In the late 1940s, Robert Moses — Parks Commissioner, Construction Coordinator, and the unelected master builder of New York — decided that a new expressway must cross the South Bronx. The Cross Bronx Expressway, Moses decreed, would cut through the borough in a straight line from the George Washington Bridge to the Throgs Neck Bridge, threading through one of the most densely inhabited urban landscapes in America. Engineers identified a route that would have required relocating far fewer families — a slight adjustment of a few blocks — but Moses rejected it. He wanted his straight line.
What followed was one of the most consequential acts of urban destruction in American history. The expressway's construction between 1948 and 1963 displaced approximately 60,000 residents from the East Tremont neighborhood and a dozen other Bronx communities. In Robert Caro's landmark biography 'The Power Broker' (1974), the story is told in granular, devastating detail: the residents who received eviction notices with thirty days to find new homes in a city whose affordable housing stock was already exhausted; the elderly and the sick who had lived in the same apartments for decades; the community networks, social clubs, and small businesses that dissolved when their populations were scattered. Moses, Caro documents, was informed of the human cost in detail and was unmoved. The people of East Tremont were, in his estimation, the kind of people who did not matter.
The Cross Bronx Expressway did not merely displace 60,000 people. It cut arterial roads, drained businesses, and accelerated the abandonment of the surrounding neighborhoods. The South Bronx became a byword for urban catastrophe through the 1970s and 1980s — burned-out buildings, collapsed services, concentrated poverty. The expressway did not cause all of this, but it broke the connective tissue of neighborhoods that might otherwise have weathered other pressures. Historians and planners still debate the precise causal weight, but few dispute that Moses's decisions were among the most destructive acts of postwar urban policy.
Meanwhile, across the East River in Greenwich Village, a journalist named Jane Jacobs was watching what urban renewal was doing to her own neighborhood and organizing resistance. When Moses proposed to drive a roadway through Washington Square Park, Jacobs helped lead the coalition that stopped him. Her experience observing urban life — the sidewalk ballet of Hudson Street, the eyes on the street, the subtle ecology of a healthy neighborhood — was coalescing into a book that would challenge everything Moses represented about how cities should work.
"Cities have the capability of providing something for everybody, only because, and only when, they are created by everybody." — Jane Jacobs, The Death and Life of Great American Cities (1961)
Key Definitions
Urban planning — The professional and governmental practice of shaping how land in cities and metropolitan areas is used, developed, and connected. Urban planners regulate land use, guide infrastructure investment, coordinate transportation systems, and manage urban growth over time.
Zoning — A system of land-use regulation that divides a jurisdiction into zones specifying what types of buildings and activities are permitted in each area. Zoning codes typically specify land use categories (residential, commercial, industrial), density limits, setback requirements, minimum lot sizes, height limits, and parking requirements.
Euclidean zoning — The dominant American model of zoning, named for Euclid v. Ambler Realty (1926), in which the Supreme Court upheld the constitutionality of single-use zoning. Euclidean zoning separates housing, commerce, and industry into distinct zones and prohibits mixing of uses.
Urban renewal — Mid-twentieth-century federal policy (primarily 1949-1974) that directed federal funds to cities for the demolition of "blighted" neighborhoods and their replacement with new development, often highways and modernist housing projects. Critics argue urban renewal was used to displace poor and minority communities under the guise of improvement.
Transit-oriented development (TOD) — An approach to urban development that concentrates higher-density, mixed-use building within walking distance (typically a quarter to half mile) of transit stations, to maximize ridership and create walkable neighborhoods.
Gentrification — The process by which higher-income residents move into lower-income urban neighborhoods, raising property values, rents, and the socioeconomic character of the area. Associated with displacement of existing lower-income residents and changes to neighborhood culture.
Urban heat island — The phenomenon by which cities are significantly warmer than surrounding rural areas due to the replacement of vegetation with heat-absorbing built surfaces, waste heat from human activity, and reduced evapotranspiration. Urban heat islands amplify heat waves and disproportionately harm vulnerable residents.
15-minute city — An urban planning concept, popularized by Paris under Mayor Anne Hidalgo, in which residents can meet most daily needs — work, shopping, school, parks, healthcare — within a fifteen-minute walk or bike ride of their home, reducing car dependence and improving quality of life.
