Mark Vlasic and his family weren't thinking about walkability when they moved into Salt Lake City's east Liberty Park neighborhood several years ago. But its pedestrian-friendly, tree-lined streets and proximity to work, parks and local businesses have enhanced the family's life.
"We've been recreating by biking around the neighborhood. We've discovered a new way of enjoying the city that is becoming part of our family entertainment," said Vlasic, a landscape architect with two teenage daughters. His Browning Avenue home is midway between his office in Sugar House and his wife's downtown workplace. With spiralling gasoline prices driving up the cost of commuting, they have stepped up their use of leg-powered transportation to get to work.
It's hardly surprising, then, that a new University of Utah study suggests that older, walkable neighborhoods like the Vlasics' aren't just convenient and cost effective, but healthier as well. Crunching data on nearly 500,000 Salt Lake County driver licenses, researchers documented a strong correlation between residents' body-mass index and the kind of urban environment they inhabit. Those who live in walkable neighborhoods are leaner than those in newer areas designed around automobiles, according to the study, published today in the American Journal of Preventative Medicine.
"Residents find walking more attractive and enjoyable where there are other walkers, a variety of destinations easily accessible by foot and pedestrian-friendly street networks. People want to walk when it's pleasant, convenient and when there is a destination," said lead author, U. demographer Ken Smith, a professor of family and consumer studies.
Smith's findings dovetail with a recent Utah Department of Health survey that concluded Salt Lake's sprawling suburbs, such as West Jordan, Magna and Kearns, have the state's highest rates of unhealthy weight - nearly two-thirds of adult residents. The survey found denser communities tend to have fewer overweight residents, bottoming out with Salt Lake City's pricey Avenues district at 39 percent.
While these studies do not nail down causal relationships, their policy implications are clear for some officials, such as Salt Lake County Mayor Peter Corroon, grappling with the area's future growth.
"Starting in the 1950s, we went away from the concept of walkable communities. We depend on our cars for transportation. A lot of it has to do with zoning," said Corroon, who lives in the Avenues. "We have to go back to where we were and create a model to building where you can live, work and recreate all within the same community."
Smith's study calculated the body-mass index of Salt Lake County residents, ages 25 to 64, from the heights and weights self-reported on their driver licenses. The scholars keyed this data to 564 geographic census-block units, which they indexed for walkability - measured by density of intersections, percentage of residents who walk to work, and median age of homes.
The researchers found that adding 10 years to the age of a neighborhood decreased obesity risk by 8 percent for women and 13 percent for men. A 6-foot-tall man, on average, weighed 10 pounds less if he lived in a walkable neighborhood; a 5-foot-5-inch woman weighed 6 pounds less. The study also found that your risk of being overweight drops if your neighbors walk to work.
The study's conclusions could be undermined by "confounding" factors, such as residents' income, education, race and age, but they were strong enough for Smith's team to win a $400,000 grant from the National Institutes of Health to further probe the link between obesity and neighborhood. Driver license data has reliability challenges because people might misreport their weight and license addresses don't necessarily reflect where the person has lived, Smith noted. But the low cost and broad coverage of this data set make it a valuable tool for demographic research.
* A center, whether it's a shopping district, a main street or a public space.
* Dense enough for local businesses to flourish and for public transportation to run frequently.
* Mixed income, mixed use, with businesses and residences located near each other.
* Parks and public space.
* Pedestrian-centric design, with buildings close to the street.
* Nearby schools and workplaces.
Learn the walkability index of your neighborhood at http://walkscore.com.