Abstract: The self-organization phenomena of pedestrian flow through a bottleneck in a channel are investigated by experiments. Different width of bottlenecks and initial distributions are taken into account. Experiments of unidirectional and bidirectional pedestrian flows through bottlenecks are carried out. Typical characteristics of pedestrian flows are observed, such as fan-shaped aggregation in front of the bottleneck, and sidling through the narrow bottleneck and oscillatory flows. These are formed because of the pedestrian behaviors i.e., following other people walking in the same direction and avoiding conflicts with those in an opposite direction. Similarities and differences between unidirectional and bidirectional pedestrian flows are discussed in the following aspects: coordination of pedestrians, flow and specific flow. It is found that the flow increases with the width of bottleneck in both cases. The specific flow in the bidirectional case deceases monotonously with the width of bottleneck. However, the specific flow in the unidirectional case decreases first, and then increases. When the width of the bottleneck is less than the shoulder-width, the unidirectional pedestrian flow is more efficient. However, the efficiency of walking in the case of bidirectional flows is higher than unidirectional flows when the bottleneck width is slightly larger than the shoulder-width.

Key words: bidirectional flow, bottleneck, pedestrian flow, unidirectional flow