YIMBY / NIMBY — Yes In My Back Yard / Not In My Back Yard. NIMBY describes residents who oppose new development (especially housing) in their neighborhoods. YIMBY is a pro-housing counter-movement arguing that adding new housing supply is necessary to reduce housing costs.
Eminent domain — The legal power of government to take private property for public use, with compensation to the owner. Urban renewal frequently used eminent domain to assemble land for highway construction and redevelopment projects.
The History of Urban Planning
Haussmann's Paris and the Origins of Modern Planning
Modern urban planning as a governmental practice has multiple origin stories, but the transformation of Paris under Baron Georges-Eugène Haussmann between 1853 and 1870 is among the most studied. Emperor Napoleon III commissioned Haussmann to modernize Paris, and Haussmann responded with a comprehensive program of demolition and reconstruction that replaced much of medieval Paris with the wide boulevards, uniform apartment facades, and grand public spaces that define the city today.
Haussmann's interventions served multiple purposes: improving circulation, reducing cholera risk by creating modern sewers and water supply, providing employment, and — not incidentally — making it harder for revolutionary crowds to barricade the narrow medieval streets that had been the terrain of multiple uprisings. Critics then and since have noted the mass displacement of working-class Parisians from the central city to peripheral areas as a consistent effect of Haussmann's work. The formal vocabulary was aesthetic and hygienic; the political economy was the displacement of the poor.
Frederick Law Olmsted, designing Central Park in New York (1858) and a series of American parks and park systems through the late nineteenth century, represented a different strand of planning thought: the idea that urban environments could and should include large-scale naturalistic spaces for the health and recreation of urban populations. Olmsted believed that exposure to designed natural landscapes provided psychological and physical restoration unavailable in the industrial city. His parks were simultaneously amenities, engineering infrastructure (managing stormwater, mitigating heat), and social mixing spaces where different classes might encounter each other.
The City Beautiful Movement and Its Discontents
The City Beautiful movement, crystallized at the 1893 Chicago World's Columbian Exposition, argued that magnificent public architecture and urban design could uplift civic life and encourage civic virtue. Daniel Burnham's 1909 Plan of Chicago — "Make no little plans; they have no magic to stir men's blood" — proposed grand diagonal boulevards, lakefront parks, and monumental civic buildings. City Beautiful proposals were built in Washington, Cleveland, San Francisco, and Manila, providing a vision of the modern city as an ordered, beautiful whole rather than a chaotic commercial scramble.
City Beautiful was criticized for prioritizing aesthetics over the conditions of working-class life, and for a visual vocabulary that drew on European imperial grandeur rather than democratic reality. Its successor movement, City Practical or City Scientific, emphasized efficiency, infrastructure, and the separation of incompatible land uses — a tendency that would culminate in the zoning movement.
Le Corbusier and the Towers in the Park
No figure more completely embodied the twentieth century's technocratic approach to urban form than the Swiss-French architect Charles-Edouard Jeanneret, known as Le Corbusier. His "Radiant City" vision proposed demolishing large swaths of existing cities and replacing them with towers set in open parkland, connected by elevated highways, with functions strictly segregated: work here, residence there, commerce elsewhere. The existing dense street fabric of the traditional city was, to Le Corbusier, a slum of darkness, inefficiency, and disease. The tower in the park offered light, air, and rational order.
Le Corbusier's ideas were deeply influential on the federally funded public housing programs built in American cities from the 1940s through the 1970s. The results were, in many cases, catastrophic. Cabrini-Green in Chicago, Pruitt-Igoe in St. Louis, and the Robert Taylor Homes — enormous towers set in superblocks with no ground-floor uses, no corner stores, no variety of activity — became symbols of social failure. The ground-level surveillance and community activity that Jane Jacobs identified as essential to neighborhood safety were deliberately eliminated by the tower-in-park design. Pruitt-Igoe was demolished just sixteen years after it opened.
Jane Jacobs and the Urban Vitality Framework
Jane Jacobs's 'The Death and Life of Great American Cities' (1961) is one of the few planning books that changed how planners think and also changed how ordinary people talk about cities. Written by a journalist with no formal planning credentials, it was rejected by many professionals at the time of publication and is now widely regarded as the most important urban planning text of the twentieth century.
