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 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…
Garrick and Marshall have also previously found that people who live in more sparse, tree-like communities spend about 18 percent more time driving than do people who live in dense grids. And they die more readily—despite old research that implied otherwise. Studies from the 1950s looked at safety in cul-de-sacs and found, as Marshall put it, “You’ll have fewer crashes in the cul-de-sacs. Sure, you’re safer if you never leave the cul-de-sac. If you take into account the entire city, your city might be killing more people.”…
They also found that wide streets with many lanes are associated with high rates of obesity and diabetes. That’s most likely indicative of, as Garrick and Marshall put it, “an inferior pedestrian environment.” Similarly, so-called “big box” stores in a neighborhood indicate poor walkability and are associated with 24.9 percent higher rates of diabetes and 13.7 percent higher rates of obesity.
Dense cities promote walking and biking, so the push for healthier cities fits with the vogue push for active lifestyles—as opposed to gym routines smattered across an indolent existence. Physical activity is not just concerted exercise time and deliberate recreation. It’s about ways of life. For some people, that’s best accomplished by making things inevitably more difficult on themselves in everyday life.
This seems to make some intuitive sense though there are lots of factors likely involved. I’m thinking of Putnam’s Bowling Alone which highlighted a whole range of factors that contributed to decreased civic engagement including sprawl and the rise of television.
But, if such research holds up – and even if it takes some time to confirm things and reach a consensus – such findings could lead to a new/forgotten dimension of selling places and new developments. Part of the appeal of emerging suburbs in the mid-1800s was getting away from the dirty city, a place that was increasingly seen as physically and morally corrupt. Developers sold the suburbs as getting back to cleaner settings that were closer to nature. This research would flip this idea: cities and more urban places promote more movement and better overall health. I imagine anti-sprawl advocates like the New Urbanists would want to jump all over this and add it to their lists of reasons why American sprawl should be halted.