  Understanding on children's movement characteristics is significant to
improve their safety levels especially under emergencies. In this work, we
performed laboratory experiment to investigate the dynamics of preschool
children passing through bottlenecks under high movement motivation. It is
found that the relations between flow and bottleneck width for adults and
children can be unified when the body size and movement motivation are
considered in certain way. High movement motivation leads to competition among
pedestrians, which results in different spatial-temporal distribution of the
density and speed compared to normal movement of adult. Based on Voronoi
method, an arch-like distribution is observed for the children movement with
competition, whereas it is teardrop-shaped for the adults without competition.
The peak density of children, which reaches nearly 14 ped/m2, appears at the
place 30 cm away from the bottleneck entrance. However, it is about 100 cm to
the bottleneck for adults. Besides, several typical behaviors of children like
guiding, pushing as well as playing are observed in the experiment. The
findings in this study will benefit the evacuation drill design as well as the
facility design for children.
