Density Dialogues

Density: drivers, dividends and debates 

(Amended extract from a study by ULI Europe.)

As population growth continues and the world urbanises, as new cities emerge and older cities are re-populated, we face the challenging question of how to accommodate more people. For some countries this is dealt with by creating new cities, or by allowing existing cities to sprawl. But for the majority who think carefully about how to support population growth, the preferred choice is well managed and well serviced densification. This has natural advantages: densifying cities can accommodate population growth within a contained environmental footprint, they can enjoy better connectivity, amenities, open spaces, and social interaction, and they become more productive and spawn innovation. Density is a way to have better cities and to provide for all the extra people. 

Many cities want population growth and densification, especially those who have not yet reached their natural sizes, or matched previous population peaks. But many cities struggle to accommodate their rising population growth, and do not easily find space for new housing, schools, amenities, and parks. They resist density and additional population, and they fear over-crowding, loss of privacy, or the insecurity of a more anonymous city. But, in most respects, the thing they fear is a distorted idea about density, an amalgam of myths and memories of the failed densification of the past. They think of slums, of concrete jungles, and of tower blocks. They do not imagine Singapore, Paris, Barcelona, Toronto, or Vienna, all examples of cities that successfully densified in order to survive. 

We know now, better than ever before what is good density, and what is bad density, we know what drives and enables density and what inhibits or prevents it. We know that Europe, in particular, needs to embrace new density as a means to repopulate our cities and to drive forward our global leadership on the environment and our crucial position in the world’s emerging innovation economy. Much of the density we need can be created on the brownfield sites, at the transport interchanges, and in the converted shops and offices that technology releases back into our cities. But some of the density we need must come from sharing our established residential areas with more people, and using density to drive better transport, schools, and greater amenities for everyone. In the new sharing economy we learn how to trade away private space for public amenity - and the form that takes is more dense, and better facilitated, districts. 

At the heart of this discussion lies a major cultural challenge: our democracy is sometimes at odds with our long term interests. Planning and investment decisions made by democratic local governments far too often prioritise the preferences of current residents, who seek to protect what they have, over the needs and interests of citizens who have not yet arrived, or have not yet been born. 

So at the core of this project is a drive to demonstrate the value of density, to advocate for the best practices that can produce it, to bust the myths, and to start the process of informing and supporting new leaders to put density at the heart of long term planning for the future. An agenda for advocacy, demonstration, and public education. There is a fundamental case for investing in learning about density. What is needed is clear: 

i. More evaluation of city densities across the world and catalogue the ingredients of success. 

ii. Identify whether a global density benchmark can be developed to protect land from urban sprawl. 

iii. Training of planners and urbanists to be bolder and more effective in planning for density. 

iv. Support for city leaders to learn how to promote density. 

v. Create and disseminate demonstration initiatives that reveal how density works for liveability. 

vi. Support for long term planning that delivers for the future citizens and not just for present preferences. 

What is Good Density?

(Amended Extract from the CNU*)

 Highlights inlcude going back to the future to the sage of sages Jane Jacobs, who suggested—based on lively mixed-use districts she had studied across the US—that, 'the ideal big-city density is somewhere between 100 and 200 net dwellings per acre. By her calculations, the North Beach-Telegraph Hill section of San Francisco achieved a net residential density of 80 to 140 units an acre. Philadelphia’s Rittenhouse Square area contained 80 to 100 units an acre. Brooklyn Heights had 125 to 174 units an acre in its core and 75 to 124 in the rest. The most fashionable pocket of Greenwich Village boasted 124-174 units per acre, and the remainder of the Village ranged from 175 to 254 units an acre'. 

(*Congress of New Urbanism. A US organisation commited to 'the restoration of existing urban centers...the reconfiguration of sprawling suburbs into communities of real neighborhoods and diverse districts, the conservation of natural environments '. )