The influence of urban form on travel patterns. An application to the metropolitan area of Bordeaux

The influence of urban form on travel patterns is of growing interest among researchers. It has been notably argued that high density, mixed land use settlements reduce automobile use and distances travelled, hence energy consumption per capita. A precise characterization of urban form calls analysis at an infra-urban level. We have questioned the interaction between land use and mobility in the metropolitan area of Bordeaux, France, by using OLS regressions for usual transportation variables and a multinomial logit model for modal shares. The results confirm a strong influence of both residential and firm density on mobility patterns. Mixed land use patterns doesn’t seem to influence mobility. Some economic and demographic characteristics have an influence on travel patterns. Thus it is unavoidable to take them in account. But sometimes it leads to a logical indecision, and it is difficult to determine the direction of the causal relationship. Keywords : urban sprawl, density, compact city, land use – mobility interaction JEL classification : R12, R14, R41

The motives of mobility: an infra-urban level analysis. The case of Bordeaux, France.

The influence of urban form on travel patterns is of growing interest among researchers. It has been notably argued that high density, mixed land use settlements reduce automobile use and distances travelled, hence energy consumption per capita. A precise characterization of urban form calls analysis at an infra-urban level. We have questioned the interaction between land use and mobility in the metropolitan area of Bordeaux, France, by using OLS regressions for usual transportation variables and a multinomial logit model for modal shares. The results confirm a strong influence of both residential and firm density on mobility patterns. Mixed land use patterns doesn’t seem to influence mobility. Some economic and demographic characteristics have an influence on travel patterns. Thus it is unavoidable to take them in account. The strong interdependence between variables, and the difficulty to determine the direction of the causal relationships shows a strong degree of complexity of the problem. We’re led to conclude by proposing an explanatory framework for a better understanding of the factors of infra-urban mobility patterns.urban sprawl urban form density compact city mobility

Economics of discontinuous urban development (In French)

Although it is frequent, discontinuous (leapfrog) development has rarely been addressed by the literature, because traditional models are unable to conceive diverse urban forms. This article is a survey of theoretical explanations of discontinuous development. It follows two parts. First, taking in account uncertainty on future returns drives to include an option value in land prices. Landlords speculate on the future value of the land and may leave vacant their plot in order to take advantage of high future returns. Second, discontinuous development is the product of a preference for open space. Natural amenities are included in land prices and provoke a dispersion of developed lots. These mechanisms are reinforced by a vote “against growth” by the inhabitants, which drives to a severe control of new developments.discontinuous development, leapfrog development, speculation, amenities, urban sprawl, urban form

Economics of discontinuous urban development (In French)

Although it is frequent, discontinuous (leapfrog) development has rarely been addressed by the literature, because traditional models are unable to conceive diverse urban forms. This article is a survey of theoretical explanations of discontinuous development. It follows two parts. First, taking in account uncertainty on future returns drives to include an option value in land prices. Landlords speculate on the future value of the land and may leave vacant their plot in order to take advantage of high future returns. Second, discontinuous development is the product of a preference for open space. Natural amenities are included in land prices and provoke a dispersion of developed lots. These mechanisms are reinforced by a vote “against growth” by the inhabitants, which drives to a severe control of new developments.discontinuous development, leapfrog development, speculation, amenities, urban sprawl, urban form

Urban Sprawl and Spatial Segregation. A review (In French)

This article explores the theoretical linkages between urban sprawl and social segregation. We first present the way segregation can increase urban sprawl : according to the « flight from blight hypothesis », mechanisms of segregation may form socially homogenous areas which tend to move away from each other. Second, we show that the influence of sprawl on segregation is ambivalent. On one’s hand, it diminishes the pressure on rent ; thus the exclusion process is softened. On the other hand, it gives more achievability to bring together people who want to. This last process is reinforced by exclusionary zoning practices. A review of some empirical studies on the link between residential density and social segregation show that the direction of such a relation is unspecified. We finally argue for an analysis of the urban sprawl-social segregation linkages as from the study of residential relocations.urban sprawl, social segregation, exclusionary zoning, flight from blight

