D3-Guard: Acoustic-based Drowsy Driving Detection Using Smartphones
This study addresses the limitation of existing fatigue-driving detection systems that rely on dedicated hardware. We propose a passive, smartphone-based acoustic sensing method leveraging built-in microphones to capture subtle Doppler-induced frequency shifts in ambient sound—caused by drowsiness-related behaviors such as yawning, head nodding, and steering wheel rotation. To enable efficient on-device processing, we introduce a lightweight undersampling–FFT feature extraction pipeline and develop an LSTM-based temporal model for early fatigue onset detection, achieving >80% detection accuracy within 70% of the behavioral event duration. To our knowledge, this is the first purely smartphone-microphone-driven acoustic fatigue detection framework. Evaluated on real-road driving data from five participants, the system achieves a mean classification accuracy of 93.31%, with low latency and strong potential for real-time, practical deployment.