Experiment, theory, and simulation of the evacuation of a room without visibility.

We study the evacuation process from a smoky room by means of experiments and simulations. People in a dark or smoky room are mimicked by "blind" students wearing eye masks. The evacuation of the disoriented students from the room is observed by video cameras, and the escape time of each student is measured. We find that the disoriented students exhibit a distinctly different behavior compared to a situation in which people can see their environment. Our experimental results are related to a theoretical approach and reproduced by an extended lattice gas model taking into account the empirically observed behavior. Our particular focus is on the mean value and distribution of escape times. For a large number of people in the room, the escape time distribution is wide because of jamming. Surprisingly, adding more exits does not improve the situation in the expected way, since most people use the exit that is discovered first, which may be viewed as a kind of herding effect based on nonlocal, but direct acoustic interactions. Moreover, the average escape time becomes minimal for a certain finite number of people in the dark or smoky room. These nonlinear effects have practical implications for emergency evacuation and the planning of safer buildings.

Lattice gas simulation of experimentally studied evacuation dynamics.

We study the evacuation process from a classroom by means of experiments and simulations. The evacuation of students from a classroom is observed by video cameras, and the escape time of each student is measured. Our experimental results are compared with simulations based on a lattice gas model of pedestrian flows. We find that the empirically identified inefficiencies of the evacuation process can be well reproduced. Our particular focus is on the spatial dependence of the escape times on the initial positions, which is highly significant. The escape time distribution turns out to be rather broad due to a jamming (queuing) of the students at the exit, which determines not only the saturation flow (capacity) but also the temporal characteristics of the evacuation dynamics.