Land use mix and daily mobility. The case of Bordeaux (In French)

The question of the urban form-daily mobility interaction was recently renewed. The model of the Compact City aims at increasing densities to decrease the use of the automobile. However, the density-mobility interaction is questioned in the polycentric city : on one’s hand, suburban employment centers produce original kinds of travel, such as cross-commuting or multi-prupose travelling ; on the other hand, they facilitate co-location of jobs and housing. That’s why the reflexion on the urban form-mobility interaction goes through the quantitative aspects of urban form (density) to qualitative ones : the diversity of land use. The idea is that land use mix brings the origin and the destination of the trips closer. In this paper, we make a distinction between two types of diversity : the functional one (i.e. the jobs-housing balance) and the economic one. Both may have an impact on daily mobility. We apply this question to the case of the metropolitan area of Bordeaux. In a first step, we test a general urban form model : we notice a significant impact of the degree of diversity on travel behaviour. Thus we are led to question about the influence of the type of diversity on travel patterns. We comment these results thanks to the location behaviour of the firms according to their activity.Urban form, travel patterns, functional diversity, economic specialization

Is there an Environmental Urban Kuznets Curve? The case of polluting emissions due to daily mobility in 37 cities. (In French)

The Environmental Kuznets Curve (EKC) has given rise to a flourishing literature since the beginning of the 90’s. The EKC postulates an inverted U-shaped relationship between income and polluting emissions: there would be a level of wealth beyond which polluting emissions would decrease. Surprisingly, this issue has rarely been applied to the cities. Yet we consider such a question as a pertinent one. This article aims at analyzing the Urban EKC (UEKC) hypothesis. It tests it with a sample of 37 cities in the world. Previous studies on the UEKC hypothesis are very scarce. They are the ground for us, to define a specific methodological posture. First, we use polluting emissions per capita instead of pollutants concentrations: thus we control for the influence of urban size. Second, we only take in account pollutants due to a unique source, which is daily mobility. This makes the explanation of the income-polluting emissions relation easier, as our comments are based on a specific, well constituted literature about factors of daily mobility. We expose the theoretical mechanisms by which the UEKC due to daily mobility could be validated. The impact of income on polluting emissions is threefold : behavioural, with a direct effect and an indirect one ; technical (the environmental efficiency of the vehicles increases) ; political (planning authorities wish to evolve towards a « sustainable mobility »). The empirical part of the paper is a test of the UEKC on a sample of 37 cities in the world. We present three important results. First, the estimation of quadratic regressions gives an inverted U-shaped relationship for most of the pollutants, which doesn’t permit to invalidate the UEKC hypothesis. Second, we show that the explanation of such curves is linked to two sets of factors: individual behaviours (e.g. modal choice) and collective choices (e.g. transit supply). Third, we discuss the validity of the UEKC hypothesis, that is we seek to explain the level of polluting emissions. As many factors are entangled, we use a principal components analysis to show that the influence of income may in fact reflect the influence of both urban form and consumers’ habits on polluting emissions due to daily mobility.Environmental Kuznets Curve ; daily mobility ; urban ; polluting emissions

Is there an Environmental Urban Kuznets Curve? The case of polluting emissions due to daily mobility in 37 cities. (In French)

