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The Basic Design Challenge
The Great American Suburb is "designed" by broad zoning requirements that establish one area as residential, unless you get an exception, another area as commercial, another area as industrial, and so on.
The Residential zoning that demands development of a Great American Suburb is the Single-Use, Single-Occupancy type of zoning. This says that each dwelling can have one use, and unless it gains an exception, that use has to be to serve as the residence of a single family.
Sometimes there are lot size limits, but even when there aren't there are mandatory set backs from the property lines on all sides that eliminates "townhouse" development along a street ... the single residence has to be a free standing building that stands apart from the dwellings in its area.
What this does is place a cap on population density per square foot of land. And that cap means that a public transport route has to travel farther to serve the same number of people, and the average distance from the route is much higher if a route is established for the much bigger corridor that does serve the same number of people ... reducing the appeal and therefore demand for that public transport route.
Now, the stereotype "one size fits all" solution to this is to say, "everything must be at the density that supports public transport".
That's fine for new construction in new developments, but we have this massive sunk cost in existing suburbs. And further, the cost of abandoning those residences has been cleverly spread far and wide across the electorate. That is, many people suckered into the "home ownership" con game are going to fight tooth and nail against a strategy that just says, "we are going to pursue policies that implies that your suburban house, mortgaged to the hilt, is just going to be abandoned as a post-modern ghetto".
So what to do?
Moving Away from One Size Fits All Thinking
There is a deeper problem with the Great American Suburb than the fact that its an increasingly obsolete "One Size Fits All" solution ... and that is that it is a "One Size Fits All" approach to how we live. Switching to a different "One Size Fits All" solution is not going to fix that core problem.
What's the matter with "One Size Fits All"? Its that it never fits all, and it never fits large numbers well. What we have done, therefore, is to throw subsidies of many kinds ... public, private, financial, energy ... at the problems created by the fact that the One Size does not fit very many people all that well.
So the general design philosophy here is to look for opportunities to create a greater variety of options.
So, how can variety be introduced into a single-use sprawl suburban development?
TCOD: Transit Corridor Oriented Development
There is a great deal of talk in some quarters about "transit oriented development". And, yeah, that is what I am talking about.
But in the specific context of introducing more variety in living arrangement options in a sprawl suburban development, this means very specifically that a dedicated transport corridor is put into the place that runs through the suburb, linking it to a number (it doesn't have to be all) of the important trip destinations of its residents.
A dedicated transport corridor is required, in order to break the normal sprawl development cycle, in which "road improvements" cut travel times between existing destinations and origins and undeveloped plots of land, which are then developed, which then generate traffic, which then generates congestions, which then justifies roadworks, and now we are back at the beginning of the cycle.
A dedicated transport corridor means that the increase in congestion increases, and in some cases creates, a travel time advantage for the transport in the corridor, because it does not suffer from the road congestion. That allows locations along the corridor to attract more people per square foot without a proportional increase in cars, which then increases the appeal of development of destinations accessible to the corridor, which then increases the appeal of residences accessible to the corridor.
Riding on the Back of the Envelope in a Taxicab
But saying that is grand hand sweeping ... how would this work in practice? What kind of transport corridor, and how much variety?
I'm going to use "taxicab" geometry for these back of the envelope calculations ... that is, assuming that local travel is along streets on a rectangular NS/EW grid, so that as a first approximation, the travel distance to a point that is one mile north and one mile east is 2 miles ... first 1 mile north, then 1 mile east ... and not the crow-flies distance of [sqrt(2)]miles (cf. Pythagorus, except he's dead).
OK, say that it is a heavy rail corridor, with a regional rail service, with stations 5 miles apart. Just for the sake of argument, say that the main "quick drive" catchment is 5 miles. The core "walkable" zone around each station is 1/4 mile, with an outer "long walkable" zone of half a mile.
Taxicab geometry has diamond catchments rather than the circular catchments of crows-fly geometry. The area of the diamond is the square of the sides, s2 and diagonal of the square is twice the travel radius to the center, so Mr. Pythagoras tells us:
- s2+s2=(2r)2
- 2(s2)=4(r2)
- s2=2(r2)
- area of diamond is twice the square of the travel radius
So each 1/4 mile radius diamond is 1/8 sq. mile (twice 1/16),
and the 1/4 to 1/4 mile diamond "doughtnut" is 3/8 sq. mile (twice 1/4 is 1/2, minus the 1/8 in the middle).
The "quick drive" diamond is 50 sq. miles. The overlap has a radius of 2.5 miles, so if everyone is going to the closest station, leave out the 12.5 sq. miles of overlap, and that is a catchment of 37.5 sq. mi.
