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Do We Look Fat in These Suburbs?
People in dense cities are thinner and have healthier hearts than people in sprawling
subdivisions. New research says the secret is in the patterns of the streets.
James Hamblin Aug 13 2014, 8:15 AM ET
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.
Healthiest city designs, from best to worst
(Journal of Transportation and Health)
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
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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.
Three street networks: Organic
(Seville), grid (midtown Manhattan),
and hierarchical-Tree (suburban
Atlanta) (Frank et al., Health and
Community Design)
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.”
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
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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." I got the impression he could go on about
cul-de-sacs.
68 percent of Americans are overweight or obese, which means that someone you know is
overweight or obese. Most people don’t get the CDC’s minimum recommended amount of
physical activity. Americans spend more time driving every year. So it is logical to conclude, as
Garrick and Marshall do in their paper, “The role of the street network and how we put together
the bones of our communities should not be overlooked as a potential contributing factor to
health outcomes.”
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.
As neighborhoods gentrify, people are pushed out of the walkable grids.
“Taken together these findings suggest a need to radically rethink how we design and build the
streets and street networks that form the backbone of our cities, towns, and villages,” Garrick
said in a press statement. “This research is one more in a long line that demonstrates the myriad
advantages of fostering walkable places.”
"It's nice to make more of these connections,” Marshall told me, tonally foreshadowing the
inevitable correlation-is-not-causation caveat, “but it's hard to say that these kinds of
neighborhoods cause good health."
It’s true that people who like to walk and bike might be choosing to live in denser
neighborhoods, and that may be all there is to this relationship. But on that note, there a lot of
people who don't really have a choice where they live. They can't afford to live in the hearts of
big grid cities. “A lot of poor people are getting forced out of the walkable urban scene,”
Marshall said. In a reversal of the 1950s' “white flight,” many cities are seeing gentrification that
is pricing out poor neighborhoods.
Others stranded are kids, who often don't realistically have the option to walk to school. They
have to get on a bus.
So are health factors influencing city planning?
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"There is a push in that direction, but I still wouldn't say it's really integrated into what people
are doing,” Marshall said. “If you're looking to buy a new house, I think very few people are
cognizant that there might be long-term health differences between one neighborhood and the
other. You might hear about it in terms of things like fracking or living near a highway. The
obesity epidemic is becoming a national crisis, but almost nobody connects that with
neighborhood design. The connections we're making there are all about food and exercise. But if
we build neighborhoods where exercise is part of people's daily routine, you would think that
could go a long way."
Indeed. “Life is a bunch of intersections,” I said. But I don’t think he heard me.
Questions:
1. Why are the professors Garrick and Marshall considered “anti – cul de sac”. What have their studies
suggested about older denser cities compared to new modern cities?
2. What are the 3 fundamental measures of street networks?
3. What health concerns are proven lowered by more dense and connected road networks?
4. What are the 3 methods of street design from oldest to most modern? Include an example of each.
5. What was the 1950s argument that was in favour of the cul de sac over the grid system?
6. What is the current argument now supporting the resurgence of the grid system?
7. What other characteristics of the new urban environment are thought to contribute negatively to
our health?
8. Why are the poor most susceptible to living in the places that are not considered “walkable”?
9. Why are children also subject to the negative effects of walkability?
10. Do you think people consider their long-term term health when deciding on a place to buy or build
a home? Should they? Why or why not.