Jacobs's method was empirical and observational rather than abstract. She watched Hudson Street, where she lived in Greenwich Village. She watched how the sidewalk worked — who was out at what hours, what kept the street safe, what generated the activity that made it pleasant to walk on. She compared successful urban streets to failed urban environments and asked what the difference was.
Her conclusion was that vital urban neighborhoods share four generative conditions. First, mixed primary uses: when offices, residences, and entertainment are intermixed, streets are active at different times of day and evening — workers leave their offices as residents return home, restaurants and bars serve both. Neighborhoods with only residential use are dead for much of the day; those with only offices are dead on evenings and weekends. Second, short blocks: when blocks are short, pedestrians can choose among many routes, increasing the frequency of pedestrian traffic on any given street and the number of street corners where different flows of people mix. Third, buildings of varying age: new, expensive buildings can only be afforded by enterprises with high revenues. Old, cheap buildings house the marginal, the experimental, the new — the jazz clubs, the immigrant businesses, the political organizations that cannot afford new rents. Neighborhoods without old buildings lose this creative layer. Fourth, sufficient density: enough people must be present to support local commerce and generate the informal social contact that makes a neighborhood feel inhabited.
Jacobs also developed the concept of "eyes on the street" — the informal surveillance of public space by residents and shopkeepers going about their daily lives. Safe streets are not policed streets; they are watched streets. Ground-floor uses that generate activity, windows that face the sidewalk, residents with attachment to their neighborhood — these produce the natural surveillance that makes a street feel secure. The tower in the park, by removing ground-floor uses and concentrating all entry and exit at a few lobby points, destroyed this surveillance structure.
Jacobs versus Le Corbusier as Competing Urban Philosophies
The contrast between Jacobs and Le Corbusier is more than a disagreement about design; it is a disagreement about what cities are for and how knowledge about cities can be acquired. Le Corbusier approached the city as an engineer approaches a machine: identify the functions to be performed, optimize each separately, arrange them in a rational order. The city as a whole can be planned top-down by experts who understand the principles of efficient urban form.
Jacobs approached the city as a complex adaptive system: emergent, self-organizing, generating order through the interactions of many agents pursuing many purposes. The knowledge required to design a city well is not available to any central planner, because it is distributed through the daily practices and adaptations of millions of residents, shopkeepers, and workers. An urban plan that imposes order by eliminating this diversity eliminates the very processes that generate urban vitality.
This distinction between planned order and spontaneous order has ramifications well beyond urban design, echoing debates in economics, political theory, and systems thinking. In the urban context, it suggests that the planner's proper role is not to design urban outcomes but to establish the conditions — the rules, the infrastructure, the legal framework — within which diverse, adaptive urban activity can flourish.
Zoning, Housing Scarcity, and the Affordability Crisis
The Origins and Structure of Zoning
Zoning as a comprehensive system of land-use regulation emerged in American cities in the early twentieth century. New York City adopted the first comprehensive zoning ordinance in 1916. The legal foundation was established by the Supreme Court in Village of Euclid v. Ambler Realty (1926), which upheld the constitutionality of single-use zoning against a challenge from a developer arguing that the regulation amounted to an unconstitutional taking of property value.
Euclidean zoning's separation of residential, commercial, and industrial uses had a genuine public health rationale in the industrial era: keeping slaughterhouses, tanneries, and steel mills out of residential neighborhoods protected residents from genuine pollution hazards. As pollution controls improved and light industrial activity shifted to the suburbs, the health rationale eroded. But the institutional machinery of single-use zoning remained and expanded.
The modern American zoning code is an extraordinarily complex document specifying permitted uses, density limits, minimum lot sizes, setbacks, floor-area ratios, building heights, parking requirements, and sometimes facade materials and design standards. In many high-demand cities, zoning effectively prohibits apartment buildings on a large majority of residential land — limiting new construction to expensive single-family homes on large lots.
Zoning and Housing Costs
The connection between restrictive zoning and high housing costs is well-established in urban economics. When zoning prevents new housing supply from responding to increased demand — when more people want to live in a city than there are homes available — prices rise. This is not a controversial claim; it is basic supply and demand applied to a market subject to regulatory supply constraints.
