3,558 research outputs found
Pedestrian Flow Characteristics at Upstream and Downstream of Bottleneck for Unidirectional Flow under Normal Conditions
The study of pedestrian flow characteristics at upstream and downstream of bottlenecks is important from level of service and evacuation perspective. Many controlled laboratory experiments have been conducted to study pedestrians’ behavior at bottlenecks. However, it is unclear whether experiments can reproduce real crowd flow characteristics. In this paper, real field data was collected at normal conditions for unidirectional pedestrian movement at Mahakaleshwar, a Hindu temple at Ujjain, India during Mahashivaratri, a festival day on which a large number of pilgrims visited the temple. Along the corridor there is a width reduction at a U-turn which creates a bottleneck. It is necessary to study pedestrian flow characteristics at bottlenecks to ensure desired level of service at temple premises during heavy flow. The speed-density relationships of upstream and downstream sections were compared and it was found that flow behavior at both the sections of bottleneck severely differ from each other. Pedestrians in the upstream are either at free flow speed for very low density values or moving slowly for intermediate to high range of density values. From the speed-density relationship, it can be concluded that pedestrians at upstream had visual clues of congestion ahead at bottleneck (pedestrian could also see the downstream flow through barricades). Therefore, pedestrians wait at their position, stay in their comfort zone and do not push each other. Thus, even at intermediate local density, pedestrians have such low speeds. This violates the general assumption that pedestrians change their speed only at the shockwave boundary. The movement of pedestrians at upstream is governed by local density and information of congestion status ahead, whereas pedestrian movement at downstream is governed by factors like density, side friction and pedestrians’ willingness to compensate for the delay at bottleneck. This study is expected to have application in planning and operation of pedestrian facilities
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 which show considerable differences with respect to the
estimated flow values. Moreover do new experimental data indicate a stepwise
growing of the capacity with the width and thus challenge the validity of the
specific flow concept. To resolve these differences we have studied
experimentally the unidirectional pedestrian flow through bottlenecks under
laboratory conditions. The time development of quantities like individual
velocities, density and individual time gaps in bottlenecks of different width
is presented. The data show a linear growth of the flow with the width. The
comparison of the results with experimental data of other authors indicates
that the basic assumption of the capacity estimation for bottlenecks has to be
revised. In contradiction with 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 of the flow according to the fundamental diagram.Comment: Traffic flow, pedestrian traffic, crowd dynamics, capacity of
bottlenecks (16 pages, 8 figures); (+ 3 new figures and minor revisions
Experimental study of pedestrian flow through a bottleneck
In this work the results of a bottleneck experiment with pedestrians are
presented in the form of total times, fluxes, specific fluxes, and time gaps. A
main aim was to find the dependence of these values from the bottleneck width.
The results show a linear decline of the specific flux with increasing width as
long as only one person at a time can pass, and a constant value for larger
bottleneck widths. Differences between small (one person at a time) and wide
bottlenecks (two persons at a time) were also found in the distribution of time
gaps.Comment: accepted for publication in J. Stat. Mec
Microscopic insights into pedestrian motion through a bottleneck, resolving spatial and temporal variations
The motion of pedestrians is subject to a wide range of influences and
exhibits a rich phenomenology. To enable precise measurement of the density and
velocity we use an alternative definition using Voronoi diagrams which exhibits
smaller fluctuations than the standard definitions. This method permits
examination on scales smaller than the pedestrians. We use this method to
investigate the spatial and temporal variation of the observables at
bottlenecks. Experiments were performed with 180 test subjects and a wide range
of bottleneck parameters. The anomalous flow through short bottlenecks and
non-stationary states present with narrow bottlenecks are analysed
Pedestrian, Crowd, and Evacuation Dynamics
This contribution describes efforts to model the behavior of individual
pedestrians and their interactions in crowds, which generate certain kinds of
self-organized patterns of motion. Moreover, this article focusses on the
dynamics of crowds in panic or evacuation situations, methods to optimize
building designs for egress, and factors potentially causing the breakdown of
orderly motion.Comment: This is a review paper. For related work see http://www.soms.ethz.c
Generalized Centrifugal Force Model for Pedestrian Dynamics
A spatially continuous force-based model for simulating pedestrian dynamics
is introduced which includes an elliptical volume exclusion of pedestrians. We
discuss the phenomena of oscillations and overlapping which occur for certain
choices of the forces. The main intention of this work is the quantitative
description of pedestrian movement in several geometries. Measurements of the
fundamental diagram in narrow and wide corridors are performed. The results of
the proposed model show good agreement with empirical data obtained in
controlled experiments.Comment: 10 pages, 14 figures, accepted for publication as a Regular Article
in Physical Review E. This version contains minor change
Steady State of Pedestrian Flow in Bottleneck Experiments
Experiments with pedestrians could depend strongly on initial conditions.
Comparisons of the results of such experiments require to distinguish carefully
between transient state and steady state. In this work, a feasible algorithm -
Cumulative Sum Control Chart - is proposed and improved to automatically detect
steady states from density and speed time series of bottleneck experiments. The
threshold of the detection parameter in the algorithm is calibrated using an
autoregressive model. Comparing the detected steady states with previous
manually selected ones, the modified algorithm gives more reproducible results.
For the applications, three groups of bottleneck experiments are analysed and
the steady states are detected. The study about pedestrian flow shows that the
difference between the flows in all states and in steady state mainly depends
on the ratio of pedestrian number to bottleneck width. When the ratio is higher
than a critical value (approximately 115 persons/m), the flow in all states is
almost identical with the flow in steady state. Thus we have more possibilities
to compare the flows from different experiments, especially when the detection
of steady states is difficult.Comment: 19 pages, 7 figure
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