrably positive effects on a city’s wealth, public health, equity goals, sense of community, and, of course, climate change mitigation. My conversation with Speck took place shortly after the U.N. Intergovernmental Panel on Climate Change released its much talked-about report detailing the consequences of allowing global temperatures to rise more than 1.5 degrees Celsius. Naturally, we discussed how investing in walkability can help cities lead the way in cutting greenhouse gas emissions. Speck had a lot to say.

“If you count both first-order and second-order impacts, I think it’s absolutely clear that the car-dependent lifestyle—one that both is caused by and also causes sprawl—is the number one contributor to our destruction of the human habitat,” Speck told me. “The first-order impacts, of course, are all the emissions that come from driving, and the other pollutants that come from it, from the petroleum in our asphalt to the acid in our car batteries. But as my friend [New Yorker staff writer] David Owen has pointed out, the biggest contribution that driving makes to our environment is that it causes us to spread out. And when we spread out, we consume more land; we require more infrastructure per capita; there’s more sewers and electrical lines per person. We consume just so much more.”

Speck’s new book can be thought of as a primer on how to free our cities from the tyranny of the automobile, moving them closer to their original identities as urban villages that foster community interaction by encouraging people to stroll sidewalks and linger in public spaces. Among other things, it focuses on promoting dense, mixed-use development, ramping up bike infrastructure, and right-sizing lanes (in both width and number) to lower traffic speeds and increase safety. And it makes clear that in this era of near-constant bumper-to-bumper traffic congestion, quick and dependable mass transit—and not cars—is what offers citizens the greatest amount of personal freedom.

In dendritic sprawl, most streets are cul-de-sacs and loops, so connectivity falls to a small number of collector streets that are designed as highways. Alex S. MacLean, Landslides Aerial Photography

Way back in 2000, Speck coauthored the seminal Suburban Nation: The Rise of Sprawl and the Decline of the American Dream, which laid the theoretical groundwork for a New Urbanist movement that championed density, walkability, and shared public space as the bedrock elements of community. While it may not be accurate to say that the author has softened his stance on sprawl since then, it’s probably fair to state that he has come to accept the fact of its continued existence—and would rather spend his time and energy these days on making suburbs and exurbs greener, smarter, and healthier than simply excoriating those who choose to live there.

Speck sees an example of what he deems “training-wheel urbanism” in the current vogue for open-air, mixed-use “lifestyle centers.” These giant mixed-use developments, often found in exurbs, typically combine shopping, apartments, restaurants, cinemas, hotels, and public parks or fountains, all designed to mimic the dynamism and vitality of a city streetscape. The success of these projects outside Atlanta, Houston, Denver, and other places signifies the public’s deep desire, be it expressed or latent, to have the walkable-city experience even though they may be “surrounded by the miasma of sprawl,” in Speck’s words. And he’s convinced that most suburbs built before World War II are sitting on economic gold mines in the form of abandoned Main Streets that are ripe for rediscovery and resuscitation along walkable, New Urbanist lines.

Speck and his firm keep quite busy these days consulting with cities large and small, studying traffic patterns, measuring sidewalk and lane widths, and helping city managers find new ways to incorporate walkability. But he sounds sincere when he says that he hopes his new book will put him out of a job. “I don’t care if I never do another walkability study again,” he says. “Not so long as lots of other people are doing them. I’d much rather be designing buildings!”

onEarth provides reporting and analysis about environmental science, policy, and culture. All opinions expressed are those of the authors and do not necessarily reflect the policies or positions of NRDC. Learn more or follow us on Facebook and Twitter.