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AKSOE: Physik sozio-ökonomischer Systeme

AKSOE 3: Postersitzung

AKSOE 3.16: Poster

Montag, 24. März 2003, 15:45–17:15, P1

Spatiotemporal States of Congested Traffic - an Empirical Investigation — •Martin Schönhof, Martin Treiber, and Dirk Helbing — Institut für Wirtschaft und Verkehr, TU Dresden

We present a new method to obtain spatio-temporal information from aggregated data of stationary traffic detectors, the “adaptive smoothing method”. In essential, a nonlinear spatio-temporal lowpass filter is applied to the input detector data. This filter exploits the fact that, in congested traffic, perturbations travel upstream at a near-constant speed, while in free traffic, information propagates downstream. As a result, one obtains velocity, flow, or other traffic variables as smooth functions of space and time.

We applied the method to traffic data on several German freeways. All of the about 400 observed congestions were composed of one or more of the following characteristic spatio-temporal structures: Oscillating and homogeneous congested traffic, moving and pinned localized clusters, and triggered stop-and go waves. More than 90% of all congestions occurred at bottlenecks, mostly intersections. For some bottlenecks, we plotted each congestion as a point in a plane spanned by the traffic flow and by a No-dqgeneralized bottleneck strengthNo-dq and found a certain concentration of each of the five spatiotemporal states in different regions in this No-dqphase diagramNo-dq. All this is in remarkable agreement with theoretical predictions from microscopic and macroscopic traffic models.