Economist Edward Glaeser, in 'Triumph of the City' (2011), argued that the failure to build dense housing in high-productivity cities represents one of the most economically costly policy failures in the modern economy. High-productivity cities generate large agglomeration benefits — workers are more productive, innovations happen faster, businesses find customers and suppliers more easily — when more people can access them. Restrictive zoning prevents workers from moving to where they would be most productive, reducing both individual income and aggregate economic growth. Economists Chang-Tai Hsieh and Enrico Moretti estimated in 2019 that lowering land-use regulations in New York, San Francisco, and San Jose to the median American level would increase US GDP by approximately 2% — roughly $400 billion annually.
The YIMBY (Yes In My Back Yard) movement, which emerged in cities like San Francisco, London, and Auckland in the 2010s, argues that the primary solution to the housing affordability crisis is to change zoning laws to allow more housing to be built. YIMBY activists have achieved notable victories: Oregon and California have both passed legislation overriding local single-family zoning, and New Zealand ended single-family-only zoning nationally in 2021. The empirical evidence on the effects of these reforms is accumulating; early results suggest that allowing more supply does reduce rents, particularly in the broader market rather than the specific neighborhoods where new construction appears.
Displacement, Gentrification, and Who Bears the Costs
The housing affordability debate intersects with the politics of gentrification and displacement in ways that are politically contentious and empirically complex. Opponents of new housing development in existing neighborhoods often argue that new market-rate construction accelerates gentrification and displaces lower-income residents. YIMBY advocates argue that restricting new supply worsens affordability overall and that the failure to build is itself a cause of displacement.
The academic evidence on displacement from gentrification is genuinely mixed. Lance Freeman's widely cited 2005 study of displacement in American cities found that displacement of low-income renters from gentrifying neighborhoods was smaller than commonly assumed, because most residents stayed in their neighborhoods even as rents rose — exit rates from gentrifying neighborhoods were not much higher than from comparable non-gentrifying neighborhoods. Freeman's work was influential in complicating the displacement narrative.
Subsequent research has refined and in many cases pushed back on Freeman's findings. Studies using more precise methods and more recent data have found larger displacement effects, particularly for households on fixed incomes, households with children in school, and neighborhoods experiencing the most rapid price increases. There is also the question of exclusionary displacement — households who would have moved into a neighborhood but are priced out by rising rents before they arrive, a form of displacement that does not appear in studies tracking existing residents.
The broader political economy question is not whether gentrification causes displacement — in at least some cases it does — but whether the alternative to gentrification in many neighborhoods is sustained investment and improvement or continued disinvestment and abandonment. Cities that have maintained affordable housing through rent control and community land trusts while also permitting new supply appear to do better on both dimensions than those that pursue either policy in isolation.
Urban Planning and Climate
Urban Heat Islands and Green Infrastructure
Urban areas are significantly warmer than surrounding rural areas — typically 1 to 3 degrees Celsius warmer, and up to 7 to 10 degrees on clear summer nights. This urban heat island effect results from the replacement of vegetation and permeable surfaces with heat-absorbing concrete, asphalt, and roofing materials; the reduction in evapotranspiration (the cooling effect of vegetation releasing water vapor); and waste heat from vehicles, air conditioners, and industrial processes.
Heat islands are not merely uncomfortable: they kill people. During the 2003 European heat wave, approximately 70,000 excess deaths occurred across the continent, concentrated in dense urban areas where nighttime temperatures offered no relief from daytime heat. The victims were disproportionately elderly, poor, and isolated — those without air conditioning, without social networks to check on them, and without resources to leave the city.
Green infrastructure — urban tree canopy, green roofs, parks, permeable paving, urban wetlands — reduces heat island intensity, manages stormwater, improves air quality, and provides mental health benefits. Cities have increasingly incorporated green infrastructure into their planning frameworks, though the distribution of urban greenery remains deeply unequal: wealthier neighborhoods consistently have more tree canopy and park access than poorer ones.
The 15-Minute City and Sustainable Urban Form
The 15-minute city concept — developed by urbanist Carlos Moreno and implemented as policy by Paris Mayor Anne Hidalgo — proposes redesigning urban space so that all residents can access essential services within a fifteen-minute walk or bike ride. The policy implications include converting car-dominated street space to pedestrian and cycling infrastructure, increasing the density and mix of uses in residential neighborhoods, and investing in local rather than regional amenities.
