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 established switches concentrated at small score differences between competing pedestrians. The results show that instantaneous rankings alone may be insufficient for sustained attention allocation and motivate future work on temporal priority management.