Pedestrian density and shockwave characteristics just upstream from a bottleneck are described, emphasising a comparison of actual flow characteristics to common modelling assumptions. Results are described through: (1) plots of density, flow, and speed over time; (2) a density and speed contour map of the study site, showing forward- and backward-forming shockwaves; and (3) plots of speed vs density, flow vs density, and speed vs flow. The study site and pedestrian demand violated simplifying assumptions on demand and capacity often used to model bottlenecks. Pedestrians' behaviour violated another common assumption used in traffic analysis - that individuals do not anticipate visible changes in downstream do not anticipate visible changes in downstream conditions and therefore change their speeds only at shockwave boundaries. The data clearly indicate that pedestrians anticipated downstream conditions both when the queue was forming and while the queue was dissipating. (A)
Samenvatting