Mode-Dependent optimal positioning of evacuation Guides: An Experimental–Modeling study on static and dynamic guidance effect

The guides can help pedestrians find exits, thereby improving evacuation efficiency and reducing casualties in emergency. This study investigates how guides affect crowd evacuations via controlled experiments and modeling. To investigate the influence of guide on crowd evacuation, a Social Force Model with Guidance (SFMG) has been established by embedding the guidance term into the social force framework. The interaction mechanism between a guide and pedestrians was studied by performing crowd movement experiments under different guidance modes (dynamic/static), movement speeds and crowd densities. The guidance attraction force formula involving the above variables has been proposed. It is revealed that the guidance attraction field is influenced by the guidance mode and speed. Subsequently, the simulations in a subway platform under varying visibility conditions were conducted and the influence of the initial layout of guides on crowd evacuation efficiency was studied. The results revealed that arranging guides in the areas far from the exit can facilitate the crowd evacuation. The distance between the guide’s initial position and exit was denoted as D. in the simulation analyses. A variable DR (distance ratio) calculated by the ratio of D to the length of the platform subzone was adopted to quantity guide’s initial position. Dynamic guide: The higher DR results in the shorter evacuation time under low visibility. But the optimal initial position of guide shifts slightly closer to the exit with increasing visibility. Static guide: The U-shaped relationship between evacuation time and DR is observed. The optimal position falls within the 40 %∼60 % DR . These findings are helpful to design indoor emergency guidance plan, and the optimal positioning rules are transferable to common building layouts.