City size, network structure and traffic congestion

Abstract

Keywords: City size Land use Transport network Traffic congestion dynamics Macroscopic fundamental diagram a b s t r a c t This paper presents an alternative approach for analyzing the relationship between land use and traffic congestion by employing the Macroscopic Fundamental Diagram (MFD). The MFD is an empirically observed relationship between traffic flow and traffic density at the level of an urban region, including hypercongestion, where flow decreases as density increases. This approach is consistent with the physics of traffic and allows the parsimonious modeling of intra-day traffic dynamics and their connection with city size, land use and network characteristics. The MFD can accurately measure the inefficiency of land and network resource allocation due to hypercongestion, in contrast with existing models of congestion. The findings reinforce the 'compact city' hypothesis, by favoring a larger mixed-use core area with greater zone width, block density and number of lanes, compared to the peripheral area. They also suggest a new set of policies, including the optimization of perimeter controls and the fraction of land for transport, which constitute robust second-best optimal strategies that can further reduce congestion externalities.

Valuating Surface Surveillance Technology for Collaborative Multiple-Spot Control of Airport Departure Operations

“…The fundamental observation supporting most recent research efforts is the existence of a close relationship between the number, or density, of aircraft buffered between the gate and the runway, and the runway throughput, which is the direct counterpart to the fundamental diagram of road traffic [23]. First observed experimentally by Shumsky [24], when considering Boston's Logan Airport, the runway throughput grows with the number of aircraft buffered between the gates and the runway; however, the throughput saturates past a given level of surface congestion, as shown in Fig.…”

Sustainable transportation strategies for decoupling road vehicle transport and carbon dioxide emissions

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Modeling Flood Risk for an Urban CBD Using AHP and GIS

“…Fig. 1 shows a typical city with concentric city Ring Road network with the Central Business District as the core and center of community and commercial activities, while the Outer Ring road city limits are the location of major residential zones [3]. This study explores how the Analytic Hierarchy Process (AHP) can be combined with spatial modeling for urban CBD flood risk assessment.…”