Like any kind of central planning, it usually seems to go wrong, but never mind. Over the years, I have become fairly convinced by a theory about optimal layout that works just as well at the small scale (a few dozen houses in a village) as at a large scale (cities of millions). That theory is quite simply that it is far better having towns or villages stretched out along "branches" than to have them as a single "blob".
I've done these pictures using Excel, so of necessity they are squares, and it is quite true that at a micro level, having land divided up at right angles is better than higgedly-piggeldy. But you can imagine the cross as a Y shape or a many pointed star, and the square might be a circle or an oval or anything else.
1. Let's start by looking at a blob of nine square units - these might be a hundred yards or a mile across: 
2. The "branches" layout is also nine square units:
3. What is the first big advantage of the "branches"? It's that everybody is closer to the countryside. In a village of a few dozen houses, everybody's back garden backs onto fields; in a town of nine square miles (a town of about 150,000 people), nobody is more than half a mile from the countryside.
With the "blob", nearly half the gardens in the village do not overlook the countryside and nearly half the area of the town is more than half a mile from the countryside:
4. The other big advantage is that - rather counter-intuitively - you need to use less land for roads and journeys are shorter. With the "branches", the total length of the streets/urban motorway is ten units. There is a natural centre, which is where you end up with the pub-post office-church hall in the village, or the secondary schools-offices-shops in the town.
As people will live along the branches, nobody in the town has to travel more than half a mile to get onto a trunk road and then travel more than two-and-a-half miles into the centre. You can drop off your kids at school, go to work and then pop into the supermarket on the way home: 
If we criss-cross the "blob" with roads so that every house in the village is on a road, or as few people as possible in the town are more than half a mile from the nearest trunk road, we need twelve units of roads:
Even with twelve units of roads a few people in the town are still more than half a mile from the nearest trunk road:
The other downside of this is that instead of the centre being at the cross hairs, it will spread around the roads forming the inner square with no particular focus, so people all get in each others way in the morning and the evening getting from kids' school to work; or from the office to the shops etc.
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The moral of the story is that small villages tend to grow organically in the right way ("ribbon development"). They usually start with a few houses next to each other along a road, and if the village is at the junction of two or more roads, we end up with "branches", and the pub-post office-church hall are in the middle.
But once they are big enough, the temptation for the newcomer is to try and fill in the gaps, so that you end up with a "blob". I suppose that's the key to this; if we decide to build more buildings in any urban centre, by all means build upwards in the centre and fill in all the derelict sites first, but if the built-up area is to be expanded, it is better to keep adding bits right at the end of the branches, and if a branch gets too long, then you can split it out into two "twigs" and so on.
Greater London, for example, is a "blob" with a radius of about fourteen miles or about twenty-eight miles across. If it were divided into "branches" about 5 miles across which then split into two "twigs" about eleven miles from the centre, and the "twigs" are also five miles across and about eleven miles long (so the map looks like four capital Y letters joined at the base), we get the same surface area, but...
- the longest journey from edge to centre - taking the trunk roads which run along each "branch" or "twig" would be about twenty-two miles, which is longer than fourteen, but...
- we only need 132 miles of trunk road. If we criss-cross the "blob" with trunk roads five miles apart, we need (about) 200 miles length. So we can have 132 miles of three-lane motorways using the same area as 200 miles of dual carriageways, and in urban areas, it's not the distance you travel which matters but the speed. It's the same for urban railways, it's the number of stops which dictates journey time more than absolute distance.
- nobody is more than two-and-a-half miles from the nearest bit of countryside, instead of only a third being two-and-a-half miles or less from the countryside. All of which means that air quality is much better as there's always fresh air blowing in from somewhere.
- assuming the Y's are at a sensible angle, the tips of the Y's are only about twenty miles from the centre, so the overall footprint is not massively larger than a "blob" with a radius of fourteen miles.
It's Pudding Lane again - and big iguanas
7 minutes ago
23 comments:
An admirably clear demonstration.
It's the supreme irony of the Green Belt principle - that it actually meant that many city-dwellers were further away from the surrounding countryside than they would be with unrestricted ribbon development.
My mother - a confirmed cynic - insists that its primary purpose was to protect the property investments of the many civil servants living in rural Hertfordshire at the time.
Ribbon development is the natural way things happen, but the problem is that it knackers the functionality of major radial roads. So for any substantial city you would need to ensure that the major radial roads were on separate alignments with no frontage development.
McH, ta, "ribbon development" is the phrase I was looking for.
C, sure, people don't like living directly on a major trunk road, but that applies to either the "branches" or the "blob" layout, and as trunk roads are shorter (and probably wider) in the "branches", that's a win as well.
With 20-20 foresight, you'd build the radial roads first with railways running alongside (and sewers, utilities etc under them) and electricity pylons above. And the shops and light industrial can go along the trunk roads as a buffer between them and the housing behind.
The problem with the radial development pattern, is that you end up with undeveloped land near the centre of the settlement, where land prices are highest, so there is huge pressure to build on that land and turn the settlement into a blob. Minor illustration: the Victorian estate in London where I used to live had been planned round a large square in the middle, which contained a football pitch, to provide recreation and green space for the inhabitants. Within five years, the football pitch had been covered in houses.
There is a large village rather like that near us. It seems oddly strung out when you drive through, but then you notice just how many houses have a pleasant view.
How about entirely linear towns?
