Wolfram Klingsch

New Insights into Pedestrian Flow Through Bottlenecks

Capacity estimation is an important tool for the design and dimensioning of pedestrian facilities. The literature contains different procedures and specifications that show considerable differences with respect to the estimated flow values. Moreover, new experimental data indicate a stepwise growth of capacity with width and thus challenge the validity of the specific flow concept. To resolve these differences, we experimentally studied the unidirectional pedestrian flow through bottlenecks under laboratory conditions. The time development of quantities such as individual velocities, density, and individual time gaps in bottlenecks of different widths is presented. The data show a linear growth of flow with width. The comparison of the results with experimental data from other authors indicates that the basic assumption of the capacity estimation for bottlenecks has to be revised. In contrast to most planning guidelines, our main result is that a jam occurs even if the incoming flow does not overstep the capacity defined by the maximum flow according to the fundamental diagram.

Transitions in pedestrian fundamental diagrams of straight corridors and T-junctions

Many observations of pedestrian dynamics, including various self-organization phenomena, have been reproduced successfully by different models. But the empirical databases for quantitative calibration are still insufficient, e.g.?the fundamental diagram as one of the most important relationships displays non-negligible differences among various studies. To improve this situation, experiments in straight corridors and T-junctions are performed. Four different measurement methods are defined to study their effects on the fundamental diagram. It is shown that they have minor influences for ? < 3.5?m?2 but only the Voronoi method is able to resolve the fine structure of the fundamental diagram. This enhanced measurement method permits us to observe the occurrence of a boundary-induced phase transition. For corridors of different widths we found that the specific flow concept works well for ? < 3.5?m?2. Moreover, we illustrate the discrepancies between the fundamental diagrams of a T-junction and a straight corridor.

Ordering in bidirectional pedestrian flows and its influence on the fundamental diagram

Experiments under laboratory conditions were carried out to study the ordering in bidirectional pedestrian streams and its influence on the fundamental diagram (density–speed–flow relation). The Voronoi method is used to resolve the fine structure of the resulting velocity–density relations and spatial dependence of the measurements. The data show that the specific flow concept is applicable also for bidirectional streams. For various forms of ordering in bidirectional streams, no large differences among density–flow relationships are found in the observed density range. The fundamental diagrams of bidirectional streams with different forms of ordering are compared with those of unidirectional streams. The result shows differences in the shape of the relation for ρ > 1.0 m − 2. The maximum of the specific flow in unidirectional streams is significantly larger than that in all bidirectional streams examined.

Enhanced Empirical Data for the Fundamental Diagram and the Flow Through Bottlenecks

In recent years, several approaches for modeling pedestrian dynamics have been proposed and applied e.g. for design of egress routes. However, so far not much attention has been paid to their quantitative validation. This unsatisfactory situation belongs amongst others on the uncertain and contradictory experimental data base. The fundamental diagram, i.e. the density-dependence of the flow or velocity, is probably the most important relation as it connects the basic parameter to describe the dynamic of crowds. But specifications in different handbooks as well as experimental measurements differ considerably. The same is true for the bottleneck flow. After a comprehensive review of the experimental data base we give an survey of a research project, including experiments with up to 250 persons performed under well controlled laboratory conditions. The trajectories of each person are measured in high precision to analyze the fundamental diagram and the flow through bottlenecks. The trajectories allow to study how the way of measurement influences the resulting relations. Surprisingly we found large deviation amongst the methods. These may be responsible for the deviation in the literature mentioned above. The results are of particular importance for the comparison of experimental data gained in different contexts and for the validation of models.

