By definition, a community includes a multitude of people with a multitude of perspectives. When we discuss growth and development as a community it’s important to understand all of these perspectives.
As we grow, there is no “right way” to grow, only a series of trade-offs we make together. Or apart.
Because of the multitude of perspectives in our communities, these trade-offs won’t be evaluated in the same way, so I think discussion and awareness of the trade-offs we are making is critical.
These trade-offs happen whether people agree about them or not. Below are five aspects of growth I often hear discussed in Raleigh and some of my thoughts on the trade-offs associated with each aspect.
The Trade-offs of densification
When we resist densification of developed lands – depress the number of people who can use more expensive land (land that is in high demand) – those people go on to use less expensive land. This transfer in demand has one of two results, utilization of less expensive developed land or less expensive undeveloped land. There is no other option.
Utilization of less expensive developed land at best leads to increases in pricing in that neighborhood, and at worse leads to gentrification and displacement.
Increasing the demand for uses on less expensive undeveloped land, increases the feasibility of projects on that land, which can lead to the delivery of less expensive housing options – a good thing for pricing – but also increases the consumption of more land and infrastructure.
The Trade-offs of Congestion
I have heard it said that congestion is a feature of an urban environment, not a bug.
Intellectual congestion, ideas bumping into one another, can be a good thing for creativity.
Commercial congestion, the supply of goods and services bumping into the demand for goods and services, can be a good thing for the economy.
Automotive congestion on the other hand is rarely seen as a good thing.
Once a city hits the amount of automotive demand on a street that folks define as congestion, congestion can’t be “fixed”.
Once a road hits the subjective “congestion point”, one option is to add a lane to the road.
Adding a lane of travel can increase the throughput (cars per hour) of a corridor, but not the lane. Adding a lane and increasing throughput will also increase travel noise and decrease walkability. Adding a lane of travel also increases stormwater runoff and land consumption.
Adding a lane of travel can also lead to induced demand. Lowering congestion on the roadway temporarily with a new lane will attract more drivers from other routes, re-establishing congestion.
If we can’t remove congestion permanently, how else can we increase throughput (people per hour) of a travel corridor?
According to the National Association of City Planning Officials (NACTO) there are several ways to increase throughput without adding lanes. For every 10 foot wide travel lane:
- Private automobile travel has a throughput capacity of 600-1,600 people per hour.
- Mixed-traffic with frequent bus service has a throughput capacity of 1,00-2,800 people per hour.
- A two-way protected bikeway has a throughput capacity of 7,500 people per hour.
- A dedicated transit lane has a throughput capacity of 4,000-8,000 people per hour.
- A sidewalk has a throughput capacity of 9,000 people per hour.
- On-street transit (bus or rail) has a throughput capacity of 10,000-25,000 people per hour.
Said a different way, while you can’t permanently fix a congested area, you can increase throughput in many ways. Adding a dedicated transit lane can provide as much throughput equal to adding five lanes of private motor vehicle travel. Which would you rather have in your town, a five-lane highway or a transit line?
The Trade-offs of Infrastructure
Adding infrastructure as a place grows, including adding streets, sidewalks, and transitways, has an impact on the installation and maintenance cost of that infrastructure.
Most infrastructure can be measured in linear feet per person (water and sewer lines) or coverage area per person (stormwater, pavement, law enforcement, and firefighter protection).
The higher the amount of infrastructure we use per person, the more expensive it is to install and the higher taxes we pay to maintain our systems. This tradeoff of taking up more space per person is somewhat hidden because a lot of infrastructure is invisible to the average citizens going about their daily lives.
The Trade-offs of Scale and Density
There are tradeoffs in density and intensity of building as well. Here, density means homes per acre and intensity is the total size of a building per acre of land, regardless of the number of homes.
Inexpensive land – land not in high demand – can support less expensive housing types, but not more expensive housing types. Building on inexpensive land also often requires lower density. Sometimes inexpensive land requires low density because the land is the amenity, sometimes it’s because the land is the infrastructure (septic), and sometimes it’s required by law (zoning).
The benefit to developing on less expensive land can be an increase in affordability of homes. The construction of more expensive (per square foot) homes is only feasible on more expensive land that is in high demand.
The costs can be an increase in infrastructure, consumption of land, and increase in dependence on less efficient transportation and higher congestion.
Because of the constraints of inexpensive land, a higher density of homes – even at a small scale or less expensive type of construction – can be infeasible.
Expensive land – land in high demand – can support the higher costs of more dense and intense development that isn’t supported by inexpensive land.
The higher density may come at a higher price point per square foot of home, but a lower “price point” in terms of total cost of infrastructure, land consumption, transportation costs, and in many cases overall housing cost. The average apartment in Raleigh (and most cities) costs less to build than the average single family home.
The Trade-offs of Tree Canopy
Use of expensive land, land where a lot of people want to be, also has tradeoffs on the consumption of tree canopy, farmland, and wildlife habitat.
The fewer people we allow to live on expensive land, where a lot of people want to live, the more incentive we provide those same people to make a less dense living choice. People have to live somewhere.
If we make urban-dense living more challenging the only alternative is to consume land in less dense living arrangements. This leads to increased consumption of farmland, wildlife habitat, and ultimately trees.
Urban developed land will have fewer trees per acre than a greenfield (undeveloped land) in another part of town. If we trade decreased development on the infill lot for increased development on the greenfield land, we aren’t saving trees, we are actually cutting down several multiples more! How much more is an urban tree worth to a city than a suburban tree?
Conclusion
This list is meant to be the highlights, not all inclusive. What trade-offs do you see as your community grows? How are you thinking about and acting on these trade-offs?
I’d love to hear from you. If you have any thoughts to share on the trade-offs of growth, let me know on Twitter or send me an email at [email protected]!
