I have not calculated the "perfect" urban density. I would like to add just a few criteria for calculate the optimal density:
- Building hights correlating with sun and shade and block size and street with (the important is taht the courtyard/steet is in the right ratio to bring natural sunlight to the ground Floor
- If the first criteria is given (which depends on the locaion (in the north or on the equator) the block size is relevant (human scale) and the ratio of street versus housing land. townhouses are 15- 20 meter wide.
- after that it will be a economic and psycological questions
- I think the traffic, mooving the ppl is not the issue or gives any limitation

This is a very refreshing and fair-minded discussion of the vexed and oft-times controversial matter of density. Today, "automobile cities" worldwide generally need to strategically increase their densities in selected locations to respond to the growing range of sustainability issues facing urbanisation. This does not mean wholesale redevelopment of suburbs by replacing tracts of often beautiful homes on larger lots with a host of different kinds of multi-family housing. That is a recipe for controversy and rightly so, because the results are frequently quite appalling.

Rather, lower density cities need to identify those places, such as around railway stations (especially within about an 800 meter or ½-mile radius) or former industrial land where some form of higher density uses can be fitfully planned and developed in the context of good urban design.

Essentially, if automobile-oriented cities can develop a range of higher density centers or sub-centers around their regions that are supported by excellent transit (most often some form of rail line), then this gradual transformation of an urban region into a polycentric form will benefit more than just those who choose to live in such areas. They will provide more transit, walking and cycling accessible places for what will likely remain in such cities, at least for the foreseeable future, a suburban majority. Such centers of varying sizes can enliven suburban areas and bring many of the amenities that suburban, car-dependent residents need without adding to car use, while confining their spatial impacts to a relatively small area. An 800-meter circle has an area of only 201 ha or 497 acres.

The one critical additional point one must add to this discussion is the importance of the public realm. In simple terms, every time densities are increased something should be given back in terms of the quality of the public realm - those spaces that we all share and enjoy together. Vancouver has done a generally fine job of adding a lot of density to its urban fabrics in the context of what are often very extensive, green and attractive public areas for circulation on foot, bicycle, and the growing range of feral transport and lightly motorised modes such as pedelecs. These spaces are punctuated often by beautiful public gardens, good street furniture and other features that compensate to a high degree for the lack of personal/private open space in the form of backyards and front yards. These places become more socially-oriented and give people places to recreate and just be. People are often seen talking to each other, walking together, reading and so on. Increasingly such higher density, planned communities offer the opportunity to integrate various forms of urban agriculture which not only help to green a city but also can improve its food security and health, both physical and social.

So much of what people react to about higher density is the fact that the total "package" is just not there. More housing is squeezed in while giving nothing back to the community as a whole, such as, for example, attractive traffic-calmed and greened streets with places for people to meet in public. This feeds the "greedy developer" label which rolls so easily off the tongue and is often used to vilify density. It's up to the planning system to set the ground rules for density and the public realm and who pays for what. Developers in Vancouver now know that a superior public realm is critical in selling higher density housing because people buy a lifestyle bundle not just a dwelling.

"Density" depends on what you are measuring.

Well said. Thanks.

Another issue for density is that it shouldn't interfere with architectural character, implying that architectural character should be a determinant of what type of density to pursue. I would expect density to be better accepted with this approach. In other words, every neighbotrhood could be made denser as long as the nature and degree of density is appropriate for its character.

I don't see any reason why neighborhood's character shouldn't change. If we were stuck with the "neighborhood character" of 1800, the U.S. would be a largely rural nation with a much smaller population.

Never having had occasion before to challenge such a POV, I'll have to develop my thoughts on it over time.

A preliminary take on this is that every city was once rural or wild, and early settlements grew to become cities and shrines of civilization itself. Great cities like Paris or Rome took on such cultural and economic value for their form and style that many attempts to change their character for the sake of increased density collapsed.

Since I have a background in historic preservation, I know no one who would suggest changing the character of Paris or Rome for density. Of course, I'm aware of there having been huge events of demolition and reconstruction even in great American cities like NY. Haussman's Paris makeover was certainly a major character change, although I'm not sure how much of that was about density. I thought it had largely to do with health improvement and state control. Even so, Paris is relatively low-rise and yet one of the more densely populated cities in the western world. Which leads to my point: I don't see character change as being in anyway conducive to adding density.

First of all, when you alter character you run into resistance, and I'm suggesting that finding the subtlest means to increase density while maintaining character will tend to reduce resistance and so facilitate density in any given neighborhood.

A more systematic approach to adding density might greatly maximize the locations where density could go, as well.

It seems to me that every new building changes "character" in some way. But my sense is that when you say "character" maybe you really mean "height." Assuming that to be the case, I agree that taller buildings tend to be more controversial. As to whether they are substantively necessary to achieve transit-supportive densities or to lower housing costs, I think the right answer is probably: "sometimes." (which of course could lead to a lot of commentary!)

