Cũng có ở Tiếng việt 
(Urban specialist Dean Cira recently answered in a video 5 questions on rapidly growing cities that had been submitted to us by internet users. This post addresses a few additional questions).
Manh Ha from Vietnam asked: Urban planning currently focuses too much on having new buildings, which increases the population and construction density and reduces living environment in size. What planning model do you think Vietnam should follow?
There is a popular belief among planners and among Vietnamese generally that densities of the major urban centers of Hanoi and Ho Chi Minh City need to be reduced to improve the quality of life. But if we look at the density of Hanoi, we actually see that by Asian standards, it is not particularly dense.
Indeed the average population density of Hanoi is less than Seoul , Tianjin and Hong Kong, all of which are considered to be quite livable cities. But as we suggested in our previous video answer , planners in Vietnam and indeed everywhere need to focus on ensuring mobility for labor and consumers and affordability of land and housing for firms and households. On this score, Vietnam’s planners can do much better.
While Hanoi may not be particularly dense compared to other Asian cities, it does lack the infrastructure to support its population densities. Take a look a road space, for example. In his work for the Vietnam Urbanization Review , Alain Bertuad, a well known urban expert, shows us that in the central business district of Hanoi only 9% of the area is devoted to street space, making it similar to Bangkok which has notorious traffic congestion. Compare that to New York’s Mid-town Manhattan or Seoul’s CBD which devote about 32% and 14%, respectively both of which have excellent mobility options.
Similarly, Hanoians take fewer than 60 transit trips per year compared to about 250 for those living in Barcelona, Spain – a city of similar population density. The reason is a lack of transit infrastructure. The point here is that Vietnam’s planners need to focus not only on building new towns and buildings, but on ensuring widespread good mobility for its citizens and affordability of land and housing by appropriately planning and sequencing the development and integration of land/housing development and transport as a primary focus.
Hoang Duc Minh from Vietnam asked, Has the urbanization process attracted more people to cities or has the migration process forced cities to expand? Should we stop or restrain the migration flow to cities? Why? If yes, how can we do that?
There is some evidence to suggest that access to basic services is better in urban areas than in rural areas, and in larger urban areas than in smaller urban areas in Vietnam which is often a reason for people migrating from rural to urban areas. But it is also evident that people in Vietnam are migrating in large part for better economic opportunity (pull factors) rather than for lack of services in rural areas (push factors).
Urbanization does not guarantee economic growth and modernization, but an integral part of Vietnam’s transition from a low to middle income country and beyond may well depend on how well it manages the transition from a largely rural to an urban economy - nearly all countries become at least 50% urbanized before fully reaching middle income status.
Vietnam expects to reach that point by 2025. These are strong reasons not to attempt or restrain migration to cities. But, Vietnam will need to carefully manage the tradeoffs that will come with rapid urbanization. There is the potential for increased congestion costs, regional inequalities, increased urban poverty, urban pollution and rising land and housing prices. Some of these risks are already manifest and increasing rapidly.
At the same time, Vietnam must be ready to employ urbanization as an instrument to sustain economic growth and opportunity for all. This will mean, among other things, ensuring the economic competitiveness of key economic regions, ensuring the economic, social and environmental sustainability of cities (including small and medium sized cities) making them desirable places to live and work for all segments of society and increasing economic productivity through accelerated technological advances and a better trained, educated and mobile workforce.
Sari from Indonesia asked, I just wondered whether it is possible the blueprint of a "good" city can be applicable to other cities. If it so, why not just share and follow the benchmark. How long do you think to have Jakarta as a better place to live in?
These are some really good questions and I decided to ask my colleague Peter Ellis, who has been living and working Jakarta for the past four years what he thought. He believes that Jakarta, like many cities needs to focus a lot more on issues of connectivity and therefore needs a much better public transit system, which should focus on increasing densities around the transit routes and nodes.
This may sound counter intuitive to those of you that think Jakarta should be decreasing density, but it rings true to me. Mr. Ellis also suggests that when planning for such a change, Indonesian planners should also consider that manufacturing is already leaving Jakarta for surrounding cities where land and labor are cheaper and Jakarta is seeing a future as a service center, including financial services.
I would like to know your views on whether you think traditional urban planning methods are really applicable to today’s urbanizing countries. In many countries in Asia and in Africa, for example, we are seeing urbanization growth rates higher than 5% per year. And much if this urban growth is taking place within a context where, for example, maybe 20% of the population can afford the housing that is being produced in local markets, where high percentages of the population live and work outside of the so-called formal sector and where governance at all levels, but perhaps especially at the local level is often weak.
Most planning methods and tools assume reasonable growth rates, strong institutions and a formal economy. Are the planning methods and tools that most planners are taught and employ adequate for twenty-first century urbanization which will take place largely in the developing world?