The 15-minute city connects to broader debates about compact versus dispersed urban form and climate. Denser, mixed-use, transit-accessible urban environments have dramatically lower per-capita carbon footprints than low-density car-dependent suburbs. Residents of walkable urban neighborhoods drive less, use energy more efficiently in denser buildings, and have smaller transportation carbon footprints. Urban planning choices made today — where housing is allowed to be built, what transportation infrastructure is funded, how streets are designed — will lock in patterns of energy use and carbon emissions for decades.
Participatory Planning and Community Rights
The transformation of urban planning practice from top-down expert imposition toward participatory processes reflects both the failure of high-modernist planning and the political mobilization of communities affected by urban renewal. The destruction of communities by Moses-era highways and housing projects was not only a human tragedy; it was a political failure that generated organized resistance and ultimately changed the legal and professional frameworks within which planning operates.
Community participation requirements were built into federal urban renewal and environmental review processes after the 1960s, partly in response to the civil rights movement's critique of urban renewal as "Negro removal" — a judgment supported by the demographic data showing that a disproportionate share of those displaced by urban renewal were African American. Environmental impact assessment requirements, adopted at the federal level in 1970, created new legal opportunities for communities to contest development projects.
Eminent domain remains a contested power. The Supreme Court's decision in Kelo v. City of New London (2005) upheld a city's use of eminent domain to transfer property from private homeowners to a private developer for economic development purposes, triggering a nationwide backlash and state-level legislation restricting the use of eminent domain for economic development.
Robert Putnam's work on social capital — the networks of trust, norms, and reciprocity that enable collective action — provides a theoretical framework for understanding why neighborhood design matters for more than housing. Neighborhoods with high social capital, where residents know each other and have collective efficacy, have better health outcomes, lower crime rates, and greater political voice than equally poor neighborhoods with low social capital. The destruction of established neighborhoods by urban renewal destroyed not just housing but social capital accumulated over generations — a cost that never appeared in planners' calculations.
For further reading on the relationship between cities, inequality, and health, see /explainers/how-it-works/how-inequality-affects-health. For the economics of urban density and productivity, see /explainers/how-it-works/why-cities-get-more-productive. For the colonial dimensions of urban planning in the Global South, see /culture/global-cross-cultural/what-is-colonialism.
References
- Caro, Robert A. The Power Broker: Robert Moses and the Fall of New York. Vintage Books, 1974.
- Jacobs, Jane. The Death and Life of Great American Cities. Random House, 1961.
- Glaeser, Edward. Triumph of the City: How Our Greatest Invention Makes Us Richer, Smarter, Greener, Healthier, and Happier. Penguin Press, 2011.
- Village of Euclid v. Ambler Realty Co., 272 U.S. 365 (1926). United States Supreme Court.
- Freeman, Lance. "Displacement or Succession? Residential Mobility in Gentrifying Neighborhoods." Urban Affairs Review 40, no. 4 (2005): 463-491. https://doi.org/10.1177/1078087404273341
- Hsieh, Chang-Tai, and Enrico Moretti. "Housing Constraints and Spatial Misallocation." American Economic Journal: Macroeconomics 11, no. 2 (2019): 1-39. https://doi.org/10.1257/mac.20170388
- Putnam, Robert D. Bowling Alone: The Collapse and Revival of American Community. Simon and Schuster, 2000.
- Le Corbusier. The Radiant City. Orion Press, 1967 [1935].
- Kelo v. City of New London, 545 U.S. 469 (2005). United States Supreme Court.
- Moreno, Carlos, et al. "Introducing the '15-Minute City': Sustainability, Resilience and Place Identity in Future Post-Pandemic Cities." Smart Cities 4, no. 1 (2021): 93-111. https://doi.org/10.3390/smartcities4010006
Frequently Asked Questions
What is urban planning and what do planners do?
