# A Study on Crowd Evacuation Model Considering Squeezing Equilibrium in Crowded Areas
## 4 Simulation Experiment
### Data Processing Method
In complex scene 4, the number of pedestrians is 101 and the optimized model is still better than the original model when the number of pedestrians is small. Figure 10: Relationship between evacuation time and degree of squeezing in scenario 2: (**a**) Original model; (**b**) Optimize the model. Figure 9: Relationship between evacuation time and degree of squeezing in scenario 1: (**a**) Original model; (**b**) Optimize the model. In a word, the experimental results show that the original model and the optimized model have the same ability to control the probability of exceeding the maximum extrusion range, but the optimized model shows better stability in controlling the intersection without exceeding the maximum extrusion degree. In order to verify the effectiveness of the simulation experiment, actual physical experiments are carried out in combination with the simulation scenario to verify the above conclusions, as shown in Figure 13.  
According to (b) and (c) of Figures 1, 3, 5 and 7, the original model evacuation simulation shows that the pedestrian stagnation phenomenon and the situation of some pedestrians squeezing each other in dense areas occur. Compared with the real evacuation experiment (a), (b) and (c), it is found that the stagnation phenomenon does not occur due to the self-organization effect of pedestrians. It can be seen from (d) that when the density is high, arching will occur without obvious extrusion, which is consistent with (b) and (c) in Figures 2, 4, 6 and 8. Because of the safety problem, it is difficult to carry out the high-density crowd evacuation experiment. From the comparative analysis of the three extrusion probabilities of the original model and the optimized model in Figures 9-11, it can be seen that the probability that the original model intersects and is not greater than the maximum extrusion degree is significantly higher than the optimized model, which is seriously inconsistent with (d). In conclusion, the accuracy of the optimization model in simulating the real evacuation is higher than that of the original model. \[p_{1}(x1)>p_{2}(x1),p_{1}(x2)>p_{2}(x2) \tag{29}\]0 Relationship between evacuation time and degree of squeezing in scenario 3: (**a**) Original model; (**b**) Optimize the model. \[p_{1}(x1)>p_{2}(x1),p_{1}(x2)>p_{2}(x2) \tag{29}\]1 Relationship between evacuation time and degree of squeezing in scenario 4: (**a**) Original model; (**b**) Optimize the model. Then, aiming at the complex scene (scene 1), the influence of the new model on the evacuation time under different squeezing degrees is further verified. Figure 14 compares the overall squeezing of the original model and the optimized model. The squeezing probability is g = p1 + p2, in which the original social force model is set to g1 and the optimized model is set to g2, and the squeezing probability satisfies Formula (27). The original model almost rose linearly during T \(\leq\) 2.3 s, and then maintained a high squeezing state in a wave-like manner. While the optimized model maintained a very low squeezing state (squeezing probability was almost zero) during T \(\leq\) 11 s; at T \(\geq\) 11 s, because of the congestion at the exit the optimized model showed a controllable and moderate upward trend. This suggests that the optimized model has higher controllability and stability, the probability of squeezing is extremely low, and the degree of squeezing can be well controlled. Thus, due to less squeezing, the optimized model can reduce the time of passing through the exit to a large extent. Figure 15 compares the intersection without exceeding the maximum degree of squeezing of the original model and the optimized model, as the original model and the optimized model have the same ability to control the intersection exceeding the maximum degree of squeezing. The squeezing probability is g = p1, in which the original social force model is  
\[p_{1}(x1)>p_{2}(x1),p_{1}(x2)>p_{2}(x2) \tag{29}\]2 Comparison of extrusion probability.