Giving Compass' Take:

• Laura Bliss reports that researchers have mapped urban sprawl, revealing places that are less connected and therefore less healthy. 

• How can funders use this tool to identify communities that could benefit from improvements? 

• Read about what happens to farmland when urban sprawl encroaches. 

A connected street is a healthier street. Neighborhoods with more short links and intersections—and fewer dead-ends and cul-de-sacs—have lower rates of obesity, diabetes, and heart disease, researchers have found. In part, that’s because they promote walking and biking.

So what does it mean that the world is growing less connected?

A new study published in the Proceedings of the National Academy of Sciences charts a worrying global shift towards more-sprawling and less-hooked-up street networks over time.

Adam Millard-Ball, a UC Santa Cruz professor of environmental studies, and Christopher Barrington-Leigh, a McGill University economist, examined 28.6 million miles of streets across every continent, using public data from OpenStreetMap as well as historic satellite imagery. They built an algorithm to identify various characteristics of connectivity, such as the number of cul-de-sacs, the length of unbroken street links, and how long it takes to walk to key destinations.

Who cares? Apart from the fact that spread-out street networks tend to be less healthy for the people who live on them, they also create a greater burden on society, the researchers argue. Developers building new spread-out neighborhoods in fast-growing cities don’t account for the costs—in time, fuel, and greenhouse gas emissions—associated with such car-centric patterns. But those costs exist, and as the map shows, building streets that require them creates a pattern that persists over time. That, in turn, erects barriers that prevent cities from encouraging their citizens to adopt more sustainable ways of getting around, and living.

Read the full article about urban sprawl by Laura Bliss at CityLab.