“Kirkland requires that any accessory dwelling units (ADUs)—often known as granny flats or in-law suites—can be no larger than 800 square feet and no higher than 15 feet above the main home. They also must come with an off-street parking space.
Of the people who applied for such permits in Kirkland since 1995, nearly half never ended up starting construction. A survey by the city in 2018 found that design constraints were the biggest difficulty applicants faced.
Kirkland’s granny flat rule is just one of countless examples of ordinances, restrictions, and red tape that have slowly wrapped up America’s cities, regulating how much people can build, where they can build it, and what they can use it for.
While often justified initially as a means of protecting public health, zoning codes have now gone far beyond nuisance laws—which limited themselves to regulating the externalities of the most noxious polluters—and control of infectious disease. They instead incorporated planners’ desires to scientifically manage cities, protect property values, and combat the moral corruption that supposedly came with high-density housing.”
“”It’s a bit counterintuitive. Very large cities have problems of pollution and congestion, which are very difficult to solve,” says Alain Bertaud, a senior research scholar at New York University’s Marron Institute of Urban Management. “In spite of all that…these messy cities, if you look at what people produce, they produce a much larger part of the [gross domestic product] than the rest of the country per capita.”
Cities at their root, says Bertaud, are labor markets where people are presented with lots of choices about where to work and companies have lots of options for whom to hire. This intense intermingling of capital and labor means innovative ideas can spread more quickly and production can become more specialized. The result is that urban economies end up producing more wealth than would be possible if the workers and firms that inhabit them were spread out among smaller communities.”
“In 1793, Philadelphia, then America’s capital, was hit with a severe outbreak of yellow fever that killed 10 percent of the city’s population. “It’s pretty shocking, and it’s something that the founding fathers had to deal with. I think it’s left out of the musical Hamilton,” says Catherine Brinkley, an assistant professor of community and regional development at the University of California, Davis.
This outbreak of yellow fever, says Brinkley, inspired the first efforts to start cleaning up city streets through mucking out gutters and creating alleyways where waste could be dumped. Cholera outbreaks in American cities in the 19th century led to the creation of the first systems that could pipe in clean water and carry away sewage.
The stubborn unwillingness of people to abandon cities even in the face of periodic epidemics gave rise to interventions that made urban life a little less deadly. In his 2011 book Triumph of the City, the Harvard economist Edward Glaeser notes that developments like municipal water service and waste collection—which he calls “self-protecting urban innovations”—led to significant reductions in urban mortality. Between the end of the Civil War and the 1920s, the death rate in New York City dropped by two-thirds. Chicago saw a similar decline over the same period, with about half that fall in mortality chalked up to the provision of clean water.
The later addition of use-segregating, density-restricting zoning codes, predicated on the now-discredited “miasma” theory that a lack of light and air was to blame for the spread of urban disease, did much less to improve public health.”
“Most folks, whether they’re medieval Parisians or modern Americans, are unwilling to spend more than 30 minutes traveling, one way, between home and work.
This iron law of urban commuting—sometimes known as Marchetti’s constant, after Italian physicist Cesare Marchetti—has profound implications for how cities look, and, particularly, how sprawling or dense they can be.
If cities exist primarily as labor markets, and people are generally only willing to spend 30 minutes getting to work, the scale of an urban area’s agglomeration effects is going to depend on (a) how many jobs your average city worker can reach within a half-hour’s travel from his home and (b) how many employees can live within 30 minutes of your average city firm.
One can imagine two basic ways of adjusting for this reality: building up to accommodate more homes and firms within a given space, or speeding travel so that more destinations can be reached in a given amount of time.
Physical limits on both building and transportation technology meant that for the first few thousand years of their existence, cities tended to be pretty small, cramped places. Jonathan English, writing for CityLab in 2019, showed that pre-industrial urban areas packed most of their populations within a mile of the city center in order to accommodate a half-hour walking commute. The 19th century brought with it innovations not just in public health but also in transportation and building construction, allowing cities to grow beyond their previous limitations.”