Urban Planning

Cheonggyecheon; Seoul, Korea, before and after. Credit: Global Designing Cities Initiative

Urban planners lay out roads, bike paths, trolley and bus routes; and they advise elected politicians on the zoning regulations that determine what kinds of homes and businesses can be built where. These are powerful levers. Good urban planning can make cities and towns that are dense, walkable, and affordable, with good public transportation options and plenty of outdoor space for human life. And good planning can turn sprawling, car-centered suburbs into a patchwork of denser, in-filled areas with many of the desirable features of cities and small towns.  Bad planning can create (or maintain) cities and suburbs that are sprawling, car-dependent, inhospitable and inequitable. 

Dense, well-planned cities and towns are not only nice places to live; they are powerful solutions to four, connected climate problems.

1. Transportation.  Transportation is a large source of GHG emissions everywhere in the world.  In the US, it has been the largest source since 2017. In dense cities and towns, however, people drive much less than people do in less dense areas. This is partly because much of what people want and need is likely to be close to them, so that even if they drive, they have to go less far. But well-designed cities are also walkable; and they also offer a range of public transportation options that are not convenient or economical in less dense settings.

Amsterdam. Credit: Melissa & Chris Bruntlett

2. Heating and cooling. Cities require much less energy per person for building heat and cooling than do suburbs. This is partly because in multi-unit dwellings, one person’s ceiling is someone else’s floor, and so heat that would escape to the outdoors  in a single-family home instead helps to heat a neighbor. It is also because urban homes are typically smaller than suburban ones, so less space needs heating and cooling.

3. Embodied Carbon.  For similar reasons, although cities are full of materials like concrete and steel, they use much less of these per person than do suburbs. And so cities have much less embodied carbon – that is, carbon that was emitted in order to manufacture these materials – per person. This includes not just the embodied carbon in buildings, but also in roads and other public infrastructure. Because people travel shorter distances in cities, and walk or take public transportation more, less surface area per person needs to be devoted to roads. Here’s a way of visualizing how much less road area is needed in a place where some of the people can walk, cycle, or take a bus, compared to a place where everyone must drive everywhere.

Credit: i-Sustain

All of this means that the denser a city (or a neighborhood within a city) is, the lower its emissions per person.  If you’re familiar with New York City, you can see this pretty clearly in the map below.

Credit: New York Times.  You can see the data on which this map is based, and see similar maps of the rest of the US here.

4. Preserving nature. Because cities pack many people into a small space, they leave room for nature elsewhere. The more people who live in such cities, the fewer forests we will chop down for housing developments, and the fewer meadows we will pave over for suburban strip malls.  Every bit of land that we leave undisturbed is both a habitat for the species with which we share the planet and a carbon sink.

While cities and compact towns are almost always better than sprawling suburbs, there are huge differences between cities, and between neighborhoods in the same city or town.  Here are two cities with almost the same populations.

Credit: Smart Growth America and Transportation for America 

And here’s a freeway interchange near the city of Atlanta, alongside the city of Florence, Italy – at the same scale.

Credit: Paul Graham

The good news is: we have abundant evidence that people prefer to live in dense, walkable cities, and they’re willing to pay more to do so. 

Credit: National Association of Realtors

But if that’s true, why do so many people in the US and Canada live in sprawling, car-centric places?  There are two answers: (1) most places in the US are zoned in ways that make dense, walkable neighborhoods impossible – actually illegal to build. And (2) most places that are dense and walkable (usually, because they were built before modern zoning laws) are now zoned in ways that prevent them from becoming any more dense, and thus keep housing prices far too high for most people. Many people would love to live in the walkable neighborhoods of San Francisco, New York, or Cambridge, Massachusetts – but only the wealthy can afford to.

Two kinds of zoning laws, in particular, work together to stop more cities and town from becoming the kinds of place that people want to live in: (1) single family zoning and (2) mandatory parking minimums. 

(1) Single family, exclusionary zoning regulations mandate that, within some area, only detached, single-family homes can be built. The first single family zoning regulation in the US was enacted by Berkely, California, in 1916. Its proponents were clear about its racist aim: to keep desirable neighborhoods free of “negroes and asiatics.” US Federal courts were about to declare that cities could not exclude people on the explicit basis of race or religion. Single-family zoning provided a convenient work-around, because most immigrants and people of color could not afford to buy a single-family home. In the following decades, cities all around the US followed Berekely’s lead, so that now 70% of residential zoning in the US is exclusively for single-family homes. (By contrast, single family zoning doesn’t exist at all in most countries.) While many Americans are not aware of the explicitly racist goals that have shaped the suburbs and cities we live in, single-family zoning is still effective at segregating the places we live along lines of race and class.

One consequence of single family zoning is that American neighborhoods are polarized: areas that are not zoned for single families tend to have large, mid-rise or larger apartment buildings, with little of the “missing middle” housing that can make for some of the most interesting, affordable, walkable neighborhoods.

Credit: Missing Middle Housing

(2) Mandatory parking minimums require that when anyone builds a home or a business, they must leave off-street space for a set number of cars to park – for instance, at least one parking spot per apartment and one spot for every 300 square feet of retail space or 100 square feet of restaurant space. This means that huge parts of our cities must be given over to concrete parking lots, which forces sprawl, and makes it difficult to create walkable neighborhoods. 

Houston, Texas. Credit: Alex MacLean

It also contributes to the housing shortage in many parts of the country, and raises housing prices. When a builder wants to build new apartments, for instance, they need to build many fewer units than they could in order to leave room for required parking. 

Credit: https://www.desegregatect.org/parking

This increases the rent per unit – both because the costs of the whole apartment complex must be spread among fewer units, and because less housing will be available city-wide, as developers everywhere build fewer units on their lots.  Minimum parking requirements are estimated to add $225 per month to the cost of apartment rent, averaged across the US (more than that in high-rent cities).  Minimum parking requirements are an invisible subsidy for car-owners, and an invisible tax on everyone else.

Changing zoning and minimum parking requirements makes it possible to redesign cities and suburbs around people, instead of around cars. When we do this, all sorts of other possibilities open up. When we build buildings close enough together that not as many cars and not as many parking spots are needed, because people can walk or bike where they need to go more often, we can free up space for protected bicycle and pedestrian lanes, for frequent and fast-moving public transit, and for parks, public spaces, and streets that are places where people want to be.

Media, Pennsylvania. Credit: Visit Media PA

To get a sense of what good planning can do in neighborhoods that are now dominated by cars, take a look at these before and after pictures from the city of Amsterdam.

Before Credit: Eerste van der Helststraat, 1978 (Source: Amsterdam Archives). After Credit: Eerste van der Helststraat, today (Source: Thomas Schlijper).

Before Credit: Reguliersbreestraat, 1984 (Source: Amsterdam Archives). After Credit: Reguliersbreestraat, today (Source: Thomas Schlijper).

Resources

  • To learn more, a great place to start is with Charles Marohn Jr’s path-breaking book, Strong Towns.

His book started a movement. You can find ways to connect with the community of citizen advocates and professional planners of that movement, as well as a wealth of resources including readings and podcasts, at StrongTowns.org,