Impact on pedestrian flow of bends in passenger access tunnels

With the constant increase of underground railway passenger volumes, congestion in pedestrian access tunnels is a growing concern. In conventional access tunnel design, pedestrian flow and capacity are the main factors considered. However, the microscopic characteristics of pedestrian flow, which are critical to passenger safety and traffic efficiency, have tended to be neglected in the engineering design and construction process. The paper reports on an investigation into the impact of geometric design of access tunnel bends on pedestrian flows. Controlled pedestrian experiments on different combinations of bend angles, radii and pedestrian volumes were conducted. It was found that the characteristics of pedestrian flow vary with different angles and radii, with angle being the most significant factor. When the angle is 90°, which is a common configuration in Beijing's subway system, the cumulative density and average speed are largely affected by the radius and volume. Findings in this study provide theoretical support to the design and renovation of subway corridors in practice.