Urban Decline and Renewal

POLS 4641: The Science of Cities

Previously

Source: Davis & Weinstein (2002), Figure 2

AI Overview:

This is the “bones, bombs, and breakpoints” framing from Davis & Weinstein (2002), run in reverse. Their paper showed that Japanese cities bombed in WWII recovered to their expected population rank by 1960 — demonstrating that agglomeration forces are powerful enough to overcome even catastrophic physical destruction.

Here we flip the question: what about cities that weren’t bombed? Detroit and St. Louis had no physical destruction, yet by 1970 both had lost a substantial share of their 1940 population and were far below any reasonable pre-war growth projection. Something was actively working against these cities — and it wasn’t atomic bombs.

Meanwhile, in the United States…

Meanwhile, in the United States…

AI Overview:

The Detroit trend goes far off the top of the chart — based on its 1880–1940 log-linear trend, a 1940 planner would have projected roughly 8.5 million people by 1970. This is higher than the figure cited previously (3.4M), which was based only on the faster 1920–1940 growth rate; the longer trend still produces a dramatic overshoot. Pittsburgh projects to ~1.8M and St. Louis to ~1.45M by 1970 — both well above their actual populations.

Meanwhile, in the United States…

AI Overview:

Detroit: 1.85M in 1950, falling to 1.5M by 1970 — well below the ~3.4M projection. St. Louis: peaked at 857k in 1950, fell to 622k by 1970 — 30% below its (already modest) projection. Both cities lost population not just relative to expectations, but in absolute terms. The question for the rest of today’s lecture is why.

Today’s Agenda

• The comparison with Japan suggests that US urban decline was not inevitable.

• Instead it reflects a deliberate policy choice—at federal, state, and local levels—to radically reinvent our cities.

• This period of “Urban Renewal” is characterized by:

  • An emphasis on large-scale, top-down urban planning

  • Historically unprecedented investments in highway infrastructure

• We’ll conclude by discussing why urban decline is often painfully slow and self-reinforcing.

The Power Broker

• You’ve read Caro’s introduction to Robert Moses — the man who, more than anyone else, physically remade mid-century New York City.

• Moses was never elected to public office; he accumulated power through a web of appointed positions and public authorities accountable to no one but the bondholders.

• “It is impossible to say that New York would have been a better city if Robert Moses had never lived. It is possible to say only that it would have been a different city.” (Caro 1975, pg. 21).

• But Moses was not unique in his philosophy or methods…

AI Overview:

The key takeaway from Caro is not just that Moses was a bad person — it’s that the institutional structure allowed him to exercise enormous power without accountability. The public authorities he created could issue bonds, hire staff, and build projects without going through normal democratic channels.

The Cross Bronx Expressway destroyed the East Tremont neighborhood in the Bronx — a stable, working-class Jewish community. Moses knew there were alternative routes that would have caused less displacement. He chose the most destructive one.

Urban Renewal

Take 5-10 minutes to explore these before-and-after aerial photographs. Which city looks most dramatically different, and why?

High Modernism

• The changes we see in US urban landscapes reflect an intellectual movement that Scott (1998) calls “High Modernism”.

  • Characterized by a love of rectangles, open space, strict separation of uses, and a general zest for tearing everything down and starting over.
  • Most closely associated with the architect Le Corbusier.

• The High Modernist dream was that, by building cities according to a rational plan, they would eliminate the inefficiency, disorder, and poverty of the organic city.

  • In postwar America, they would get their chance.

Anyone who has played SimCity/Cities Skylines has shared this dream! :-D

AI Overview:

Le Corbusier’s Plan Voisin (1925) proposed demolishing 60 blocks of central Paris north of the Seine and replacing them with 18 uniform cruciform towers surrounded by greenery. It was never built in Paris, but the philosophy was enormously influential on postwar housing projects in the US and UK.

The key failure mode: planners could see the disorder and density of working-class neighborhoods as problems to be solved. What they couldn’t see — because it wasn’t legible — was the social fabric: the corner stores, the street life, the informal networks of mutual aid that Jane Jacobs would later document. More on that next week.

Urban Renewal in America

• The Housing Act of 1949 authorized federal subsidies and loans for “slum clearance” and public housing construction.

• Pruitt-Igoe (St. Louis, 1956): 33 towers for 15,000 residents, hailed as a masterpiece of modern design — demolished less than 20 years later.

• Cabrini-Green (Chicago): a similar story. High-rise towers that concentrated poverty, destroyed existing community structure, and became symbols of policy failure.

AI Overview:

Pruitt-Igoe was designed by Minoru Yamasaki — the same architect who designed the World Trade Center. It won architecture awards. The demolition of the first tower in 1972 was declared by architect Charles Jencks as the “death of modern architecture.”

The racial dimension is central: urban renewal overwhelmingly targeted Black and immigrant neighborhoods, which were labeled “blighted” and therefore subject to clearance. This was often deliberate — federal highway and housing programs were administered in ways that reinforced and extended residential segregation.

An Analogy: Scientific Forestry

• 19th-century German foresters replaced messy, diverse old-growth forests with neat rows of Norweigan spruce — optimized for timber yield.

• It worked, briefly. Then the second generation of trees collapsed. What happened?

