  A spreading process can be observed when particular information, substances,
or diseases spread through a population over time in social and biological
systems. It is widely believed that contact interactions among individual
entities play an essential role in the spreading process. Although contact
interactions are often influenced by geometrical conditions, little attention
has been paid to understand their effects, especially on contact duration among
pedestrians. To examine how the pedestrian flow setups affect contact duration
distribution, we have analyzed trajectories of pedestrians in contact
interactions collected from pedestrian flow experiments of uni-, bi- and
multi-directional setups. Based on turning angle entropy and efficiency, we
have classified the type of motion observed in the contact interactions. We
have found that the majority of contact interactions in the unidirectional flow
setup can be categorized as confined motion, hinting at the possibility of
long-lived contact duration. However, ballistic motion is more frequently
observed in the other flow conditions, yielding frequent, brief contact
interactions. Our results demonstrate that observing more confined motions is
likely associated with the increase of parallel contact interactions regardless
of pedestrian flow setups. This study highlights that the confined motions tend
to yield longer contact duration, suggesting that the infectious disease
transmission risk would be considerable even for low transmissibility. These
results have important implications for crowd management in the context of
minimizing spreading risk. This work is an extended version of Kwak et al.
(2023) presented at the 2023 International Conference on Computational Science
(ICCS).