The Environmental Kuznets Curve (EKC) has given rise to a flourishing literature since the beginning of the 90’s. The EKC postulates an inverted U-shaped relationship between income and polluting emissions: there would be a level of wealth beyond which polluting emissions would decrease. Surprisingly, this issue has rarely been applied to the cities. Yet we consider such a question as a pertinent one. This article aims at analyzing the Urban EKC (UEKC) hypothesis. It tests it with a sample of 37 cities in the world. Previous studies on the UEKC hypothesis are very scarce. They are the ground for us, to define a specific methodological posture. First, we use polluting emissions per capita instead of pollutants concentrations: thus we control for the influence of urban size. Second, we only take in account pollutants due to a unique source, which is daily mobility. This makes the explanation of the income-polluting emissions relation easier, as our comments are based on a specific, well constituted literature about factors of daily mobility. We expose the theoretical mechanisms by which the UEKC due to daily mobility could be validated. The impact of income on polluting emissions is threefold : behavioural, with a direct effect and an indirect one ; technical (the environmental efficiency of the vehicles increases) ; political (planning authorities wish to evolve towards a « sustainable mobility »). The empirical part of the paper is a test of the UEKC on a sample of 37 cities in the world. We present three important results. First, the estimation of quadratic regressions gives an inverted U-shaped relationship for most of the pollutants, which doesn’t permit to invalidate the UEKC hypothesis. Second, we show that the explanation of such curves is linked to two sets of factors: individual behaviours (e.g. modal choice) and collective choices (e.g. transit supply). Third, we discuss the validity of the UEKC hypothesis, that is we seek to explain the level of polluting emissions. As many factors are entangled, we use a principal components analysis to show that the influence of income may in fact reflect the influence of both urban form and consumers’ habits on polluting emissions due to daily mobility.Environmental Kuznets Curve, daily mobility, urban, polluting emissions

Regulatory zoning and coastal housing prices: a bayesian hedonic approach (In French)

The priority for France’s “Grenelle II” environmental legislation is to reduce the consumption of space caused by urbanisation. The best tool for achieving this goal is zoning within a territorial planning framework. Yet zoning also tends to increase property values, due to the scarcity effects it provokes (restricting the supply of land) as well as its amenity effects (the capitalisation of land use externalities in housing pricing).\r\nThe present article studies the impact on property prices of the distance to regulated zones located on Arcachon Bay near Bordeaux in Southwest France – a region that is particularly conducive to this kind of analysis because it combines exceptional landscape quality and strong urban pressures. We have estimated a hedonic model corrected for spatial self-correlation. Heteroscedasticity is corrected using Bayesian simulation methods, as suggested by Le Sage and Parent (2006).\r\nThe findings reveal tension between urban and natural amenities in the determination of property prices. Proximity to facilities and coastal amenities increase prices. The impact on housing prices of zoning materialising through Land Use Plans (LUP) is corroborated. Protected natural zones tend to raise prices as long as long they are not used for agricultural or forestry activities. Conversely, proximity to zones of future urbanisation tends to lower housing prices.LUP zoning, Hedonic price method, Bayesian spatial econometrics, Coastal

Entre protection et ouverture : quels effets de la politique d’usage des sols sur les dynamiques de marché foncier sur le littoral aquitain ?

JOURNAUX ET REVUES / Articles scientifiquesDans cette contribution nous caractérisons et analysons l’évolution récente des politiques foncières sur le littoral aquitain, avec un focus particulier sur le bassin d’Arcachon. Nous confrontons d’abord les évolutions des zonages entre 2001 et 2010 avec celles des usages du sol. Ouverture à l’urbanisation et reclassement « naturel » sont les deux phénomènes qui retiennent toute notre attention. Ces dynamiques sont ensuite rapprochées de l’évolution des marchés fonciers. La latence entre achat et construction permet de révéler de possibles comportements spéculatifs. Enfin, nous explorons les hypothèses de capitalisation dans les prix fonciers des externalités produites par les changements de zonage. L’impact de l’ouverture à l’urbanisation se vérifie mais pas celui des reclassements en espace naturel.This article proposes an analysis of actual land use planning policies on coastal Aquitaine, with a focus on the area of Bassin d’Arcachon. We first match zoning changes between 2001 and 2010 with land use changes. New development zones and a rise in protection of “natural” uses are the main observed tendencies. Second, we link theses evolutions to land market dynamics. Time spent between buying and constructing suggests the existence of speculative behaviours. Moreover, we test whether changes in zoning produce externalities that are capitalized in land values. Our results show that potential urbanisation zones generate a price premium, but it is not the case for new “natural” zones