Planning October 2014
Bridging to Public Health
Using scenario planning in broader ways.
By Lawrence Frank and Jared Ulmer, AICP
Generally speaking, most planners understand the connections between transportation, land use, and health. But the nature and extent of specific health impacts remain hard to gauge.
There is plenty of evidence: Two recent studies, one in Charlotte, North Carolina, and the other in Los Angeles, documented that transit investments actually resulted in an increase in walking. Other causal studies have documented that changes in the built environment result in changes in walking and healthy body weight.
Hundreds of other studies connect the built environment or aspects of "walkability" with active transportation and healthy body weight. Many extend this connection to a range of health outcomes, including diabetes, cardiovascular disease, and traffic safety. There are direct links between community design and sedentary behavior, and between time spent sitting in cars and health impacts.
But how do we apply this new evidence to on-the-ground decisions? While most politicians will argue the need for "healthy communities," relatively few have supported major shifts in funding priorities to make it happen. Most people need a compelling reason to leave their cars behind and shift to walking, biking, or transit, when driving is faster.
Quantifying the impacts
Public health and planning professionals understand the need to quantify the health impacts of alternative approaches to building communities. Yet even with emerging evidence, the methods to apply it have been limited. To date, most health impact assessments have been qualitative in nature; they have failed to quantify the relative health impacts of contrasting development proposals.
As evidence on the linkages between health and built environment mounts, urban planners are developing scenario-planning tools that help to empirically evaluate the impacts of alternative growth proposals. Likewise, health impact assessments are attracting considerable interest among public health professionals.
Scenario-planning software provides the framework to build evidence into a decision-support tool that can be readily applied at a range of geographic scales. It lets users evaluate a broad array of environmental, economic, and now health impacts of alternative approaches to development.
As with environmental impact assessments, health impact assessments seek to evaluate the impacts of laws, policies, programs, plans, or investments, but with a focus on human health. HIAs have been largely qualitative or relied on generalized empirical assumptions found in existing research. An HIA may cite a study linking sidewalks to increased physical activity as evidence for requiring a developer to provide sidewalks in a new subdivision. This approach does little more than support the intuitive notion that more sidewalks should lead to more walking.
A more direct approach to evaluating the health-related impacts of an investment could show how much walking is expected to change, ideally reported across different age, income, and gender subgroups. It could also predict downstream impacts on body weight, chronic disease, and related health care costs savings. This information is needed to create cost-benefit models that can evaluate dollars spent to dollars saved across a range of potential improvements, thus possibly strengthening arguments for expenditures on walking, biking, and transit facilities. Evidence-based, scenario planning can accomplish this.
By incorporating health into the scenario-planning process, planners would have a readily usable quantitative health impact assessment tool. Scenario-planning tools apply statistical relationships to real-world physical design alternatives between built environment features and a range of environmental, economic, and health-based outcomes, while controlling for demographics.
Scenario-planning tools can now provide detailed estimates of the potential impacts of different policy scenarios on a range of health outcomes. They can evaluate policy and plan-level health impacts or detailed project and infrastructure level impacts, including transit improvements, pedestrian and bike infrastructure changes, or development changes at the neighborhood scale, corridor subregional level, or even at the regional scale.
Vastly improved computing capacity, detailed transportation and GIS data, and visualization tools collectively help make scenario planning fast enough to be used as a public involvement tool. Stakeholders can examine the alternatives and their impacts "live" as part of public meetings.
Urban Design 4 Health is a consulting firm specializing in applying research evidence on the interactions between land use, transportation, air quality, climate change, and public health to real-world decisions. UD4H has worked with several organizations recently, including the Sacramento Council of Governments, King County (Washington), California's Strategic Growth Council, Southern California Association of Governments, and Toronto Public Health to incorporate health into scenario-planning software.
This work builds on a large body of well-cited publications using evidence collected in part through National Institutes of Health grants over the past decade, and has resulted in health-related impacts being evaluated through several scenario-planning software platforms.
Those platforms include INDEX, developed by Criterion Planners, CommunityViz (by Placeways LLC), and most recently UrbanFootprint (by Calthorpe Associates). Through scenario planning, estimates of health impacts are tied directly and spatially to the transportation and land-use changes being considered. Statistical model results are programmed into the software.
This approach integrates health goals into the daily business of planning. Health indicators are seen alongside other indicators, allowing planners, stakeholders, and decision makers to weigh the trade-offs of each decision and compare the performance of different design alternatives.
