  To explore the pedestrian motion navigation and conflict reaction mechanisms
in practice, we organized a series of circle antipode experiments. In the
experiments, pedestrians are uniformly initialized on the circle and required
to leave for their antipodal positions simultaneously. On the one hand, a
conflicting area is naturally formulated in the central region due to the
converged shortest routes, so the practical conflict avoidance behaviors can be
fully explored. On the other hand, the symmetric experimental conditions of
pedestrians, e.g., symmetric starting points, symmetric destination points, and
symmetric surroundings lay the foundation for further quantitative comparisons
among participants. The pedestrian trajectories in the experiments are
recognized and rotated, and several aspects, e.g., the trajectory space
distribution, route length, travel time, velocity distribution, and
time-series, are investigated. It is found that: (1) Pedestrians prefer the
right-hand side during the experiments; (2) The route length is as the law of
log-normal distribution, the route potential obeys the exponential
distribution, and the travel time is normally distributed as well as the speed;
(3) Taking the short routes unexpectedly cost pedestrians plenty of travel
time, while detour seems to be a time-saving decision. What's more, the series
of experiments can be regarded as a basis of the model evaluation benefit from
the serious conflicts and the symmetric conditions. The evaluation framework
contains four distribution indexes and two time series indexes in space and
time dimensions, and they are respectively graded A traditional social force
model and a Voronoi diagram based modification are introduced to test the
evaluation framework. The evaluation results show that the framework is
beneficial to evaluate pedestrian models and even reflects the minor
differences between the models.
