L'évaporation du trafic, opportunités et défis pour la mobilité d'aujourd'hui et demain

This research is the result of four years of practical and scientific investigation of the phenomenon of traffic evaporation, which was considered and then demonstrated to be the opposite of traffic induction. It has anchored, in practice and in time, an orphaned and scarcely documented topic in literature which mobility planners are facing. Our research was conducted with one foot firmly grounded in the practice of mobility engineering and the other in the urban sociology of mobility behaviour. Immersed in the first field as a "project engineer" on various projects, I was able to investigate a great number of case studies and enrich the thesis with the questions of experts and commissioners. In order to answer these questions, beyond the quantitative and measurable aspects that account for the engineer's daily bread, the qualitative methods of urban sociology were mobilised to decipher the rationales for action of these individuals that make up traffic flows.This singular approach revealed the number and diversity of factors that are at play in the mechanism of traffic evaporation. These include motility, the mental cost of learning, the anchoring of modal habits and the value rationale of each individual. At the crossroads of the three research foci, which are usually treated separately and which we have combined in our case studies, i.e. the temporality of disruption, the (re)actions of the authorities and the weight of (multi)modal habits, we have been able to observe orders of magnitude beyond traffic evaporation. The results show, first of all, that traffic evaporation is achievable over the long-term of urban planning, because the time of mobility habits and learning of usage is also long, although it seems to accelerate once learning is triggered. Moreover, our results show that traffic volumes which we thought would always increase in the past can be controlled. This legitimate confidence in the reversibility of traffic induction draws attention to levers that are now, in turn, perhaps being underestimated in mobility planning.Secondly, the study of urban construction sites has shown that the keys to understanding the reactions of the traffic flow lie in the varied profiles of the individuals who make it up. Knowing their rationales for action, it is possible to assess which behavioural changes will be temporary and which will be lasting, and thus to steer them if desired.Finally, we have revealed that, in the face of the unforeseen, the activation of motility levers is strong and prompt, with the aim of overcoming personal barriers to change. In these cases, the behaviours adopted seem to last beyond the duration of the disruption.Thus, traffic evaporation appears to be much more than a new variable to be considered in mobility analyses and planning. It calls into question the logic that has driven travel planning in the automobile era.

Urban Development Processes: Methodological Investigation into the Complexity and Dynamics of Post-socialist Cities

Marija Cvetinovic

The overall objective of this thesis is to critically address, break down and reassemble the urban development process in post-socialist cities through a set of analyses that covers urban planning strategies, real-estate interventions, participatory and urban design activities. The blurred and distorted morphology of cities worldwide requires dynamic solutions and calls for proper techniques that are spatially and temporally adjusted to local socio-spatial patterns. The theoretical foundations are built upon the ordinary cities approach. It provides a unique assemblage to examine how cities are intertwined with the world, without forgetting social, cultural and historical legacies inherent to each city. The urban development of post-socialist cities is thus perceived as a complex and dynamic system that incorporates discrepant layers of urban decision-making, tracks the level of urbanity through the fluctuating links between urban agency and socio-spatial patterns, and, in general, reveals the contextual processes of maintenance, transformation and change within an urban system. The case study of the Savamala neighbourhood, is not only a scaled example of the pre-socialist material legacy, a socialist cultural and regulatory matrix, and a transitional social reality, but equally the condensed illustration of the multi-faceted circumstances of post-socialist urban development. These elements constitute the exploratory boundaries for research pertaining to a decision-making chain, urban agency networks, and to socio-spatial patterns identified in Savamala through a qualitative data collection. The methodological framework is based on a process-driven, correlational research design that blends two methods. The Actor-Network Theory creates bottom-up logical argumentation to describe urban complexity. The Multi-Agent System serves to track urban dynamics and thus outline the action framework of the research. Data analysis, triangulation and reduction rely on complex actor roles and synthesized networks, the contextualization of interests and interventions, and the distribution of urban system transitions. The combination of overlapping methods and the visualization of data in diagrams deconstructs long-term historical processes. The research findings are three-folded. Firstly, they shed light on the actors and the processes at play in Savamala, unveiling a disbalanced conglomerate of sectors: political (power-mongers), economic (profit-seekers), professional (technicians and apparatchiks), civil and cultural (on the go). The articulation of urban agency in Savamala fundamentally confirms an authoritarian distribution of roles and decisions. The empirical results of the study contribute to the operationalization of several theoretical concepts for practical investigations in ordinary cities around the world. While urban development is interpreted in terms of contextualized urban system transitions, an overarching demarcation of the level of urbanity captures the fluctuations of local socio-spatial capital. The complexity of urban actors, forces, artefacts, and the dynamics of urban networks, interrelations, processes, are depicted as a legible, data-loaded scheme of nodes and links when data is visualised through the MAS-ANT methodological approach. This research furnishes a response to the necessity of altering a deterministic concept of urban research in terms of finding an intermediary between empirical data and their graphical display.