Tool development
Developing a scenario-planning tool with health impacts requires detailed data on travel/activity patterns (behavior), health outcomes, and demographics spatially matched with high-resolution, parcel-level built environment and transportation systems data.
Health prevalence surveys document physical activity, body weight, and the incidence of diabetes, heart disease, asthma, and depression, sometimes along with information on perceptions of the built environment, sense of community, and diet. Other data document traffic safety and crash frequency, while travel surveys provide trip frequency, distance, and travel time per mode.
These data sources include information on age, income, ethnicity, vehicle ownership, and household structure and are linked with detailed built environment factors through observation-specific road network buffers (most often about one kilometer, or 0.6 miles). Built environment features include access to parks, shops, transit, sidewalk presence, and to a set of walkability factors including net residential density, street connectivity, and site design around retail establishments.
A caveat: One of the jobs of health authorities is to guard the confidentiality of health outcome data, yet this work requires spatial specificity. Therefore, the fine geographic scale of the data requires ensuring that survey participants remain anonymous.
Once the variables are created, statistical analyses are conducted to evaluate relationships between the built environment, behavior, and health outcomes while controlling for demographics and regional accessibility (travel time) by available travel modes. It is clear that built environment relationships differ significantly across age, income, and gender. Where sample sizes are sufficient, models can be developed for specific demographic subgroups.
Results provide the basis to predict the amount of change in a given outcome (for example, walking) in response to the addition of sidewalks in a neighborhood (predictor variable). Statistical relationships are then programmed into the scenario-planning tool.
Applying the tool
Planned changes to the built environment are used as a basis to test the scenario-planning tool's functionality and validate the results it produces. Users work with this new enhanced HIA tool in essentially the same way they would with any data in the scenario-planning process: by providing detailed land-use and transportation system characteristics of potential transportation, development, or redevelopment scenarios.
Two recent California projects directly link health outcomes with built environment features. The projects (one in the San Diego region, another statewide) use an approach approved by a technical advisory committee of experts from the Rand Corporation, UCLA, UC Berkeley, the U.S. Centers for Disease Control and Prevention, the California Department of Public Health, and the San Diego County Department of Health and Human Services.
The San Diego project was funded by a CDC Prevention Communities Putting Prevention to Work grant to the San Diego County Department of Health and Human Services and the San Diego Association of Governments. The project uses CommunityViz and three data sources for outcomes:
- San Diego Association of Governments' 2006 travel survey data of 3,651 households for information on travel patterns
- California Health Interview Survey data on 18,000 participants for health outcomes over five waves
- California Statewide Integrated Traffic Reporting System for data on traffic collisions
Large sample sizes and highly detailed parcel-level built environment data made it possible to conduct separate analyses for children, teens, and adults and to test a wide range of planning-related health impacts.
A GIS-based evaluation of neighborhood characteristics for each household provides the independent variables in the analysis. Sidewalk data was collected through aerial imagery. Auditing of park features and food establishments was conducted through the NIH-funded Neighborhood Impact on Kids study.
As part of the project, these built environment variables were also mapped across the region at the block group level to create the Healthy Communities Atlas, a series of maps depicting health-related conditions.
Application of the HIA tool requires gathering data on current and "change" or "future" scenarios. Typical sources include local government, metropolitan planning organizations, and major developers. In many cases planning of future conditions is not detailed enough to provide needed inputs, but it is possible to make reasonable assumptions based on current zoning and estimated residential and employment populations.
Users of the HIA tool can modify land-use characteristics (land uses, housing types, and densities); transportation system characteristics (street connectivity, sidewalk and bike lane coverage, transit service type, and stop/route locations); and locations of schools, parks, and food outlets. These are modified by "painting" place types (groupings of different development types, quantities, and densities) across the study region, and by importing GIS shapefiles that indicate the location and features of proposed changes.
For the San Diego region, the case study area used to evaluate the tool itself was the Palomar Gateway District in Chula Vista. This older, largely suburban and residential community is evolving into one that is more compact, walkable, and focused around an existing San Diego Trolley (light-rail) station.
This case study compared current conditions to the adopted plan build-out for the Palomar Gateway District. The plan proposed land-use changes such as new infill and redevelopment housing (with an emphasis on multifamily housing) and retail uses at a more urban scale than today, and the introduction of other complementary uses including office and entertainment. In transportation, the plan anticipates improvements to the light-rail and local bus systems, as well as enhancement of pedestrian and cycling infrastructure.
