RiskProp: Collision-Anchored Self-supervised Temporal Constraints for Early Accident Anticipation

Accident anticipation aims to predict impending collisions from dashcam videos and trigger early alerts. Existing methods rely on binary supervision with manually annotated “anomaly onset” frames, which are subjective and inconsistent, leading to inaccurate risk estimation. In contrast, we propose Risk Propagation (RiskProp), a collision-anchored supervised framework enhanced with self-supervised temporal constraints, which removes the need for anomaly onset annotations by leveraging only the reliably labeled collision frame. RiskProp models temporal risk evolution through two observation-driven losses: first, since future frames contain more definitive evidence of an impending accident, we introduce a future-frame regularization loss that uses the model’s next-frame prediction as a soft target to supervise the current frame, enabling backward propagation of risk signals; second, inspired by the empirical trend of rising risk before accidents, we design an adaptive monotonic constraint to encourage a non-decreasing progression over time. Experiments on CAP-DATA and Nexar demonstrate that RiskProp achieves state-of-the-art performance and produces smoother, more discriminative risk curves, improving both early anticipation and interpretability.