Transit-oriented development (TOD) has become a standard model for development. Wikipedia defines it as:
a type of urban development that maximizes the amount of residential, business and leisure space within walking distance of public transport. It promotes a symbiotic relationship between dense, compact urban form and public transport use. In doing so, TOD aims to increase public transport ridership by reducing the use of private cars and by promoting sustainable urban growth.
A TOD typically includes a central transit stop (such as a train station, or light rail or bus stop) surrounded by a high-density mixed-use area, with lower-density areas spreading out from this center. A TOD is also typically designed to be more walkable than other built-up areas, through using smaller block sizes and reducing the land area dedicated to automobiles.
Transit-oriented development is an important part of reducing greenhouse gas emissions because people who live in denser, more urban areas tend to have a smaller carbon footprint. This is because in cities jobs, housing, and services are closely colocated, so people in cities do not need to travel as far. When they do travel, they have more alternatives to automobile use, and are more likely to use public transit, walking and cycling instead. Also, in cities people tend to have less space, and therefore they have smaller homes, leading to lower emissions from heating and cooling. This is illustrated by a map of US Household Carbon Footprint by zip code included in this paper by Christopher Jones and Daniel M. Kammen that was published in Nature: Spatial Distribution of U.S. Household Carbon Footprints Reveals Suburbanization Undermines Greenhouse Gas Benefits of Urban Population Density:
Seattle adopted transit-oriented development in the early 90's by designating core areas in certain neighborhoods as urban centers or urban villages. Downtown, First Hill, the University District and Northgate were designated regionally and in Seattle's Comprehensive Plan as major urban growth centers. They include high density commercial and residential development and are high priority for service by light rail,
Urban villages are generally zoned neighborhood commercial or low to mid- rise residential; they encourage moderate density and are prioritized for more frequent transit service.
In the context of regional growth management planning, increased growth in urban centers and villages was also a central strategy in the effort to reduce development outside the urban core, in order to preserve forests and farmland. This was part of the King County's response to Washington's passage of the Growth Management Act. The intention of policymakers was that there would be plenty of housing for everyone, but it would be concentrated in urban areas where people would have reduced travel to jobs, schools, and services while still being able to go outside the city to enjoy the natural bounty that makes the region such a special place to live.
Seattle has added on to its urban villages over time, and the population has grown significantly since the urban village concept was initiated. We've grown by 25% just in the last 10 years. To the right is a map of Seattle's urban centers and villages. They make up 18% of the land area that permits residential development in the city, but in 2017 they accounted for 88% of the housing growth.
Still today compared to most peer cities, Seattle devotes more of its land area to single-family homes.
Urban Villages impact on Racial Equity
Seattle recently released the Racial Equity Analysis of Seattle 2035 and Urban Village Strategy, which concludes that the Urban Village strategy that governs our current Comprehensive Plan has a disparate impact on Seattle residents, and leads to signifcantly decreased access to housing and economic opportunity for BIPOC communities. The report recommends the following:
Growth strategy: Allow more housing types across the city with equitable access to wealth building and neighborhood opportunities
Affordable housing: Support tools to increase supply of affordable housing with community control and long-term affordability
Displacement: More and stronger anti-displacement policies and tools, including preservation of cultural communities
Inclusive economy: Data-informed tools to promote equitable economic opportunity, e.g., training and hiring preferences
Community engagement: Provide financial/technical support for sustained BIPOC involvement around comp plan update
Recent Zoning Changes
Mandatory Housing Affordability
In spring of 2019, Seattle adopted Mandatory Housing Affordability (MHA) that requires new development in core zones to either include affordable homes, or contribute to a City fund for affordable housing.
Backyard Cottages and Basement Units
In the summer of 2019, Seattle voted to allow detached accessory dwelling units (cottages or DADUs), and attached accessory dwelling units (basement units or AADUs) to provide more housing options. Backyard cottages and basement units can now be added to most lots in single family zoned areas. This allows for more housing in single family zones, but the impact is relatively modest: the Environmental Impact Statement projects 2300 units built over 10 years.
New Comprehensive Plan
Seattle is beginning work this fall on a new Comprehensive Plan, which will update Urban Growth Zones, and incorporate changes in zoning and associated changes in services, parks, schools, transit. One big question is how it will accommodate new growth; will it continue the policy of keeping most of Seattle's residential land zoned as single family or will it allow multi-family buildings? Portland recently completed a rezone which allows 4-unit apartment buildings in all previously single family zones, or up to 6 units if two of them are affordable units.
One big issue from previous years was whether to allow apodments; what is the smallest size we should allow for new apartments? Many people who live alone would rather have a small unit in the city than a larger one that requires long commute times; other people who already live in these neighborhoods are concerned about increased density and parking. One issue that may be more pressing now is the "missing middle" for family sized housing. Now that we have a large number of people who are getting to the age where they want to settle down and raise families, is there going to be a place for them to do that in the city, or will they have to move further towards the outskirts where they can afford more space, but may need to live a more car-dependent lifestyle?
Like Seattle, King County is also updating its Comprehensive Plan, and trying to allocate growth among all of its cities and towns and unincorporated areas.