• Planners could measure and optimize what was legible — board-feet of timber. What they couldn’t see was the complex ecology that made the forest viable.

• Urban renewal repeated this mistake: optimizing for legible metrics (population density, green space, traffic flow) while destroying the social fabric that made neighborhoods function.

AI Overview:

Scott’s scientific forestry example is the heart of Seeing Like a State. The German term is Normalbaum — the “normal tree,” a standardized unit that could be counted, projected, and optimized. The monoculture forests looked rational on paper and produced excellent yields in the first rotation. By the second rotation they were dying, because the planners had eliminated everything that wasn’t timber: the fungi, the leaf litter, the insects, the diversity of species that maintained soil health.

The urban renewal parallel is direct. Planners could count housing units, measure lot coverage, and project traffic flows. What they couldn’t count — and therefore didn’t value — was the corner store that extended credit to regulars, the stoop where neighbors watched each other’s children, the informal networks of mutual aid that Jane Jacobs documented in Greenwich Village. Moses and his contemporaries saw disorder; what they were actually seeing was complexity they lacked the tools to understand.

Highways and Suburbanization

• This period also saw unprecedented federal investment in highway infrastructure.

• The Interstate Highway System is a remarkable feat of civil engineering. But it also contributed to urban decline in two ways:

  • Displacement: demolished hundreds of urban neighborhoods, displacing more than 1 million people from their homes (US DOT estimates).

  • Suburbanization: made it practical to live far from city centers, draining population and tax base from the urban core.

Did Highways Cause Suburbanization?

• This is a surprisingly thorny chicken-and-egg question to answer.

• Did people move to the suburbs because of highways, or did we build highways to cities that were already suburbanizing?

Did Highways Cause Suburbanization?

A clever solution to the problem: look at the Eisenhower Administration’s original plans for the Interstate Highway System (Baum-Snow 2007).

• Cities that happened to be central nodes in the national network got more highway construction — regardless of their pre-existing growth trends.

• Each additional highway ray through a city reduced its central population by about 18%.

AI Overview:

This is a classic instrumental variable design. The instrument is a city’s position in the 1947 military highway plan. This plan was drawn up before the suburbanization of the 1950s-60s was underway, and it was designed around connecting military bases and industrial centers, not around serving any particular urban area’s growth needs.

The key assumption: cities that happened to be central nodes in the 1947 plan would have had similar suburbanization trends absent the highway system. This is plausible because the plan’s design was exogenous to the cities’ internal politics and growth dynamics.

The 18% figure per highway ray is large. Detroit got multiple highway rays — this alone could account for a substantial portion of its population loss.

Durable Housing

• Once population loss begins, cities face a structural problem: durable housing.

• Detroit built housing for 1.8 million people. Only ~640k live there today. That surplus housing stock causes property values to collapse (glaeserUrbanDeclineDurable2005?).

• US cities rely heavily on property taxes for revenue. Collapsing values mean collapsing budgets.

• This creates a vicious cycle: population loss → fiscal stress → worse services → more population loss.

AI Overview:

Glaeser & Gyourko (2005) show that declining cities are fundamentally different from growing cities. In a growing city, reduced demand leads to higher prices (because supply is inelastic in the short run). In a declining city, reduced demand leads to lower prices, because the housing stock doesn’t disappear — it just sits vacant or deteriorates.

This asymmetry is why recovery is so hard. In a growing city, high prices attract investment and new construction. In a declining city, low prices deter investment. The housing stock slowly deteriorates, neighborhoods become less attractive, and the cycle continues.

Durable Housing

• The vicious cycle of urban decline (Manville and Kuhlmann 2018):

  • Shrinking population → lower property values → less tax revenue

  • Less revenue → cuts to schools, police, sanitation

  • Worse services → more people and businesses leave

  • Repeat.

• The United States is unusual among wealthy nations where “inner city” is associated with poverty. In most of Europe, central neighborhoods are where the wealthy live.

Wrap Up

• Mid-century urban decline was not an inevitable consequence of economic forces.
• It was accelerated by deliberate policy choices:

  • Urban renewal programs demolished functioning neighborhoods in the name of modernization.

  • The Interstate Highway System made it practical and affordable to abandon the urban core.

  • Durable housing ensured that once a city started losing population, it was self-reinforcing.

• In the decades that followed, Urban Renewal sparked a grassroots political backlash that reverberates to this day.
• Next week, we read from one of Robert Moses’ key antagonists: urbanist Jane Jacobs.

References

Baum-Snow, Nathaniel. 2007. “Did Highways Cause Suburbanization?” The Quarterly Journal of Economics 122 (2): 775–805.

Caro, Robert A. 1975. The Power Broker: Robert Moses and the Fall of New York. New York: Vintage Books.

Manville, Michael, and Daniel Kuhlmann. 2018. “The Social and Fiscal Consequences of Urban Decline: Evidence from Large American Cities, 19802010.” Urban Affairs Review 54 (3): 451–89. https://doi.org/10.1177/1078087416675741.

Scott, James C. 1998. Seeing Like a State: How Certain Schemes to Improve the Human Condition Have Failed. Yale Agrarian Studies. New Haven: Yale University Press.