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An elderly woman is walking down a several-mile stretch of treeless road. Cars whiz by, going 60 mph in a 45 mph zone. It’s broiling out. If a car hits and kills her, the cause of death would be ruled vehicular trauma. If she died of heat stroke, the cause of death would be heat stroke. Factors the autopsy wouldn’t mention: a lack of tree cover and sidewalks, a lack of public transportation, or the reasons she was walking on that road in the first place.

UCLA professor Dr. Richard Jackson witnessed the senior citizen walking down the busy road that day. She didn’t get hit, but it was an a-ha moment for Jackson—-one documented in Walkable City: How Downtown Can Save America, One Step at a Time, Jeff Speck’s 10-step guide to how to make downtowns more livable.

Speck’s book may produce a few a-ha moments of its own, too. The author, an architect and urban planner, co-wrote Suburban Nation: The Rise of Sprawl and the Decline of the American Dream with Andres Duany and Elizabeth Plater-Zyberk. For some, that book is the manifesto of new urbanism, a movement that promotes the revitalization of cities and urban centers in an effort to stop the plight of urban sprawl. The book also helped him nab a position as the director of design at the National Endowment for the Arts from 2003 to 2007, where he oversaw programming for the Mayors’ Institute on City Design. Though he says he wasn’t “Mr. Walkability” when he started the job, as more mayors brought their case studies to him, he began to grasp that street life played a massive role in the “success” of urban environments.

But while Suburban Nation seemed to be more about cities versus suburbs, Walkable City accepts that some people prefer the ‘burbs to the city. It doesn’t take on the myriad sustainability issues of suburban development. Instead, it focuses on how to make cities better. Speck can summarize the anatomy of a walkable place in a few words: It’s useful, safe, comfortable, and interesting. These four principles explain why some neighborhoods are more attractive to visit, and some urban centers are more robust than others. The book spends about 300 pages expanding on those four principles, and it does so with a balanced mixture of anecdotes and stats, in language that alternates between crunchy-granola idealism and invisible-hand capitalism. But it all serves to illustrate how slight modifications to a city’s uses can make it—-and its inhabitants’ lives—-better.

Speck isn’t anti-car. He owns a vehicle and enjoys driving it. He does, however, see the danger in designing cities for motorists. He dedicates several chapters to the car, mulling over what to do with it and where to put it, borrowing liberally from Donald Shoup’s The High Cost of Free Parking (with Shoup’s permission). But Speck doesn’t push a one size-fits-all approach. He cites a period in the 1970s when cities nationwide were converting streets into pedestrian malls, resulting in failed downtowns. Then he looks at New York City Mayor Michael Bloomberg‘s support of bike lanes throughout the city—-a sweeping effort that has stoked prolonged, heated conflict between car drivers and bicyclists, but has also transformed parts of New York into more livable places.

So while Walkable City does aim to transform downtowns into a place to drive to, rather than through, it has a not-so-ulterior motive: to create armchair urbanists. (Like in D.C., where there’s no shortage of those.) “There are a lot of armchair architects, and people have an opinion about the building going up around the corner,” Speck says. Why shouldn’t it be the same for quality-of-life considerations, like safer routes to the grocery store?