Empirical data for pedestrian flow through bottlenecks

The number of models for pedestrian dynamics has grown in the past years, but the experimental data to discriminate between these models is still to a large extent uncertain and contradictory. To enhance the data base and to resolve some discrepancies discussed in the literature over one hundred years we studied the pedestrian flow through bottlenecks by an experiment performed under laboratory conditions. The time development of quantities like individual velocities, densities, individual time gaps in bottlenecks of different width and the jam density in front of the bottleneck is presented. The comparison of the results with experimental data of other authors supports a continuous increase of the capacity with the bottleneck width. The most interesting results of this data collection is that maximal flow values measured at bottlenecks can exceed the maxima of empirical fundamental diagrams significantly. Thus either our knowledge about empirical fundamental diagrams is incomplete or the common assumptions regarding the connection between the fundamental diagram and the flow through bottlenecks need a thorough revision.

Was It Panic? An Overview About Mass-Emergencies and Their Origins All Over the World for Recent Years

Mass-emergencies are very popular in the news, whether we watch news on TV or read a newspaper. In most of these news we are able to read that people were fallen in panic or a mass-panic occured. This is a simple, but often used explanation why people died in such situations. But is that the truth? If we look at selected mass-emergencies like Bergisel-Stadium we can see, that the loss of a shoe was the origin of this phenomenon, where five girls died. One pedestrian lost a shoe while he was walking to the exit. He stopped to put on his shoe, but because of the high density of pedestrians, the other pedestrian were not able to sidestep at this moment, thus they had to stop. The pedestrians behind them did not see the boy putting on his shoe and thus they pressed against the other pedestrians, just for fun. In this case, the phenomenon of behavior was not panic, we will call this crush with very local panic behavior.

Steps Toward the Fundamental Diagram — Empirical Results and Modelling

The empirical relation between density and velocity (fundamental diagram) of pedestrian movement is not completely analyzed, particularly with regard to the ‘microscopic’ causes which determine the relation at medium and high densities. The simplest system for the investigation of this dependency is the single-file movement. We present experimental results for this system and discuss the following observations. The data show a linear relation between the velocity and the inverse of the density, which can be regarded as the required length of one pedestrian to move. Furthermore we compare the results for the single-lane movement with literature data for the movement in a plane. This comparison shows an unexpected conformance between the fundamental diagrams, indicating that lateral interference has negligible influence on the velocity-density relation.

Influence of Geometry Parameters on Pedestrian Flow through Bottleneck

In pedestrian evacuations bottlenecks can be a crucial factor influencing the evacuation time. The main question involves the design of bottlenecks to enable unhindered pedestrian flow in order to optimize evacuation times. For better understanding of this problem, a set of experiments with pedestrians in different bottleneck-scenarios has been performed. The results enlarge the database and allow the testing of the basic assumptions of performance based egress design.

Prediction Accuracy of Evacuation Times for High-Rise Buildings and Simple Geometries by Using Different Software-Tools

Evaluation and optimization of emergency systems can be done by means of several engineering methods, which are entirely different: macroscopic hydraulic models, which can be calculated by hand (so called handcalculation methods), and microscopic computer simulation methods. Both allow forecasting of evacuation-times for various settings. The authors compare results of four commercial software-tools (ASERI, buildingEXODUS, PedGo, Simulex) and some macroscopic handcalculation models with a real evacuation-trial in a high-rise building. Furthermore evacuation times for simple layouts of room and floor are calculated and the results are compared against each other.

The Fundamental Diagram of Pedestrian Movement Revisited — Empirical Results and Modelling

The simplest system for the investigation of the fundamental diagram for pedestrians is the single-file movement. We present experimental results for this system and discuss the observed linear relation between the velocity and the inverse of the density. For the modelling we treat pedestrians as self-driven objects moving in a continuous space. On the basis of a modified social force model we analyze qualitatively the influence of various approaches for the interactions of pedestrians on the resulting velocity-density relation. The one-dimensional model allows focusing on the role of the required length and remote force. We found that the reproduction of the typical form of the fundamental diagram is possible if one considers the increase of the required length of a person with increasing current velocity. Furthermore we demonstrate the influence of a remote force on the velocity-density relation.