Classifying pedestrian crossing flows: A data-driven approach using fundamental diagrams and machine learning

This study investigates the dynamics of pedestrian crossing flows with varying crossing angles $\alpha$ to classify different scenarios and derive implications for crowd management. Probability density functions of four key features$-$velocity $v$, density $\rho$, avoidance number $Av$, and intrusion number $In$$-$were analyzed to characterize pedestrian behavior. Velocity-density fundamental diagrams were constructed for each $\alpha$ and fitted with functional forms from existing literature. Classification attempts using $Av$-$In$ and $v$-$\rho$ phase spaces revealed significant overlaps, highlighting the limitations of these metrics alone for scenario differentiation. To address this, machine learning models, including logistic regression and random forest, were employed using all four features. Results showed robust classification performance, with $v$ and $Av$ contributing most significantly. Insights from feature importance metrics and classification accuracy offer practical guidance for managing high-density crowds, optimizing pedestrian flow, and designing safer public spaces. These findings provide a data-driven framework for advancing pedestrian dynamics research.