An update of a thought-provoking 2002 report on the effects of sprawl has more data on the negative health effects of this development pattern. The study probes how sprawl affects a person’s well-being (or, alternatively, how connected and compact neighborhoods do). The study finds that urban sprawl does affect health in negative ways, creates more financial demands, and results in shorter lifespans.
This intriguing study examines the costs (financially and physically) and benefits of sprawling development. Findings, from peer-reviewed research, link sprawl to “physical inactivity, obesity, traffic fatalities, poor air quality, residential energy use, emergency response times, teenage driving, lack of social capital and private-vehicle commute distances and times.”
On the other hand, in the 2014 update (Measuring Sprawl 2014), those living in compact and connected metro areas have “greater economic mobility, … spend less on the combined cost of housing and transportation, … have greater options for the type of transportation to take, … [and] tend to live longer, safer, healthier lives than their peers.”
Wondering what sprawl is, according to these researchers? From an executive summary of the first report:
[T]he researchers identified sprawl as the process in which the spread of development across the landscape far outpaces population growth. The landscape sprawl creates has four dimensions: a population that is widely dispersed in low-density development; rigidly separated homes, shops, and workplaces; a network of roads marked by huge blocks and poor access; and a lack of well-defined, thriving activity centers, such as down-towns and town centers. Most of the other features usually associated with sprawl—the lack of transportation choices, relative uniformity of housing options or the difficulty of walking—are a result of these conditions.
In the update, this group of researchers marked development index scores for 221 metro areas and 994 counties in the United States. The four factors first identified were: “residential and employment density; neighborhood mix of homes, jobs, and services; strength of activity centers and down-towns; and accessibility of the street network. These are the essential building blocks of smart growth.”
Close, connected neighborhoods save money; save one’s time; and, in my experience, offer great convenience with a pedestrian ease of access. Shear away that armored vehicle. Build neighborhoods where one might find vitalizing juice or fresh produce at the corner store half a block away.
If you want to see specific leaders and laggards in terms of development style, Streetblogs USA pulled some tables out of the report:
Take a close look at those index scores. They mean more than you may think.
For every 10 percent increase in the index score at the metro level, there is:
a 4.1 percent increase in economic mobility, or the probability that a child born to a family in the bottom quintile of the national income distribution reaches the top quintile of the national income distribution by age 30
a 1.1 percent increase in housing costs relative to income — but a 3.5 percent decrease in transportation costs relative to income. That means the combined costs of housing and transportation fall when communities become more compact. Households in the worst-ranked Hickory, North Carolina, spend a whopping 29 percent of their income on transportation, about two-and-a-half times the percentage San Franciscans spend
a 3.9 percent increase in the walk mode share
an 11.5 percent increase in the transit mode share
Further on, she adds:
At the county level, for every doubling in the index score, life expectancy increases by about 4 percent, or about three years.
A whole host of health and safety risks factor into the link between sprawl and life expectancy. For one, the risk of a fatal collision rises with sprawl. “Counties with less sprawl have more car crashes,” the authors write, “but fewer of those crashes are fatal. For every 10 percent increase in the Index, fatal crashes decrease by almost 15 percent.”
Obesity and body mass index, blood pressure and diabetes also rise with sprawl. Air quality worsens.
Communities can change their built environment and all the health and economic indicators that go with it. They can enact zoning codes to encourage mixed use development, like Santa Barbara did. They can promote downtown residency and reinvestment in existing housing stock, like Madison. They can follow Los Angeles’s example and jumpstart development around transit stations, increasing allowable density and reducing parking requirements in those places.
Density isn’t destiny — unless communities do nothing to change.
Measuring Sprawl 2014
Download the full report including our entire national rankings, quality-of-life findings and methodology. Click here to download the full report.
Measuring Sprawl 2014: Executive Summary
Click here to download the Executive Summary.
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