Priority Flicker in Risk-Based Pedestrian Prioritization: A Baseline Temporal Stability Assessment on the ETH/UCY Benchmark

Abstract

Risk-based prioritization frameworks such as the Intelligent Pedestrian Model (IPM) rank pedestrians by an instantaneous, reference-normalized risk score. They indicate which pedestrian requires attention first. This study examines the temporal stability of such rankings. We computed an observation-only kinematic Exposure proxy frame by frame on three ETH/UCY benchmark scenes. In these scenes, the highest-priority identity changes rapidly: the median top-1 persistence is two frames (0.8 s). We introduce a switch classification that separates established switches from entry-driven and forced switches. Grace-period exclusion is evaluated as a sensitivity variant and shown to remove up to 82% of evaluable time in short-track scenes. Established flicker rates range from one switch per 2.7 s in dense scenes to one per 25.4 s in sparse scenes, with switches concentrated at small top-1–top-2 risk gaps. The results show that instantaneous rankings alone may be insufficient for sustained attention allocation and motivate future work on temporal priority management.