The accompanying table shows the estimated health impacts of the Palomar Gateway Plan — some of them in blue (positive) and orange (negative) are substantial. For adults, the amount of walking for transportation is predicted to almost double. Body mass index, high blood pressure, and Type 2 diabetes in adults are all expected to decline. For children and teens, transportation walking and recreational physical activity are predicted to increase, while body mass index decreases.
While the predicted health impacts are generally positive, the results also indicate some concerns. The prevalence of asthma is projected to go up among children and teens, though not adults. Modeling results suggest that greater housing density near major roads will increase child and teen exposure to vehicular emissions, a result consistent with published evidence. This impact can potentially be mitigated through cleaner vehicle and fuel technologies, policies aimed at reducing traffic volume, or through landscaped buffers between major roads and adjacent housing.
We also found the risk for pedestrian and cyclist collisions with vehicles was expected to increase. This highlights the need for vehicular traffic calming and improved signalization, crosswalks, bike facilities, and other safety enhancements. These results reveal the complex interactions between the built environment and different subpopulations across a wide range of health outcomes. While a walkable urban form is an increasingly important policy priority, the development and traffic that come with it can have adverse consequences.
The scenario-planning tool provides a method to diagnose health impacts and make changes to planned actions to promote health in a proactive manner. The scenario tested was not designed with this information available. However, with additional testing, it is possible to generate a "health-optimizing scenario." Rather than starting with a particular plan and testing its impacts, this approach would start by identifying the desired quality-of-life goals, and conducting iterative testing to find a scenario that comes closest to achieving those goals.
Next steps
The method presented in the Palomar case study is now being applied statewide. This work is part of the Strategic Growth Council's UrbanFootprint tool development effort, initiated to predict carbon dioxide impacts of regional sustainable community strategies pursuant to California's SB 375, passed in 2008. UD4H is working with Calthorpe Associates to develop the health module within UrbanFootprint and is applying the results first in the Sacramento and Los Angeles regions.
This statewide effort offers promise because it increases the variation in urban settings and walkability across age and income subgroups. The Sacramento Council of Governments and the state Office of Policy Research have provided considerable leadership and oversight. UrbanFootprint was developed by Calthorpe Associates as a scenario-planning software platform to address many previous limitations, adding an improved user interface and cloud computing.
It should come as little surprise that not all major transportation agencies embrace research showing that more roads could undermine public health. Evidence and the ability to apply it directly to real-world decisions in a visually compelling manner are essential to fostering the momentum needed for improved public health.
Finally, a word from William Anderson, FAICP, principal and vice president of AECOM (and the president of APA): "Awareness about the link between development form and public health is growing rapidly," Anderson says. "As this movement develops, [it's good to be reminded] of the importance of grounded analysis using the sophisticated modeling tools and databases available."
Lawrence Frank is president of Urban Design 4 Health, Inc. and a professor of community and regional planning and population and public health at the University of British Columbia in Vancouver. Jared Ulmer is a senior planner and analyst at UD4H. Jim Chapman, Sarah Kavage, and Eric Fox also contributed to this story. Miguel Tapia, AICP, of the Chula Vista, California, Development Services Department provided information on the Palomar Gateway District.
| Can Trees Save Your Life? |
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By Rachel White A tiny, metallic-green forest pest laid the groundwork. Known as the emerald ash borer, this invasive insect has recently killed huge numbers of trees across 15 Midwestern states, making possible a unique study into man's affinity to nature. Geoffrey Donovan, a researcher with the U.S. Forest Service, started with the hypothesis that trees improve people's health. "If that's true, then killing 100 million trees in 10 years should have a measurable effect," he says. "Because it spreads quickly, the emerald ash borer provides a rare opportunity to quantify the human health impacts of widespread tree mortality." The insect attacks all 22 species of North American ash and kills nearly every tree it infests. Fort Wayne, Indiana, has seen this devastation. Emerald ash borers showed up there in 2006, says Chad Tinkel, manager of forestry operations for Fort Wayne Parks and Recreation. "Before the emerald ash borer hit, we had 14,000 ash trees," he says. "By 2008 we had thousands of standing dead trees, and neighborhoods were just bare."
