Car-centered sprawl shortens northwesterners’ lives because it contributes to some of the region’s leading health risks, reports Cascadia Scorecard 2006: Focus on Sprawl and Health, an annual progress report on the Pacific Northwest released today by Sightline Institute (formerly Northwest Environment Watch).

Residents of low-density, residential-only sprawling communities are more likely to die in car collisions, which kill around 2,000 northwesterners a year; and they are also more likely to be obese, which increases the risk of many chronic diseases. British Columbia—which has the region’s best record for curbing sprawl—has a car-crash fatality rate that’s one-third lower than that of the Northwest states and an obesity rate that’s nearly one-half lower.

“The toll from car crashes and obesity-related disease is a tragedy that’s largely overlooked because it unfolds slowly,” said Clark Williams-Derry, research director for Sightline and lead author of the report. “But this tragedy is not inevitable. Simple solutions—such as giving people the tools to drive less by encouraging more compact, walkable communities—could make Cascadia’s communities safer and healthier.”

This year’s Scorecard examines the impact of community design on several health trends, including car collisions, physical activity, obesity, and air pollution. Studies have found that residents of compact areas—where homes are mixed with stores and services and the street network is designed for walking—are less likely to be obese; suffer substantially fewer chronic illnesses such as diabetes, lung disease, and hypertension; and have a lower risk of dying in a traffic accident because they drive less.

Key findings from the report include:

High rate of car-crash fatalities: Car crashes are the leading cause of death under age 45 in Cascadia, with a death toll of about 2,000 northwesterners annually (1,600 in the states); another 100,000 northwesterners are injured. Studies show that residents of the densest communities drive less and face the lowest per capita risk of dying in a traffic accident. King County, for example, is the most urban county in Washington state and also has the state’s lowest car-crash fatality rate. (See traffic-fatalities map.)

Transit safer: Compact, walkable neighborhoods further protect drivers and pedestrians because traffic tends to move more slowly than on suburban arterials, lessening the severity of collisions. Also, residents of compact communities usually have more access to transit. Mile for mile, riding a bus is more than 10 times safer than driving a car.

Obesity growing. More than 1 in 5 residents of the Northwest states are obese, a rate that’s doubled since 1990. Recent estimates place the US death toll from obesity-related ailments at 112,000 per year, which indicates that obesity kills some 4,300 residents of the Northwest states a year (2,300 people in Washington, 1,500 in Oregon, and 540 in Idaho).

Sprawl linked to obesity and physical inactivity: Neighborhood studies in greater Seattle, Atlanta, and San Diego have found that living in compact neighborhood with good walking facilities reduced the odds of being obese, while increasing levels of physical activity, especially walking.

A study in King County, Washington, for example, found that pedestrian-friendly neighborhood design was associated with up to a one-point reduction in the body mass index, which can translate in up to 7 fewer pounds of extra body weight. And other studies have found sprawling cities and counties have more obesity and chronic illness than more-compact places.

The BC advantage: British Columbians are about half as likely to be obese as residents of the Northwest states (12 percent compared to 21 percent), one-third less likely to die in a car crash, and live an average of more than two years longer. If BC were an independent nation, it would have the second longest lifespan in the world, trailing only Japan. One possible factor? BC’s cities—Vancouver and Victoria—are by far the region’s most compact.

Hefty economic costs: According to National Safety Council figures, car crashes may drain the Northwest states’ economies of approximately $8 billion per year, or more than $700 per resident, including medical treatments, lost productivity and wages, and other costs. The total costs of obesity and physical inactivity may top $11 billion per year in the Northwest states.

Solutions for health: Cascadia Scorecard highlights policy innovations to improve northwesterners’ health and safety, including: fostering a blend of stores and services in residential areas; encouraging foot traffic by investing in sidewalks and interconnected streets; easing parking requirements; allowing more development in cities; and requiring new development to pay its way for infrastructure. (See solutions fact sheet.)

The report also recommends assessing the health impacts of potential transportation projects before deciding to build. “If we designed our roads and neighborhoods with health in mind, we might make very different choices,” said Sightline’s Williams-Derry.

Dr. Lawrence Frank, Bombardier Transportation Chair at the University of British Columbia, said there are major activities underway in the Seattle area to do just that. “A King County project (LUTAQH) is developing a health impact assessment tool to measure if, for example, a zoning change would promote walking and other physical activity, or whether a roads construction project would increase air pollution.” Frank is leading the effort and has led several recent studies on health and the built environment noted in the report.

Compact, well-designed communities may also contribute to cleaner air, because residents of denser neighborhoods drive less and emit fewer troublesome air pollutants. And emerging research suggests that walkable community design may foster stronger ties between community members.

In addition to its findings on sprawl and health, Cascadia Scorecard 2006 reports the Northwest’s progress in five other trends critical to its future, including energy use, wildlife, population growth, pollution, and economic security. Overall, Cascadia improved its “score” in 2005, with gains in human health, economy, and energy efficiency. But the Scorecard’s new wildlife indicator suggests the region needs to better protect key species such as salmon, greater sage-grouse, and orcas.

Sightline Institute is an independent, Seattle-based nonprofit research and communication center that monitors progress toward a sustainable economy and way of life in the Pacific Northwest. The Cascadia Scorecard is available at

June 21, 2006