The scientific controversies surrounding the comparative advantages of the compact city

Anastasia Touati, octobre 2015

While densification appears to be a consensual figure in urban public action, the compact city is also the subject of contrasting analyses on various aspects concerning its effectiveness, feasibility, accessibility, acceptability and the model of quality of life and urban equity that it underpins (Burton, Jenks and Williams 1996; Breheny 1997b; Dempsey 2010; Lindsay, Williams and Dair 2010).

First, it is the Newman and Kenworthy curve (see the fact sheet on putting densification on the political agenda) that is now the subject of significant academic debate, particularly in the methodology used (Gordon and Richardson 1989; Gomez-Ibanez 1991; Gabriel Dupuy 2002; Desjardins 2010). Jose Gomez-Ibanez criticizes, for example, the choice of the authors to focus only on the density variable when other variables such as variations in lifestyles or income are indispensable to explain mobility behaviors (Gomez-Ibanez 1991). Others, such as Xavier Desjardins, consider that the data used should be taken with caution because of the heterogeneity of the metropolises studied in the study, but also because of the practical recommendations that the authors make following their research, namely the promotion of urban density (Desjardins 2010 : 27). Similarly, Gordon and Richardson accuse Australian researchers of promoting public intervention to solve urban problems while they advocate the free functioning of the market to achieve « optimal » solutions.

In the same way, various researchers question the postulate of the effectiveness of the compact city in terms of its effects on mobility and therefore in terms of reducing the energy consumption of transport (Breheny 1995; Orfeuil 1999; Orfeuil and Soleyret 2002; Nessi 2010a). For Hélène Nessi, for example, studies in favor of the compact city suffer from significant methodological limitations. First, because urban form is analyzed through very succinct criteria, including density, which is not the only criterion that makes it possible to account for the effects of urban form on the mobility of city dwellers. Second, because most of the research that concludes that the compact city is beneficial does not take into account socioeconomic variables, even though these variables can have a considerable influence in determining mobility patterns and social categories are not uniformly distributed in urban space (Nessi 2010 : 30).

Similarly, Jean Pierre Orfeuil and Danièle Soleyret, in their study of weekend and long-distance travel, question the comparative advantages of the compact city in reducing travel by pointing to what some call the « barbecue effect »: they observe that long-distance travel is more frequent among residents of city centers than among those of the periphery (Orfeuil and Soleyret 2002). This amounts to the hypothesis that residents of dense cities, because they have more income and/or because they lack more green spaces, tend to travel farther (which implies more polluting car journeys or even plane journeys whose carbon footprint is incomparable) than residents of peripheral areas who tend to stay at home on weekends. Similarly, in the case of the United Kingdom, Michaël Breheny shows that the energy savings expected from the implementation of actions aiming at compactness appear to be low in relation to the efforts that this requires. Other actions, such as the search for innovative vehicle technologies or the increase in fuel prices, are more effective than densification actions (Breheny 1995).

Other authors also express their scepticism, particularly with regard to the ineffectiveness of policies that have already been implemented to combat urban sprawl. In France, despite the assertion of the will of political decision-makers to fight against the dilution of the urban task since the mid-1970s, urban sprawl continues at a steady pace¹ (Djellouli et al. 2010). Several analysts deplore the ineffectiveness of policies to contain urban sprawl (Comby 2008; Castel 2010; Blais, 2010; Renard 2011). Moreover, for the past two decades, we have observed not only an extension of peri-urbanization but also a phenomenon of urban sprawl, characterized by a significant decrease in the size of housing construction operations. For Jean-Charles Castel, policies to combat urban sprawl have stigmatized the development actors, i.e., single-family home builders, who are responsible for only one third of the construction of pure single-family homes (construction operations comprising only one dwelling). This has resulted in an increase in the share of diffuse construction (i.e., construction that does not require any procedure other than the filing of a building permit) on plots that are more scattered and larger than those of subdivisions, in areas that are increasingly far from city centers, where land remains affordable.

The observation is similar in Canada. For Pamela Blais, policies to control urban sprawl that rely primarily on regulations and urban design have been in place at least since the early 1970s, but without real success (Blais 2010). For her, the ineffectiveness of these policies is largely due to a lack of understanding of the mechanisms underlying urban sprawl and densification processes, but also and above all to a poor assessment of the economic aspects of subsidies and financial aid that create hidden incentives for low-density urban development.

It is also from the point of view of feasibility that some authors are interested in the production of the compact city. Michaël Bréhény points out the difficulties linked to the actions necessary for its implementation, such as the reversal of current urban decentralization trends, which are particularly prevalent in the United Kingdom (Breheny 1995). In the same vein, Nicolas Morrison shows, on the basis of a study of the particular case of Cambridge, how difficult it is to envisage the objectives of urban containment advocated in the concept of the compact city, particularly because the opportunities for urban development within the city’s construction limits have already been almost entirely used. For the author, analysis of these opportunities reveals that they will not be sufficient to accommodate much of the future housing construction (Morrison 1998).

Many researchers also raise the issue of the social acceptability of densification (Gordon and Richardson 1997; Dempsey 2010), noting the frequent opposition of residents in the neighborhoods that are desired to be densified. Others point to the deterioration of the living environment (Williams, Burton and Jenks 1996). They argue that in certain very dense neighbourhoods, further densification is perceived as leading to a state of « overdevelopment » resulting in multiple nuisances linked to greater cohabitation: air pollution, noise pollution, light pollution, increased traffic jams, loss of green space, overpopulation.

Finally, beyond the residential aspect, the question of the compatibility of densification actions with certain types of economic activities has also been raised by various authors. Louise Thomas and Will Cousins, for example, discuss the forms of development implied by the compact city and their lack of compatibility with the need for space and the necessary accessibility of spaces for economic use (Thomas and Cousins 1996). Questions therefore remain concerning the supposed virtues of the compact city and the implications of policies aimed at implementing it. The actual processes of densification also raise many questions.

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