Donovan's results, published in 2013 in the American Journal of Preventive Medicine, suggest that these tree deaths had serious public health consequences. Infested counties were associated with increased human mortality — more than 21,000 human deaths beyond the expected number (after taking account of other factors like education, income, and race). Some 6,113 deaths were related to lower respiratory illnesses, another 15,080 to cardiovascular problems. These types of death are the first and third most common in the U.S. Does the distress of deforestation push fragile people to the breaking point? Or is a decline in air quality a decisive factor? Either factor could explain the increase in human mortality. But what matters is simply knowing there's a link. Trees are an aspect of the natural environment we can change. And as we are learning, trees are part of a city's public health infrastructure — an effective argument for allocating resources to the protection and expansion of urban forests. "This study is about the positive things that trees can do for people," says Donovan. "You don't always understand what trees give us until you take them away." Rachel White is a science writer with the USDA Forest Service. Image: The emerald ash borer, an invasive Asian beetle that feeds on and kills ash trees, was first discovered in the U.S. in 2002 near Detroit, Michigan. To date, it has spread to 24 U.S. states and two Canadian provinces and caused tens of millions of dollars in damage. Photo by Minnesota Department of Natural Resources via the New York Times. |
| Lessons from Comprehensive Health Planning |
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By Lucie Vogel, AICP For 40 years, federally supported comprehensive health planning at local, state, and federal levels was standard. Although it was eliminated in the 1980s, the principles and practices of comprehensive health planning — an initiative managed by the U.S. Department of Health and Human Services — still provide lessons for the efforts of planning and public health agencies to address health issues. The Hill-Burton Act of 1946 was the first in a series of laws that resulted in a collaborative planning effort for improved health, but comprehensive health planning faded in 1986. Those planning efforts depended on intergovernmental cooperation and public-private partnerships — including philanthropy, medical associations, industry, labor, medical facilities, doctors and other providers, and community residents — to fund local, state, and regional agencies. That model holds. While both government and market conditions have changed, solutions to major health policy issues such as those embodied in the Affordable Care Act still rest on a policy of public-private partnership with insurance, health care providers, and governments. Today, programs are also linked to transportation and education. Partnerships underpin implementation of plans and programs addressing health and social issues. Engage stakeholders Comprehensive health planning agencies have always used innovative techniques to engage diverse stakeholders. Examples include the nominal group technique for public hearings first implemented for the Wisconsin Health Plan and the Delphi survey used to poll administrators on organizational issues for medical centers by the Association of Academic Health Centers. These facilitation tools and newer methods, such as using electronic technology for input and keypad voting, are essential for developing any community, regional, or state plan. Other examples include electronic wellness surveys for needs assessment, scenario building workshops to visualize alternatives, and coalition-building efforts with a range of participation options at the community and state levels. Include a broad concept of health The 1946 World Health Organization definition of health as "complete physical, mental and social well–being" provided a broad foundation for considering community and social factors that contribute to health. Healthy People, an HHS program begun in 1979, echoed that view and continues to drive federal and state efforts to plan for public health. The ACA furthers that big-picture approach to health, providing parity for mental health and including public health and prevention services. Analyze with reliable data The comprehensive health planning of the past depended on the intensive use of data for formal needs assessment. These included historical analogies, trend extrapolation, decision theory, surveys, computer simulation, and epidemiological approaches. Maps identified the location of manpower and the distance to care. That mapping and analysis revealed key regional and demographic differences, which helped to create a new field that studied health disparities. Today there are many more types of data: electronic diagnostic codes from billing information, electronic health records, and GIS information from social media. Further, there is a growing emphasis on evidence-based research and health outcomes to identify which community and service efforts will improve chronic health conditions. Implement with carrots and sticks Health planning traditionally depended on the combination of regulation and incentives: requiring certificates of need for new facilities and providing construction funds for approved projects. Likewise, government administrative rules and market incentives helped reduce both tobacco use and motor vehicle deaths. The Affordable Care Act continues this carrot-and-sticks approach, with requirements and funding that expand access and insurance coverage. Without the leadership of formal health planning agencies, planning must strive to include health issues and resources — by working across professions, markets, and governments. Broadening the scope of health and focusing on the social determinants means providing behavioral health screening with primary care and identifying links to the built environment through safe streets, opportunities for fitness, and access to healthy foods. The reemergence of joint efforts between planning and public health agencies such as the Centers for Disease Control and Prevention's Healthy Community Design Toolkit and the health in transportation working group of the Federal Highway Administration is an encouraging trend in the development of comprehensive health improvement planning. Lucie Vogel is a planner who has worked on health planning for state government, a university medical center, a professional association, and the federal government. |