In a dense core, maintenance and development are vastly much costlier than in the suburbs Acquiring land for any project is going to be harder and pricier. If you close a road in a suburb to do work on it or do other construction, no big deal; in a city, you create horrible traffic problems. Politically you have to deal with 3-4x as many people per mile work of anything in a city. In an urban environment, sure fuel costs per person drop drastically, but when other costs are taken into account, I remain unconvinced it is so much cheaper. Just look how expensive it is to live in a big city in the US relative to a suburb.

PER CAPITA

You write:

"Acquiring land for any project is going to be harder and pricier. "

Yes, obviously. Of course the land is pricier in the big urban cities. This has nothing to do with what I wrote.

The resources used PER CAPITA in suburbs will be greater than the resources used PER CAPITA in a dense urban core, other things being equal. This is a simple matter of space and resource use. Resources will tend to be more heavily used in a dense urban core, therefore society gains more benefit from that those resources, assuming the point of the resource is to be used.

Compare the use of fuel in the city, and fuel in suburbs. Much fuel in the suburb is spent on automobiles, which are well known to be inefficient. In a city you will have mass transit, which offers a more efficient use of fuel, per capita.

You write:

"In an urban environment, sure fuel costs per person drop drastically, but when other costs are taken into account, I remain unconvinced it is so much cheaper."

Nowhere did I say the city was cheaper than the suburbs. I suggest the opposite - the suburbs are cheaper than the cities. And I suggest the reason why - it is because the suburbs are subsidized to a greater extent than the cities.

There is a large literature on this subject in the field of urban planning.

You can claim that in a city people will have mass transit available, but with only a few exceptions in the US that mass transit is underutilized and really only serves to get a small fraction of the urban residents to work and back; it does not serve other daily needs quite as well, so after taking mass transit back from work you will hop into your car to go get groceries or go out for some entertainment in the evening.

If these magical subsidies truly existed at the level you are suggesting they would be both obvious and a source of growing political friction given the re-urbanization of the American population. Could you point out some examples of these subsidies? [And before you start, "fuel" does not really count since it cuts both ways in this argument and urban residents to not lead significantly more fuel efficient lives than their suburban counterparts.]

Err... He capitalized "PER CAPITA".

In cities, a piece of land the size of 6 suburban homes (counting backyard) can be home to several thousand people, that's why land is expensive.

Go to Hong Kong, you'll see apartment buildings with 40 floors. On each floor there are 20 units. In each unit there are 2 rooms, a living room, a kitchen and a toilet. Each room is 2.5 metres by 2.5 metres, the living room 3 times that. Anywhere from 2 to 6 people can live in a single unit, but usually 4; The government doesn't hand out public housing with 2 rooms to only 2 people. 4 * 20 * 40 is over 3200 residents.

In the suburbs the same land is home to only around two dozen people. Thus it would make sense that in Hong Kong land could be a hundred times more expensive than in a suburb anywhere else.

A plot of land can only be home to several thousand people if you are willing to pay a lot of money to build it in that fashion. Building up is not a cost saving measure, it is a demand placed upon a plot of land as a consequence of population density. Building suburban homes for several thousand people will occupy more land than a dense urban apartment tower, but it will be an order of magnitude cheaper to build in the first place.

"Building up is not a cost saving measure"

There has been a consistent misreading in this thread, focusing on cost. My focus was not on cost, but on resource use. Nowhere did I suggest that cities were cheaper than the suburbs. I stated above that building in a city is pricier than building in the suburbs.

However, my point was, the suburbs use more resources. The biggest resource that is used in the suburbs is land. Per capita, the suburbs use up much more land than the cities do. The geographical dispersion leads to more resource use in the suburbs.

Consider electricity being carried over a wire. Some energy is lost for every kilometer the energy needs to be carried. In a city, you might have 100,000 people living in just a few blocks - the energy does not need to travel far, per capita. In the suburbs, the same 100,000 people might be spread out over many kilometers.

I have not mentioned the environmental impact, but we could discuss that too. The suburbs use up a lot of land. The suburbs have a major impact on forests and lakes and rivers, and the wildlife that depends on those forests and lakes and rivers.

