The periurban city: why to live between the suburbs and the countryside
Introduction
The last 30 years have witnessed the emergence of a new pattern of urban development in France, called the periurban belt.1 It is defined as a belt outside the city occupied both by farmers and commuting households Le Jeannic, 1997, Cavailhès and Schmitt, 2002. Hence, the periurban area may be viewed either as a rural area in the sense that the vast majority of its land is used for farming, or as an urban area with most of its working population commuting to the city where jobs are concentrated.2
The periurban household has been described as “living in natural surroundings, far from the city's turmoil in roomy houses with gardens while keeping a city job with the associated income” (Le Jeannic, 1997). This is reminiscent of urban economics models with amenities. However, such models typically assume a specialized residential pattern with contiguous housing. Clearly, this does not fit the periurban area. In addition, those amenities are often exogenous whereas amenities arising in periurban areas depend on the level of agricultural activities. Yet, with its clear separation between residential and working places, the periurban space forms a ring around a city that displays the monocentric pattern common to most residential location models. Therefore, it seems to us that we may appeal to urban economic theory to study periurban areas.
In this paper, we borrow ideas from land use theory and urban economics to develop a residential location model in which households may choose to live close to farmers because they value rural amenities created by the farmers.3 Rural amenities produced by farmers contribute to the well-being of consumers working in the city center, whereas farmers have a Thünian behavior in that they benefit from the city proximity through reduced transport costs for their crops. Households and farmers compete on the same land market. The equality between the bid land rents of these two types of agents gives rise to a periurban equilibrium. This is achieved through the supply of rural amenities by farmers, the level of which is determined by the interactions between farmers and households whose densities are endogenous.
In standard urban economics, the trade-off between the lot size and commuting costs yields a land rent profile that is decreasing with distance from the CBD. However, several applied findings contradict this result and have led to the development of models exhibiting negative rent gradients. The existence of amenities in the periphery of cities is one of the tools used to model these inverted gradients (Richardson, 1975, Brueckner et al., 1999, Goffette-Nagot, 2000; Irwin, this issue).
Our analysis runs along the same lines as these models but has a very different purpose. Specifically, we build a new setting in which market equilibrium conditions give rise to several equilibrium land use patterns. One of these patterns is of particular interest to us, that is, a mixed farming-residential space. Stated differently, for some parameter configurations our model yields a mixed space, which is rarely found in the existing literature although it is pretty common in the real world.4
The remainder of the paper is organized as follows. In Section 2, we provide a short description of the evolution of periurban areas in France and of their main distinctive features. Section 3 presents the model, whereas Section 4 deals with the periurban land market equilibrium. Section 5 focuses on the effects of the periurban spread on the environment and other variables affecting the quality of life. We also address the following question: is the periurban belt a permanent pattern of urban growth or just a transitory stage of evolution? Section 6 presents an attempt at calibrating our model on medium-sized French urban areas with parameters obtained from surveys or advice of experts. Findings predicted by the calibration and observed from the real word are similar. Section 7 concludes.
Section snippets
Periurban areas in France: a brief description
As shown in Fig. 1, since the 1970s, French cities and their suburbs have lost inhabitants, whereas periurban belts have gained many.5
Assumptions and notation
Space is represented by the real line X=(−∞,∞) with a CBD lying at the origin. It is assumed that all non-agricultural employment is concentrated in the CBD. There are two types of agents competing on the land market: (i) a continuum of identical households working at the CBD, with density nh(x)≥0 at x∈X and (ii) a continuum of identical farmers, with density na(x)≥0 at x∈X. The total amount of space occupied by households and farmers at x cannot exceed the available quantity of land (which is
The city–periurban–rural equilibrium
As mentioned in the introduction, several configurations may be sustained as spatial equilibria. The one that interests us is as follows: the CBD is surrounded by a specialized residential area, which is itself followed by a periurban ring and, finally, by a rural area. It is denoted C–P–R.
The procedure
The equilibrium outcome described in the foregoing sections has been obtained at the cost of many simplifying assumptions. Hence, one may wonder about the meaning of the conclusions obtained, especially when considering them for possible policy recommendations. Therefore, to assess the relevance of the model, we calibrate it on real data.
To the best of our knowledge, not that many attempts have been made to validate models of urban economics on real data (see Anas, 1987, for a survey). Since
Results
The simulations were performed as follows. We started from the foregoing initial values for the parameters w, β, Ψ(0), Φ(0), τ, t, RA, choosing γ and δ in order to get a plausible magnitude for the results. Next, we allowed each parameter to slightly vary in turn around its initial value. The values minimizing E were kept. Finally, we screened the values of δ and γ and selected δ=1.1 and γ=0.20.
The results turn out to be sensitive to the values of the land market parameters, but robust with
Conclusions
We have proposed a new model of land use that seems well adapted to French metropolitan areas, which are a combination of cities, as usually defined in urban economics, and of a mixed area of housing and farming activities, called the periurban belt. This model is very simple. On the one hand, we have Thünian farming activities that incur transport costs due to the direct sales of their crops. On the other hand, we have identical households with a Cobb-Douglas utility whose variables are
Acknowledgements
We are grateful to R. Arnott, three referees as well as M. Blanc, S. Charlot, F. Goffette-Nagot and B. Schmitt for helpful comments and discussions. This research was supported by the Ministère de l'Education, de la Recherche et de la Formation (Communauté fran çaise de Belgique), Convention 00/05-262 and by the Ministère de l'Agriculture et de la Pêche (France), Convention 01.G5.02.03.A. We are also grateful to the Institut National de la Statistique et des Etudes Economiques (INSEE) for
References (27)
- et al.
Income distribution and the residential density gradient
Journal of Urban Economics
(1992) - et al.
Congestion, land use, and job dispersion: a general equilibrium model
Journal of Urban Economics
(1999) - et al.
Why is Central Paris rich and Downtown Detroit poor? An amenity-based theory
European Economic Review
(1999) Modeling in Urban and Regional Economics
(1987)Capitalization of urban travel improvements into residential and commercial real estate: simulations with a unified model of housing, travel mode and shopping choices
Journal of Regional Science
(1995)- et al.
Development and testing of the Chicago prototype housing market model
Journal of Housing Research
(1993) Urban sprawl: diagnosis and remedies
International Regional Science Review
(2000)- et al.
Forme urbaine et mobilité: les coûts collectifs des différents types d'extension urbaine dans l'agglomération milanaise
Revue d'Economie Régionale et Urbaine
(2002) La diversité des formes de la périurbanisation en Europe
- et al.
Les mobilités résidentielles entre villes et campagnes