Tuesday, September 29, 2015

The Main Question for Urban Planners to Resolve- Sprawl or Densification?

Although an important factor, there is a compl...
Although an important factor, there is a complex relationship between urban densities and car use. (Photo credit: Wikipedia)
Density: Drivers, Dividends and Debates (32 page pdf, Greg Clark, Emily Moir, Urban Land Institute, Jun. 23, 2015) Also discussed here: Density: Drivers, Dividends and Debates (Catherine Anderson , Urban Land Institute, Jun. 23, 2015) 

 A compact city tends to be more environmentally sustainable and has generally cleaner air than one that is spread out with emphasis on making it easier for people to drive to the centre of town with emphasis on roads wherever it allows them to drive more quickly. Today we review a research paper that examines the meaning(s) of urban density, explores the many myths about sprawl and intensification and suggests better designed and more sustainable cities for the future. Cities are categorized in terms of the density of their urban core, inner city and suburbs as Low-High-Low (typical of Europe), Low-Low-Low (typical of sprawled cities in USA/Canada/Australia), Low-Low-High (Toronto, Oslo), Medium-High- High (developing world cities). High density cities enjoy a number of advantages over low density ones, including walkability, natural habitats and economic waste disposal but fears of lower livability, traffic congestion and noise/pollution in high density cities need to be mitigated. Oslo and Toronto are seen as large cities where the balance is more nearly found. 

Key Quotes:
“54 percent of the world’s population, some 3.9 billion people, live in urbanised areas. By 2050 the urban proportion of the population is projected to grow by 2.5 billion, reaching 66 percent of the total
“ how to deliver successful densification is not so obvious and is one of the most important topics of this urban decade. Good density will mark out the next generation of winning cities”
“The Downtown and Central Waterfront area [of Toronto] is the key area for both residential and commercial development, with close to 40% of approved new developments in the city. … Toronto had more high rise buildings under construction than any other city in North America from 2012 to 2014.”
“The key combination is density with place-making and infrastructure. If you have both you get a really successful city like London. If you have density without place-making you get a different kind of city.”
Vienna and Paris stand out as higher density cities which perform strongly on the positive benchmarks ….Mexico City on the other hand is a high density city that is the worst performer on both ‘good’ and ‘bad’ density indicators. …. Although less dense overall than the majority of the case study cities, Toronto is particularly successful in minimising the negative effects of density. “
some typologies:
  • Low-High-Low cities:are cities which are characterised by high density cores, but much lower density …European cities
  • Low-Low-Low cities:are those cities with expansive suburbs and high levels of car dependence, as well as spacious downtown zones. Many North American cities..
  • Low-Low-High cities:are those cities which have made conscious efforts to densify particular neighbourhoods or districts…Toronto and Oslo..
  • Medium-High-High cities:are both sprawling and dense, with crowded informal housing on the peripheries and particular pockets of very high density, around transit hubs for example… developing world cities..”
“Environmental aspects:
  • Energy consumption is reduced in compact cities.
  • denser cities are more walkable, and can provide more viable public transport options.
  • More compact urban forms have smaller physical footprints, preserving greenfield sites and natural habitats.
  • Waste disposal and management services can be more viable and economical to construct and operate at high density”
“liveability concerns (fear of overcrowding, noise and pollution, traffic, lack of green space) .. most important contemporary reasons for resistance to density, ahead of social concerns (crime, segregation) or economic concerns”

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