Urban planning is the professional and governmental practice of shaping how land within cities and metropolitan areas is used, developed, and connected. Urban planners work at the intersection of government, design, economics, and social policy to guide decisions about where housing, jobs, parks, roads, schools, and infrastructure are located and how they relate to each other.In practice, planners spend much of their time administering and updating zoning codes — the legal rules that specify what can be built where. They prepare comprehensive plans or general plans that set long-term visions for a city's growth. They review development applications from builders and property owners, hold public hearings, and recommend approval or denial to elected officials. They coordinate large capital investments in infrastructure like transit systems, parks, and water supply.Beyond day-to-day administration, planners engage in longer-horizon work: studying demographic trends to anticipate future housing and transportation needs, designing streetscapes and public spaces, managing climate adaptation (like green infrastructure for flood control), and increasingly facilitating community engagement processes so that residents have a voice in decisions that affect their neighborhoods.The scope of urban planning extends to regional and metropolitan coordination, since cities are embedded in larger systems of transportation networks, labor markets, and environmental systems. Regional planning agencies often oversee transit and infrastructure investments across multiple jurisdictions. Urban planning intersects with law, economics, engineering, architecture, ecology, and political science — making it one of the most interdisciplinary applied fields in practice.
What is zoning and how does it affect housing costs?
Zoning is a system of local land-use regulation that divides a jurisdiction into zones — residential, commercial, industrial, and mixed-use — and specifies what kinds of buildings and activities are permitted in each zone. Zoning ordinances typically specify not just land use but also density (how many housing units per acre), setbacks (how far buildings must be from property lines), minimum lot sizes, parking requirements, and building height limits.The United States adopted Euclidean zoning after the Supreme Court upheld it in Euclid v. Ambler Realty (1926), and its basic framework has shaped American cities ever since. The key feature is separation of uses: single-family homes in one zone, apartments in another, shops and offices somewhere else. This separation, once considered a public health advance to separate homes from industrial pollution, now functions primarily as a constraint on housing supply.The connection to housing costs is straightforward once you understand supply and demand. When zoning restricts the supply of housing — by prohibiting apartments in most of a city, mandating minimum lot sizes that make new homes expensive to build, or requiring large amounts of parking that makes construction uneconomical — the supply of housing cannot keep up with demand. When more people want to live in a city than there are homes available, prices rise.Economist Edward Glaeser and others have estimated that restrictive zoning adds tens or even hundreds of thousands of dollars to the cost of homes in high-demand cities like San Francisco, New York, and Boston. Reformers argue that allowing more density — especially near transit stations — is among the most powerful tools available to reduce housing costs, cut carbon emissions from commuting, and expand access to opportunity.
What did Jane Jacobs argue about cities?
Jane Jacobs was a journalist and urban activist whose 1961 book 'The Death and Life of Great American Cities' became one of the most influential works in urban thought. Writing at the height of urban renewal — when federal money was being spent to demolish dense, mixed-use neighborhoods and replace them with modernist housing projects and highways — Jacobs mounted a detailed empirical and philosophical case against the reigning orthodoxy.Her central arguments revolved around what she called the conditions that generate urban vitality. She identified four indispensable factors: mixed primary uses (offices, residences, entertainment in the same neighborhood so streets are active at different hours); short blocks (so pedestrians have many route options and can walk between destinations); buildings of varying age (so that both prosperous and marginal businesses can find affordable space); and density (enough people to support local commerce and informal social contact).Jacobs introduced the concept of 'eyes on the street' — the idea that a safe neighborhood is one where residents and shopkeepers, going about their daily lives, naturally observe the public space and deter crime by their presence. This was the opposite of the modernist approach of setting towers in the middle of large open grounds with no ground-floor activity.She also critiqued the dominant approach to urban renewal as fundamentally misunderstanding how cities work. Planners treated diversity as disorder to be cleaned up; Jacobs argued diversity was the source of urban vitality. Clearing old neighborhoods to build superblocks and towers in the park did not create better cities — it destroyed the intricate social networks and economic ecosystems that made neighborhoods livable. Her arguments have been broadly vindicated by subsequent urban research and by the observable failure of many urban renewal projects.
How does urban design affect health and wellbeing?
