A Trajectory-free Crash Detection Framework with Generative Approach and Segment Map Diffusion

TL;DR

This paper introduces a novel two-stage, trajectory-free crash detection framework using a diffusion-based model to generate and compare road segment maps, improving real-time crash detection without relying on vehicle trajectories.

Contribution

The paper presents a new diffusion-based segment map generation model, Mapfusion, integrated into a two-stage crash detection framework that operates without vehicle trajectory data.

Findings

Mapfusion effectively generates realistic road segment evolution maps.

The framework accurately detects crashes in real-world scenarios.

Robustness across different sampling intervals demonstrated.

Abstract

Real-time crash detection is essential for developing proactive safety management strategy and enhancing overall traffic efficiency. To address the limitations associated with trajectory acquisition and vehicle tracking, road segment maps recording the individual-level traffic dynamic data were directly served in crash detection. A novel two-stage trajectory-free crash detection framework, was present to generate the rational future road segment map and identify crashes. The first-stage diffusion-based segment map generation model, Mapfusion, conducts a noisy-to-normal process that progressively adds noise to the road segment map until the map is corrupted to pure Gaussian noise. The denoising process is guided by sequential embedding components capturing the temporal dynamics of segment map sequences. Furthermore, the generation model is designed to incorporate background context through ControlNet to enhance generation control. Crash detection is achieved by comparing the monitored segment map with the generations from diffusion model in second stage. Trained on non-crash vehicle motion data, Mapfusion successfully generates realistic road segment evolution maps based on learned motion patterns and remains robust across different sampling intervals. Experiments on real-world crashes indicate the effectiveness of the proposed two-stage method in accurately detecting crashes.