Just seeing someone wearing a Fitbit makes me nervous. I'm told I have a tendency to become “obsessive.” A count of steps or calories burned would be a destructive competition, just one more thing haunting quiet moments telling me I could be working harder, doing more. Pedometers are an invasion to be absolutely avoided, certainly never sought out or, least comprehensibly, given as a "gift."
A decade ago when I was studying in Venice, Italy, though, I did wear a pedometer. It was for science. I was part of a study that compared health behaviors in the U.S. and Italy—where people eat pasta and drink wine long into the night and never die. So I wore the pedometer reluctantly for a while in North Carolina, and then for while in Venice. And, guess what. People walk more in Venice. It is extremely difficult to drive in Venice. There are just no cars or roads.
Is that all it takes to make a healthy city? My professor Paolo was a native Venetian who, as a middle-aged adult, had never driven a car. He had, though, managed to fall into the canals on three separate occasions in his life. The lagoon-water of Venice is stagnant and loaded with sewage, so pedestrianism has its own health risks.
In places where there are streets, the particular effects of their layout on health are less known. But, like so many environmental factors whose health influence might not be readily apparent (e.g. the trees that save us billions of dollars in medical costs), they seem to be worth considering.
Norman Garrick and Wesley Marshall are assistant professors of engineering at the Universities of Connecticut and Colorado, respectively, and they are making names for themselves among the anti-cul-de-sac crowd.
In prior research, Marshall told me, they found that in the most extreme cases “older, denser, connected cities were killing three times fewer people than sparser, tree-like cities on an annual basis." Of course, people walk and bike more in dense cities, but the research on actual ties to health outcomes is scant. So Garrick and Marshall, along with Daniel Piatkowski at Savannah State University, took on and have just completed a large study of how street networks might influence our health.
They looked at the three fundamental measures of street networks—density, connectivity, and configuration—in 24 California cities, and compared them with various maladies. In the current Journal of Transport and Health, Garrick and Marshall report that cities with more compact street networks—specifically, increased intersection density—have lower levels of obesity, diabetes, high blood pressure, and heart disease. The more intersections, the healthier the humans.
“It might not be common for people to explicitly contemplate health when selecting a place to live,” Garrick and Marshall write, “but this research indicates it is worth considering.”
And people are starting to consider it.
The original city design was really no design at all. Known as “organic,” it is the medieval pattern we see throughout many of Europe’s haphazardly still-thriving cities. Then, for centuries during and after the Renaissance, the rectilinear grid was the gold standard in city design. But in the twentieth century came what Garrick and Marshall call a complete overhaul—a shift toward the branching tree model of the modern subdivision, which was optimized for the great horseless carriage.
Centuries of compact and connected cities rapidly gave way to sparse, dendritic, “hierarchical” street networks. These layouts afforded the luxury of a quiet cul-de-sac with space for miniature mansions and lonely pools in every backyard. As Emily Badger at CityLab recounted in a merciless takedown of the cul-de-sac, the U.S. Federal Housing Authority published technical bulletins in the 1930s that “painted the urban street grid as monotonous, unsafe, and characterless.”
As with people, calling a neighborhood characterless cuts even more deeply than calling it unsafe.
Illustrations of grid neighborhoods and hierarchical neighborhoods in said pamphlets bore the labels “bad” and “good.” The FHA’s design preferences “evolved into regulation. From the 1950s until the late 1980s, there were almost no new housing developments in the U.S. built on a simple grid.”