EPFL2017

En quête d'habitat

Marie-Paule Thomas

This doctoral thesis is based on the observation that the individualization of society that is taking place today has led to new differentiations within the domains of lifestyle and residential choice. Our main hypothesis was that lifestyle influences residential choice. What kinds of differentiation with regard to lifestyles are we seeing currently? What connections are there between lifestyles, residential preferences and localization? Theoretically, the typical methods for describing residential choice and environment rely on epistemological, methodological and empirical corpuses that are quite varied and, at times, contradictory. On one hand do we find economic and demographical approaches based on the theory of the "rational" actor who attempts to optimize his localization according to "functional and economic" parameters (i.e. proximity to the workplace, the price and size of the residence depending on income and background); on the other we find sociological and anthropological approaches based on theories of social action where choice as a general rule is "socially" determined based on the individual's family ties, tradition, culture, way of living or even social position (Authier & al., 2010). Above and beyond such rational or social perspectives, other factors also influence the choices we make, including the sensitive dimension related to an individual's physical and emotional experience of space. In order to grasp all three logics of action in a single analytical frame we based our analysis on the postulate that residential choice is "plural." Thus do multiple criteria – accessibility, social rooting of families, social status of the residential residence, appreciation of the morphological qualities of the environment, etc. – figure into the decision. We assumed that based on their lifestyles that households blended one or the other of these logics of action, thus resulting in their ranking their criteria for choice in different ways. We proposed a conceptualization of lifestyle that offers a compromise between classical structuralist perspectives (Bourdieu, 1979) and individualist perspectives (Beck, 1983). In our opinion residential choices are influenced by a three-fold dimension of lifestyle: urban practices and daily life (stylization), values and urban representations (evaluation) and resources/constraints (stratification variables). Thus did we couple classic vertical forms (training, income, gender, etc.) with new horizontal forms (attitudes, opinions, values, practices, etc.) that engender social inequalities. Residential choice therefore results in a compromise (resulting from lifestyle) between the different functional, social and sensitive criteria that are or are not present in the structural, socio-historical, environmental context (potential receptiveness). Methodology The cities of Bern and Lausanne in Switzerland – two cities of comparable size but whose socio-historical backgrounds and urban structures vary significantly, particularly with regard to the quality of public transportation service – served as the field for our study. As families often use long-term residential choices to realize plans for the future, we chose to look at them. We used a combination of quantitative and qualitative methods for our empirical work. At the macro level we describe the territory using a series of functional, social and sensitive indicators that allowed us to characterize "potential receptiveness" at different levels, from citywide to neighborhood. At the micro-sociological level we conducted: a quantitative telephone survey of 500 households in each agglomeration, a qualitative survey comprised of 40 semi-directive interviews in eight neighborhoods that distinguished themselves by their geographical location (central, suburban, peri-urban) and architectural diversity. Principal findings In general our findings show that income inequalities have a discriminatory effect on the size and price of the residence as well as on the probability of finding a living space that is entirely adapted. These inequalities however only play a secondary role when it comes to explaining differences in terms of residential preferences. Whether or not the households had a weak or strong income, certain areas of the city were never considered if they did not correspond to the individual's lifestyle. To begin we showed that the immediate environment plays an important role in quality of life for families, especially with regard to the presence or absence of elements favoring children's autonomy. Access to public transportation for instance is a decisive factor in terms of localization for most families. Above and beyond these commonalities we highlighted six axes of differentiation for residential preference that indicate the qualities most sought after by families: do they want to live in an environment that first and foremost is safe, densely-populated, convivial, traditional, calm or elite? To identify how families classify choice criteria and in so doing position themselves on the different axes we did a typological analysis, thus allowing us to categorize households into seven major "residential lifestyles," each of which valued the environment's social, sensitive and functional qualities in varying degrees. Thus we found there was not a quality of life that held true for all groups but rather qualities of life. Two main groups stood out, highlighting as such the contrast between ways of living typical of (modern) industrial society, based on classic models of upward social mobility, work and material success, and those originating from (post-modern) post-industrial society, based on self-enrichment, post-materialism and criticism of so-called "bourgeois" values. The groups identified are products of the historical sedimentation of the different ways of relating to the environment that have appeared over time. By comparing our analysis of residential lifestyles and the structural/cultural differences between the cities of Lausanne and Bern we were able to highlight the impact of context on the spatial distribution of lifestyles at different scales (from nationwide to the neighborhood level). We were also able to prove that geographical distinctions such as center, suburban and peri-urban become less important; each area has its own individual functional (accessibility, services), sensitive (urban morphology, architecture) and social (social-spatial diversity, segregation) qualities. Based on these characteristics, an environment is more or less receptive to different types of residential lifestyles (can I do everything on foot in this neighborhood? Can my children go to by themselves? Is there a strong social/community dynamic?). With such a detailed qualitative and quantitative description of areas it becomes easier to determine who would like to live in a given neighborhood and who, on the contrary, would not ("describe where you live and I'll tell you who you are?"). To guarantee the success of urban development or regional policies, those responsible for planning and development need to consider urban planning not only in terms of "social mixing" but in terms of the "mixing of lifestyles" as well. Through this notion of potential receptiveness, the urbanism of lifestyles is one of the main functional conclusions of this study, for which we propose avenues of change and recommendations (how to plan and think about urban development based on use?).