Height is most important. But in addition to over all height of a building, there's height of stories, window heights, etc. The two large structures in the middle of your cover picture show the uniformity of heights from ground to crown. And despite difference in stylistic detail, the geometry of one building conforms with that of its neighbor.

The density which I'd consider appropriate for keeping this above mentioned "character" would be much smaller and equally consistent (height, geometry, window size, etc.), far set back rows of structure on the roof. The issue with setting them back is that they aren't visible from street level, thus not impacting visual style. it's as thought they weren't even there. But if they are seen, they have been thoughtfully designed so as to bear a pleasing relationship with the original structures lining the street. New Urbanist like to see streets like this as roofless rooms, for which the buildings (or trees) are walls. But the roof structures are too set back to function like walls.

My point is that each neighborhood, based on its current form, needs a sympathetic sort of densification. And the appropriate form of transportation might follow from that. I admit that mine is a gentle approach, but I think it signals an extremely large degree of densification when extrapolated throughout the built environment.

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There are many features that make a place great. And further great is subjective to the person who inhabits the space. A high density area might be horrible if its a tower surrounded by parking. A lower density area with great design might be walkable. Cities which need more housing can expand without sprawling if the expansion occurs at the same densities as urban neighborhoods. Some cities are high density cores surrounded by miles of low density sprawl. others are made up of many neighborhoods of 2-5 story buildings.

I would say that there are cases where density is too low; where divining is unavoidable and the area used for lawns and parking lots is excessive. And there is density that is too high. In the U.S. it's hard understand this but places like Hong Kong do suffer problems due to density.

how so?

Extraordinarily small living spaces: http://www.dailymail.co.uk/...

Air pollution: I'm not a familiar with Hong Kong but most the Chinese mega-cites suffer from poor air pollution.

I would rather have the problem of small living spaces than the American problem of widespread homelessness. Hong Kong has about 1600 homeless- far fewer than NYC, which is comparably sized. (http://www.scmp.com/news/ho... )

As I mentioned in the U.S the perspective of small is different. you might think of 300 sq ft as small. Tens of thousands of people live in places around 15 sq ft which are refer to these as coffin apartments.

"These shocking pictures, which form part of a new exhibition by the Society for Community Organisation, reveal desperately cramped living spaces where toilets are feet away from chopping boards and rooms are the width of a single-bed mattress."

Great post.

Not sure who is asking about a perfect density, but there is density that works with various transportation models, and density that does not. https://www.planetizen.com/...

I had SO forgotten this thread, on which I posted a lot! Distressing lack of memory! But I see that some basic ideas from even long before that still hold firm:

NIMBY-ism, density and transportation are tightly intertwined. But addressing NIMBY-ism vs. density certainly requires comprehensive planning too.

- The character and feel of desirable neighborhoods need to be preserved.

- To make them denser, that feel and character must not be threatened.

- You can have unobtrusive density if you do it without changing basic architectural appearance, while avoiding socioeconomic or cultural conflict or congestion. .

- Combining density with public transportation help to alleviate congestion.

- Partnering with employees to foster telecommuting can help ease congestion.

- Depending on geography and other factors, unobtrusive architectural density can be achieved by a) adding tiny structures behind existing, visible ones, b) raising existing structures uniformly and underlaying them with half-story basements, c) adding *setback* half story strictures on top--uniformity might be nice here too, but seems less of an issue), and d) a combination, or all, of the above,.

- Planning must be done to ensure maximum compatibility of newcomers with established residents.

yes to all of this, but you realize that this only works if you get people out of cars? Otherwise, increasing density will increase the amount of cars on the roads, which will cause road rage and rampant NIMBY=ism. And, if you want to get public transit to work, you need to increase density a lot - because the maximum density for cars is way below the minimum density for transit. And the challenge is to make this plausible.

Here's an interesting post on the issue https://marketurbanismrepor...

But if you do this, and everybody is stuck in traffic, the villagers will shoot each other until you build them that transit?
Sent from my iPad

If you look at the American rail systems of the last few decades, some (most notably DC Metro) are in areas that were fairly dense beforehand. Others (such as Dallas and Houston light rail) were in areas that were not really dense enough to support this much transit. So I guess the big picture question is: which systems have worked better?

This is what I was arguing with the density paradox. I think that there is a minimum and maximum density for car based transportation, and a minimum and maximum density for transit, but there is a gap in between; meaning too dense for cars and not yet dense enough for transit. How to bridge that is the challenge, especially in places like LA where the maximum density for cars has been reached, but the minimum density for trains is still elusive.

i DID MENTION TRANSPORTATION, BUT POSSIBLY NOT STRONGLY ENOUGH: (cap lock error!)

"NIMBY-ism, density and transportation are tightly intertwined. But addressing NIMBY-ism vs. density certainly requires comprehensive planning too."

"- Combining density with public transportation help to alleviate congestion.

- Partnering with employees to foster telecommuting can help ease congestion."