Effect of form of obstacle on speed of crowd evacuation

Yano, Ryosuke

doi:10.1103/physreve.97.032319

Cited by 37 publications

(21 citation statements)

References 67 publications

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“…Furthermore, decreasing pressure is thought to favour the conflict solution of pedestrians coinciding at the exit and competing for the same space; so that clogging can be minimized. Indeed, the improvement of bottleneck flow by placement of obstacles is being reproduced by most of the recently proposed models of pedestrian dynamics [23][24][25][26][27][28]. In addition, the beneficial role of the obstacle in clogging prevention has been taken as a genuine feature of many-particle systems passing through constrictions.…”

Section: Introductionmentioning

confidence: 99%

Redefining the role of obstacles in pedestrian evacuation

Garcimartín

Maza

Pastor³

et al. 2018

New J. Phys.

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The placement of obstacles in front of doors is believed to be an effective strategy to increase the flow of pedestrians, hence improving the evacuation process. Since it was first suggested, this counterintuitive feature is considered a hallmark of pedestrian flows through bottlenecks. Indeed, despite the little experimental evidence, the placement of an obstacle has been hailed as the panacea for solving evacuation problems. In this work, we challenge this idea and experimentally demonstrate that the pedestrians flow rate is not necessarily altered by the presence of an obstacle. This result-which is at odds with recent demonstrations on its suitability for the cases of granular media, sheep and micediffers from the outcomes of most of existing numerical models, and warns about the risks of carelessly extrapolating animal behaviour to humans. Our experimental findings also reveal an unnoticed phenomenon in relation with the crowd movement in front of the exit: in competitive evacuations, an obstacle attenuates the development of collective transversal rushes, which are hazardous as they might cause falls.

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Section: Introductionmentioning

confidence: 99%

Redefining the role of obstacles in pedestrian evacuation

Garcimartín

Maza

Pastor³

et al. 2018

New J. Phys.

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“…An extra dimension that could to be recognised is the individual variation (or heterogeneity) in strategy choosing that also could be subjected to tests of optimality using numerical analyses [79][80][81]. This stream of behavioural optimisation studies can be regarded as a complementary domain to that of the architectural optimisations that seek to facilitate evacuations through physical modifications of the environment (as opposed to the behaviour of evacuees) [82][83][84][85] or the approach of route-planning optimisations [67,[86][87][88][89][90][91][92][93][94].…”

Section: Summary Discussion and Future Researchmentioning

confidence: 99%

‘Rationality’ in Collective Escape Behaviour: Identifying Reference Points of Measurement at Micro and Macro Levels

Haghani

Sarvi

2019

Journal of Advanced Transportation

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Background. Evacuation behaviour of human crowds is often characterised by the notion of ‘irrational behaviour’. While the term has been frequently used in the literature, clear definitions and methods for measuring rationality do not exist. Objective. Here, we suggest that rationality, in this context, can alternatively and more effectively be formulated as a question of ‘optimal behaviour’. Decision optimality can potentially be measured and quantified. The main challenges, however, include (i) distinctly identifying the level at which we measure optimality, and (ii) identifying proper reference points at each level. Methods. We differentiate between optimality at the individual (i.e., micro) and the system (i.e., macro/aggregate) levels and illustrate how certain reference points can be established at each level. We suggest that, at the micro level, optimality of individual decisions can be quantified by comparing the outcome of each individual’s decision to those of their ‘nearly equal peers’. At the macro level, optimality can be measured by simulating the system using parametric numerical models and measuring the system performance while altering the behavioural parameters compared to their empirical estimates. Results. Having applied these methods, we observed that variation in micro level decision optimality rises rapidly as the space becomes more heavily crowded. As crowdedness increases in the environment, the difference between ‘good’ and ‘bad’ decisions becomes more distinct; and suboptimal decisions become more frequent. In other words, optimality at individual level seems to be moderated by the level of crowdedness. At the macro level, numerical simulations showed that, for certain exit attributes (like exit congestion), extreme marginal valuations (or preferences) were optimal, whereas for certain other attributes (like exit visibility), intermediate levels of valuation were closer to the optimal. In most cases, the natural observed (or estimated) tendency of evacuees (at the aggregate level) was not quite at the optimum level, meaning that the system could improve by modifying individuals’ marginal valuations of exit attributes. Applications and Recommendations. These results highlight the importance of guiding evacuation decisions particularly in heavily crowded spaces. They also theoretically illustrate the potential benefit of influencing/modifying people’s evacuation strategies, so they make decisions that are collectively more efficient. A crucial step to this end, however, is to identify what optimum strategy is and under what circumstances people are likelier to make suboptimal decisions.

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“…This a priori counter-intuitive behavior, was originally proposed to improve pedestrian evacuation from a room with a small exit 1 . After this work, the increment of the flow rate by suitably placing an obstacle in front of the gate has been taken as a hallmark of pedestrian dynamics and, accordingly, it has been reproduced by most of the recently proposed models [2][3][4][5][6][7][8] . Nevertheless, a robust experimental demonstration of the obstacle effectiveness in pedestrian dynamics is still lacking given that the existing results are contradictory [9][10][11][12][13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

On the dual effect of obstacles in preventing silo clogging

Gella

Yanagisawa

Caitano

et al. 2021

Preprint

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We experimentally demonstrate that an obstacle, when suitably placed above a bottleneck, leads to a reduction of clog formation in a silo via two different mechanisms. The first one, already suggested in previous works, is related to an alteration of the kinematic properties in the outlet proximities that prevents the stabilization of arches. The second, that is discovered when working at a quasi-static regime, appears because the obstacle induces a clear anisotropy in the contact fabric tensor. Then, both mechanisms are encompassed using a single equation in which two parameters -one related with the geometrical effects and the other to the kinematic ones- are enough to reproduce all the experimental results

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Effect of form of obstacle on speed of crowd evacuation

Cited by 37 publications

References 67 publications

Redefining the role of obstacles in pedestrian evacuation

Redefining the role of obstacles in pedestrian evacuation

‘Rationality’ in Collective Escape Behaviour: Identifying Reference Points of Measurement at Micro and Macro Levels

On the dual effect of obstacles in preventing silo clogging

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