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Report n°1: The new constraints of urban development

The development of cities around the world

A general process of spatial expansion
On all continents, a relative decline in average urban growth rates has been observed for the last 20 or 30 years, compared to those of the preceding decades. This declining trend in demographic growth becomes more obvious if fixed perimeters are used, as a general process of spatial expansion occurs everywhere. The extension of urban sprawl along communication routes often precedes the type of sprawl in which empty areas are filled.

Besides these general forms of urban sprawl, the patterns of peripheral expansion turn out to be extremely heterogeneous in terms of type of housing conditions, population pattern, means of protecting structures, construction type and social categories concerned. Despite geographical, socio-cultural and political situations differing greatly from one metropolitan area to the next, the processes of urban expansion are similar.

In metropolitan areas in developing countries, the informal urbanisation of the outskirts is a classic working-class practice, whether in the form of clandestine housing developments that fail to comply with the planning regulations, or in the form of illegal occupation of sites without the owners' consent, with inhabitants constructing their own, often precarious, dwellings. Although such illegal occupation (invasiones in Latin America, squats or squatter settlements in Asia, campements in Africa) tends to target available sites on city outskirts, which are often inappropriate for habitation, it may equally occur within the gaps in the urban area, including in central or pericentral zones.

Periurbanisation may also result from planned development, as demonstrated by single-family-home developments and other residential programmes produced by the capitalist sector or controlled by the public sector. Some projects may be on a very large scale: new districts corresponding to satellite subcities in Delhi, huge metropolitan projects in Bangkok, edge cities in Cairo, etc.

 However, the centrifugal dynamics by no means affect only the poorer people and working classes, who are pushed towards increasingly outlying locations. A dispersal of affluent households across the outer peripheral area is also in progress, facilitated, of course, by the rapid growth in car ownership, including metropolitan areas in developing countries. Luxury apartments in Cairo, some distance from the centre, the construction of vast luxury residential blocks of very low density in Sao Paulo, and luxury residential districts in Delhi's rural fringes all serve to illustrate this phenomenon.

The dispersal of city dwellers is, in some cases, driven by the search for a better living environment, which turns into a process of rurbanisation, illustrated by the proliferation of datchas in the countryside and forests around Moscow, the transformation of farmhouses in the south of Delhi, or the conjuntos cerrados (secure residential blocks) that are springing up around the village centres in the Sabana to the north of Bogota.

In large metropolitan areas in industrialised nations, the phenomena of remote and discontinuous urban extension linked to increased car use and home ownership have also been commonly observed, the American metropolitan areas leading this phenomenon to its climax.

Similar trends on all continents
Here I will give some examples of metropolitan areas that allow me to illustrate the remark made previously.

Moscow
Inner-city Moscow is characterised by total domination of collective housing. In the last decades of the Soviet era, housing construction in Moscow was almost exclusively in the form of mass-produced vertical blocks. However, this new type of dwelling was greeted and

experienced as a promotion, and it remains positively associated with city dweller status to this day.

The territory is delimited by a ring road around 20 kilometres from the Kremlin, while outside this ring starts what is called the leisure zone, or green zone. Alongside the development of the housing market, significant property activity is developing, entirely devoted to forms of single-family housing. These are the traditional datchas, which are today becoming cottages.

The tradition of the datcha (summer residence) is an ancient one, but it only ceased to be elitist in the latter days of the communist era. This concept became popular through the "garden co-operatives", which allowed Muscovites to supplement their resources. Then the residents themselves had their garden chalets converted into datchas, when it was made legal to build permanent constructions there. Since the 1990s, economic liberalisation and the birth of a property market have multiplied the amount of housing on offer around villages or on new sites. The concept of a cottage, in other words a solid house with modern comforts, is superimposed on that of a datcha, in wood, whereas the datchas themselves were equipped for winter stays. Permanent constructions are thus taken into consideration.

Altogether, the phenomenon is reaching considerable proportions, since two-thirds of Moscow's population have direct access to a datcha, or have access through relatives. However, the world of datchas is a long way from being equipped for everyday urban life, and the urban status still remains historically and psychologically linked to the apartment, yet access roads are improving and mindsets are changing. So the possibility of a two-sided Moscow cannot be ruled out: an individualist Moscow would eventually respond to the collectivist city.

Another phenomenon can also be seen, relatively marginal in inner-city Moscow but extraordinarily active within the agglomeration: the appearance of districts containing detached housing or luxury residential blocks. Prestigious apartment buildings or luxury detached houses have a common concern for security modelled on their American counterparts: electric barriers, permanent security guards, underground parking and common services for the residents. This new style of urban living in sheltered housing is currently undergoing rapid development in all the outskirts of the agglomeration, beyond the city's administrative limits.

Cairo
Two opposing trends can be observed in Cairo. On the one hand, the'verticalisation' of the old city, which aims to make the expensive land, drawn from the precious delta, more profitable and, on the other hand, an extension of the city's outskirts in the form of new districts. In fact, an increasing number of a new type of top-of-the-range residential accommodation is being developed along the desert roads, with easy motorway access. These are known as edge cities (in reference to American cities that developed around motorway junctions). These private, secure and guarded developments correspond to the city's new image for the Muslim elite. The big attraction of these residential colonies, besides the security aspect and a less polluted environment, is the presence of discos, clubs, theme parks and tourist attractions.