Boyo, that walkable zone looks so pathetic in comparison. 1/2 sq. mile out of 37.5 is 1.3% of the transport corridor residents who get to live in the walkable zones.
Well, not quite. Inside that core walkable zone, we don't zone normal suburban sprawl ... we zone for stacked townhouse and 2nd story townhouse on top of ground floor office/commercial. for four times the density of the single use suburban sprawl. In the "fringe" zone, we zone for twice the density. So 1/8 sq. mile is the residential opportunity of a "standard" half sq. mi, and the fringe zone is the residential opportunity of a "standard" 3/4 of a mi, or 1.25 sq. mi equivalent out of (since its part of the bigger diamond), 38.75 sq. mi equivalent. So that is 3.2%.
Not impressive yet? Well, no, if we are going to leverage walkable access to the stopping train, we need a bus route ... a station to station route. Along the route, there are four more 1/8 sq. mile walkable residence zones. That's residence opportunities equivalent to 2 suburban sq. miles, making the equivalent of 3.25 sq. miles per 40.25 sq. mile, or 8%. If infill development in those locations fills up, another bus route can extend that further.
Of course, if infill development proceeds, and turns out to be lucrative to the developers involved, they may not be satisfied with infill development "hot spots" linked to the train stations ... they may push for something that will support more extensive infill development.
Suppose a light rail line is established that runs station to station. It has stops every half mile, so that around each stop is a walkable development diamond. It meanders a little, and in effect adds 10 stops between stations. That is 1.25 sq. miles in infill zoning at the suburban residence equivalence of 5 sq. miles, for a total of 6.25 per 42.5, or 14% of the residential opportunities.
Now we are talking ... 14% is 1 in 7. And that is just the start ... the train stations and bus or light rail interchanges at the heart of the system are perfect opportunities for bike and ride or electric golf cart and ride use of the rail system, which could easily add another 5% on top with proper encouragement.
Remember, the target here is not 100% switch to one particular settlement system ... its a switch to offering a variety of alternative settlements system in what used to be plain old suburbia. So an opportunity for 1 in 7 to adopt this particular alternative ... that's one healthy slice for one alternative, by my reckoning.
Who is paying for all of this
Now, this is the U. S. of A. that we are talking about, and the rule for development in the U. S. of A. is that costs and benefits of development are shared fairly. Developers get the lion's share of benefits, and developees get the lion's share of costs.
Or, to be specific about how this "lion's share" thing works, developers are the lions, and the people living in the areas being developed are the zebras.
So "the developees" are paying for this ... except ...
... except that there is also the question of who they are paying to. If they were driving, they would be paying in all sorts of ways for that ... a big chunk of change (getting bigger) that is obvious for fuel, which for almost all areas goes out of region, and increasingly goes overseas. The cost of the cars, which for almost all areas goes out of region, and increasingly goes overseas. And of course, state and local taxes for roadworks and car related policing and regulating the car transport system. And of course parking costs included in the prices of all goods and services they obtain at places with "free parking" ... which everyone gets to pay whether they needed to use the parking or not. And the cost to provide parking which is deducted from the money that their employer has available to employ people.
And if the TCOD system was put in place in anything short of a brain dead way, there are savings on flows of income out of the region (and increasingly, out of the country), because the energy efficiency of the transport system will rise.
And ... here is the leverage of the system ... that includes the people who are still driving. This TCOD encourages activities that are trip destinations to locate near stops on the corridor. Where trips are placed because near an important destination, it encourages other destinations to locate within walking distance.
Desprawling the suburb allows more and more motorists to combine more and more distinct trips.
So that is less money flowing out of the region (probably out of the country). So that is more income circulating within the local area.
And here's the benefit of a system that allows increased efficiency ... just like our current system, in the end its going to be the income generated in the local area that will pay for the local area transport system. That is true about our current mixed public/private system, and will remain true with this TCOD system and its different public/private mix.
... but there will be more income to go around ... ... because less of it has to flow out of the region to pay for running the mixed public/private system.
In the end, developers are going to be reaping profits from some kind of economic growth. Over the last sixty years, the development model has been relying on economic growth through material expansion. This system focuses on replacing that with economic growth through material efficiency.
Is this going to result in fully sustainable, renewable economic growth? Of course not ... we can only mine the current gross material inefficiency for so long before we have to start thinking about how to put our economy on a fully sustainable basis.
Still, mining that existing gross material inefficiency is a good place to start.
Midnight Oil - Dreamworld
