If you want to know whether a city is truly working, don’t start by asking the happiest commuters or the residents with the most options. Start with the people the city fails first: those with the least money, the least power, the least time, the least safety, and the fewest ways to “just make it work.” Design a city for them, and you don’t just build a kinder place—you build a city that functions better for everyone.

This is the logic behind a simple test: if it works for elders and young children, it works for everyone. The same holds—often even more urgently—for people with disabilities, people experiencing homelessness, migrants and refugees, low-wage workers, single parents, and communities historically pushed to the edges. Marginalization isn’t a niche issue. It’s a stress test. And our cities are failing it.

Consider what daily life looks like when you’re living on the thinnest margin. A missed bus isn’t an inconvenience—it’s a lost shift and a smaller paycheck. A poorly lit street isn’t “a little sketchy”—it’s a route you avoid, even if it adds an hour to your commute. A lack of public toilets isn’t an annoyance—it’s a health risk, an indignity, a reason to stay home. When sidewalks are broken, when crossings are too long, when ramps are missing, when services are scattered and confusing, the cost is paid in time, injury, money, and fear. That cost is concentrated on the people who can least afford it.

Meanwhile, the solutions that support the most marginalized are rarely exotic. They are practical, ordinary, and overdue: safe sidewalks and protected crossings. Frequent, reliable public transit that runs early, late, and everywhere—not just where it’s profitable. Housing that is genuinely affordable, stable, and close to jobs and schools. Public restrooms. Shade and benches. Streetlights that work. Community health clinics within reach. Schools and childcare that don’t require a second job’s worth of logistics. A city that can be navigated without a car, without constant vigilance, without a smartphone battery that never dies.

These changes sound small until you count what they return. When you build a neighborhood where a child can walk to school safely, you’ve built a neighborhood where an elder can walk to the pharmacy without risking a fall or a speeding car. When you make transit legible and frequent enough for a low-wage worker to depend on, you’ve made it easier for everyone to leave the car at home. When you ensure sidewalks are accessible for wheelchair users, you’ve improved life for parents pushing strollers, people hauling groceries, delivery workers, travelers pulling luggage, and anyone nursing an injury. Universal design isn’t charity. It’s competence.

The moral case is obvious: people deserve dignity. But even if your heart doesn’t move, the math should. Cities that ignore marginalization spend more on crisis than care—more on emergency rooms than clinics, more on policing than prevention, more on temporary shelters than permanent housing. We build systems that “save” money by withholding basics, then pay a premium when predictably, preventably, people fall through the cracks. The costs don’t disappear; they compound.

There’s also a democracy argument here. A city designed for the most privileged treats everyone else as an afterthought. That’s not just unfair—it’s unstable. When residents feel the city is not for them, trust erodes. People disengage, or they lash out, or they leave if they can. Social fabric frays when public space sends an unspoken message: you don’t belong. Designing for the marginalized is a way of saying: this city is yours, too. Belonging is infrastructure.

And let’s be honest about what “marginalized” often means in practice: people who are asked to be invisible.