This new market trend is in fact due to demand from affluent classes who are disillusioned with urban life in new cities and want to escape from a metropolis that has become too busy.

Delhi
In Delhi, the proliferation of illegal housing developments has contributed decisively to the development of the city's outskirts. Essentially, these sites were originally farmland that could not be developed, purchased by unscrupulous developers from farmers in the surrounding villages, now assimilated into the city, and then resold to individuals after being divided into plots of land. As these developments failed to observe any planning regulations, they are not recognised by the municipality and are considered illegal.

Since the mid-90s, the increasing number of reinforced dwellings found in numerous shanty towns is accompanied by frequent additions of floors to accommodate a growing family or to let a room and thus profit from an additional income. We are therefore witnessing a process of residential densification, sometimes considerable, in already congested districts in lanes that are still too narrow.

In addition, a dispersal of the affluent classes towards the rural outskirts can be observed, causing competition for land use in the agricultural belt around the city, and more specifically for farmhouses. These properties were originally actual farms within agricultural business, and therefore governed by planning regulations specifically designed to limit the expansion of constructed surfaces in comparison with natural or cultivated areas. Today, the agricultural role of such areas has often been forgotten, and now they are simply luxury, spacious villas, surrounded by vast landscaped parks and protected by surrounding walls. They have been developed for a high-income population, giving them real havens of peace and greenery right on the doorstep of a capital that is among the most polluted in the world.

Faced with this reality, the authorities now tend to change the planning documents and allow the division of properties with a view to creating residential housing developments.

However, in the absence of an efficient public transport network serving the metropolitan area, the spectacular rise of individual means of transport has enabled the establishment of good quality and luxury residential districts on the rural fringes, for those who can afford the cost of long daily car journeys to and from work.

American cities
In the United States, around the largest population centres, the process of sprawl began in the first half of the 19th century. However, after 1850 the sprawl intensified under the effect of more sustained population growth in these cities, and also as collective means of transport were deployed (tramways, trains), allowing real-estate developers to provide new residential areas seeking to satisfy the needs of the developing middle classes. This process is primarily of a social nature: the residential pattern was formed logically as the middle classes distinguished and distanced themselves from the working-class areas, squeezed into old districts which thus turned into ethnic enclaves as a result of continued immigration.

With the end of the 19th century, the development of services which helped to increase the social standing of the middle classes and the economic integration of immigrants who arrived before 1870 gave a new impetus for sprawl, even if property and real-estate production continued with blocks that were still often quite small, along routes served by tramways or in city blocks concentrated around the stations. In fact, the sprawl was still limited by means of transport. The era of the car, with mass production beginning in earnest during the 1920s, most certainly made way for a real boom in suburban housing.

Programmes for road and motorway infrastructure converged to intensify the suburbanisation, which was no longer limited to the immediate edges of the cities. At the same time, the social pattern of suburbanisation changed, as standardisation and mass

production of housing models, the type of ground used and the size of plots enabled lower purchase costs and thus opened up the suburbs or commuter zones to many more households.

During the past four decades, the sprawl has continued but has changed form. In effect, residential suburbanisation has progressed in other ways and, in particular, is no longer the only cause of sprawl. It is no longer just the residential activity that is becoming deconcentrated and dispersed, but all activities, combining to make the suburbs much more heterogeneous. This explains why even in agglomerations where demographic growth is very low, resulting in moderate demand for new dwellings, we can still see significant increases in the urbanised area.

Finally, the model of the family house, surrounded by its garden, served by the road infrastructure that has been developed, has become the housing reference model for American families.

For around ten years, New Urbanism has been on the American architectural and town-planning scene as an alternative to urban sprawl. It encourages housing developments where the principle of the single family house goes hand-in-hand with that of the town house, where the pedestrian is restored to favour and where the density of construction is therefore much greater than in the traditional suburbs or outskirts. This trend also aims to give an identity to housing estates that is able to convey a sense of community.

Furthermore, a new form of housing is today taking on more and more significant proportions. These are gated communities, the first of which, built in 1854 by a businessman, was intended as a retreat, located at a reasonable distance from Manhattan. Today, however, these are not simply golden ghettos, but consumer products aimed at middle and upper-middle classes, with different social and ethnic backgrounds. In fact white, Hispanic and Asian populations can all be found in these areas. Thus each gated community associated with a type of location and type of population seems to correspond to a real-estate market segment. The developers' desire to cover the whole of the solvent home ownership market is clear. Thus, 80% of new housing developments built in the United States are gated communities.

This is, by nature, an extremely diverse residential form, and it is difficult to simply hold onto the archetype of a secure golden ghetto.

While there were already 2,500 in the 1950s, there are now around 20,000 communities of this kind in the USA. With some accommodating up to almost 20,000 people, it is estimated that they house 8.4 million people.