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We Are Public Health Postcard

We Are Public Health, November 2014.

We Are Public Health 2014-07

We are public health.
We use data to project the health benefits of active transportation.

In 2009, the Oregon Legislature mandated a 20 percent decrease in greenhouse gas emissions by 2035 through the reduction of average vehicle miles traveled (VMT) by the region’s cars and small trucks. The mandate created a unique opportunity for the Oregon Health Authority and Metro—the regional government serving the Portland metropolitan area—to look at the intersection of land use, transportation, and health.

From a transportation standpoint, reducing VMT could help reduce greenhouse gas emissions, time spent in traffic, and travel costs on the region’s roadways. From a public health perspective, lowering VMT could improve health by reducing pollution, improving traffic safety, and increasing walking and biking.

Staff in the Health Impact Assessment Program, a part of the Oregon Health Authority’s Public Health Division, conducted three health impact assessments to examine a range of potential transportation and land use strategies, and investment scenarios. These health impact assessments would help inform a series of decisions within Metro's community planning process. Health Impact Assessment Program staff relied on expertise from members of Metro’s technical advisory committees, local planning, public health and environmental justice nonprofits.

“This collaborative approach is a win-win because it allows us to identify and propose evidence-based solutions that help both people and the environment,” said Andrea Hamberg, Program Coordinator for the Health Impact Assessment Program at the Oregon Health Authority.

To quantify how increases in miles traveled by walking and biking combined with a decrease in per capita VMT would impact health, the agencies adapted a tool called the Integrated Transport and Health Impact Model (ITHIM) for their health impact assessments. Originally developed at the University of Cambridge School of Clinical Medicine, this comparative assessment tool has only been used by one other group in the United States.

The goal is to take a “burden of disease” approach to regional, state, and local data and decision-making, using the ITHIM modeling tool to project future health outcomes from complex data sets. To do this, ITHIM synthesizes data from sources such as the Oregon vital statistics records, peer-reviewed literature for the likelihood of health impacts, regional household travel surveys, regional air quality monitoring and modeling, and Oregon traffic fatality and severe injury crashes. The results were striking.

“The output data from ITHIM found that strategies and investments considered in Metro’s planning could increase physical activity among residents, improve air quality, and reduce traffic injuries and fatalities,” said Hamberg.

Even modest increases of active transportation could translate into impressive health gains across the region. “By increasing the average distance walked from 1.3 to 1.8 miles per week, ITHIM shows that 48 premature deaths can be avoided annually,” said Hamberg. “Additionally, 13 premature deaths will be avoided if miles traveled per person per week by bicycle increase from 2.1 to 3.6.”

Monetizing the health benefits associated with decreased illness and death to influence decision-making was another crucial component to Metro’s scenario planning. “We estimate that the region currently spends about $4.8 and $5.8 billion each year on the diseases modeled in ITHIM,” said Nicole Iroz-Elardo, Policy Analyst for the Health Impact Assessment Program at the Oregon Health Authority. The draft strategy developed by Metro analyzed with ITHIM is projected to reduce illness and save the region $100–$125 million annually. “This includes annual savings of nearly $64 million in expenditures and lost productivity related to cardiovascular disease, $35 million associated with traffic injuries, and $26 million related to diabetes treatment.”

In December 2014, Metro is expected to make a final decision on the adoption of a Climate Smart Strategy. “Our goal is to support policymakers with objective information to aid decision-making,” said Hamberg. “These tools have helped us quantify the case for health.”