Miquel-Àngel Garcia-López

Employment Decentralisation: Polycentricity or Scatteration? The Case of Barcelona

At the present time, most large cities in the world are polycentric and, at the same time, they are undergoing processes of employment decentralisation and deconcentration. It has been argued that polycentricity is just an intermediate stage between monocentricity and a more unstructured, chaotic and amorphous location model, scatteration. For the case of the polycentric Barcelona, the aims of this study are to test: whether its employment is moving from polycentricity to scatteration; and, whether its employment location model is increasingly random and unstructured. The results show that, in spite of the decentralisation and deconcentration processes, employment concentrated in centres still represents a significant percentage of total employment and new sub-centres have emerged in the periphery. What is more, the results also show an increasing influence of employment sub-centres on employment location and density conditions. As a result, polycentricity has been reinforced.

The Accessibility City - When Transport Infrastructure Matters in Urban Spatial Structure

Suburbanization is changing the urban spatial structure and less monocentric metropolitan regions are becoming the new urban reality. Focused only on centers, most works have studied these spatial changes neglecting the role of transport infrastructure and its related location model, the “accessibility city”, in which employment and population concentrate in low-density settlements and close to transport infrastructure. For the case of Barcelona, we consider this location model and study the population spatial structure between 1991 and 2006. The results reveal a mix between polycentricity and the accessibility city, with movements away from the main centers, but close to the transport infrastructure.

The Effect of Employment Sub-centres on Population Density in Barcelona

The polycentric models of the new urban economics (NUE) predict that population density decreases while increasing the distance to employment centres. In contrast with this, some studies have calculated non-significant gradients or even positive ones, which appear to threaten seriously the usefulness of these theoretical models. Does this mean that this theoretical framework should be given up in order to understand the decision-making processes of the actors in a polycentric city and their cumulative effects on urban structure? Or, rather, is it a matter of overcoming problems with the appropriate estimating techniques? This study has tested the effect of decentralised and integrated sub-centres in the Barcelona metropolitan region on population density in 1991 and 2001. From the preliminary results, it is clear that population density increases with distance in a considerable number of the sub-centres that have sprung up as employment has decentralised. It has been detected that this result is due not so much to the higher value of more distant residential land compared with that nearer the employment sub-centres, but to deficiencies in the econometric model used. The problem is that the sub-centres belonging to this group are very close together. Once this is resolved, it is demonstrated that, although distance has less effect on decentralised sub-centres than integrated ones, in both cases the effect is negative; that is, when distance increases, population density is reduced. Therefore, the results obtained are not clearly contrary to the predictions of the theoretical models.

Suburbanization and Highways: When the Romans, the Bourbons and the First Cars Still Shape Spanish Cities

We estimate the effects of highways on the suburbanization of Spanish cities. First, we extend previous findings for the US and China by providing evidence for Europe: each additional highway ray built between 1991 and 2006 produced a 5 per cent decline in central city population between 1991 and 2011. Second, our main contribution is at the intrametropolitan level. We find that highway improvements influence the spatial pattern of suburbanization: suburban municipalities that were given improved access to the highway system between 1991 and 2006 grew 4.6% faster. The effect was most marked in suburbs located at 5–11 km from the central city (7.1%), and concentrated near the highways: population spreaded out along the (new) highway segments (4.7%) and ramps (2.7%). To estimate the causal relationship between population growth and highway improvements, we rely on an IV estimation. We use Spain’s historical road networks – Roman roads, 1760 main post roads, and 19th century main roads – to construct our candidates for use as instruments.

The Polycentric Knowledge Economy in Barcelona

This study focuses on the employment decentralization process in the Barcelona Metropolitan Region (BMR) between 1991 and 2001. Disaggregating employment data among four categories of knowledge-intensive activities (Knowledge-Intensive Services; High- Technology Industries; Producer Services; and Finance, Insurance, and Real Estate) and two groups of other employment (Other Manufacturing and Other Services), the aim is to test whether these four groups decentralized in a similar way to other employment, and whether this process encouraged them to locate in a polycentric or spatially dispersed pattern. The results show that knowledgeintensive and other employment activities decentralize in a similar way, although the former tends to be more concentrated through the formation of employment subcenters and therefore follows a polycentric location model. As a result, physical proximity is still important for numerous activities, especially those that incorporate more knowledge.