It might help to engage in a thought experiment about how much land you could free up if all people clumped together in an urban area as dense as New York City. In the USA, the states of Maine, Vermont, New Hampshire and Massachusetts have a combined population a little over 9 million. New York City has a population a bit more than 8 million. Basically, if you wanted to pack all these people into another New York, you would have a city smaller than Massachusetts, and Maine, Vermont and New Hampshire would be pure, untouched, pristine forest. Mind you, I am not suggesting this is a practical idea, I'm simply offering this as a thought experiment, as a way of imagining some of the environmental benefits of density.

1) It feels like you are exaggerating population densities. Outside of some ultra high density areas in Manhattan, you aren't going to have 100,000 people in a few blocks. The density of most cities is about 3 to 4x that of suburbs, not orders of magnitude greater. (Note: I'm going off Bay Area data here).

2) Agreed on environmental costs not being accounted for. Developing suburbs would cost more if they were; how much I can't say.

3) On your thought experiment, here's something to think about: The entire world's population can fit in Texas (270,000 sq miles) at density levels found in SF neighborhoods. You'd need just over 3 Texases (or a Texas + Alaska) to do suburban density levels (~900,000 sq miles). But you would need about 19+ million sq miles for farming (russia + canada + us + china + brazil); in other words, the land use savings gained from going fully urban is a rounding error.

3a) On top of that, you already have to build out roads, wires, etc. to get to the farmland. When also given that the land everywhere can absorb some waste with little effect (septic tanks), it actually is efficient to spread the population more evenly throughout this hypothetical world.

4) Again the cost does matter. The interstate highway system has a lower cost per person and higher average utilization per person (defined as US residents) than San Francisco's Central subway does per person (SF residents). Ongoing maintenance still looks the same; San Francisco needs to spend about $51M a year on road maintenance. Sunnyvale is at $4.7M with a 6th of the population and a 3rd the density. There might be some resources saved in higher density, but something is dragging the per capita costs higher in highly dense areas.

"Yes, resource usage may be greater per capita in the suburbs, but the most expensive resource in most cases is space/land and it is very, very expensive in urban cores."

As I have said repeatedly, my focus was not on cost but on resource use. Cities use land more efficiently than suburbs. Nowhere did I say that cities were cheaper than the suburbs. I said that the cities were pricier than the suburbs. The cost and the resource use are 2 different things. In fact, you could argue that land in a city is more expensive precisely because the land is being used more efficiently.

Per capita, a city uses less land than the suburbs. This is almost definitional. A city is efficient in its use of land. Land is an important resource. This is an example of how cities are more efficient in their use of resources.

On the flip side, low density towns require more asphalt per capita and more day-to-day gasoline usage.

Overall though, it's not on the face of it obvious to me that low density is more resource intensive. I'd be interested if you have links to detailed research on the matter.

It's also not obvious to me that small towns are more subsidized. Bridges, highways, subways, etc, going into a city are all government funded. And cities like Washington D.C. and New York are basically imperial cities - they make most of their income from politically connected agencies, banks, contractors, etc.

"Many low density towns get away without a sewer system, houses can use a septic system instead."

A septic system still uses resources. In fact, per capita, a septic system is one of the most wasteful kinds of systems for handling sewage. Think of the land that a septic system needs.

Yes, think of the land, specifically the marginal cost of using said land for a septic system.

A septic system in the country can easily cost less than the comparable amount of NYC's sewer system.

True, but the question is not resources used, but cost of resources and the value of the benefits received.

Energy wise, the people in the city use far less. But that is mostly becuase they have smaller apartments and use less heat. Give everyone in the suburbs 800 sq ft and then run the comparison again.

You definition of "resource" is a little strange. Would the pebbles in the asphalt on a street in NYC see more tires run over them per year than the pebbles in the asphalt in the suburbs. Probably true. When you look at the cost of maitaining a mile of road in NYC and compare it to a mile of road in the suburbs, the difference is striking. You are spending 10x+ for everything in the city because it is a logistics nightmare.

Even something as simple as a dedicated fiber line for a business, in the suburbs they can just run a line underground easily. In the city, it is a major problem becuase everything underground is already filled, so it comes down to getting a permit to run a line through the underground manholes (an existing, and very limited, resource) and it can be difficult if not impossible.

Not to mention compare a house made of 2x4s, plywood, to one made of steel and brick. Wood grows back. Steel doesn't. Steel also uses an insane amount of energy. And construction in the city is very time consuming, energy consuming, and expensive.