Abstract

During the last decades, the study of cities has been transformed by new approaches combining engineering and complexity sciences. Network theory is playing a central role, facilitating the quantitative analysis of crucial urban dynamics, such as mobility, city growth or urban planning. In this work, we focus on the spatial aspects of congestion. Analyzing a large amount of real city networks, we show that the location of the onset of congestion changes according to the considered urban area, defining, in turn, a set of congestion regimes separated by abrupt transitions. To help unveiling these spatial dependencies of congestion (in terms of network betweenness analysis), we introduce a family of planar road network models composed of a dense urban center connected to an arboreal periphery. These models, coined as GT and DT-MST models, allow us to analytically, numerically and experimentally describe how and why congestion emerges in particular geographical areas of monocentric cities and, subsequently, to describe the congestion regimes and the factors that promote the appearance of their abrupt transitions. We show that the fundamental ingredient behind the observed abrupt transitions is the spatial separation between the urban center and the periphery, and the number of separate areas that form the periphery. Elaborating on the implications of our results, we show that they may have an influence on the design and optimization of road networks regarding urban growth and the management of daily traffic dynamics.

Highlights

  • Cities evolved, and continue evolving, into different organizational patterns as a consequence of historical, political, or financial circumstances and continuous optimization [1,2]

  • Analyzing a large amount of real city networks, we show that the location of the onset of congestion changes according to the considered urban area, defining, in turn, a set of congestion regimes separated by abrupt transitions

  • These models, coined as GT and Delaunay triangulation (DT)-maximum spanning tree (MST) models, allow us to analytically, numerically, and experimentally describe how and why congestion emerges in particular geographical areas of monocentric cities and, subsequently, to describe the congestion regimes and the factors that promote the appearance of their abrupt transitions

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Summary

INTRODUCTION

Continue evolving, into different organizational patterns as a consequence of historical, political, or financial circumstances and continuous optimization [1,2]. Ones operate on separate geographic spaces.we assume that local roads are basically located at the city center, and arterial roads at the urban periphery This may seem an oversimplification of the real situation, and probably neither of both extreme cases (complete overlap or complete separation) are fully compatible with observations, as we will see, it will suffice to unveil several interesting properties of road networks related to the congestion phenomena. VI we introduce the general DT-MST model and discuss how its properties are related to the origin of the transitions

BETWEENNESS DISTRIBUTION IN CITIES
GRID-TREE MODEL FOR MONOCENTRIC CITY ROAD NETWORKS
ANALYTICAL DERIVATION OF BETWEENNESS IN THE GT MODEL
CONGESTION REGIMES
DT-MST RANDOM PLANAR MODEL
EVIDENCE OF CONGESTION REGIMES IN REAL CITIES
VIII. DISCUSSION AND PERSPECTIVES
CONCLUSIONS
Planar embedding
GT model with additive length bias noise
GT model with Delaunay noise
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