EPFL2011

Planification urbaine et usages des quartiers précaires en Afrique

Benjamin Michelon

Since 2000, declarations issued in rapid succession by the international community have aimed at setting goals to drastically improve the living conditions of slum dwellers while, in the same time, the slums dwellers increased by 4,5% per year in Africa. Simultaneously, we have witnessed changes in the manner in which city residents perceive space: in today's city, the relationship between places and flows constitutes the new living space and sense of belonging (Castells, 1996). With the changes in the information society, space of flows are transformed into power flows, concentrated in space of flows which dominates more and more space of places, peripheriques areas where flows takes place everyday. Using this theory as grid, it is to re-examine the evolution of urbanization in African cities and their shantytowns. Indeed, this process of domination of the space of flows has implications for the planning approaches and uses of space of place in slums. This dual vision, putting power to the flows of space valued by the elites'cities of the living spaces of places experienced by people, is used to observe, name and understand the past and the future of cities. These elements have resulted in the formulation of a number of questions that have served as guidelines for this research. This research first targets the development of the urbanization process and the role of precarious neighborhoods: what measures are now being implemented by the authorities to reconcile the need to improve the competitiveness of African cities (advocated by donors) with the expectations of people in poor neighborhoods? In a second phase, the role of these neighborhoods' community areas is evaluated: are they a media to be valued and included in the projects to restructure the neighborhoods? Two assumptions have emerged from said questions. The first concerns the process of urbanization in African cities. This involves an analysis of the balance of power between the application of modernizing planning practices and the use of space by the residents of the neighborhoods. The second questions the role of community spaces as efficient public areas within the framework of projects to upgrade the neighborhood. The expected results of this thesis aim i) to understand the evolution of these precarious areas in the building of African cities, ii) to learn about the place and the role of community spaces and to learn from neighborhood upgrading projects. For this study, two cities were chosen: Douala (Cameroon's economic capital) and Kigali (Rwanda's political capital). For each, two methodological perspectives were adopted: the first is a comprehensive study of the entire city, based on plans, planning documents, interviews with local officials, archive documents; and the second is as a local study carried out in a market area of the city, based on observations, interviews, a questionnaire developed from a representative sample of traders, and a social and spatial analysis of the neighborhood. This approach is therefore comparative (two cities and two districts), multi-scale (two scales of analysis), historical (identifying cultural, social and political customs) and interdisciplinary (even holistic to a certain extent, taking into account different disciplines such as law, economics and urban sociology). Ultimately, this study reveals both the local specificities and differences of each city. These dissimilarities were largely developed in the presentation of these territories. They are indeed important, especially for the city of Kigali, which is undergoing a process of post-genocidal reconstruction. However, it also appears that each city's path contains a significant number of common characteristics, mainly linked to the responses they provide to urban problems: globalization today tends to standardize practices. The first element common to both areas is urban duality. This process occurs first in an urban form. The African city today remains a binary geographical entity: the city that separated the indigenous people from the settlers was succeeded by a post-colonial city marking the separation between the inherited formal city and the informal city in creation. This urban confrontation can be seen as a form of inertia, defined as a rectilinear uniform advance, suitable for the fabric of the city. The analysis of the evolution of city planning shows that projects have failed to break this logic. The delay accumulated in this field since the 80s had the effect of amplifying the phenomenon. Furthermore, this duality is reflected in the urban power struggle between the authorities and the inhabitants. On the one hand, the authorities seem determined to reproduce and keep constant both tension with and distance to the population, seeking to maintain their social control over the population. On the other hand, residents of poor neighborhoods regularly claim a "right to the city". This inertia does not mean a lack of change. This manifests itself through urban crises which temporarily break the balance. A new order is then implemented, replicating the urbanization process that prevailed in the old order. In a second phase, this research highlights the struggle for territory which emerges in these African cities. Indeed, in the midst of the general trend of inertia and reproduction, a few evolutions are worth mentioning. There is first of all a real spatial and social fragmentation of urban areas. This process occurs both in the slums and the formal rich neighborhoods mushrooming more and more on the outskirts of the city (near the urban ring roads serving these new places in which to live). To this diversification of territorial situations can be added an increasing number of slum upgrading projects, the results of which fail to meet the original targets. Moreover, even within neighborhoods, there is a fragmentation of community spaces, such as markets. The latter have undergone an important evolution since the 80s, sometimes leading to conflict between this type of local trade and the business carried out in shopping malls, which is claimed to be modern. The influence of the space of flows and the implementation planning process promote liberal "modern" sector, consisting of subsidiaries of large corporations, supermarket chains to a upper class people, while causing profound changes in space with neighborhood markets. The challenge of planning for the city of tomorrow appears to reduce this duality and to take into account this duality to prevent the development of precarious neighborhoods and urban fragmentation.

EPFL2012