Urban design affects health through multiple interacting pathways — physical activity, air quality, noise exposure, social connection, access to green space, and exposure to environmental hazards.The most consistently documented pathway is physical activity. Walkable neighborhoods — characterized by mixed land uses, connected street networks, sidewalks, and destinations within walking distance — are associated with higher rates of walking and lower rates of obesity, cardiovascular disease, and diabetes. Research consistently shows that residents of walkable urban neighborhoods are more physically active than residents of car-dependent suburbs, even after controlling for individual characteristics. The effect is not trivial: one meta-analysis estimated that doubling walkability scores was associated with a 12% reduction in body mass index.Air quality is another major pathway. Urban highways running through residential neighborhoods — precisely the kind of infrastructure that Robert Moses built through the Bronx — expose nearby residents to elevated levels of particulate matter, nitrogen oxides, and other pollutants associated with asthma, cardiovascular disease, and premature death. The placement of highways and industrial facilities near low-income and minority communities is a major environmental justice issue.Access to green space — parks, street trees, urban forests — is associated with lower stress, better mental health, and reduced mortality. Urban heat islands, where dense hard surfaces create elevated temperatures, cause heat-related illness and death disproportionately affecting elderly and low-income residents without air conditioning. Green infrastructure (urban tree canopy, green roofs, parks) mitigates heat islands.Social isolation is increasingly recognized as a major public health risk, comparable in magnitude to smoking. Urban design that creates spaces for casual social interaction — front porches, neighborhood parks, street life — supports the social ties associated with health and wellbeing. Cul-de-sac suburbs and residential-only zones tend to reduce these incidental social contacts.
Why is housing so expensive in cities?
Housing costs in major cities are high for reasons that combine fundamental economics with specific policy choices. On the demand side, cities concentrate jobs, amenities, and social networks in ways that make them attractive places to live. When the economy grows and creates jobs, more people want to live in successful cities, driving up demand for housing.On the supply side — which is where policy choices become crucial — the ability to build new housing in response to demand is severely constrained in most American and many European cities. Zoning laws that prohibit multifamily housing in large swaths of cities prevent new apartments from being built where demand is highest. Lengthy and expensive permitting processes delay and sometimes kill projects. Environmental review laws, which were designed to protect the environment, are sometimes weaponized by existing homeowners to block new housing in their neighborhoods. Minimum parking requirements, which mandate that every new housing unit include one or two parking spaces, dramatically raise construction costs and reduce the number of units that can fit on a given site.The effect of restricted supply is predictable: when more people want housing than housing exists, prices rise. Research by economists including Ed Glaeser, Joe Gyourko, and Chang-Tai Hsieh suggests that restrictive zoning in high-productivity cities like New York, San Francisco, and San Jose has reduced American GDP by billions of dollars annually by preventing workers from moving to places where they would be most productive.Housing costs are also affected by construction costs (which have risen sharply), interest rates (which affect how much buyers can borrow), and speculative investment. But economists across the political spectrum broadly agree that supply restrictions are the primary driver of the housing affordability crisis in high-demand cities.
What is transit-oriented development?
Transit-oriented development (TOD) is an approach to urban planning and real estate development that concentrates higher-density, mixed-use development within walking distance of transit stations — typically within a quarter to half mile of train or rapid bus stops. The idea is to create neighborhoods where residents can conveniently walk to the transit station and then reach jobs, shopping, and entertainment without a car.The rationale for TOD is grounded in both transportation and housing economics. Transit infrastructure is expensive — a single subway station can cost hundreds of millions of dollars. To justify this investment, stations need enough riders to generate fare revenue and enough surrounding development to generate the tax base to service public debt. Low-density single-family development around transit stations wastes the investment and ensures that most residents still drive. High-density mixed-use development around stations maximizes ridership, reduces per-capita infrastructure cost, and creates walkable neighborhoods.TOD also reduces greenhouse gas emissions and household transportation costs. Car ownership is one of the largest expenses in American household budgets, and households living in walkable, transit-accessible neighborhoods spend significantly less on transportation. Research by the Center for Neighborhood Technology found that housing and transportation costs combined — sometimes called the 'true affordability' burden — are much lower in transit-accessible neighborhoods than in car-dependent suburbs where low home prices are offset by high transportation costs.Despite the logic of TOD, many transit agencies own land around their stations that is developed at low density or as surface parking lots — a legacy of the era when transit agencies were designed to move vehicles rather than shape land use. TOD advocates argue that developing this land would simultaneously increase transit ridership, generate revenue for transit agencies, and create more affordable and sustainable urban neighborhoods.