A Dynamic, Context-Aware Framework for Risky Driving Prediction Using Naturalistic Data

Naturalistic driving studies offer a powerful means for observing and quantifying real-world driving behaviour. One of their prominent applications in traffic safety is the continuous monitoring and classification of risky driving behaviour. However, many existing frameworks rely on fixed time windows and static thresholds for distinguishing between safe and risky behaviour - limiting their ability to respond to the stochastic nature of real-world driving. This study proposes a dynamic and individualised framework for identifying risky driving behaviour using Belgian naturalistic driving data. The approach leverages a rolling time window and bi-level optimisation to dynamically calibrate both risk thresholds and model hyperparameters, capturing subtle behavioural shifts. Two safety indicators, speed-weighted headway and harsh driving events, were evaluated using three data-driven models: Random Forest, XGBoost, and Deep Neural Network (DNN). The DNN demonstrated strong capability in capturing subtle changes in driving behaviour, particularly excelling in high-recall tasks, making it promising for early-stage risk detection. XGBoost provided the most balanced and stable performance across different thresholds and evaluation metrics. While random forest showed more variability, it responded sensitively to dynamic threshold adjustments, which may be advantageous during model adaptation or tuning. Speed-weighted headway emerged as a more stable and context-sensitive risk indicator than harsh driving events, likely due to its robustness to label sparsity and contextual variation. Overall, the findings support the value of adaptive, personalised risk detection approaches for enhancing real-time safety feedback and tailoring driver support in intelligent transport systems.