Social groups barely change the speed-density relationship in unidirectional pedestrian flow, but affect operational behaviours

Hu, Yanghui; Zhang, Jun; Song, Weiguo; Bode, Nikolai W. F.

doi:10.1016/j.ssci.2021.105259

Cited by 26 publications

(13 citation statements)

References 37 publications

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“…At the operational level, 'microscopic' (agent-based) models could help rationalise the seemingly conflictual effects of social groups on the flow properties observed experimentally (Von Krüchten et al, 2017;Crociani et al, 2017b;Hu et al, 2021) by pinpointing the mechanisms at the origin of the observed trends. Moreover, they make it possible to explore scenarios beyond the ones that can (safely) be tested experimentally.…”

Section: Discussionmentioning

confidence: 99%

“…2), small groups may have only little impact on the fundamental diagram, at least at medium to high densities (higher than 1 ped/m²). Indeed, the latest experiments by (Hu et al, 2021) found that, at densities between 1.25 and 4 ped/m², crowds made of individuals ('atomic') did not flow considerably faster than crowds made of dyads, with the difference between the two situations hardly visible in the midst of the experimental variability. In fact, atomic crowds even seemed to display a slightly more pronounced slowdown as the density increased, possibly owing to the higher capacity of groups to adapt their configuration.…”

Section: A Unidirectional Flowsmentioning

confidence: 99%

“…At the 'microscopic' level, it was empirically found that, far from being amorphous aggregates, social groups of pedestrians tend to adopt particular shapes (Moussaid et al, 2010) and to move slower than single pedestrians. At the collective scale, the impact of these groups on major flow properties -in particular on the fundamental diagram that relates the pedestrian density and the flow rate (Hu et al, 2021) and on evacuation times in the event of an emergency (Ma et al, 2017;Li et al, 2020) has also received considerable attention, but the observed effects are either less marked or more controversial. These questions are however of paramount importance to properly dimension facilities with different types of crowd compositions or to estimate evacuation times of crowded rooms, and have recently seeped into new scientific areas in the context of the Covid-19 pandemic, which prompted physical distancing guidelines (Pouw et al, 2020;Garcia et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Social groups in pedestrian crowds: review of their influence on the dynamics and their modelling

Nicolas

Hafinaz

2021

Transportmetrica A: Transport Science

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Pedestrians are often encountered walking in the company of some social relations, rather than alone. The social groups thus formed, in variable proportions depending on the context, are not randomly organised but exhibit distinct features, such as the well-known tendency of 3-member groups to be arranged in a V-shape. The existence of group structures is thus likely to impact the collective dynamics of the crowd, possibly in a critical way when emergency situations are considered. After turning a blind eye to these group aspects for years, endeavours to model groups in crowd simulation software have thrived in the past decades. This fairly short review opens on a description of their empirical characteristics and their impact on the global flow. Then, it aims to offer a pedagogical discussion of the main strategies to model such groups, within different types of models, in order to provide guidance for prospective modellers.

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Section: Discussionmentioning

confidence: 99%

Section: A Unidirectional Flowsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Social groups in pedestrian crowds: review of their influence on the dynamics and their modelling

Nicolas

Hafinaz

2021

Transportmetrica A: Transport Science

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“…Groups represent an important component of pedestrian crowds 1 , 2 , and lately they have been the subject of many studies, focusing on such themes as their effect on crowd dynamics 3 , the observation of their shape and velocity 1 , 4 – 9 , mathematical and computational modeling of interaction dynamics 5 , 10 – 15 , and dependence on social structure and interaction level 16 – 19 . Many works are based on ecological observations 1 , 4 – 6 , 12 , 16 – 21 , which may be argued to be indispensable in dealing with social aspects of human behavior 4 , 22 – 27 .…”

Section: Introductionmentioning

confidence: 99%

Social aspects of collision avoidance: a detailed analysis of two-person groups and individual pedestrians

