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The risks of group trampling during escalator transfers were studied in this paper. A state shifting model was proposed to describe the behaviors of a pedestrian during a group trampling accident. Based on the model, a group trample during escalator transfers was simulated from the beginning of the accident to the transfer recovery using the social force model. The impacts of 6 key factors were studied including the initial location of the accident, the time taken to invoke emergency measures, pedestrian velocity, escalator velocity, time taken for a fallen pedestrian to stand up, and pedestrian traffic. The results show that (1) when an accident happens in the transfer aisle, the peak number of pinned pedestrians is higher, while when it occurs near an escalator exit, the pressure exerted on the pinned pedestrians is more serious; (2) the speed of propagation of the accident is always faster than the recovery rate, and the earlier the emergency measures are taken, the less serious the accident is; (3) overall, except for the initial location of a trampling accident, which cannot be controlled, the other five factors have positive correlations with the severity of a group trampling accident, and can be descending ordered by their impacts using a regression analysis: early measures, pedestrian traffic, short standing-up delay, pedestrian velocity, and escalator velocity. These results can be referenced in the development of countermeasures to reduce group trampling risks. [ABSTRACT FROM AUTHOR]

The congestion risk during escalator transfers was simulated based on a modified social force model. A four-stage transfer model was proposed. A projection strategy was employed to calculate the social forces for inclined surfaces, and a schedule-line model was proposed to calculate the targets adaptively. Realistic simulations of escalator transfer activities were achieved. The results demonstrate that the spatial distribution of the congestion risks is inhomogeneous. A few areas contain clearly higher risks, and the congestion risk is higher in the transfer aisles than on the escalators. The congestion risk in the transfer aisle is influenced more by the average pedestrian speed than that of the escalators. Slower walkers in the transfer aisle may cause congestion, which is more serious when the escalator speed is faster than that of the pedestrians. Therefore, to reduce the congestion risk, the speed of the escalator should be set slower than the average speed of the pedestrians, and conductors can be employed to divert the traffic at the entrance, turns, and exit of the escalator. [ABSTRACT FROM AUTHOR]

Abstract: A type of trampling process that is caused by picking-up activities during escalator transfers was studied in this paper. A five-stage trampling model for individual pedestrians was proposed, and the social force model was modified considering the transfer features. Several scenarios were simulated to study the impacts of 4 factors, namely, pedestrian traffic, escalator velocity, picking-up duration and pedestrian velocity, on trampling probability. The results show that pedestrian traffic strongly affects the trampling probability, with a positive correlation throughout all scenarios; the picking-up duration affects the trampling probability, with a negative correlation throughout all scenarios; lower pedestrian velocities can result in higher trampling probabilities if the picking-up duration is short; and the escalator velocity may also affect the trampling probability, but there are no general rules for all scenarios. Thus, the impacts of these 4 factors can be queued in descending order as follows: pedestrian traffic picking-up duration pedestrian velocity escalator velocity. Countermeasures can be employed according to the results to reduce trampling risks. [Copyright &y& Elsevier]

In order to study the crowd evacuation process in complex subway stations, this paper proposes a social group perception evacuation model based on the social group evacuation model and the perception evacuation model, combined with the spatial index algorithm and the social group random algorithm, and takes a real subway station as an example to simulate the crowd evacuation process. Through the simulation results, the evacuation bottlenecks in the subway station are analyzed and the influence of social groups on evacuation efficiency is also verified. The results show that subway gates, fenced aisles and exits are important bottlenecks for crowd evacuation in subway stations, and the social groups will reduce the evacuation efficiency. This model can more truly restore the interaction behavior between evacuees and the environment in the evacuation process, and is suitable for the real complex subway stations. • Bottlenecks that affecting evacuation efficiency in subway stations mainly include subway gates, fenced aisles and exits. • Social groups have an important effect on evacuation efficiency. • The variation trends of panic index of individuals and social groups under different desired velocities are basically the same. [ABSTRACT FROM AUTHOR]

Few studies have focused on the evacuation of multi-floor classroom buildings in a primary school, a process that differs from evacuations in other buildings. A stair-unit model was proposed to describe the spatial topology of twisting stairwells and to describe the spatial relationship between stairwells and floors. Based on the stair-unit model, a schedule-line model was proposed to calculate evacuation paths in stair-units; a modified algorithm to calculate pedestrian forces were proposed to describe the evacuee movements in stairwells; and a projection strategy was proposed to model the 3-dimensional evacuation process in multi-floor buildings. The simulated processes were compared with a real evacuation drill. The results showed that the simulated process achieved qualitative and quantitative consistencies with the real drill, proving the appropriateness of the proposed models and algorithms. Based on the validation, further simulations were conducted and a few rules for evacuations in stairwells were identified including rules governing the impact of the moment of entering a staircase, the number of students in a class, the stagger strategy, and the layout of grades on different floors on the time in stairwell and the total evacuation duration. The results can be used to mitigate the effects of a fire disaster, and the proposed models and algorithms can also be referenced by evacuation simulation for other multi-floor buildings such as residential buildings. [ABSTRACT FROM AUTHOR]

Orderly queuing behavior in open areas with bending effects is studied in this paper. Models are proposed to simulate such behavior, including a motion state model, bending effect model, leader–follower model, virtual linear obstacle model, and group-shopping model. By comparing a simulated queue with an actual one, the entire processes of a pedestrian walking to a queue tail, joining the queue, orderly moving in the queue, shopping, and leaving the queue can be simulated. Additionally, the "arc bending" effect with one or multiple obstacles, the "stop-and-go" behavior and its backward propagation along the queue, and the "group shopping" effect around the shopping point are reproduced, similarly to the behavior observed in actual queues. Moreover, factors affecting queuing efficiency are studied, including the minimum distance between leaders and followers, the shopping duration and its randomness, the time interval for a new pedestrian to appear, and the size of pedestrian groups. Compared with the other factors, shopping duration is the most critical factor. Therefore, measures to shorten shopping duration should be taken to improve queuing efficiency. • A model for orderly queuing behavior with bending effects is proposed. • The "arc bending" effect when encountering an obstacle is reproduced. • The "stop-and-go" behavior and its backward propagation are reproduced. • The "group shopping" behavior is reproduced. • Shopping duration is a critical factor affecting queuing efficiency. [ABSTRACT FROM AUTHOR]