Seattle and King County should give climate a very high priority when updating their Comprehensive Plans. They need to come up with a plan that will make it easier for us to reduce emissions and housing costs and one that will factor in increased needs for resilience in the face of flooding, wildfires, and climate refugees.
Allowing More Density: Point & Counterpoint
Will rezoning raise or lower property values?
Home prices in Seattle have seen dramatic increases in the last few decades, as the land within the urban growth boundaries has been built up, and the population continues to grow, increasing competition for a fixed number of available homes. For people that have a substantial proportion of their wealth invested in their house, what effect rezoning would have on their savings is an important question. While that effect is difficult to calculate in advance, here are some ways to think about it.
A rezone would allow more people to live on the same lot, which leaves each person paying less for their share of the land, but the overall price of the land could go up as a result because a group of people can afford to pay more than one person alone. Moreover, with increased density are likely to come increased amenities: stores, coffeeshops, restaurants in the vicinity, and that will make living there more desirable. Some homeowners worry that their land value would go down, because if their house is sharing the neighborhood with apartment buildings, with more people and less parking it will be less desirable.
Will rezoning raise property taxes for current owners of single family houses?
Washington State has a budget-based approach to property tax, which means that each locality figures out how much overall revenue it needs (the levy amount), and then divides that amount amongst property owners based on their accessed value. The levy amount can be increased a maximum of the lessor of 1% per year, or inflation. What this means is that your property tax increases when the rate increases, or when the value of your real estate appreciates relative to the value of other homes in the state, county, or city.
The assessed value has two parts: the value of the land itself, and the value of the improvements (the house and any other buildings on the land). The assessed value is calculated based on the sales values of other comparable properties in the neighborhood. If, for example, you lived in a neighborhood with very low turnover, and then your neighbor sold their house for significantly more, you could see your tax go up the next year in response. We don't know what affect a rezoning would have on sales prices (see the question above), but let's suppose the rezoning was applied uniformly, and the property values changed uniformly across the areas affected. The levy amount would be the same, and your share of it would be the same too, because the value of your property hasn't changed relative to other properties, so it is paying the same share. By contrast, rezoning only one particular neighborhood would change property taxes in that area. If a rezone is applied in Neighborhood A, causing its property values to rise, then Neighborhood A will, over time as accessed values change pay a larger share of the levy, and properties in other neighborhoods would pay a smaller share of the levy.
Will rezoning reduce our urban tree canopy cover?
When houses are removed and new buildings added, it is common for trees to be removed in the process, including our oldest, largest trees. This is a problem for a number of reasons: trees promote liveability, improve our mental health, reduce the heat island effect, sequester carbon, and trees around buildings even provide an insulating effect in colder weather. We already have this problem as small houses are replaced with larger houses, and most of our current tree loss is from our single family zones, but we could expect more loss from increased development after a rezoning if we don't take steps to protect the trees.
There are a number of things we could do. We can give property owners an incentive to preserve their trees by charging them a fee for every tree that is removed. This fee could be on a sliding scale so that larger trees require much larger payments; this only makes sense as they are providing much more value. Additionally, we can require property owners that remove trees to replace them with trees that will grow to a comparable size. Lastly, we could exact a developer fee whose proceeds will go to planting and maintaining trees in the city, possibility including trees in new traffic calming as is already done in some neighborhoods (e.g. Capitol Hill).
Parking policy also falls under land use. Most American cities have many more parking spaces than they have vehicles, and many would argue that these spaces could be put to better use. Moreover, more parking enables more car use in urban areas, which we are trying to reduce. Urban planners have suggested these three rules for parking:
Stop requiring off-street parking for new developments
Price street parking according to market value, based on the desireability of the space, the time of day, and the number of open spots
Spend that revenue on initiatives to better the surrounding neighborhoods
Since the pandemic, Seattle has vastly decreased the amount it charges for street parking. The maximum fee was $5, and is now $2/hr. Seattle does have a parking tax, which commercial parking lots must pay, but does not tax businesses which provide free parking to their employees or customers, which it could choose to do.
Zoning Reforms Elsewhere in the Nation
Portland passed a zoning reform that makes 4 and 6-plexes legal in any residential lot in the city. The Urbanist has an article on it.
Oregon has a property tax exemption of up to $300,000 off the assessed value for home owners who rent rooms to low or middle income tenants.
Tacoma is working on a zoning update, named Home In Tacoma. The Urbanist has an article on it: "Single-family areas would be redesignated and rezoned to Low-Scale Residential or Mid-Scale Residential zoning types, which would permit a mix of housing types like duplexes, rowhouses, and apartments."
Minneapolis passed a bill in 2019 allowing duplexes and triplexes on any residential lot. Here's a follow-up article on how it's going from Strong Towns: What if They Passed Zoning Reform and Nobody Came?
From Sightline, a round-up of zoning changes in the nation: Suddenly, Zoning Reforms are Popping Up Everywhere
This year, Washington and Oregon legalized people who aren't related to each other sharing housing in single family zones. See this article from Sightline: Oregon joins Washington to Allow Use of More Empty Bedrooms.