B, agreed.
The point is that if there is roughly the right amount of green open spaces then the extra value which accrues to the surrounding houses is far greater than the value of the houses which you could build on the green open space.
So if councils were to base their decisions on "whatever will maximise LVT receipts" then they will make sure that ten or twenty per cent of their urban areas are parks, playgrounds, duck ponds etc.
AKH, glad to have solved that puzzle.
Kj, in theory, they are just a town with only two "branches", no reason why it wouldn't work.
Kj, having thought about that for a while in between tidying up after a barbecue party, the linear town is too much of a good thing.
Surely, it is better to have four branches each one mile long than to have two branches each two miles long.
MW: Yeah I just thought of Roadtown as an anecdote I remembered when reading the post.
I assume you mean because each of the ends of the branches are closer to the center, right? There are other advantages as well, the diagonal distance between the ends of the branches means everyone is physically closer, but then again, people don't actually value walkability that much currently.
Kj: "I assume you mean because each of the ends of the branches are closer to the center"
Correct.
"people don't actually value walkability that much currently"
Actually most people very much do, apart from those who want to live in commuter villages in the middle of nowhere. People value walkability, busability, driveability, everything.
In advertisements for houses, it often says "Within walking distance of..."
See also this from the USA, home of the car.
Lots of 'linear towns in the USA...
London is a collection of villages. Each village is generally on a cross roads and by the nature of the topography that also means that is has parallel railways on the North / South line.
Each village then connects to the next village and then we fill in the bits in between, usually driven by bus routes / rly stns (or is it the other way about) that are within wlaking distance.
I was born in Enfield. My old man was born in Tottenham. When he were a lad there was green fields between Enfield and Palmers Green.
'Ribbon Development' was lambasted as a curse by the planners. I think because they are children who just love colouring maps and plans.
Then there was Ebenzer Howard and the Garden Cities idea.
But when is a branching a blob? Seems that the main thing is to maintain maximum frontage to green space and keeping traffic along a hub-and-spoke model, and when the city is large enough, it needs a ring road, kind of reminds me of most cities :)
L, without looking at historic records, it is now difficult to tell what are old villages swallowed up by London and what are simply commuter suburbs.
Kj, "when is a branching a blob?"
There's no absolute clear dividing line, it is a question of degree. Yes, beyond a certain size, you might need a ring road - so build one.
MW. I still think that in may ways London operates as a collection of villages. I was born North of the River. I grew up with the sure knowledge that people Sarf of the River were a bit funny like.
L, yes, it operates as a collection of villages, that's just human nature.
There are also meta-villages, i.e. people from all over London who meet up at certain places to do stuff together - for the hours that they are together in XYZ pub, golf course, concert hall, whatever, that is their "manor".
Each place of work is another kind of village, for example. Or each football team's supporters.
Nobody wants to live on a radial road if it means you can't walk to the shops, the pub,to school etc. I do 10k miles a year in driving around -nearly all in my God forsaken town. I am about to drive 4 miles into the bloody town centre to get an International Money order and perhaps order a book (they won't have it in stock).
When I was on holiday I walked to the shop to get a paper before breakfast and twenty yards to the left (of the shop-which sells absinthe btw) for a drink at 4.oo pm. I returned home to all this relentless driving around. What is the point of views of the countryside from your houses built on radials if you'd get turned off the land by farmers should you do more than walk on it.(Lola is talking sense)
DBC, steady on. All I'm talking about is the overall layout of the village or town, not what it looks like at ground level.
I'm throughly in favour of each suburb being a mini-village in its own right. I didn't say everything should be like Milton Keynes where you have to drive everywhere.
And farmers will turn you off the land whatever shape the town is, but it appears to be common ground that most people like being near or having a view over the countryside (I prefer being near or having a view over massive great parks like Epping Forest or Roundhay Park in Leeds because you can go and do stuff there).
There is also an optimum plot width, depending on the desired density, of between 5 and 6 metres. Less than 5 metres cramps the house plan. More than about 7 metres results in inefficient use of roads and other infrastructure and adds to building costs.
P, for residential, probably yes. But that depends on whether you are doing terraced, semi or detached. In urban areas, I would argue that terraced is best. But some people seem to prefer semi or detached, so those plots have to be wider.
DBC, as a rule, on the Continent, people prefer to live in towns. In the UK people prefer to live in the countryside, or near it. Because people like living in town centres on the Continent, then all the small shops in the town centres survive because it's as easy to walk to them than drive to the supermarket on the edge of town. In the UK, very few people live in the town centres, so there is no benefit in shops being within walking distance of anywhere, so everyone has to drive.
B, from what I've seen (e.g. Germany) they go for the "branches" approach to town planning, so nobody is all too far away from a park, green space, proper fields or other vaguely natural type area. That's why they are happy to live in centres, because it's only a short walk or drive from somewhere nice for a walk or a swim. I did read somewhere this is official and deliberate policy in Denmark.
Gothburg in Sweden is like that - there is continuous green all through the city centre so you can walk right across without going along busy roads. It helps that there are trams. There are also thousands of acres of land in public ownership available for everyone to use, with paths through and lakes for swimming or ice skating according to the season. So living in a flat is no hardship. In fact many people also have a summer cottage.
Phys: Gburg is a nice place, haven't been all around, by Slottsskogen is a good park I tend to visit every time I'm there. You live there btw?
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