How Does Transportation Shape Intrametropolitan Growth? An Answer from the Regional Express Rail

This paper analyzes the influence of transportation infrastructure, and in particular of the Regional Express Rail (RER), on employment and population growth in the Paris metropolitan area between 1968 and 2010. In order to make proper causal inference, we rely on historical instruments and control for all other transportation modes that could be complement or substitute to the RER. A dynamic analysis accounting for spatial heterogeneity reveals that for municipalities located less than 13 kilometers from an RER station, each kilometer closer to the station increases employment and population growth by 12% and 8% respectively. Regarding the time pattern of these effects, we find no impact of the RER expansion on employment growth during the first part of the period, while the effect on population growth appears earlier but declines over time.

Anatomía de la dispersión urbana en Barcelona

No existe una definicion comunmente aceptada de dispersion urbana (urban sprawl), de modo que la investigacion aplicada ha trabajado con diferentes indicadores que pretenden a su vez capturar los distintos significados con que se ha dotado al termino. En este trabajo se mide como ha evolucionado la dispersion de la poblacion y del empleo de la Region Metropolitana de Barcelona (RMB) entre 1986 y 2001. Las dimensiones exploradas se dividen en dos grupos: i) forma urbana (desconcentracion, baja densidad y discontinuidad) y ii) estructura urbana. A diferencia de algunos trabajos donde el policentrismo y el crecimiento lineal se presentan como dos formas de dispersion, en nuestro caso contraponemos la idea de expansion urbana estructurada (lineal o policentrica) con la de expansion urbana desestructurada (amorfa, caotica o aleatoria), equiparando esta ultima con la cuarta dimension de la dispersion. Los resultados obtenidos indican que la poblacion y el empleo de la RMB se han descentralizado de forma desconcentrada y la densidad residencial se ha reducido. Sin embargo, la RMB no ha crecido de forma discontinua ni desestructurada, sino todo lo contrario.

Organization of Land Surrounding Airports: The Case of the Aerotropolis

We analyze the conditions driving the organization of the territory near airports by studying the distribution of economic activities. We consider how commercial firms, service operators, and consumers compete for land. The theoretical setting identifies an aerotropolis (airport city) as a land equilibrium outcome characterized by the following spatial sequence: services area, commercial area, residential area. Using data on the distribution of establishments in the United States, we analyze the existence and determinants of aeropolitan configurations. Estimations performed with parametric methods detect some interesting dynamic patterns affecting the density and distribution of activities around selected U.S. airports.

Do Land Use Policies Follow Road Construction

We study whether local land use policies are modified in response to enhanced demand for building generated by a new highway, and examine the extent to which this effect of land use regulations affects building activity. We focus on the case of Spain during the last housing boom (1995-2007). We assembled a new database with information about new highway segments and the modification of the land zoning status in nearby municipalities. The empirical strategy compares the variation in the amount of developable land before-after the construction of the highway in treated municipalities and in control municipalities with similar pre-treatment traits. Our results show that, following the construction of a highway, municipalities converted a huge amount of land from rural to urban uses. We also show that new highways have an impact on building activity.

Estructura espacial y densidad de población en la ZMVM 1995-2010: evolución de un sistema urbano policéntrico

En este trabajo se estima el efecto del policentrismo sobre la densidad de poblacion en la Zona Metropolitana del Valle de Mexico (ZMVM) entre 1995 y 2010. Los modelos teoricos policentricos postulan que la densidad de la poblacion debe caer a medida que la distancia a los centros de empleo aumenta. Los resultados confirman esta hipotesis a pesar de la fuerte inercia monocentrica del area. Sin embargo, se advierte una creciente desconexion entre los espacios de empleo y los de vivienda, lo cual impediria reducir la distancia de los desplazamientos entre el lugar de residencia y el de trabajo. Un producto destacable del ejercicio llevado a cabo es que la capacidad estructurante que tiene la infraestructura viaria principal tiende a reforzarse en detrimento del efecto que ejercen los subcentros de empleo sobre la densidad de poblacion.