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

Abstract

consolidated. The need to provide theoretical cover for this situation has encouraged a new generation of polycentric theoretical models within the new urban economics (NUE). Also, central place theory and its hierarchised areas AbstractThe 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-signifi cant 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 defi ciencies 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.

Decentralization and Polycentricity: Spatial Changes of Employment in Beijing Metropolitan Area, China

“…As we all know, identifying urban employment centers is fundamental and an important component of the study of employment spatial structure [34]. The definition of centers has two aspects: first, it must have a higher density of employment than the surrounding areas, and second, it must have enough employment to influence other units' density distribution.…”

Monocentric or Polycentric? The Urban Spatial Structure of Employment in Beijing

“…Third, to deal with the potential problem that a unit surrounded by very low employment density units could be falsely identified as a candidate subcenter, we follow the threshold method of Muñiz et al [49], which uses the average employment density of the research area as the threshold for determining potential employment subcenters.…”

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

“…Numerical and statistical thresholds (density or job-ratio and em-ployment cutoffs) (Giuliano and Small, 1991;Muñiz et al, 2008) 4 , commuting flows (Bourne, 1989;Gordon and Richardson, 1996), density or job-ratio maxima (Gordon et al, 1986;McDonald, 1987;Muñiz et al, 2003;Redfearn, 2007), significant positive residuals (McDonald and Prather, 1994;McMillen, 2001;Lee, 2007), and local indicators of spatial associations (LISA) (Baumont et al, 2004;Guillain et al, 2006) are the more common procedures used 5 .…”

“…From an employment point of view, the BMR has been defined as polycentric by Muñiz et al (2008). Using municipal data, they applied a threshold methodology based on Giuliano and Small (1991) in which an employment center is a municipality with an employment density greater than the BMR's average density and an amount of employment greater than 1 per cent of the BMR's total employment.…”

“…13 Muñiz et al (2008) Muñiz et al (2003) provide an excellent overview of the historical process of the BMR's metropolitan growth and formation. inhabitants).…”