Figure 1.
Observed group size distribution in populations A and B.
The light grey curve indicates the zero-truncated Poisson fit () with
and
for populations A and B, respectively.
Figure 2.
Effects of group size on walking speed.
Average walking speed as a function of group size at low density (light grey) and moderate density (dark grey). Error bars indicate the standard error of the mean value. The fit curves are y = −0.04x+1.26 for population A and y = −0.08x+1.24 for population B.
Figure 3.
Illustration of the measurement method.
We define and dij as the angle and distance between pedestrians i and j, where i and j belong to the same group and j is i's closest neighbour on the right-hand side.
Figure 4.
Average patterns of organization.
The positions of pedestrians are reconstructed from the empirical angle and distance values provided in table 1 (dark grey), and from simulation results (light grey). The best fit parameters were obtained through a calibration process and amount to = 4;
= 3;
= 1; do = 0.8 m;
= 90°.
Table 1.
Average angle and distance values between group members for each group size and density level.
Figure 5.
Illustration of the model variables.
a) is the gazing direction vector of pedestrian i. The dashed lines represent the borders of the visual field. b) Pedestrian i rotates his head direction by an angle
, so that the focus point ci is included in the vision field.
Figure 6.
Simulation results for pedestrian groups with and without communication-enhancing interactions.
(a) Speed-density curves showing the impact of group organization on traffic efficiency. For = 0, group members are attracted by the group's centre of mass only letting them stay together. This creates an inverse V-shaped configuration. For
= 4, the value determined from our empirical observations, group members adapt their position to see the other group members, creating a V-shaped configuration. The dashed curve corresponds to simulations with isolated pedestrians only (no groups). (b) Illustration of typical group patterns for
= 0 and
= 4 at a density of 0.25 ped/m2. The simulation parameters are the same as in figure 4.