You’re already practicing public health
The civil engineer who specifies a twelve-foot lane instead of a ten. The architect who orients a mixed-use building toward the parking lot rather than the sidewalk. The developer who builds eighty garden apartments wrapped around surface parking— but no playground or public spaces. The planner who rezones a historic neighborhood for single-family detached only. Each of these practitioners is making a public health decision— whether or not it appeared in the project scope, whether or not they trained for it, whether or not they would describe their work that way at a dinner party or on their CV.
This is not an appeal for the design and development professions to begin considering public health. The decisions are already happening. The only question is whether we accept the responsibility consciously or impose it on others unconsciously.
I come to this argument from inside two professions that rarely speak to each other. I am a Clinical Nurse Leader within a federal health system, a DrPH student at the Johns Hopkins Bloomberg School of Public Health, the founder of a small infrastructure advisory firm, and the co-founder of a regional greenway nonprofit in Pensacola, Florida. I am also a father of seven, and like everyone else’s children, the health of my children is being shaped every day by people who do not think of themselves as practicing medicine. That translation problem is what this essay is about.
More than twenty years of evidence have settled the underlying claim. Urban Sprawl and Public Health, edited by Drs. Howard Frumkin, Lawrence Frank, and Richard Jackson, established the foundation in 2004; the literature since has only grown stronger and more specific. Frumkin himself—former director of the CDC’s National Center for Environmental Health and dean emeritus at the University of Washington School of Public Health—puts the conclusion as plainly as a former federal health official can: “the design of our communities … is one of the most powerful determinants of health.” Not a determinant. One of the most powerful.
What that means in practice is more concrete than the public health literature usually makes it sound. Lane width determines pedestrian death rates. Sidewalk presence determines how much (or whether) a child walks. Block length and intersection density determine cardiovascular risk in adults. Parking minimums determine the air quality children breathe on their way to school. Building setbacks and street tree canopies determine heat morbidity in elderly residents during the increasingly long summers we are now engineering for them. Mixed-use entitlements determine whether an eighty-year-old who no longer drives can reach a pharmacy without becoming a shut-in. Each is a routine decision, made every day, by professionals who would not say they are working in health. Each is a health decision regardless.
Shima Hamidi, the Bloomberg Assistant Professor of American Health at Johns Hopkins and director of its Center for Climate-Smart Transportation, has spent her career quantifying these relationships. Her sprawl indices, developed with Reid Ewing, are now the standard tool for measuring how development patterns translate into mortality, morbidity, and healthcare costs. Her widely covered 2020 work on density and COVID-19 made the necessary distinction between density and crowding, and her more recent research on lane width has shown that twelve-foot urban lanes produce roughly fifty percent more crashes than nine or ten-foot ones. Her summary of the evidence is as direct as Frumkin’s: “urban planners should continue to advocate for compact places rather than sprawling ones.” That sentence is not a planning opinion. It is a clinical recommendation.
The retreat into specialty silos does not work as a defense. The traffic engineer who widens a residential street to “improve flow” has just increased pedestrian fatalities, even if the design intent was traffic operations. The developer who builds car-dependent garden apartments has engineered diabetes risk into the daily routine of every future resident. The planner who writes parking minimums has prescribed a level of automobile dependence and air-pollution exposure for an entire neighborhood, in the same way a prescriber writes a long-term medication. The decisions are being made; the only thing in question is whether they are being made well.
There is a deep historical irony in our current condition. Zoning was originally a public health instrument. The 1916 New York Zoning Resolution mandated setbacks so that sunlight could reach the streets and tenements would no longer breed tuberculosis. The earliest American comprehensive zoning emerged from decades of housing reform that had given health boards authority to regulate ventilation, light, and sanitation. The point of the work, in its founding generation, was to prevent the sickness of the poor. Mid-century, the tool drifted from its original mission and was repurposed to separate neighbors rather than nuisances, to defend property values and exclude rather than to protect public health. The modern low-density, single-use, parking-saturated American development pattern is the long-run product of that drift. It produces health outcomes opposite to those zoning was created to deliver: obesity from forced inactivity, respiratory disease from auto emissions, traffic deaths from compulsory driving, and the social isolation that shows up downstream as depression and dementia.
The Charter for the New Urbanism, adopted in 1996, is in part a recovery of zoning’s original public health function—updated with twenty-first-century evidence about what actually creates healthy places. Principle 12 is, read carefully, a behavioral health prescription: “Many activities of daily living should occur within walking distance, allowing independence to those who do not drive, especially the elderly and the young.” That is a sentence about morbidity and mortality at the end of life. When we design a neighborhood in which a great-grandmother who has stopped driving cannot reach her parish, her grocery store, or her grandchildren on foot, we have made a decision about how she will spend her remaining years. Principle 23 is the same kind of sentence applied to the public realm: “Streets and squares should be safe, comfortable, and interesting to the pedestrian. Properly configured, they encourage walking and enable neighbors to know each other and protect their communities.” The verb that does the work in that sentence is encourage. Design encourages behavior; behavior produces health outcomes; designers are therefore practicing behavioral health, whether that vocabulary is theirs or not.
Some readers will reasonably object that practitioners are not free agents. We work inside zoning codes we did not write, capital stacks we did not structure, market expectations we did not invent, and client demands that frequently push in the wrong direction. That is true, and I want to honor it. But naming the public health stakes changes what we fight for inside those constraints. The developer who understands that a surface parking lot is, among other things, a heat island that will kill some number of nearby elderly residents during the next extreme weather event will fight harder for structured parking, deeper canopy, or—better—fewer cars. The engineer who has internalized the Strong Towns observation that the design speed of a road is more than “engineering judgment” but a matter of life and death will push for ten-foot lanes against a manual that prefers twelve. The planner who recognizes that parking minimums are an indirect prescription for cardiovascular disease will work to eliminate them rather than soften them. None of this requires anyone to retrain as an epidemiologist. It requires only that we stop pretending the decisions are about something else.
The gap between the evidence and the practice is institutional, not scientific. Architecture schools rarely teach building design as health intervention. Civil engineering programs optimize for traffic flow without quantifying the resulting body count. Real estate development curricula model financial pro formas without a parallel column for downstream healthcare costs. Planning programs treat health as a separate concern rather than the consequence of every land-use decision. Professional licensure exams test almost none of this. The ignorance is structural, but ignorance has never been a defense against the consequences of professional action.
What the field needs now is not more research. The research is settled, and Frumkin, Hamidi, and a generation of others have done the work. What the field needs is professional courage—the willingness of designers, engineers, developers, and planners to claim public health as their own work, and to accept the responsibility that comes with the claim. The most useful thing any of us can do tomorrow is name it, out loud, in rooms where decisions are being made. Say in a design review that this lane width will increase pedestrian deaths. Say at the planning commission that these parking minimums will worsen the air quality in the schools downwind. Say in the underwriting memo that this site plan will reduce residents’ physical activity over the life of the lease. Once a thing is named, it can be designed for. Until it is named, it will continue to be designed against, by default, every day.
Places shape persons. The streets, blocks, and buildings we are drawing right now will determine how long our neighbors live, how well they live, and what eventually kills them. That is the practice. The only question is whether we are willing to call it by its proper name.