Gregorj

Yücel

Zanlungo

et al. 2023

Sci Rep

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Pedestrian groups are commonly found in crowds but research on their social aspects is comparatively lacking. To fill that void in literature, we study the dynamics of collision avoidance between pedestrian groups (in particular dyads) and individual pedestrians in an ecological environment, focusing in particular on (i) how such avoidance depends on the group’s social relation (e.g. colleagues, couples, friends or families) and (ii) its intensity of social interaction (indicated by conversation, gaze exchange, gestures etc). By analyzing relative collision avoidance in the “center of mass” frame, we were able to quantify how much groups and individuals avoid each other with respect to the aforementioned properties of the group. A mathematical representation using a potential energy function is proposed to model avoidance and it is shown to provide a fair approximation to the empirical observations. We also studied the probability that the individuals disrupt the group by “passing through it” (termed as intrusion). We analyzed the dependence of the parameters of the avoidance model and of the probability of intrusion on groups’ social relation and intensity of interaction. We confirmed that the stronger social bonding or interaction intensity is, the more prominent collision avoidance turns out. We also confirmed that the probability of intrusion is a decreasing function of interaction intensity and strength of social bonding. Our results suggest that such variability should be accounted for in models and crowd management in general. Namely, public spaces with strongly bonded groups (e.g. a family-oriented amusement park) may require a different approach compared to public spaces with loosely bonded groups (e.g. a business-oriented trade fair).

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“…Groups represent an important component of pedestrian crowds 1,2 , and lately they have been the subject of many studies, focusing on such themes as their effect on crowd dynamics 3 , the observation of their shape and velocity 1,[4][5][6][7][8][9][10][11] , mathematical and computational modeling of interaction dynamics 6,[12][13][14][15][16][17] , and dependence on social structure and interaction level [18][19][20][21][22] . Many works are based on ecological observations 1, 5-7, 14, 19-23, 23-27 , which may be argued to be indispensable in dealing with social aspects of human behavior 5,[28][29][30][31][32][33] .…”

Section: Introductionmentioning

confidence: 99%

Social aspects of collision avoidance: A detailed analysis of groups and individual pedestrians

Gregorj

Yücel

Zanlungo

et al. 2023

Preprint

View full text Add to dashboard Cite

Pedestrian groups are commonly found in crowds but research on their social aspects is comparatively lacking. To fill that void in literature, we study the dynamics of collision avoidance between pedestrian groups (in particular dyads) and individual pedestrians in an ecological environment, focusing in particular on (i) how such avoidance depends on the group's social relation (e.g. colleagues, couples, friends or families) and (ii) its intensity of social interaction (indicated by conversation, gaze exchange, gestures etc). By analyzing relative collision avoidance in the "center of mass" frame, we were able to quantify how much groups and individuals avoid each other with respect to the aforementioned properties of the group. A mathematical representation using a potential energy function is proposed to model avoidance and it is shown to provide a fair approximation to the empirical observations. We also studied the probability that the individuals disrupt the group by "passing through it" (termed as intrusion). We analyzed the dependence of the parameters of the avoidance model and of the probability of intrusion on groups' social relation and intensity of interaction. We confirmed that the stronger social bonding or interaction intensity is, the more prominent collision avoidance turns out. We also confirmed that the probability of intrusion is a decreasing function of interaction intensity and strength of social bonding. Our results suggest that such variability should be accounted for in models and crowd management in general. Namely, public spaces with strongly bonded groups (e.g. a family-oriented amusement park) require a different approach compared to public spaces with loosely bonded groups (e.g. a business-oriented trade fair).

show abstract

Social groups barely change the speed-density relationship in unidirectional pedestrian flow, but affect operational behaviours

Cited by 26 publications

References 37 publications

Social groups in pedestrian crowds: review of their influence on the dynamics and their modelling

Social groups in pedestrian crowds: review of their influence on the dynamics and their modelling

Social aspects of collision avoidance: a detailed analysis of two-person groups and individual pedestrians

Social aspects of collision avoidance: A detailed analysis of groups and individual pedestrians

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