‘This is a wonderful book that should be on the desk of every architect and planner. It shows how

Public transport
: Curitiba created an efficient, fast, accessible and inexpensive bus system. 
This avoided building a subway that would have served fewer people at higher costs and 
involved decades of disruption and crippling loan repayments. Today, most travel in Curitiba 
is by bus, and its citizens use less petrol per capita than other Brazilian cities.
• 
Financial rationality
: In a risk-, cost- and profit-sharing arrangement, private companies 
operate buses and taxis under contract to the city and share the costs of terminal and road 
maintenance. Before passengers board the bus, they pay for the ride on a loading platform,
to save time and assist the disabled. Passengers pay one fare for anywhere in the city, which 
means poor commuters can afford to work wherever they can get jobs.
• 
Services
: Many social and educational services are delivered on ‘retired’ buses, including 
health classes, physical activity and dental care. Subsidized goods are also delivered to poor 
districts on buses converted into little shops. Vegetables are salvaged from farmers who had 
previously destroyed them to avoid oversupply, or due to mere visual defects.
The Curitiba innovations may be marginal, relative and modest. It is, after all, a ‘poor’ city. The point 
is that it proves money is not the barrier to improving urban life quality or equity, or even achieving 
systems change. 
So where would we begin to create low-cost, ecologically sustainable cities?
We must start with a new conception of sustainable design; one that aims to make cities and buildings 
eco-productive and socially satisfying as well as eco-efficient. In the past, the design of cities and 
buildings, like that of factories, treated the surrounding environment as an infinite source of materials 
and energy and a bottomless sink for toxins and wastes. It could be said that most urban environments 
were designed on the model of the blue bottle, an Australian jellyfish that sucks up nutrients and 
sends out toxins through its long, deadly and almost invisible tentacles. ‘Externalities’ are where a 
private development or industry directly imposes collateral damage upon society in general, as in the 
case of pollution from a factory or fertilizer runoff from a farm. They are considered ‘external’ to the 
economic framework, but are intrinsic to its design. A city or building could be considered ‘impact-
neutral’, then, only if it were in some kind of ‘ecological balance’ with its environment or bioregion.
However, even impact-neutral cities would still not be sustainable. This is because the ability of 
natural systems to regenerate and evolve is already greatly impaired.
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The ‘carrying capacity’ of nature 
itself is now inadequate to supply enough services or absorb enough toxins. Nature’s productive and 
assimilative capacity continues to decline.
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So even if all new development were, by magic, carbon 
neutral and ‘zero waste’ from this moment on, cities would still not be sustainable. Just eliminating 
the externalities of future development would not begin to address the sustainability imperative.